A comparative study on the effects of electron beam irradiation on imidacloprid-resistant and -susceptible Aphis gossypii (Hemiptera: Aphididae)

NASA Astrophysics Data System (ADS)

Yun, Seung-Hwan; Koo, Hyun-Na; Lee, Seon-Woo; Kim, Hyun Kyung; Kim, Yuri; Han, Bumsoo; Kim, Gil-Hah

2015-07-01

The melon and cotton aphid, Aphis gossypii, is a polyphagous insect pest. This study compared the development, reproduction, DNA damage, recovery, and gene expression in imidacloprid-resistant (IMI-R) and -susceptible (S) strains of A. gossypii by electron beam irradiation. When 1st instar nymphs were irradiated with 100 Gy, the fecundity (nymphs of F1 generation) of the resultant adults were completely inhibited. When adults were irradiated with 200 Gy, the number of total 1st instar nymphs produced per adult was 3.0±1.7 and 1.9±1.4 in the S and IMI-R strains, respectively, but adult development was completely suppressed. However, electron beam irradiation did not affect adult longevity in either the S or IMI-R strain. There was no statistically significant difference between the effect of irradiation on the S and IMI-R strains. Therefore, electron beam irradiation at 200 Gy could be used as a phytosanitary irradiation treatment for both S and IMI-R strains of A. gossypii. The DNA damage caused by electron beam irradiation was evaluated by an alkaline comet assay. Exposure to an electron beam (50 Gy) induced DNA damage that was repaired to a similar level as the untreated control group (0 Gy) over time. However, at more than 100 Gy, the DNA damage was not completely repaired. The expression of P450, HSP70, cuticle protein, and elongation factor genes were higher in the IMI-R strain than in the S strain.

Evaluation of Brucella abortus strain RB51 and strain 19 in pronghorn antelope

USGS Publications Warehouse

Elzer, P.H.; Smith, J.; Roffe, T.; Kreeger, T.; Edwards, J.; Davis, D.

2002-01-01

Free-roaming elk and bison in the Greater Yellowstone Area remain the only wildlife reservoirs for Brucella abortus in the United States, and the large number of animals and a lack of holding facilities make it unreasonable to individually vaccinate each animal. Therefore, oral delivery is being proposed as a possible option to vaccinate these wild ungulates. One of the main problems associated with oral vaccination is the potential exposure of nontarget species to the vaccines. The purpose of this study was to determine the effects of two Brucella vaccines, strain 19 (S19) and the rough strain RB51 (SRB51), in pregnant pronghorn antelope. We conclude that S19 and SRB51 rarely colonize maternal and fetal tissues of pregnant pronghorn and were not associated with fetal death. Oral delivery of either vaccine at this dose appears to be nonhazardous to pregnant pronghorn.

Comparative Transcriptome Analysis of Vibrio splendidus JZ6 Reveals the Mechanism of Its Pathogenicity at Low Temperatures

PubMed Central

Liu, Rui; Chen, Hao; Zhang, Ran; Zhou, Zhi; Hou, Zhanhui; Gao, Dahai; Zhang, Huan; Wang, Lingling

2016-01-01

Yesso scallop-pathogenic Vibrio splendidus strain JZ6 was found to have the highest virulence at 10°C, while its pathogenicity was significantly reduced with increased temperature and completely incapacitated at 28°C. In the present study, comparative transcriptome analyses of JZ6 and another nonpathogenic V. splendidus strain, TZ19, were conducted at two crucial culture temperatures (10°C and 28°C) in order to determine the possible mechanism of temperature regulation of virulence. Comparisons among four libraries, constructed from JZ6 and TZ19 cultured at 10°C and 28°C (designated JZ6_10, JZ6_28, TZ19_10, and TZ19_28), revealed that 241 genes were possibly related to the increased virulence of JZ6 at 10°C. There were 10 genes, including 2 encoding Flp pilus assembly proteins (FlhG and VS_2437), 6 encoding proteins of the “Vibrio cholerae pathogenic cycle” (ToxS, CqsA, CqsS, RpoS, HapR, and Vsm), and 2 encoding proteins in the Sec-dependent pathway (SecE and FtsY), that were significantly upregulated in JZ6_10 (P < 0.05) compared to those in JZ6_28, TZ19_10, and TZ19_28, which were supposed to be responsible for adhesion, quorum sensing, virulence, and protein secretion of V. splendidus. When cultured at 10°C, JZ6 cells were larger and tended to aggregate more than those cultured at 28°C. The virulence factor (extracellular metalloprotease) was also found to be highly expressed in the extracellular product (ECP) of JZ6 at 10°C, and this ECP exhibited obvious cytotoxicity to oyster primary hemocytes, A549 cells, and L929 cells. These results indicated that low temperatures (10°C) could enhance adhesion, activate the quorum sensing systems, upregulate virulence factor synthesis and secretion, and, lastly, increase the pathogenicity of JZ6. PMID:26801576

The phosphotransferase system-dependent sucrose utilization regulon in enteropathogenic Escherichia coli strains is located in a variable chromosomal region containing iap sequences.

PubMed

Treviño-Quintanilla, Luis Gerardo; Escalante, Adelfo; Caro, Alma Delia; Martínez, Alfredo; González, Ricardo; Puente, José Luis; Bolívar, Francisco; Gosset, Guillermo

2007-01-01

The capacity to utilize sucrose as a carbon and energy source (Scr(+) phenotype) is a highly variable trait among Escherichia coli strains. In this study, seven enteropathogenic E. coli (EPEC) strains from different sources were studied for their capacity to grow using sucrose. Liquid media cultures showed that all analyzed strains have the Scr(+) phenotype and two distinct groups were defined: one of five and another of two strains displaying doubling times of 67 and 125 min, respectively. The genes conferring the Scr(+) phenotype in one of the fast-growing strains (T19) were cloned and sequenced. Comparative sequence analysis revealed that this strain possesses the scr regulon genes scrKYABR, encoding phosphoenolpyruvate:phosphotransferase system-dependent sucrose transport and utilization activities. Transcript level quantification revealed sucrose-dependent induction of scrK and scrR genes in fast-growing strains, whereas no transcripts were detected in slow-growing strains. Sequence comparison analysis revealed that the scr genes in strain T19 are almost identical to those present in the scr regulon of prototype EPEC E2348/69 and in both strains, the scr genes are inserted in the chromosomal intergenic region of hypothetical genes ygcE and ygcF. Comparison of the ygcE-ygcF intergenic region sequence of strains MG1655, enterohemorrhagic EDL933, uropathogenic ECFT073 and EPEC T19-E2348/69 revealed that the number of extragenic highly repeated iap sequences corresponded to nine, four, two and none, respectively. These results show that the iap sequence-containing chromosomal ygcE-ygcF intergenic region is highly variable in E. coli. Copyright (c) 2007 S. Karger AG, Basel.

Reconstructing genome evolution in historic samples of the Irish potato famine pathogen

PubMed Central

Martin, Michael D.; Cappellini, Enrico; Samaniego, Jose A.; Zepeda, M. Lisandra; Campos, Paula F.; Seguin-Orlando, Andaine; Wales, Nathan; Orlando, Ludovic; Ho, Simon Y. W.; Dietrich, Fred S.; Mieczkowski, Piotr A.; Heitman, Joseph; Willerslev, Eske; Krogh, Anders; Ristaino, Jean B.; Gilbert, M. Thomas P.

2013-01-01

Responsible for the Irish potato famine of 1845–49, the oomycete pathogen Phytophthora infestans caused persistent, devastating outbreaks of potato late blight across Europe in the 19th century. Despite continued interest in the history and spread of the pathogen, the genome of the famine-era strain remains entirely unknown. Here we characterize temporal genomic changes in introduced P. infestans. We shotgun sequence five 19th-century European strains from archival herbarium samples—including the oldest known European specimen, collected in 1845 from the first reported source of introduction. We then compare their genomes to those of extant isolates. We report multiple distinct genotypes in historical Europe and a suite of infection-related genes different from modern strains. At virulence-related loci, several now-ubiquitous genotypes were absent from the historical gene pool. At least one of these genotypes encodes a virulent phenotype in modern strains, which helps explain the 20th century’s episodic replacements of European P. infestans lineages. PMID:23863894

Gaetbulimicrobium brevivitae gen. nov., sp. nov., a novel member of the family Flavobacteriaceae isolated from a tidal flat of the Yellow Sea in Korea.

PubMed

Yoon, Jung-Hoon; Kang, So-Jung; Jung, Seo-Youn; Oh, Hyun Woo; Oh, Tae-Kwang

2006-01-01

A Gram-negative, non-spore-forming and rod-shaped gliding bacterium, designated strain SMK-19T, was isolated from a tidal flat sediment of the Yellow Sea, Korea, and its taxonomic position was investigated by using a polyphasic approach. Strain SMK-19T grew optimally at 37 degrees C, in the presence of 2-3 % (w/v) NaCl and at pH 7.0-8.0. It contained MK-6 as the predominant menaquinone, and iso-C(17 : 0) 3-OH and iso-C(15 : 0) as the major fatty acids. Major polar lipids were phosphatidylethanolamine, unidentified phospholipids and an amino-group-containing lipid that is ninhydrin-positive. The DNA G+C content was 36.0 mol%. Phylogenetic analyses based on 16S rRNA gene sequences demonstrated that strain SMK-19T formed a distinct evolutionary lineage within the family Flavobacteriaceae. The 16S rRNA gene sequence of strain SMK-19T exhibited similarity values of <94.4 % to those of other members of the family Flavobacteriaceae. Strain SMK-19T was distinguished from phylogenetically related genera by differences in several phenotypic properties. On the basis of phenotypic, phylogenetic and chemotaxonomic data, SMK-19T (= KCTC 12390T = DSM 17196T) was classified at the type strain of a novel genus and species, Gaetbulimicrobium brevivitae gen. nov., sp. nov.

Limnobacter litoralis sp. nov., a thiosulfate-oxidizing, heterotrophic bacterium isolated from a volcanic deposit, and emended description of the genus Limnobacter.

PubMed

Lu, Hongsheng; Sato, Yoshinori; Fujimura, Reiko; Nishizawa, Tomoyasu; Kamijo, Takashi; Ohta, Hiroyuki

2011-02-01

A Gram-negative, aerobic, heterotrophic bacterium, designated KP1-19(T), was isolated from a 22-year-old volcanic deposit at a site lacking vegetation on the island of Miyake, Japan. Strain KP1-19(T) was able to use thiosulfate (optimum concentration 10 mM) as an additional energy source. 16S rRNA gene sequence analysis indicated that strain KP1-19(T) was closely related to Limnobacter thiooxidans CS-K2(T) within the class Betaproteobacteria (97.7 % 16S rRNA gene sequence similarity). The cellular fatty acid profile was characteristic of the genus Limnobacter: the major fatty acids (>5 %) were C(16 : 0), C(16 : 1)ω7c and C(18 : 1)ω7c and minor amounts of C(10 : 0) 3-OH were also found. DNA-DNA relatedness between strain KP1-19(T) and L. thiooxidans LMG 19593(T) was 18 %. Therefore, strain KP1-19(T) represents a novel species, for which the name Limnobacter litoralis sp. nov. is proposed. The type strain is KP1-19(T) (=LMG 24869(T) =NBRC 105857(T) =CIP 109929(T)).

Nitrincola alkalilacustris sp. nov. and Nitrincola schmidtii sp. nov., alkaliphilic bacteria isolated from soda pans, and emended description of the genus Nitrincola.

PubMed

Borsodi, Andrea K; Korponai, Kristóf; Schumann, Peter; Spröer, Cathrin; Felföldi, Tamás; Márialigeti, Károly; Szili-Kovács, Tibor; Tóth, Erika

2017-12-01

Three alkaliphilic and halotolerant bacterial strains, designated ZV-19 T , R4-8 T and S4-12, were isolated from the water of soda pans located in the Kiskunság National Park, Hungary. Cells of all three strains were Gram-staining-negative, rod-shaped, motile and non-endospore-forming. They were facultatively anaerobic, and oxidase- and catalase-positive. Their major isoprenoid quinone was Q-8, and their predominant fatty acids were C18 : 1ω7c, C16 : 1ω7c and C16 : 0. The DNA G+C content was 54.5 mol% in strain ZV-19 T and 45.8 mol% in strain R4-8 T . The 16S rRNA gene based phylogenetic analysis showed that all three strains were members of the genus Nitrincola (family Oceanospirillaceae, class Gammaproteobacteria). Strain ZV-19 T showed 96.6 and 95.5 % sequence similarities and 19±3 and 18±3 % DNA-DNA relatedness to Nitrincolalacisaponensis DSM 16316 T and Nitrincolaalkalisediminis JCM 19317 T , respectively. Strains R4-8 T and S4-12 exhibited 97.9 and 98.6 % sequence matches and 34±4 and 13±8 % DNA-DNA hybridization values with N. lacisaponensis DSM 16316 T and N. alkalisediminis JCM 19317 T , respectively. According to the phenotypic, chemotaxonomic and phylogenetic data, the strains studied represent two novel species, Nitrincola alkalilacustris sp. nov. with the type strain ZV-19 T (=DSM 29817 T =NCAIM B 02612 T ) and Nitrincola schmidtii sp. nov. with the type strain R4-8 T (=DSM 100788 T =NCAIM B.02626 T ). An emended description of the genus Nitrincola is also presented.

Reclassification of Paenibacillus riograndensis as a Genomovar of Paenibacillus sonchi: Genome-Based Metrics Improve Bacterial Taxonomic Classification

PubMed Central

Sant’Anna, Fernando H.; Ambrosini, Adriana; de Souza, Rocheli; de Carvalho Fernandes, Gabriela; Bach, Evelise; Balsanelli, Eduardo; Baura, Valter; Brito, Luciana F.; Wendisch, Volker F.; de Oliveira Pedrosa, Fábio; de Souza, Emanuel M.; Passaglia, Luciane M. P.

2017-01-01

Species from the genus Paenibacillus are widely studied due to their biotechnological relevance. Dozens of novel species descriptions of this genus were published in the last couple of years, but few utilized genomic data as classification criteria. Here, we demonstrate the importance of using genome-based metrics and phylogenetic analyses to identify and classify Paenibacillus strains. For this purpose, Paenibacillus riograndensis SBR5T, Paenibacillus sonchi X19-5T, and their close relatives were compared through phenotypic, genotypic, and genomic approaches. With respect to P. sonchi X19-5T, P. riograndensis SBR5T, Paenibacillus sp. CAR114, and Paenibacillus sp. CAS34 presented ANI (average nucleotide identity) values ranging from 95.61 to 96.32%, gANI (whole-genome average nucleotide identity) values ranging from 96.78 to 97.31%, and dDDH (digital DNA–DNA hybridization) values ranging from 68.2 to 73.2%. Phylogenetic analyses of 16S rRNA, gyrB, recA, recN, and rpoB genes and concatenated proteins supported the monophyletic origin of these Paenibacillus strains. Therefore, we propose to assign Paenibacillus sp. CAR114 and Paenibacillus sp. CAS34 to P. sonchi species, and reclassify P. riograndensis SBR5T as a later heterotypic synonym of P. sonchi (type strain X19-5T), with the creation of three novel genomovars, P. sonchi genomovar Sonchi (type strain X19-5T), P. sonchi genomovar Riograndensis (type strain SBR5T), P. sonchi genomovar Oryzarum (type strain CAS34T = DSM 102041T; = BR10511T). PMID:29046663

Comparative effectiveness of Pseudomonas and Serratia sp. containing ACC-deaminase for improving growth and yield of wheat (Triticum aestivum L.) under salt-stressed conditions.

PubMed

Zahir, Zahir Ahmad; Ghani, Usman; Naveed, Muhammad; Nadeem, Sajid Mahmood; Asghar, Hafiz Naeem

2009-05-01

Ethylene synthesis is accelerated in response to various environmental stresses like salinity. Ten rhizobacterial strains isolated from wheat rhizosphere taken from different salt affected areas were screened for growth promotion of wheat under axenic conditions at 1, 5, 10 and 15 dS m(-1). Three strains, i.e., Pseudomonas putida (N21), Pseudomonas aeruginosa (N39) and Serratia proteamaculans (M35) showing promising performance under axenic conditions were selected for a pot trial at 1.63 (original), 5, 10 and 15 dS m(-1). Results showed that inoculation was effective even in the presence of higher salinity levels. P. putida was the most efficient strain compared to the other strains and significantly increased the plant height, root length, grain yield, 100-grain weight and straw yield up to 52, 60, 76, 19 and 67%, respectively, over uninoculated control at 15 dS m(-1). Similarly, chlorophyll content and K(+)/Na(+) of leaves also increased by P. putida over control. It is highly likely that under salinity stress, 1-aminocyclopropane-1-carboxylic acid-deaminase activity of these microbial strains might have caused reduction in the synthesis of stress (salt)-induced inhibitory levels of ethylene. The results suggested that these strains could be employed for salinity tolerance in wheat; however, P. putida may have better prospects in stress alleviation/reduction.

Acidovorax valerianellae sp. nov., a novel pathogen of lamb's lettuce [Valerianella locusta (L.) Laterr].

PubMed

Gardan, Louis; Stead, David E; Dauga, Catherine; Gillis, Moniek

2003-05-01

Bacterial spot disease of lamb's lettuce [Valerianella locusta (L.) Laterr.] was first observed in fields in 1991. This new bacterial disease is localized in western France in high-technology field production of lamb's lettuce for the preparation of ready-to-use salad. Nineteen strains isolated in 1992 and 1993 from typical black leaf spots of naturally infected lamb's lettuce were characterized and compared with reference strains of Acidovorax and Delftia. The pathogenicity of the 19 strains was confirmed by artificial inoculation. Biochemical and physiological tests, fatty acid profiles, DNA-DNA hybridization and other nucleic acid-based tests were performed. A numerical taxonomic analysis of the 19 lamb's lettuce strains showed a single homogeneous phenon closely related to previously described phytopathogenic taxa of the genus Acidovorax. DNA-DNA hybridization studies showed that the lamb's lettuce strains were 91-100% related to a representative strain, strain CFBP 4730(T), and constituted a discrete DNA hybridization group, indicating that they belong to the same novel species. Results from DNA-rRNA hybridization, 16S rRNA sequence analysis and fatty acid analysis studies confirmed that this novel species belongs to the beta-subclass of the Proteobacteria and, more specifically, to the family Comamonadaceae and the genus Acidovorax. The name Acidovorax valerianellae sp. nov. is proposed for this novel taxon of phytopathogenic bacteria. The type strain is strain CFBP 4730(T) (= NCPPB 4283(T)).

Lactobacillus formosensis sp. nov., a lactic acid bacterium isolated from fermented soybean meal.

PubMed

Chang, Chi-huan; Chen, Yi-sheng; Lee, Tzu-tai; Chang, Yu-chung; Yu, Bi

2015-01-01

A Gram-reaction-positive, catalase-negative, facultatively anaerobic, rod-shaped lactic acid bacterium, designated strain S215(T), was isolated from fermented soybean meal. The organism produced d-lactic acid from glucose without gas formation. 16S rRNA gene sequencing results showed that strain S215(T) had 98.74-99.60 % sequence similarity to the type strains of three species of the genus Lactobacillus (Lactobacillus farciminis BCRC 14043(T), Lactobacillus futsaii BCRC 80278(T) and Lactobacillus crustorum JCM 15951(T)). A comparison of two housekeeping genes, rpoA and pheS, revealed that strain S215(T) was well separated from the reference strains of species of the genus Lactobacillus. DNA-DNA hybridization results indicated that strain S215(T) had DNA related to the three type strains of species of the genus Lactobacillus (33-66 % relatedness). The DNA G+C content of strain S215(T) was 36.2 mol%. The cell walls contained peptidoglycan of the d-meso-diaminopimelic acid type and the major fatty acids were C18 : 1ω9c, C16 : 0 and C19 : 0 cyclo ω10c/C19 : 1ω6c. Phenotypic and genotypic features demonstrated that the isolate represents a novel species of the genus Lactobacillus, for which the name Lactobacillus formosensis sp. nov. is proposed. The type strain is S215(T) ( = NBRC 109509(T) = BCRC 80582(T)). © 2015 IUMS.

Effect of wine-based marinades on the behavior of Salmonella Typhimurium and background flora in beef fillets.

PubMed

Nisiotou, A; Chorianopoulos, N G; Gounadaki, A; Panagou, E Z; Nychas, G-J E

2013-06-17

The aim of this study was to evaluate the wine-based marinades to control the survival of acid-adapted and non-adapted Salmonella Typhimurium and background flora of fresh beef stored aerobically or under modified atmosphere. Beef slices were inoculated with a 3-strain cocktail of acid-adapted or non-adapted Salmonella Typhimurium strains DT 193, 4/74 and DSM 554 and marinated by immersion in wine (W) or wine supplemented with 0.3% thyme essential oil (WEO), for 12h at 4°C. Marinated slices were then stored under air or modified atmosphere conditions at 5°C. S. Typhimurium and background flora were followed for a 19-day period of storage. S. Typhimurium individual strains were monitored by pulsed field gel electrophoresis. Marination with wine significantly (P<0.05) reduced the background flora compared to the control (non-marinated). Furthermore, immersion of fillets in W or WEO marinades for 12h significantly (P<0.05) reduced the levels of S. Typhimurium compared to the non-marinated (control) samples by 1.1 and 1.4logCFU/g or 2.0 and 1.9logCFU/g for acid-adapted and non-adapted cells, respectively. Acid-adapted cells were more susceptible (P<0.05) to the addition of thyme essential oil in the wine marinade. The epidemic multi-drug resistant DT 193, the 4/74 and DSM 554 strains survived marination (for both W and WEO) and were detected at about similar proportions as revealed by PFGE results. Present results indicate that wine-based marinades are efficient, from a safety and shelf life stand point, in reducing pathogen's levels as well as the background beef flora. Copyright © 2013 Elsevier B.V. All rights reserved.

Physical Simulation of a Duplex Stainless Steel Friction Stir Welding by the Numerical and Experimental Analysis of Hot Torsion Tests

NASA Astrophysics Data System (ADS)

da Fonseca, Eduardo Bertoni; Santos, Tiago Felipe Abreu; Button, Sergio Tonini; Ramirez, Antonio Jose

2016-09-01

Physical simulation of friction stir welding (FSW) by means of hot torsion tests was performed on UNS S32205 duplex stainless steel. A thermomechanical simulator Gleeble 3800® with a custom-built liquid nitrogen cooling system was employed to reproduce the thermal cycle measured during FSW and carry out the torsion tests. Microstructures were compared by means of light optical microscopy and electron backscatter diffraction. True strain and strain rate were calculated by numerical simulation of the torsion tests. Thermomechanically affected zone (TMAZ) was reproduced at peak temperature of 1303 K (1030 °C), rotational speeds of 52.4 rad s-1 (500 rpm) and 74.5 rad s-1 (750 rpm), and 0.5 to 0.75 revolutions, which represent strain rate between 10 and 16 s-1 and true strain between 0.5 and 0.8. Strong grain refinement, similar to the one observed in the stir zone (SZ), was attained at peak temperature of 1403 K (1130 °C), rotational speed of 74.5 rad s-1 (750 rpm), and 1.2 revolution, which represent strain rate of 19 s-1 and true strain of 1.3. Continuous dynamic recrystallization in ferrite and dynamic recrystallization in austenite were observed in the TMAZ simulation. At higher temperature, dynamic recovery of austenite was also observed.

The Multiphase Rheology of Andesitic Magmas from the 1.9ka Eruption of Turrialba Volcano (Costa Rica)

NASA Astrophysics Data System (ADS)

Vona, A.; Di Piazza, A.; Romano, C.; De Astis, G.; Soto, G. J.

2014-12-01

We present a study of high-temperature, uniaxial deformation experiments of natural magma from an andesitic eruption of Turrialba volcano (1.9ka Plinian eruption). The aim of this work is to investigate the multiphase rheology (liquid+vesicles+crystals) of natural samples and the effect of vesicles and crystals on the magma viscosity. The experiments were performed using a high-temperature uniaxial Geocomp LoadTrac II press at dry atmospheric conditions and controlled deformation rates. Cores of natural sample (with Φcrys=0.20-0.30 and Φves=0.41-0.58) were deformed isothermally (790-870°C) at variable strain rates (VSR, from 10-6 to 10-4 s-1) and constant strain rate (CSR, 10-5 s-1). VSR were performed at low total amount of strain (e<0.10) to parameterize the flow behavior of these complex natural materials. The stress-strain rate relationships under flow conditions showed a linear trend between the applied stress and strain rate in the temperature interval investigated. All the samples display a steep linear trend, typical of Newtonian fluids (n index ~ 1), with a very small shear thinning behavior. CSR tests were performed at different total amount of strain (e=0.15-0.25-0.35). Strain hardening was observed with increasing deformation, resulting in an increase of apparent viscosity (up to 100.5 Pa s). This increase is related to the loss of total porosity (up to ΔΦves=0.15) due to compaction of the sample as indicated by post-run analyses . The measured multiphase rheology of Turrialba magmas was compared with literature models for both crystal- and bubble-bearing suspension. We calculate a difference of ~101 Pa s in magma apparent viscosity between high and low density samples, that coupled with a lateral temperature gradient inside the conduit of the volcano, could increase up to ~103 Pa s. The large difference in viscosity could be responsible of significant rheological contrasts, possibly resulting in strain localization and brittle fragmentation of magma.

Lactobacillus musae sp. nov., a novel lactic acid bacterium isolated from banana fruits.

PubMed

Chen, Yi-Sheng; Wang, Li-Ting; Liao, Yu-Jou; Lan, Yi-Shan; Chang, Chi-Huan; Chang, Yu-Chung; Wu, Hui-Chung; Lo, Huei-Yin; Otoguro, Misa; Yanagida, Fujitoshi

2017-12-01

Two Gram-stain-positive, catalase-negative, rod-shaped, bacterial strains (313 T and 311) were isolated from banana fruits in Taiwan. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the highest similarity to both strains corresponded to the type strain of Lactobacillus nantensis (99.19 %), followed by Lactobacillus crustorum (98.99 %), Lactobacillus heilongjiangensis (98.59 %) and Lactobacillus farciminis (98.52 %). Phylogenetic analysis based on the sequences of two housekeeping genes, pheS and rpoA, revealed that these two strains were well separated from the Lactobacillus reference strains. DNA-DNA relatedness values revealed genotype separation of the two strains from the above four species. The DNA G+C content of strain 313 T was 35.5 mol%. The strains were homofermentative and mainly produced l-lactic acid from glucose. The major cellular fatty acids of strain 313 T were 18 : 1ω6c and/or 18 : 1ω7c, 16 : 0, and 19 : 1ω6c and/or 19 : 0 cyclo ω10c. Based on their physiological and genotypic characteristics, the isolates represent a novel species of the genus Lactobacillus, for which the name Lactobacillusmusae sp. nov. is proposed. The type strain is 313 T =NBRC 112868 T =BCRC 81020 T ).

Combined Effects and Cross-Interactions of Different Antibiotics and Polypeptides in Salmonella bredeney.

PubMed

Ju, Xiangyu; Zhu, Mengjiao; Han, Jinzhi; Lu, Zhaoxin; Zhao, Haizhen; Bie, Xiaomei

2018-05-24

Salmonella spp. are health-threatening foodborne pathogens. The increasingly common spread of antibiotic-resistant Salmonella spp. is a major public healthcare issue worldwide. In this study, we wished to explore (1) antibiotic or polypeptide combinations to inhibit multidrug-resistant Salmonella bredeney and (2) the regulation of cross-resistance and collateral sensitivity of antibiotics and polypeptides. We undertook a study to select antibiotic combinations. Then, we promoted drug-resistant strains of S. bredeney after 15 types of antibiotic treatment. From each evolving population, the S. bredeney strain was exposed to a particular single drug. Then, we analyzed how the evolved S. bredeney strains acquired resistance or susceptibility to other drugs. A total of 105 combinations were tested against S. bredeney following the protocols of CLSI-2016 and EUCAST-2017. The synergistic interactions between drug pairings were diverse. Notably, polypeptides were more likely to be linked to synergistic combinations: 56% (19/34) of the synergistic pairings were relevant to polypeptides. Simultaneously, macrolides demonstrated antagonism toward polypeptides. The latter were more frequently related to collateral sensitivity than the other drugs because the other 13 drugs sensitized S. bredeney to polypeptides. In an experimental evolution involving 15 drugs, single drug-evolved strains were examined against the other 14 drugs, and the results were compared with the minimal inhibitory concentration of the ancestral strain. Single drug-evolved S. bredeney strains could alter the sensitivity to other drugs, and S. bredeney evolution against antibiotics could sensitize it to polypeptides.

Streptomyces songpinggouensis sp. nov., a Novel Actinomycete Isolated from Soil in Sichuan, China.

PubMed

Guan, Xuejiao; Li, Wenchao; Liu, Chongxi; Jin, Pinjiao; Guo, Siyu; Wang, Xiangjing; Xiang, Wensheng

2016-12-01

During a screening for novel and biotechnologically useful actinobacteria, a novel actinobacteria with weak antifungal activity, designated strain NEAU-Spg19 T , was isolated from a soil sample collected from pine forest in Songpinggou, Sichuan, southwest China. The strain was characterized using a polyphasic taxonomic approach which confirmed that it belongs to the genus Streptomyces. Growth occurred at a temperature range of 10-30 °C, pH 5.0-11.0 and NaCl concentrations of 0-5 %. The cell wall peptidoglycan consisted of LL-diaminopimelic acid and glycine. The major menaquinones were MK-9(H 6 ), MK-9(H 8 ) and MK-9(H 4 ). The phospholipid profile contained diphosphatidylglycerol (DPG), phosphatidylethanolamine and phosphatidylinositol. The major fatty acids were iso-C 15:0 , iso-C 16:0 , and C 16:0 . 16S rRNA gene sequence similarity studies showed that strain NEAU-Spg19 T belongs to the genus Streptomyces with the highest sequence similarities to Streptomyces tauricus JCM 4837 T (98.6 %) and Streptomyces rectiviolaceus JCM 9092 T (98.3 %). Some physiological and biochemical properties and low DNA-DNA relatedness values enabled the strain to be differentiated from S. tauricus JCM 4837 T and S. rectiviolaceus JCM 9092 T . Hence, on the basis of phenotypic and genetic analyses, it is proposed that strain NEAU-Spg19 T represents a novel species of the genus Streptomyces, for which the name Streptomyces songpinggouensis sp. nov. is proposed. The type strain is NEAU-Spg19 T (=CGMCC 4.7140 T =DSM 42141 T ).

Analysis of complete genome sequences of G9P[19] rotavirus strains from human and piglet with diarrhea provides evidence for whole-genome interspecies transmission of nonreassorted porcine rotavirus.

PubMed

Yodmeeklin, Arpaporn; Khamrin, Pattara; Chuchaona, Watchaporn; Kumthip, Kattareeya; Kongkaew, Aphisek; Vachirachewin, Ratchaya; Okitsu, Shoko; Ushijima, Hiroshi; Maneekarn, Niwat

2017-01-01

Whole genomes of G9P[19] human (RVA/Human-wt/THA/CMH-S070-13/2013/G9P[19]) and porcine (RVA/Pig-wt/THA/CMP-015-12/2012/G9P[19]) rotaviruses concurrently detected in the same geographical area in northern Thailand were sequenced and analyzed for their genetic relationships using bioinformatic tools. The complete genome sequence of human rotavirus RVA/Human-wt/THA/CMH-S070-13/2013/G9P[19] was most closely related to those of porcine rotavirus RVA/Pig-wt/THA/CMP-015-12/2012/G9P[19] and to those of porcine-like human and porcine rotaviruses reference strains than to those of human rotavirus reference strains. The genotype constellation of G9P[19] detected in human and piglet were identical and displayed as the G9-P[19]-I5-R1-C1-M1-A8-N1-T1-E1-H1 genotypes with the nucleotide sequence identities of VP7, VP4, VP6, VP1, VP2, VP3, NSP1, NSP2, NSP3, NSP4, and NSP5 at 99.0%, 99.5%, 93.2%, 97.7%, 97.7%, 85.6%, 89.5%, 93.2%, 92.9%, 94.0%, and 98.1%, respectively. The findings indicate that human rotavirus strain RVA/Human-wt/THA/CMH-S070-13/2013/G9P[19] containing the genome segments of porcine genetic backbone is most likely a human rotavirus of porcine origin. Our data provide an evidence of interspecies transmission and whole-genome transmission of nonreassorted G9P[19] porcine RVA to human occurring in nature in northern Thailand. Copyright © 2016. Published by Elsevier B.V.

Whole-Genome Sequence Analysis of Streptococcus pneumoniae Strains That Cause Hospital-Acquired Pneumonia Infections.

PubMed

Chang, Bin; Morita, Masatomo; Lee, Ken-Ichi; Ohnishi, Makoto

2018-05-01

Streptococcus pneumoniae colonizes the nasopharyngeal mucus in healthy individuals and can cause otitis media, pneumonia, and invasive pneumococcal diseases. In this study, we analyzed S. pneumoniae strains that caused 19 pneumonia episodes in long-term inpatients with severe underlying disease in a hospital during a period of 14 months (from January 2014 to February 2015). Serotyping and whole-genome sequencing analyses revealed that 18 of the 19 pneumonia cases were caused by S. pneumoniae strains belonging to 3 genetically distinct groups: clonal complex 9999 (CC9999), sequence type 282 (ST282), and ST166. The CC9999 and ST282 strains appeared to have emerged separately by a capsule switch from the pandemic PMEN 1 strain (Spain 23F -ST81). After all the long-term inpatients were inoculated with the 23-valent pneumococcal polysaccharide vaccine, no other nosocomial pneumonia infections occurred until March 2016. Copyright © 2018 American Society for Microbiology.

Bacillus niabensis sp. nov., isolated from cotton-waste composts for mushroom cultivation.

PubMed

Kwon, Soon-Wo; Lee, Seon-Young; Kim, Byung-Yong; Weon, Hang-Yeon; Kim, Jung-Bong; Go, Seung-Joo; Lee, Gil-Bok

2007-08-01

A group of five bacilli, designated strains 4T12, 4T19(T), 5M45, 5M53 and 5T52, isolated from cotton-waste composts for mushroom cultivation, were examined. These strains were Gram-positive, aerobic, motile, spore-forming rods. 16S rRNA gene sequence analyses revealed that the isolates belonged to the genus Bacillus, showing the highest levels of similarity (approx. 96.6-96.9 %) with respect to Bacillus herbersteinensis DSM 16534(T). The values for DNA-DNA hybridization (approx. 85-96 %) among these five strains revealed that they belong to the same species. The major menaquinone present was MK-7 and the predominant cellular fatty acids were anteiso-C(15 : 0) (approx. 24.5-33.9 %) and C(16 : 0) (approx. 15.1-34.1 %). The DNA G+C contents were 37.7-40.9 mol%. On the basis of physiological, biochemical, chemotaxonomic and comparative genomic analyses, the five isolates represent a novel species of the genus Bacillus, for which the name Bacillus niabensis sp. nov. is proposed. The type strain is 4T19(T) (=KACC 11279(T) =DSM 17723(T)).

Strengthen effects of dominant strains on aerobic digestion and stabilization of the residual sludge.

PubMed

Liu, Yongjun; Gao, Min; Zhang, Aining; Liu, Zhe

2017-07-01

In order to strengthen the aerobic digestion of residual sludge, shorten the time of sludge stabilization and further reduce operating costs, 3 dominant strains identified as Pseudomonas sp. L3, Acinetobacter sp. L16 and Bacillus sp. L19 were isolated from long-term aerobic digestion sludge. Results showed that the sludge stabilization time were reduced by 3-4days compared with the control when the dominant strains were added to the process of sludge aerobic digestion. The addition of dominant strains accelerated the accumulation of TOC, nitrate nitrogen and ammonia nitrogen in the digestive solution at different levels, and it was beneficial to the dissolution of phosphorus. Controlling DO 3-5mg/L, pH 6.5, the strains of Pseudomonas sp. L3 and Bacillus sp. L19 were combined dosing with the dosage of 2% in the process of sludge aerobic digestion, compared with the control, digestion rates of TOC and MLSS were increased about 19% and 16%, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

Identification of a novel fatty acid elongase with a wide substrate specificity from arachidonic acid-producing fungus Mortierella alpina 1S-4.

PubMed

Sakuradani, Eiji; Nojiri, Masutoshi; Suzuki, Haruna; Shimizu, Sakayu

2009-09-01

The isolation and characterization of a gene (MALCE1) that encodes a fatty acid elongase from arachidonic acid-producing fungus Mortierella alpina 1S-4 are described. MALCE1 was confirmed to encode a fatty acid elongase by its expression in yeast Saccharomyces cerevisiae, resulting in the accumulation of 18-, 19-, and 20-carbon monounsaturated fatty acids and eicosanoic acid. Furthermore, the MALCE1 yeast transformant efficiently elongated exogenous 9-hexadecenoic acid, 9,12-octadecadienoic acid, and 9,12,15-octadecatrienoic acid. The MALCE1 gene-silenced strain obtained from M. alpina 1S-4 exhibited a low content of octadecanoic acid and a high content of hexadecanoic acid, compared with those in the wild strain. The enzyme encoded by MALCE1 was demonstrated to be involved in the conversion of hexadecanoic acid to octadecanoic acid, its main role in M. alpina 1S-4.

Survey and properties of Staphylococcus aureus isolated from Japanese-style desserts.

PubMed

Shimamura, Yuko; Kidokoro, Shiho; Murata, Masatsune

2006-07-01

We surveyed the contamination of 315 Japanese- and western-style desserts and 247 human hands by Staphylococcus aureus and other staphylococcal bacteria. The most frequently isolated staphylococcal bacterium was S. warneri, followed by S. aureus. Only 1.9% of western-style desserts were contaminated by S. aureus strains, while 19.4% and 13.0% of Japanese-style desserts and human hands respectively were contaminated. Ninety-four isolates of S. aureus were characterized as to their biological properties and enterotoxigenicity. Although staphylococcal enterotoxins (SEs) were detected by enzyme-linked immunosorbent assay in the cultured broth of all S. aureus isolates, the reversed passive latex agglutination method and the polymerase chain reaction showed only 39 (41.5%) and 40 (42.6%) samples respectively as SE-positive. The predominant type of SE was SEB (67.5%), and eight strains produced SEA. None of the S. aureus strains had penicillin-binding protein 2', showing that methicillin-resistant S. aureus was not present in the samples.

[The occurrence of Streptococcus mutans variants in man and laboratory animals].

PubMed

Gehring, F; Karle, E J; Patz, J; Felfe, W; Bradatsch, U

1976-01-01

Numerous S. mutans strains isolated from human dental plaque and from that of rats and hamsters were classified by a well-known biochemical differentiation system for the separation of the serotypes "a to e", and by seven different biotypes (I-VII). 182 S. mutans strains from human plaque were assigned to the following serotypes: "c" = 68%, "d" = 19%, and "b" and "e" = 4% each. Serotype "a" was not found at all and 10 strains could not be classified. Out of 60 S. mutans strains from the oral cavity of rats, 85% belonged to serotype "c", while in 25 strains from hamsters serotypes "e" and "d" predominated.

Properties of a Ni(sub 19.5)Pd(sub 30)Ti(sub 50.5) high-temperature shape memory alloy in tension and compression

NASA Technical Reports Server (NTRS)

Noebe, Ronald; Padula, Santo, II; Bigelow, Glen; Rios, Orlando; Garg, Anita; Lerch, Brad

2006-01-01

Potential applications involving high-temperature shape memory alloys have been growing in recent years. Even in those cases where promising new alloys have been identified, the knowledge base for such materials contains gaps crucial to their maturation and implementation in actuator and other applications. We begin to address this issue by characterizing the mechanical behavior of a Ni19.5Pd30Ti50.5 high-temperature shape memory alloy in both uniaxial tension and compression at various temperatures. Differences in the isothermal uniaxial deformation behavior were most notable at test temperatures below the martensite finish temperature. The elastic modulus of the material was very dependent on strain level; therefore, dynamic Young#s Modulus was determined as a function of temperature by an impulse excitation technique. More importantly, the performance of a thermally activated actuator material is dependent on the work output of the alloy. Consequently, the strain-temperature response of the Ni19.5Pd30Ti50.5 alloy under various loads was determined in both tension and compression and the specific work output calculated and compared in both loading conditions. It was found that the transformation strain and thus, the specific work output were similar regardless of the loading condition. Also, in both tension and compression, the strain-temperature loops determined under constant load conditions did not close due to the fact that the transformation strain during cooling was always larger than the transformation strain during heating. This was apparently the result of permanent plastic deformation of the martensite phase with each cycle. Consequently, before this alloy can be used under cyclic actuation conditions, modification of the microstructure or composition would be required to increase the resistance of the alloy to plastic deformation by slip.

[STUDY OF PROTECTIVE ACTIVITY OF PROTEIN-CONTAINING ANTIGENS OF STREPTOCOCCUS PNEUMONIAE IN A HETEROLOGOUS SYSTEM].

PubMed

Vorobiev, D S; Semenova, I B; Volokh, Yu V; Romanenko, E E; Baturo, A P; Mikhailova, N A

2015-01-01

Study protective activity of protein-containing antigens of pneumococcus, obtained from serotypes 6B, 10A, 14, 19F, 23F and 36R, against infection with heterologous strains of S. pneumoniae. S. pneumoniae strains of serotypes 3, 6B, 10A, 14, 19F, 23F and 36R, obtained from the collection of pneumococcus strains of Mechnikov RIVS, were used in the study. Protein-containing antigens of S. pneumoniae were isolated by acetone precipitations of supernatant fraction of culture medium. Protective activity of preparations of protein-containing antigens of pneumococcus as studied in experiments of active protection of BALb/c line mice. The data obtained give evidence, that protein-containing antigens of pneumococcus, isolated from serotypes 6B, 10A, 14, 19F and 23F, effectively protect animals from subsequent infection with a heterologous S. pneumoniae strain of serotype 3 No. 11/56. Protection was noted at a level from 80 to 100% (p ≤ 0.05). Similar protective effect was detected in another experiment in a group of mice, immunized with preparations of protein-containing antigens of pneumococcus, obtained from serotypes 6B and 36R, against infection with a heterologous S. pneumoniae strain of serotype 3 No. 11/56. Protection was noted at a level of 90% (p ≤ 0.05). The results of the experiments carried out allow to assume, that the main role in formation of cross-protection in experiments in animals is played by pneumococcus, proteins, that are a part of the studied preparations, and not polysaccharide antigens.

Fetal myocardial deformation in maternal diabetes mellitus and obesity.

PubMed

Kulkarni, A; Li, L; Craft, M; Nanda, M; Lorenzo, J M M; Danford, D; Kutty, S

2017-05-01

Experimental evidence suggests that changes in the fetal myocardium result from intrauterine effects of maternal diabetes mellitus and obesity. The aim of this study was to assess fetal cardiac function using two-dimensional speckle-tracking echocardiography to determine the effects of maternal diabetes and obesity on the fetal myocardium. Comparative cross-sectional evaluation of myocardial function in fetuses of mothers with diabetes mellitus (FDM) or obesity (FO) and normal gestational age-matched control fetuses (FC) was performed using two-dimensional speckle-tracking echocardiography at two centers. In total, 178 fetuses (82 FDM, 26 FO and 70 FC) met the enrolment criteria. Mean gestational age at assessment was similar among groups: 25.3 ± 5.1 weeks for FDM, 25.0 ± 4.6 weeks for FO and 25.1 ± 4.9 weeks for FC. Mean maternal body mass index was significantly higher in FDM and FO groups compared with the FC group. Statistically significant differences in fetal cardiac function were detected between FDM and FC for global longitudinal strain (mean ± SD, -21.4 ± 6.5% vs -27.0 ± 5.2%; P < 0.001), global circumferential strain (mean ± SD, -22.6 ± 6.5% vs -26.2 ± 6.8%; P = 0.002), average longitudinal systolic strain rate (median, -1.4 (interquartile range (IQR), -1.7 to -1.1)/s vs -1.6 (IQR, -2.0 to -1.4)/s; P = 0.001) and average circumferential systolic strain rate (median, -1.4 (IQR, -1.9 to -1.1)/s vs -1.6 (IQR, -2.1 to -1.3)/s; P = 0.006). Cases of non-obese FDM also had abnormal strain parameters compared with FC. Global longitudinal strain (mean ± SD, -21.1 ± 7.5%) and average circumferential systolic strain rate (median, -1.3 (IQR, -1.8 to -1.1)/s) were significantly lower in FO compared with FC. Unfavorable changes occur in the fetal myocardium in response to both maternal diabetes mellitus and obesity. The long-term prognostic implications of these changes require further study. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Comparative antipneumococcal activities of sulopenem and other drugs.

PubMed

Kosowska-Shick, Klaudia; Ednie, Lois M; McGhee, Pamela; Appelbaum, Peter C

2009-06-01

For 297 penicillin-susceptible, -intermediate, and -resistant pneumococcal strains, the sulopenem MIC(50)s were 0.008, 0.06, and 0.25, respectively, and the sulopenem MIC(90)s were 0.016, 0.25, and 0.5 microg/ml, respectively. The MIC(50)s of amoxicillin for the corresponding strains were 0.03, 0.25, and 2.0 microg/ml, respectively, and the MIC(90)s were 0.03, 1.0, and 8.0 microg/ml, respectively. The combination of amoxicillin and clavulanate gave MICs similar to those obtained with amoxicillin alone. The sulopenem MICs were similar to those of imipenem and meropenem. The MICs of ss-lactams increased with those of penicillin G, and among the quinolones tested, moxifloxacin had the lowest MICs. Additionally, 45 strains of drug-resistant type 19A pneumococci were tested by agar dilution and gave sulopenem MIC(50)s and MIC(90)s of 1.0 and 2.0 microg/ml, respectively. Both sulopenem and amoxicillin (with and without clavulanate) were bactericidal against all 12 strains tested at 2x MIC after 24 h. Thirty-one strains from 10 countries with various penicillin, amoxicillin, and carbapenems MICs, including those with the highest sulopenem MICs, were selected for sequencing analysis of the pbp1a, pbp2x, and pbp2b regions encoding the transpeptidase active site and MurM. We did not find any correlations between specific penicillin-binding protein-MurM patterns and changes in the MICs.

Comparative Antipneumococcal Activities of Sulopenem and Other Drugs▿

PubMed Central

Kosowska-Shick, Klaudia; Ednie, Lois M.; McGhee, Pamela; Appelbaum, Peter C.

2009-01-01

For 297 penicillin-susceptible, -intermediate, and -resistant pneumococcal strains, the sulopenem MIC50s were 0.008, 0.06, and 0.25, respectively, and the sulopenem MIC90s were 0.016, 0.25, and 0.5 μg/ml, respectively. The MIC50s of amoxicillin for the corresponding strains were 0.03, 0.25, and 2.0 μg/ml, respectively, and the MIC90s were 0.03, 1.0, and 8.0 μg/ml, respectively. The combination of amoxicillin and clavulanate gave MICs similar to those obtained with amoxicillin alone. The sulopenem MICs were similar to those of imipenem and meropenem. The MICs of ß-lactams increased with those of penicillin G, and among the quinolones tested, moxifloxacin had the lowest MICs. Additionally, 45 strains of drug-resistant type 19A pneumococci were tested by agar dilution and gave sulopenem MIC50s and MIC90s of 1.0 and 2.0 μg/ml, respectively. Both sulopenem and amoxicillin (with and without clavulanate) were bactericidal against all 12 strains tested at 2× MIC after 24 h. Thirty-one strains from 10 countries with various penicillin, amoxicillin, and carbapenems MICs, including those with the highest sulopenem MICs, were selected for sequencing analysis of the pbp1a, pbp2x, and pbp2b regions encoding the transpeptidase active site and MurM. We did not find any correlations between specific penicillin-binding protein-MurM patterns and changes in the MICs. PMID:19307366

Nonomuraea glycinis sp. nov., a novel actinomycete isolated from the root of black soya bean [Glycine max (L.) Merr].

PubMed

Li, Zhilei; Song, Wei; Zhao, Junwei; Zhuang, Xiaoxin; Zhao, Yue; Wang, Xiangjing; Xiang, Wensheng

2017-12-01

A novel actinomycete, designated strain NEAU-BB2C19 T , was isolated from the root of black soya bean [Glycine max (L.) Merr] collected from Harbin, Heilongjiang Province, China, and characterized using a polyphasic approach. The strain was an aerobic, Gram-stain-positive actinomycete that formed extensively branched substrate mycelium and aerial hyphae. The predominant menaquinones were MK-9(H2) and MK-9(H0). The major cellular fatty acid profile consisted of iso-C16 : 0, 10-methyl C17 : 0 and 10-methyl C18 : 0. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, hydroxy-phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside, phosphatidylglycerol and glycolipid. The DNA G+C content was 68.2±0.4 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain NEAU-BB2C19 T should be assigned to the genus Nonomuraea and formed a distinct branch with its closest neighbour Nonomuraea guangzhouensis NEAU-ZJ3 T (98.75 % 16S rRNA gene sequence similarity). The morphological and chemotaxonomic properties of the strain were also consistent with those of members of the genus Nonomuraea. A combination of DNA-DNA hybridization results and some phenotypic characteristics indicated that strain NEAU-BB2C19 T could be clearly differentiated from its closest phylogenetic relative. Thus, the strain is concluded to represent a novel species of the genus Nonomuraea, for which the name Nonomuraea glycinis sp. nov. is proposed. The type strain is NEAU-BB2C19 T (=CGMCC 4.7430 T =DSM 104838 T ).

Taonella mepensis gen. nov., sp. nov., a member of the family Rhodospirillaceae isolated from activated sludge.

PubMed

Xi, Xue-dong; Dong, Wei-liang; Zhang, Jun; Huang, Yan; Cui, Zhong-li

2013-07-01

A novel Gram-negative, non-spore-forming, rod-shaped strain, H1(T), was isolated from activated sludge by micromanipulation. No close relatives among cultured bacterial isolates were found; phylogenetic analysis based on 16S rRNA gene sequences revealed that strain H1(T) forms a deep single branch in the family Rhodospirillaceae. Cells of strain H1(T) were slightly curved to straight rods (1.2-1.4 × 1.5-1.7 µm) and motile by a single polar flagellum. Strain H1(T) was able to grow in the presence of 0-4 % NaCl and grew optimally at 37 °C and pH 6.0-7.0. Chemotaxonomic analysis revealed that strain H1(T) possessed Q-10 as the predominant ubiquinone and C18 : 1ω7c, C16 : 0 and C19 : 0 cyclo ω8c as the major fatty acids. The DNA G+C content of strain H1(T) was 65.1 mol%. Comparative analysis of 16S rRNA gene sequences, and phenotypic and chemotaxonomic data, indicate that strain H1(T) should represent a novel genus and species of the family Rhodospirillaceae. The name Taonella mepensis gen. nov., sp. nov. is proposed. The type strain of Taonella mepensis is H1(T) ( = CICC 10529(T) = CCTCC AB 2012861(T) = KACC 16940(T)).

A Comparative Investigation of the use of Laminate-Level Meso-Scale and Fracture-Mechanics-Enriched Meso-Scale Composite-Material Models in Ballistic-Resistance Analyses

DTIC Science & Technology

2010-04-06

strain range (0.05, 0.5) Initial Velocity, m/s R es id ua lV el oc ity ,m /s 100 200 300 400 500 600 0 100 200 300 400 500 Laminate Scale Best Fit...DISTRIBUTION AVAILIBILITY STATEMENT Approved for public release; distribution is unlimited. UU 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS( ES ) 6...state during loading is determined by integrating the rate-form of the Hooke’s law in the form: rij ¼ Cijkl ekl; el ¼ Cijkl ekl ekl;p ; ð19Þ where

Variable Copy Number, Intra-Genomic Heterogeneities and Lateral Transfers of the 16S rRNA Gene in Pseudomonas

PubMed Central

Bodilis, Josselin; Nsigue-Meilo, Sandrine; Besaury, Ludovic; Quillet, Laurent

2012-01-01

Even though the 16S rRNA gene is the most commonly used taxonomic marker in microbial ecology, its poor resolution is still not fully understood at the intra-genus level. In this work, the number of rRNA gene operons, intra-genomic heterogeneities and lateral transfers were investigated at a fine-scale resolution, throughout the Pseudomonas genus. In addition to nineteen sequenced Pseudomonas strains, we determined the 16S rRNA copy number in four other Pseudomonas strains by Southern hybridization and Pulsed-Field Gel Electrophoresis, and studied the intra-genomic heterogeneities by Denaturing Gradient Gel Electrophoresis and sequencing. Although the variable copy number (from four to seven) seems to be correlated with the evolutionary distance, some close strains in the P. fluorescens lineage showed a different number of 16S rRNA genes, whereas all the strains in the P. aeruginosa lineage displayed the same number of genes (four copies). Further study of the intra-genomic heterogeneities revealed that most of the Pseudomonas strains (15 out of 19 strains) had at least two different 16S rRNA alleles. A great difference (5 or 19 nucleotides, essentially grouped near the V1 hypervariable region) was observed only in two sequenced strains. In one of our strains studied (MFY30 strain), we found a difference of 12 nucleotides (grouped in the V3 hypervariable region) between copies of the 16S rRNA gene. Finally, occurrence of partial lateral transfers of the 16S rRNA gene was further investigated in 1803 full-length sequences of Pseudomonas available in the databases. Remarkably, we found that the two most variable regions (the V1 and V3 hypervariable regions) had probably been laterally transferred from another evolutionary distant Pseudomonas strain for at least 48.3 and 41.6% of the 16S rRNA sequences, respectively. In conclusion, we strongly recommend removing these regions of the 16S rRNA gene during the intra-genus diversity studies. PMID:22545126

Intra-Genomic Heterogeneity in 16S rRNA Genes in Strictly Anaerobic Clinical Isolates from Periodontal Abscesses.

PubMed

Chen, Jiazhen; Miao, Xinyu; Xu, Meng; He, Junlin; Xie, Yi; Wu, Xingwen; Chen, Gang; Yu, Liying; Zhang, Wenhong

2015-01-01

Members of the genera Prevotella, Veillonella and Fusobacterium are the predominant culturable obligate anaerobic bacteria isolated from periodontal abscesses. When determining the cumulative number of clinical anaerobic isolates from periodontal abscesses, ambiguous or overlapping signals were frequently encountered in 16S rRNA gene sequencing chromatograms, resulting in ambiguous identifications. With the exception of the genus Veillonella, the high intra-chromosomal heterogeneity of rrs genes has not been reported. The 16S rRNA genes of 138 clinical, strictly anaerobic isolates and one reference strain were directly sequenced, and the chromatograms were carefully examined. Gene cloning was performed for 22 typical isolates with doublet sequencing signals for the 16S rRNA genes, and four copies of the rrs-ITS genes of 9 Prevotella intermedia isolates were separately amplified by PCR, sequenced and compared. Five conserved housekeeping genes, hsp60, recA, dnaJ, gyrB1 and rpoB from 89 clinical isolates of Prevotella were also amplified by PCR and sequenced for identification and phylogenetic analysis along with 18 Prevotella reference strains. Heterogeneity of 16S rRNA genes was apparent in clinical, strictly anaerobic oral bacteria, particularly in the genera Prevotella and Veillonella. One hundred out of 138 anaerobic strains (72%) had intragenomic nucleotide polymorphisms (SNPs) in multiple locations, and 13 strains (9.4%) had intragenomic insertions or deletions in the 16S rRNA gene. In the genera Prevotella and Veillonella, 75% (67/89) and 100% (19/19) of the strains had SNPs in the 16S rRNA gene, respectively. Gene cloning and separate amplifications of four copies of the rrs-ITS genes confirmed that 2 to 4 heterogeneous 16S rRNA copies existed. Sequence alignment of five housekeeping genes revealed that intra-species nucleotide similarities were very high in the genera Prevotella, ranging from 94.3-100%. However, the inter-species similarities were relatively low, ranging from 68.7-97.9%. The housekeeping genes rpoB and gyrB1 were demonstrated to be alternative classification markers to the species level based on intra- and inter-species comparisons, whereas based on phylogenetic tree rpoB proved to be reliable phylogenetic marker for the genus Prevotella.

Intra-Genomic Heterogeneity in 16S rRNA Genes in Strictly Anaerobic Clinical Isolates from Periodontal Abscesses

PubMed Central

Chen, Jiazhen; Miao, Xinyu; Xu, Meng; He, Junlin; Xie, Yi; Wu, Xingwen; Chen, Gang; Yu, Liying; Zhang, Wenhong

2015-01-01

Background Members of the genera Prevotella, Veillonella and Fusobacterium are the predominant culturable obligate anaerobic bacteria isolated from periodontal abscesses. When determining the cumulative number of clinical anaerobic isolates from periodontal abscesses, ambiguous or overlapping signals were frequently encountered in 16S rRNA gene sequencing chromatograms, resulting in ambiguous identifications. With the exception of the genus Veillonella, the high intra-chromosomal heterogeneity of rrs genes has not been reported. Methods The 16S rRNA genes of 138 clinical, strictly anaerobic isolates and one reference strain were directly sequenced, and the chromatograms were carefully examined. Gene cloning was performed for 22 typical isolates with doublet sequencing signals for the 16S rRNA genes, and four copies of the rrs-ITS genes of 9 Prevotella intermedia isolates were separately amplified by PCR, sequenced and compared. Five conserved housekeeping genes, hsp60, recA, dnaJ, gyrB1 and rpoB from 89 clinical isolates of Prevotella were also amplified by PCR and sequenced for identification and phylogenetic analysis along with 18 Prevotella reference strains. Results Heterogeneity of 16S rRNA genes was apparent in clinical, strictly anaerobic oral bacteria, particularly in the genera Prevotella and Veillonella. One hundred out of 138 anaerobic strains (72%) had intragenomic nucleotide polymorphisms (SNPs) in multiple locations, and 13 strains (9.4%) had intragenomic insertions or deletions in the 16S rRNA gene. In the genera Prevotella and Veillonella, 75% (67/89) and 100% (19/19) of the strains had SNPs in the 16S rRNA gene, respectively. Gene cloning and separate amplifications of four copies of the rrs-ITS genes confirmed that 2 to 4 heterogeneous 16S rRNA copies existed. Conclusion Sequence alignment of five housekeeping genes revealed that intra-species nucleotide similarities were very high in the genera Prevotella, ranging from 94.3–100%. However, the inter-species similarities were relatively low, ranging from 68.7–97.9%. The housekeeping genes rpoB and gyrB1 were demonstrated to be alternative classification markers to the species level based on intra- and inter-species comparisons, whereas based on phylogenetic tree rpoB proved to be reliable phylogenetic marker for the genus Prevotella. PMID:26103050

Identification of ssDNA aptamers specific to clinical isolates of Streptococcus mutans strains with different cariogenicity.

PubMed

Cui, Wei; Liu, Jiaojiao; Su, Donghua; Hu, Danyang; Hou, Shuai; Hu, Tongnan; Yang, Jiyong; Luo, Yanping; Xi, Qing; Chu, Bingfeng; Wang, Chenglong

2016-06-01

Streptococcus mutans, a Gram-positive facultative anaerobic bacterium, is considered to be a major etiological factor for dental caries. In this study, plaques from dental enamel surfaces of caries-active and caries-free individuals were obtained and cultivated for S. mutans isolation. Morphology examination, biochemical characterization, and polymerase chain reaction were performed to identify S. mutans The cariogenicity of S. mutans strains isolated from clinical specimens was evaluated by testing the acidogenicity, aciduricity, extracellular polysaccharide production, and adhesion ability of the bacteria. Finally, subtractive SELEX (systematic evolution of ligands by exponential enrichment) technology targeting whole intact cells was used to screen for ssDNA aptamers specific to the strains with high cariogenicity. After nine rounds of subtractive SELEX, sufficient pool enrichment was achieved as shown by radioactive isotope analysis. The enriched pool was cloned and sequenced randomly, followed by MEME online and RNA structure software analysis of the sequences. Results from the flow cytometry indicated that aptamers H1, H16, H4, L1, L10, and H19 could discriminate highly cariogenic S. mutans strains from poorly cariogenic strains. Among these, Aptamer H19 had the strongest binding capacity with cariogenic S. mutans strains with a dissociation constant of 69.45 ± 38.53 nM. In conclusion, ssDNA aptamers specific to highly cariogenic clinical S. mutans strains were successfully obtained. These ssDNA aptamers might be used for the early diagnosis and treatment of dental caries. © The Author 2016. Published by Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Impact of a protective vest and spacer garment on exercise-heat strain.

PubMed

Cheuvront, Samuel N; Goodman, Daniel A; Kenefick, Robert W; Montain, Scott J; Sawka, Michael N

2008-03-01

Protective vests worn by global security personnel, and weighted vests worn by athletes, may increase physiological strain due to added load, increased clothing insulation and vapor resistance. The impact of protective vest clothing properties on physiological strain, and the potential of a spacer garment to reduce physiological strain, was examined. Eleven men performed 3 trials of intermittent treadmill walking over 4 h in a hot, dry environment (35 degrees C, 30% rh). Volunteers wore the US Army battledress uniform (trial B), B + protective vest (trial P), and B + P + spacer garment (trial S). Biophysical clothing properties were determined and found similar to many law enforcement, industry, and sports ensembles. Physiological measurements included core (T (c)), mean skin (T (sk)) and chest (T (chest)) temperatures, heart rate (HR), and sweating rate (SR). The independent impact of clothing was determined by equating metabolic rate in all trials. In trial P, HR was +7 b/min higher after 1 h of exercise and +19 b/min by the fourth hour compared to B (P < 0.05). T (c) (+0.30 degrees C), T (sk) (+1.0 degrees C) and Physiological Strain Index were all higher in P than B (P < 0.05). S did not abate these effects except to reduce T (sk) (P > S) via a lower T (chest) (-0.40 degrees C) (P < 0.05). SR was higher (P < 0.05) in P and S versus B, but the magnitude of differences was small. A protective vest increases physiological strain independent of added load, while a spacer garment does not alter this outcome.

Diversity and Evolution of AbaR Genomic Resistance Islands in Acinetobacter baumannii Strains of European Clone I▿†

PubMed Central

Krizova, Lenka; Dijkshoorn, Lenie; Nemec, Alexandr

2011-01-01

To assess the diversity of AbaR genomic resistance islands in Acinetobacter baumannii European clone I (MLST clonal complex 1), we investigated 26 multidrug-resistant strains of this major clone isolated from hospitals in 21 cities of 10 European countries between 1984 and 2005. Each strain harbored an AbaR structure integrated at the same position in the chromosomal ATPase gene. AbaR3, including four subtypes based on variations in class 1 integron cassettes, and AbaR10 were found in 15 and 2 strains, respectively, whereas a new, unique AbaR variant was discovered in each of the other 9 strains. These new variants, designated AbaR11 to AbaR19 (19.8 kb to 57.5 kb), seem to be truncated derivatives of AbaR3, likely resulting from the deletions of its internal parts mediated by either IS26 elements (AbaR12 to AbaR19) or homologous recombination (AbaR11). AbaR3 was detected in all 10 strains isolated in 1984 to 1991, while AbaR11 to AbaR19 were carried only by strains isolated since 1997. Our results and those from previous publications suggest that AbaR3 is the original form of AbaR in European clone I, which may have provided strains of the lineage with a selective advantage facilitating their spread in European hospitals in the 1980s or before. PMID:21537009

Linezolid susceptibility in Helicobacter pylori, including strains with multidrug resistance.

PubMed

Boyanova, Lyudmila; Evstatiev, Ivailo; Gergova, Galina; Yaneva, Penka; Mitov, Ivan

2015-12-01

Only a few studies have evaluated Helicobacter pylori susceptibility to linezolid. The aim of the present study was to assess linezolid susceptibility in H. pylori, including strains with double/multidrug resistance. The susceptibility of 53 H. pylori strains was evaluated by Etest and a breakpoint susceptibility testing method. Helicobacter pylori resistance rates were as follows: amoxicillin, 1.9%; metronidazole, 37.7%; clarithromycin, 17.0%; tetracycline, 1.9%; levofloxacin, 24.5%; and linezolid (>4 mg/L), 39.6%. The linezolid MIC50 value was 31.2-fold higher than that of clarithromycin and 10.5-fold higher than that of levofloxacin; however, 4 of 11 strains with double/multidrug resistance were linezolid-susceptible. The MIC range of the oxazolidinone agent was larger (0.125-64 mg/L) compared with those in the previous two reports. The linezolid resistance rate was 2.2-fold higher in metronidazole-resistant strains and in strains resistant to at least one antibiotic compared with the remaining strains. Briefly, linezolid was less active against H. pylori compared with clarithromycin and levofloxacin, and linezolid resistance was linked to resistance to metronidazole as well as to resistance to at least one antibiotic. However, linezolid activity against some strains with double/multidrug resistance may render the agent appropriate to treat some associated H. pylori infections following in vitro susceptibility testing of the strains. Clinical trials are required to confirm this suggestion. Copyright © 2015 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Myocardial left ventricular dysfunction in patients with systemic lupus erythematosus: new insights from tissue Doppler and strain imaging.

PubMed

Buss, Sebastian J; Wolf, David; Korosoglou, Grigorios; Max, Regina; Weiss, Celine S; Fischer, Christian; Schellberg, Dieter; Zugck, Christian; Kuecherer, Helmut F; Lorenz, Hanns-Martin; Katus, Hugo A; Hardt, Stefan E; Hansen, Alexander

2010-01-01

Systemic lupus erythematosus (SLE) is associated with high cardiovascular morbidity and mortality. Cardiovascular involvement is frequently underestimated by routine imaging techniques. Our aim was to determine if new echocardiographic imaging modalities like tissue Doppler (TDI), strain rate (SRR), and strain (SRI) imaging detect abnormalities in left ventricular (LV) function in asymptomatic patients with SLE. Sixty-seven young patients with SLE (mean age 42 +/- 10 yrs) without typical symptoms or signs of heart failure or angina, and a matched healthy control group (n = 40), underwent standard transthoracic echocardiography, TDI, SRR, and SRI imaging of the LV as well as assessment of disease characteristics. Despite findings within the normal range on routine standard 2-dimensional echocardiography, SLE was associated with significantly impaired systolic and diastolic myocardial velocities of the LV measured by TDI [mean global TDI: systolic (s): 2.9 +/- 0.9 vs 3.9 +/- 0.7 cm/s, p < 0.05; early (e): 4.3 +/- 1.5 vs 6.3 +/- 1.3 cm/s, p < 0.05; late (a): 2.9 +/- 0.8 vs 3.4 +/- 0.8 cm/s, p < 0.05; values +/- SD); SRR (s: -0.8 +/- 0.1 vs -1.1 +/- 0.1 s(-1); e: 1.1 +/- 0.2 vs 1.6 +/- 0.3 s(-1); a: 0.7 +/- 0.1 vs 1.0 +/- 0.2 s(-1); all p < 0.05); and SR (-15.11 +/- 2.2% vs -19.7 +/- 1.9%; p < 0.05) compared to the control group. Further, elevated disease activity, measured with the ECLAM and the SLEDAI score, resulted in significantly lower values for LV longitudinal function measured by SRR and SR, but not by TDI. SLE is associated with a significant impairment of systolic and diastolic LV longitudinal function in patients without cardiac symptoms. New imaging modalities provide earlier insight into cardiovascular involvement in SLE and seem to be superior to standard echocardiography to detect subclinical myocardial disease.

Usefulness of right ventricular and right atrial two-dimensional speckle tracking strain to predict late arrhythmic events in adult patients with repaired Tetralogy of Fallot.

PubMed

Timóteo, Ana T; Branco, Luísa M; Rosa, Sílvia A; Ramos, Ruben; Agapito, Ana F; Sousa, Lídia; Galrinho, Ana; Oliveira, José A; Oliveira, Mário M; Ferreira, Rui C

2017-01-01

To determine whether right ventricular and/or atrial speckle tracking strain is associated with previous arrhythmic events in patients with repaired tetralogy of Fallot. We studied right ventricular and atrial strain in 100 consecutive patients with repaired tetralogy of Fallot referred for routine echocardiographic evaluation. Patients were divided into two groups, one with previous documentation of arrhythmias (n=26) and one without arrhythmias, in a median follow-up of 22 years. Patients with arrhythmias were older (p<0.001) and had surgical repair at an older age (p=0.001). They also had significantly reduced right ventricular strain (-14.7±5.5 vs. -16.9±4.0%, p=0.029) and right atrial strain (19.1±7.7% vs. 25.8±11.4%, p=0.001). Neither right ventricular nor right atrial strain were independent predictors of the presence of a history of documented arrhythmias, which was associated with age at correction and with the presence of residual defects. In a subanalysis after excluding 23 patients who had had more than one corrective surgery, right ventricular strain was an independent predictor of the presence of previous arrhythmic events (OR 1.19, 95% CI 1.02-1.38, p=0.025). Right atrial strain was also an independent predictor after adjustment (OR 0.93, 95% CI 0.87-0.99, p=0.029). The ideal cut-off for right ventricular strain was -15.3% and for right atrial strain 23.0%. Compared with conventional echocardiographic parameters, strain measures of the right heart are associated with the presence of arrhythmic events, and may be useful for risk stratification of patients with repaired tetralogy of Fallot, although a prospective study is required. Copyright © 2016 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

The Eukaryote-Like Serine/Threonine Kinase STK Regulates the Growth and Metabolism of Zoonotic Streptococcus suis

PubMed Central

Zhang, Chunyan; Sun, Wen; Tan, Meifang; Dong, Mengmeng; Liu, Wanquan; Gao, Ting; Li, Lu; Xu, Zhuofei; Zhou, Rui

2017-01-01

Like eukaryotes, bacteria express one or more serine/threonine kinases (STKs) that initiate diverse signaling networks. The STK from Streptococcus suis is encoded by a single-copy stk gene, which is crucial in stress response and virulence. To further understand the regulatory mechanism of STK in S. suis, a stk deletion strain (Δstk) and its complementary strain (CΔstk) were constructed to systematically decode STK characteristics by applying whole transcriptome RNA sequencing (RNA-Seq) and phosphoproteomic analysis. Numerous genes were differentially expressed in Δstk compared with the wild-type parental strain SC-19, including 320 up-regulated and 219 down-regulated genes. Particularly, 32 virulence-associated genes (VAGs) were significantly down-regulated in Δstk. Seven metabolic pathways relevant to bacterial central metabolism and translation are significantly repressed in Δstk. Phosphoproteomic analysis further identified 12 phosphoproteins that exhibit differential phosphorylation in Δstk. These proteins are associated with cell growth and division, glycolysis, and translation. Consistently, phenotypic assays confirmed that the Δstk strain displayed deficient growth and attenuated pathogenicity. Thus, STK is a central regulator that plays an important role in cell growth and division, as well as S. suis metabolism. PMID:28326294

Phenotypic characterization of Leishmania spp. causing cutaneous leishmaniasis in the lower Amazon region, western Pará state, Brazil, reveals a putative hybrid parasite, Leishmania (Viannia) guyanensis × Leishmania (Viannia) shawi shawi

PubMed Central

Jennings, Yara Lins; de Souza, Adelson Alcimar Almeida; Ishikawa, Edna Aoba; Shaw, Jeffrey; Lainson, Ralph; Silveira, Fernando

2014-01-01

We phenotypically characterized 43 leishmanial parasites from cutaneous leishmaniasis by isoenzyme electrophoresis and the indirect immunofluorescence antibody test (23 McAbs). Identifications revealed 11 (25.6%) strains of Leishmania (V.) braziliensis, 4 (9.3%) of L. (V.) shawi shawi, 7 (16.3%) of L. (V.) shawi santarensis, 6 (13.9%) of L. (V.) guyanensis and L. (V.) lainsoni, 2 (4.7%) of L. (L.) amazonensis, and 7 (16.3%) of a putative hybrid parasite, L. (V.) guyanensis/L. (V.) shawi shawi. McAbs detected three different serodemes of L. (V.) braziliensis: I-7, II-1, and III-3 strains. Among the strains of L. (V.) shawi we identified two populations: one (7 strains) expressing the B19 epitope that was previously considered to be species-specific for L. (V.) guyanensis. We have given this population sub-specific rank, naming it L. (V.) s. santarensis. The other one (4 strains) did not express the B19 epitope like the L. (V.) shawi reference strain, which we now designate as L. (V.) s. shawi. For the first time in the eastern Brazilian Amazon we register a putative hybrid parasite (7 strains), L. (V.) guyanensis/L. (V.) s. shawi, characterized by a new 6PGDH three-band profile at the level of L. (V.) guyanensis. Its PGM profile, however, was very similar to that of L. (V.) s. shawi. These results suggest that the lower Amazon region – western Pará state, Brazil, represents a biome where L. (V.) guyanensis and L. (V.) s. shawi exchange genetic information. PMID:25083790

Fontibacillus aquaticus gen. nov., sp. nov., isolated from a warm spring.

PubMed

Saha, P; Krishnamurthi, S; Bhattacharya, A; Sharma, R; Chakrabarti, T

2010-02-01

A novel facultatively anaerobic strain, designated GPTSA 19(T), was isolated from a warm spring and characterized using a polyphasic approach. The strain behaved as Gram-negative in the Gram staining procedure but showed a Gram-positive reaction in the aminopeptidase test. The novel strain was a mesophilic rod with ellipsoidal endospores. On the basis of 16S rRNA gene sequence analysis, the strain showed closest similarity (96.0 %) with Paenibacillus motobuensis MC10(T). The gene sequence similarity of the novel strain with other species of the genus Paenibacillus was <95.8 %. The novel strain also had PAEN 515F and 682F signature sequence stretches in the 16S rRNA gene that are usually found in most species of the genus Paenibacillus. The strain possessed anteiso-C(15 : 0) as the major fatty acid and MK-7 as the predominant menaquinone. Polar lipids included diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), six unknown phospholipids (PLs), one aminophospholipid (PN), three glycolipids (GLs), two aminolipids (ALs), one aminophosphoglycolipid (APGL) and three unknown lipids (ULs). The polar lipid profile of the novel strain, especially as regards ALs, GLs and PLs, distinguished it from the recognized type species of the genus Paenibacillus, Paenibacillus polymyxa, as well as from its closest relative P. motobuensis. Based on phenotypic and chemotaxonomic characteristics and analysis of the 16S rRNA gene sequence, the new strain merits the rank of a novel genus for which the name Fontibacillus gen. nov. is proposed. The type species of the new genus is Fontibacillus aquaticus gen. nov., sp. nov. with the type strain GPTSA 19(T) (=MTCC 7155(T)=DSM 17643(T)).

Antimosquito property of Petroselinum crispum (Umbellifereae) against the pyrethroid resistant and susceptible strains of Aedes aegypti (Diptera: Culicidae).

PubMed

Intirach, J; Junkum, A; Lumjuan, N; Chaithong, U; Jitpakdi, A; Riyong, D; Wannasan, A; Champakaew, D; Muangmoon, R; Chansang, A; Pitasawat, B

2016-12-01

The increasing and widespread resistance to conventional synthetic insecticides in vector populations has underscored the urgent need to establish alternatives in the mosquito management system. This study was carried out with the aim to investigate the antimosquito property, larvicidal and adulticidal potential, of plant products against both the pyrethroid-susceptible and resistant strains of Aedes aegypti. Seventeen plant products, including essential oils and ethanolic extracts, were obtained by steam distillation and extraction with 95 % ethanol, respectively. Their larvicidal activity was screened, using World Health Organization (WHO) procedures against A. aegypti, Muang Chiang Mai-susceptible (MCM-S) strain. The most effective product was a candidate for investigating larvicidal and adulticidal potential against three laboratory strains of A. aegypti, comprising MCM-S, Pang Mai Dang-resistant (PMD-R), and Upakut-resistant (UPK-R). Potential toxicity of the plant candidate was compared with that of synthetic temephos, permethrin, and deltamethrin. Chemical constituents of the most effective plant product also were analyzed by gas chromatography-mass spectrometry (GC-MS). Results obtained from the preliminary screening revealed the varying larvicidal efficacy of plant-derived products against MCM-S A. aegypti, with mortality ranging from 0 to 100 %. The larvicidal activity of seven effective plant products was found to be dose dependent, with the highest efficacy established from Petroselinum crispum fruit oil, followed by oils of Foeniculum vulgare, Myristica fragrans, Limnophila aromatica, Piper sarmentosum, Curcuma longa, and M. fragrans ethanolic extract (LC 50 values of 43.22, 44.84, 47.42, 47.94, 49.19, 65.51, and 75.45 ppm, respectively). Essential oil of P. crispum was then investigated further and proved to be a promising larvicide and adulticide against all strains of A. aegypti. The pyrethroid-resistant strains of both PMD-R and UPK-R A. aegypti showed significant resistance to temephos, permethrin, and deltamethrin in either the larval or adult stage. Interestingly, high susceptibility to P. crispum oil was observed in the larvae and adults of MCM-S, which are pyrethroid-susceptible A. aegypti, and comparable to those of the pyrethroid-resistant strains, PMD-R and UPK-R. GC-MS analysis of P. crispum oil demonstrated that 19 compounds, accounting for 98.25 % of the whole oil, were identified, with the main constituents being thymol (42.41 %), p-cymene (27.71 %), and γ-terpinene (20.98 %). In conclusion, the profound larvicidal and adulticidal potential of P. crispum oil promises to form a new larvicide and adulticide against either the pyrethroid-susceptible or resistant strain of A. aegypti. Consequently, P. crispum oil and its constituents can be used or incorporated with other chemicals/measures in integrated mosquito management for controlling A. aegypti, particularly in localities with high levels of pyrethroid and organophosphate resistance.

Nationwide German Multicenter Study on the Prevalence of Antibiotic Resistance in Streptococcal Blood Isolates from Neutropenic Patients and Comparative In Vitro Activities of Quinupristin-Dalfopristin and Eight Other Antimicrobials

PubMed Central

Reinert, Ralf René; von Eiff, Christof; Kresken, Michael; Brauers, Johannes; Hafner, Dieter; Al-Lahham, Adnan; Schorn, Holger; Lütticken, Rudolf; Peters, Georg

2001-01-01

In a prospective multicenter study (1996 to 1999), 156 episodes of bacteremic streptococcal infections of neutropenic patients were evaluated. Streptococcus oralis (26.3%), S. pneumoniae (26.3%), S. agalactiae (11.5%), S. mitis (9%), and S. pyogenes (5.8%) were the predominant species. Four strains (2.6%) were found to be intermediately resistant to penicillin. One strain (0.6%) was found to be highly resistant to penicillin (MIC, 8 mg/liter). Reduced susceptibility to penicillin was detected among S. oralis (14.6%), S. mitis (7.1%), and S. pneumoniae (4.9%) isolates but was not recorded among S. agalactiae and S. pyogenes. Resistance rates and intermediate resistance rates for other antimicrobials were as follows (all species): amoxicillin, 1.3 and 3.2%; erythromycin, 16 and 2.6%; clindamycin, 5.8 and 0%; ciprofloxacin, 1.9 and 7.7%. Quinupristin-dalfopristin showed good in vitro activity against most streptococcal isolates (MIC at which 50% of the isolates were inhibited [MIC50], 0.5 mg/liter; MIC90, 1 mg/liter, MIC range, 0.25 to 4 mg/liter). PMID:11326015

Molecular diversity, cultivation, and improved detection by fluorescent in situ hybridization of a dominant group of human gut bacteria related to Roseburia spp. or Eubacterium rectale.

PubMed

Aminov, Rustam I; Walker, Alan W; Duncan, Sylvia H; Harmsen, Hermie J M; Welling, Gjalt W; Flint, Harry J

2006-09-01

Phylogenetic analysis was used to compare 16S rRNA sequences from 19 cultured human gut strains of Roseburia and Eubacterium rectale with 356 related sequences derived from clone libraries. The cultured strains were found to represent five of the six phylotypes identified. A new oligonucleotide probe, Rrec584, and the previous group probe Rint623, when used in conjunction with a new helper oligonucleotide, each recognized an average of 7% of bacteria detected by the eubacterial probe Eub338 in feces from 10 healthy volunteers. Most of the diversity within this important group of butyrate-producing gut bacteria can apparently be retrieved through cultivation.

Molecular Diversity, Cultivation, and Improved Detection by Fluorescent In Situ Hybridization of a Dominant Group of Human Gut Bacteria Related to Roseburia spp. or Eubacterium rectale

PubMed Central

Aminov, Rustam I.; Walker, Alan W.; Duncan, Sylvia H.; Harmsen, Hermie J. M.; Welling, Gjalt W.; Flint, Harry J.

2006-01-01

Phylogenetic analysis was used to compare 16S rRNA sequences from 19 cultured human gut strains of Roseburia and Eubacterium rectale with 356 related sequences derived from clone libraries. The cultured strains were found to represent five of the six phylotypes identified. A new oligonucleotide probe, Rrec584, and the previous group probe Rint623, when used in conjunction with a new helper oligonucleotide, each recognized an average of 7% of bacteria detected by the eubacterial probe Eub338 in feces from 10 healthy volunteers. Most of the diversity within this important group of butyrate-producing gut bacteria can apparently be retrieved through cultivation. PMID:16957265

Streptomyces pini sp. nov., an actinomycete isolated from phylloplane of pine (Pinus sylvestris L.) needle-like leaves.

PubMed

Madhaiyan, Munusamy; Poonguzhali, Selvaraj; Saravanan, Venkatakrishnan Sivaraj; Duraipandiyan, Veeramuthu; Al-Dhabi, Naif Abdullah; Pragatheswari, Dhandapani; Santhanakrishnan, Palani; Kim, Soo-Jin; Weon, Hang-Yeon; Kwon, Soon-Wo

2016-10-01

A novel siderophore-producing actinomycete, designated PL19T, was isolated from the Scots-pine needle-like leaves collected from TNAU campus, Coimbatore, India. The isolate was chemoorganotrophic in nutrition and able to grow at 30 °C, and the optimum pH and NaCl facilitated the growth pH 6-11 and 0-8 % (w/v), respectively. The cells are filamentous and the mycelia formed are basically of wide and intricately branched substrate mycelium from which aerial mycelia arises, later gets differentiated into spores that are warty and arranged spirally. The 16S rRNA gene of strain PL19T was sequenced and was highly similar to the type strains of species of the genus Streptomyces, including Streptomyces barkulensis RC1831T (98.8 % pairwise similarity), Streptomyces fenghuangensis GIMN4.003T (98.2 %), Streptomyces nanhaiensis SCSIO 01248T (98.0 %), Streptomyces radiopugnans R97T (97.9 %), Streptomyces atacamensis C60T (97.8 %) and Streptomyces macrosporus NBRC 14749T (97.2 %), all of which were subjected to taxonomical characterization using a polyphasic approach. The strains showed unique carbon utilization patterns, and it possesses iso-C16 : 0 anteiso-C15 : 0 and anteiso-C17 : 0 as a major cellular fatty acids. The cell-wall was dominated with ll-type diaminopimelic acid, and the menaquinone type was MK-9(H6, H8). These chemotaxonomic evidences placed strain PL19T within the genus Streptomyces. The determination of G+C ratio (69.5 mol%) and DNA-DNA hybridization values (13.4-31.8 % with the phylogenetically related species) helped in further hierarchical classification of strain PL19T. Based on morphological, physiological and chemotaxonomic data as well as DNA-DNA hybridization values, strain PL19T could be distinguished from the evolutionarily closest species currently available. All these collective data show that strain PL19T represents a novel species of the genus Streptomyces, for which the name Streptomyces pini sp. nov. is proposed. The type strain is PL19T (=NRRL B-24728T=ICMP 17783T).

Characterization of putative virulence factors of Serratia marcescens strain SEN for pathogenesis in Spodoptera litura.

PubMed

Aggarwal, Chetana; Paul, Sangeeta; Tripathi, Vishwas; Paul, Bishwajeet; Khan, Md Aslam

2017-02-01

Two Serratia marcescens strains, SEN and ICC-4, isolated from diseased insect cadavers were observed to differ considerably in their virulence towards Spodoptera litura. The present study was aimed to characterize the possible virulence factors present in the virulent Serratia marcescens strain SEN. Both the S. marcescens strains were evaluated for the presence of various lytic enzymes such as chitinase, lipase, protease and phospholipase. The virulent S. marcescens strain SEN was observed to possess considerably higher activity of chitinase and protease enzymes; activity of phospholipase enzyme was also higher. Although, all the three toxin genes shlA, phlA and swr could be detected in both the S. marcescens strains, there was a higher expression of these genes in the virulent strain SEN. S. marcescens strain ICC-4 showed greater reduction in overall growth yield in the post-exponential phase in the presence of midgut juice and hemolymph of S. litura larvae, as compared to S. marcescens strain SEN. Proliferation of the S. marcescens strain SEN was also considerably higher in foregut, midgut and hemolymph of S. litura larvae, as compared to strain ICC-4. Peritrophic membrane treated with broth culture of the S. marcescens strain SEN showed higher damage as compared to strain ICC-4. The peritrophic membrane of larvae fed on diet treated with the virulent strain showed considerable damage while the peritrophic membrane of larvae fed on diet treated with the non-virulent strain showed no damage. This is the first report documenting the fate of ingested S. marcescens in S. litura gut and the relative expression of toxin genes from two S. marcescens strains differing in their virulence towards S. litura. Copyright © 2016 Elsevier Inc. All rights reserved.

19-VNTR loci used in genotyping Chinese clinical Mycobacterium tuberculosis complex strains and in association with spoligotyping.

PubMed

Jiang, Yi; Liu, Hai-can; Zheng, Huajun; Dou, Xiangfeng; Tang, Biao; Zhao, Xiu-qin; Zhu, Yongqiang; Lu, Bing; Wang, Shengyue; Dong, Hai-yan; Zhang, Yuan-yuan; Zhao, Guoping; Wan, Kanglin

2013-07-01

Recently, tandem repeat typing has emerged as a rapid and easy method for the molecular epidemiology of the Mycobacterium tuberculosis (M. tuberculosis) complex. In this study, a collection of 19 VNTRs incorporating 15 previously described loci and 4 newly evaluated markers were used to genotype 206 Chinese M. tuberculosis isolates and 9 BCG strains. The discriminatory power was evaluated and compared with that obtained by Spoligotyping. It turned out that 15-locus VNTR could be very useful in M. tuberculosis complex strains genotyping in China. The 4 newly evaluated loci were proved informative and could be useful for future epidemiology studies, especially in Beijing family strains. In addition, a unique pattern of the latter 4 loci were found in Chinese BCG strains. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Self-accommodation of B19' martensite in Ti-Ni shape memory alloys - Part II. Characteristic interface structures between habit plane variants

NASA Astrophysics Data System (ADS)

Nishida, M.; Okunishi, E.; Nishiura, T.; Kawano, H.; Inamura, T.; S., Ii; Hara, T.

2012-06-01

Four characteristic interface microstructures between habit plane variants (HPVs) in the self-accommodation morphologies of B19‧ martensite in Ti-Ni alloys have been investigated by scanning transmission electron microscopy (STEM). The straight interface of a ? B19‧ type I twin is present at interface I. The relaxation of the transformation strain at interface II is achieved by a volume reduction of the minor correspondence variants (CVs) in the relevant habit plane variants (HPVs). The relaxation of the transformation strain at interface III is mainly due to the formation of a ? B19‧ type I twin between the two major CVs. Subsequently, local strain around the tips of the minor CVs perpendicular to the interface is released by the formation of micro-twins with the ⟨011⟩B19‧ type II and/or ? B19‧ type I relation. The major and minor CVs in each HPV are alternately connected through fine variants with the ? B19‧ type I twin relation parallel to interface IV. The results are compared with macroscopic observations and the predictions of PTMC analysis.

Vector Development for the Expression of Foreign Proteins in the Vaccine Strain Brucella abortus S19

PubMed Central

Comerci, Diego J.; Pollevick, Guido D.; Vigliocco, Ana M.; Frasch, Alberto C. C.; Ugalde, Rodolfo A.

1998-01-01

A vector for the expression of foreign antigens in the vaccine strain Brucella abortus S19 was developed by using a DNA fragment containing the regulatory sequences and the signal peptide of the Brucella bcsp31 gene. This fragment was cloned in broad-host-range plasmid pBBR4MCS, resulting in plasmid pBEV. As a reporter protein, a repetitive antigen of Trypanosoma cruzi was used. The recombinant fusion protein is stably expressed and secreted into the Brucella periplasmic space, inducing a good antibody response against the T. cruzi antigen. The expression of the repetitive antigen in Brucella neither altered its growth pattern nor generated a toxic or lethal effect during experimental infection. The application of this strategy for the generation of live recombinant vaccines and the tagging of B. abortus S19 vaccine is discussed. This is the first time that a recombinant protein has been expressed in the periplasm of brucellae. PMID:9673273

Automated Description of Regional Left Ventricular Motion in Patients With Cardiac Amyloidosis: A Quantitative Study Using Heart Deformation Analysis.

PubMed

Meng, Leng; Lin, Kai; Collins, Jeremy; Markl, Michael; Carr, James C

2017-08-01

The purpose of this article is to test the hypothesis that heart deformation analysis can automatically quantify regional myocardial motion patterns in patients with cardiac amyloidosis. Eleven patients with cardiac amyloidosis and 11 healthy control subjects were recruited to undergo cardiac MRI. Cine images were analyzed using heart deformation analysis and feature tracking. Heart deformation analysis-derived myocardial motion indexes in radial and circumferential directions, including radial and circumferential displacement, radial and circumferential velocity, radial and circumferential strain, and radial and circumferential strain rate, were compared between the two groups. The heart deformation analysis tool required a shorter mean (± SD) processing time than did the feature-tracking tool (1.5 ± 0.3 vs 5.1 ± 1.2 minutes). Patients with cardiac amyloidosis had lower peak radial displacement (4.32 ± 1.37 vs 5.62 ± 1.19 mm), radial velocity (25.50 ± 7.70 vs 33.41 ± 5.43 mm/s), radial strain (23.32% ± 10.24% vs 31.21% ± 8.71%), circumferential strain (-13.44% ± 4.21% vs -17.84% ± 2.84%), radial strain rate (1.14 ± 0.46 vs 1.58 ± 0.41 s -1 ), and circumferential strain rate (-0.78 ± 0.22 vs -1.08 ± 0.20 s -1 ) than did healthy control subjects. Heart deformation analysis-derived indexes correlated with feature tracking-derived indexes (r = 0.411 and 0.552). Heart deformation analysis is able to automatically quantify regional myocardial motion in patients with cardiac amyloidosis without the need for operator interaction.

Genotypes of macrolide-resistant pneumococci from children in southwestern Japan: raised incidence of strains that have both erm(B) and mef(A) with serotype 6B clones.

PubMed

Ikenaga, Masaaki; Kosowska-Shick, Klaudia; Gotoh, Kenji; Hidaka, Hidenobu; Koga, Hiroyasu; Masunaga, Kenji; Nagai, Kensuke; Tsumura, Naoki; Appelbaum, Peter C; Matsuishi, Toyojiro

2008-09-01

MICs of penicillin G, erythromycin, clarithromycin, clindamycin, azithromycin, and telithromycin were tested for 189 clinical isolates collected during 2002 to 2005 from children in southwestern Japan. Serotyping and polymerase chain reaction for presence of erm(B) and mef(A) were performed. All strains with erm(B) + mef(A) were analyzed by pulsed-field gel electrophoresis (PFGE) and compared to 3 global clones: Spain(23F)-1; Spain(9V)-3 and its variant -14; a South Korean strain same as Taiwan (19F)-14 clone and 5 strains with erm(B) + mef(A) from other countries. Of the 173 macrolide-resistant (erythromycin MIC > or =0.5 microg/mL) strains, 104 (60.1%) had erm(B), 47 (27.2%) had mef(A), and 22 (12.7%) had erm(B) + mef(A). Strains expressing erm(B) or both erm(B) and mef(A) had high macrolide MIC(90)s (>64 microg/mL), except telithromycin (MIC(90), 0.25 microg/mL). Of the 22 erm(B) + mef(A) strains, 10 had 4 distinct PFGE patterns and were mainly serotype 6B clones, which differed from those described in previous reports; 5 other strains had unique profiles.

Analysis of infant isolates of Bifidobacterium breve by comparative genome hybridization indicates the existence of new subspecies with marked infant specificity.

PubMed

Boesten, Rolf; Schuren, Frank; Wind, Richèle D; Knol, Jan; de Vos, Willem M

2011-09-01

A total of 20 Bifidobacterium strains were isolated from fecal samples of 4 breast- and bottle-fed infants and all were characterized as Bifidobacterium breve based on 16S rRNA gene sequence and metabolic analysis. These isolates were further characterized and compared to the type strains of B. breve and 7 other Bifidobacterium spp. by comparative genome hybridization. For this purpose, we constructed and used a DNA-based microarray containing over 2000 randomly cloned DNA fragments from B. breve type strain LMG13208. This molecular analysis revealed a high degree of genomic variation between the isolated strains and allowed the vast majority to be grouped into 4 clusters. One cluster contained a single isolate that was virtually indistinguishable from the B. breve type strain. The 3 other clusters included 19 B. breve strains that differed considerably from all type strains. Remarkably, each of the 4 clusters included strains that were isolated from a single infant, indicating that a niche adaptation may contribute to variation within the B. breve species. Based on genomic hybridization data, the new B. breve isolates were estimated to contain approximately 60-90% of the genes of the B. breve type strain, attesting to the existence of various subspecies within the species B. breve. Further bioinformatic analysis identified several hundred diagnostic clones specific to the genomic clustering of the B. breve isolates. Molecular analysis of representatives of these revealed that annotated genes from the conserved B. breve core encoded mainly housekeeping functions, while the strain-specific genes were predicted to code for functions related to life style, such as carbohydrate metabolism and transport. This is compatible with genetic adaptation of the strains to their niche, a combination of infants and diet. Copyright © 2011 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Role of B19' martensite deformation in stabilizing two-way shape memory behavior in NiTi

DOE PAGES

Benafan, O.; Padula, S. A.; Noebe, R. D.; ...

2012-11-01

Deformation of a B19' martensitic, polycrystallineNi49.9Ti50.1 (at. %) shape memoryalloy and its influence on the magnitude and stability of the ensuing two-way shape memory effect (TWSME) was investigated by combined ex situ mechanical experimentation and in situneutron diffraction measurements at stress and temperature. The microstructural changes (texture, lattice strains, and phase fractions) during room-temperature deformation and subsequent thermal cycling were captured and compared to the bulk macroscopic response of the alloy. With increasing uniaxial strain, it was observed that B19' martensite deformed by reorientation and detwinning with preferred selection of the (1¯50) M and (010) M variants, (201¯) B19' deformationmore » twinning, and dislocation activity. These mechanisms were indicated by changes in bulk texture from the neutron diffraction measurements. Partial reversibility of the reoriented variants and deformation twins was also captured upon load removal and thermal cycling, which after isothermal deformation to strains between 6% and 22% resulted in a strong TWSME. Consequently, TWSME functional parameters including TWSME strain, strain reduction, and transformation temperatures were characterized and it was found that prior martensite deformation to 14% strain provided the optimum condition for the TWSME, resulting in a stable two-way shape memory strain of 2.2%. Thus, isothermal deformation of martensite was found to be a quick and efficient method for creating a strong and stable TWSME in Ni₄₉.₉Ti₅₀.₁.« less

Cryptic nature of a conserved, CD4-inducible V3 loop neutralization epitope in the native envelope glycoprotein oligomer of CCR5-restricted, but not CXCR4-using, primary human immunodeficiency virus type 1 strains.

PubMed

Lusso, Paolo; Earl, Patricia L; Sironi, Francesca; Santoro, Fabio; Ripamonti, Chiara; Scarlatti, Gabriella; Longhi, Renato; Berger, Edward A; Burastero, Samuele E

2005-06-01

The external subunit of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env), gp120, contains conserved regions that mediate sequential interactions with two cellular receptor molecules, CD4 and a chemokine receptor, most commonly CCR5 or CXCR4. However, antibody accessibility to such regions is hindered by diverse protective mechanisms, including shielding by variable loops, conformational flexibility and extensive glycosylation. For the conserved neutralization epitopes hitherto described, antibody accessibility is reportedly unrelated to the viral coreceptor usage phenotype. Here, we characterize a novel, conserved gp120 neutralization epitope, recognized by a murine monoclonal antibody (MAb), D19, which is differentially accessible in the native HIV-1 Env according to its coreceptor specificity. The D19 epitope is contained within the third variable (V3) domain of gp120 and is distinct from those recognized by other V3-specific MAbs. To study the reactivity of MAb D19 with the native oligomeric Env, we generated a panel of PM1 cells persistently infected with diverse primary HIV-1 strains. The D19 epitope was conserved in the majority (23/29; 79.3%) of the subtype-B strains tested, as well as in selected strains from other genetic subtypes. Strikingly, in CCR5-restricted (R5) isolates, the D19 epitope was invariably cryptic, although it could be exposed by addition of soluble CD4 (sCD4); epitope masking was dependent on the native oligomeric structure of Env, since it was not observed with the corresponding monomeric gp120 molecules. By contrast, in CXCR4-using strains (X4 and R5X4), the epitope was constitutively accessible. In accordance with these results, R5 isolates were resistant to neutralization by MAb D19, becoming sensitive only upon addition of sCD4, whereas CXCR4-using isolates were neutralized regardless of the presence of sCD4. Other V3 epitopes examined did not display a similar divergence in accessibility based on coreceptor usage phenotype. These results provide the first evidence of a correlation between HIV-1 biological phenotype and neutralization sensitivity, raising the possibility that the in vivo evolution of HIV-1 coreceptor usage may be influenced by the selective pressure of specific host antibodies.

The autoinducer synthase LqsA and putative sensor kinase LqsS regulate phagocyte interactions, extracellular filaments and a genomic island of Legionella pneumophila.

PubMed

Tiaden, André; Spirig, Thomas; Sahr, Tobias; Wälti, Martin A; Boucke, Karin; Buchrieser, Carmen; Hilbi, Hubert

2010-05-01

The amoebae-resistant opportunistic pathogen Legionella pneumophila employs a biphasic life cycle to replicate in host cells and spread to new niches. Upon entering the stationary growth phase, the bacteria switch to a transmissive (virulent) state, which involves a complex regulatory network including the lqs gene cluster (lqsA-lqsR-hdeD-lqsS). LqsR is a putative response regulator that promotes host-pathogen interactions and represses replication. The autoinducer synthase LqsA catalyses the production of the diffusible signalling molecule 3-hydroxypentadecan-4-one (LAI-1) that is presumably recognized by the sensor kinase LqsS. Here, we analysed L. pneumophila strains lacking lqsA or lqsS. Compared with wild-type L. pneumophila, the DeltalqsS strain was more salt-resistant and impaired for the Icm/Dot type IV secretion system-dependent uptake by phagocytes. Legionella pneumophila strains lacking lqsS, lqsR or the alternative sigma factor rpoS sedimented more slowly and produced extracellular filaments. Deletion of lqsA moderately reduced the uptake of L. pneumophila by phagocytes, and the defect was complemented by expressing lqsA in trans. Unexpectedly, the overexpression of lqsA also restored the virulence defect and reduced filament production of L. pneumophila mutant strains lacking lqsS or lqsR, but not the phenotypes of strains lacking rpoS or icmT. These results suggest that LqsA products also signal through sensors not encoded by the lqs gene cluster. A transcriptome analysis of the DeltalqsA and DeltalqsS mutant strains revealed that under the conditions tested, lqsA regulated only few genes, whereas lqsS upregulated the expression of 93 genes at least twofold. These include 52 genes clustered in a 133 kb high plasticity genomic island, which is flanked by putative DNA-mobilizing genes and encodes multiple metal ion efflux pumps. Upon overexpression of lqsA, a cluster of 19 genes in the genomic island was also upregulated, suggesting that LqsA and LqsS participate in the same regulatory circuit.

Pedobacter lusitanus sp. nov., isolated from sludge of a deactivated uranium mine.

PubMed

Covas, Cláudia; Caetano, Tânia; Cruz, Andreia; Santos, Tiago; Dias, Liliana; Klein, Guenter; Abdulmawjood, Amir; Rodríguez-Alcalá, Luis M; Pimentel, Lígia L; Gomes, Ana; Freitas, Ana Cristina; Garcia-Serrano, Alba; Fontecha, Javier; Mendo, Sónia

2017-05-01

Strain NL19T is a Gram-stain-negative, aerobic bacterium that was isolated from sludge of a deactivated uranium mine in Portugal. 16S rRNA gene sequence analysis revealed that strain NL19T is a member of the genus Pedobacter and closely related to the strains Pedobacter himalayensis MTCC 6384T, Pedobacter cryoconitis DSM 14825T, Pedobacter westerhofensis DSM 19036T and Pedobacterhartonius DSM 19033T. It had a DNA G+C content of 40.8 mol%, which agreed with the genus description. The main fatty acids included C16 : 1ω7c, C14 : 1ω5c, C4 : 0, iso-C17 : 0, iso-C17 : 0 3-OH, C16 : 0, anteiso-C15 : 0 and iso-C15 : 0 3-OH. The main lipids present were phospholipids (60 %) and sphingolipids (35 %). The most abundant phospholipids included phosphatidylethanolamine, phosphatidylinositol and phosphatidylcholine. Menaquinone-7 (MK-7) was the only isoprenoid quinone detected. DNA-DNA hybridization similarities between strain NL19T and Pedobacter himalayensis MTCC 6384T, Pedobacter cryoconitis DSM 14825T, Pedobacter westerhofensis DSM 19036T and Pedobacter hartonius DSM 19033T were 15.3 , 16.2 , 11.5 and 16.0 %, respectively. Strain NL19T can also be distinguished from these four species based on gyrB and intergenic transcribed spacers (ITS) sequences and by some phenotypic traits such as NaCl tolerance, pH, growth temperature and carbon source utilization. Strain NL19Trepresents a novel species of the genus Pedobacter, for which the name Pedobacter lusitanus sp. nov. is proposed. The type strain is NL19T (=LMG 29220T=CECT 9028T). An amended description of Pedobacter himalayensis is also included.

Genetic Diversity of the fliC Genes Encoding the Flagellar Antigen H19 of Escherichia coli and Application to the Specific Identification of Enterohemorrhagic E. coli O121:H19.

PubMed

Beutin, Lothar; Delannoy, Sabine; Fach, Patrick

2015-06-15

Enterohemorrhagic Escherichia coli (EHEC) O121:H19 belong to a specific clonal type distinct from other classical EHEC and major enteropathogenic E. coli groups and is regarded as one of the major EHEC serogroups involved in severe infections in humans. Sequencing of the fliC genes associated with the flagellar antigen H19 (fliCH19) revealed the genetic diversity of the fliCH19 gene sequences in E. coli. A cluster analysis of 12 fliCH19 sequences, 4 from O121 and 8 from non-O121 E. coli strains, revealed five different genotypes. All O121:H19 strains fell into one cluster, whereas a second cluster was formed by five non-O121:H19 strains. Cluster 1 and cluster 2 strains differ by 27 single nucleotide exchanges in their fliCH19 genes (98.5% homology). Based on allele discrimination of the fliCH19 genes, a real-time PCR test was designed for specific identification of EHEC O121:H19. The O121 fliCH19 PCR tested negative in 73 E. coli H19 strains that belonged to serogroups other than O121, including 28 different O groups, O-nontypeable H19, and O-rough:H19 strains. The O121 fliCH19 PCR reacted with all 16 tested O121:H19 strains and 1 O-rough:H19 strain which was positive for the O121 wzx gene. A cross-reaction was observed only with E. coli H32 strains which share sequence similarities in the target region of the O121 fliCH19 PCR. The combined use of O-antigen genotyping (O121 wzx) and the detection of O121 fliCH19 allele type contributes to improving the identification and molecular serotyping of EHEC O121:H19 motile and nonmotile strains and variants of these strains lacking stx genes. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Genetic Diversity of the fliC Genes Encoding the Flagellar Antigen H19 of Escherichia coli and Application to the Specific Identification of Enterohemorrhagic E. coli O121:H19

PubMed Central

Beutin, Lothar; Delannoy, Sabine

2015-01-01

Enterohemorrhagic Escherichia coli (EHEC) O121:H19 belong to a specific clonal type distinct from other classical EHEC and major enteropathogenic E. coli groups and is regarded as one of the major EHEC serogroups involved in severe infections in humans. Sequencing of the fliC genes associated with the flagellar antigen H19 (fliCH19) revealed the genetic diversity of the fliCH19 gene sequences in E. coli. A cluster analysis of 12 fliCH19 sequences, 4 from O121 and 8 from non-O121 E. coli strains, revealed five different genotypes. All O121:H19 strains fell into one cluster, whereas a second cluster was formed by five non-O121:H19 strains. Cluster 1 and cluster 2 strains differ by 27 single nucleotide exchanges in their fliCH19 genes (98.5% homology). Based on allele discrimination of the fliCH19 genes, a real-time PCR test was designed for specific identification of EHEC O121:H19. The O121 fliCH19 PCR tested negative in 73 E. coli H19 strains that belonged to serogroups other than O121, including 28 different O groups, O-nontypeable H19, and O-rough:H19 strains. The O121 fliCH19 PCR reacted with all 16 tested O121:H19 strains and 1 O-rough:H19 strain which was positive for the O121 wzx gene. A cross-reaction was observed only with E. coli H32 strains which share sequence similarities in the target region of the O121 fliCH19 PCR. The combined use of O-antigen genotyping (O121 wzx) and the detection of O121 fliCH19 allele type contributes to improving the identification and molecular serotyping of EHEC O121:H19 motile and nonmotile strains and variants of these strains lacking stx genes. PMID:25862232

Tensile and Microindentation Stress-Strain Curves of Al-6061

DOE Data Explorer

Weaver, Jordan S [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Center for Integrated Nanotechnologies (CINT); Khosravani, Ali [Georgia Inst. of Technology, Atlanta, GA (United States); Castillo, Andrew [Georgia Inst. of Technology, Atlanta, GA (United States); Kalidind, Surya R [Georgia Inst. of Technology, Atlanta, GA (United States)

2016-07-13

Recent spherical microindentation stress-strain protocols were developed and validated on Al-6061 (DOI: 10.1186/s40192-016-0054-3). The scaling factor between the uniaxial yield strength and the indentation yield strength was determined to be about 1.9. The microindentation stress-strain protocols were then applied to a microstructurally graded sample in an effort to extract high throughput process-property relationships. The tensile and microindentation force-displacement and stress-strain data are presented in this data set.

In Vivo-Selected Compensatory Mutations Restore the Fitness Cost of Mosaic penA Alleles That Confer Ceftriaxone Resistance in Neisseria gonorrhoeae.

PubMed

Vincent, Leah R; Kerr, Samuel R; Tan, Yang; Tomberg, Joshua; Raterman, Erica L; Dunning Hotopp, Julie C; Unemo, Magnus; Nicholas, Robert A; Jerse, Ann E

2018-04-03

Resistance to ceftriaxone in Neisseria gonorrhoeae is mainly conferred by mosaic penA alleles that encode penicillin-binding protein 2 (PBP2) variants with markedly lower rates of acylation by ceftriaxone. To assess the impact of these mosaic penA alleles on gonococcal fitness, we introduced the mosaic penA alleles from two ceftriaxone-resistant (Cro r ) clinical isolates (H041 and F89) into a Cro s strain (FA19) by allelic exchange and showed that the resultant Cro r mutants were significantly outcompeted by the Cro s parent strain in vitro and in a murine infection model. Four Cro r compensatory mutants of FA19 penA41 were isolated independently from mice that outcompeted the parent strain both in vitro and in vivo One of these compensatory mutants (LV41C) displayed a unique growth profile, with rapid log growth followed by a sharp plateau/gradual decline at stationary phase. Genome sequencing of LV41C revealed a mutation (G348D) in the acnB gene encoding the bifunctional aconitate hydratase 2/2 methylisocitrate dehydratase. Introduction of the acnB G348D allele into FA19 penA41 conferred both a growth profile that phenocopied that of LV41C and a fitness advantage, although not as strongly as that exhibited by the original compensatory mutant, suggesting the existence of additional compensatory mutations. The mutant aconitase appears to be a functional knockout with lower activity and expression than wild-type aconitase. Transcriptome sequencing (RNA-seq) analysis of FA19 penA41 acnB G348D revealed a large set of upregulated genes involved in carbon and energy metabolism. We conclude that compensatory mutations can be selected in Cro r gonococcal strains that increase metabolism to ameliorate their fitness deficit. IMPORTANCE The emergence of ceftriaxone-resistant (Cro r ) Neisseria gonorrhoeae has led to the looming threat of untreatable gonorrhea. Whether Cro resistance is likely to spread can be predicted from studies that compare the relative fitnesses of susceptible and resistant strains that differ only in the penA gene that confers Cro resistance. We showed that mosaic penA alleles found in Cro r clinical isolates are outcompeted by the Cro s parent strain in vitro and in vivo but that compensatory mutations that allow ceftriaxone resistance to be maintained by increasing bacterial fitness are selected during mouse infection. One compensatory mutant that was studied in more detail had a mutation in acnB , which encodes the aconitase that functions in the tricarboxylic acid (TCA) cycle. This study illustrates that compensatory mutations can be selected during infection, which we hypothesize may allow the spread of Cro resistance in nature. This study also provides novel insights into gonococcal metabolism and physiology.

Antimicrobial properties of lactic acid bacteria isolated from traditional yogurt and milk against Shigella strains.

PubMed

Zare Mirzaei, Elnaze; Lashani, Elahe; Davoodabadi, Abolfazl

2018-01-01

Background: Lactic acid bacteria (LAB) are normal flora of the mouth, intestines and the female genital tract. They are also frequently found in meat, vegetables, and dairy products. Most of probiotic bacteria belong to the LAB group. Some probiotic LAB are useful in prevention and treatment of diarrheal diseases. The aim of this study was to investigate the antimicrobial properties of LAB isolated from traditional yogurt and milk against Shigella strains. Materials and methods: Forty LAB strains were isolated from traditional yogurt and milk. The antimicrobial activity of LAB against Shigella strains (eight S. flexneri , four S. sonnei ) was examined using the agar-well diffusion assay. LAB strains with antimicrobial effect against all Shigella strains were identified by 16S rRNA gene sequencing. Results: Six LAB strains inhibited the growth of all 12 Shigella strains. Lb. paracasei Y1-3, Lb. paracasei Y8-1 and Lb. fermentum Y2-2 were isolated from yogurt. Lb. paracasei M18-1, Lb. parelimentarius M4-3 and Lb. plantarum M19-1 were isolated from milk. Conclusion: This study showed that Lactobacillus strains with good inhibitory activity against S. flexneri and S. sonnei could be isolated from traditional yogurt and milk.

Isolation and characterization of bacteria capable of degrading polycyclic aromatic hydrocarbons (PAHs) and organophosphorus pesticides from PAH-contaminated soil in Hilo, Hawaii.

PubMed

Seo, Jong-Su; Keum, Young-Soo; Harada, Renee M; Li, Qing X

2007-07-11

Nineteen bacterial strains were isolated from petroleum-contaminated soil in Hilo, HI, and characterized by two different spray-plated methods, turbidity test in liquid medium, and 16S rRNA gene sequence analysis. Analysis of the soil showed 13 polycyclic aromatic hydrocarbons (PAHs) in a range from 0.6 to 30 mg/kg of dry weight each and 12 PAH metabolites. Five distinct bacterial strains (C3, C4, P1-1, JS14, and JS19b1) selected from preliminary plating and turbidity tests were further tested for PAH degradation through single PAH degradation assay. Strains C3, C4, and P1-1 degraded phenanthrene (40 mg/L) completely during 7 days of incubation. Strain JS14 degraded fluoranthene (40 mg/L) completely during 10 days of incubation. Strain JS19b1 degraded 100% of phenanthrene (40 mg/L) in 7 days, 77% of fluorene (40 mg/L) in 14 days, 97% of fluoranthene (40 mg/L) in 10 days, and 100% of pyrene (40 mg/L) in 14 days. Turbidity tests showed that strains P1-1, JS14, and JS19b1 utilized several organophosphorus pesticides as growth substrate. P1-1 can degrade carbofenothion, chlorfenvinphos, diazinon, fonofos, and pirimiphos-methyl. JS14 can transform chlorfenvinphos and diazinon. JS19b1 can break down diazinon, pirimiphos-methyl, and temephos.

Genetic analysis of the VP2-encoding gene of canine parvovirus strains from Africa.

PubMed

Dogonyaro, Banenat B; Bosman, Anna-Mari; Sibeko, Kgomotso P; Venter, Estelle H; van Vuuren, Moritz

2013-08-30

Since the emergence of canine parvovirus type-2 (CPV-2) in the early 1970s, it has been evolving into novel genetic and antigenic variants (CPV-2a, 2b and 2c) that are unevenly distributed throughout the world. Genetic characterization of CPV-2 has not been documented in Africa since 1998 apart from the study carried out in Tunisia 2009. A total of 139 field samples were collected from South Africa and Nigeria, detected using PCR and the full length VP2-encoding gene of 27 positive samples were sequenced and genetically analyzed. Nigerian samples (n=6), South Africa (n=19) and vaccine strains (n=2) were compared with existing sequences obtained from GenBank. The results showed the presence of both CPV-2a and 2b in South Africa and only CPV-2a in Nigeria. No CPV-2c strain was detected during this study. Phylogenetic analysis showed a clustering not strictly associated with the geographical origin of the analyzed strains, although most of the South African strains tended to cluster together and the viral strains analyzed in this study were not completely distinct from CPV-2 strains from other parts of the world. Amino acid analysis showed predicted amino acid changes. Copyright © 2013 Elsevier B.V. All rights reserved.

Low-phosphate-selected Auxenochlorella protothecoides redirects phosphate to essential pathways while producing more biomass

PubMed Central

Park, Sang-Hyuck; Kyndt, John; Chougule, Kapeel; Park, Jeong-Jin

2018-01-01

Despite the capacity to accumulate ~70% w/w of lipids, commercially produced unicellular green alga A. protothecoides may become compromised due to the high cost of phosphate fertilizers. To address this limitation A. protothecoides was selected for adaptation to conditions of 100× and 5× lower phosphate and peptone, respectively, compared to ‘wild-type media’. The A. protothecoides showed initial signs of adaptation by 45–50 days, and steady state growth at ~100 days. The low phosphate (P)-adapted strain produced up to ~30% greater biomass, while total lipids (~10% w/w) remained about the same, compared to the wild-type strain. Metabolomic analyses indicated that the low P-adapted produced 3.3-fold more saturated palmitic acid (16:0) and 2.2-fold less linolenic acid (18:3), compared to the wild-type strain, resulting in an ~11% increase in caloric value, from 19.5kJ/g for the wild-type strain to 21.6kJ/g for the low P-adapted strain, due to the amounts and composition of certain saturated fatty acids, compared to the wild type strain. Biochemical changes in A. protothecoides adapted to lower phosphate conditions were assessed by comparative RNA-Seq analysis, which yielded 27,279 transcripts. Among them, 2,667 and 15 genes were significantly down- and up-regulated, at >999-fold and >3-fold (adjusted p-value <0.1), respectively. The expression of genes encoding proteins involved in cellular processes such as division, growth, and membrane biosynthesis, showed a trend toward down-regulation. At the genomic level, synonymous SNPs and Indels were observed primarily in coding regions, with the 40S ribosomal subunit gene harboring substantial SNPs. Overall, the adapted strain out-performed the wild-type strain by prioritizing the use of its limited phosphate supply for essential biological processes. The low P-adapted A. protothecoides is expected to be more economical to grow over the wild-type strain, based on overall greater productivity and caloric content, while importantly, also requiring 100-fold less phosphate. PMID:29920531

An Experimental Study of Large Compressive Loads Upon Residual Strain Fields and the Interaction Between Surface Strain Fields Created by Coldworking Fastener Holes.

DTIC Science & Technology

1981-02-01

Strains" (J. of Basic Eng., Vol. 82, Series D, June 1960), pp, 426-434. 10. Morse, S., A.J. Durelli, and C.A. Sciammarella , "Geo- metry of Moire...grid Method, a Practical Moire Stress-analysis Tool" (Exp. Mech., Vol. 7, July 1967), pp. 19A-22A. 20. Sciammarella , C., "Moire-fringe Multiplication

Left Atrial Strain at Different Stages of Myxomatous Mitral Valve Disease in Dogs.

PubMed

Nakamura, K; Kawamoto, S; Osuga, T; Morita, T; Sasaki, N; Morishita, K; Ohta, H; Takiguchi, M

2017-03-01

Decreased function of the left atrium (LA) is a useful prognostic indicator in dogs with myxomatous mitral valve disease (MMVD). In humans, LA strain is a novel severity indicator of mitral regurgitation, but its clinical utility in dogs has not been confirmed. To examine whether LA strain as evaluated with speckle-tracking echocardiography is associated with MMVD stage in dogs. Fifty-two client-owned dogs with MMVD. Cross-sectional study. Dogs were classified as stage B1, B2, C, or D, according to the American College of Veterinary Internal Medicine consensus. Physical examination findings and echocardiographic variables were compared among the groups. To assess the comparative accuracy of echocardiographic variables in identifying dogs with the presence or history congestive heart failure (CHF), receiver operating characteristic curves and multivariate logistic analysis were used. There were no significant differences in parameters of LA strain between B1 and B2 groups. However, LA longitudinal strain during atrial contraction (ε A ) (median, 19.1%; interquartile range, 15.3-24.3% in B1, 19.6%; 14.1-21.4% in B2, 6.2%; 3.18-11.2% in C/D) and during ventricular systole (ε S ) (32.7%; 28.9-39.2% in B1, 35.6%; 31.7-41.9% in B2, 23.6%; 16.9-26.1% in C/D) were significantly lower in stages C/D than in stages B1 and B2. In multivariate logistic regression analysis, ε A and peak early diastolic mitral inflow velocity were identified as independent indicators of stage C/D. ε A was the best predictor of the presence or history of CHF. Further studies are needed to determine the clinical implications of these findings for treatment decisions and prognosis determination. Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Water tubing-related injuries treated in US emergency departments, 1991-2009.

PubMed

Heinsimer, Kevin R; Nelson, Nicolas G; Roberts, Kristin J; McKenzie, Lara B

2013-02-01

The objective was to describe the patterns and mechanisms of water tubing-related injuries treated in U.S. emergency departments. The National Electronic Injury Surveillance System was used to examine cases of water tubing-related injuries. Sample weights were used to calculate national estimates of water tubing-related injuries. Analyses were conducted in 2010. From 1991-2009 an estimated 69,471 injuries were treated in US emergency departments for water tubing-related injuries. The annual number of cases increased 250% over the 19-year study period (P < .001). Sprains and strains accounted for the largest portion of injuries (27.2%). The head was the most frequently injured body part (27.5%). Children and adolescents ≤ 19 years were more likely to be injured by contact with another person (OR: 2.47; 95% CI = 1.61-3.80) and were more likely to sustain injuries to the head (OR: 2.61; 95% CI = 2.01-3.38) compared with adults. Adults ≥ 20 years, were more likely than individuals ≤ 19 years to sustain sprains and strains (OR: 2.11; 95% CI = 1.64-2.71) and were most commonly injured by impact with the water (54.6%). Patterns of water tubing-related injuries differ for children and adults. Research is needed to determine how best to reduce these injuries.

Bromomethylthioindole Inspired Carbazole Hybrids as Promising Class of Anti-MRSA Agents.

PubMed

Cheng, Chia-Yi; Chang, Chun-Ping; Lauderdale, Tsai-Ling Yang; Yu, Guann-Yi; Lee, Jinq-Chyi; Jhang, Yi-Wun; Wu, Chien-Huang; Ke, Yi-Yu; Sadani, Amit A; Yeh, Ching-Fang; Huang, I-Wen; Kuo, Yi-Ping; Tsai, De-Jiun; Yeh, Teng-Kuang; Tseng, Chen-Tso; Song, Jen-Shin; Liu, Yu-Wei; Tsou, Lun K; Shia, Kak-Shan

2016-12-08

Series of N -substituted carbazole analogues bearing an indole ring were synthesized as anti-methicillin-resistant Staphylococcus aureus (MRSA) agents from a molecular hybridization approach. The representative compound 19 showed an MIC = 1 μg/mL against a panel of MRSA clinical isolates as it possessed comparable in vitro activities to that of vancomycin. Moreover, compound 19 also exhibited MIC = 1 μg/mL activities against a recent identified Z172 MRSA strain (vancomycin-intermediate and daptomycin-nonsusceptible phenotype) and the vancomycin-resistant Enterococcus faecalis (VRE) strain. In a mouse model with lethal infection of MRSA (4N216), a 75% survival rate was observed after a single dose of compound 19 was intravenously administered at 20 mg/kg. In light of their equipotent activities against different MRSA isolates and VRE strain, the data underscore the importance of designed hybrid series for the development of new N -substituted carbazoles as potential anti-MRSA agents.

Assessment of Culturable Tea Rhizobacteria Isolated from Tea Estates of Assam, India for Growth Promotion in Commercial Tea Cultivars

PubMed Central

Dutta, Jintu; Handique, Pratap J.; Thakur, Debajit

2015-01-01

In the present study, 217 rhizobacterial isolates were obtained from six different tea estates of Assam, India and subjected to preliminary in vitro plant growth promotion (PGP) screening for indole acetic acid (IAA) production, phosphate solubilization, siderophore production and ammonia production. Fifty isolates showed all the PGP traits and five isolates did not exhibit any PGP traits. These 50 potential isolates were further analyzed for quantitative estimation of the PGP traits along with the aminocyclopropane-1-carboxylate (ACC) deaminase, protease and cellulose production. After several rounds of screening, four rhizobacteria were selected based on their maximum ability to produce in vitro PGP traits and their partial 16S rRNA gene sequence analysis revealed that they belong to Enterobacter lignolyticus strain TG1, Burkholderia sp. stain TT6, Bacillus pseudomycoides strain SN29 and Pseudomonas aeruginosa strain KH45. To evaluate the efficacy of these four rhizobacteria as plant growth promoters, three different commercially important tea clones TV1, TV19, and TV20 plants were inoculated with these rhizobacteria in greenhouse condition and compared to the uninoculated control plants. Though, all the rhizobacterial treatments showed an increase in plant growth compared to control but the multivariate PCA analysis confirmed more growth promotion by TG1 and SN29 strains than the other treatments in all three clones. To validate this result, the fold change analysis was performed and it revealed that the tea clone TV19 plants inoculated with the E. lignolyticus strain TG1 showed maximum root biomass production with an increase in 4.3-fold, shoot biomass with increase in 3.1-fold, root length by 2.2-fold and shoot length by 1.6-fold. Moreover, two way ANOVA analysis also revealed that rhizobacterial treatment in different tea clones showed the significant increase (P < 0.05) in growth promotion compared to the control. Thus, this study indicates that the potential of these indigenous plant growth promoting rhizobacteria isolates to use as microbial inoculation or biofertilizer for growth promotion of tea crops. PMID:26617590

Youth versus adult "weightlifting" injuries presenting to United States emergency rooms: accidental versus nonaccidental injury mechanisms.

PubMed

Myer, Gregory D; Quatman, Carmen E; Khoury, Jane; Wall, Eric J; Hewett, Timothy E

2009-10-01

Resistance training has previously been purported to be unsafe and ineffective in children. The purpose of this investigation was to evaluate resistance training-related injuries presenting to U.S. emergency rooms by age, type, and mechanism of injury. We hypothesized that older athletes would sustain greater percentages of joint sprains and muscle strains, whereas younger athletes would sustain a greater percentage of accidental injuries that would result in an increased percentage of fractures in youths. The U.S. Consumer Product Safety Commission (CPSC) National Electronic Injury Surveillance System was queried from 2002 to 2005 using the CPSC code for "Weightlifting." Subjects between the ages of 8 and 30 were grouped by age categories 8 to 13 (elementary/middle school age), 14 to 18 (high school), 19 to 22 (college), and 23 to 30 (adult). Injuries were classified as "accidental" if caused by dropped weight or improper equipment use. Multiple logistic regression was used to compare accidental injuries between age groups. The sample consisted of 4,111 patients. Accidental injuries decreased (p < 0.05) with age: 8 to 13 > 14 to 18 > 19 to 22 years = 23 to 30 years. Conversely, sprain/strain injuries increased in each successive age group (p < 0.05). Evaluation of only the nonaccidental injuries (n = 2,565) showed that the oldest categories (19-22 and 23-30 yr) demonstrated a greater percentage of sprains and strains relative to younger age categories (p < 0.001). Two thirds of the injuries sustained in the 8 to 13 group were to the hand and foot and were most often related to "dropping" and "pinching" in the injury descriptions, and there was an increased percentage of fractures in the 8 to 13 group relative to all other groups (p < 0.001). The study findings indicate that children have lower risk of resistance training-related joint sprains and muscle strains than adults. The majority of youth resistance training injuries are the result of accidents that are potentially preventable with increased supervision and stricter safety guidelines.

Detection of Rare G3P[19] Porcine Rotavirus Strains in Chiang Mai, Thailand, Provides Evidence for Origin of the VP4 Genes of Mc323 and Mc345 Human Rotaviruses▿

PubMed Central

Maneekarn, Niwat; Khamrin, Pattara; Chan-it, Wisoot; Peerakome, Supatra; Sukchai, Sujin; Pringprao, Kidsadagon; Ushijima, Hiroshi

2006-01-01

Among 175 fecal specimens collected from diarrheic piglets during a surveillance of porcine rotavirus (PoRV) strains in Chiang Mai, Thailand, 39 (22.3%) were positive for group A rotaviruses. Of these, 33.3% (13 of 39) belonged to G3P[19], which was a rare P genotype seldom reported. Interestingly, their VP4 nucleotide sequences were most closely related to human P[19] strains (Mc323 and Mc345) isolated in 1989 from the same geographical area where these PoRV strains were isolated. These P[19] PoRV strains were also closely related to another human P[19] strain (RMC321), isolated from India in 1990. The VP4 sequence identities with human P[19] were 95.4% to 97.4%, while those to a porcine P[19] strain (4F) were only 87.6 to 89.1%. Phylogenetic analysis of the VP4 gene revealed that PoRV P[19] strains clustered with human P[19] strains in a monophyletic branch separated from strain 4F. Analysis of the VP7 gene confirmed that these strains belonged to the G3 genotype and shared 97.7% to 98.3% nucleotide identities with other G3 PoRV strains circulating in the regions. This close genetic relationship was also reflected in the phylogenetic analysis of their VP7 genes. Altogether, the findings provided peculiar evidence that supported the porcine origin of VP4 genes of Mc323 and Mc345 human rotaviruses. PMID:16988014

Impact of Compounding Error on Strategies for Subtyping Pathogenic Bacteria

PubMed Central

Orfe, Lisa; Davis, Margaret A.; Lafrentz, Stacey; Kang, Min-Su

2008-01-01

Abstract Comparative-omics will identify a multitude of markers that can be used for intraspecific discrimination between strains of bacteria. It seems intuitive that with this plethora of markers we can construct higher resolution subtyping assays using discrete markers to define strain “barcodes.” Unfortunately, with each new marker added to an assay, overall assay robustness declines because errors are compounded exponentially. For example, the difference in accuracy of strain classification for an assay with 60 markers will change from 99.9% to 54.7% when average probe accuracy declines from 99.999% to 99.0%. To illustrate this effect empirically, we constructed a 19 probe bead-array for subtyping Listeria monocytogenes and showed that despite seemingly reliable individual probe accuracy (>97%), our best classification results at the strain level were <75%. A more robust strategy would use as few markers as possible to achieve strain discrimination. Consequently, we developed two variable number of tandem repeat (VNTR) assays (Vibrio parahaemolyticus and L. monocytogenes) and demonstrate that these assays along with a published assay (Salmonella enterica) produce robust results when products were machine scored. The discriminatory ability with four to seven VNTR loci was comparable to pulsed-field gel electrophoresis. Passage experiments showed some instability with ca. 5% of passaged lines showing evidence for new alleles within 30 days (V. parahaemolyticus and S. enterica). Changes were limited to a single locus and allele so conservative rules can be used to determine strain matching. Most importantly, VNTRs appear robust and portable and can clearly discriminate between strains with relatively few loci thereby limiting effects of compounding error. PMID:18713065

Genome Sequence of Saccharomyces carlsbergensis, the World’s First Pure Culture Lager Yeast

PubMed Central

Walther, Andrea; Hesselbart, Ana; Wendland, Jürgen

2014-01-01

Lager yeast beer production was revolutionized by the introduction of pure culture strains. The first established lager yeast strain is known as the bottom fermenting Saccharomyces carlsbergensis, which was originally termed Unterhefe No. 1 by Emil Chr. Hansen and has been used in production in since 1883. S. carlsbergensis belongs to group I/Saaz-type lager yeast strains and is better adapted to cold growth conditions than group II/Frohberg-type lager yeasts, e.g., the Weihenstephan strain WS34/70. Here, we sequenced S. carlsbergensis using next generation sequencing technologies. Lager yeasts are descendants from hybrids formed between a S. cerevisiae parent and a parent similar to S. eubayanus. Accordingly, the S. carlsbergensis 19.5-Mb genome is substantially larger than the 12-Mb S. cerevisiae genome. Based on the sequence scaffolds, synteny to the S. cerevisae genome, and by using directed polymerase chain reaction for gap closure, we generated a chromosomal map of S. carlsbergensis consisting of 29 unique chromosomes. We present evidence for genome and chromosome evolution within S. carlsbergensis via chromosome loss and loss of heterozygosity specifically of parts derived from the S. cerevisiae parent. Based on our sequence data and via fluorescence-activated cell-sorting analysis, we determined the ploidy of S. carlsbergensis. This inferred that this strain is basically triploid with a diploid S. eubayanus and haploid S. cerevisiae genome content. In contrast the Weihenstephan strain, which we resequenced, is essentially tetraploid composed of two diploid S. cerevisiae and S. eubayanus genomes. Based on conserved translocations between the parental genomes in S. carlsbergensis and the Weihenstephan strain we propose a joint evolutionary ancestry for lager yeast strains. PMID:24578374

Bartonella apis sp. nov., a honey bee gut symbiont of the class Alphaproteobacteria.

PubMed

Kešnerová, Lucie; Moritz, Roxane; Engel, Philipp

2016-01-01

Here, we report the culture and characterization of an alphaproteobacterium of the order Rhizobiales, isolated from the gut of the honey bee Apis mellifera. Strain PEB0122T shares >95 % 16S rRNA gene sequence similarity with species of the genus Bartonella, a group of mammalian pathogens transmitted by bloodsucking arthropods. Phylogenetic analyses showed that PEB0122T and related strains from the honey bee gut form a sister clade of the genus Bartonella. Optimal growth of strain PEB0122T was obtained on solid media supplemented with defibrinated sheep blood under microaerophilic conditions at 35-37 °C, which is consistent with the cultural characteristics of other species of the genus Bartonella. Reduced growth of strain PEB0122T also occurred under aerobic conditions. The rod-shaped cells of strain PEB0122T had a mean length of 1.2-1.8 μm and revealed hairy surface structures. Strain PEB0122T was positive for catalase, cytochrome c oxidase, urease and nitrate reductase. The fatty acid composition was comparable to those of other species of the genus Bartonella, with palmitic acid (C16 : 0) and isomers of 18- and 19-carbon chains being the most abundant. The genomic DNA G+C content of PEB0122T was determined to be about 45.5 mol%. The high 16S rRNA gene sequence similarity with species of Bartonella and its close phylogenetic position suggest that strain PEB0122T represents a novel species within the genus Bartonella, for which we propose the name Bartonella apis sp. nov. The type strain is PEB0122T ( = NCIMB 14961T = DSM 29779T).

[Selection of acetate-tolerant mutants from Escherichia coli DH5alpha and the metabolic properties of mutant DA19].

PubMed

Zhu, Caiqing; Ye, Qin

2003-08-01

Esherichia coli DH5alpha is one of the widely used host strains in genetic engineering. However, foreign gene expression level in this strain is seriously inhibited due to its great sensitivity to the accumulated metabolite, acetate. This study aimed at improving the tolerance of this strain against acetate. Cells of E. coli DH5alpha were irradiated with 60Co, and subsequently continuous culture of the irradiated cells was conducted with gradual increase in the dilution rate and the selective pressure, acetate concentration in the medium. The mutants were picked up on MA plates which contained 5g/L sodium acetate. 5 strains with great improvement in acetate tolerance were obtained, among which DA19 was the best. In cultivation of DA19 in complex media YPS and YPS2G, the cell density, maximum specific growth rate and acetate produced were respectively 1.17 and 1.05, 1.08 and 1.27, and 0.06 and 0.59 times of those of DH5alpha. In a chemically defined medium, the cell density of DA19 was 3.4-fold of that of DH5alpha. The cell density of DA19 in a medium containing 10g/L sodium acetate was comparable to that of DH5alpha in the same medium without the addition of acetate.

The Shigella human challenge model.

PubMed

Porter, C K; Thura, N; Ranallo, R T; Riddle, M S

2013-02-01

Shigella is an important bacterial cause of infectious diarrhoea globally. The Shigella human challenge model has been used since 1946 for a variety of objectives including understanding disease pathogenesis, human immune responses and allowing for an early assessment of vaccine efficacy. A systematic review of the literature regarding experimental shigellosis in human subjects was conducted. Summative estimates were calculated by strain and dose. While a total of 19 studies evaluating nine strains at doses ranging from 10 to 1 × 1010 colony-forming units were identified, most studies utilized the S. sonnei strain 53G and the S. flexneri strain 2457T. Inoculum solution and pre-inoculation buffering has varied over time although diarrhoea attack rates do not appear to increase above 75-80%, and dysentery rates remain fairly constant, highlighting the need for additional dose-ranging studies. Expansion of the model to include additional strains from different serotypes will elucidate serotype and strain-specific outcome variability.

Lactobacillus ixorae sp. nov., isolated from a flower (West-Indian jasmine).

PubMed

Techo, Sujitra; Miyashita, Mika; Shibata, Chiyo; Tanaka, Naoto; Wisetkhan, Preeyarach; Visessanguan, Wonnop; Tanasupawat, Somboon

2016-12-01

A Gram-stain-positive, lactic acid bacterium, strain Ru20-1T, was isolated from a flower (West-Indian jasmine) collected from Kalasin province, Thailand. A polyphasic approach was used to determine the taxonomic position of this strain. Studies of morphological and biochemical characteristics revealed that strain Ru20-1T belonged to the genus Lactobacillus. The strain was heterofermentative, non-spore-forming and rod-shaped. It produced dl-lactic acid. Based on 16S rRNA gene sequence similarity, this strain was closely related to Lactobacillus lindneri LMG 14528T (96.8 %), Lactobacillus sanfranciscensis NRIC 1548T (95.4 %) and Lactobacillus florum NRIC 0771T (95.2 %), respectively. In addition, the pheS gene sequence of strain Ru20-1T was closely related to those of L. sanfranciscensis NRIC 1548T (92.0 %), L. lindneri LMG 14528T (89.0 %) and L. florum NRIC 0771T(85.0 %). Phylogenetic analysis indicated that strain Ru20-1T was clearly separated from closely related species of the genus Lactobacillus. The DNA G+C content of strain Ru20-1T was 47.8 mol %. The cell-wall peptidoglycan type was l-Lys-d-Asp. The major cellular fatty acids were C18 : 1ω9c, C20 : 0, C20 : 1ω9c and summed feature 7 (unknown 18.846 and/or C19 : 1ω6c and/or C19 : 0 cyclo). On the basis of the data provided, strain Ru20-1T represents a novel species of the genus Lactobacillus, for which the name Lactobacillus ixorae sp. nov. is proposed. The type strain is Ru20-1T (=LMG 29008T=NBRC 111239T=PCU 346T=TISTR 2381T).

Cryptic Nature of a Conserved, CD4-Inducible V3 Loop Neutralization Epitope in the Native Envelope Glycoprotein Oligomer of CCR5-Restricted, but Not CXCR4-Using, Primary Human Immunodeficiency Virus Type 1 Strains

PubMed Central

Lusso, Paolo; Earl, Patricia L.; Sironi, Francesca; Santoro, Fabio; Ripamonti, Chiara; Scarlatti, Gabriella; Longhi, Renato; Berger, Edward A.; Burastero, Samuele E.

2005-01-01

The external subunit of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env), gp120, contains conserved regions that mediate sequential interactions with two cellular receptor molecules, CD4 and a chemokine receptor, most commonly CCR5 or CXCR4. However, antibody accessibility to such regions is hindered by diverse protective mechanisms, including shielding by variable loops, conformational flexibility and extensive glycosylation. For the conserved neutralization epitopes hitherto described, antibody accessibility is reportedly unrelated to the viral coreceptor usage phenotype. Here, we characterize a novel, conserved gp120 neutralization epitope, recognized by a murine monoclonal antibody (MAb), D19, which is differentially accessible in the native HIV-1 Env according to its coreceptor specificity. The D19 epitope is contained within the third variable (V3) domain of gp120 and is distinct from those recognized by other V3-specific MAbs. To study the reactivity of MAb D19 with the native oligomeric Env, we generated a panel of PM1 cells persistently infected with diverse primary HIV-1 strains. The D19 epitope was conserved in the majority (23/29; 79.3%) of the subtype-B strains tested, as well as in selected strains from other genetic subtypes. Strikingly, in CCR5-restricted (R5) isolates, the D19 epitope was invariably cryptic, although it could be exposed by addition of soluble CD4 (sCD4); epitope masking was dependent on the native oligomeric structure of Env, since it was not observed with the corresponding monomeric gp120 molecules. By contrast, in CXCR4-using strains (X4 and R5X4), the epitope was constitutively accessible. In accordance with these results, R5 isolates were resistant to neutralization by MAb D19, becoming sensitive only upon addition of sCD4, whereas CXCR4-using isolates were neutralized regardless of the presence of sCD4. Other V3 epitopes examined did not display a similar divergence in accessibility based on coreceptor usage phenotype. These results provide the first evidence of a correlation between HIV-1 biological phenotype and neutralization sensitivity, raising the possibility that the in vivo evolution of HIV-1 coreceptor usage may be influenced by the selective pressure of specific host antibodies. PMID:15890935

Characterization of plant-growth promoting diazotrophic bacteria isolated from field grown Chinese cabbage under different fertilization conditions.

PubMed

Yim, Woo-Jong; Poonguzhali, Selvaraj; Madhaiyan, Munusamy; Palaniappan, Pitchai; Siddikee, M A; Sa, Tongmin

2009-04-01

Diazotrophic bacteria isolated from the rhizosphere of Chinese cabbage were assessed for other plant growth promoting characteristics viz., production of IAA, ethylene, ACC deaminase, phosphate solubilization, and gnotobiotic root elongation. Their effect on inoculation to Chinese cabbage was also observed under growth chamber conditions. A total of 19 strains that showed higher nitrogenase activity identified by 16S rRNA gene sequence analysis were found to be the members of the genera Pseudomonas and Agrobacterium belonging to alpha- and gamma-Proteobacteria groups. These strains were also efficient in producing IAA and ACC deaminase though they produced low levels of ethylene and no phosphate solubilization. In addition, inoculation of selected diazotrophic bacterial strains significantly increased seedling length, dry weight, and total nitrogen when compared to uninoculated control. The colonization of crop plants by diazotrophic bacteria can be affected by many biotic and abiotic factors, and further studies are oriented towards investigating the factors that could influence the establishment of a selected bacterial community.

Strain-Specific Virolysis Patterns of Human Noroviruses in Response to Alcohols

PubMed Central

Park, Geun Woo; Collins, Nikail; Barclay, Leslie; Hu, Liya; Prasad, B. V. Venkataram; Lopman, Benjamin A.; Vinjé, Jan

2016-01-01

Alcohol-based hand sanitizers are widely used to disinfect hands to prevent the spread of pathogens including noroviruses. Alcohols inactivate norovirus by destruction of the viral capsid, resulting in the leakage of viral RNA (virolysis). Since conflicting results have been reported on the susceptibility of human noroviruses against alcohols, we exposed a panel of 30 human norovirus strains (14 GI and 16 GII strains) to different concentrations (50%, 70%, 90%) of ethanol and isopropanol and tested the viral RNA titer by RT-qPCR. Viral RNA titers of 10 (71.4%), 14 (100%), 3 (21.4%) and 7 (50%) of the 14 GI strains were reduced by > 1 log10 RNA copies/ml after exposure to 70% and 90% ethanol, and 70% and 90% isopropanol, respectively. RNA titers of 6 of the 7 non-GII 4 strains remained unaffected after alcohol exposure. Compared to GII strains, GI strains were more susceptible to ethanol than to isopropanol. At 90%, both alcohols reduced RNA titers of 8 of the 9 GII.4 strains by ≥ 1 log10 RNA copies/ml. After exposure to 70% ethanol, RNA titers of GII.4 Den Haag and Sydney strains decreased by ≥ 1.9 log10, whereas RNA reductions for GII.4 New Orleans strains were < 0.5 log10. To explain these differences, we sequenced the complete capsid gene of the 9 GII.4 strains and identified 17 amino acid substitutions in the P2 region among the 3 GII.4 variant viruses. When comparing with an additional set of 200 GII.4 VP1 sequences, only S310 and P396 were present in all GII.4 New Orleans viruses but not in the ethanol-sensitive GII.4 Sydney and GII.4 Den Haag viruses Our data demonstrate that alcohol susceptibility patterns between different norovirus genotypes vary widely and that virolysis data for a single strain or genotype are not representative for all noroviruses. PMID:27337036

Strain-Specific Virolysis Patterns of Human Noroviruses in Response to Alcohols.

PubMed

Park, Geun Woo; Collins, Nikail; Barclay, Leslie; Hu, Liya; Prasad, B V Venkataram; Lopman, Benjamin A; Vinjé, Jan

2016-01-01

Alcohol-based hand sanitizers are widely used to disinfect hands to prevent the spread of pathogens including noroviruses. Alcohols inactivate norovirus by destruction of the viral capsid, resulting in the leakage of viral RNA (virolysis). Since conflicting results have been reported on the susceptibility of human noroviruses against alcohols, we exposed a panel of 30 human norovirus strains (14 GI and 16 GII strains) to different concentrations (50%, 70%, 90%) of ethanol and isopropanol and tested the viral RNA titer by RT-qPCR. Viral RNA titers of 10 (71.4%), 14 (100%), 3 (21.4%) and 7 (50%) of the 14 GI strains were reduced by > 1 log10 RNA copies/ml after exposure to 70% and 90% ethanol, and 70% and 90% isopropanol, respectively. RNA titers of 6 of the 7 non-GII 4 strains remained unaffected after alcohol exposure. Compared to GII strains, GI strains were more susceptible to ethanol than to isopropanol. At 90%, both alcohols reduced RNA titers of 8 of the 9 GII.4 strains by ≥ 1 log10 RNA copies/ml. After exposure to 70% ethanol, RNA titers of GII.4 Den Haag and Sydney strains decreased by ≥ 1.9 log10, whereas RNA reductions for GII.4 New Orleans strains were < 0.5 log10. To explain these differences, we sequenced the complete capsid gene of the 9 GII.4 strains and identified 17 amino acid substitutions in the P2 region among the 3 GII.4 variant viruses. When comparing with an additional set of 200 GII.4 VP1 sequences, only S310 and P396 were present in all GII.4 New Orleans viruses but not in the ethanol-sensitive GII.4 Sydney and GII.4 Den Haag viruses Our data demonstrate that alcohol susceptibility patterns between different norovirus genotypes vary widely and that virolysis data for a single strain or genotype are not representative for all noroviruses.

Saccharomyces cerevisiae and non-Saccharomyces yeasts in grape varieties of the São Francisco Valley

PubMed Central

de Ponzzes-Gomes, Camila M.P.B.S.; de Mélo, Dângelly L.F.M.; Santana, Caroline A.; Pereira, Giuliano E.; Mendonça, Michelle O.C.; Gomes, Fátima C.O.; Oliveira, Evelyn S.; Barbosa, Antonio M.; Trindade, Rita C.; Rosa, Carlos A.

2014-01-01

The aims of this work was to characterise indigenous Saccharomyces cerevisiae strains in the naturally fermented juice of grape varieties Cabernet Sauvignon, Grenache, Tempranillo, Sauvignon Blanc and Verdejo used in the São Francisco River Valley, northeastern Brazil. In this study, 155 S. cerevisiae and 60 non-Saccharomyces yeasts were isolated and identified using physiological tests and sequencing of the D1/D2 domains of the large subunit of the rRNA gene. Among the non-Saccharomyces species, Rhodotorula mucilaginosa was the most common species, followed by Pichia kudriavzevii, Candida parapsilosis, Meyerozyma guilliermondii, Wickerhamomyces anomalus, Kloeckera apis, P. manshurica, C. orthopsilosis and C. zemplinina. The population counts of these yeasts ranged among 1.0 to 19 × 105 cfu/mL. A total of 155 isolates of S. cerevisiae were compared by mitochondrial DNA restriction analysis, and five molecular mitochondrial DNA restriction profiles were detected. Indigenous strains of S. cerevisiae isolated from grapes of the São Francisco Valley can be further tested as potential starters for wine production. PMID:25242923

Saccharomyces cerevisiae and non-Saccharomyces yeasts in grape varieties of the São Francisco Valley.

PubMed

de Ponzzes-Gomes, Camila M P B S; de Mélo, Dângelly L F M; Santana, Caroline A; Pereira, Giuliano E; Mendonça, Michelle O C; Gomes, Fátima C O; Oliveira, Evelyn S; Barbosa, Antonio M; Trindade, Rita C; Rosa, Carlos A

2014-01-01

The aims of this work was to characterise indigenous Saccharomyces cerevisiae strains in the naturally fermented juice of grape varieties Cabernet Sauvignon, Grenache, Tempranillo, Sauvignon Blanc and Verdejo used in the São Francisco River Valley, northeastern Brazil. In this study, 155 S. cerevisiae and 60 non-Saccharomyces yeasts were isolated and identified using physiological tests and sequencing of the D1/D2 domains of the large subunit of the rRNA gene. Among the non-Saccharomyces species, Rhodotorula mucilaginosa was the most common species, followed by Pichia kudriavzevii, Candida parapsilosis, Meyerozyma guilliermondii, Wickerhamomyces anomalus, Kloeckera apis, P. manshurica, C. orthopsilosis and C. zemplinina. The population counts of these yeasts ranged among 1.0 to 19 × 10(5) cfu/mL. A total of 155 isolates of S. cerevisiae were compared by mitochondrial DNA restriction analysis, and five molecular mitochondrial DNA restriction profiles were detected. Indigenous strains of S. cerevisiae isolated from grapes of the São Francisco Valley can be further tested as potential starters for wine production.

Quality of commercially produced Shigella serogrouping and serotyping antisera.

PubMed Central

Evins, G M; Gheesling, L L; Tauxe, R V

1988-01-01

Shigella grouping antisera from five manufacturers and typing antisera from two were purchased and evaluated with homologous and heterologous Shigella strains in the slide agglutination test. Only 31 of 73 (42%) antisera were satisfactory. In many instances, the antisera gave negative, as opposed to weak, reactions when they should have given strong positive reactions. Four reagents cross-reacted with Shigella strains. Of the 19 polyvalent grouping antisera to subgroups Shigella dysenteriae serotypes 1 through 7, S. flexneri serotypes 1 through 6, S. boydii serotypes 1 through 7, and S. sonnei forms I, II, only one S. sonnei reagent and five S. flexneri reagents were satisfactory with greater than or equal to 90% of the homologous strains. The reagent of poorest quality was satisfactory with only 18% of the homologous strains. There were three polyvalent antisera to the higher types of S. dysenteriae and S. boydii, which were available from only one company, that adequately identified 80, 63, and 65% of the homologous strains. Typing antisera were available from only two companies, and 30 of 51 (59%) were satisfactory. Commercially available Shigella antisera are inadequate for the laboratory testing required for planning the development of and evaluating Shigella vaccines. PMID:3281972

Genovariation Study of Hantavirus in Main Endemic Areas of Hemorrhagic Fever with Renal Syndrome in Hebei Province, China.

PubMed

Li, Qi; Cai, Yanan; Wei, Yamei; Han, Xu; Han, Zhanying; Zhang, Yanbo; Qi, Shunxiang; Xu, Yonggang

2016-01-01

Hemorrhagic fever with renal syndrome (HFRS) is an important infectious disease in Hebei Province. At present, cases from the northeast regions of the province account for >80% of the total incidences. However, studies that examine the region-specific genetic variations of the Hantavirus (HV), the causative pathogen for HFRS, have been lacking. Rodents were collected in northeast Hebei Province from 2004 to 2013, and the HV strains used in this study were isolated in 1993. Lung tissues were isolated from the rodents and HV antigen was detected by indirect immunofluorescence. The M1 and M2 fragments of HV M region were amplified by reverse transcription polymerase chain reaction (RT-PCR), cloned into pMDl9-T vector, sequenced and compared with representative standard stains for homology and phylogenetic analysis. A total of 21 samples of HV antigen-positive were collected. Real-time PCR analysis revealed that the 19 rodent lungs and two HV strains were positive for the SEO virus. 11 samples were chosen to sequence, and they shared 95.8%-99.8% in nucleotide homology, and 83.6%-99.2% when compared to the standard strains of SEO virus. Phylogenetic analysis demonstrated that all strains were grouped into the same S3 subtype. SEO was the major epidemic genotype of HV in the main HFRS endemic areas in Hebei Province, and S3 was the major subtype. There was minor genetic variation in HV over short term periods, while long term variations were higher.

Prevotella timonensis sp. nov., isolated from a human breast abscess.

PubMed

Glazunova, Olga O; Launay, Thierry; Raoult, Didier; Roux, Véronique

2007-04-01

Gram-negative anaerobic rods were isolated from a human breast abscess. Based on genotypic and phenotypic characteristics, the novel strain belonged to the genus Prevotella. Phylogenetic analysis based on 16S rRNA gene sequence comparisons showed that it was closely related to Prevotella buccalis (94 % 16S rRNA gene sequence similarity), Prevotella salivae (90 %) and Prevotella oris (89.1 %). The major cellular fatty acid was C(14 : 0) (19.5 %). The new isolate represents a novel species in the genus Prevotella, for which the name Prevotella timonensis sp. nov. is proposed. The type strain is strain 4401737(T) (=CIP 108522(T)=CCUG 50105(T)).

In vitro effects of Salvia officinalis L. essential oil on Candida albicans

PubMed Central

Sookto, Tularat; Srithavaj, Theerathavaj; Thaweboon, Sroisiri; Thaweboon, Boonyanit; Shrestha, Binit

2013-01-01

Objective To determine the anticandidal activities of Salvia officinalis L. (S. officinalis) essential oil against Candida albicans (C. albicans) and the inhibitory effects on the adhesion of C. albicans to polymethyl methacrylate (PMMA) resin surface. Methods Disc diffusion method was first used to test the anticandidal activities of the S. officinalis L. essential oil against the reference strain (ATCC 90028) and 2 clinical strains of C. albicans. Then the minimal inhibitory concentration (MIC) and minimal lethal concentration (MLC) were determined by modified membrane method. The adhesion of C. albicans to PMMA resin surface was assessed after immersion with S. officinalis L. essential oil at various concentrations of 1×MIC, 0.5×MIC and 0.25×MIC at room temperature for 30 min. One-way ANOVA was used to compare the Candida cell adhesion with the pretreatment agents and Tukey's test was used for multiple comparisons. Results S. officinalis L. essential oil exhibited anticandidal activity against all strains of C. albicans with inhibition zone ranging from 40.5 mm to 19.5 mm. The MIC and MLC of the oil were determined as 2.780 g/L against all test strains. According to the effects on C. albicans adhesion to PMMA resin surface, it was found that immersion in the essential oil at concentrations of 1×MIC (2.780 g/L), 0.5×MIC (1.390 g/L) and 0.25×MIC (0.695 g/L) for 30 min significantly reduced the adhesion of all 3 test strains to PMMA resin surface in a dose dependent manner (P<0.05). Conclusions S. officinalis L. essential oil exhibited anticandidal activities against C. albicans and had inhibitory effects on the adhesion of the cells to PMMA resin surface. With further testing and development, S. officinalis essential oil may be used as an antifungal denture cleanser to prevent candidal adhesion and thus reduce the risk of candida-associated denture stomatitis. PMID:23646301

Delftia tsuruhatensis WGR-UOM-BT1, a novel rhizobacterium with PGPR properties from Rauwolfia serpentina (L.) Benth. ex Kurz also suppresses fungal phytopathogens by producing a new antibiotic-AMTM.

PubMed

Prasannakumar, S P; Gowtham, H G; Hariprasad, P; Shivaprasad, K; Niranjana, S R

2015-11-01

The bacterial strain designated as WGR-UOM-BT1 isolated from rhizosphere of Rauwolfia serpentina exhibited broad-spectrum antifungal activity and also improved early plant growth. Based on morphological, biochemical and 16S rRNA gene sequence analyses, the strain BT1 was identified as Delftia tsuruhatensis (KF727978). Under in vitro conditions, the strain BT1 suppressed the growth of wide range of fungal phytopathogens. Purified antimicrobial metabolite from the strain BT1 was identified as nitrogen-containing heterocyclic compound, 'amino(5-(4-methoxyphenyl)-2-methyl-2-(thiophen-2-yl)-2,3-dihydrofuran-3-yl)methanol' (AMTM), with molecular mass of 340•40 and molecular formula of C17 H19 NO3 S. The strain BT1 was positive for rhizosphere colonization (tomato), IAA production, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity and phosphate solubilization. Under laboratory and greenhouse conditions, the strain BT1 promoted plant growth and suppressed foliar and root fungal pathogens of tomato. Therefore, antimicrobial and disease protection properties of strain BT1 could serve as an effective biological control candidate against devastating fungal pathogens of vegetable plants. Besides, the production of IAA, P solubilization and ACC deaminase activity enhance its potential as a biofertilizer and may stabilize the plant performance under fluctuating environmental conditions. In this study, we reported that Delftia tsuruhatensis WGR-UOM-BT1 strain has the plant growth promotion activities such as rhizosphere colonization (tomato), IAA production, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity and phosphate solubilization. This bacterial strain was found producing an antimicrobial nitrogen-containing heterocyclic compound identified as 'amino(5-(4-methoxyphenyl)-2-methyl-2-(thiophen-2-yl)-2,3-dihydrofuran-3-yl)methanol' [C17 H19 NO3 S] (AMTM), which is new to the bacterial world. © 2015 The Society for Applied Microbiology.

A Mechanism of Unidirectional Transformation, Leading to Antibiotic Resistance, Occurs within Nasopharyngeal Pneumococcal Biofilm Consortia

PubMed Central

2018-01-01

ABSTRACT Streptococcus pneumoniae acquires genes for resistance to antibiotics such as streptomycin (Str) or trimethoprim (Tmp) by recombination via transformation of DNA released by other pneumococci and closely related species. Using naturally transformable pneumococci, including strain D39 serotype 2 (S2) and TIGR4 (S4), we studied whether pneumococcal nasopharyngeal transformation was symmetrical, asymmetrical, or unidirectional. Incubation of S2Tet and S4Str in a bioreactor simulating the human nasopharynx led to the generation of SpnTet/Str recombinants. Double-resistant pneumococci emerged soon after 4 h postinoculation at a recombination frequency (rF) of 2.5 × 10−4 while peaking after 8 h at a rF of 1.1 × 10−3. Acquisition of antibiotic resistance genes by transformation was confirmed by treatment with DNase I. A high-throughput serotyping method demonstrated that all double-resistant pneumococci belonged to one serotype lineage (S2Tet/Str) and therefore that unidirectional transformation had occurred. Neither heterolysis nor availability of DNA for transformation was a factor for unidirectional transformation given that the density of each strain and extracellular DNA (eDNA) released from both strains were similar. Unidirectional transformation occurred regardless of the antibiotic-resistant gene carried by donors or acquired by recipients and regardless of whether competence-stimulating peptide-receptor cross talk was allowed. Moreover, unidirectional transformation occurred when two donor strains (e.g., S4Str and S19FTmp) were incubated together, leading to S19FStr/Tmp but at a rF 3 orders of magnitude lower (4.9 × 10−6). We finally demonstrated that the mechanism leading to unidirectional transformation was due to inhibition of transformation of the donor by the recipient. PMID:29764945

Evaluation of streptococcal toxic shock-like syndrome caused by group B streptococcus in adults in Japan between 2009 and 2013.

PubMed

Ikebe, Tadayoshi; Chiba, Kazuki; Shima, Tomoko; Masuda, Chieko; Okuno, Rumi; Ohya, Hitomi; Ogata, Kikuyo; Katsukawa, Chihiro; Kawahara, Ryuji; Tominaga, Kiyoshi; Yabata, Junko; Tada, Yuki; Okabe, Nobuhiko; Watanabe, Haruo; Chang, Bin; Ogawa, Michinaga; Ohnishi, Makoto

2015-03-01

Infection with Streptococcus agalactiae has long been recognized in infants. In recent years, S. agalactiae is an important cause of morbidity and mortality among adults and among those with underlying medical condition. Several cases of GBS infection and more fulminant disease similar to streptococcal toxic shock syndrome have recently been reported. We report here that 19 S. agalactiae strains were isolated from streptococcal toxic shock-like syndrome cases involving adult patients in Japan between 2009 and 2013. The average age of the patients was 66.3 years. At least one underlying disease was present in 47.4% (9/19) of the patients. The most prevalent serotype among these strains was Ib. All serotype Ib strains belonged to clonal complex 10 and were ciprofloxacin resistant. In contrast, all strains were susceptible to penicillin G, ampicillin, cefazolin, cefotaxime, imipenem, panipenem, and linezolid. The characteristic type distributions of streptococcal toxic shock-like syndrome isolates differed between isolates obtained from vaginal swabs of women and infants with invasive infections. Copyright © 2014 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Tauopathy contributes to synaptic and cognitive deficits in a murine model for Alzheimer's disease.

PubMed

Stancu, Ilie-Cosmin; Ris, Laurence; Vasconcelos, Bruno; Marinangeli, Claudia; Goeminne, Léonie; Laporte, Vincent; Haylani, Laetitia E; Couturier, Julien; Schakman, Olivier; Gailly, Philippe; Pierrot, Nathalie; Kienlen-Campard, Pascal; Octave, Jean-Noël; Dewachter, Ilse

2014-06-01

Tau alterations are now considered an executor of neuronal demise and cognitive dysfunction in Alzheimer's disease (AD). Mouse models combining amyloidosis and tauopathy and their parental counterparts are important tools to further investigate the interplay of abnormal amyloid-β (Aβ) and Tau species in pathogenesis, synaptic and neuronal dysfunction, and cognitive decline. Here, we crossed APP/PS1 mice with 5 early-onset familial AD mutations (5xFAD) and TauP301S (PS19) transgenic mice, denoted F(+)/T(+) mice, and phenotypically compared them to their respective parental strains, denoted F(+)/T(-) and F(-)/T(+) respectively, as controls. We found dramatically aggravated tauopathy (~10-fold) in F(+)/T(+) mice compared to the parental F(-)/T(+) mice. In contrast, amyloidosis was unaltered compared to the parental F(+)/T(-) mice. Tauopathy was invariably and very robustly aggravated in hippocampal and cortical brain regions. Most important, F(+)/T(+) displayed aggravated cognitive deficits in a hippocampus-dependent spatial navigation task, compared to the parental F(+)/T(-) strain, while parental F(-)/T(+) mice did not display cognitive impairment. Basal synaptic transmission was impaired in F(+)/T(+) mice compared to nontransgenic mice and the parental strains (≥40%). Finally, F(+)/T(+) mice displayed a significant hippocampal atrophy (~20%) compared to nontransgenic mice, in contrast to the parental strains. Our data indicate for the first time that pathological Aβ species (or APP/PS1) induced changes in Tau contribute to cognitive deficits correlating with synaptic deficits and hippocampal atrophy in an AD model. Our data lend support to the amyloid cascade hypothesis with a role of pathological Aβ species as initiator and pathological Tau species as executor. © FASEB.

Comparative Genomics Study of Multi-Drug-Resistance Mechanisms in the Antibiotic-Resistant Streptococcus suis R61 Strain

PubMed Central

Zhang, Anding; Wu, Jiayan; Chen, Bo; Hua, Yafeng; Yu, Jun; Chen, Huanchun; Xiao, Jingfa; Jin, Meilin

2011-01-01

Background Streptococcus suis infections are a serious problem for both humans and pigs worldwide. The emergence and increasing prevalence of antibiotic-resistant S. suis strains pose significant clinical and societal challenges. Results In our study, we sequenced one multi-drug-resistant S. suis strain, R61, and one S. suis strain, A7, which is fully sensitive to all tested antibiotics. Comparative genomic analysis revealed that the R61 strain is phylogenetically distinct from other S. suis strains, and the genome of R61 exhibits extreme levels of evolutionary plasticity with high levels of gene gain and loss. Our results indicate that the multi-drug-resistant strain R61 has evolved three main categories of resistance. Conclusions Comparative genomic analysis of S. suis strains with diverse drug-resistant phenotypes provided evidence that horizontal gene transfer is an important evolutionary force in shaping the genome of multi-drug-resistant strain R61. In this study, we discovered novel and previously unexamined mutations that are strong candidates for conferring drug resistance. We believe that these mutations will provide crucial clues for designing new drugs against this pathogen. In addition, our work provides a clear demonstration that the use of drugs has driven the emergence of the multi-drug-resistant strain R61. PMID:21966396

Comparative genomics study of multi-drug-resistance mechanisms in the antibiotic-resistant Streptococcus suis R61 strain.

PubMed

Hu, Pan; Yang, Ming; Zhang, Anding; Wu, Jiayan; Chen, Bo; Hua, Yafeng; Yu, Jun; Chen, Huanchun; Xiao, Jingfa; Jin, Meilin

2011-01-01

Streptococcus suis infections are a serious problem for both humans and pigs worldwide. The emergence and increasing prevalence of antibiotic-resistant S. suis strains pose significant clinical and societal challenges. In our study, we sequenced one multi-drug-resistant S. suis strain, R61, and one S. suis strain, A7, which is fully sensitive to all tested antibiotics. Comparative genomic analysis revealed that the R61 strain is phylogenetically distinct from other S. suis strains, and the genome of R61 exhibits extreme levels of evolutionary plasticity with high levels of gene gain and loss. Our results indicate that the multi-drug-resistant strain R61 has evolved three main categories of resistance. Comparative genomic analysis of S. suis strains with diverse drug-resistant phenotypes provided evidence that horizontal gene transfer is an important evolutionary force in shaping the genome of multi-drug-resistant strain R61. In this study, we discovered novel and previously unexamined mutations that are strong candidates for conferring drug resistance. We believe that these mutations will provide crucial clues for designing new drugs against this pathogen. In addition, our work provides a clear demonstration that the use of drugs has driven the emergence of the multi-drug-resistant strain R61.

Genotypic and epitope characteristics of group A porcine rotavirus strains circulating in Canada.

PubMed

Naseer, Omer; Jarvis, Matthew C; Ciarlet, Max; Marthaler, Douglas G

2017-07-01

Surveillance of Rotavirus A (RVA) infections in North America swine populations are limited and not performed over a significant time period to properly assess the diversity of RVA strains in swine. The VP7 (G) and VP4 (P) genes of 32 Canadian RVA strains, circulating between 2009 and 2015 were sequenced, identifying the G3P[13], G5P[7], G9P[7], G9[13], and G9[19] genotype combinations. The Canadian RVA strains were compared to the RVA strains present in the swine ProSystems RCE rotavirus vaccine. The comparison revealed multiple amino acid differences in the G and P antigenic epitopes, regardless of the G and P genotypes but specifically in the Canadian G3, P[13] and P[19] genotypes. Our study further contributes to the characterization of RVA's evolution and disease mitigation among swine, which may optimize target vaccine design, thereby minimizing RVA disease in this economically important animal population. Copyright © 2017 Elsevier Inc. All rights reserved.

Comparative analysis of Staphylococcus epidermidis strains utilizing quantitative and cell surface shaving proteomics.

PubMed

Solis, Nestor; Cain, Joel A; Cordwell, Stuart J

2016-01-01

Staphylococcus epidermidis is an opportunistic pathogen that is an emerging risk factor in hospitals worldwide and is often difficult to eradicate as virulent strains produce a protective biofilm matrix. We utilized cell shaving proteomics to profile surface-exposed proteins from two fully genome sequenced S. epidermidis strains: the avirulent, non-biofilm forming ATCC12228 and the virulent, strongly adherent biofilm forming ATCC35984 (RP62A). A false positive control strategy was employed to calculate the probabilities of proteins being truly surface-exposed. A total of 78 surface-exposed proteins were identified, of which only 19 proteins were common to ATCC12228 and RP62A, and which thus represents the core surfaceome. S. epidermidis RP62A displayed additional proteins involved in biofilm formation (cell wall-associated Bhp and intercellular adhesion protein IcaB), surface antigenicity, peptidoglycan biosynthesis and antibiotic resistance. We concurrently profiled whole cell proteomes of the two strains using iTRAQ quantitation and LC-MS/MS. A total of 1610 proteins were confidently identified (representing 64% of the theoretical S. epidermidis proteome). One hundred and ninety one proteins were differentially abundant between strains. Proteins associated with RP62A were clustered into functions including Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-mediated defense, sulfate assimilation, antibiotic resistance and biofilm formation. Validation of the sulfate assimilation and cysteine/methionine biosynthesis pathways showed RP62A contained elevated levels (~25% increase) of methionine that are likely linked to biofilm formation. Cell shaving and quantitative proteomics identified proteins associated with a biofilm-forming, virulent strain of S. epidermidis (RP62A). These proteins show RP62A maintains an active CRISPR-mediated defense, as well as heightened antibiotic resistance in comparison to a non-virulent, non-biofilm forming strain. Increased abundances of sulfate assimilation proteins lead to elevated intracellular methionine. Proteins and their exposed peptides identified on the surface of S. epidermidis RP62A may be useful vaccine antigens in clinical settings if administered in at-risk patients prior to surgical implantations. Copyright © 2015 Elsevier B.V. All rights reserved.

Subclinical Cardiac Dysfunction Detected by Strain Imaging During Breast Irradiation With Persistent Changes 6 Weeks After Treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lo, Queenie; Liverpool Hospital, Sydney, NSW; Hee, Leia

Purpose: To evaluate 2-dimensional strain imaging (SI) for the detection of subclinical myocardial dysfunction during and after radiation therapy (RT). Methods and Materials: Forty women with left-sided breast cancer, undergoing only adjuvant RT to the left chest, were prospectively recruited. Standard echocardiography and SI were performed at baseline, during RT, and 6 weeks after RT. Strain (S) and strain rate (Sr) parameters were measured in the longitudinal, circumferential, and radial planes. Correlation of change in global longitudinal strain (GLS % and Δ change) and the volume of heart receiving 30 Gy (V30) and mean heart dose (MHD) were examined. Results: Leftmore » ventricular ejection fraction was unchanged; however, longitudinal systolic S and Sr and radial S were significantly reduced during RT and remained reduced at 6 weeks after treatment [longitudinal S (%) −20.44 ± 2.66 baseline vs −18.60 ± 2.70* during RT vs −18.34 ± 2.86* at 6 weeks after RT; longitudinal Sr (s{sup −1}) −1.19 ± 0.21 vs −1.06 ± 0.18* vs −1.06 ± 0.16*; radial S (%) 56.66 ± 18.57 vs 46.93 ± 14.56* vs 49.22 ± 15.81*; *P<.05 vs baseline]. Diastolic Sr were only reduced 6 weeks after RT [longitudinal E Sr (s{sup −1}) 1.47 ± 0.32 vs 1.29 ± 0.27*; longitudinal A Sr (s{sup −1}) 1.19 ± 0.31 vs 1.03 ± 0.24*; *P<.05 vs baseline], whereas circumferential strain was preserved throughout. A modest correlation between S and Sr and V30 and MHD was observed (GLS Δ change and V30 ρ = 0.314, P=.05; GLS % change and V30 ρ = 0.288, P=.076; GLS Δ change and MHD ρ = 0.348, P=.03; GLS % change and MHD ρ = 0.346, P=.031). Conclusions: Subclinical myocardial dysfunction was detected by 2-dimensional SI during RT, with changes persisting 6 weeks after treatment, though long-term effects remain unknown. Additionally, a modest correlation between strain reduction and radiation dose was observed.« less

The Antiphagocytic Activity of SeM of Streptococcus equi Requires Capsule.

PubMed

Timoney, John F; Suther, Pranav; Velineni, Sridhar; Artiushin, Sergey C

2014-01-01

Resistance to phagocytosis is a crucial virulence property of Streptococcus equi (Streptococcus equi subsp. equi; Se), the cause of equine strangles. The contribution and interdependence of capsule and SeM to killing in equine blood and neutrophils were investigated in naturally occurring strains of Se. Strains CF32, SF463 were capsule and SeM positive, strains Lex90, Lex93 were capsule negative and SeM positive and strains Se19, Se1-8 were capsule positive and SeM deficient. Phagocytosis and killing of Se19, Se1-8, Lex90 and Lex93 in equine blood and by neutrophils suspended in serum were significantly (P ≤ 0.02) greater compared to CF32 and SF463. The results indicate capsule and SeM are both required for resistance to phagocytosis and killing and that the anti-phagocytic property of SeM is greatly reduced in the absence of capsule.

High Phenotypic Variability among Representative Strains of Common Salmonella enterica Serovars with Possible Implications for Food Safety.

PubMed

Abdullah, Wan Zawiah Wan; Mackey, Bernard M; Karatzas, Kimon Andreas G

2018-01-01

Salmonella is an important foodborne pathogen, whose ability to resist stress and survive can vary among strains. This variability is normally not taken into account when predictions are made about survival in foods with negative consequences. Therefore, we examined the contribution of variable phenotypic properties to survival under stress in 10 Salmonella serovars. One strain (Typhimurium 10) was intentionally RpoS-negative; however, another strain (Heidelberg) showed an rpoS mutation, rendering it inactive. We assessed an array of characteristics (motility, biofilm formation, bile resistance, acid resistance, and colony morphology) that show major variability among strains associated with a 10- to 19-fold difference between the highest and the lowest strain for most characteristics. The RpoS status of isolates did not affect variability in the characteristics, with the exception of resistance to NaCl, acetic acid, lactic acid, and the combination of acetic acid and salt, where the variability between the highest and the lowest strain was reduced to 3.1-fold, 1.7-fold, 2-fold, and 1.7-fold, respectively, showing that variability was significant among RpoS-positive strains. Furthermore, we also found a good correlation between acid resistance and lysine decarboxylase activity, showing its importance for acid resistance, and demonstrated a possible role of RpoS in the lysine decarboxylase activity in Salmonella.

Improved immunogenicity of tetanus toxoid by Brucella abortus S19 LPS adjuvant.

PubMed

Mohammadi, Mohsen; Kianmehr, Zahra; Kaboudanian Ardestani, Sussan; Gharegozlou, Behnaz

2014-09-01

Adjuvants are used to increase the immunogenicity of new generation vaccines, especially those based on recombinant proteins. Despite immunostimulatory properties, the use of bacterial lipopolysaccharide (LPS) as an adjuvant has been hampered due to its toxicity and pyrogenicity. Brucella abortus LPS is less toxic and has no pyrogenic properties compared to LPS from other gram negative bacteria. To evaluate the adjuvant effect of B. abortus (vaccine strain, S19) LPS for tetanus toxoid antigen (TT) and to investigate the protective effect of different tetanus vaccine preparations. LPS was extracted and purified from B. abortus S19 and KDO, glycan, phosphate content, and protein contamination were measured. Adipic acid dihydrazide (ADH) was used as a linker for conjugation of TT to LPS. Different amounts of B. abortus LPS, TT, TT conjugated with LPS, and TT mixed with LPS or complete Freund's adjuvant (CFA) were injected into mice and antibody production against TT was measured. The protective effect of induced antibodies was determined by LD50. Immunization of mice with TT+LPS produced the highest anti-TT antibody titer in comparison to the group immunized with TT without any adjuvant or the groups immunized with TT-LPS or TT+CFA. Tetanus toxid-S19 LPS also produced a 100% protective effect against TT in immunized mice. These data indicate that B. abortus LPS enhances the immune responses to TT and suggest the possible use of B. abortus LPS as an adjuvant in vaccine preparations.

Distinguishing between respiratory syncytial virus subgroups by protein profile analysis.

PubMed Central

Walpita, P; Mufson, M A; Stanek, R J; Pfeifer, D; Connor, J D

1992-01-01

We subgrouped 75 strains of respiratory syncytial virus by a protein profile method (PPM) which relies on different mobilities of the phosphoprotein in one-dimensional polyacrylamide gel electrophoresis and does not require monoclonal antibodies. When compared with enzyme immunoassay, PPM correctly subgrouped 54 of 56 subgroup A and all 19 subgroup B strains. Images PMID:1572961

The Effect of Vaccination on the Evolution and Population Dynamics of Avian Paramyxovirus-1

PubMed Central

Hudson, Peter J.; Poss, Mary

2010-01-01

Newcastle Disease Virus (NDV) is a pathogenic strain of avian paramyxovirus (aPMV-1) that is among the most serious of disease threats to the poultry industry worldwide. Viral diversity is high in aPMV-1; eight genotypes are recognized based on phylogenetic reconstruction of gene sequences. Modified live vaccines have been developed to decrease the economic losses caused by this virus. Vaccines derived from avirulent genotype II strains were developed in the 1950s and are in use globally, whereas Australian strains belonging to genotype I were developed as vaccines in the 1970s and are used mainly in Asia. In this study, we evaluated the consequences of attenuated live virus vaccination on the evolution of aPMV-1 genotypes. There was phylogenetic incongruence among trees based on individual genes and complete coding region of 54 full length aPMV-1 genomes, suggesting that recombinant sequences were present in the data set. Subsequently, five recombinant genomes were identified, four of which contained sequences from either genotype I or II. The population history of vaccine-related genotype II strains was distinct from other aPMV-1 genotypes; genotype II emerged in the late 19th century and is evolving more slowly than other genotypes, which emerged in the 1960s. Despite vaccination efforts, genotype II viruses have experienced constant population growth to the present. In contrast, other contemporary genotypes showed population declines in the late 1990s. Additionally, genotype I and II viruses, which are circulating in the presence of homotypic vaccine pressure, have unique selection profiles compared to nonvaccine-related strains. Collectively, these data show that vaccination with live attenuated viruses has changed the evolution of aPMV-1 by maintaining a large effective population size of a vaccine-related genotype, allowing for coinfection and recombination of vaccine and wild type strains, and by applying unique selective pressures on viral glycoproteins. PMID:20421950

[Salmonella spp. strains resistant to drugs].

PubMed

Białucha, Agata; Kozuszko, Sylwia; Gospodarek, Eugenia

2010-01-01

The aim of the study was retrospective analysis of Salmonella spp. strains isolated from patients of State Infectious Diseases Observatory Hospital of T. Browicz in Bydgoszcz (SZAK) and University of dr. A. Jurasz in Bydgoszcz (SU CM UMK) in 2006-2009. The percentages of Salmonella spp. strains resistant to at least one drug were: 19,0% in 2006, 12,5% in 2007, 50,6% in 2008 and 43,8% in the first half of 2009 year. The highest number of Salmonella spp. strains resistant to drugs were isolated from stool (96,7%) and from patients of SZAK (83,3%). Among all isolated Salmonella spp. strains resistant to drugs the highest percentage were S. enterica serovar Enteritidis (56,7%). Among S. enterica bacilli predominated resitant phenotypes to ampicillin, amoxicillin, chloramphenicol and nalidixic acid. The increasing number of strains resistant to ciprofloxacin (0,0 - 26,7%) and high percentage of strains resistant to nalidixic acid (97,3%) were noted. Decreasing resistance to chloramphenicol was observed in our study (54,5 - 14,3%).

A genome-wide study of two-component signal transduction systems in eight newly sequenced mutans streptococci strains

PubMed Central

2012-01-01

Background Mutans streptococci are a group of gram-positive bacteria including the primary cariogenic dental pathogen Streptococcus mutans and closely related species. Two component systems (TCSs) composed of a signal sensing histidine kinase (HK) and a response regulator (RR) play key roles in pathogenicity, but have not been comparatively studied for these oral bacterial pathogens. Results HKs and RRs of 8 newly sequenced mutans streptococci strains, including S. sobrinus DSM20742, S. ratti DSM20564 and six S. mutans strains, were identified and compared to the TCSs of S. mutans UA159 and NN2025, two previously genome sequenced S. mutans strains. Ortholog analysis revealed 18 TCS clusters (HK-RR pairs), 2 orphan HKs and 2 orphan RRs, of which 8 TCS clusters were common to all 10 strains, 6 were absent in one or more strains, and the other 4 were exclusive to individual strains. Further classification of the predicted HKs and RRs revealed interesting aspects of their putative functions. While TCS complements were comparable within the six S. mutans strains, S. sobrinus DSM20742 lacked TCSs possibly involved in acid tolerance and fructan catabolism, and S. ratti DSM20564 possessed 3 unique TCSs but lacked the quorum-sensing related TCS (ComDE). Selected computational predictions were verified by PCR experiments. Conclusions Differences in the TCS repertoires of mutans streptococci strains, especially those of S. sobrinus and S. ratti in comparison to S. mutans, imply differences in their response mechanisms for survival in the dynamic oral environment. This genomic level study of TCSs should help in understanding the pathogenicity of these mutans streptococci strains. PMID:22475007

Engineering genome-reduced Bacillus subtilis for acetoin production from xylose.

PubMed

Yan, Panpan; Wu, Yuanqing; Yang, Li; Wang, Zhiwen; Chen, Tao

2018-02-01

To investigate the capacity of a genome-reduced Bacillus subtilis strain as chassis cell for acetoin production from xylose. To endow the genome-reduced Bacillus subtilis strain BSK814 with the ability to utilize xylose, we inserted a native xyl operon into its genome and deleted the araR gene. The resulting strain BSK814A2 produced 2.94 g acetoin/l from 10 g xylose/l, which was 39% higher than control strain BSK19A2. The deletion of the bdhA and acoA genes further improved xylose utilization efficiency and increased acetoin production to 3.71 g/l in BSK814A4. Finally, BSK814A4 produced up to 23.3 g acetoin/l from 50 g xylose/l, with a yield of 0.46 g/g xylose. Both the titer and yield were 39% higher than those of control strain BSK19A4. As a chassis cell, genome-reduced B. subtilis showed significantly improved capacity for the production of the overflow product acetoin from xylose compared with wild-type strain.

Type VI Secretion Systems of Erwinia amylovora Contribute to Bacterial Competition, Virulence, and Exopolysaccharide Production.

PubMed

Tian, Yanli; Zhao, Yuqiang; Shi, Linye; Cui, Zhongli; Hu, Baishi; Zhao, Youfu

2017-06-01

The type VI secretion system (T6SS) plays a major role in mediating interbacterial competition and might contribute to virulence in plant pathogenic bacteria. However, the role of T6SS in Erwinia amylovora remains unknown. In this study, 33 deletion mutants within three T6SS clusters were generated in E. amylovora strain NCPPB1665. Our results showed that all 33 mutants displayed reduced antibacterial activities against Escherichia coli as compared with that of the wild-type (WT) strain, indicating that Erwinia amylovora T6SS are functional. Of the 33 mutants, 19 exhibited reduced virulence on immature pear fruit as compared with that of the WT strain. Among them, 6, 1, and 12 genes belonged to T6SS-1, T6SS-2, and T6SS-3 clusters, respectively. Interestingly, these 19 mutants also produced less amylovoran or levan or both. These findings suggest that E. amylovora T6SS play a role in bacterial competition and virulence possibly by influencing exopolysaccharide production.

Myocardial Deformation Measured by 3-Dimensional Speckle Tracking in Children and Adolescents With Systemic Arterial Hypertension.

PubMed

Navarini, Susanne; Bellsham-Revell, Hannah; Chubb, Henry; Gu, Haotian; Sinha, Manish D; Simpson, John M

2017-12-01

Systemic arterial hypertension predisposes children to cardiovascular risk in childhood and adult life. Despite extensive study of left ventricular (LV) hypertrophy, detailed 3-dimensional strain analysis of cardiac function in hypertensive children has not been reported. The aim of this study was to evaluate LV mechanics (strain, twist, and torsion) in young patients with hypertension compared with a healthy control group and assess factors associated with functional measurements. Sixty-three patients (26 hypertension and 37 normotensive) were enrolled (mean age, 14.3 and 11.4 years; 54% men and 41% men, respectively). All children underwent clinical evaluation and echocardiographic examination, including 3-dimensional strain. There was no difference in LV volumes and ejection fraction between the groups. Myocardial deformation was significantly reduced in those with hypertension compared with controls. For hypertensive and normotensive groups, respectively, global longitudinal strain was -15.1±2.3 versus -18.5±1.9 ( P <0.0001), global circumferential strain -15.2±3 versus -19.9±3.1 (<0.0001), global radial strain +44.0±11.3 versus 63.4±10.5 ( P <0.0001), and global 3-dimensional strain -26.1±3.8 versus -31.5±3.8 ( P <0.0001). Basal clockwise rotation, apical counterclockwise rotation, twist, and torsion were not significantly different. After multivariate regression analyses blood pressure, body mass index and LV mass maintained a significant relationship with measures of LV strain. Similar ventricular volumes and ejection fraction were observed in hypertensive and normotensive children, but children with hypertension had significantly lower strain indices. Whether reduced strain might predict future cardiovascular risk merits further longitudinal study. © 2017 American Heart Association, Inc.

Lactobacillus silagincola sp. nov. and Lactobacillus pentosiphilus sp. nov., isolated from silage.

PubMed

Tohno, Masanori; Tanizawa, Yasuhiro; Irisawa, Tomohiro; Masuda, Takaharu; Sakamoto, Mitsuo; Arita, Masanori; Ohkuma, Moriya; Kobayashi, Hisami

2017-09-01

Three Gram-stain positive, non-motile, non-spore-forming, catalase-negative and rod-shaped bacterial strains (IWT5T, IWT25T and IWT140), isolated from silage, were investigated by using a polyphasic taxonomic approach. Strains IWT5T and IWT25T grew at 10-37 °C and 30-37 °C, and at pH 4.0-7.5 and 4.0-7.0, respectively. The G+C contents of genomic DNA of strains IWT5T and IWT25T were 43.2 and 44.4 mol%, respectively. Strains IWT5T and IWT25T contained C16 : 0, C18 : 1 ω9c and summed feature 7 (unknown 18.846/C19 : 1 ω6c/C19 : 0cyclo ω10c) as the major fatty acids. Strain IWT5T was most closely related to the type strains of Lactobacillus mixtipabuli (99.9 % 16S rRNA gene sequence similarity) and Lactobacillus silagei (99.5 %). For IWT25T, the 16S rRNA gene sequence similarities with the closely related neighbour type strains L. mixtipabuli and L. silagei were 99.5 and 99.5 %, respectively. The 16S rRNA gene sequence similarities among the three novel isolates were 99.5-99.9 %. The average nucleotide identities of strains IWT5T and IWT25T to other neighbours of the genus Lactobacillus were less than 82 % and the genomes of IWT25T and IWT140 shared 97.3 % average nucleotide identity, demonstrating that the three strains were allocated to two different novel species of the genus Lactobacillus. Together with multilocus sequence analysis, phenotypic and chemotaxonomic characteristics, strains IWT5T (=JCM 31144T=DSM 102973T) and IWT25T (=JCM 31145T=DSM 102974T) are proposed as the type strains of novel species of the genus Lactobacillus, with the names Lactobacillus silagincola sp. nov. and Lactobacillus pentosiphilus sp. nov., respectively.

Molecular and phenotypic characterization of strains of Shigella sonnei isolated over 31 years suggests the circulation of two prevalent subtypes in São Paulo State, Brazil.

PubMed

Seribelli, Amanda Ap; Frazão, Miliane R; Medeiros, Marta I Cazentini; Falcão, Juliana P

2016-07-01

Shigella sonnei is an important causative agent of bacillary dysentery worldwide that has recently emerged in developing countries. However, there are few studies that have characterized strains ofS. sonnei isolated in Brazil. The aims of this study were to assess the presence of 12 virulence genes, the antimicrobial resistance profile against 16 drugs and the genotypic diversity of strains of S. sonnei isolated in this country. Seventy-two strains of S. sonnei isolated from human diarrhoeic faeces in São Paulo State, Brazil from 1983-2014 were studied. All of the strains contained the ipaH, iuc and sigA genes. The ipaBCD gene was detected in 19 % of the strains, the ial and virF genes in 18 % and the sen gene in 10 % of the strains. The set1A, set1B, pic,sepA and sat genes were not detected. A total of 42 (58.3 %) strains were resistant to trimethoprim-sulfamethoxazole. Thirty (41.6 %) strains were resistant to tetracycline. The S. sonnei strains were grouped in two clusters called A and B by PFGE and ERIC-PCR, and the majority of the strains comprised in each cluster presented ≥80 % similarity. In conclusion, the pathogenic potential of the strains studied was highlighted by the presence of important virulence genes. The high rates of resistance to trimethoprim-sulfamethoxazole and tetracycline are alarming once those drugs can be used in the treatment of shigellosis. The PFGE and ERIC-PCR results suggest that there are two prevalent subtypes in the studied strains of S. sonnei that differed little over 31 years and have been contaminating humans and causing diseases in São Paulo State, Brazil.

The Relationship between the Structure of the Tick-Borne Encephalitis Virus Strains and Their Pathogenic Properties

PubMed Central

Belikov, Sergei I.; Kondratov, Ilya G.; Potapova, Ulyana V.; Leonova, Galina N.

2014-01-01

Tick-borne encephalitis virus (TBEV) is transmitted to vertebrates by taiga or forest ticks through bites, inducing disease of variable severity. The reasons underlying these differences in the severity of the disease are unknown. In order to identify genetic factors affecting the pathogenicity of virus strains, we have sequenced and compared the complete genomes of 34 Far-Eastern subtype (FE) TBEV strains isolated from patients with different disease severity (Primorye, the Russian Far East). We analyzed the complete genomes of 11 human pathogenic strains isolated from the brains of dead patients with the encephalitic form of the disease (Efd), 4 strains from the blood of patients with the febrile form of TBE (Ffd), and 19 strains from patients with the subclinical form of TBE (Sfd). On the phylogenetic tree, pathogenic Efd strains formed two clusters containing the prototype strains, Senzhang and Sofjin, respectively. Sfd strains formed a third separate cluster, including the Oshima strain. The strains that caused the febrile form of the disease did not form a separate cluster. In the viral proteins, we found 198 positions with at least one amino acid residue substitution, of which only 17 amino acid residue substitutions were correlated with the variable pathogenicity of these strains in humans and they authentically differed between the groups. We considered the role of each amino acid substitution and assumed that the deletion of 111 amino acids in the capsid protein in combination with the amino acid substitutions R16K and S45F in the NS3 protease may affect the budding process of viral particles. These changes may be the major reason for the diminished pathogenicity of TBEV strains. We recommend Sfd strains for testing as attenuation vaccine candidates. PMID:24740396

Bradyrhizobium valentinum sp. nov., isolated from effective nodules of Lupinus mariae-josephae, a lupine endemic of basic-lime soils in Eastern Spain.

PubMed

Durán, David; Rey, Luis; Navarro, Albert; Busquets, Antonio; Imperial, Juan; Ruiz-Argüeso, Tomás

2014-07-01

Bacterial strains isolated from nitrogen-fixing nodules of Lupinus mariae-josephae have been characterized following genetic, phenotypic and symbiotic approaches. Analysis of 16S rRNA genes placed them in a group together with Bradyrhizobium elkanii USDA 76(T), B. pachyrhizi PAC48(T), B. jicamae PAC68(T), 'B. retamae' Ro19(T) and B. lablabi CCBAU 23086(T) with over 99.0% identity. Phylogenetic analysis of concatenated housekeeping genes, recA, atpD and glnII, suggested that L. mariae-josephae strains represent a new Bradyrhizobium species, closely related to B. lablabi CCBAU 23086(T), B. jicamae PAC68(T) and 'B. retamae' Ro19(T) with 92.1, 91.9 and 90.8% identity, respectively. These results are consistent with overall genomic identities calculated as Average Nucleotide Identity (ANIm) using draft genomic sequences obtained for relevant strains. While L. mariae-josephae strains LmjM3(T)/LmjM6 exhibited a 99.2% ANIm value, they were significantly distant (<93% ANIm) from type strains of their closest species ('B. retamae' Ro19(T), B. lablabi CCBAU 23086(T) and B. jicamae PAC68(T)). Whole-cell matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (WC-MALDI-TOF-MS) analysis of proteomic patterns of the same strains was consistent with these results. The symbiosis-related genes nodC, nodA and nifH genes from strains nodulating L. mariae-josephae were phylogenetically related to those from 'B. retamae' Ro19(T), but divergent from those of strains that nodulate other lupine species. Based on genetic, genomic, proteomic and phenotypic data presented in this study, L. mariae-josephae nodulating strains LmjM3(T), LmjM6 and LmjM2 should be grouped within a new species for which the name Bradyrhizobium valentinum sp. nov. is proposed (type strain LmjM3(T)=CECT 8364(T), LMG 2761(T)). Copyright © 2014 Elsevier GmbH. All rights reserved.

Bromomethylthioindole Inspired Carbazole Hybrids as Promising Class of Anti-MRSA Agents

PubMed Central

2016-01-01

Series of N-substituted carbazole analogues bearing an indole ring were synthesized as anti-methicillin-resistant Staphylococcus aureus (MRSA) agents from a molecular hybridization approach. The representative compound 19 showed an MIC = 1 μg/mL against a panel of MRSA clinical isolates as it possessed comparable in vitro activities to that of vancomycin. Moreover, compound 19 also exhibited MIC = 1 μg/mL activities against a recent identified Z172 MRSA strain (vancomycin-intermediate and daptomycin-nonsusceptible phenotype) and the vancomycin-resistant Enterococcus faecalis (VRE) strain. In a mouse model with lethal infection of MRSA (4N216), a 75% survival rate was observed after a single dose of compound 19 was intravenously administered at 20 mg/kg. In light of their equipotent activities against different MRSA isolates and VRE strain, the data underscore the importance of designed hybrid series for the development of new N-substituted carbazoles as potential anti-MRSA agents. PMID:27994762

Serotype Distribution and Antimicrobial Resistance of Streptococcus pneumoniae Isolates from Pediatric Patients in Singapore

PubMed Central

Soh, Shirlena Wee-Ling; Poh, Chit Laa; Lin, Raymond V. Tzer Pin

2000-01-01

One hundred eighty Streptococcus pneumoniae strains isolated from children at a pediatric hospital in Singapore from 1997 to 1999 were serotyped and their antimicrobial susceptibility patterns were determined. Sixty-three percent of the isolates were resistant to penicillin. Significantly large numbers of the strains investigated were resistant to trimethoprim-sulfamethoxazole (87.8%), tetracycline (71.7%), erythromycin (67.8%), and chloramphenicol (40%). Penicillin and multidrug resistance was mostly associated with the frequently isolated S. pneumoniae isolates of serotypes (serotypes 19F, 23F, 6B, and 14). Isolates of serotype 19F, the serotype most commonly encountered in Singapore (41.1%), had the highest prevalence of penicillin (78.4%) and multidrug resistance (94.6%). Most of the invasive S. pneumoniae isolates (8 of 17; 47.1%) were of serotype 14. PMID:10898701

Micromonospora zeae sp. nov., a novel endophytic actinomycete isolated from corn root (Zea mays L.).

PubMed

Shen, Yue; Zhang, Yuejing; Liu, Chongxi; Wang, Xiangjing; Zhao, Junwei; Jia, Feiyu; Yang, Lingyu; Yang, Deguang; Xiang, Wensheng

2014-11-01

A novel actinomycete, designated strain NEAU-gq9(T), was isolated from corn root (Zea mays L.) and characterized using a polyphasic approach. The organism was found to have morphological and chemotaxonomic characteristics typical of the genus Micromonospora. On the basis of 16S rRNA gene sequence similarity studies, strain NEAU-gq9(T) was most closely related to Micromonospora zamorensis CR38(T) (99.3%), Micromonospora jinlongensis NEAU-GRX11(T) (99.2%), Micromonospora saelicesensis Lupac 09(T) (99.2%), Micromonospora chokoriensis 2-19(6)(T) (98.9%), Micromonospora coxensis 2-30-b(28)(T) (98.6%) and Micromonospora lupini Lupac 14N(T) (98.5%). Phylogenetic analysis based on the 16S rRNA gene and gyrB gene demonstrated that strain NEAU-gq9(T) is a member of the genus Micromonospora and supported the closest phylogenetic relationship to M. zamorensis CR38(T), M. jinlongensis NEAU-GRX11(T), M. saelicesensis Lupac 09(T), M. chokoriensis 2-19(6)(T) and M. lupini Lupac 14N(T). A combination of DNA-DNA hybridization, morphological and physiological characteristics indicated that the novel strain could be readily distinguished from the closest phylogenetic relatives. Therefore, it is proposed that strain NEAU-gq9(T) represents a novel species of the genus Micromonospora, for which the name Micromonospora zeae sp. nov. is proposed. The type strain is NEAU-gq9(T) (=CGMCC 4.7092(T)=DSM 45882(T)).

A Mechanism of Unidirectional Transformation, Leading to Antibiotic Resistance, Occurs within Nasopharyngeal Pneumococcal Biofilm Consortia.

PubMed

Lattar, Santiago M; Wu, Xueqing; Brophy, Jennifer; Sakai, Fuminori; Klugman, Keith P; Vidal, Jorge E

2018-05-15

Streptococcus pneumoniae acquires genes for resistance to antibiotics such as streptomycin (Str) or trimethoprim (Tmp) by recombination via transformation of DNA released by other pneumococci and closely related species. Using naturally transformable pneumococci, including strain D39 serotype 2 (S2) and TIGR4 (S4), we studied whether pneumococcal nasopharyngeal transformation was symmetrical, asymmetrical, or unidirectional. Incubation of S2 Tet and S4 Str in a bioreactor simulating the human nasopharynx led to the generation of Spn Tet/Str recombinants. Double-resistant pneumococci emerged soon after 4 h postinoculation at a recombination frequency (rF) of 2.5 × 10 -4 while peaking after 8 h at a rF of 1.1 × 10 -3 Acquisition of antibiotic resistance genes by transformation was confirmed by treatment with DNase I. A high-throughput serotyping method demonstrated that all double-resistant pneumococci belonged to one serotype lineage (S2 Tet/Str ) and therefore that unidirectional transformation had occurred. Neither heterolysis nor availability of DNA for transformation was a factor for unidirectional transformation given that the density of each strain and extracellular DNA (eDNA) released from both strains were similar. Unidirectional transformation occurred regardless of the antibiotic-resistant gene carried by donors or acquired by recipients and regardless of whether competence-stimulating peptide-receptor cross talk was allowed. Moreover, unidirectional transformation occurred when two donor strains (e.g., S4 Str and S19F Tmp ) were incubated together, leading to S19F Str/Tmp but at a rF 3 orders of magnitude lower (4.9 × 10 -6 ). We finally demonstrated that the mechanism leading to unidirectional transformation was due to inhibition of transformation of the donor by the recipient. IMPORTANCE Pneumococcal transformation in the human nasopharynx may lead to the acquisition of antibiotic resistance genes or genes encoding new capsular variants. Antibiotics and vaccines are currently putting pressure on a number of strains, leading to an increase in antibiotic resistance and serotype replacement. These pneumococcal strains are also acquiring virulence traits from vaccine types via transformation. In this study, we recapitulated multiple-strain colonization with strains carrying a resistance marker and selected for those acquiring resistance to two or three antibiotics, such as would occur in the human nasopharynx. Strains acquiring dual and triple resistance originated from one progenitor, demonstrating that transformation was unidirectional. Unidirectional transformation was the result of inhibition of transformation of donor strains. Unidirectional transformation has implications for the understanding of acquisition patterns of resistance determinants or capsule-switching events. Copyright © 2018 Lattar et al.

The role of the PI3K/mTOR signaling pathway in Staphylococcus epidermidis small colony variants intracellular survival.

PubMed

Magryś, Agnieszka; Bogut, Agnieszka; Kiełbus, Michał; Olender, Alina

2018-04-01

The objective of this study was to analyze how Staphylococcus epidermidis SCV and WT strains manipulate the PI3K/Akt/mTOR signaling pathway. Six S. epidermidis strains with normal phenotype (WT) and six S. epidermidis strains with SCV phenotype were isolated in parallel from six patients with the prosthetic hip joint infections. THP-1 activated cells were incubated with or without PI3K inhibitor-wortmannin or with mTOR inhibitor-rapamycin. Next, macrophages were exposed to S. epidermidis WT and SCV strains. After 4 h incubation, bacterial survival inside macrophages as well as PI3K-mTOR activation was analyzed. SCV strains of S. epidermidis increased the level of Akt phosphorylation, compared to uninfected macrophages and to their parental WT forms. Wild type variants of S. epidermidis phosphorylated Akt at similar or lower levels as control uninfected cells. Next, the induction of mTOR target, phosphorylated ribosomal protein S6, was measured in bacteria-infected macrophages. The level of phosphorylation was significantly reduced when the cells were exposed to WT strains of S. epidermidis. In contrast, the SCV strains activated S6 protein mostly at a level comparable to the control cells. Rapamycin inhibited mTOR activation as the number of p-S6 positive cells decreased in the tested cases. To conclude, the SCV strains activate the PI3K-Akt signaling pathway in opposite to WT strains. This fact however did not influence the increase in the number of live SCV bacteria as compared to the WT strains. Knowing that the PI3K-Akt pathway is involved in proinflammatory cytokines suppression, SCVs seem to use this pathway to reduce the inflammatory response during the infection.

Wild and aquaculture populations of the eastern oyster compared using microsatellites

USGS Publications Warehouse

Carlsson, J.; Morrison, C.L.; Reece, K.S.

2006-01-01

Five new microsatellite markers were developed for the eastern oyster (Crassostrea virginica), and allelic variability was compared between a wild Chesapeake Bay population (James River) and a hatchery strain (DEBY???). All loci amplified readily and demonstrated allelic variability with the number of alleles ranging from 16 to 36 in the wild population and from 11 to 19 in the DEBY??? strain. Average observed and expected heterozygosities were estimated at 0.66 and 0.80 in the hatchery sample. The corresponding estimates were 0.91 and 0.75 in the wild sample. Results indicated lower genetic variability in the DEBY??? strain and significant genetic differentiation between the wild population and hatchery strain. These microsatellite loci will prove valuable for future population genetic studies and in tracking of hatchery strains used in restoration. ?? The American Genetic Association. 2006. All rights reserved.

Halomonas sinaiensis sp. nov., a novel halophilic bacterium isolated from a salt lake inside Ras Muhammad Park, Egypt.

PubMed

Romano, Ida; Lama, Licia; Orlando, Pierangelo; Nicolaus, Barbara; Giordano, Assunta; Gambacorta, Agata

2007-11-01

An alkalitolerant and halotolerant bacterium, designated strain Sharm was isolated from a salt lake inside Ras Muhammad. The morphological, physiological and genetic characteristics were compared with those of related species of the genus Halomonas. The isolate grew optimally at pH 7.0, 5-15% NaCl at 35 degrees C. The cells were Gram-negative rods, facultative anaerobes. They accumulated glycine-betaine, as a major osmolyte, and ectoine and glutamate as minor components. The strain Sharm(T) biosynthetised alpha-glucosidase. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, and a novel phosphoglycolipid as major components. Ubiquinone with nine repetitive unities (Q9) was the only quinone found and, nC16:0 and C19:0 with cyclopropane were the main cellular fatty acids, accounting for 87.3% of total fatty acids. The G + C content of the genomic DNA was 64.7 mol %. The 16S rRNA sequence analysis indicated that strain Sharm was a member of the genus Halomonas. The closest relatives of the strain Sharm were Halomonas elongata and Halomonas eurihalina. However, DNA-DNA hybridisation results clearly indicated that strain Sham was a distinct species of Halomonas. On the basis of the evidence, we propose to assign strain Sharm as a new species of the genus Halomonas, H. sinaiensis sp. nov, with strain Sharm(T) as the type strain (DSM 18067(T); ATCC BAA-1308(T)).

In situ X-ray diffraction strain-controlled study of Ti–Nb–Zr and Ti–Nb–Ta shape memory alloys: crystal lattice and transformation features

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dubinskiy, S.; National University of Science and Technology “MISIS”, 4, Leninskiy prosp., Moscow 119049; Prokoshkin, S.

2014-02-15

Phase and structure transformations in biomedical Ti–21.8Nb–6.0Zr (TNZ) and Ti–19.7Nb–5.8Ta (TNT) shape memory alloys (at.%) under and without load in the − 150 to 100 °S temperature range are studied in situ using an original tensile module for a low-temperature chamber of an X-ray diffractometer. Alpha″- and beta-phase lattice parameters, the crystallographic resource of recovery strain, phase and structure transformation sequences, and microstress appearance and disappearance are examined, compared and discussed. For both alloys, the crystallographic resource of recovery strain decreases with temperature increase to become 4.5% for TNZ and 2.5% for TNT alloy (at RT). Loading at low temperaturesmore » leads to additional α″-phase formation and reorientation. Heating under load, as compared to strain-free heating, affects the reverse transformation sequence of both alloys in different ways. For TNZ alloy, strain-free heating results in simultaneous ω→β and α″→β transformations, whereas during heating under stress, they are sequential: β + ω→α″ precedes α″→β. For TNT alloy, strain-free heating results in reverse α″→β transformation, whereas during heating under stress, α″→β transformation is preceded by α″-phase reorientation. - Highlights: • Comparative in situ XRD analysis of Ti–Nb–Zr(Ta) shape memory alloys is realized. • Lattice parameters of β- and α″-phases are calculated in the − 150 to + 100 °C range. • The higher the temperature, the lower the α″→β transformation strain. • Loading at low temperatures results in α″-phase formation and reorientation. • Transformation sequences upon heating with and without loading are different.« less

Recent emergence of clonal group O25b:K1:H4-B2-ST131 ibeA strains among Escherichia coli poultry isolates, including CTX-M-9-producing strains, and comparison with clinical human isolates.

PubMed

Mora, Azucena; Herrera, Alexandra; Mamani, Rosalia; López, Cecilia; Alonso, María Pilar; Blanco, Jesús E; Blanco, Miguel; Dahbi, Ghizlane; García-Garrote, Fernando; Pita, Julia María; Coira, Amparo; Bernárdez, María Isabel; Blanco, Jorge

2010-11-01

To discern the possible spread of the Escherichia coli O25b:H4-ST131 clonal group in poultry and the zoonotic potential of avian strains, we made a retrospective search of our strain collection and compared the findings for those strains with the findings for current strains. Thus, we have characterized a collection of 19 avian O25b:H4-ST131 E. coli strains isolated from 1995 to 2010 which, interestingly, harbored the ibeA gene. Using this virulence gene as a criterion for selection, we compared those 19 avian strains with 33 human O25b:H4-ST131 ibeA-positive E. coli strains obtained from patients with extraintestinal infections (1993 to 2009). All 52 O25b:H4-ST131 ibeA-positive E. coli strains shared the fimH, kpsMII, malX, and usp genes but showed statistically significant differences in nine virulence factors, namely, papGIII, cdtB, sat, and kpsMII K5, which were associated with human strains, and iroN, kpsMII K1, cvaC, iss, and tsh, which were associated with strains of avian origin. The XbaI macrorestriction profiles of the 52 E. coli O25b:H4-ST131 ibeA-positive strains revealed 11 clusters (clusters I to XI) of >85% similarity, with four clusters including strains of human and avian origin. Cluster VII (90.9% similarity) grouped 10 strains (7 avian and 3 human strains) that mostly produced CTX-M-9 and that also shared the same virulence profile. Finally, we compared the macrorestriction profiles of the 12 CTX-M-9-producing O25b:H4-ST131 ibeA strains (7 avian and 5 human strains) identified among the 52 strains with those of 15 human O25b:H4-ST131 CTX-M-14-, CTX-M-15-, and CTX-M-32-producing strains that proved to be negative for ibeA and showed that they clearly differed in the level of similarity from the CTX-M-9-producing strains. In conclusion, E. coli clonal group O25b:H4-ST131 ibeA has recently emerged among avian isolates with the new acquisition of the K1 capsule antigen and includes CTX-M-9-producing strains. This clonal group represents a real zoonotic risk that has crossed the barrier between human and avian hosts.

Prevalence of Staphylococcus spp. nasal colonization among doctors of podiatric medicine and associated risk factors in Spain.

PubMed

de Benito, Sheila; Alou, Luis; Becerro-de-Bengoa-Vallejo, Ricardo; Losa-Iglesias, Marta Elena; Gómez-Lus, María Luisa; Collado, Luis; Sevillano, David

2018-01-01

This study aimed to estimate the prevalence of methicillin-susceptible and -resistant Staphylococcus aureus (MSSA and MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE) nasopharyngeal carriage among Doctors of Podiatric Medicine (Podiatrists) and to determine the potential risk factors. A cross-sectional study was carried out in 2016-2017 among 239 podiatrists in Spain. The presence of MSSA, MRSA, and MRSE was determined by microbiological analysis of nasal exudate and antimicrobial susceptibility was determined. Each podiatrist completed a questionnaire. The questionnaire comprised various parameters such as sex, age, podiatry experience duration, underlying diseases, prior antibiotic treatment, hospitalization during the last year, and use of a protective mask, an aspiration system, or gloves. The prevalence of MSSA, MRSA, and MRSE was 23.0%, 1.3%, and 23.8%, respectively. The MSSA prevalence was higher among podiatrists who did not use an aspiration system (32.3%) compared to those who did (19.3%; p  = 0.0305), and among podiatrists with respiratory diseases (36.8%) compared to those without (20.8%; p  = 0.0272). The MRSE prevalence was higher among men (33.7%) compared to women (8.6%; p  = 0.0089), podiatrists aged ≥50 (38.5%) compared to ≤35 (17.8%; p  = 0.0101), and podiatrists with ≥15 (39.3%) compared to ≤5 years of podiatry experience (12.5%; p  = 0.0015). Among the S. aureus strains, 84.5% were resistant to penicillin, 22.4% to erythromycin, 20.7% to clindamycin, and 12.7% to mupirocin. The MRSE strains were resistant to penicillin (93.0%), erythromycin (78.9%), and mupirocin (73.7%). The prevalence of S. aureus and S. epidermidis nasal carriage is low among Spanish podiatrists compared to other health professionals.

Combinatorial analysis of enzymatic bottlenecks of L-tyrosine pathway by p-coumaric acid production in Saccharomyces cerevisiae.

PubMed

Mao, Jiwei; Liu, Quanli; Song, Xiaofei; Wang, Hesuiyuan; Feng, Hui; Xu, Haijin; Qiao, Mingqiang

2017-07-01

To identify new enzymatic bottlenecks of L-tyrosine pathway for further improving the production of L-tyrosine and its derivatives. When ARO4 and ARO7 were deregulated by their feedback resistant derivatives in the host strains, the ARO2 and TYR1 genes, coding for chorismate synthase and prephenate dehydrogenase were further identified as new important rate-limiting steps. The yield of p-coumaric acid in the feedback-resistant strain overexpressing ARO2 or TYR1, was significantly increased from 6.4 to 16.2 and 15.3 mg l -1 , respectively. Subsequently, we improved the strain by combinatorial engineering of pathway genes increasing the yield of p-coumaric acid by 12.5-fold (from 1.7 to 21.3 mg l -1 ) compared with the wild-type strain. Batch cultivations revealed that p-coumaric acid production was correlated with cell growth, and the formation of by-product acetate of the best producer NK-M6 increased to 31.1 mM whereas only 19.1 mM acetate was accumulated by the wild-type strain. Combinatorial metabolic engineering provides a new strategy for further improvement of L-tyrosine or other metabolic biosynthesis pathways in S. cerevisiae.

Vaccine-induced rabies in a red fox (Vulpes vulpes): isolation of vaccine virus in brain tissue and salivary glands.

PubMed

Hostnik, Peter; Picard-Meyer, Evelyne; Rihtarič, Danijela; Toplak, Ivan; Cliquet, Florence

2014-04-01

Oral vaccination campaigns to eliminate fox rabies were initiated in Slovenia in 1995. In May 2012, a young fox (Vulpes vulpes) with typical rabies signs was captured. Its brain and salivary gland tissues were found to contain vaccine strain SAD B19. The Basic Logical Alignment Search Tool alignment of 589 nucleotides determined from the N gene of the virus isolated from the brain and salivary glands of the affected fox was 100% identical to the GenBank reference SAD B19 strain. Sequence analysis of the N and M genes (4,351 nucleotides) showed two nucleotide modifications at position 1335 (N gene) and 3114 (M gene) in the KC522613 isolate identified in the fox compared to SAD B19.

Rudaeicoccus suwonensis gen. nov., sp. nov., an actinobacterium isolated from the epidermal tissue of a root of a Phalaenopsis orchid.

PubMed

Kim, Soo-Jin; Jang, Yun-Hee; Ahn, Jae-Hyung; Weon, Hang-Yeon; Schumann, Peter; Chun, Se-Chul; Kwon, Soon-Wo; Kim, Wan-Gyu

2013-04-01

A bacterial strain, designated HOR6-4(T), was isolated from the epidermal tissue of a root of a Phalaenopsis orchid. Strain HOR6-4(T) was characterized using a polyphasic approach. The cells were aerobic, Gram-stain-positive, non-motile coccoids. Phylogenetic analysis of its 16S rRNA gene sequence revealed a clear affiliation with the family Dermacoccaceae. Strain HOR6-4(T) showed relatively low 16S rRNA gene sequence similarity (below 95.9 %) to type strains of species with validly published names, showing the highest sequence similarities to the type strains of Flexivirga alba (95.8 %) and Yimella lutea (95.5 %). The DNA G+C content of strain HOR6-4(T) was 64.7 mol%. Strain HOR6-4(T) had anteiso-C17 : 0 (19.3 %), 10-methyl C18 : 0 (tuberculostearic acid; 13.5 %) and 10-methyl C17 : 0 (11.7 %) as the major fatty acids and contained MK-8(H4) and MK-8(H6) as the predominant quinones. Polar lipids were diphosphatidylglycerol, phosphatidylinositol, three aminophospholipids, two phospholipids and an aminolipid. The peptidoglycan type was A4α, with an L-Lys-L-Thr-D-Glu interpeptide bridge with a glycine residue bound to the alpha-carboxyl group of D-Glu in position 2 of the peptide subunit. Mycolic acids were not present. On the basis of comparative analysis of phenotypic and phylogenetic traits, strain HOR6-4(T) is considered to represent a novel species in a new genus in the family Dermacoccaceae, for which the name Rudaeicoccus suwonensis gen. nov., sp. nov. is proposed. The type strain of Rudaeicoccus suwonensis is HOR6-4(T) ( = KACC 12637(T)  = DSM 19560(T)).

Safety Evaluation of Enterocin Producer Enterococcus sp. Strains Isolated from Traditional Turkish Cheeses.

PubMed

Avcı, Mine; Özden Tuncer, Banu

2017-07-06

The purpose of this study was to determine the antimicrobial activity and occurrence of bacteriocin structural genes in Enterococcus spp. isolated from different cheeses and also investigate some of their virulence factors. Enterococcus strains were isolated from 33 different cheeses. Enterococcus faecium (6 strains) and Enterococcus faecalis (5 strains) enterocin-producing strains were identified by 16S rDNA analyses. Structural genes entA, entB, entP and entX were detected in some isolates. Multiple enterocin structural genes were found in 7 strains. None of the tested enterococci demonstrated anyβ-haemolytic activity and only one strain had gelatinase activity. Six strains showed multiple antibiotic resistance patterns and in addition, vanA and several virulence genes were detected in many strains. Only E. faecalis MBE1-9 showed tyrosine decarboxylase activity and tdc gene was detected only in this strain.

[Molecular typing of 12 Brucella strains isolated in Guizhou province in 2010-2013].

PubMed

Wang, Yue; Chen, Hong; Liu, Ying; Zhou, Jingzhu; Li, Shijun; Hang, Yan; Tang, Guangpeng; Wang, Dingming; Chen, Guichun

2015-09-01

To identify and characterize the Brucella strains from Guizhou province in 2010-2013. A total of 12 strains of Brucella suspicious bacteria were isolated in Guizhou province from 2010 to 2013. Four strains (GZLL3, GZLL4, GZLL11 and SH2) were isolated from goat blood samples and eight strains (SH4, GZZY, GZSQ, GZZA, BR13001, BR13004, BR13005 and BR13006) were isolated from blood samples of patient 12 Brucella suspicious strains were identified and characterized using conventional methods. Brucella genus specific gene BCSP31-based PCR (BCSP31-PCR) was used to identify the genus of Brucella and IS711 insert sequence-based PCR (AMOS-PCR) was applied to identify the species of Brucella strains. Goats and patients originated Brucella strains were comparatively analysed using Pulse-field Gel Electrophoresis (PFGE). Both of conventional methods and PCR identified the 12 Brucella suspicious strains as B. melitensis biotype 3. BCSP31-PCR identification results showed that a specific DNA bands (223 bp) were detected in all the 12 strains and positive control samples with no DNA band in negative samples. AMOS-PCR amplified a 731 bp-DNA bands in all the 12 strains, with 731 bp, 498 bp and 275 bp in M5, S2 and A19 strains, respectively, and no DNA band was detected in the negative control samples. PFGE analysis showed that 12 Brucella isolates from patients and goats showed consistent PFGE patterns with the digestion of restriction enzyme Xba I. The epidemic species/type of Brucella in both human and animal in Guizhou province was B. melitensis biotype 3 and goat was the main animal source of infection of brucellosis in Guizhou province.

Genetic variation of the VP1 gene of the virulent duck hepatitis A virus type 1 (DHAV-1) isolates in Shandong province of China.

PubMed

Gao, Jiming; Chen, Junhao; Si, Xingkui; Xie, Zhijing; Zhu, Yanli; Zhang, Xingxiao; Wang, Shujing; Jiang, Shijin

2012-08-01

To investigate the relationship of the variation of virulence and the external capsid proteins of the pandemic duck hepatitis A virus type 1 (DHAV-1) isolates, the virulence, cross neutralization assays and the complete sequence of the virion protein 1 (VP1) gene of nine virulent DHAV-1 strains, which were isolated from infected ducklings with clinical symptoms in Shandong province of China in 2007-2008, were tested. The fifth generation duck embryo allantoic liquids of the 9 isolates were tested on 12-day-old duck embryos and on 7-day-old ducklings for the median embryonal lethal doses (ELD(50)s) and the median lethal doses (LD(50)s), respectively. The results showed that the ELD(50)s of embryonic duck eggs of the 9 DHAV-1 isolates were between 1.9 × 10(6)/mL to 1.44 × 10(7)/mL, while the LD(50)s were 2.39 × 10(5)/mL to 6.15 × 10(6)/mL. Cross-neutralization tests revealed that the 9 DHAV-1 isolates were completely neutralized by the standard serum and the hyperimmune sera against the 9 DHAV-1 isolates, respectively. Compared with other virulent, moderate virulent, attenuated vaccine and mild strains, the VP1 genes of the 9 strains shared 89.8%-99.7% similarity at the nucleotide level and 92.4%-99.6% at amino acid level with other DHAV-1 strains. There were three hypervariable regions at the C-terminus (aa 158-160, 180-193 and 205-219) and other variable points in VP1 protein, but which didn't cause virulence of DHAV-1 change.

Use of rpoB gene analysis for identification of nitrogen-fixing Paenibacillus species as an alternative to the 16S rRNA gene.

PubMed

da Mota, F F; Gomes, E A; Paiva, E; Rosado, A S; Seldin, L

2004-01-01

To avoid the limitations of 16S rRNA-based phylogenetic analysis for Paenibacillus species, the usefulness of the RNA polymerase beta-subunit encoding gene (rpoB) was investigated as an alternative to the 16S rRNA gene for taxonomic studies. Partial rpoB sequences were generated for the type strains of eight nitrogen-fixing Paenibacillus species. The presence of only one copy of rpoB in the genome of P. graminis strain RSA19(T) was demonstrated by denaturing gradient gel electrophoresis and hybridization assays. A comparative analysis of the sequences of the 16S rRNA and rpoB genes was performed and the eight species showed between 91.6-99.1% (16S rRNA) and 77.9-97.3% (rpoB) similarity, allowing a more accurate discrimination between the different species using the rpoB gene. Finally, 24 isolates from the rhizosphere of different cultivars of maize previously identified as Paenibacillus spp. were assigned correctly to one of the nitrogen-fixing species. The data obtained in this study indicate that rpoB is a powerful identification tool, which can be used for the correct discrimination of the nitrogen-fixing species of agricultural and industrial importance within the genus Paenibacillus.

Screening of Non- Saccharomyces cerevisiae Strains for Tolerance to Formic Acid in Bioethanol Fermentation.

PubMed

Oshoma, Cyprian E; Greetham, Darren; Louis, Edward J; Smart, Katherine A; Phister, Trevor G; Powell, Chris; Du, Chenyu

2015-01-01

Formic acid is one of the major inhibitory compounds present in hydrolysates derived from lignocellulosic materials, the presence of which can significantly hamper the efficiency of converting available sugars into bioethanol. This study investigated the potential for screening formic acid tolerance in non-Saccharomyces cerevisiae yeast strains, which could be used for the development of advanced generation bioethanol processes. Spot plate and phenotypic microarray methods were used to screen the formic acid tolerance of 7 non-Saccharomyces cerevisiae yeasts. S. kudriavzeii IFO1802 and S. arboricolus 2.3319 displayed a higher formic acid tolerance when compared to other strains in the study. Strain S. arboricolus 2.3319 was selected for further investigation due to its genetic variability among the Saccharomyces species as related to Saccharomyces cerevisiae and availability of two sibling strains: S. arboricolus 2.3317 and 2.3318 in the lab. The tolerance of S. arboricolus strains (2.3317, 2.3318 and 2.3319) to formic acid was further investigated by lab-scale fermentation analysis, and compared with S. cerevisiae NCYC2592. S. arboricolus 2.3319 demonstrated improved formic acid tolerance and a similar bioethanol synthesis capacity to S. cerevisiae NCYC2592, while S. arboricolus 2.3317 and 2.3318 exhibited an overall inferior performance. Metabolite analysis indicated that S. arboricolus strain 2.3319 accumulated comparatively high concentrations of glycerol and glycogen, which may have contributed to its ability to tolerate high levels of formic acid.

Screening of Non- Saccharomyces cerevisiae Strains for Tolerance to Formic Acid in Bioethanol Fermentation

PubMed Central

Oshoma, Cyprian E.; Greetham, Darren; Louis, Edward J.; Smart, Katherine A.; Phister, Trevor G.; Powell, Chris; Du, Chenyu

2015-01-01

Formic acid is one of the major inhibitory compounds present in hydrolysates derived from lignocellulosic materials, the presence of which can significantly hamper the efficiency of converting available sugars into bioethanol. This study investigated the potential for screening formic acid tolerance in non-Saccharomyces cerevisiae yeast strains, which could be used for the development of advanced generation bioethanol processes. Spot plate and phenotypic microarray methods were used to screen the formic acid tolerance of 7 non-Saccharomyces cerevisiae yeasts. S. kudriavzeii IFO1802 and S. arboricolus 2.3319 displayed a higher formic acid tolerance when compared to other strains in the study. Strain S. arboricolus 2.3319 was selected for further investigation due to its genetic variability among the Saccharomyces species as related to Saccharomyces cerevisiae and availability of two sibling strains: S. arboricolus 2.3317 and 2.3318 in the lab. The tolerance of S. arboricolus strains (2.3317, 2.3318 and 2.3319) to formic acid was further investigated by lab-scale fermentation analysis, and compared with S. cerevisiae NCYC2592. S. arboricolus 2.3319 demonstrated improved formic acid tolerance and a similar bioethanol synthesis capacity to S. cerevisiae NCYC2592, while S. arboricolus 2.3317 and 2.3318 exhibited an overall inferior performance. Metabolite analysis indicated that S. arboricolus strain 2.3319 accumulated comparatively high concentrations of glycerol and glycogen, which may have contributed to its ability to tolerate high levels of formic acid. PMID:26284784

Technical note: a pilot study using a mouse mastitis model to study differences between bovine associated coagulase-negative staphylococci.

PubMed

Breyne, K; De Vliegher, S; De Visscher, A; Piepers, S; Meyer, E

2015-02-01

Coagulase-negative staphylococci (CNS) are a group of bacteria classified as either minor mastitis pathogens or commensal microbiota. Recent research suggests species- and even strain-related epidemiological and genetic differences within the large CNS group. The current pilot study investigated in 2 experiments whether a mouse mastitis model validated for bovine Staphylococcus aureus can be used to explore further differences between CNS species and strains. In a first dose titration experiment, a low inoculum dose of S. aureus Newbould 305 (positive control) was compared with increasing inoculum doses of a Staphylococcus chromogenes strain originating from a chronic bovine intramammary infection to a sham-inoculated mammary glands (negative control). In contrast to the high bacterial growth following inoculation with S. aureus, S. chromogenes was retrieved in very low levels at 24 h postinduction (p.i.). In a second experiment, the inflammation inflicted by 3 CNS strains was studied in mice. The host immune response induced by the S. chromogenes intramammary strain was compared with the one induced by a Staphylococcus fleurettii strain originating from cow bedding sawdust and by a S. chromogenes strain originating from a teat apex of a heifer. As expected, at 28 and 48 h p.i., low bacterial growth and local neutrophil influx in the mammary gland were induced by all CNS strains. As hypothesized, bacterial growth p.i. was the lowest for S. fleurettii compared with that induced by the 2 S. chromogenes strains, and the overall immune response established by the 3 CNS strains was less pronounced compared with the one induced by S. aureus. Proinflammatory cytokine profiling revealed that S. aureus locally induced IL-6 and IL-1β but not TNF-α, whereas, overall, CNS-inoculated glands lacked a strong cytokine host response but also induced IL-1β locally. Compared with both other CNS strains, S. chromogenes from the teat apex inflicted a more variable IL-1β response characterized by a more intense local reaction in several mice. This pilot study suggests that an intraductal mouse model can mimic bovine CNS mastitis and has potential as a complementary in vivo tool for future CNS mastitis research. Furthermore, it indicates that epidemiologically different bovine CNS species or strains induce a differential host innate immune response in the murine mammary gland. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

The narrowing down of inoculated communities of coagulase-negative staphylococci in fermented meat models is modulated by temperature and pH.

PubMed

Stavropoulou, Despoina Angeliki; Van Reckem, Emiel; De Smet, Stefaan; De Vuyst, Luc; Leroy, Frédéric

2018-06-02

Coagulase-negative staphylococci (CNS) are involved in colour and flavour formation of fermented meats. Their communities are established either spontaneously, as in some artisan-type products, or using a starter culture. The latter usually consists of Staphylococcus carnosus and/or Staphylococcus xylosus strains, although strains from other CNS species also have potential for application. However, it is not entirely clear how the fitness of alternative starter cultures within a fermented meat matrix compares to conventional ones and how this may be affected by processing conditions. Therefore, the aim of this study was to assess the influence of two key processing conditions, namely temperature and acidity, on the competitiveness of a cocktail of five different strains of CNS belonging to species that are potentially important for meat fermentation (Staphylococcus xylosus 2S7-2, S. carnosus 833, Staphylococcus epidermidis ATCC 12228, Staphylococcus equorum DFL-S19, and Staphylococcus saprophyticus FPS1). To this end, fermented meat models consisting of cured meat batters with initial pH values of 5.3, 5.5, or 5.7 were inoculated with these strains, stuffed in containers, and incubated at 23, 30, or 37 °C. Both the pH level and the temperature influenced the composition of the CNS communities, giving a competitive advantage to the best adapted species. Staphylococcus xylosus preferred low temperature and mild acidity, whereas an elevated temperature selected for S. epidermidis and a low pH for S. carnosus. Under the conditions tested, S. saprophyticus and S. equorum were outcompeted by the three other CNS species. Hence, CNS communities in fermented meats are not only established based on the initial presence of specific species in the meat batter but also by their subsequent adaptation to the processing conditions during fermentation, potentially overruling the use of starter cultures. Copyright © 2018 Elsevier B.V. All rights reserved.

Novel Accurate Bacterial Discrimination by MALDI-Time-of-Flight MS Based on Ribosomal Proteins Coding in S10-spc-alpha Operon at Strain Level S10-GERMS

NASA Astrophysics Data System (ADS)

Tamura, Hiroto; Hotta, Yudai; Sato, Hiroaki

2013-08-01

Matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is one of the most widely used mass-based approaches for bacterial identification and classification because of the simple sample preparation and extremely rapid analysis within a few minutes. To establish the accurate MALDI-TOF MS bacterial discrimination method at strain level, the ribosomal subunit proteins coded in the S 10-spc-alpha operon, which encodes half of the ribosomal subunit protein and is highly conserved in eubacterial genomes, were selected as reliable biomarkers. This method, named the S10-GERMS method, revealed that the strains of genus Pseudomonas were successfully identified and discriminated at species and strain levels, respectively; therefore, the S10-GERMS method was further applied to discriminate the pathovar of P. syringae. The eight selected biomarkers (L24, L30, S10, S12, S14, S16, S17, and S19) suggested the rapid discrimination of P. syringae at the strain (pathovar) level. The S10-GERMS method appears to be a powerful tool for rapid and reliable bacterial discrimination and successful phylogenetic characterization. In this article, an overview of the utilization of results from the S10-GERMS method is presented, highlighting the characterization of the Lactobacillus casei group and discrimination of the bacteria of genera Bacillus and Sphingopyxis despite only two and one base difference in the 16S rRNA gene sequence, respectively.

Comparative genome analysis of Streptococcus infantarius subsp. infantarius CJ18, an African fermented camel milk isolate with adaptations to dairy environment.

PubMed

Jans, Christoph; Follador, Rainer; Hochstrasser, Mira; Lacroix, Christophe; Meile, Leo; Stevens, Marc J A

2013-03-22

Streptococcus infantarius subsp. infantarius (Sii) belongs to the Streptococcus bovis/Streptococcus equinus complex associated with several human and animal infections. Sii is a predominant bacterium in spontaneously fermented milk products in Africa. The genome sequence of Sii strain CJ18 was compared with that of other Streptococcus species to identify dairy adaptations including genome decay such as in Streptococcus thermophilus, traits for its competitiveness in spontaneous milk fermentation and to assess potential health risks for consumers. The genome of Sii CJ18 harbors several unique regions in comparison to Sii ATCC BAA-102T, among others an enlarged exo- and capsular polysaccharide operon; Streptococcus thermophilus-associated genes; a region containing metabolic and hypothetical genes mostly unique to CJ18 and the dairy isolate Streptococcus gallolyticus subsp. macedonicus; and a second oligopeptide transport operon. Dairy adaptations in CJ18 are reflected by a high percentage of pseudogenes (4.9%) representing genome decay which includes the inactivation of the lactose phosphotransferase system (lacIIABC) by multiple transposases integration. The presence of lacS and lacZ genes is the major dairy adaptation affecting lactose metabolism pathways also due to the disruption of lacIIABC.We constructed mutant strains of lacS, lacZ and lacIIABC and analyzed the resulting strains of CJ18 to confirm the redirection of lactose metabolism via LacS and LacZ.Natural competence genes are conserved in both Sii strains, but CJ18 contains a lower number of CRISPR spacers which indicates a reduced defense capability against alien DNA. No classical streptococcal virulence factors were detected in both Sii strains apart from those involved in adhesion which should be considered niche factors. Sii-specific virulence factors are not described. Several Sii-specific regions encoding uncharacterized proteins provide new leads for virulence analyses and investigation of the unclear association of dairy and clinical Sii with human diseases. The genome of the African dairy isolate Sii CJ18 clearly differs from the human isolate ATCC BAA-102T. CJ18 possesses a high natural competence predisposition likely explaining the enlarged genome. Metabolic adaptations to the dairy environment are evident and especially lactose uptake corresponds to S. thermophilus. Genome decay is not as advanced as in S. thermophilus (10-19%) possibly due to a shorter history in dairy fermentations.

Comparative genome analysis of Streptococcus infantarius subsp. infantarius CJ18, an African fermented camel milk isolate with adaptations to dairy environment

PubMed Central

2013-01-01

Background Streptococcus infantarius subsp. infantarius (Sii) belongs to the Streptococcus bovis/Streptococcus equinus complex associated with several human and animal infections. Sii is a predominant bacterium in spontaneously fermented milk products in Africa. The genome sequence of Sii strain CJ18 was compared with that of other Streptococcus species to identify dairy adaptations including genome decay such as in Streptococcus thermophilus, traits for its competitiveness in spontaneous milk fermentation and to assess potential health risks for consumers. Results The genome of Sii CJ18 harbors several unique regions in comparison to Sii ATCC BAA-102T, among others an enlarged exo- and capsular polysaccharide operon; Streptococcus thermophilus-associated genes; a region containing metabolic and hypothetical genes mostly unique to CJ18 and the dairy isolate Streptococcus gallolyticus subsp. macedonicus; and a second oligopeptide transport operon. Dairy adaptations in CJ18 are reflected by a high percentage of pseudogenes (4.9%) representing genome decay which includes the inactivation of the lactose phosphotransferase system (lacIIABC) by multiple transposases integration. The presence of lacS and lacZ genes is the major dairy adaptation affecting lactose metabolism pathways also due to the disruption of lacIIABC. We constructed mutant strains of lacS, lacZ and lacIIABC and analyzed the resulting strains of CJ18 to confirm the redirection of lactose metabolism via LacS and LacZ. Natural competence genes are conserved in both Sii strains, but CJ18 contains a lower number of CRISPR spacers which indicates a reduced defense capability against alien DNA. No classical streptococcal virulence factors were detected in both Sii strains apart from those involved in adhesion which should be considered niche factors. Sii-specific virulence factors are not described. Several Sii-specific regions encoding uncharacterized proteins provide new leads for virulence analyses and investigation of the unclear association of dairy and clinical Sii with human diseases. Conclusions The genome of the African dairy isolate Sii CJ18 clearly differs from the human isolate ATCC BAA-102T. CJ18 possesses a high natural competence predisposition likely explaining the enlarged genome. Metabolic adaptations to the dairy environment are evident and especially lactose uptake corresponds to S. thermophilus. Genome decay is not as advanced as in S. thermophilus (10-19%) possibly due to a shorter history in dairy fermentations. PMID:23521820

Digital data for quick response (QR) codes of alkalophilic Bacillus pumilus to identify and to compare bacilli isolated from Lonar Crator Lake, India.

PubMed

Rekadwad, Bhagwan N; Khobragade, Chandrahasya N

2016-06-01

Microbiologists are routinely engaged isolation, identification and comparison of isolated bacteria for their novelty. 16S rRNA sequences of Bacillus pumilus were retrieved from NCBI repository and generated QR codes for sequences (FASTA format and full Gene Bank information). 16SrRNA were used to generate quick response (QR) codes of Bacillus pumilus isolated from Lonar Crator Lake (19° 58' N; 76° 31' E), India. Bacillus pumilus 16S rRNA gene sequences were used to generate CGR, FCGR and PCA. These can be used for visual comparison and evaluation respectively. The hyperlinked QR codes, CGR, FCGR and PCA of all the isolates are made available to the users on a portal https://sites.google.com/site/bhagwanrekadwad/. This generated digital data helps to evaluate and compare any Bacillus pumilus strain, minimizes laboratory efforts and avoid misinterpretation of the species.

Enhancing the Thermostability and Immunogenicity of a Respiratory Syncytial Virus (RSV) Live-Attenuated Vaccine by Incorporating Unique RSV Line19F Protein Residues.

PubMed

Rostad, Christina A; Stobart, Christopher C; Todd, Sean O; Molina, Samuel A; Lee, Sujin; Blanco, Jorge C G; Moore, Martin L

2018-03-15

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infections in infants, and an effective vaccine is not yet available. We previously generated an RSV live-attenuated vaccine (LAV) candidate, DB1, which was attenuated by a low-fusion subgroup B F protein (BAF) and codon-deoptimized nonstructural protein genes. DB1 was immunogenic and protective in cotton rats but lacked thermostability and stability of the prefusion conformation of F compared to strains with the line19F gene. We hypothesized that substitution of unique residues from the thermostable A2-line19F strain could thermostabilize DB1 and boost its immunogenicity. We therefore substituted 4 unique line19F residues into the BAF protein of DB1 by site-directed mutagenesis and rescued the recombinant virus, DB1-QUAD. Compared to DB1, DB1-QUAD had improved thermostability at 4°C and higher levels of prefusion F as measured by enzyme-linked immunosorbent assays (ELISAs). DB1-QUAD was attenuated in normal human bronchial epithelial cells, in BALB/c mice, and in cotton rats but grew to wild-type titers in Vero cells. In mice, DB1-QUAD was highly immunogenic and generated significantly higher neutralizing antibody titers to a panel of RSV A and B strains than did DB1. DB1-QUAD was also efficacious against wild-type RSV challenge in mice and cotton rats. Thus, substitution of unique line19F residues into RSV LAV DB1 enhanced vaccine thermostability, incorporation of prefusion F, and immunogenicity and generated a promising vaccine candidate that merits further investigation. IMPORTANCE We boosted the thermostability and immunogenicity of an RSV live-attenuated vaccine candidate by substituting 4 unique residues from the RSV line19F protein into the F protein of the heterologous vaccine strain DB1. The resultant vaccine candidate, DB1-QUAD, was thermostable, attenuated in vivo , highly immunogenic, and protective against RSV challenge in mice and cotton rats. Copyright © 2018 American Society for Microbiology.

Youth Versus Adult “Weightlifting” Injuries Presenting to United States Emergency Rooms: Accidental Versus Nonaccidental Injury Mechanisms

PubMed Central

Myer, Gregory D.; Quatman, Carmen E.; Khoury, Jane; Wall, Eric J.; Hewett, Timothy E.

2014-01-01

Myer, GD, Quatman, CE, Khoury, J, Wall, EJ, and Hewett, TE. Youth versus adult “weightlifting” injuries presenting to united states emergency rooms: accidental versus nonaccidental injury mechanisms. J Strength Cond Res 23(7): 2054–2060, 2009—Resistance training has previously been purported to be unsafe and ineffective in children. The purpose of this investigation was to evaluate resistance training-related injuries presenting to U.S. emergency rooms by age, type, and mechanism of injury. We hypothesized that older athletes would sustain greater percentages of joint sprains and muscle strains, whereas younger athletes would sustain a greater percentage of accidental injuries that would result in an increased percentage of fractures in youths. The U.S. Consumer Product Safety Commission (CPSC) National Electronic Injury Surveillance System was queried from 2002 to 2005 using the CPSC code for “Weightlifting.” Subjects between the ages of 8 and 30 were grouped by age categories 8 to 13 (elementary/middle school age), 14 to 18 (high school), 19 to 22 (college), and 23 to 30 (adult). Injuries were classified as “accidental” if caused by dropped weight or improper equipment use. Multiple logistic regression was used to compare accidental injuries between age groups. The sample consisted of 4, 111 patients. Accidental injuries decreased (p < 0.05) with age: 8 to 13 > 14 to 18 > 19 to 22 years = 23 to 30 years. Conversely, sprain/strain injuries increased in each successive age group (p < 0.05). Evaluation of only the nonaccidental injuries (n = 2, 565) showed that the oldest categories (19–22 and 23–30 yr) demonstrated a greater percentage of sprains and strains relative to younger age categories (p < 0.001). Two thirds of the injuries sustained in the 8 to 13 group were to the hand and foot and were most often related to “dropping” and “pinching” in the injury descriptions, and there was an increased percentage of fractures in the 8 to 13 group relative to all other groups (p < 0.001). The study findings indicate that children have lower risk of resistance training-related joint sprains and muscle strains than adults. The majority of youth resistance training injuries are the result of accidents that are potentially preventable with increased supervision and stricter safety guidelines. PMID:19855330

Non-encapsulated strains reveal novel insights in invasion and survival of Streptococcus suis in epithelial cells.

PubMed

Benga, L; Goethe, R; Rohde, M; Valentin-Weigand, P

2004-09-01

Streptococcus suis is a porcine and human pathogen causing invasive diseases, such as meningitis or septicaemia. Host cell interactions of S. suis have been studied mainly with serotype 2 strains, but multiple capsular serotypes as well as non-typeable strains exist with diverse virulence features. At present, S. suis is considered an extracellular pathogen. However, whether or not it can also invade host cells is a matter of controversial discussions. We have assessed adherence and invasion of S. suis for HEp-2 epithelial cells by comparing 10 serotype 2 strains and four non-typeable (NT) strains. Only the NT strains and a non-encapsulated serotype 2 mutant strain, but none of the serotype 2 strains, adhered strongly and were invasive. Invasion seemed to be affected by environmental signals, as suggested from comparison of strains grown in different media. Further phenotypic and genotypic characterization revealed a high diversity among the different strains. Electron microscopic analysis of invasion of selected invasive NT strains indicated different uptake mechanisms. One strain induced large invaginations comparable to those seen in 'caveolae' mediated uptake, whereas invasion of the other strains was accompanied by formation of filipodia-like membrane protrusions. Invasion of all strains, however, was similarly susceptible to hypertonic sucrose, which inhibits receptor-mediated endocytosis. Irrespective of the uptake pathway, streptococci resided in acidified phago-lysosome like vacuoles. All strains, except one, survived intracellularly as well as extracellular acidic conditions. Survival seemed to be associated with the AdiS protein, an environmentally regulated arginine deiminase of S. suis. Concluding, invasion and survival of NT strains of S. suis in epithelial cells revealed novel evidence that S. suis exhibits a broad variety of virulence-associated features depending on genetic variation and regulation.

Identification of pink-pigmented bacteria isolated from environmental water samples and their biofilm formation abilities.

PubMed

Furuhata, Katsunori; Kato, Yuko; Goto, Keiichi; Saitou, Keiko; Sugiyama, Jun-Ichi; Hara, Motonobu; Fukuyama, Masahumi

2008-06-01

Sixty-seven strains of pink-pigmented bacteria, which were isolated from environmental water samples collected nationwide, were identified by partial 16S rDNA sequence analysis. In addition, the biofilm formation ability of the isolates was experimentally investigated. We could identify only 2 strains at the species level: Pedobacter roseus HS-38 and Runella slithyformis HS-77. The results showed that of the strains tested, 22 strains (32.8%) were Pedobacter spp., which was most frequently identified, followed by 19 strains (28.4%) of Arcicella spp., 16 strains (23.9%) of Deinococcus spp., 5 strains (7.5%) of Roseomonas spp., 4 strains (6.0%) of Flectobacillus spp. and 1 strain (1.5%) of Runella sp. Most isolates showed low similarity values to previously known species, and they were found to be novel species. At a result, it was difficult to identify environmental water-derived pink-pigmented bacteria at the species level. On the other hand, when we measured the absorbance by the crystal violet staining to examine the quantities of biofilm formation of these strains, fifty-five (82.0%) of the 67 isolates formed biofilm. The absorbance of Deinococcus sp. HS-75 was the highest (3.56). When comparing the absorbance values among the genera, Roseomonas spp. showed the highest absorbance (mean:1.62), followed by Deinococcus spp. (mean: 1.03), and Arcicella spp. (mean: 1.01). Strains of Flectobacillus spp. (mean: 0.48) and Pedobacter spp. (mean: 0.42) showed lower absorbance values. As above, it was shown that, at the species level, the pink-pigmented bacteria in the water in the Japanese environment had various levels of ability to form biofilm.

Field study of vaccination of cattle with Brucella abortus strains RB51 and 19 under high and low disease prevalence.

PubMed

Lord, V R; Schurig, G G; Cherwonogrodzky, J W; Marcano, M J; Melendez, G E

1998-08-01

To assess humoral and protective immunity in cattle vaccinated by 12 months with Brucella abortus vaccine strains RB51 and 19 under field conditions of high and low brucellosis prevalence. 450 seronegative female cattle: 330 three to eight months old (calves), and 120 ten to twelve months old (heifers). Ranch A had high prevalence (39%) of brucellosis, and ranch B had low prevalence (2%), as determined by results of conventional serologic testing: agar gel immunodiffusion and the ring test. Seronegative cattle were vaccinated once or twice with 5 x 10(9) colony-forming units of B abortus strain RB51 or once with strain 19. After vaccinating 285 cattle with strain RB51 and 165 with strain 19, 74 (26%) and 30 (18%), respectively, were bred to seropositive bulls, then were kept within the infected herd of origin. All cattle vaccinated with strain 19 seroconverted 30 days later. All 285 cattle vaccinated with strain RB51 had negative results for all serologic tests, including agar gel immunodiffusion. All RB51-vaccinated cattle that became pregnant had negative results for the ring test and for conventional serologic tests after their first calving. Strain RB51 can be used as a live organism vaccine without inducing antibody titers that interfere with serodiagnosis, and induced 100% protection against field strain B abortus-induced abortion in cattle vaccinated at least 1 year before mating to an infected bull. Vaccination with strain 19 under similar conditions was less effective than vaccination with strain RB51.

Comparative genomics of multidrug resistance in Acinetobacter baumannii.

PubMed

Fournier, Pierre-Edouard; Vallenet, David; Barbe, Valérie; Audic, Stéphane; Ogata, Hiroyuki; Poirel, Laurent; Richet, Hervé; Robert, Catherine; Mangenot, Sophie; Abergel, Chantal; Nordmann, Patrice; Weissenbach, Jean; Raoult, Didier; Claverie, Jean-Michel

2006-01-01

Acinetobacter baumannii is a species of nonfermentative gram-negative bacteria commonly found in water and soil. This organism was susceptible to most antibiotics in the 1970s. It has now become a major cause of hospital-acquired infections worldwide due to its remarkable propensity to rapidly acquire resistance determinants to a wide range of antibacterial agents. Here we use a comparative genomic approach to identify the complete repertoire of resistance genes exhibited by the multidrug-resistant A. baumannii strain AYE, which is epidemic in France, as well as to investigate the mechanisms of their acquisition by comparison with the fully susceptible A. baumannii strain SDF, which is associated with human body lice. The assembly of the whole shotgun genome sequences of the strains AYE and SDF gave an estimated size of 3.9 and 3.2 Mb, respectively. A. baumannii strain AYE exhibits an 86-kb genomic region termed a resistance island--the largest identified to date--in which 45 resistance genes are clustered. At the homologous location, the SDF strain exhibits a 20 kb-genomic island flanked by transposases but devoid of resistance markers. Such a switching genomic structure might be a hotspot that could explain the rapid acquisition of resistance markers under antimicrobial pressure. Sequence similarity and phylogenetic analyses confirm that most of the resistance genes found in the A. baumannii strain AYE have been recently acquired from bacteria of the genera Pseudomonas, Salmonella, or Escherichia. This study also resulted in the discovery of 19 new putative resistance genes. Whole-genome sequencing appears to be a fast and efficient approach to the exhaustive identification of resistance genes in epidemic infectious agents of clinical significance.

[Multiplication of Brucella abortus and production of nitric oxide in two macrophage cell lines of different origin].

PubMed

Serafino, J; Conde, S; Zabal, O; Samartino, L

2007-01-01

Brucella abortus is a bacterium which causes abortions and infertility in cattle and undulant fever in humans. It multiplies intracellularly, evading the mechanisms of cellular death. Nitric oxide (NO) is important in the regulation of the immune response. In the present work, we studied the ability of three B. abortus strains to survive intracellularly in two macrophage cell lines. The bacterial multiplication in both cell lines was determined at two different times in UFC/ ml units. Moreover the inoculated cells were also observed under light-field and fluorescence microscopy stained with Giemsa and acridine orange, respectively. The stain of both cellular lines showed similar results with respect to the UFC/ml determination. The presence of B. abortus was confirmed by electronic microscopy. In both macrophage cell lines inoculated with the rough strain RB51, the multiplication diminished and the level of NO was higher, compared with cells inoculated with smooth strains (S19 and 2308). These results suggest that the absence of O-chain of LPS probably affects the intracellular growth of B. abortus.

Virulence of invasive Salmonella Typhimurium ST313 in animal models of infection.

PubMed

Ramachandran, Girish; Panda, Aruna; Higginson, Ellen E; Ateh, Eugene; Lipsky, Michael M; Sen, Sunil; Matson, Courtney A; Permala-Booth, Jasnehta; DeTolla, Louis J; Tennant, Sharon M

2017-08-01

Salmonella Typhimurium sequence type (ST) 313 produces septicemia in infants in sub-Saharan Africa. Although there are known genetic and phenotypic differences between ST313 strains and gastroenteritis-associated ST19 strains, conflicting data about the in vivo virulence of ST313 strains have been reported. To resolve these differences, we tested clinical Salmonella Typhimurium ST313 and ST19 strains in murine and rhesus macaque infection models. The 50% lethal dose (LD50) was determined for three Salmonella Typhimurium ST19 and ST313 strains in mice. For dissemination studies, bacterial burden in organs was determined at various time-points post-challenge. Indian rhesus macaques were infected with one ST19 and one ST313 strain. Animals were monitored for clinical signs and bacterial burden and pathology were determined. The LD50 values for ST19 and ST313 infected mice were not significantly different. However, ST313-infected BALB/c mice had significantly higher bacterial numbers in blood at 24 h than ST19-infected mice. ST19-infected rhesus macaques exhibited moderate-to-severe diarrhea while ST313-infected monkeys showed no-to-mild diarrhea. ST19-infected monkeys had higher bacterial burden and increased inflammation in tissues. Our data suggest that Salmonella Typhimurium ST313 invasiveness may be investigated using mice. The non-human primate results are consistent with clinical data, suggesting that ST313 strains do not cause diarrhea.

Prevalence and Characterization of Oxacillin Susceptible mecA-Positive Clinical Isolates of Staphylococcus aureus Causing Bovine Mastitis in India.

PubMed

Mistry, Hiral; Sharma, Paresh; Mahato, Sudipta; Saravanan, R; Kumar, P Anand; Bhandari, Vasundhra

2016-01-01

Bovine mastitis caused by multidrug resistant Staphylococcus aureus is a huge problem reported worldwide, resulting in prolonged antibiotic treatment and death of livestock. The current study is focused on surveillance of antibiotic susceptibility along with genotypic and phenotypic characterization of the pathogenic S. aureus strains causing mastitis in India. One hundred and sixty seven milk samples were collected from mastitis-affected cows from different farms in India resulting in thirty nine isolated S. aureus strains. Antibiotic sensitivity profiling revealed the majority of the strains (n = 24) to be multidrug resistant and eleven strains showed reduced susceptibility to vancomycin (MICs = 2μg/ml). All strains were oxacillin sensitive, but 19 strains were positive for the mecA gene, which revealed the occurrence of oxacillin susceptible mecA positive strains (OS-MRSA) for the first time from India. Additionally, 32 strains were positive for the pvl gene, a virulence determinant; of these 17 were also OS-MRSA strains. Molecular characterization based on multilocus sequence typing (MLST), spa typing, agr typing and SCCmec classification revealed strains belonging to different groups. Moreover, strains showed spa types (t2526, t9602) and MLST sequence types, ST-72, ST-88 and ST-239 which have been earlier reported in human infections. The prevalence of OS-MRSA strains indicates the importance of including both the genetic and phenotypic tests in characterizing S. aureus strains. Increased genotypic variability with strain related to human infections and pvl positive isolates indicates a worrisome situation with the possibility of bilateral transfer.

Draft Genome Sequence of Enterococcus faecium Strain J19, Isolated from Cabbage

PubMed Central

2018-01-01

ABSTRACT Herein, we report the draft genome sequence of a newly discovered probiotic strain, Enterococcus faecium J19, which was isolated from cabbage. Strain J19 has shown antagonistic effects against the human foodborne pathogen Listeria monocytogenes in coculture and in different food matrices. PMID:29622613

Influenza A Virus Infection Predisposes Hosts to Secondary Infection with Different Streptococcus pneumoniae Serotypes with Similar Outcome but Serotype-Specific Manifestation.

PubMed

Sharma-Chawla, Niharika; Sender, Vicky; Kershaw, Olivia; Gruber, Achim D; Volckmar, Julia; Henriques-Normark, Birgitta; Stegemann-Koniszewski, Sabine; Bruder, Dunja

2016-12-01

Influenza A virus (IAV) and Streptococcus pneumoniae are major causes of respiratory tract infections, particularly during coinfection. The synergism between these two pathogens is characterized by a complex network of dysregulated immune responses, some of which last until recovery following IAV infection. Despite the high serotype diversity of S. pneumoniae and the serotype replacement observed since the introduction of conjugate vaccines, little is known about pneumococcal strain dependency in the enhanced susceptibility to severe secondary S. pneumoniae infection following IAV infection. Thus, we studied how preinfection with IAV alters host susceptibility to different S. pneumoniae strains with various degrees of invasiveness using a highly invasive serotype 4 strain, an invasive serotype 7F strain, and a carrier serotype 19F strain. A murine model of pneumococcal coinfection during the acute phase of IAV infection showed a significantly increased degree of pneumonia and mortality for all tested pneumococcal strains at otherwise sublethal doses. The incidence and kinetics of systemic dissemination, however, remained bacterial strain dependent. Furthermore, we observed strain-specific alterations in the pulmonary levels of alveolar macrophages, neutrophils, and inflammatory mediators ultimately affecting immunopathology. During the recovery phase following IAV infection, bacterial growth in the lungs and systemic dissemination were enhanced in a strain-dependent manner. Altogether, this study shows that acute IAV infection predisposes the host to lethal S. pneumoniae infection irrespective of the pneumococcal serotype, while the long-lasting synergism between IAV and S. pneumoniae is bacterial strain dependent. These results hold implications for developing tailored therapeutic treatment regimens for dual infections during future IAV outbreaks. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Phenotypic, Genotypic, and Antimicrobial Characteristics of Streptococcus halichoeri Isolates from Humans, Proposal To Rename Streptococcus halichoeri as Streptococcus halichoeri subsp. halichoeri, and Description of Streptococcus halichoeri subsp. hominis subsp. nov., a Bacterium Associated with Human Clinical Infections.

PubMed

Shewmaker, P L; Whitney, A M; Humrighouse, B W

2016-03-01

Phenotypic, genotypic, and antimicrobial characteristics of six phenotypically distinct human clinical isolates that most closely resembled the type strain of Streptococcus halichoeri isolated from a seal are presented. Sequencing of the 16S rRNA, rpoB, sodA, and recN genes; comparative whole-genome analysis; conventional biochemical and Rapid ID 32 Strep identification methods; and antimicrobial susceptibility testing were performed on the human isolates, the type strain of S. halichoeri, and type strains of closely related species. The six human clinical isolates were biochemically indistinguishable from each other and showed 100% 16S rRNA, rpoB, sodA, and recN gene sequence similarity. Comparative 16S rRNA gene sequencing analysis revealed 98.6% similarity to S. halichoeri CCUG 48324(T), 97.9% similarity to S. canis ATCC 43496(T), and 97.8% similarity to S. ictaluri ATCC BAA-1300(T). A 3,530-bp fragment of the rpoB gene was 98.8% similar to the S. halichoeri type strain, 84.6% to the S. canis type strain, and 83.8% to the S. ictaluri type strain. The S. halichoeri type strain and the human clinical isolates were susceptible to the antimicrobials tested based on CLSI guidelines for Streptococcus species viridans group with the exception of tetracycline and erythromycin. The human isolates were phenotypically distinct from the type strain isolated from a seal; comparative whole-genome sequence analysis confirmed that the human isolates were S. halichoeri. On the basis of these results, a novel subspecies, Streptococcus halichoeri subsp. hominis, is proposed for the human isolates and Streptococcus halichoeri subsp. halichoeri is proposed for the gray seal isolates. The type strain of the novel subspecies is SS1844(T) = CCUG 67100(T) = LMG 28801(T). Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Identification of potential probiotic starter cultures for Scandinavian-type fermented sausages.

PubMed

Klingberg, Trine Danø; Axelsson, Lars; Naterstad, Kristine; Elsser, Dieter; Budde, Birgitte Bjørn

2005-12-15

Potential probiotic cultures suitable as starter cultures for the Scandinavian-type fermented sausages were identified among strains well-adapted to fermented meats as well as strains originating from a culture collection. From 15 different fermented meat products, 22 strains were isolated as dominant non-starter lactic acid bacteria (NSLAB). The isolates were identified by RAPD, API and sequence analysis of 16S rRNA and showed to be five strains of Lactobacillus sakei, five strains of Lactobacillus farciminis, five strains belonging to the group of Lactobacillus plantarum/pentosus, four strains of Lactobacillus alimentarius, two strains of Lactobacillus brevis and one strain of Lactobacillus versmoldensis. Heterofermentative strains as well as strains not growing at 37 degrees C and not lowering pH below 5.1 in a meat model were excluded leaving 9 strains for further studies. These strains together with 19 strains from a culture collection were evaluated by in vitro methods including survival upon exposure to pH 2.5 or 0.3% oxgall and adhesion to the human colon adenocarcinoma cell line Caco-2 as well as antimicrobial activity against potential pathogens. Strains that fulfilled all the probiotic criteria and showed to be fast acid producers in a meat model included three strains belonging to the group of Lb. plantarum/pentosus (MF1291, MF1298, MF1300) which originated from the dominant NSLAB of fermented meat products. MF1291 and MF 1298 were further identified as Lb. plantarum and MF1300 as Lb. pentosus. The three strains were all successfully applied as starter cultures for the production of fermented sausage. The viable count at the end of the processing period reached high cell numbers (4.7x10(7)-2.9x10(8) cfu/g) and pH of the sausages decreased to pH 4.8-4.9 without any flavour deviation compared to sausage fermented by a commercial meat starter culture.

Lactobacillus gorillae sp. nov., isolated from the faeces of captive and wild western lowland gorillas (Gorilla gorilla gorilla).

PubMed

Tsuchida, Sayaka; Kitahara, Maki; Nguema, Pierre Philippe Mbehang; Norimitsu, Saeko; Fujita, Shiho; Yamagiwa, Juichi; Ngomanda, Alfred; Ohkuma, Moriya; Ushida, Kazunari

2014-12-01

Four strains of Gram-staining-positive, anaerobic rods were isolated from the faeces of western lowland gorillas (Gorilla gorilla gorilla). Three strains, KZ01(T), KZ02 and KZ03, were isolated at the Kyoto City Zoo, Japan, and one strain, GG02, was isolated in the Moukalaba-Doudou National Park, Gabon. These strains were investigated taxonomically. These strains belonged to the Lactobacillus reuteri phylogenetic group according to phylogenetic analysis based on 16S rRNA gene sequences and specific phenotypic characteristics. Phylogenetic analysis of their 16S rRNA gene sequences revealed that strains KZ01(T), KZ02, KZ03 and GG02 formed a single monophyletic cluster and had a distinct line of descent. Based on sequence similarity of the 16S rRNA gene, Lactobacillus fermentum JCM 1173(T) (96.6 %) was the closest neighbour to these novel strains, although it was clear that these strains belonged to a different species. Partial pheS sequences also supported these relationships. DNA-DNA relatedness between strain KZ01(T) and L. fermentum JCM 1173(T) was less than 22 % and the DNA G+C content of strain KZ01(T) was 50.7 mol%. The cell-wall peptidoglycan type was A4β (l-Orn-d-Asp) and the major fatty acids were C16 : 0, C18 : 1ω9c and C19 : 1 cyclo 9,10. Therefore, based on phylogenetic, phenotypic and physiological evidence, these strains represent a novel species of the genus Lactobacillus, for which the name Lactobacillus gorillae sp. nov. is proposed. The type strain is KZ01(T) ( = JCM 19575(T) = DSM 28356(T)). © 2014 IUMS.

Erysipelothrix larvae sp. nov., isolated from the larval gut of the rhinoceros beetle, Trypoxylus dichotomus (Coleoptera: Scarabaeidae).

PubMed

Bang, Byung-Ho; Rhee, Moon-Soo; Chang, Dong-Ho; Park, Doo-Sang; Kim, Byoung-Chan

2015-02-01

A novel, Gram-stain positive, facultative anaerobic, non-motile and straight to curve rod shaped bacterium, strain LV19(T) was isolated from the larval gut of the rhinoceros beetle, Trypoxylus dichotomus, which was collected from Yeong-dong, Chuncheongbuk-do, South Korea. The colonies of the new isolate were convex, circular, cream white in color and 1-2 mm in diameter after 3 days incubation on Tryptic Soy Agar at 37 °C. Based on the 16S rRNA gene sequence similarity, the new isolate was most closely related to Erysipelothrix inopinata MF-EP02(T), E. rhusiopathiae ATCC 19414 (T) and E. tonsillarum T-305(T) (94.8, 93.8 and 93.7 % similarity, respectively). Strain LV19(T) grew optimally at 37 °C, at pH 8.0 and in the presence of 0.5 % (w/v) NaCl. Oxidase activity and catalase activity were negative. The major cellular fatty acids (>10 %) were C18:2 cis-9,12 (28.9 %), C18:1 cis-9 (22.3 %), C16:0 (22.2 %) and C18:0 (18.5 %). The cell-wall hydrolysates contained ribose as a major sugar. Major polar lipids were phosphatidylglycerol and three unidentified glycolipids. No quinone was detected. The G+C content of the genomic DNA was 36.3 mol%. The levels of DNA-DNA relatedness between strain LV19(T) and all the reference strains were less than 20 %. On the basis of polyphasic evidence from this study, the isolate is considered to represent a novel species of the genus Erysipelothrix, for which the name Erysipelothrix larvae sp. nov. is proposed; the type strain is LV19(T) (=KCTC 33523(T) = DSM 28480(T)).

Burkholderia dipogonis sp. nov., isolated from root nodules of Dipogon lignosus in New Zealand and Western Australia.

PubMed

Sheu, Shih-Yi; Chen, Ming-Hui; Liu, Wendy Y Y; Andrews, Mitchell; James, Euan K; Ardley, Julie K; De Meyer, Sofie E; James, Trevor K; Howieson, John G; Coutinho, Bruna G; Chen, Wen-Ming

2015-12-01

Seven strains, ICMP 19430T, ICMP 19429, ICMP 19431, WSM4637, WSM4638, WSM4639 and WSM4640, were isolated from nitrogen-fixing nodules on roots of the invasive South African legume Dipogon lignosus (subfamily Papilionoideae, tribe Phaseoleae) in New Zealand and Western Australia, and their taxonomic positions were investigated by using a polyphasic approach. All seven strains grew at 10-37 °C (optimum, 25-30 °C), at pH 4.0-9.0 (optimum, pH 6.0-7.0) and with 0-2 % (w/v) NaCl (optimum growth in the absence of NaCl). On the basis of 16S rRNA gene sequence analysis, the strains showed 99.0-99.5 % sequence similarity to the closest type strain, Burkholderia phytofirmans PsJNT, and 98.4-99.7 % sequence similarity to Burkholderia caledonica LMG 19076T. The predominant fatty acids were C18 : 1ω7c (21.0 % of the total fatty acids in strain ICMP 19430T), C16 : 0 (19.1 %), C17 : 0 cyclo (18.9 %), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c; 10.7 %) and C19 : 0 cyclov ω8c (7.5 %). The polar lipid profile consisted of a mixture of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and several uncharacterized aminophospholipids and phospholipids. The major isoprenoid quinone was Q-8 and the DNA G+C content of strain ICMP 19430T was 63.2 mol%. The DNA–DNA relatedness of the novel strains with respect to the closest neighbouring members of the genus Burkholderia was 55 % or less. On the basis of 16S rRNA and recA gene sequence similarities and chemotaxonomic and phenotypic data,these strains represent a novel symbiotic species in the genus Burkholderia, for which the name Burkholderia dipogonis sp. nov. is proposed, with the type strain ICMP 19430T (=LMG28415T=HAMBI 3637T).

Diversity of staphylococcal cassette chromosome mec structures in methicillin-resistant Staphylococcus epidermidis and Staphylococcus haemolyticus strains among outpatients from four countries.

PubMed

Ruppé, Etienne; Barbier, François; Mesli, Yasmine; Maiga, Aminata; Cojocaru, Radu; Benkhalfat, Mokhtar; Benchouk, Samia; Hassaine, Hafida; Maiga, Ibrahim; Diallo, Amadou; Koumaré, Abdel Karim; Ouattara, Kalilou; Soumaré, Sambou; Dufourcq, Jean-Baptiste; Nareth, Chhor; Sarthou, Jean-Louis; Andremont, Antoine; Ruimy, Raymond

2009-02-01

In staphylococci, methicillin (meticillin) resistance (MR) is mediated by the acquisition of the mecA gene, which is carried on the size and composition variable staphylococcal cassette chromosome mec (SCCmec). MR has been extensively studied in Staphylococcus aureus, but little is known about MR coagulase-negative staphylococci (MR-CoNS). Here, we describe the diversity of SCCmec structures in MR-CoNS from outpatients living in countries with contrasting environments: Algeria, Mali, Moldova, and Cambodia. Their MR-CoNS nasal carriage rates were 29, 17, 11, and 31%, respectively. Ninety-six MR-CoNS strains, comprising 75 (78%) Staphylococcus epidermidis strains, 19 (20%) Staphylococcus haemolyticus strains, 1 (1%) Staphylococcus hominis strain, and 1 (1%) Staphylococcus cohnii strain, were analyzed. Eighteen different SCCmec types were observed, with 28 identified as type IV (29%), 25 as type V (26%), and 1 as type III (1%). Fifteen strains (44%) were untypeable for their SCCmec. Thirty-four percent of MR-CoNS strains contained multiple ccr copies. Type IV and V SCCmec were preferentially associated with S. epidermidis and S. haemolyticus, respectively. MR-CoNS constitute a widespread and highly diversified MR reservoir in the community.

Freezing and desiccation tolerance in entomopathogenic nematodes: diversity and correlation of traits.

PubMed

Shapiro-Ilan, David I; Brown, Ian; Lewis, Edwin E

2014-03-01

The ability of entomopathogenic nematodes to tolerate environmental stress such as desiccating or freezing conditions, can contribute significantly to biocontrol efficacy. Thus, in selecting which nematode to use in a particular biocontrol program, it is important to be able to predict which strain or species to use in target areas where environmental stress is expected. Our objectives were to (i) compare inter- and intraspecific variation in freeze and desiccation tolerance among a broad array of entomopathogenic nematodes, and (ii) determine if freeze and desiccation tolerance are correlated. In laboratory studies we compared nematodes at two levels of relative humidity (RH) (97% and 85%) and exposure periods (24 and 48 h), and nematodes were exposed to freezing temperatures (-2°C) for 6 or 24 h. To assess interspecific variation, we compared ten species including seven that are of current or recent commercial interest: Heterorhabditis bacteriophora (VS), H. floridensis, H. georgiana, (Kesha), H. indica (HOM1), H. megidis (UK211), Steinernema carpocapsae (All), S. feltiae (SN), S. glaseri (VS), S. rarum (17C&E), and S. riobrave (355). To assess intraspecific variation we compared five strains of H. bacteriophora (Baine, Fl1-1, Hb, Oswego, and VS) and four strains of S. carpocapsae (All, Cxrd, DD136, and Sal), and S. riobrave (355, 38b, 7-12, and TP). S. carpocapsae exhibited the highest level of desiccation tolerance among species followed by S. feltiae and S. rarum; the heterorhabditid species exhibited the least desiccation tolerance and S. riobrave and S. glaseri were intermediate. No intraspecific variation was observed in desiccation tolerance; S. carpocapsae strains showed higher tolerance than all H. bacteriophora or S. riobrave strains yet there was no difference detected within species. In interspecies comparisons, poor freeze tolerance was observed in H. indica, and S. glaseri, S. rarum, and S. riobrave whereas H. georgiana and S. feltiae exhibited the highest freeze tolerance, particularly in the 24-h exposure period. Unlike desiccation tolerance, substantial intraspecies variation in freeze tolerance was observed among H. bacteriophora and S. riobrave strains, yet within species variation was not detected among S. carpocapsae strains. Correlation analysis did not detect a relationship between freezing and desiccation tolerance.

Whole-genome sequence of Erysipelothrix larvae LV19(T) (=KCTC 33523(T)), a useful strain for arsenic detoxification, from the larval gut of the rhinoceros beetle, Trypoxylus dichotomus.

PubMed

Lim, Sooyeon; Rhee, Moon-Soo; Chang, Dong-Ho; Kim, Byoung-Chan

2016-04-10

Erysipelothrix larvae LV19(T) was preliminary isolated from the larval gut of a rhinoceros beetle, Trypoxylus dichotomus in Korea. Here, we present the whole genome sequence of E. larvae LV19(T) strain, which consisted of 2,511,486 base pairs with a GC content of 37.4% and one plasmid. Unlike other Erysipelothrix strains (SY 1027, Fujisawa and ATCC 19414), the arsenic-resistance genes were identified in LV19(T) strain. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparative genome analysis identifies two large deletions in the genome of highly-passaged attenuated Streptococcus agalactiae strain YM001 compared to the parental pathogenic strain HN016.

PubMed

Wang, Rui; Li, Liping; Huang, Yan; Luo, Fuguang; Liang, Wanwen; Gan, Xi; Huang, Ting; Lei, Aiying; Chen, Ming; Chen, Lianfu

2015-11-04

Streptococcus agalactiae (S. agalactiae), also known as group B Streptococcus (GBS), is an important pathogen for neonatal pneumonia, meningitis, bovine mastitis, and fish meningoencephalitis. The global outbreaks of Streptococcus disease in tilapia cause huge economic losses and threaten human food hygiene safety as well. To investigate the mechanism of S. agalactiae pathogenesis in tilapia and develop attenuated S. agalactiae vaccine, this study sequenced and comparatively analyzed the whole genomes of virulent wild-type S. agalactiae strain HN016 and its highly-passaged attenuated strain YM001 derived from tilapia. We performed Illumina sequencing of DNA prepared from strain HN016 and YM001. Sequencedreads were assembled and nucleotide comparisons, single nucleotide polymorphism (SNP) , indels were analyzed between the draft genomes of HN016 and YM001. Clustered regularly interspaced short palindromic repeats (CRISPRs) and prophage were detected and analyzed in different S. agalactiae strains. The genome of S. agalactiae YM001 was 2,047,957 bp with a GC content of 35.61 %; it contained 2044 genes and 88 RNAs. Meanwhile, the genome of S. agalactiae HN016 was 2,064,722 bp with a GC content of 35.66 %; it had 2063 genes and 101 RNAs. Comparative genome analysis indicated that compared with HN016, YM001 genome had two significant large deletions, at the sizes of 5832 and 11,116 bp respectively, resulting in the deletion of three rRNA and ten tRNA genes, as well as the deletion and functional damage of ten genes related to metabolism, transport, growth, anti-stress, etc. Besides these two large deletions, other ten deletions and 28 single nucleotide variations (SNVs) were also identified, mainly affecting the metabolism- and growth-related genes. The genome of attenuated S. agalactiae YM001 showed significant variations, resulting in the deletion of 10 functional genes, compared to the parental pathogenic strain HN016. The deleted and mutated functional genes all encode metabolism- and growth-related proteins, not the known virulence proteins, indicating that the metabolism- and growth-related genes are important for the pathogenesis of S. agalactiae.

Isolation and characterization of a novel nitrobenzene-degrading bacterium with high salinity tolerance: Micrococcus luteus.

PubMed

Zheng, Chunli; Qu, Baocheng; Wang, Jing; Zhou, Jiti; Wang, Jing; Lu, Hong

2009-06-15

Strain Z3 was isolated from nitrobenzene-contaminated sludge. Strain Z3 was able to utilize nitrobenzene as a sole source of carbon, nitrogen and energy under aerobic condition. Based on the morphology, physiological biochemical characteristics, and 16S rDNA sequence, strain Z3 was identified as Micrococcus luteus. Strain Z3 completely degraded nitrobenzene with initial concentration of 100, 150, 200, and 250 mg L(-1) within 70, 96, 120 and 196 h, respectively. Kinetics of nitrobenzene degradation was described using the Andrews equation. The kinetic parameters were as follows: q(max)=1.19 h(-1), K(s)=29.11 mg L(-1), and K(i)=94.00 mg L(-1). Strain Z3 had a high salinity tolerance. It degraded 200 mg L(-1) nitrobenzene completely in 5% NaCl (w/w%). Strain Z3 therefore could be an excellent candidate for the bio-treatment of nitrobenzene industrial wastewaters with high salinity. This is the first report on the degradation of nitrobenzene by M. luteus and the degradation of nitrobenzene achieved in such a high salinity.

Metabolic engineering of Clostridium acetobutylicum for the enhanced production of isopropanol-butanol-ethanol fuel mixture.

PubMed

Jang, Yu-Sin; Malaviya, Alok; Lee, Joungmin; Im, Jung Ae; Lee, Sang Yup; Lee, Julia; Eom, Moon-Ho; Cho, Jung-Hee; Seung, Do Young

2013-01-01

Butanol is considered as a superior biofuel, which is conventionally produced by clostridial acetone-butanol-ethanol (ABE) fermentation. Among ABE, only butanol and ethanol can be used as fuel alternatives. Coproduction of acetone thus causes lower yield of fuel alcohols. Thus, this study aimed at developing an improved Clostridium acetobutylicum strain possessing enhanced fuel alcohol production capability. For this, we previously developed a hyper ABE producing BKM19 strain was further engineered to convert acetone into isopropanol. The BKM19 strain was transformed with the plasmid pIPA100 containing the sadh (primary/secondary alcohol dehydrogenase) and hydG (putative electron transfer protein) genes from the Clostridium beijerinckii NRRL B593 cloned under the control of the thiolase promoter. The resulting BKM19 (pIPA100) strain produced 27.9 g/l isopropanol-butanol-ethanol (IBE) as a fuel alcohols with negligible amount of acetone (0.4 g/l) from 97.8 g/l glucose in lab-scale (2 l) batch fermentation. Thus, this metabolically engineered strain was able to produce 99% of total solvent produced as fuel alcohols. The scalability and stability of BKM19 (pIPA100) were evaluated at 200 l pilot-scale fermentation, which showed that the fuel alcohol yield could be improved to 0.37 g/g as compared to 0.29 g/g obtained at lab-scale fermentation, while attaining a similar titer. To the best of our knowledge, this is the highest titer of IBE achieved and the first report on the large scale fermentation of C. acetobutylicum for IBE production. © 2013 American Institute of Chemical Engineers.

Mutants of Arabidopsis thaliana with decreased amplitude in their phototropic response

NASA Technical Reports Server (NTRS)

Khurana, J. P.; Ren, Z.; Steinitz, B.; Parks, B.; Best, T. R.; Poff, K. L.

1989-01-01

Two mutants of Arabidopsis thaliana have been identified with decreased phototropism to 450-nanometer light. Fluence-response relationships for these strains (ZR8 and ZR19) to single and multiple flashes of light show thresholds, curve shapes, and fluence for maximum curvature in first positive' phototropism which are the same as those of the wild type. Similarly, there is no alteration from the wild type in the kinetics of curvature or in the optimum dark period separating sequential flashes in a multiple flash regimen. In addition, in both strains, gravitropism is decreased compared to the wild type by an amount which is comparable to the decrease in phototropism. Based on reciprocal backcrosses, it appears that the alteration is due to a recessive nuclear mutation. It is suggested that ZR8 and ZR19 represent alterations in some step analogous to an amplifier, downstream of the photoreceptor pigment, and common to both phototropism and gravitropism.

Youth with Type 1 Diabetes Have Worse Strain and Less Pronounced Sex Differences in Early Echocardiographic Markers of Diabetic Cardiomyopathy Compared to Their Normoglycemic Peers: A RESistance to InSulin in Type 1 ANd Type 2 diabetes (RESISTANT) Study

PubMed Central

Bjornstad, Petter; Truong, Uyen; Pyle, Laura; Dorosz, Jennifer L.; Cree-Green, Melanie; Baumgartner, Amy; Coe, Gregory; Regensteiner, Judith G.; Reusch, Jane E.B.; Nadeau, Kristen J.

2016-01-01

Objective Diabetic cardiomyopathy is a major cause of morbidity, but limited data are available on early cardiac abnormalities in type 1 diabetes (T1D). We investigated differences in myocardial strain in adolescents with and without T1D. We hypothesized that adolescents with T1D would have worse strain than their normoglycemic peers, which boys would have worse strain than girls, and that strain would correlate with glycemic control and adipokines. Methods We performed fasting laboratory measures and echocardiograms with speckle tracking to evaluate traditional echocardiographic measures in addition to longitudinal (LS) and circumferential (CS) strain, and in adolescents (15±2 years) with (19 boys; 22 girls) and without (16 boys; 32 girls) type 1 diabetes. Results Compared to controls, adolescents with type 1 diabetes had significantly lower CS (−20.9 vs. −22.7%, p=0.02), but not LS (p=0.83). Boys with T1D had significantly lower LS than girls with T1D (−17.5 vs. −19.7%, p=0.047), adjusted for Tanner stage. The significant sex differences observed in indexed left ventricular mass, left end-diastolic volume, diastolic septal and posterior wall thickness in our controls were lacking in adolescents with T1D. Conclusions Our observations suggest that youth with T1D have worse myocardial strain than normoglycemic peers. In addition, the relatively favorable cardiac profile observed in girls vs. boys in the control group, was attenuated in T1D. These early cardiovascular changes in youth with T1D are concerning and warrant longitudinal and mechanistic studies. PMID:27133451

Evidence for a Role of rpoE in Stressed and Unstressed Cells of Marine Vibrio angustum Strain S14

PubMed Central

Hild, Erika; Takayama, Kathy; Olsson, Rose-Marie; Kjelleberg, Staffan

2000-01-01

We report the cloning, sequencing, and characterization of the rpoE homolog in Vibrio angustum S14. The rpoE gene encodes a protein with a predicted molecular mass of 19.4 kDa and has been demonstrated to be present as a single-copy gene by Southern blot analysis. The deduced amino acid sequence of RpoE is most similar to that of the RpoE homolog of Sphingomonas aromaticivorans, ς24, displaying sequence similarity and identity of 63 and 43%, respectively. Northern blot analysis demonstrated the induction of rpoE 6, 12, and 40 min after a temperature shift to 40°C. An rpoE mutant was constructed by gene disruption. There was no difference in viability during logarithmic growth, stationary phase, or carbon starvation between the wild type and the rpoE mutant strain. In contrast, survival of the mutant was impaired following heat shock during exponential growth, as well as after oxidative stress at 24 h of carbon starvation. The mutant exhibited microcolony formation during optimal growth temperatures (22 to 30°C), and cell area measurements revealed an increase in cell volume of the mutant during growth at 30°C, compared to the wild-type strain. Moreover, outer membrane and periplasmic space protein analysis demonstrated many alterations in the protein profiles for the mutant during growth and carbon starvation, as well as following oxidative stress, in comparison with the wild-type strain. It is thereby concluded that RpoE has an extracytoplasmic function and mediates a range of specific responses in stressed as well as unstressed cells of V. angustum S14. PMID:11092857

Salinisphaera orenii sp. nov., isolated from a solar saltern.

PubMed

Park, Soo-Je; Cha, In-Tae; Kim, So-Jeong; Shin, Kee-Sun; Hong, YoungSoo; Roh, Dong-Hyun; Rhee, Sung-Keun

2012-08-01

A taxonomic study was performed on two isolates, designated strains MK-B5(T) and MK-B7, isolated from sediment of a solar saltern pond in Gomso Bay, Republic of Korea. Comparative 16S rRNA gene sequence analysis showed that strains MK-B5(T) and MK-B7 belong to the Gammaproteobacteria and are related most closely to Salinisphaera shabanensis JCM 11575(T) ( = E1L3A(T)) (96.3 and 96.5% similarity, respectively), Salinisphaera dokdonensis KCCM 90064(T) ( = CL-ES53(T)) (95.6 and 95.6%) and Salinisphaera hydrothermalis JCM 115514(T) ( = EPR70(T)) (95.1 and 95.3%). The level of 16S rRNA gene sequence similarity between strains MK-B5(T) and MK-B7 was 99.8%. The G+C contents of their genomic DNAs were 63.4 and 63.6 mol%, respectively, and the major respiratory quinone was ubiquinone-8. DNA-DNA relatedness between strains MK-B5(T) and MK-B7 was 98%, indicating that the two isolates represent a single species. However, the level of DNA-DNA relatedness between the two isolates and S. shabanensis E1L3A(T) (26.4-30.8%) indicates that they represent a novel species. Strains MK-B5(T) and MK-B7 possessed C(14:0), C(16:0) and C(19:0)ω8c cyclo as major fatty acids. The two isolates were Gram-stain-negative, strictly aerobic, short rod-shaped and motile. They grew at 10-40 °C (optimum, 35-37 °C), at pH 5.0-8.5 (optimum, 7.0-7.5) and with 5-25% (w/v) NaCl (optimum, 15% NaCl). On the basis of phenotypic and phylogenetic analyses, strains MK-B5(T) and MK-B7 are thus considered to represent a novel species of the genus Salinisphaera, for which the name Salinisphaera orenii sp. nov. is proposed. The type strain is MK-B5(T) ( = KCTC 23198(T) = JCM 17073(T)).

Conserved properties of human and bovine prion strains on transmission to guinea pigs

PubMed Central

Safar, Jiri G.; Giles, Kurt; Lessard, Pierre; Letessier, Frederic; Patel, Smita; Serban, Ana; DeArmond, Stephen J.; Prusiner, Stanley B.

2011-01-01

The first transmissions of human prion diseases to rodents used guinea pigs (Gps, Cavia porcellus). Later, transgenic (Tg) mice expressing human or chimeric human/mouse PrP replaced Gps, but the small size of the mouse limits some investigations. To investigate the fidelity of strain-specific prion transmission to Gps, we inoculated “type 1” and “type 2” prion strains into Gps: we measured the incubation times and determined the strain-specified size of the unglycosylated, protease-resistant (r) PrPSc fragment. Prions passaged once in Gps from cases of sporadic (s) Creutzfeldt–Jakob disease (CJD) and Gerstmann-Sträussler-Scheinker (GSS) disease caused by the P102L mutation were used as well as human prions from a variant (v) CJD case, bovine prions from bovine spongiform encephalopathy (BSE), and mouse-passaged scrapie prions. Variant CJD and BSE prions transmitted to all the inoculated Gps with incubation times of 367 ± 4 d and 436 ± 28 d, respectively. On second passage in Gps, vCJD and BSE prions caused disease in 287 ± 4 d and 310 ± 4 d, while sCJD and GSS prions transmitted in 237 ± 4 d and 279 ± 19 d, respectively. Although hamster Sc237 prions transmitted to 2 of 3 Gps after 574 and 792 d, mouse-passaged RML and 301V prion strains, the latter derived from BSE prions, failed to transmit disease to Gps. Those Gps inoculated with vCJD or BSE prions exhibited “type 2” unglycosylated, rPrPSc (19 kDa) while those receiving sCJD or GSS prions displayed “type 1” prions (21 kDa), as determined by Western blotting. Such strain-specific properties were maintained in Gps as well as mice expressing a chimeric human/mouse transgene. Gps may prove particularly useful in further studies of novel human prions such as those causing vCJD. PMID:21727894

Comparative genomics of closely related Salmonella enterica serovar Typhi strains reveals genome dynamics and the acquisition of novel pathogenic elements.

PubMed

Yap, Kien-Pong; Gan, Han Ming; Teh, Cindy Shuan Ju; Chai, Lay Ching; Thong, Kwai Lin

2014-11-20

Typhoid fever is an infectious disease of global importance that is caused by Salmonella enterica subsp. enterica serovar Typhi (S. Typhi). This disease causes an estimated 200,000 deaths per year and remains a serious global health threat. S. Typhi is strictly a human pathogen, and some recovered individuals become long-term carriers who continue to shed the bacteria in their faeces, thus becoming main reservoirs of infection. A comparative genomics analysis combined with a phylogenomic analysis revealed that the strains from the outbreak and carrier were closely related with microvariations and possibly derived from a common ancestor. Additionally, the comparative genomics analysis with all of the other completely sequenced S. Typhi genomes revealed that strains BL196 and CR0044 exhibit unusual genomic variations despite S. Typhi being generally regarded as highly clonal. The two genomes shared distinct chromosomal architectures and uncommon genome features; notably, the presence of a ~10 kb novel genomic island containing uncharacterised virulence-related genes, and zot in particular. Variations were also detected in the T6SS system and genes that were related to SPI-10, insertion sequences, CRISPRs and nsSNPs among the studied genomes. Interestingly, the carrier strain CR0044 harboured far more genetic polymorphisms (83% mutant nsSNPs) compared with the closely related BL196 outbreak strain. Notably, the two highly related virulence-determinant genes, rpoS and tviE, were mutated in strains BL196 and CR0044, respectively, which revealed that the mutation in rpoS is stabilising, while that in tviE is destabilising. These microvariations provide novel insight into the optimisation of genes by the pathogens. However, the sporadic strain was found to be far more conserved compared with the others. The uncommon genomic variations in the two closely related BL196 and CR0044 strains suggests that S. Typhi is more diverse than previously thought. Our study has demonstrated that the pathogen is continually acquiring new genes through horizontal gene transfer in the process of host adaptation, providing novel insight into its unusual genomic dynamics. The understanding of these strains and virulence factors, and particularly the strain that is associated with the large outbreak and the less studied asymptomatic Typhi carrier in the population, will have important impact on disease control.

Antistaphylococcal activity of DX-619, a new des-F(6)-quinolone, compared to those of other agents.

PubMed

Bogdanovich, Tatiana; Esel, Duygu; Kelly, Linda M; Bozdogan, Bülent; Credito, Kim; Lin, Gengrong; Smith, Kathy; Ednie, Lois M; Hoellman, Dianne B; Appelbaum, Peter C

2005-08-01

The in vitro activity of DX-619, a new des-F(6)-quinolone, was tested against staphylococci and compared to those of other antimicrobials. DX-619 had the lowest MIC ranges/MIC(50)s/MIC(90)s (microg/ml) against 131 Staphylococcus aureus strains (32), and ciprofloxacin (>32/>32). Raised quinolone MICs were associated with mutations in GyrA (S84L) and single or double mutations in GrlA (S80F or Y; E84K, G, or V) in all S. aureus strains tested. A recent vancomycin-resistant S. aureus (VRSA) strain (Hershey) was resistant to available quinolones and was inhibited by DX-619 at 0.25 microg/ml and sitafloxacin at 1.0 microg/ml. Vancomycin (except VRSA), linezolid, ranbezolid, tigecycline, and quinupristin-dalfopristin were active against all strains, and teicoplanin was active against S. aureus but less active against coagulase-negative staphylococci. DX-619 produced resistant mutants with MICs of 1 to >32 microg/ml after <50 days of selection compared to 16 to >32 microg/ml for ciprofloxacin, sitafloxacin, moxifloxacin, and gatifloxacin. DX-619 and sitafloxacin were also more active than other tested drugs against selected mutants and had the lowest mutation frequencies in single-step resistance selection. DX-619 and sitafloxacin were bactericidal against six quinolone-resistant (including the VRSA) and seven quinolone-susceptible strains tested, whereas gatifloxacin, moxifloxacin, levofloxacin, and ciprofloxacin were bactericidal against 11, 10, 7, and 5 strains at 4x MIC after 24 h, respectively. DX-619 was also bactericidal against one other VRSA strain, five vancomycin-intermediate S. aureus strains, and four vancomycin-intermediate coagulase-negative staphylococci. Linezolid, ranbezolid, and tigecycline were bacteriostatic and quinupristin-dalfopristin, teicoplanin, and vancomycin were bactericidal against two, eight, and nine strains, and daptomycin and oritavancin were rapidly bactericidal against all strains, including the VRSA. DX-619 has potent in vitro activity against staphylococci, including methicillin-, ciprofloxacin-, and vancomycin-resistant strains.

Spiribacter roseus sp. nov., a moderately halophilic species of the genus Spiribacter from salterns.

PubMed

León, María José; Vera-Gargallo, Blanca; Sánchez-Porro, Cristina; Ventosa, Antonio

2016-10-01

Four pink-pigmented, non-motile, Gram-staining-negative and moderately halophilic curved rods, designated strains SSL50T, SSL25, SSL97 and SSL4, were isolated from a saltern located in Isla Cristina, Huelva, south-west Spain. Phylogenetic analyses based on 16S rRNA gene sequences showed that they were members of the genus Spiribacter, most closely related to Spiribacter curvatus UAH-SP71T (99.3-99.5 % sequence similarity) and Spiribacter salinus M19-40T (96.5-96.7 %). Other related strains were Alkalilimnicola ehrlichii MLHE-1T (95.1-95.3 %), Arhodomonas recens RS91T (95.1-95.2 %) and Arhodomonas aquaeolei ATCC 49307T (95.0-95.1 %), all members of the family Ectothiorhodospiraceae. The major fatty acids were C18 : 1ω6c and/or C18 : 1ω7c, C16 : 0 and C12 : 0. The DNA G+C range was 64.0-66.3 mol%. The DNA-DNA hybridization values between strains SSL50T, SSL25, SSL97, SSL4 and S. piribacter. curvatus UAH-SP71T were 37-49 %. The average nucleotide identity (ANIb) values between the genome of strain SSL50T and those of the two other representatives of the genus Spiribacter, S. curvatus UAH-SP71T and S. salinus M19-40T, were 82.4 % and 79.1 %, respectively, supporting the proposal of a novel species of the genus Spiribacter. On the basis of the polyphasic analysis, the four new isolates are considered to represent a novel species of the genus Spiribacter, for which the name Spiribacter roseus sp. nov. is proposed. The type strain is SSL50T (=CECT 9117T=IBRC-M 11076T).

Methylopila helvetica sp. nov. and Methylobacterium dichloromethanicum sp. nov.--novel aerobic facultatively methylotrophic bacteria utilizing dichloromethane.

PubMed

Doronina, N V; Trotsenko, Y A; Tourova, T P; Kuznetsov, B B; Leisinger, T

2000-06-01

Eight strains of Gram-negative, aerobic, asporogenous, neutrophilic, mesophilic, facultatively methylotrophic bacteria are taxonomically described. These icl- serine pathway methylobacteria utilize dichloromethane, methanol and methylamine as well as a variety of polycarbon compounds as the carbon and energy source. The major cellular fatty acids of the non-pigmented strains DM1, DM3, and DM5 to DM9 are C18:1, C16:0, C18:0, Ccy19:0 and that of the pink-pigmented strain DM4 is C18:1. The main quinone of all the strains is Q-10. The non-pigmented strains have similar phenotypic properties and a high level of DNA-DNA relatedness (81-98%) as determined by hybridization. All strains belong to the alpha-subgroup of the alpha-Proteobacteria. 16S rDNA sequence analysis led to the classification of these dichloromethane-utilizers in the genus Methylopila as a new species - Methylopila helvetica sp.nov. with the type strain DM9 (=VKM B-2189). The pink-pigmented strain DM4 belongs to the genus Methylobacterium but differs from the known members of this genus by some phenotypic properties, DNA-DNA relatedness (14-57%) and 16S rDNA sequence. Strain DM4 is named Methylobacterium dichloromethanicum sp. nov. (VKM B-2191 = DSMZ 6343).

Efficacy of single calfhood vaccination of elk with Brucella abortus strain 19

USGS Publications Warehouse

Roffe, T.J.; Jones, L.C.; Coffin, K.; Drew, M.L.; Sweeney, Steven J.; Hagius, S.D.; Elzer, P.H.; Davis, D.

2004-01-01

Brucellosis has been eradicated from cattle in the states of Wyoming, Montana, and Idaho, USA. However, free-ranging elk (Cervus elaphus) that use feedgrounds in the Greater Yellowstone Area (GYA) and bison (Bison bison) in Yellowstone and Grand Teton national parks still have high seroprevalence to the disease and have caused loss of brucellosis-free status in Wyoming. Management tools to control or eliminate the disease are limited; however, wildlife vaccination is among the methods currently used by wildlife managers in Wyoming. We conducted a controlled challenge study of single calfhood vaccination. Elk calves, caught in January and February of 1999 and 2000 and acclimated to captivity for 3 weeks, were randomly assigned to control or vaccinate groups. The vaccinate groups received Brucetta abortus vaccine strain 19 (S19) by hand-delivered intramuscular injection. Calves were raised to adulthood and bred at either 2.5 or 3.5 years of age for 2000 and 1999 captures, respectively. Eighty-nine (44 controls, 45 vaccinates) pregnant elk entered the challenge portion of the study. We challenged elk at mid-gestation with pathogenic B. abortus strain 2308 by intraconjunctival instillation. Abortion occurred in significantly more (P = 0.002) controls (42; 93%) than vaccinates (32; 71%), and vaccine protected 25% of the vaccinate group. We used Brucella culture of fetus/calf tissues to determine the efficacy of vaccination for preventing infection, and we found that the number of infected fetuses/calves did not differ between controls and vaccinates (P = 0.14). Based on these data, single calfhood vaccination with S19 has low efficacy, will likely have only little to moderate effect on Brucella prevalence in elk, and is unlikely to eradicate the disease in wildlife of the GYA.

Gene knockout and overexpression analysis revealed the role of N-acetylmuramidase in autolysis of Lactobacillus delbrueckii subsp. bulgaricus ljj-6.

PubMed

Pang, Xiao-Yang; Cui, Wen-Ming; Liu, Lu; Zhang, Shu-Wen; Lv, Jia-Ping

2014-01-01

Autolysis of lactic acid bacteria (LAB) plays a vital role in dairy processing. During cheese making, autolysis of LAB affects cheese flavor development through release of intracellular enzymes and restricts the proliferation of cells in yogurt fermentation and probiotics production. In order to explore the mechanism of autolysis, the gene for the autolytic enzymes of L. bulgaricus, N-acetylmuramidase (mur), was cloned and sequenced (GenBank accession number: KF157911). Mur gene overexpression and gene knockout vectors were constructed based on pMG76e and pUC19 vectors. Recombinant plasmids were transformed into L. bulgaricus ljj-6 by electroporation, then three engineered strains with pMG76e-mur vector and fifteen engineered strains with pUC19-mur::EryBII were screened. The autolysis of the mur knockout strain was significantly lower and autolysis of the mur overexpressed strain was significantly higher compared with that of the wild type strain ljj-6. This result suggested that the mur gene played an important role in autolysis of L. bulgaricus. On the other hand, autolytic activity in a low degree was still observed in the mur knockout strain, which implied that other enzymes but autolysin encoded by mur were also involved in autolysis of L. bulgaricus.

Insight into Identification of Acinetobacter Species by Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) in the Clinical Laboratory

NASA Astrophysics Data System (ADS)

Li, Xiuyuan; Tang, Yanyan; Lu, Xinxin

2018-04-01

Currently, the capability of identification for Acinetobacter species using MALDI-TOF MS still remains unclear in clinical laboratories due to certain elusory phenomena. Thus, we conducted this research to evaluate this technique and reveal the causes of misidentification. Briefly, a total of 788 Acinetobacter strains were collected and confirmed at the species level by 16S rDNA and rpoB sequencing, and subsequently compared to the identification by MALDI-TOF MS using direct smear and bacterial extraction pretreatments. Cluster analysis was performed based on the mass spectra and 16S rDNA to reflect the diversity among different species. Eventually, 19 Acinetobacter species were confirmed, including 6 species unavailable in Biotyper 3.0 database. Another novel species was observed, temporarily named A. corallinus. The accuracy of identification for Acinetobacter species using MALDI-TOF MS was 97.08% (765/788), regardless of which pretreatment was applied. The misidentification only occurred on 3 A. parvus strains and 20 strains of species unavailable in the database. The proportions of strains with identification score ≥ 2.000 using direct smear and bacterial extraction pretreatments were 86.04% (678/788) and 95.43% (752/788), χ 2 = 41.336, P < 0.001. The species similar in 16 rDNA were discriminative from the mass spectra, such as A. baumannii & A. junii, A. pittii & A. calcoaceticus, and A. nosocomialis & A. seifertii. Therefore, using MALDI-TOF MS to identify Acinetobacter strains isolated from clinical samples was deemed reliable. Misidentification occurred occasionally due to the insufficiency of the database rather than sample extraction failure. We suggest gene sequencing should be performed when the identification score is under 2.000 even when using bacterial extraction pretreatment. [Figure not available: see fulltext.

Insight into Identification of Acinetobacter Species by Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) in the Clinical Laboratory.

PubMed

Li, Xiuyuan; Tang, Yanyan; Lu, Xinxin

2018-04-09

Currently, the capability of identification for Acinetobacter species using MALDI-TOF MS still remains unclear in clinical laboratories due to certain elusory phenomena. Thus, we conducted this research to evaluate this technique and reveal the causes of misidentification. Briefly, a total of 788 Acinetobacter strains were collected and confirmed at the species level by 16S rDNA and rpoB sequencing, and subsequently compared to the identification by MALDI-TOF MS using direct smear and bacterial extraction pretreatments. Cluster analysis was performed based on the mass spectra and 16S rDNA to reflect the diversity among different species. Eventually, 19 Acinetobacter species were confirmed, including 6 species unavailable in Biotyper 3.0 database. Another novel species was observed, temporarily named A. corallinus. The accuracy of identification for Acinetobacter species using MALDI-TOF MS was 97.08% (765/788), regardless of which pretreatment was applied. The misidentification only occurred on 3 A. parvus strains and 20 strains of species unavailable in the database. The proportions of strains with identification score ≥ 2.000 using direct smear and bacterial extraction pretreatments were 86.04% (678/788) and 95.43% (752/788), χ 2  = 41.336, P < 0.001. The species similar in 16 rDNA were discriminative from the mass spectra, such as A. baumannii & A. junii, A. pittii & A. calcoaceticus, and A. nosocomialis & A. seifertii. Therefore, using MALDI-TOF MS to identify Acinetobacter strains isolated from clinical samples was deemed reliable. Misidentification occurred occasionally due to the insufficiency of the database rather than sample extraction failure. We suggest gene sequencing should be performed when the identification score is under 2.000 even when using bacterial extraction pretreatment. Graphical Abstract ᅟ.

Determination of O:4 antigen-antibody affinity level in O:5 antigen positive and negative variants of Salmonella enterica serovar Typhimurium.

PubMed

Nakai, Yuka; Ito, Akihisa; Ogawa, Yohsuke; Aribam, Swarmistha Devi; Elsheimer-Matulova, Marta; Shiraiwa, Kazumasa; Kisaka, Stevens M B; Hikono, Hirokazu; Nishikawa, Sayaka; Akiba, Masato; Kawahara, Kazuyoshi; Shimoji, Yoshihiro; Eguchi, Masahiro

2017-04-01

Salmonella enterica serovar Typhimurium (S. Typhimurium) has two serological variants: one that expresses the O:5 antigen (1,4,5,12:i:1,2) and one that lacks O:5 antigen (1,4,12:i:1,2). For serotyping, S. Typhimurium is agglutinated by diagnostic O:4 antigen serum. This study was carried out to compare the antigen-antibody affinity of O:4 antigen in S. Typhimurium χ3306 O:5-positive and S. Typhimurium χ3306 O:5-negative strains. The affinity of O:4 antigen with O:4 antigen serum was found to be stronger in the O:5-negative strains compared to O:5-positive strains. Next, we investigated the antigen-antibody affinity of O:4 antigen with O:4 antigen serum in field strains of S. Typhimurium, which showed the same tendency in affinity as seen with S. Typhimurium χ3306 O:5-positive and negative strains. This study suggests that the presence or absence of O:5 antigen causes differences in O:4 agglutination reactions with different field strains of S. Typhimurium. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Probiotic bacteria inhibit the bovine respiratory pathogen Mannheimia haemolytica serotype 1 in vitro.

PubMed

Amat, S; Subramanian, S; Timsit, E; Alexander, T W

2017-05-01

This study evaluated the potential of probiotic bacteria to inhibit growth and cell adhesion of the bovine respiratory pathogen Mannheimia haemoltyica serotype 1. The inhibitory effects of nine probiotic strains (Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus helveticus, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactococcus lactis, Streptococcus thermophilus and two Paenibacillus polymyxa strains) against M. haemolytica were evaluated using a spot-on-lawn method. Probiotic strains were then tested for their adherence to bovine bronchial epithelial (BBE) cells and the ability to displace and compete against M. haemolytica on BBE. Except for S. thermophilus, all probiotic strains inhibited the growth of M. haemolytica, with zones of inhibition ranging between 12 and 19 mm. Lactobacillus strains and Lactococcus lactis displayed greater (P < 0·05) BBE adhesion compared with M. heamolytica (8·3%) and other probiotics (<2·2%). Strains of P. polymyxa and L. acidophilus caused the greatest reduction in M. haemolytica adherence, through both displacement and competition, compared with other probiotics. The results of this study suggest that probiotics may have the potential to colonize the bovine respiratory tract, and exert antagonistic effects against M. haemolytica serotype 1. A common method to control bovine respiratory disease (BRD) in feedlots is through mass medication with antibiotics upon cattle entry (i.e. metaphylaxis). Increasingly, antimicrobial resistance in BRD bacterial pathogens has been observed in feedlots, which may have important implications for cattle health. In this study, probiotic strains were shown to adhere to bovine respiratory cells and inhibit the BRD pathogen M. haemolytica serotype 1 through competition and displacement. Probiotics may therefore offer a mitigation strategy to reduce BRD bacterial pathogens, in place of metaphylactic antimicrobials. © 2017 Her Majesty the Queen in Right of Canada Letters in Applied Microbiology © 2017 The Society for Applied Microbiology Reproduced with the permission of the Minister of Agriculture and Agri-Food Canada.

High-resolution three-dimensional 19F-magnetic resonance imaging of rat lung in situ: evaluation of airway strain in the perfluorocarbon-filled lung.

PubMed

Weigel, Julia K; Steinmann, Daniel; Emerich, Philipp; Stahl, Claudius A; v Elverfeldt, Dominik; Guttmann, Josef

2011-02-01

Perfluorocarbons (PFC) are biologically and chemically inert fluids with high oxygen and CO(2) carrying capacities. Their use as liquid intrapulmonary gas carriers during liquid ventilation has been investigated. We established a method of high resolution 3D-(19)F-MRI of the totally PFC-filled lung. The goal of this study was to investigate longitudinal and circumferential airway strain in the setting of increasing airway pressures on 3D-(19)F-MR images of the PFC-filled lung. Sixteen female Wistar rats were euthanized and the liquid perfluorocarbon FC-84 instilled into their lungs. 3D-(19)F-MRI was performed at various intrapulmonary pressures. Measurements of bronchial length and cross-sectional area were obtained from transversal 2D images for each pressure range. Changes in bronchial area were used to determine circumferential strain, while longitudinal strain was calculated from changes in bronchial length. Our method of 3D-(19)F-MRI allowed clear visualization of the great bronchi. Longitudinal strain increased significantly up to 31.1 cmH(2)O. The greatest strain could be found in the range of low airway pressures. Circumferential strain increased strongly with the initial pressure rise, but showed no significant changes above 10.4 cmH(2)O. Longitudinal strain was generally higher in distal airways, while circumferential strain showed no difference. Analysis of mechanical characteristics showed that longitudinal and circumferential airway expansion occurred in an anisotropic fashion. Whereas longitudinal strain still increased with higher pressures, circumferential strain quickly reached a 'strain limit'. Longitudinal strain was higher in distal bronchi, as dense PFCs gravitate to dependent, in this case to dorso-basal parts of the lung, acting as liquid positive end expiratory pressure.

Differential induction and spread of tau pathology in young PS19 tau transgenic mice following intracerebral injections of pathological tau from Alzheimer’s disease or corticobasal degeneration brains

PubMed Central

Boluda, Susana; Iba, Michiyo; Zhang, Bin; Raible, Kevin M.; Lee, Virginia M-Y.; Trojanowski, John Q.

2015-01-01

Filamentous tau pathologies are hallmark lesions of several neurodegenerative tauopathies including Alzheimer’s disease (AD) and corticobasal degeneration (CBD) which show cell type-specific and topographically distinct tau inclusions. Growing evidence supports templated transmission of tauopathies through functionally interconnected neuroanatomical pathways suggesting that different self-propagating strains of pathological tau could account for the diverse manifestations of neurodegenerative tauopathies. Here, we describe the rapid and distinct cell type-specific spread of pathological tau following intracerebral injections of CBD or AD brain extracts enriched in pathological tau (designated CBD-Tau and AD-Tau, respectively) in young human mutant P301S tau transgenic (Tg) mice (line PS19) ~6–9 months before they show onset of mutant tau transgene-induced tau pathology. At 1 month post-injection of CBD-Tau, tau inclusions developed predominantly in oligodendrocytes of the fimbria and white matter near the injection sites with infrequent intraneuronal tau aggregates. In contrast, injections of AD-Tau in young PS19 mice induced tau pathology predominantly in neuronal perikarya with little or no oligodendrocyte involvement 1 month post-injection. With longer post-injection survival intervals of up to 6 months, CBD-Tau- and AD-Tau-induced tau pathology spread to different brain regions distant from the injection sites while maintaining the cell type-specific pattern noted above. Finally, CA3 neuron loss was detected 3 months post-injection of AD-Tau but not CBD-Tau. Thus, AD-Tau and CBD-Tau represent specific pathological tau strains that spread differentially and may underlie distinct clinical and pathological features of these two tauopathies. Hence, these strains could become targets to develop disease-modifying therapies for CBD and AD. PMID:25534024

Coaggregation between probiotic bacteria and caries-associated strains: an in vitro study.

PubMed

Twetman, Lisa; Larsen, Ulla; Fiehn, Nils-Erik; Stecksén-Blicks, Christina; Twetman, Svante

2009-01-01

To evaluate the in vitro abilities of probiotic bacteria derived from consumer products to coaggregate with caries-associated mutans streptococci. Six lactobacillus strains (L. acidophilus (CCUG 5917), L. plantarum 299v, L. rhamnosus GG and LB21, L. paracasei F19, L. reuteri PTA5289) were cultivated under anaerobic conditions at 37°C in Man Rogosa Sharpe (MSB) broth for 24 h. Four strains of human streptococci (S. mutans Ingbritt, S. mutans (ATCC 25175), S. mutans GS-5, S. sobrinus (ATCC 33478) were similarly grown in Brain Heart Infusion (BHI) broth. A gastrointestinal pathogen (Escherichia coli) was aerobically cultivated on BHI broth as a positive control. After incubation, the bacteria were aerobically harvested, washed, and suspended in 10 mmol/l phosphate-buffered saline (pH 7.2). The probiotic strains were characterized with the API 50 CH system to confirm their identity. Coaggregation was determined by spectrophotometry in mixtures and bacterial suspensions alone after 1, 2, 4, and 24 h and expressed as the aggregation ratio (%). All probiotic strains showed coaggregation abilities with the oral pathogens and the results were strain specific and dependent on time. S. mutans GS-5 exhibited a significantly higher ability to coaggregate with all the probiotic strains than the other mutans streptococci and E. coli. The differences among the probiotic strains were modest with L. acidophilus being the most prone and L. rhamnosus LB21 the least prone to coaggregate with the oral streptococci. The results demonstrated different abilities of lactobacilli-derived probiotic bacteria to coaggregate with selected oral streptococci. Aggregation assays may be a useful complement for screening of probiotic candidates with possible anti-caries properties.

Lactobacillus rhamnosus GG-supplemented formula expands butyrate-producing bacterial strains in food allergic infants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berni Canani, Roberto; Sangwan, Naseer; Stefka, Andrew T.

Dietary intervention with extensively hydrolyzed casein formula supplemented with Lactobacillus rhamnosus GG (EHCF+LGG) accelerates tolerance acquisition in infants with cow’s milk allergy (CMA). We examined whether this effect is attributable, at least in part, to an influence on the gut microbiota. Fecal samples from healthy controls ( n=20) and from CMA infants ( n=19) before and after treatment with EHCF with ( n=12) and without ( n=7) supplementation with LGG were compared by 16S rRNA-based operational taxonomic unit clustering and oligotyping. Differential feature selection and generalized linear model fitting revealed that the CMA infants have a diverse gut microbial communitymore » structure dominated by Lachnospiraceae (20.5±9.7%) and Ruminococcaceae (16.2±9.1%). Blautia, Roseburia and Coprococcus were significantly enriched following treatment with EHCF and LGG, but only one genus, Oscillospira, was significantly different between infants that became tolerant and those that remained allergic. However, most tolerant infants showed a significant increase in fecal butyrate levels, and those taxa that were significantly enriched in these samples, Blautia and Roseburia, exhibited specific strain-level demarcations between tolerant and allergic infants. As a result, our data suggest that EHCF+LGG promotes tolerance in infants with CMA, in part, by influencing the strain-level bacterial community structure of the infant gut.« less

Lactobacillus rhamnosus GG-supplemented formula expands butyrate-producing bacterial strains in food allergic infants

DOE PAGES

Berni Canani, Roberto; Sangwan, Naseer; Stefka, Andrew T.; ...

2015-09-22

Dietary intervention with extensively hydrolyzed casein formula supplemented with Lactobacillus rhamnosus GG (EHCF+LGG) accelerates tolerance acquisition in infants with cow’s milk allergy (CMA). We examined whether this effect is attributable, at least in part, to an influence on the gut microbiota. Fecal samples from healthy controls ( n=20) and from CMA infants ( n=19) before and after treatment with EHCF with ( n=12) and without ( n=7) supplementation with LGG were compared by 16S rRNA-based operational taxonomic unit clustering and oligotyping. Differential feature selection and generalized linear model fitting revealed that the CMA infants have a diverse gut microbial communitymore » structure dominated by Lachnospiraceae (20.5±9.7%) and Ruminococcaceae (16.2±9.1%). Blautia, Roseburia and Coprococcus were significantly enriched following treatment with EHCF and LGG, but only one genus, Oscillospira, was significantly different between infants that became tolerant and those that remained allergic. However, most tolerant infants showed a significant increase in fecal butyrate levels, and those taxa that were significantly enriched in these samples, Blautia and Roseburia, exhibited specific strain-level demarcations between tolerant and allergic infants. As a result, our data suggest that EHCF+LGG promotes tolerance in infants with CMA, in part, by influencing the strain-level bacterial community structure of the infant gut.« less

Both exogenous subclinical hyperthyroidism and short-term overt hypothyroidism affect myocardial strain in patients with differentiated thyroid carcinoma.

PubMed

Abdulrahman, Randa M; Delgado, Victoria; Hoftijzer, Hendrieke C; Ng, Arnold C T; Ewe, See Hooi; Marsan, Nina Ajmone; Holman, Eduard R; Hovens, Guido C; Corssmit, Eleonora P; Romijn, Johannes A; Bax, Jeroen J; Smit, Johannes W A

2011-05-01

The cardiovascular effects of transitions from exogenous subclinical hyperthyroidism to short-term overt hypothyroidism in patients treated for differentiated thyroid carcinoma remain unclear. The present study aims at evaluating the changes in multidirectional myocardial strain using two-dimensional (2D) speckle tracking during this controlled transition from exogenous subclinical hyperthyroidism to overt hypothyroidism. The study included 14 patients with differentiated thyroid carcinoma on thyrotropin suppressive thyroxine substitution who were subsequently withdrawn from thyroxine for 4 weeks. Cardiac function was assessed by 2D speckle tracking echocardiography before and 1 and 4 weeks after withdrawal and compared with values obtained in a control group of 24 individuals. At baseline, the left ventricular dimensions were significantly higher in patients as compared with controls. Using 2D speckle tracking imaging, the patients had significantly impaired baseline myocardial systolic function in the circumferential (-16.0% ± 2.1% vs. -19.2% ± 3.0%, p = 0.001) and longitudinal (-17.1% ± 2.5% vs. -19.7% ± 3.0%, p = 0.001) directions as compared with controls. Withdrawal of thyroid hormone did not induce significant changes in left ventricular dimensions or systolic function. During the transition from exogenous subclinical hyperthyroidism to overt hypothyroidism, a significant improvement in circumferential and longitudinal systolic shortening was observed and returned to abnormal values when the patients were overt hypothyroid (circumferential strain: from -16.0% ± 2.1% to -18.6% ± 1.9% and -14.7% ± 2.8%, p < 0.005; longitudinal strain: from -17.1% ± 2.5% to -18.8% ± 1.4% and -16.3% ± 1.3%, p < 0.005). A U-shaped relationship between a range of thyroid hormone levels (from hyper- to hypothyroid concentrations) and myocardial strains was observed. The clinical consequences of these findings remain to be determined but may point out an increased myocardial vulnerability even in states of moderate subclinical hyperthyroidism and short-term hypothyroidism.

Bioethanol production by a xylan fermenting thermophilic isolate Clostridium strain DBT-IOC-DC21.

PubMed

Singh, Nisha; Puri, Munish; Tuli, Deepak K; Gupta, Ravi P; Barrow, Colin J; Mathur, Anshu S

2018-06-01

To overcome the challenges associated with combined bioprocessing of lignocellulosic biomass to biofuel, finding good organisms is essential. An ethanol producing bacteria DBT-IOC-DC21 was isolated from a compost site via preliminary enrichment culture on a pure hemicellulosic substrate and identified as a Clostridium strain by 16S rRNA analysis. This strain presented broad substrate spectrum with ethanol, acetate, lactate, and hydrogen as the primary metabolic end products. The optimum conditions for ethanol production were found to be an initial pH of 7.0, a temperature of 70 °C and an L-G ratio of 0.67. Strain presented preferential hemicellulose fermentation when compared to various substrates and maximum ethanol concentration of 26.61 mM and 43.63 mM was produced from xylan and xylose, respectively. During the fermentation of varying concentration of xylan, a substantial amount of ethanol ranging from 25.27 mM to 67.29 mM was produced. An increased ethanol concentration of 40.22 mM was produced from a mixture of cellulose and xylan, with a significant effect observed on metabolic flux distribution. The optimum conditions were used to produce ethanol from 28 g L -1 rice straw biomass (RSB) (equivalent to 5.7 g L -1 of the xylose equivalents) in which 19.48 mM ethanol production was achieved. Thus, Clostridium strain DBT-IOC-DC21 has the potential to perform direct microbial conversion of untreated RSB to ethanol at a yield comparative to xylan fermentation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Spall fracture in aluminium alloy at high strain rates

NASA Astrophysics Data System (ADS)

Joshi, K. D.; Rav, Amit; Sur, Amit; Kaushik, T. C.; Gupta, Satish C.

2016-05-01

Spall fracture strength and dynamic yield strength has been measured in 8mm thick target plates of aluminium alloy Al2024-T4 at high strain rates generated in three plate impact experiments carried out at impact velocities of 180 m/s, 370 m/s and 560m/s, respectively, using single stage gas gun facility. In each experiment, the free surface velocity history of the Al2024-T4 sample plate measured employing velocity interferometer system for any reflector (VISAR) is used to determine the spall strength and dynamic yield strength of this material. The spall strength of 1.11 GPa, 1.16 GPa and 1.43 GPa, determined from measured free surface velocity history of sample material in three experiments performed at impact velocity of 180 m/s, 370 m/s and 560 m/s, respectively, are higher than the quasi static value of 0.469 GPa and display almost linearly increasing trend with increasing impact velocity or equivalently with increasing strain rates. The average strain rates just ahead of the spall fracture are determined to be 1.9×10 4/s, 2.0×104/s and 2.5×104/s, respectively. The dynamic yield strength determined in the three experiments range from 0.383 GPa to 0.407 GPa, which is higher than the quasi static value of 0.324GPa.

Comparative proteome analysis of two Streptococcus agalactiae strains from cultured tilapia with different virulence.

PubMed

Li, Wei; Su, You-Lu; Mai, Yong-Zhan; Li, Yan-Wei; Mo, Ze-Quan; Li, An-Xing

2014-05-14

Streptococcus agalactiae is a major piscine pathogen, which causes significant morbidity and mortality among numerous fish species, and results in huge economic losses to aquaculture. Many S. agalactiae strains showing different virulence characteristics have been isolated from infected tilapia in different geographical regions throughout South China in the recent years, including natural attenuated S. agalactiae strain TFJ0901 and virulent S. agalactiae strain THN0901. In the present study, survival of tilapia challenged with S. agalactiae strain TFJ0901 and THN0901 (10(7)CFU/fish) were 93.3% and 13.3%, respectively. Moreover, there are severe lesions of the examined tissues in tilapia infected with strain THN0901, but no significant histopathological changes were observed in tilapia infected with the strain TFJ0901. In order to elucidate the factors responsible for the invasive potential of S. agalactiae between two strains TFJ0901 and THN0901, a comparative proteome analysis was applied to identify the different protein expression profiles between the two strains. 506 and 508 cellular protein spots of S. agalactiae TFJ0901 and THN0901 were separated by two dimensional electrophoresis, respectively. And 34 strain-specific spots, corresponding to 27 proteins, were identified successfully by MALDI-TOF mass spectrometry. Among them, 23 proteins presented exclusively in S. agalactiae TFJ0901 or THN0901, and the other 4 proteins presented in different isomeric forms between TFJ0901 and THN0901. Most of the strain-specific proteins were just involved in metabolic pathways, while 7 of them were presumed to be responsible for the virulence differences of S. agalactiae strain TFJ0901 and THN0901, including molecular chaperone DnaJ, dihydrolipoamide dehydrogenase, thioredoxin, manganese-dependent inorganic pyrophosphatase, elongation factor Tu, bleomycin resistance protein and cell division protein DivIVA. These virulence-associated proteins may contribute to identify new diagnostic markers and help to understand the pathogenesis of S. agalactiae. Copyright © 2014 Elsevier B.V. All rights reserved.

Comparative study on fermentation performance in the genome shuffled Candida versatilis and wild-type salt tolerant yeast strain.

PubMed

Qi, Wei; Guo, Hong-Lian; Wang, Chun-Ling; Hou, Li-Hua; Cao, Xiao-Hong; Liu, Jin-Fu; Lu, Fu-Ping

2017-01-01

The fermentation performance of a genome-shuffled strain of Candida versatilis S3-5, isolated for improved tolerance to salt, and wild-type (WT) strain were analysed. The fermentation parameters, such as growth, reducing sugar, ethanol, organic acids and volatile compounds, were detected during soy sauce fermentation process. The results showed that ethanol produced by the genome shuffled strain S3-5 was increasing at a faster rate and to a greater extent than WT. At the end of the fermentation, malic acid, citric acid and succinic acid formed in tricarboxylic acid cycle after S3-5 treatment elevated by 39.20%, 6.85% and 17.09% compared to WT, respectively. Moreover, flavour compounds such as phenethyl acetate, ethyl vanillate, ethyl acetate, isoamyl acetate, ethyl myristate, ethyl pentadecanoate, ethyl palmitate and phenylacetaldehyde produced by S3-5 were 2.26, 2.12, 2.87, 34.41, 6.32, 13.64, 2.23 and 78.85 times as compared to WT. S3-5 exhibited enhanced metabolic ability as compared to the wild-type strain, improved conversion of sugars to ethanol, metabolism of organic acid and formation of volatile compounds, especially esters, Moreover, S3-5 might be an ester-flavour type salt-tolerant yeast. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Bovine origin Staphylococcus aureus: A new zoonotic agent?

PubMed

Rao, Relangi Tulasi; Jayakumar, Kannan; Kumar, Pavitra

2017-10-01

The study aimed to assess the nature of animal origin Staphylococcus aureus strains. The study has zoonotic importance and aimed to compare virulence between two different hosts, i.e., bovine and ovine origin. Conventional polymerase chain reaction-based methods used for the characterization of S. aureus strains and chick embryo model employed for the assessment of virulence capacity of strains. All statistical tests carried on R program, version 3.0.4. After initial screening and molecular characterization of the prevalence of S. aureus found to be 42.62% in bovine origin samples and 28.35% among ovine origin samples. Meanwhile, the methicillin-resistant S. aureus prevalence is found to be meager in both the hosts. Among the samples, only 6.8% isolates tested positive for methicillin resistance. The biofilm formation quantified and the variation compared among the host. A Welch two-sample t -test found to be statistically significant, t=2.3179, df=28.103, and p=0.02795. Chicken embryo model found effective to test the pathogenicity of the strains. The study helped to conclude healthy bovines can act as S. aureus reservoirs. Bovine origin S. aureus strains are more virulent than ovine origin strains. Bovine origin strains have high probability to become zoonotic pathogen. Further, gene knock out studies may be conducted to conclude zoonocity of the bovine origin strains.

Comparative genomics identifies distinct lineages of S. Enteritidis from Queensland, Australia.

PubMed

Graham, Rikki M A; Hiley, Lester; Rathnayake, Irani U; Jennison, Amy V

2018-01-01

Salmonella enterica is a major cause of gastroenteritis and foodborne illness in Australia where notification rates in the state of Queensland are the highest in the country. S. Enteritidis is among the five most common serotypes reported in Queensland and it is a priority for epidemiological surveillance due to concerns regarding its emergence in Australia. Using whole genome sequencing, we have analysed the genomic epidemiology of 217 S. Enteritidis isolates from Queensland, and observed that they fall into three distinct clades, which we have differentiated as Clades A, B and C. Phage types and MLST sequence types differed between the clades and comparative genomic analysis has shown that each has a unique profile of prophage and genomic islands. Several of the phage regions present in the S. Enteritidis reference strain P125109 were absent in Clades A and C, and these clades also had difference in the presence of pathogenicity islands, containing complete SPI-6 and SPI-19 regions, while P125109 does not. Antimicrobial resistance markers were found in 39 isolates, all but one of which belonged to Clade B. Phylogenetic analysis of the Queensland isolates in the context of 170 international strains showed that Queensland Clade B isolates group together with the previously identified global clade, while the other two clades are distinct and appear largely restricted to Australia. Locally sourced environmental isolates included in this analysis all belonged to Clades A and C, which is consistent with the theory that these clades are a source of locally acquired infection, while Clade B isolates are mostly travel related.

Immunological response to Brucella abortus strain 19 vaccination of cattle in a communal area in South Africa.

PubMed

Simpson, Gregory J G; Marcotty, Tanguy; Rouille, Elodie; Chilundo, Abel; Letteson, Jean-Jacques; Godfroid, Jacques

2018-03-29

Brucellosis is of worldwide economic and public health importance. Heifer vaccination with live attenuated Brucella abortus strain 19 (S19) is the cornerstone of control in low- and middle-income countries. Antibody persistence induced by S19 is directly correlated with the number of colony-forming units (CFU) per dose. There are two vaccination methods: a 'high' dose (5-8 × 1010 CFU) subcutaneously injected or one or two 'low' doses (5 × 109 CFU) through the conjunctival route. This study aimed to evaluate serological reactions to the 'high' dose and possible implications of the serological findings on disease control. This study included 58 female cases, vaccinated at Day 0, and 29 male controls. Serum was drawn repeatedly and tested for Brucella antibodies using the Rose Bengal Test (RBT) and an indirect enzyme-linked immunosorbent assay (iELISA). The cases showed a rapid antibody response with peak RBT positivity (98%) at 2 weeks and iELISA (95%) at 8 weeks, then decreased in an inverse logistic curve to 14% RBT and 32% iELISA positive at 59 weeks and at 4.5 years 57% (4/7 cases) demonstrated a persistent immune response (RBT, iELISA or Brucellin skin test) to Brucella spp. Our study is the first of its kind documenting the persistence of antibodies in an African communal farming setting for over a year to years after 'high' dose S19 vaccination, which can be difficult to differentiate from a response to infection with wild-type B. abortus. A recommendation could be using a 'low' dose or different route of vaccination.

Evolution of antimicrobial resistance and serotype distribution of Streptococcus pneumoniae isolated from children with invasive and noninvasive pneumococcal diseases in Algeria from 2005 to 2012

PubMed Central

Ramdani-Bouguessa, N.; Ziane, H.; Bekhoucha, S.; Guechi, Z.; Azzam, A.; Touati, D.; Naim, M.; Azrou, S.; Hamidi, M.; Mertani, A.; Laraba, A.; Annane, T.; Kermani, S.; Tazir, M.

2015-01-01

Pneumococcal infections are a major cause of morbidity and mortality in developing countries. The introduction of pneumococcal conjugate vaccines (PCVs) has dramatically reduced the incidence of pneumococcal diseases. PCVs are not currently being used in Algeria. We conducted a prospective study from 2005 to 2012 in Algeria to determine antimicrobial drug resistance and serotype distribution of Streptococcus pneumoniae from children with pneumococcal disease. Among 270 isolated strains from children, 97 (36%) were invasive disease; of these, 48% were not susceptible to penicillin and 53% not susceptible to erythromycin. A high rate of antimicrobial nonsusceptibility was observed in strains isolated from children with meningitis. The serotype distribution from pneumococci isolated from children with invasive infections was (by order of prevalence): 14, 1, 19F, 19A, 6B, 5, 3, 6A and 23F. Multidrug resistance was observed in serotypes 14, 19F, 19A and 6B. The vaccine coverage of serotypes isolated from children aged <5 years was 55.3% for PCV7, 71.1% for PCV10 and 86.8% for PCV13. Our results highlight the burden of pneumococcal disease in Algeria and the increasing S. pneumoniae antibiotic resistance. The current pneumococcal vaccines cover a high percentage of the circulating strains. Therefore, vaccination would reduce the incidence of pneumococcal disease in Algeria. PMID:26106481

Higher Drop in Speed during a Repeated Sprint Test in Soccer Players Reporting Former Hamstring Strain Injury

PubMed Central

Røksund, Ola D.; Kristoffersen, Morten; Bogen, Bård E.; Wisnes, Alexander; Engeseth, Merete S.; Nilsen, Ann-Kristin; Iversen, Vegard V.; Mæland, Silje; Gundersen, Hilde

2017-01-01

Aim: Hamstring strain injury is common in soccer. The aim of this study was to evaluate the physical capacity of players who have and have not suffered from hamstring strain injury in a sample of semi-professional and professional Norwegian soccer players in order to evaluate characteristics and to identify possible indications of insufficient rehabilitation. Method: Seventy-five semi-professional and professional soccer players (19 ± 3 years) playing at the second and third level in the Norwegian league participated in the study. All players answered a questionnaire, including one question about hamstring strain injury (yes/no) during the previous 2 years. They also performed a 40 m maximal sprint test, a repeated sprint test (8 × 20 m), a countermovement jump, a maximal oxygen consumption (VO2max) test, strength tests and flexibility tests. Independent sample t-tests were used to evaluate differences in the physical capacity of the players who had suffered from hamstring strain injury and those who had not. Mixed between-within subject's analyses of variance was used to compare changes in speed during the repeated sprint test between groups. Results: Players who reported hamstring strain injury during the previous two years (16%) had a significantly higher drop in speed (0.07 vs. 0.02 s, p = 0.007) during the repeated sprint test, compared to players reporting no previous hamstring strain injury. In addition, there was a significant interaction (groups × time) (F = 3.22, p = 0.002), showing that speed in the two groups changed differently during the repeated sprint test. There were no significant differences in relations to age, weight, height, body fat, linear speed, countermovement jump height, leg strength, VO2max, or hamstring flexibility between the groups. Conclusion: Soccer players who reported hamstring strain injury during the previous 2 years showed significant higher drop in speed during the repeated sprint test compared to players with no hamstring strain injury. The maximal speed, leg strength, ability to produce maximal power, endurance capacity, and hamstring flexibility was similar for both groups. Thus, a repeated sprint test consisting of 8 × 20 m could be used as a field-based diagnostic tool to identify players in need of reconditioning programs to ensure complete post-injury rehabilitation. PMID:28190999

Autolytic activity and molecular characteristics of Staphylococcus haemolyticus strains with induced vancomycin resistance.

PubMed

Kim, Jung Wook; Chung, Gyung Tae; Yoo, Jung Sik; Lee, Yeong Seon; Yoo, Jae Il

2012-10-01

The aim of this study was to investigate the molecular characteristics of induced vancomycin resistance in Staphylococcus haemolyticus. Autolytic properties and phenotypic characteristics of passage-selected vancomycin-resistant S. haemolyticus strains were examined. In addition, expression of autolysis-related genes (atl, lrgAB, sarA and lytS) was investigated using the RNase protection assay (RPA). The RPA results indicated that only the expression of the atl gene was significantly upregulated (2.5- to 6-fold increase) in vancomycin-intermediate and vancomycin-resistant strains. The vancomycin-resistant strains exhibited lower expression of murein hydrolase proteins and reduced autolytic activity compared with the parent strain. In addition, a reduced growth rate, cell wall thickening and higher survival rate in the presence of lysostaphin were observed in vancomycin-intermediate and vancomycin-resistant induced strains compared with the parent strain. In conclusion, altered autolytic properties, in particular upregulation of the atl gene, may contribute to vancomycin resistance in S. haemolyticus.

Halomonas titanicae sp. nov., a halophilic bacterium isolated from the RMS Titanic.

PubMed

Sánchez-Porro, Cristina; Kaur, Bhavleen; Mann, Henrietta; Ventosa, Antonio

2010-12-01

A Gram-negative, heterotrophic, aerobic, non-endospore-forming, peritrichously flagellated and motile bacterial strain, designated BH1(T), was isolated from samples of rusticles, which are formed in part by a consortium of micro-organisms, collected from the RMS Titanic wreck site. The strain grew optimally at 30-37°C, pH 7.0-7.5 and in the presence of 2-8 % (w/v) NaCl. We carried out a polyphasic taxonomic study in order to characterize the strain in detail. Phylogenetic analyses based on 16S rRNA gene sequence comparison indicated that strain BH1(T) clustered within the branch consisting of species of Halomonas. The most closely related type strains were Halomonas neptunia (98.6 % 16S rRNA sequence similarity), Halomonas variabilis (98.4 %), Halomonas boliviensis (98.3 %) and Halomonas sulfidaeris (97.5 %). Other closely related species were Halomonas alkaliphila (96.5 % sequence similarity), Halomonas hydrothermalis (96.3 %), Halomonas gomseomensis (96.3 %), Halomonas venusta (96.3 %) and Halomonas meridiana (96.2 %). The major fatty acids of strain BH1(T) were C(18 : 1)ω7c (36.3 %), C(16 : 0) (18.4 %) and C(19 : 0) cyclo ω8c (17.9 %). The DNA G+C content was 60.0 mol% (T(m)). Ubiquinone 9 (Q-9) was the major lipoquinone. The phenotypic features, fatty acid profile and DNA G+C content further supported the placement of strain BH1(T) in the genus Halomonas. DNA-DNA hybridization values between strain BH1(T) and H. neptunia CECT 5815(T), H. variabilis DSM 3051(T), H. boliviensis DSM 15516(T) and H. sulfidaeris CECT 5817(T) were 19, 17, 30 and 29 %, respectively, supporting the differential taxonomic status of BH1(T). On the basis of the phenotypic, chemotaxonomic and phylogenetic data, strain BH1(T) is considered to represent a novel species, for which the name Halomonas titanicae sp. nov. is proposed. The type strain is BH1(T) (=ATCC BAA-1257(T) =CECT 7585(T) =JCM 16411(T) =LMG 25388(T)).

Improvement in Strain Concordance between Two Major Vendors after the Strain Standardization Initiative.

PubMed

Yang, Hong; Marwick, Thomas H; Fukuda, Nobuaki; Oe, Hiroki; Saito, Makoto; Thomas, James D; Negishi, Kazuaki

2015-06-01

Disagreement of strain measurements among different vendors has provided an obstacle to the clinical use of strain. A joint standardization task force between professional societies and industry was initiated to reduce intervendor variability of strain. Although feedback from this process has been used in software upgrades, little is known about the effects of efforts to improve conformity. The aim of this study was to assess whether intervendor agreement for global longitudinal strain (GLS) has improved after standardization initiatives. Eighty-two subjects (mean age, 52 ± 21 years; 55% men) prospectively underwent two sequential examinations using two most common ultrasound systems (Vivid E9 and iE33). GLS was calculated using proprietary software (EchoPAC-PC BT12 [E12] and BT13 [E13] vs QLAB version 8.0 [Q8], QLAB version 9.0 [Q9], and QLAB version 10.0 [Q10]). Agreements in GLS were evaluated with Bland-Altman plots. Coefficients of variation (CVs) were compared using the Friedman test and compared with CVs of left ventricular volumes and ejection fraction (LVEF). Median GLS using E12 was -19.2% (interquartile range [IQR], -15.2% to -23.2%), compared with -19.3% (IQR, -14.9% to -23.7%) for E13, -15.7% (IQR, -11.4% to -20%) for Q8, -19% (IQR, -15.7% to -22.3%) for Q9, and -18.7% (IQR, -15.7% to -21.7%) for Q10. The CVs of prestandardization GLS (12 ± 8% [E12/Q8] and 14 ± 8 [E13/Q8]) were significantly larger than that of LVEF (5 ± 5) (P < .001). Since standardization, the CVs of GLS have shown improvement (6 ± 4 [E12/Q9], 7 ± 4 [E12/Q10], 6 ± 4 [E13/Q9], and 7 ± 4 [E13/Q10]) and are similar to those of LVEF. Subsequent to the joint standardization task force, there has been improvement in between-vendor concordance in GLS between two leading ultrasound manufactures, the variability of which is now analogous to that of LVEF. The removal of concerns about measurement variability should allow wider use of GLS. Copyright © 2015 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

Fracture and Plasticity Characterization of DH-36 Navy Steel

DTIC Science & Technology

2012-06-01

32 Figure 30: Butterfly shear test showing front and back views and highlighting the unwanted edge buckling and fracture...maximum point of equivalent plastic strain in the edge section not the gage section. The face shown is the middle of the specimen...0 100 200 300 400 500 600 700 800 900 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 T ru e S tr e ss Plastic Strain Experiment Power Law 19 Figure 12

Early microbial colonization of cystic fibrosis patients identified by neonatal screening, with emphasis on Staphylococcus aureus.

PubMed

Souza, Helena A P H M; Nogueira, Keite S; Matos, Adriana P; Vieira, Ricardo P; Riedi, Carlos A; Rosário, Nelson A; Telles, Flávio Q; Costa, Libera M Dalla

2006-01-01

To assess bacterial colonization prospectively in patients with cystic fibrosis identified by neonatal screening. To assess susceptibility to antimicrobials and to perform the molecular typing of Staphylococcus aureus strains isolated from the oropharynx of patients during the study. Twenty-five cystic fibrosis patients receiving regular treatment at the Cystic Fibrosis Outpatient Clinic of Hospital de Clínicas of Universidade Federal do Paraná, Brazil, were included in the study. All patients were identified by trypsin-like immunoreactivity and their diagnosis was confirmed by two or more sweat tests. Oropharyngeal swabs were collected and cultured according to routine methods; bacterial colonies were phenotypically identified and their susceptibility to antimicrobials was tested. S. aureus isolates were submitted to molecular typing using pulsed-field gel electrophoresis. Out of 234 oropharyngeal swabs, S. aureus was the most frequently isolated strain (76% of patients, 42% of swabs), followed by Pseudomonas aeruginosa (36% of patients, 16% of swabs) and Haemophilus spp. (76% of patients; 19% of swabs). Seventy-three isolates were obtained from 19 patients colonized with S. aureus, of which 18 were oxacillin-resistant (24.6%), isolated from two patients, with the same electrophoretic profiles as that of the Brazilian clone. The remaining oxacillin-sensitive isolates were distributed into 18 electrophoretic profiles. There was higher prevalence of S. aureus, with earlier isolation than other pathogens. Multi-sensitive isolates were distributed into different clones, characterizing non-transmissibility among community-acquired strains. The isolated oxacillin-resistant S. aureus showed identical electrophoretic profiles, probably acquired in hospital. P. aeruginosa was not so frequent in the studied population.

A Zebrafish Larval Model to Assess Virulence of Porcine Streptococcus suis Strains.

PubMed

Zaccaria, Edoardo; Cao, Rui; Wells, Jerry M; van Baarlen, Peter

2016-01-01

Streptococcus suis is an encapsulated Gram-positive bacterium, and the leading cause of sepsis and meningitis in young pigs resulting in considerable economic losses in the porcine industry. It is also considered an emerging zoonotic agent. In the environment, both avirulent and virulent strains occur in pigs, and virulent strains appear to cause disease in both humans and pigs. There is a need for a convenient, reliable and standardized animal model to assess S. suis virulence. A zebrafish (Danio rerio) larvae infection model has several advantages, including transparency of larvae, low cost, ease of use and exemption from ethical legislation up to 6 days post fertilization, but has not been previously established as a model for S. suis. Microinjection of different porcine strains of S. suis in zebrafish larvae resulted in highly reproducible dose- and strain-dependent larval death, strongly correlating with presence of the S. suis capsule and to the original virulence of the strain in pigs. Additionally we compared the virulence of the two-component system mutant of ciaRH, which is attenuated for virulence in both mice and pigs in vivo. Infection of larvae with the ΔciaRH strain resulted in significantly higher survival rate compared to infection with the S10 wild-type strain. Our data demonstrate that zebrafish larvae are a rapid and reliable model to assess the virulence of clinical porcine S. suis isolates.

A Zebrafish Larval Model to Assess Virulence of Porcine Streptococcus suis Strains

PubMed Central

Zaccaria, Edoardo; Cao, Rui; Wells, Jerry M.; van Baarlen, Peter

2016-01-01

Streptococcus suis is an encapsulated Gram-positive bacterium, and the leading cause of sepsis and meningitis in young pigs resulting in considerable economic losses in the porcine industry. It is also considered an emerging zoonotic agent. In the environment, both avirulent and virulent strains occur in pigs, and virulent strains appear to cause disease in both humans and pigs. There is a need for a convenient, reliable and standardized animal model to assess S. suis virulence. A zebrafish (Danio rerio) larvae infection model has several advantages, including transparency of larvae, low cost, ease of use and exemption from ethical legislation up to 6 days post fertilization, but has not been previously established as a model for S. suis. Microinjection of different porcine strains of S. suis in zebrafish larvae resulted in highly reproducible dose- and strain-dependent larval death, strongly correlating with presence of the S. suis capsule and to the original virulence of the strain in pigs. Additionally we compared the virulence of the two-component system mutant of ciaRH, which is attenuated for virulence in both mice and pigs in vivo. Infection of larvae with the ΔciaRH strain resulted in significantly higher survival rate compared to infection with the S10 wild-type strain. Our data demonstrate that zebrafish larvae are a rapid and reliable model to assess the virulence of clinical porcine S. suis isolates. PMID:26999052

Identification and Characterization of a Gene stp17 Located on the Linear Plasmid pBSSB1 as an Enhanced Gene of Growth and Motility in Salmonella enterica Serovar Typhi

PubMed Central

Zhang, Haifang; Zhu, Yunxia; Xie, Xiaofang; Wang, Min; Du, Hong; Xu, Shungao; Zhang, Ying; Gong, Mingyu; Ni, Bin; Xu, Huaxi; Huang, Xinxiang

2016-01-01

The linear plasmid pBSSB1 mediates the flagellar phase variation in H:z66 positive Salmonella enterica serovar Typhi (S. Typhi). The gene named stp17 (S. Typhi plasmid number 17 gene) is located on pBSSB1 and encodes the protein STP17. The expression pattern at the protein-level and function of STP17 remains unknown. In this study, the recombinant protein STP17His6 was expressed, purified and used to prepare the polyclonal anti-STP17 antibody. We detected protein-level expression of stp17 in S. Typhi and further investigated the protein expression characteristics of stp17 in different growth phases by western blot analysis. The effects of STP17 on bacterial growth and motility were analyzed. In addition, the structure of STP17 was predicted and the active site of STP17 was identified by site-directed mutagenesis. The results showed that STP17 was expressed stably in the wild type strain of S. Typhi. STP17 expression at the protein level peaks when cultures reach an OD600 value of 1.2. The growth rate and motility of the Δstp17 strain were significantly decreased compared with the wild type strain (P < 0.05) and this phenotype was restored in the stp17 complementary strain. Moreover, the growth rate and motility of the stp17 over-expression strain was greater than the wild type strain. STP17 contains nine Helix segments, six Stand segments and some Coil segments in the secondary structural level. The top-ranked 3-D structure of STP17 predicted by I-TASSER contains a putative ATPase domain and the amino acid residues of GLY16, GLY19, LYS20, ASN133, LYS157, and LYS158 may be the active site residues of STP17. Finally, STP17 was able to catalyze the ATP to ADP reaction, suggesting that STP17 may be an ATPase. To our knowledge, this is the first report describing the protein expression characteristics of STP17 in S. Typhi, showing that STP17 promotes bacterial growth and motility, which may be associated with its potential ATPase activity. PMID:27761429

Mitogenic effect contributes to increased virulence of Streptococcus suis sequence type 7 to cause streptococcal toxic shock-like syndrome.

PubMed

Zheng, H; Ye, C; Segura, M; Gottschalk, M; Xu, J

2008-09-01

Streptococcus suis serotype 2 sequence type 7 strains emerged in 1996 and caused a streptococcal toxic shock-like syndrome in 1998 and 2005 in China. Evidence indicated that the virulence of S. suis sequence type 7 had increased, but the mechanism was unknown. The sequence type 7 strain SC84, isolated from a patient with streptococcal toxic shock-like syndrome during the Sichuan outbreak, and the sequence type 1 strain 31533, a typical highly pathogenic strain isolated from a diseased pig, were used in comparative studies. In this study we show the mechanisms underlying cytokine production differed between the two types of strains. The S. suis sequence type 7 strain SC84 possesses a stronger capacity to stimulate T cells, naive T cells and peripheral blood mononuclear cell proliferation than does S. suis sequence type 1 strain 31533. The T cell response to both strains was dependent upon the presence of antigen-presenting cells. Histo-incompatible antigen-presenting cells were sufficient to provide the accessory signals to naive T cell stimulated by the two strains, indicating that both sequence type 7 and 1 strains possess mitogens; however, the mitogenic effect was different. Therefore, we propose that the difference in the mitogenic effect of sequence type 7 strain SC84 compared with the sequence type 1 strain 31533 of S. suis may be associated with the clinical, epidemiological and microbiological difference, where the ST 7 strains have a larger mitogenic effect.

Mitogenic effect contributes to increased virulence of Streptococcus suis sequence type 7 to cause streptococcal toxic shock-like syndrome

PubMed Central

Zheng, H; Ye, C; Segura, M; Gottschalk, M; Xu, J

2008-01-01

Streptococcus suis serotype 2 sequence type 7 strains emerged in 1996 and caused a streptococcal toxic shock-like syndrome in 1998 and 2005 in China. Evidence indicated that the virulence of S. suis sequence type 7 had increased, but the mechanism was unknown. The sequence type 7 strain SC84, isolated from a patient with streptococcal toxic shock-like syndrome during the Sichuan outbreak, and the sequence type 1 strain 31533, a typical highly pathogenic strain isolated from a diseased pig, were used in comparative studies. In this study we show the mechanisms underlying cytokine production differed between the two types of strains. The S. suis sequence type 7 strain SC84 possesses a stronger capacity to stimulate T cells, naive T cells and peripheral blood mononuclear cell proliferation than does S. suis sequence type 1 strain 31533. The T cell response to both strains was dependent upon the presence of antigen-presenting cells. Histo-incompatible antigen-presenting cells were sufficient to provide the accessory signals to naive T cell stimulated by the two strains, indicating that both sequence type 7 and 1 strains possess mitogens; however, the mitogenic effect was different. Therefore, we propose that the difference in the mitogenic effect of sequence type 7 strain SC84 compared with the sequence type 1 strain 31533 of S. suis may be associated with the clinical, epidemiological and microbiological difference, where the ST 7 strains have a larger mitogenic effect. PMID:18803762

Streptococcus mitis Strains Causing Severe Clinical Disease in Cancer Patients

PubMed Central

Sahasrabhojane, Pranoti; Saldana, Miguel; Yao, Hui; Su, Xiaoping; Horstmann, Nicola; Thompson, Erika; Flores, Anthony R.

2014-01-01

The genetically diverse viridans group streptococci (VGS) are increasingly recognized as the cause of a variety of human diseases. We used a recently developed multilocus sequence analysis scheme to define the species of 118 unique VGS strains causing bacteremia in patients with cancer; Streptococcus mitis (68 patients) and S. oralis (22 patients) were the most frequently identified strains. Compared with patients infected with non–S. mitis strains, patients infected with S. mitis strains were more likely to have moderate or severe clinical disease (e.g., VGS shock syndrome). Combined with the sequence data, whole-genome analyses showed that S. mitis strains may more precisely be considered as >2 species. Furthermore, we found that multiple S. mitis strains induced disease in neutropenic mice in a dose-dependent fashion. Our data define the prominent clinical effect of the group of organisms currently classified as S. mitis and lay the groundwork for increased understanding of this understudied pathogen. PMID:24750901

Comparative genomic and proteomic analyses of Clostridium acetobutylicum Rh8 and its parent strain DSM 1731 revealed new understandings on butanol tolerance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bao, Guanhui; University of Chinese Academy of Sciences, Beijing; Dong, Hongjun

Highlights: • Genomes of a butanol tolerant strain and its parent strain were deciphered. • Comparative genomic and proteomic was applied to understand butanol tolerance. • None differentially expressed proteins have mutations in its corresponding genes. • Mutations in ribosome might be responsible for the global difference of proteomics. - Abstract: Clostridium acetobutylicum strain Rh8 is a butanol-tolerant mutant which can tolerate up to 19 g/L butanol, 46% higher than that of its parent strain DSM 1731. We previously performed comparative cytoplasm- and membrane-proteomic analyses to understand the mechanism underlying the improved butanol tolerance of strain Rh8. In this work,more » we further extended this comparison to the genomic level. Compared with the genome of the parent strain DSM 1731, two insertion sites, four deletion sites, and 67 single nucleotide variations (SNVs) are distributed throughout the genome of strain Rh8. Among the 67 SNVs, 16 SNVs are located in the predicted promoters and intergenic regions; while 29 SNVs are located in the coding sequence, affecting a total of 21 proteins involved in transport, cell structure, DNA replication, and protein translation. The remaining 22 SNVs are located in the ribosomal genes, affecting a total of 12 rRNA genes in different operons. Analysis of previous comparative proteomic data indicated that none of the differentially expressed proteins have mutations in its corresponding genes. Rchange Algorithms analysis indicated that the mutations occurred in the ribosomal genes might change the ribosome RNA thermodynamic characteristics, thus affect the translation strength of these proteins. Take together, the improved butanol tolerance of C. acetobutylicum strain Rh8 might be acquired through regulating the translational process to achieve different expression strength of genes involved in butanol tolerance.« less

Rheology of arc dacite lavas: experimental determination at low strain rates

NASA Astrophysics Data System (ADS)

Avard, Geoffroy; Whittington, Alan G.

2012-07-01

Andesitic-dacitic volcanoes exhibit a large variety of eruption styles, including explosive eruptions, endogenous and exogenous dome growth, and kilometer-long lava flows. The rheology of these lavas can be investigated through field observations of flow and dome morphology, but this approach integrates the properties of lava over a wide range of temperatures. Another approach is through laboratory experiments; however, previous studies have used higher shear stresses and strain rates than are appropriate to lava flows. We measured the apparent viscosity of several lavas from Santiaguito and Bezymianny volcanoes by uniaxial compression, between 1,109 and 1,315 K, at low shear stress (0.085 to 0.42 MPa), low strain rate (between 1.1 × 10-8 and 1.9 × 10-5 s-1), and up to 43.7 % total deformation. The results show a strong variability of the apparent viscosity between different samples, which can be ascribed to differences in initial porosity and crystallinity. Deformation occurs primarily by compaction, with some cracking and/or vesicle coalescence. Our experiments yield apparent viscosities more than 1 order of magnitude lower than predicted by models based on experiments at higher strain rates. At lava flow conditions, no evidence of a yield strength is observed, and the apparent viscosity is best approached by a strain rate- and temperature-dependent power law equation. The best fit for Santiaguito lava, for temperatures between 1,164 and 1,226 K and strain rates lower than 1.8 × 10-4 s-1, is log {η_{{app}}} = - 0.738 + 9.24 × {10^3}{/}T(K) - 0.654 \\cdot log dot{\\varepsilon } where η app is apparent viscosity and dot{\\varepsilon } is strain rate. This equation also reproduced 45 data for a sample from Bezymianny with a root mean square deviation of 0.19 log unit Pa s. Applying the rheological model to lava flow conditions at Santiaguito yields calculated apparent viscosities that are in reasonable agreement with field observations and suggests that internal shear heating may be significant ongoing heat source within these flows, enabling highly viscous lava to travel long distances.

Reengineering of the feedback-inhibition enzyme N-acetyl-L-glutamate kinase to enhance L-arginine production in Corynebacterium crenatum.

PubMed

Zhang, Jingjing; Xu, Meijuan; Ge, Xiaoxun; Zhang, Xian; Yang, Taowei; Xu, Zhenghong; Rao, Zhiming

2017-02-01

N-acetyl-L-glutamate kinase (NAGK) catalyzes the second step of L-arginine biosynthesis and is inhibited by L-arginine in Corynebacterium crenatum. To ascertain the basis for the arginine sensitivity of CcNAGK, residue E19 which located at the entrance of the Arginine-ring was subjected to site-saturated mutagenesis and we successfully illustrated the inhibition-resistant mechanism. Typically, the E19Y mutant displayed the greatest deregulation of L-arginine feedback inhibition. An equally important strategy is to improve the catalytic activity and thermostability of CcNAGK. For further strain improvement, we used site-directed mutagenesis to identify mutations that improve CcNAGK. Results identified variants I74V, F91H and K234T display higher specific activity and thermostability. The L-arginine yield and productivity of the recombinant strain C. crenatum SYPA-EH3 (which possesses a combination of all four mutant sites, E19Y/I74V/F91H/K234T) reached 61.2 and 0.638 g/L/h, respectively, after 96 h in 5 L bioreactor fermentation, an increase of approximately 41.8% compared with the initial strain.

Systems perspectives on erythromycin biosynthesis by comparative genomic and transcriptomic analyses of S. erythraea E3 and NRRL23338 strains

PubMed Central

2013-01-01

Background S. erythraea is a Gram-positive filamentous bacterium used for the industrial-scale production of erythromycin A which is of high clinical importance. In this work, we sequenced the whole genome of a high-producing strain (E3) obtained by random mutagenesis and screening from the wild-type strain NRRL23338, and examined time-series expression profiles of both E3 and NRRL23338. Based on the genomic data and transcriptpmic data of these two strains, we carried out comparative analysis of high-producing strain and wild-type strain at both the genomic level and the transcriptomic level. Results We observed a large number of genetic variants including 60 insertions, 46 deletions and 584 single nucleotide variations (SNV) in E3 in comparison with NRRL23338, and the analysis of time series transcriptomic data indicated that the genes involved in erythromycin biosynthesis and feeder pathways were significantly up-regulated during the 60 hours time-course. According to our data, BldD, a previously identified ery cluster regulator, did not show any positive correlations with the expression of ery cluster, suggesting the existence of alternative regulation mechanisms of erythromycin synthesis in S. erythraea. Several potential regulators were then proposed by integration analysis of genomic and transcriptomic data. Conclusion This is a demonstration of the functional comparative genomics between an industrial S. erythraea strain and the wild-type strain. These findings help to understand the global regulation mechanisms of erythromycin biosynthesis in S. erythraea, providing useful clues for genetic and metabolic engineering in the future. PMID:23902230

Phenotypic characterisation of Saccharomyces spp. for tolerance to 1-butanol.

PubMed

Zaki, A M; Wimalasena, T T; Greetham, D

2014-11-01

Biofuels are expected to play a role in replacing crude oil as a liquid transportation fuel, and research into butanol has highlighted the importance of this alcohol as a fuel. Butanol has a higher energy density than ethanol, butanol-gasoline blends do not separate in the presence of water, and butanol is miscible with gasoline (Szulczyk, Int J Energy Environ 1(1):2876-2895, 40). Saccharomyces cerevisiae has been used as a fermentative organism in the biofuel industry producing ethanol from glucose derived from starchy plant material; however, it typically cannot tolerate butanol concentrations greater than 2 % (Luong, Biotechnol Bioeng 29 (2):242-248, 27). 90 Saccharomyces spp. strains were screened for tolerance to 1-butanol via a phenotypic microarray assay and we observed significant variation in response with the most tolerant strains (S. cerevisiae DBVPG1788, S. cerevisiae DBVPG6044 and S. cerevisiae YPS128) exhibiting tolerance to 4 % 1-butanol compared with S. uvarum and S. castelli strains, which were sensitive to 3 % 1-butanol. Response to butanol was confirmed using traditional yeast methodologies such as growth; it was observed that fermentations in the presence of butanol, when using strains with a tolerant background, were significantly faster. Assessing for genetic rationale for tolerance, it was observed that 1-butanol-tolerant strains, when compared with 1-butanol-sensitive strains, had an up-regulation of RPN4, a transcription factor which regulates proteasome genes. Analysing for the importance of RPN4, we observed that a Δrpn4 strain displayed a reduced rate of fermentation in the presence of 1-butanol when compared with the BY4741 background strain. This data will aid the development of breeding programmes to produce better strains for future bio-butanol production.

Comparative genomics among Saccharomyces cerevisiae × Saccharomyces kudriavzevii natural hybrid strains isolated from wine and beer reveals different origins

PubMed Central

2012-01-01

Background Interspecific hybrids between S. cerevisiae × S. kudriavzevii have frequently been detected in wine and beer fermentations. Significant physiological differences among parental and hybrid strains under different stress conditions have been evidenced. In this study, we used comparative genome hybridization analysis to evaluate the genome composition of different S. cerevisiae × S. kudriavzevii natural hybrids isolated from wine and beer fermentations to infer their evolutionary origins and to figure out the potential role of common S. kudriavzevii gene fraction present in these hybrids. Results Comparative genomic hybridization (CGH) and ploidy analyses carried out in this study confirmed the presence of individual and differential chromosomal composition patterns for most S. cerevisiae × S. kudriavzevii hybrids from beer and wine. All hybrids share a common set of depleted S. cerevisiae genes, which also are depleted or absent in the wine strains studied so far, and the presence a common set of S. kudriavzevii genes, which may be associated with their capability to grow at low temperatures. Finally, a maximum parsimony analysis of chromosomal rearrangement events, occurred in the hybrid genomes, indicated the presence of two main groups of wine hybrids and different divergent lineages of brewing strains. Conclusion Our data suggest that wine and beer S. cerevisiae × S. kudriavzevii hybrids have been originated by different rare-mating events involving a diploid wine S. cerevisiae and a haploid or diploid European S. kudriavzevii strains. Hybrids maintain several S. kudriavzevii genes involved in cold adaptation as well as those related to S. kudriavzevii mitochondrial functions. PMID:22906207

Effect of Egg Washing and Correlation between Eggshell Characteristics and Egg Penetration by Various Salmonella Typhimurium Strains

PubMed Central

Gole, Vaibhav C.; Chousalkar, Kapil K.; Roberts, Juliet R.; Sexton, Margaret; May, Damian; Tan, Jessica; Kiermeier, Andreas

2014-01-01

Salmonella is an important foodborne pathogen, causing an estimated 11,992 cases of infection in Australia per year. Egg or egg product related salmonellosis is a major concern for the egg industry. Worldwide, S. Typhimurium is one of the most common serovars identified in Salmonella food poisoning cases. The current study investigated the ability of five S. Typhimurium strains to penetrate washed and unwashed eggs using whole egg and agar egg penetration methods. All S. Typhimurium strains were able to penetrate eggshells and survive in egg albumen (at 20°C) according to whole egg penetration results. Polymerase Chain Reaction results demonstrated that S. Typhimurium strain 2 (103 and 105 CFU/mL), and strain 5 (103 and 105 CFU/mL) egg penetration was significantly higher (p<0.05) in washed eggs when compared to unwashed eggs. Statistical analysis of the agar penetration experiment indicated that S. Typhimurium was able to penetrate washed eggs at a significantly higher rate when compared to unwashed eggs (p<0.05). When compared to unwashed eggs, washed eggs also had significantly damaged cuticles. Statistical analysis also indicated that eggshell penetration by S. Typhimurium was related to various eggshell ultrastructural features such as cap quality, alignment, erosion, confluence, Type B bodies and cuticle cover. PMID:24621821

Transcriptional analysis of four family 4 P450s in a Puerto Rico strain of Aedes aegypti (Diptera: Culicidae) compared with an Orlando strain and their possible functional roles in permethrin resistance

USDA-ARS?s Scientific Manuscript database

A field strain of Aedes aegypti was collected from Puerto Rico (PR) in October 2008. Based on LD50 values by topical application, the PR strain was 73-fold resistant to permethrin compared to a susceptible Orlando strain. In the presence of piperonyl butoxide (PBO), the resistance of Puerto Rico str...

Co-producing iturin A and poly-γ-glutamic acid from rapeseed meal under solid state fermentation by the newly isolated Bacillus subtilis strain 3-10.

PubMed

Yao, Dehui; Ji, Zhixia; Wang, Changjun; Qi, Gaofu; Zhang, Lili; Ma, Xin; Chen, Shouwen

2012-03-01

The strain 3-10 was isolated from soil and identified as B. subtilis according to morphological and physiological characteristics and nucleotide sequence of 16S rRNA. It co-produced anti-fungal iturin A and fertilizer synergist of poly-γ-glutamic acid (γ-PGA) under solid state fermentation (SSF) with rapeseed meal. The co-production of iturin A and γ-PGA reached 5.3 and 51.3 g/kg-dry weight culture, respectively, and the number of viable cells reached 1.9 × 10(10) CFU/g-dry weight culture. In pot tests, the shoot length and dry weight of watermelon seedlings treated by the SSF culture improved by 48.0 and 30.8%, respectively compared to the control; and its biocontrol effect on watermelon fusarium wilt achieved 89.6%. These results highlight a novel strategy to exploit the low-cost and widely available rapeseed meal as dual-functional bio-organic fertilizer under SSF by B. subtilis.

40-Hz square-wave stimulation requires less energy to produce muscle contraction: compared with the TASER® X26 conducted energy weapon.

PubMed

Comeaux, James A; Jauchem, James R; Cox, D Duane; Crane, Carrie C; D'Andrea, John A

2013-07-01

Conducted energy weapons (CEWs) (including the Advanced TASER(®) X26 model produced by TASER International, Inc.) incapacitate individuals by causing muscle contractions. In this study using anesthetized swine, the potential incapacitating effect of primarily monophasic, 19-Hz voltage imposed by the commercial CEW was compared with the effect of voltages imposed by a laboratory device that created 40-Hz square waves. Forces of muscle contraction were measured with the use of strain gauges. Stimulation with 40-Hz square waves required less pulse energy than stimulation with the commercial CEW to produce similar muscle contraction. The square-pulse stimulation, at the higher repetition rate, caused a more complete tetanus at a lower energy. Use of such a simple shape of waveform may be used to make future nonlethal weapon devices more efficient. © 2013 American Academy of Forensic Sciences Published 2013. This article is a U.S. Government work and is in the public domain in the U.S.A.

Digital data for quick response (QR) codes of alkalophilic Bacillus pumilus to identify and to compare bacilli isolated from Lonar Crator Lake, India

PubMed Central

Rekadwad, Bhagwan N.; Khobragade, Chandrahasya N.

2016-01-01

Microbiologists are routinely engaged isolation, identification and comparison of isolated bacteria for their novelty. 16S rRNA sequences of Bacillus pumilus were retrieved from NCBI repository and generated QR codes for sequences (FASTA format and full Gene Bank information). 16SrRNA were used to generate quick response (QR) codes of Bacillus pumilus isolated from Lonar Crator Lake (19° 58′ N; 76° 31′ E), India. Bacillus pumilus 16S rRNA gene sequences were used to generate CGR, FCGR and PCA. These can be used for visual comparison and evaluation respectively. The hyperlinked QR codes, CGR, FCGR and PCA of all the isolates are made available to the users on a portal https://sites.google.com/site/bhagwanrekadwad/. This generated digital data helps to evaluate and compare any Bacillus pumilus strain, minimizes laboratory efforts and avoid misinterpretation of the species. PMID:27141529

[Isolation and identification of Cronobacter (Enterobacter sakazakii) strains from food].

PubMed

Dong, Xiaohui; Li, Chengsi; Wu, Qingping; Zhang, Jumei; Mo, Shuping; Guo, Weipeng; Yang, Xiaojuan; Xu, Xiaoke

2013-05-04

This study aimed to detect and quantify Cronobacter in 300 powdered milk samples and 50 non-powdered milk samples. Totally, 24 Cronobacter (formerly Enterobacter sakazakii) strains isolated from powdered milk and other foods were identified and confirmed. Cronobacter strains were detected quantitatively using most probable number (MPN) method and molecular detection method. We identified 24 Cronobacter strains using biochemical patterns, including indole production and dulcitol, malonate, melezitose, turanose, and myo-Inositol utilization. Of the 24 strains, their 16S rRNA genes were sequenced, and constructed phylogenetic tree by N-J (Neighbour-Joining) with the 16S rRNA gene sequences of 17 identified Cronobacter strains and 10 non-Cronobacter strains. Quantitative detection showed that Cronobacter strains were detected in 23 out of 350 samples yielding 6.6% detection rate. Twenty-four Cronobacter strains were isolated from 23 samples and the Cronobacter was more than 100 MPN/100g in 4 samples out of 23 samples. The 24 Cronobacter spp. isolates strains were identified and confirmed, including 19 Cronobacter sakazakii strains, 2 C. malonaticus strains, 2 C. dubliensis subsp. lactaridi strains, and 1 C. muytjensii strain. The combination of molecular detection method and most probable number (MPN) method could be suitable for the detection of Cronobacter in powdered milk, with low rate of contamination and high demand of quantitative detection. 24 isolated strains were confirmed and identified by biochemical patterns and molecular technology, and C. sakazakii could be the dominant species. The problem of Cronobacter in powdered milk should be a hidden danger to nurseling, and should catch the government and consumer's attention.

Effect of the luxS gene on biofilm formation and antibiotic resistance by Salmonella serovar Dublin.

PubMed

Ju, Xiangyu; Li, Junjie; Zhu, Mengjiao; Lu, Zhaoxin; Lv, Fengxia; Zhu, Xiaoyu; Bie, Xiaomei

2018-05-01

Biofilms are communities of bacterial cells that serve to protect them from external adverse influences and enhance bacterial resistance to antibiotics and sanitizers. Here, we studied the regulatory effects of glucose and sodium chloride on biofilm formation in Salmonella serovar Dublin (S. Dublin). To analyze expression levels of the quorum sensing gene luxS, we created a luxS knockout mutant. Also, antimicrobial resistance, hydrophobicity and autoinducer-2 (AI-2) activity of both the wild-type (WT) and the mutant strain were investigated. Our results revealed that glucose was not essential for S. Dublin biofilm formation but had an inhibitory effect on biofilm formation when the concentration was over 0.1%. NaCl was found to be indispensable in forming biofilm, and it also exerted an inhibitory effect at high concentrations (>1.0%). Both the WT and the mutant strains displayed significant MIC growth after biofilm formation. An increase of up to 32,768 times in the resistance of S. Dublin in biofilm phonotype against antibiotic (ampicillin) compared to its planktonic phonotype was observed. However, S. Dublin luxS knockout mutant only showed slight differences compared to the WT strain in the antimicrobial tests although it displayed better biofilm-forming capacity than the WT strain. The mutant strain also exhibited higher hydrophobicity than the WT strain, which was a feature related to biofilm formation. The production of the quorum sensing autoinducer-2 (AI-2) was significantly lower in the mutant strain than in the WT strain since the LuxS enzyme, encoded by the luxS gene, plays an essential role in AI-2 synthesis. However, the limited biofilm-forming ability in the WT strain indicated AI-2 was not directly related to S. Dublin biofilm formation. Furthermore, gene expression analysis of the WT and mutant strains revealed upregulation of genes related to biofilm stress response and enhanced resistance in the luxS mutant strain, which may provide evidence for the regulatory role of the luxS gene in biofilm formation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Studies of Giardia lamblia

DTIC Science & Technology

1994-10-05

isoenzyme analysis of 19 axenic strains isolated from symptomatic and asymptomatic patients in Mexico . Trans. R. Soc. Trop. Med. Hyg. 83 : 644-646...antibody studies with agents of Varicella and Herpes Zoster propagated in vitro. Proe. Soc. Exptl. BioI. Med . 86 :7 89-794. Woo, P. and G.S. Panayi

Antistaphylococcal Activity of DX-619, a New Des-F(6)-Quinolone, Compared to Those of Other Agents

PubMed Central

Bogdanovich, Tatiana; Esel, Duygu; Kelly, Linda M.; Bozdogan, Bülent; Credito, Kim; Lin, Gengrong; Smith, Kathy; Ednie, Lois M.; Hoellman, Dianne B.; Appelbaum, Peter C.

2005-01-01

The in vitro activity of DX-619, a new des-F(6)-quinolone, was tested against staphylococci and compared to those of other antimicrobials. DX-619 had the lowest MIC ranges/MIC50s/MIC90s (μg/ml) against 131 Staphylococcus aureus strains (≤0.002 to 2.0/0.06/0.5) and 128 coagulase-negative staphylococci (0.004 to 0.25/0.016/0.125). Among strains tested, 76 S. aureus strains and 51 coagulase-negative staphylococci were resistant to ciprofloxacin. DX-619 had the lowest MIC50/MIC90 values against 127 quinolone-resistant staphylococci (0.125/0.5), followed by sitafloxacin (0.5/4), moxifloxacin (2/8), gatifloxacin (4/16), levofloxacin (16/>32), and ciprofloxacin (>32/>32). Raised quinolone MICs were associated with mutations in GyrA (S84L) and single or double mutations in GrlA (S80F or Y; E84K, G, or V) in all S. aureus strains tested. A recent vancomycin-resistant S. aureus (VRSA) strain (Hershey) was resistant to available quinolones and was inhibited by DX-619 at 0.25 μg/ml and sitafloxacin at 1.0 μg/ml. Vancomycin (except VRSA), linezolid, ranbezolid, tigecycline, and quinupristin-dalfopristin were active against all strains, and teicoplanin was active against S. aureus but less active against coagulase-negative staphylococci. DX-619 produced resistant mutants with MICs of 1 to >32 μg/ml after <50 days of selection compared to 16 to >32 μg/ml for ciprofloxacin, sitafloxacin, moxifloxacin, and gatifloxacin. DX-619 and sitafloxacin were also more active than other tested drugs against selected mutants and had the lowest mutation frequencies in single-step resistance selection. DX-619 and sitafloxacin were bactericidal against six quinolone-resistant (including the VRSA) and seven quinolone-susceptible strains tested, whereas gatifloxacin, moxifloxacin, levofloxacin, and ciprofloxacin were bactericidal against 11, 10, 7, and 5 strains at 4× MIC after 24 h, respectively. DX-619 was also bactericidal against one other VRSA strain, five vancomycin-intermediate S. aureus strains, and four vancomycin-intermediate coagulase-negative staphylococci. Linezolid, ranbezolid, and tigecycline were bacteriostatic and quinupristin-dalfopristin, teicoplanin, and vancomycin were bactericidal against two, eight, and nine strains, and daptomycin and oritavancin were rapidly bactericidal against all strains, including the VRSA. DX-619 has potent in vitro activity against staphylococci, including methicillin-, ciprofloxacin-, and vancomycin-resistant strains. PMID:16048943

Probiotic lactobacilli interfere with Streptococcus mutans biofilm formation in vitro.

PubMed

Söderling, Eva M; Marttinen, Aino M; Haukioja, Anna L

2011-02-01

In clinical studies, probiotic bacteria have decreased the counts of salivary mutans streptococci (MS). We compared the effects of probiotic Lactobacillus strains on the biofilm formation of Streptococcus mutans. The bacterial strains used included four S. mutans strains (reference strains NCTC 10449 and Ingbritt and clinical isolates 2366 and 195) and probiotic strains Lactobacillus rhamnosus GG, L. plantarum 299v, and L. reuteri strains PTA 5289 and SD2112. The ability of MS to adhere and grow on a glass surface, reflecting biofilm formation, was studied in the presence of the lactobacilli (LB). The effect of LB culture supernatants on the viability of the MS was studied as well. All of the LB inhibited the biofilm formation of the clinical isolates of MS (P < 0.001). The biofilm formation of the reference strains of MS was also inhibited by the LB, but L. plantarum and L. reuteri PTA 5289 showed a weaker inhibition when compared to L. reuteri SD2112 and L. rhamnosus GG. Viable S. mutans cells could be detected in the biofilms and culture media only when the experiments were performed with the L. reuteri strains. The L. reuteri strains were less efficient in killing the MS also in the tests performed with the culture supernatants. The pHs of the supernatants of L. reuteri were higher compared to those of L. rhamnosus GG and L. plantarum; P < 0.001. In conclusion, our results demonstrated that four commonly used probiotics interfered with S. mutans biofilm formation in vitro, and that the antimicrobial activity against S. mutans was pH-dependent.

Effect of texture on rheological properties: the case of ɛ-Fe (Invited)

NASA Astrophysics Data System (ADS)

Merkel, S.; Gruson, M.; Tomé, C. N.; Nishiyama, N.; Wang, Y.

2009-12-01

Lattice preferred orientations (LPO) are known to affect the physical properties of materials. However, in most high pressure deformation experiments, LPO are ignored when interpreting the measured stress-strain curves. In addition, stress measurements in those experiments are complicated by the effect of plastic deformation on the measured lattice strains(1). Here, we present a new interpretation of the results obtained on hcp-iron at up to 19 GPa and 600 K in the deformation-DIA(2). In those experiments, five independent stress-strain curves were obtained on axial shortening with a ductile behavior of the sample for all. Stress were studied using results of monochromatic X-ray diffraction and the elastic theory of lattice strains(3). However, measured stresses were inconsistent with a change of behavior after 4% axial strain, particularly for strains measured on the 0002 line. We use elasto-plastic self consistent modeling(1) to show that this change of behavior is due to the evolution of LPO in the sample. With compression, 10-10 planes in hcp-iron align parallel to the compression direction and this affects the rheological behavior of the sample, which can not be summarized in a simple average law. We will also discuss the implication of those results for the extraction of polycrystalline rheological properties for materials with non-random lattice preferred orientations and how this could affect our understanding of the Earth deep interior. 1- S. Merkel, C.N. Tomé, H.-R Wenk, A modeling analysis of the influence of plasticity on high pressure deformation of hcp-Co, Phys. Rev. B, 79, 064110 (2009) 2- N. Nishiyama, Y. Wang, M. L. Rivers, S. R. Sutton, D. Cookson, Rheology of e-iron up to 19 GPa and 600 K in the D-DIA, Geophys. Res. Lett., 34, L23304 (2007) 3- A. K. Singh, C. Balasingh, H. K. Mao, R. J. Hemley, J. Shu, Analysis of lattice strains measured under non-hydrostatic pressure, J. Appl. Phys., 83, 7567-7575 (1998)

Agaricicola taiwanensis gen. nov., sp. nov., an alphaproteobacterium isolated from the edible mushroom Agaricus blazei.

PubMed

Chu, Jiunn-Nan; Arun, A B; Chen, Wen-Ming; Chou, Jui-Hsing; Shen, Fo-Ting; Rekha, P D; Kämpfer, P; Young, Li-Sen; Lin, Shih-Yao; Young, Chiu-Chung

2010-09-01

A Gram-negative, beige-pigmented, aerobic, motile, club-shaped bacterium, designated strain CC-SBABM117(T), was isolated from the stipe of the edible mushroom Agaricus blazei Murrill. 16S rRNA gene sequence analysis demonstrated that the strain shared <93 % similarity with the type strains of species in the genera Pannonibacter, Methylopila, Nesiotobacter and Stappia. The organism was unable to produce acid from carbohydrates, but utilized a number of organic acids and amino acids. Ubiquinone 10 (Q-10) was the major respiratory quinone and C(18 : 1) ω 7c, C(19 : 0) cyclo ω 8c, C(16 : 0) and C(18 : 0) were the predominant fatty acids. The predominant polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol and phosphatidylethanolamine. The DNA G+C content of strain CC-SBABM117(T) was 62.7 mol%. On the basis of 16S rRNA gene sequence analysis and chemotaxonomic and physiological data, strain CC-SBABM117(T) is considered to represent a novel species of a new genus, for which the name Agaricicola taiwanensis gen. nov., sp. nov. is proposed. The type strain of Agaricicola taiwanensis is CC-SBABM117(T) (=BCRC 17964(T) =CCM 7684(T)).

Distinct Biological Potential of Streptococcus gordonii and Streptococcus sanguinis Revealed by Comparative Genome Analysis.

PubMed

Zheng, Wenning; Tan, Mui Fern; Old, Lesley A; Paterson, Ian C; Jakubovics, Nicholas S; Choo, Siew Woh

2017-06-07

Streptococcus gordonii and Streptococcus sanguinis are pioneer colonizers of dental plaque and important agents of bacterial infective endocarditis (IE). To gain a greater understanding of these two closely related species, we performed comparative analyses on 14 new S. gordonii and 5 S. sanguinis strains using various bioinformatics approaches. We revealed S. gordonii and S. sanguinis harbor open pan-genomes and share generally high sequence homology and number of core genes including virulence genes. However, we observed subtle differences in genomic islands and prophages between the species. Comparative pathogenomics analysis identified S. sanguinis strains have genes encoding IgA proteases, mitogenic factor deoxyribonucleases, nickel/cobalt uptake and cobalamin biosynthesis. On the contrary, genomic islands of S. gordonii strains contain additional copies of comCDE quorum-sensing system components involved in genetic competence. Two distinct polysaccharide locus architectures were identified, one of which was exclusively present in S. gordonii strains. The first evidence of genes encoding the CylA and CylB system by the α-haemolytic S. gordonii is presented. This study provides new insights into the genetic distinctions between S. gordonii and S. sanguinis, which yields understanding of tooth surfaces colonization and contributions to dental plaque formation, as well as their potential roles in the pathogenesis of IE.

Complete genome sequence of an attenuated Sparfloxacin resistant Streptococcus agalactiae strain 138spar

USDA-ARS?s Scientific Manuscript database

Through selection of resistance to sparfloxacin, an attenuated Streptococcus agalactiae strain 138spar was obtained from its virulent parent strain S. agalactiae 138P. The full genome of S. agalactiae 138spar is 1,838,126 bp. The availability of this genome will allow comparative genomics to identi...

Lactoferrin-binding proteins in Shigella flexneri.

PubMed Central

Tigyi, Z; Kishore, A R; Maeland, J A; Forsgren, A; Naidu, A S

1992-01-01

The ability of Shigella flexneri to interact with lactoferrin (Lf) was examined with a 125I-labeled protein-binding assay. The percent binding of human lactoferrin (HLf) and bovine lactoferrin (BLf) to 45 S. flexneri strains was 19 +/- 3 and 21 +/- 3 (mean +/- standard error of the mean), respectively. 125I-labeled HLf and BLf binding to strain M90T reached an equilibrium within 2 h. Unlabeled HLf and BLf displaced the 125I-HLf-bacteria interaction in a dose-dependent manner. The Lf-bacterium complex was uncoupled by KSCN or urea, but not by NaCl. The interaction was specific, and approximately 4,800 HLf binding sites (affinity constant [Ka], 690 nM) or approximately 5,700 BLf binding sites (Ka, 104 nM) per cell were estimated in strain M90T by a Scatchard plot analysis. The native cell envelope (CE) and outer membrane (OM) did not reveal Lf-binding components in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. However, after being boiled, the CE and OM preparations showed three distinct horseradish peroxidase-Lf reactive bands of about 39, 22, and 16 kDa. The 39-kDa component was also reactive to a monoclonal antibody specific for porin (PoI) proteins of members of the family Enterobacteriaceae. The Lf-binding protein pattern was similar with BLf or HLf, for Crb+ and Crb- strains. The protein-Lf complex was dissociable by KSCN or urea and was stable after treatment with NaCl. Variation (loss) in the O chain of lipopolysaccharide (LPS) markedly enhanced the Lf-binding capacity in the isogenic rough strain SFL1070-15 compared with its smooth parent strain, SFL1070. These data establish that Lf binds to specific components in the bacterial OM; the heat-modifiable, anti-PoI-reactive, and LPS-associated properties suggested that the Lf-binding proteins are porins in S. flexneri. Images PMID:1319403

[Development of long-term post-tetanic potentiation and changes in S-100 protein contents in hippocampal slices of rats in different functional states].

PubMed

Baĭdo, A I; Shiriaeva, N V; Khichenko, V I; Liuboslavskaia, P N; Starostina, M V

1992-06-01

Male rats of the strains with low (LE) high excitability (HE) of the nervous system have been used in this study. Half of the animals of each strain were neurotized in accordance with the Hecht's scheme. In the hippocampal slices of the non-neurotized LE rats there was a significant increase of the populational spike amplitude during development of LTP as compared with the opposite group of the animals. The LTP formation in the LE strain of rats caused a decrease in the S-100 protein content in the water-soluble, and an increase in the membrane-bound fraction of the protein. Similar results we have observed with the non-inbred Wistar rats but not with the HE strain of the animals. The levels of the water-soluble S-100 protein fraction were also higher in the hippocampuses and entorenal cortices, but not in the cerebellae of the LE strain, as compared with the HE strain of the rats. No differences have been found in the membrane-bound fraction of S-100 protein.

Three-dimensional speckle tracking echocardiography allows detailed evaluation of left atrial function in hypertrophic cardiomyopathy--insights from the MAGYAR-Path Study.

PubMed

Domsik, Péter; Kalapos, Anita; Chadaide, Számi; Sepp, Róbert; Hausinger, Péter; Forster, Tamás; Nemes, Attila

2014-11-01

Hypertrophic cardiomyopathy (HCM) represents a generalized myopathic process affecting both ventricular and atrial myocardium. Reduced left atrial (LA) function was demonstrated in HCM by different methods. Three-dimensional (3D) speckle tracking echocardiography (STE) has just been introduced for the evaluation of LA. This study was designed to compare 3DSTE-derived LA volumetric and strain parameters in HCM with healthy controls. The study comprised 23 consecutive HCM patients (mean age: 48.5 ± 15.1 years, 14 men). Their results were compared to 23 age- and gender-matched healthy controls. Complete two-dimensional Doppler echocardiography and 3DSTE have been performed in all cases. Calculated LA maximum (66.4 ± 20.4 mL vs. 36.0 ± 6.1 mL, P < 0.0001) and minimum (39.2 ± 19.1 vs. 16.0 ± 4.6 mL, P < 0.0001) volumes and LA volume before atrial contraction (53.6 ± 19.9 vs. 24.0 ± 6.2 mL, P < 0.0001) were significantly increased in HCM patients. Atrial stroke volumes respecting cardiac cycles proved to be increased, while emptying fractions were decreased in subjects with HCM. Mean global radial (-12.2 ± 6.7% vs. -19.6 ± 11.7, P < 0.05), longitudinal (26.5 ± 16.5% vs. 29.8 ± 12.1%, P < 0.05) and 3D strain (-6.1 ± 4.4% vs. -12.5 ± 10.2%, P < 0.05) proved to be significantly reduced in HCM patients as compared with matched controls. Three-dimensional speckle tracking echocardiography allows detailed evaluation of LA (dys) function in HCM by volumetric and strain measurements. © 2014, Wiley Periodicals, Inc.

Bovine origin Staphylococcus aureus: A new zoonotic agent?

PubMed Central

Rao, Relangi Tulasi; Jayakumar, Kannan; Kumar, Pavitra

2017-01-01

Aim: The study aimed to assess the nature of animal origin Staphylococcus aureus strains. The study has zoonotic importance and aimed to compare virulence between two different hosts, i.e., bovine and ovine origin. Materials and Methods: Conventional polymerase chain reaction-based methods used for the characterization of S. aureus strains and chick embryo model employed for the assessment of virulence capacity of strains. All statistical tests carried on R program, version 3.0.4. Results: After initial screening and molecular characterization of the prevalence of S. aureus found to be 42.62% in bovine origin samples and 28.35% among ovine origin samples. Meanwhile, the methicillin-resistant S. aureus prevalence is found to be meager in both the hosts. Among the samples, only 6.8% isolates tested positive for methicillin resistance. The biofilm formation quantified and the variation compared among the host. A Welch two-sample t-test found to be statistically significant, t=2.3179, df=28.103, and p=0.02795. Chicken embryo model found effective to test the pathogenicity of the strains. Conclusion: The study helped to conclude healthy bovines can act as S. aureus reservoirs. Bovine origin S. aureus strains are more virulent than ovine origin strains. Bovine origin strains have high probability to become zoonotic pathogen. Further, gene knock out studies may be conducted to conclude zoonocity of the bovine origin strains. PMID:29184376

The hydrolytic enzymes produced by fungi strains isolated from the sand and soil of recreational areas

PubMed

Kurnatowski, Piotr; Wójcik, Anna; Błaszkowska, Joanna; Góralska, Katarzyna

2016-10-01

The pathogenicity of fungi depends on, inter alia, the secretion of hydrolytic enzymes. The aim of this study was to determine the enzymatic activity of yeasts and yeast-like fungi isolated from children’s recreation areas, and compare the results with literature data of strains obtained from patients with mycoses. The enzymatic activity of 96 strains was assessed using an API ZYM kit (bioMerieux, France) and their biotypes were established. The fungal species were found to produce from 16 to 19 hydrolases: the most active were: leucine arylamidase (e5), acid phosphatase (e10), alkaline phosphatase (e1), naphthol-AS-BI-phosphohydrolase (e11), esterase – C4 (e2), β-galac - tosidase (e13) and β-glucosidase (e16). In addition, 13 biotypes characteristic of particular species of fungi were defined. Most strains could be categorized as biotypes C2 – 39.5% and A – 26%. The examined fungal strains isolated from recreational areas have selected biochemical characteristics i.e. production of hydrolases, which demonstrate their pathogenicity. They produce a number of enzymes which are also present in strains isolated from patients with mycoses, including: leucine arylamidase (e5), acid phosphatase (e10), naphthol-AS-BI-phosphohydrolase (e11) and alkaline phosphatase (e1). The biotypes identified in the course of this study (A, B3, B4, C1, C6 and D3) have been also reported in cases of fungal infection. Therefore, the fungi present in the sand and soil of recreational have pathogenic properties and are possible factors of fungal infection among children.

Streptomyces fuscichromogenes sp. nov., an actinomycete from soil.

PubMed

Zhang, Hao; Zheng, Jimei; Zhuang, Junli; Xin, Yuhua; Zheng, Xiaowei; Zhang, Jianli

2017-01-01

A novel actinomycete, designated strain m16T, was isolated from a soil sample collected from the tropical rain forest of Xishuangbanna, a prefecture in Yunnan Province, south-west China, and characterized by using polyphasic taxomomy. Cells were aerobic and Gram-reaction-positive, and spore chains were observed to be of the helical type, with elliptical spores and smooth spore surfaces. The novel strain grew over a temperature range of 15-35 °C, at pH 5.0-11.0 and in the presence of 0-3 % (w/v) NaCl. The DNA G+C content of strain m16T was 70.0 mol%. The main fatty acids were iso-C16 : 0 (29.3 %), iso-C15: 0 (15.4 %) and anteiso-C15:0 (14.6 %), and the predominant menaquinones were MK-9(H6), MK-9(H8) and MK-9(H4). Comparative 16S rRNA gene sequence analysis showed that strain m16T was most closely related to Streptomyces jiujiangensis KCTC 29262T (98.7 %), Streptomyces panaciradicis KACC 17632T (98.7 %), Streptomyces rhizophilus NBRC 108885T (98.5 %), Streptomyces shenzhenensis DSM 42034T (98.4 %), Streptomyces graminisoli JR-19T (98.4 %) and Streptomyces gramineus JR-43T (98.3 %). Phylogenetic, chemotaxonomic and phenotypic analyses indicated that strain m16T represents a novel species within the genus Streptomyces, for which the name Streptomyces fuscichromogenes is proposed. The type strain is m16T (=CGMCC 4.7110T=KCTC 29195T).

Thermal Inactivation of Foot-and-Mouth Disease Viruses in Suspension▿

PubMed Central

Kamolsiripichaiporn, Somjai; Subharat, Supatsak; Udon, Romphruke; Thongtha, Panithan; Nuanualsuwan, Suphachai

2007-01-01

The heat resistance of foot-and-mouth disease virus (FMDV) strains isolated from outbreaks in Thailand was investigated in phosphate-buffered saline (PBS) at 50, 60, 70, 80, 90, and 100°C. The first-order kinetic model fitted most of the observed linear inactivation curves. The ranges of decimal-reduction time (D value) of FMDV strains at 50, 60, 70, 80, 90, and 100°C were 732 to 1,275 s, 16.37 to 42.00 s, 6.06 to 10.87 s, 2.84 to 5.99 s, 1.65 to 3.18 s, and 1.90 to 2.94 s, respectively. The heat resistances of FMDV strains at lower temperature (50°C) were not serotype specific. The effective inactivating temperature is approximately 60°C. Heat resistances of FMDV strains at 90 and 100°C were not statistically different (P > 0.05), while the FMDV serotype O (OPN) appeared to be the most heat resistant at 60 to 80°C. The other observed inactivation curves were linear with shoulder or tailing (biphasic curves). The shoulder effect was mostly observed at 90 and 100°C, while the tailing effect was mostly observed at 50 to 80°C. The adjusted D values in the case of shoulder and tailing effects did not affect the overall estimated heat resistance of these FMDV strains, so even unadjusted D values of deviant inactivation curves were legitimate. The z values of FMDV serotypes O, A, and Asia 1 were 21.78 to 23.26, 20.75 to 22.79, and 19.87°C, respectively. The z values of FMDV strains studied were not statistically significantly different (P > 0.05). The results of this study indicated that the heat resistance in PBS of FMDV strains from Thailand was much less than had been reported for foreign epidemic FMDV strains. PMID:17660312

[Comparative analysis on the complete genome sequence of mumps epidemic strain and mumps vaccine strain S79 isolated in Zhejiang province, China between year 2005 and 2010].

PubMed

Zhang, Dong-Yan; Feng, Yan; Zhong, Shu-Ling; Lu, Yi-Yu; Zhuang, Fang-Cheng; Xu, Chang-Ping

2012-03-01

To compare the differences in the complete genome sequence between mumps epidemic strain and mumps vaccine strain S79 isolated in Zhejiang province. A total of 4 mumps epidemic strains, which were separated from Zhejiang province during 2005 to 2010, named as ZJ05-1, ZJ06-3, ZJ08-1 and ZJ10-1 were selected in the study. The complete genome sequences were amplified using RT-PCR. The genetic differences between vaccine strain S79 and other genotype strains were compared; while the genetic-distance was calculated and the evolution was analyzed. The biggest difference between the 4 epidemic strains and the vaccine strain S79 was found on the membrane associated protein gene; whose average nucleotide differential number was 42.5 +/- 3.0 and the average variant ratio was 13.6%; while the mean amino acid differential number was 12.8 +/- 1.5 and the average variant ratio was 22.4%. The smallest difference among the 4 epidemic strains and the vaccine strain was found in stromatin genes, whose average nucleotide differential number was 73.8 +/- 2.5 and the average variant ratio was 5.9%; while the mean amino acid differential number was 3.0 +/- 0.8 and the average variant ratio was 0.8%. The dn/ds value of the stromatin genes of the 4 epidemic strains reached the highest, as 0.6526; but without any positive pressure (dn/ds < 1, chi2 = 0.87, P > 0.05). There were mutations happened on the known antigen epitope, as 8th amino acid of membrane associated protein genes and on the 336th and 356th amino acid of hemagglutinin/neuraminidase proteins. Compared with the vaccine strain, the glycosylation sites of ZJ05-1, ZJ06-3, ZJ08-1 and ZJ10-1 increased 1, 1, 2 and 2 respectively. The complete amino acid sequence of all strains showed that there were 17 characteristic sites found on the genotype-F mumps strain. Within the complete genome, the genetic-distance between epidemic strains and vaccine strains in Zhejiang province (0.071) was significantly larger than the genetic-distance between strains in Yunnan province (0.013); the difference showing statistical significance (t = 4.14, P < 0.05). Except nucleocapsid protein genes, all the genes shared similar evolution tree. There were significant differences found in the genes between mumps epidemic strain and mumps vaccine in Zhejiang province.

Phylodynamics of the HIV-1 epidemic in Cuba.

PubMed

Delatorre, Edson; Bello, Gonzalo

2013-01-01

Previous studies have shown that the HIV-1 epidemic in Cuba displayed a complex molecular epidemiologic profile with circulation of several subtypes and circulating recombinant forms (CRF); but the evolutionary and population history of those viral variants remains unknown. HIV-1 pol sequences of the most prevalent Cuban lineages (subtypes B, C and G, CRF18_cpx, CRF19_cpx, and CRFs20/23/24_BG) isolated between 1999 and 2011 were analyzed. Maximum-likelihood analyses revealed multiple introductions of subtype B (n≥66), subtype C (n≥10), subtype G (n≥8) and CRF18_cpx (n≥2) viruses in Cuba. The bulk of HIV-1 infections in this country, however, was caused by dissemination of a few founder strains probably introduced from North America/Europe (clades B(CU-I) and B(CU-II)), east Africa (clade C(CU-I)) and central Africa (clades G(CU), CRF18(CU) and CRF19(CU)), or locally generated (clades CRFs20/23/24_BG). Bayesian-coalescent analyses show that the major HIV-1 founder strains were introduced into Cuba during 1985-1995; whereas the CRFs_BG strains emerged in the second half of the 1990s. Most HIV-1 Cuban clades appear to have experienced an initial period of fast exponential spread during the 1990s and early 2000s, followed by a more recent decline in growth rate. The median initial growth rate of HIV-1 Cuban clades ranged from 0.4 year⁻¹ to 1.6 year⁻¹. Thus, the HIV-1 epidemic in Cuba has been a result of the successful introduction of a few viral strains that began to circulate at a rather late time of the AIDS pandemic, but then were rapidly disseminated through local transmission networks.

Vibrational and optical properties of MoS2: From monolayer to bulk

NASA Astrophysics Data System (ADS)

Molina-Sánchez, Alejandro; Hummer, Kerstin; Wirtz, Ludger

2015-12-01

Molybdenum disulfide, MoS2, has recently gained considerable attention as a layered material where neighboring layers are only weakly interacting and can easily slide against each other. Therefore, mechanical exfoliation allows the fabrication of single and multi-layers and opens the possibility to generate atomically thin crystals with outstanding properties. In contrast to graphene, it has an optical gap of ~1.9 eV. This makes it a prominent candidate for transistor and opto-electronic applications. Single-layer MoS2 exhibits remarkably different physical properties compared to bulk MoS2 due to the absence of interlayer hybridization. For instance, while the band gap of bulk and multi-layer MoS2 is indirect, it becomes direct with decreasing number of layers. In this review, we analyze from a theoretical point of view the electronic, optical, and vibrational properties of single-layer, few-layer and bulk MoS2. In particular, we focus on the effects of spin-orbit interaction, number of layers, and applied tensile strain on the vibrational and optical properties. We examine the results obtained by different methodologies, mainly ab initio approaches. We also discuss which approximations are suitable for MoS2 and layered materials. The effect of external strain on the band gap of single-layer MoS2 and the crossover from indirect to direct band gap is investigated. We analyze the excitonic effects on the absorption spectra. The main features, such as the double peak at the absorption threshold and the high-energy exciton are presented. Furthermore, we report on the the phonon dispersion relations of single-layer, few-layer and bulk MoS2. Based on the latter, we explain the behavior of the Raman-active A1g and E2g1 modes as a function of the number of layers. Finally, we compare theoretical and experimental results of Raman, photoluminescence, and optical-absorption spectroscopy.

Gains and Losses of Transcription Factor Binding Sites in Saccharomyces cerevisiae and Saccharomyces paradoxus.

PubMed

Schaefke, Bernhard; Wang, Tzi-Yuan; Wang, Chuen-Yi; Li, Wen-Hsiung

2015-07-27

Gene expression evolution occurs through changes in cis- or trans-regulatory elements or both. Interactions between transcription factors (TFs) and their binding sites (TFBSs) constitute one of the most important points where these two regulatory components intersect. In this study, we investigated the evolution of TFBSs in the promoter regions of different Saccharomyces strains and species. We divided the promoter of a gene into the proximal region and the distal region, which are defined, respectively, as the 200-bp region upstream of the transcription starting site and as the 200-bp region upstream of the proximal region. We found that the predicted TFBSs in the proximal promoter regions tend to be evolutionarily more conserved than those in the distal promoter regions. Additionally, Saccharomyces cerevisiae strains used in the fermentation of alcoholic drinks have experienced more TFBS losses than gains compared with strains from other environments (wild strains, laboratory strains, and clinical strains). We also showed that differences in TFBSs correlate with the cis component of gene expression evolution between species (comparing S. cerevisiae and its sister species Saccharomyces paradoxus) and within species (comparing two closely related S. cerevisiae strains). © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Identification and Characterization of Staphylococcus aureus Strains with an Incomplete Hemolytic Phenotype.

PubMed

Zhang, Haifang; Zheng, Yi; Gao, Huasheng; Xu, Ping; Wang, Min; Li, Aiqing; Miao, Minhui; Xie, Xiaofang; Deng, Yimai; Zhou, Huiqin; Du, Hong

2016-01-01

Staphylococcus aureus is a common pathogen causing both hospital and community-acquired infections. Hemolysin is one of the important virulence factors for S. aureus and causes the typical β-hemolytic phenotype which is called complete hemolytic phenotype as well. Recently, S. aureus with an incomplete hemolytic phenotype (SIHP) was isolated from clinical samples. To study the microbiologic characteristics of SIHP, the special hemolytic phenotype of SIHP was verified on the sheep blood agar plates supplied by different manufacturers. Expression of hemolysin genes hla, hlb, hlgC , and hld of SIHP was detected by qRT-PCR and it was showed that expression of hlb in SIHP was obviously increased compared to the control S. aureus strains with complete hemolytic phenotype (SCHP), while the expression of hla, hlgC , and hld in SIHP was significantly decreased. In addition, the α-hemolysin encoded by gene hla was decreased obviously in SIHP compared to SCHP by western blot. All 60 SIHP strains were identified to be the methicillin resistant S. aureus (MRSA), and moreover these SIHP strains all contains mecA gene. The virulence gene tst were all present in SIHP, and the intracellular survival ability of SIHP was much greater than that of the gene tst negative S. aureus . We also found that IL-2, IL-6, and IL-17A secreted in the supernatant of SIHP infected macrophages increased significantly compared to tst negative control strains infected ones. MLST analysis showed that all of SIHP strains were classified into ST5 clone. To our knowledge, this study firstly showed that SIHP strains are a kind of methicillin resistant strains which express β-hemolysin highly and possess a potential high virulence, and it was suggested that SIHP should be paid more attention in hospital.

Malic acid production from thin stillage by Aspergillus species.

PubMed

West, Thomas P

2011-12-01

The ability of Aspergillus strains to utilize thin stillage to produce malic acid was compared. The highest malic acid was produced by Aspergillus niger ATCC 9142 at 17 g l(-1). Biomass production from thin stillage was similar with all strains but ATCC 10577 was the highest at 19 g l(-1). The highest malic acid yield (0.8 g g(-1)) was with A. niger ATCC 9142 and ATCC 10577 on the stillage. Thus, thin stillage has the potential to act as a substrate for the commercial production of food-grade malic acid by the A. niger strains. © Springer Science+Business Media B.V. 2011

Zebrafish (Danio rerio) as a screen for attenuation of Lancefield group C streptococci and a model for streptococcal pathogenesis.

PubMed

Borst, L B; Patterson, S K; Lanka, S; Suyemoto, M M; Maddox, C W

2013-05-01

Group C streptococci are highly contagious pyogenic bacteria responsible for respiratory tract, lymph node, urogenital tract, and wound infections. Wild-type strains of Streptococcus equi ssp equi (S. equi) and Streptococcus equi ssp zooepidemicus (S. zoo) as well as a commercially available modified live vaccine strain of S. equi were evaluated for virulence in zebrafish. Survival times, histologic lesions, and relative gene expression were compared among groups. Based on the intramuscular route of infection, significantly shorter survival times were observed in fish infected with wild-type strain when compared to modified live vaccine and S. zoo strains. Histologically, S. zoo-infected fish demonstrated a marked increase in inflammatory infiltrates (predominantly macrophages) at the site of infection, as well as increased cellularity in the spleen and renal interstitium. In contrast, minimal cellular immune response was observed in S. equi-injected fish with local tissue necrosis and edema predominating. Based on whole comparative genomic hybridization, increased transcription of positive acute-phase proteins, coagulation factors, and antimicrobial peptides were observed in S. equi-injected fish relative to S. zoo-injected fish, while mediators of cellular inflammation, including CXC chemokines and granulin, were upregulated in S. zoo-injected fish relative to S. equi-injected fish. In a screen of 11 clinical isolates, S. equi strains with a single nucleotide deletion in the upstream region of szp, a known virulence factor of streptococci, were found to be significantly attenuated in zebrafish. These collective findings underscore the value of the zebrafish as a model of streptococcal pathogenesis.

WE-EF-210-06: Ultrasound 2D Strain Measurement of Radiation-Induced Toxicity: Phantom and Ex Vivo Experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, T; Torres, M; Rossi, P

Purpose: Radiation-induced fibrosis is a common long-term complication affecting many patients following cancer radiotherapy. Standard clinical assessment of subcutaneous fibrosis is subjective and often limited to visual inspection and palpation. Ultrasound strain imaging describes the compressibility (elasticity) of biological tissues. This study’s purpose is to develop a quantitative ultrasound strain imaging that can consistently and accurately characterize radiation-induce fibrosis. Methods: In this study, we propose a 2D strain imaging method based on deformable image registration. A combined affine and B-spline transformation model is used to calculate the displacement of tissue between pre-stress and post-stress B-mode image sequences. The 2D displacementmore » is estimated through a hybrid image similarity measure metric, which is a combination of the normalized mutual information (NMI) and normalized sum-of-squared-differences (NSSD). And 2D strain is obtained from the gradient of the local displacement. We conducted phantom experiments under various compressions and compared the performance of our proposed method with the standard cross-correlation (CC)- based method using the signal-to-noise (SNR) and contrast-to-noise (CNS) ratios. In addition, we conducted ex-vivo beef muscle experiment to further validate the proposed method. Results: For phantom study, the SNR and CNS values of the proposed method were significantly higher than those calculated from the CC-based method under different strains. The SNR and CNR increased by a factor of 1.9 and 2.7 comparing to the CC-based method. For the ex-vivo experiment, the CC-based method failed to work due to large deformation (6.7%), while our proposed method could accurately detect the stiffness change. Conclusion: We have developed a 2D strain imaging technique based on the deformable image registration, validated its accuracy and feasibility with phantom and ex-vivo data. This 2D ultrasound strain imaging technology may be valuable as physicians try to eliminate radiation-induce fibrosis and improve the therapeutic ratio of cancer radiotherapy. This research is supported in part by DOD PCRP Award W81XWH-13-1-0269, and National Cancer Institute (NCI) Grant CA114313.« less

Mutants of Arabidopsis thaliana with decreased amplitude in their phototropic response

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khurana, J.P.; Ren, Zhangling; Steinitz, B.

1989-10-01

Two mutants of Arabidopsis thaliana have been identified with decreased phototropism to 450-nanometer light. Fluence-response relationships for these strains (ZR8 and ZR19) to single and multiple flashes of light show thresholds, curve shapes, and fluence for maximum curvature in first positive phototropism which are the same as those of the wild type. Similarly, there is no alteration from the wild type in the kinetics of curvature or in the optimum dark period separating sequential flashes in a multiple flash regimen. In addition, in both strains, gravitropism is decreased compared to the wild type by an amount which is comparable tomore » the decrease in phototropism. Based on reciprocal backcrosses, it appears that the alteration is due to a recessive nuclear mutation. It is suggested that ZR8 and ZR19 represent alterations in some step analogous to an amplifier, downstream of the photoreceptor pigment, and common to both phototropism and gravitropism.« less

Comprehensive Insights in the Mycobacterium avium subsp. paratuberculosis Genome Using New WGS Data of Sheep Strain JIII-386 from Germany

PubMed Central

Möbius, Petra; Hölzer, Martin; Felder, Marius; Nordsiek, Gabriele; Groth, Marco; Köhler, Heike; Reichwald, Kathrin; Platzer, Matthias; Marz, Manja

2015-01-01

Mycobacterium avium (M. a.) subsp. paratuberculosis (MAP)—the etiologic agent of Johne’s disease—affects cattle, sheep, and other ruminants worldwide. To decipher phenotypic differences among sheep and cattle strains (belonging to MAP-S [Type-I/III], respectively, MAP-C [Type-II]), comparative genome analysis needs data from diverse isolates originating from different geographic regions of the world. This study presents the so far best assembled genome of a MAP-S-strain: Sheep isolate JIII-386 from Germany. One newly sequenced cattle isolate (JII-1961, Germany), four published MAP strains of MAP-C and MAP-S from the United States and Australia, and M. a. subsp. hominissuis (MAH) strain 104 were used for assembly improvement and comparisons. All genomes were annotated by BacProt and results compared with NCBI (National Center for Biotechnology Information) annotation. Corresponding protein-coding sequences (CDSs) were detected, but also CDSs that were exclusively determined by either NCBI or BacProt. A new Shine–Dalgarno sequence motif (5′-AGCTGG-3′) was extracted. Novel CDSs including PE-PGRS family protein genes and about 80 noncoding RNAs exhibiting high sequence conservation are presented. Previously found genetic differences between MAP-types are partially revised. Four of ten assumed MAP-S-specific large sequence polymorphism regions (LSPSs) are still present in MAP-C strains; new LSPSs were identified. Independently of the regional origin of the strains, the number of individual CDSs and single nucleotide variants confirms the strong similarity of MAP-C strains and shows higher diversity among MAP-S strains. This study gives ambiguous results regarding the hypothesis that MAP-S is the evolutionary intermediate between MAH and MAP-C, but it clearly shows a higher similarity of MAP to MAH than to Mycobacterium intracellulare. PMID:26384038

Complete Genome Sequence of Salmonella enterica Serovar Typhimurium Strain YU15 (Sequence Type 19) Harboring the Salmonella Genomic Island 1 and Virulence Plasmid pSTV

PubMed Central

Calva, Edmundo; Puente, José L.; Zaidi, Mussaret B.

2016-01-01

The complete genome of Salmonella enterica subsp. enterica serovar Typhimurium sequence type 19 (ST19) strain YU15, isolated in Yucatán, Mexico, from a human baby stool culture, was determined using PacBio technology. The chromosome contains five intact prophages and the Salmonella genomic island 1 (SGI1). This strain carries the Salmonella virulence plasmid pSTV. PMID:27081132

Genomic Organization and Molecular Analysis of Virulent Bacteriophage 2972 Infecting an Exopolysaccharide-Producing Streptococcus thermophilus Strain

PubMed Central

Lévesque, Céline; Duplessis, Martin; Labonté, Jessica; Labrie, Steve; Fremaux, Christophe; Tremblay, Denise; Moineau, Sylvain

2005-01-01

The Streptococcus thermophilus virulent pac-type phage 2972 was isolated from a yogurt made in France in 1999. It is a representative of several phages that have emerged with the industrial use of the exopolysaccharide-producing S. thermophilus strain RD534. The genome of phage 2972 has 34,704 bp with an overall G+C content of 40.15%, making it the shortest S. thermophilus phage genome analyzed so far. Forty-four open reading frames (ORFs) encoding putative proteins of 40 or more amino acids were identified, and bioinformatic analyses led to the assignment of putative functions to 23 ORFs. Comparative genomic analysis of phage 2972 with the six other sequenced S. thermophilus phage genomes confirmed that the replication module is conserved and that cos- and pac-type phages have distinct structural and packaging genes. Two group I introns were identified in the genome of 2972. They interrupted the genes coding for the putative endolysin and the terminase large subunit. Phage mRNA splicing was demonstrated for both introns, and the secondary structures were predicted. Eight structural proteins were also identified by N-terminal sequencing and/or matrix-assisted laser desorption ionization—time-of-flight mass spectrometry. Detailed analysis of the putative minor tail proteins ORF19 and ORF21 as well as the putative receptor-binding protein ORF20 showed the following interesting features: (i) ORF19 is a hybrid protein, because it displays significant identity with both pac- and cos-type phages; (ii) ORF20 is unique; and (iii) a protein similar to ORF21 of 2972 was also found in the structure of the cos-type phage DT1, indicating that this structural protein is present in both S. thermophilus phage groups. The implications of these findings for phage classification are discussed. PMID:16000821

Discovery and Characterization of Human-Urine Utilization by Asymptomatic-Bacteriuria-Causing Streptococcus agalactiae

PubMed Central

Ipe, Deepak S.; Ben Zakour, Nouri L.; Sullivan, Matthew J.; Beatson, Scott A.; Ulett, Kimberly B.; Benjamin, William H.; Davies, Mark R.; Dando, Samantha J.; King, Nathan P.; Cripps, Allan W.; Dougan, Gordon

2015-01-01

Streptococcus agalactiae causes both symptomatic cystitis and asymptomatic bacteriuria (ABU); however, growth characteristics of S. agalactiae in human urine have not previously been reported. Here, we describe a phenotype of robust growth in human urine observed in ABU-causing S. agalactiae (ABSA) that was not seen among uropathogenic S. agalactiae (UPSA) strains isolated from patients with acute cystitis. In direct competition assays using pooled human urine inoculated with equal numbers of a prototype ABSA strain, designated ABSA 1014, and any one of several UPSA strains, measurement of the percentage of each strain recovered over time showed a markedly superior fitness of ABSA 1014 for urine growth. Comparative phenotype profiling of ABSA 1014 and UPSA strain 807, isolated from a patient with acute cystitis, using metabolic arrays of >2,500 substrates and conditions revealed unique and specific l-malic acid catabolism in ABSA 1014 that was absent in UPSA 807. Whole-genome sequencing also revealed divergence in malic enzyme-encoding genes between the strains predicted to impact the activity of the malate metabolic pathway. Comparative growth assays in urine comparing wild-type ABSA and gene-deficient mutants that were functionally inactivated for the malic enzyme metabolic pathway by targeted disruption of the maeE or maeK gene in ABSA demonstrated attenuated growth of the mutants in normal human urine as well as synthetic human urine containing malic acid. We conclude that some S. agalactiae strains can grow in human urine, and this relates in part to malic acid metabolism, which may affect the persistence or progression of S. agalactiae ABU. PMID:26553467

Proteoglycans in polarized epithelial Madin-Darby canine kidney cells.

PubMed Central

Svennevig, K; Prydz, K; Kolset, S O

1995-01-01

Madin-Darby canine kidney (MDCK) cells were cultured on polycarbonate filters to study the synthesis and sorting of proteoglycans in polarized epithelial cells. Two strains of MDCK cells were used. MDCK I cells resemble distal tubule epithelial cells, and MDCK II cells share some characteristics with proximal tubule cells. Both strains were grown to confluency and labelled with [35S]sulphate for 24 h. The apical and basolateral media and the cell fractions were harvested and analysed by DEAE ion-exchange chromatography. A large portion of the [35S]sulphate-labelled macromolecules bound strongly to the ion-exchange columns, and could be eluted in three distinct peaks. The latest eluting peak was demonstrated to contain almost exclusively chondroitin sulphate, whereas peak 2 contained mostly heparan sulphate, demonstrated by using chondroitinase ABC and nitrous acid (pH 1.5) respectively to depolymerize the [35S]glycosaminoglycan chains. Peak 1 contained negligible amounts of proteoglycans. Large differences could be observed in proteoglycan sorting in MDCK I and II cells. Strain I secreted approx. 67% of the proteoglycans to the apical side and 17% to the basolateral side. The cell fraction contained 17% of the proteoglycans after 24 h of labelling. In contrast, 19% of the proteoglycans were sorted to the apical side of MDCK II cells and 61% to the basolateral side, whereas the cell fraction contained 20%. Furthermore, the level of [35S]proteoglycan biosynthesis (apical and basolateral media and cell fraction total) was higher in MDCK I cells than in strain II. Based on the amount of material degraded by chondroitinase ABC and nitrous acid respectively, and the total amounts of [35S]proteoglycans recovered from the cells, it was calculated that the MDCK I strain synthesized approx. 56% chondroitin sulphate and 44% heparan sulphate. In contrast, the MDCK II strain synthesized 69% heparan sulphate and 31% chondroitin sulphate. To further identify the [35S]proteoglycans synthesized by MDCK I and II cells, antibodies against perlecan, versican and syndecan were used. The antibody against mouse syndecan did not cross-react with any of the proteoglycans produced in MDCK I or II cells. Both MDCK I and II cells expressed perlecan; 57-61% could be recovered from the basolateral fractions and 18-34% from the apical medium. Versican was also found in both MDCK I and II cells. Compared with perlecan, a larger percentage of versican (43-53%) was found in the cell fractions. Images Figure 3 Figure 4 Figure 5 Figure 6 PMID:7487945

Increased longitudinal contractility and diastolic function at rest in well-trained amateur Marathon runners: a speckle tracking echocardiography study

PubMed Central

2014-01-01

Background Regular physical activity reduces cardiovascular risk. There is concern that Marathon running might acutely damage the heart. It is unknown to what extent intensive physical endurance activity influences the cardiac mechanics at resting condition. Methods Eighty-four amateur marathon runners (43 women and 41 men) from Berlin-Brandenburg area who had completed at least one marathon previously underwent clinical examination and echocardiography at least 10 days before the Berlin Marathon at rest. Standard transthoracic echocardiography and 2D strain and strain rate analysis were performed. The 2D Strain and strain rate values were compared to previous published data of healthy untrained individuals. Results The average global longitudinal peak systolic strain of the left ventricle was -23 +/- 2% with peak systolic strain rate -1.39 +/- 0.21/s, early diastolic strain rate 2.0 +/- 0.40/s and late diastolic strain rate 1.21 +/- 0.31/s. These values are significantly higher compared to the previous published values of normal age-adjusted individuals. In addition, no age-related decline of longitudinal contractility in well-trained athletes was observed. Conclusions There is increased overall longitudinal myocardial contractility at rest in experienced endurance athletes compared to the published normal values in the literature indicating a preserved and even supra-normal contractility in the athletes. There is no age dependent decline of the longitudinal 2D Strain values. This underlines the beneficial effects of regular physical exercise even in advanced age. PMID:24571726

Comparison of Genotypes of Salmonella enterica Serovar Enteritidis Phage Type 30 and 9c Strains Isolated during Three Outbreaks Associated with Raw Almonds▿

PubMed Central

Parker, Craig T.; Huynh, Steven; Quiñones, Beatriz; Harris, Linda J.; Mandrell, Robert E.

2010-01-01

In 2000 to 2001, 2003 to 2004, and 2005 to 2006, three outbreaks of Salmonella enterica serovar Enteritidis were linked with the consumption of raw almonds. The S. Enteritidis strains from these outbreaks had rare phage types (PT), PT30 and PT9c. Clinical and environmental S. Enteritidis strains were subjected to pulsed-field gel electrophoresis (PFGE), multilocus variable-number tandem repeat analysis (MLVA), and DNA microarray-based comparative genomic indexing (CGI) to evaluate their genetic relatedness. All three methods differentiated these S. Enteritidis strains in a manner that correlated with PT. The CGI analysis confirmed that the majority of the differences between the S. Enteritidis PT9c and PT30 strains corresponded to bacteriophage-related genes present in the sequenced genomes of S. Enteritidis PT4 and S. enterica serovar Typhimurium LT2. However, PFGE, MLVA, and CGI failed to discriminate between S. Enteritidis PT30 strains related to outbreaks from unrelated clinical strains or between strains separated by up to 5 years. However, metabolic fingerprinting demonstrated that S. Enteritidis PT4, PT8, PT13a, and clinical PT30 strains metabolized l-aspartic acid, l-glutamic acid, l-proline, l-alanine, and d-alanine amino acids more efficiently than S. Enteritidis PT30 strains isolated from orchards. These data indicate that S. Enteritidis PT9c and 30 strains are highly related genetically and that PT30 orchard strains differ from clinical PT30 strains metabolically, possibly due to fitness adaptations. PMID:20363782

Severe streptococcal infections in historical perspective.

PubMed

Katz, A R; Morens, D M

1992-01-01

The recent unexplained increase in severe streptococcal diseases in the United States and Great Britain is compared to the 1825-1885 pandemic of fatal scarlet fever. Although scarlet fever may not be representative of all severe streptococcal disease, it was the only one reliably identified in the 19th century. The epidemiology of scarlet fever during the 19th century pandemic suggests the following features of the disease; cocirculation of both virulent and less-virulent streptococcal strains eliciting cross-immunity; circulation of hyperendemic prevalent strains in urban centers of developed nations, with periodic spillovers to rural areas and developing nations; and protection of infants from infection (but not from fatal disease once infection occurred) by the transfer of maternal antibodies via the placenta, breast milk, or both. The 19th century data suggest that efforts to prevent severe streptococcal diseases should begin with better characterization of the epidemiology of streptococcal disease, a task entailing identification of streptococcal virulence factors and measurement of their distribution among isolates from individuals with streptococcal diseases and in open populations.

Roseomonas rubra sp. nov., isolated from lagoon sediments.

PubMed

Subhash, Y; Bang, John J; You, Taek H; Lee, Sang-Seob

2016-10-01

A novel Gram-stain-negative, coccus to oval-shaped, non-motile bacterium, designated strain S5T, was isolated from lagoon sediments collected from North Carolina, USA. Strain S5T was able to grow at 12-45 °C (optima, 30-37 °C) and at pH 6.3-9.0 (optima, 6.5-7.5). No added NaCl was required for growth of strain S5T. Strain S5T was positive for catalase and oxidase activity. C18 : 1ω6c/C18 : 1ω7c, C16 : 1ω6c/C16 : 1ω7c and C16 : 0 were predominant fatty acids with minor amounts of C8 : 0 3-OH, C14 : 0, C16 : 0 3-OH, C18 : 1 2-OH, C14 : 1ω5c, C16 : 1ω5c and C19 : 0 cyclo ω8c. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and an unidentified glycolipid were major polar lipids. Minor amounts of an unidentified amino lipid and three unidentified lipids were also detected. The G+C content of the genomic DNA was 73.5 mol%. 16S rRNA gene sequence comparisons indicated that strain S5T represents a member of the genus Roseomonas within the family Acetobacteraceae of the class Alphaproteobacteria. Strain S5T had a sequence similarity of 97.80 % with Roseomonas rhizosphaerae YW11T, 97.69 % with Roseomonas aestuarii JC17T and <97 % with other members of the genus Roseomonas. However, strain S5T showed only 45.2±2 and 17±2 % relatedness (based on DNA-DNA hybridization) with R. rhizosphaerae KACC 17225T (=YW11T) and R. aestuarii KCTC 22692T (=JC17T), respectively. Distinct morphological, physiological and genotypic differences from previously described taxa support the classification of strain S5T as a representative of a novel species in the genus Roseomonas, for which the name Roseomonas rubra sp. nov. is proposed. The type strain is S5T (=KEMB 563-468T=JCM 31177T).

Superelasticity, corrosion resistance and biocompatibility of the Ti-19Zr-10Nb-1Fe alloy.

PubMed

Xue, Pengfei; Li, Yan; Li, Kangming; Zhang, Deyuan; Zhou, Chungen

2015-05-01

Microstructure, mechanical properties, superelasticity and biocompatibility of a Ti-19Zr-10Nb-1Fe alloy are investigated. X-ray diffraction spectroscopy and transmission electron microscopy observations show that the as-cast Ti-19Zr-10Nb-1Fe alloy is composed of α' and β phases, but only the β phase exists in the as-rolled and as-quenched alloys. The tensile stress-strain tests indicate that the as-quenched alloy exhibits a good combination of mechanical properties with a large elongation of 25%, a low Young's modulus of 59 GPa and a high ultimate tensile stress of 723 MPa. Superelastic recovery behavior is found in the as-quenched alloy during tensile tests, and the corresponding maximum of superelastic strain is 4.7% at the pre-strain of 6%. A superelastic recovery of 4% with high stability is achieved after 10 cyclic loading-unloading training processes. Potentiodynamic polarization and ion release measurements indicate that the as-quenched alloy shows a lower corrosion rate in Hank's solution and a much less ion release rate in 0.9% NaCl solution than those of the NiTi alloys. Cell culture results indicate that the osteoblasts' adhesion and proliferation are similar on both the Ti-19Zr-10Nb-1Fe and NiTi alloys. A better hemocompatibility is confirmed for the as-quenched Ti-19Zr-10Nb-1Fe alloy, attributed to more stable platelet adhesion and small activation degree, and a much lower hemolysis rate compared with the NiTi alloy. Copyright © 2015 Elsevier B.V. All rights reserved.

Mechanism, stability and fitness cost of resistance to pyriproxyfen in the house fly, Musca domestica L. (Diptera: Muscidae).

PubMed

Shah, Rizwan Mustafa; Shad, Sarfraz Ali; Abbas, Naeem

2015-03-01

Pyriproxyfen, a bio-rational insecticide, used worldwide for the management of many insect pests including the house fly, Musca domestica. To devise a retrospective resistance management strategy, biological parameters of pyriproxyfen resistant (Pyri-SEL), unselected (UNSEL), Cross1 and Cross2M. domestica strains were studied in the laboratory. Additionally, the stability and mechanism of resistance was also investigated. After 30 generations of pyriproxyfen selection, a field-collected strain developed 206-fold resistance compared with susceptible strain. Synergists such as piperonyl butoxide and S,S,S-tributylphosphorotrithioate did not alter the LC50 values, suggesting another cause of target site resistance to pyriproxyfen in the Pyri-SEL strain. The resistance to all tested insecticides was unstable in Pyri-SEL strain. The relative fitness of 0.51 with lower fecundity, hatchability, lower number of next generation larvae, reduced mean population growth rate and net reproductive rate were observed in the Pyri-SEL strain compared with the UNSEL strain. The cost of fitness associated with pyriproxyfen resistance was evident in Pyri-SEL strain. The present study provides useful information for making pro-active resistance management strategies to delay resistance development. Copyright © 2015 Elsevier Inc. All rights reserved.

RNA Sequencing Reveals Differences between the Global Transcriptomes of Salmonella enterica Serovar Enteritidis Strains with High and Low Pathogenicities

PubMed Central

2014-01-01

Salmonella enterica serovar Enteritidis is one of the important causes of bacterial food-borne gastroenteritis worldwide. Field strains of S. Enteritidis are relatively genetically homogeneous; however, they show extensive phenotypic diversity and differences in virulence potential. RNA sequencing (RNA-Seq) was used to characterize differences in the global transcriptome between several genetically similar but phenotypically diverse poultry-associated field strains of S. Enteritidis grown in laboratory medium at avian body temperature (42°C). These S. Enteritidis strains were previously characterized as high-pathogenicity (HP; n = 3) and low-pathogenicity (LP; n = 3) strains based on both in vitro and in vivo virulence assays. Using the negative binomial distribution-based statistical tools edgeR and DESeq, 252 genes were identified as differentially expressed in LP strains compared with their expression in the HP strains (P < 0.05). A majority of genes (235, or 93.2%) showed significantly reduced expression, whereas a few genes (17, or 6.8%) showed increased expression in all LP strains compared with HP strains. LP strains showed a unique transcriptional profile that is characterized by significantly reduced expression of several transcriptional regulators and reduced expression of genes involved in virulence (e.g., Salmonella pathogenicity island 1 [SPI-1], SPI-5, and fimbrial and motility genes) and protection against osmotic, oxidative, and other stresses, such as iron-limiting conditions commonly encountered within the host. Several functionally uncharacterized genes also showed reduced expression. This study provides a first concise view of the global transcriptional differences between field strains of S. Enteritidis with various levels of pathogenicity, providing the basis for future functional characterization of several genes with potential roles in virulence or stress regulation of S. Enteritidis. PMID:24271167

[Mycobacterium tuberculosis strain transmission caused by migratory processes in the Russian Federation (in case of populational migration from the Caucasian Region to Moscow and the Moscow Region)].

PubMed

Andreevskaia, S N; Chernousova, L N; Smirnova, T G; Larionova, E E; Kuz'min, A V

2006-01-01

The investigation was carried out on 134 M. tuberculosis isolated from 134 patients treated at the Central Research Institute of Tuberculosis, Russian Academy of Medical Sciences. The patients were divided into 2 groups: 1) those who were natives of Moscow and the Moscow Region (MR patients); 2) those who were migrants to the Moscow Region from Azerbaijan, Daghestan, Chechnya, Ingushetia, Karachai-Cherkessia, North Ossetia (the Caucasian Region) (CR patients) who had fallen in the place of birth. Genotyping by the polymorphism of lengths of the restriction fragments containing the insertion sequence IS6110 revealed a genetic diversity of M. tuberculosis strains. The examined M. tuberculosis strains belonged to 13 genotypic families. The W and AI families were prevalent. The family W M. tuberculosis strains isolated from the Caucasians were highly clustered, as confirmed by the overwhelming predominance of the strain variant W148 (19.7%). The spectrum of the strain variants of the W family, and those of the AI family in particular, greatly differed in MR and CR patients. Only one strain variant AI12 occurring both in MR and CR patients was detected. A study of the transmission activity coefficient (TAC) of the families W and AI indicated that the transmission activity of W strains was significantly higher than that of M. tuberculosis strains of the AI family. A comparative analysis of the TAC of M. tuberculosis strains of the AI family demonstrated that the transmission activity of the strains of this family was identical no matter where a patient had fallen ill (1.59 and 1.41% in the Moscow and Caucasian Regions, respectively). Unlike M. tuberculosis strains of the AI family, the TAC of W strains isolated from the patients infected in the Moscow Region (28.17 and 19.05%, respectively), which suggests the more intensive transmission of the pathogen M. tuberculosis of the W family in the Caucasian Region.

A peptide resource for the analysis of Staphylococcus aureus in host pathogen interaction studies

PubMed Central

Depke, Maren; Michalik, Stephan; Rabe, Alexander; Surmann, Kristin; Brinkmann, Lars; Jehmlich, Nico; Bernhardt, Jörg; Hecker, Michael; Wollscheid, Bernd; Sun, Zhi; Moritz, Robert L.; Völker, Uwe; Schmidt, Frank

2016-01-01

Staphylococcus aureus is an opportunistic human pathogen, which can cause life-threatening disease. Proteome analyses of the bacterium can provide new insights into its pathophysiology and important facets of metabolic adaptation and, thus, aid the recognition of targets for intervention. However, the value of such proteome studies increases with their comprehensiveness. We present an MS–driven, proteome-wide characterization of the strain S. aureus HG001. Combining 144 high precision proteomic data sets, we identified 19 109 peptides from 2088 distinct S. aureus HG001 proteins, which account for 72% of the predicted ORFs. Peptides were further characterized concerning pI, GRAVY, and detectability scores in order to understand the low peptide coverage of 8.7% (19 109 out of 220 245 theoretical peptides). The high quality peptide-centric spectra have been organized into a comprehensive peptide fragmentation library (SpectraST) and used for identification of S. aureus-typic peptides in highly complex host–pathogen interaction experiments, which significantly improved the number of identified S. aureus proteins compared to a MASCOT search. This effort now allows the elucidation of crucial pathophysiological questions in S. aureus-specific host–pathogen interaction studies through comprehensive proteome analysis. The S. aureus-specific spectra resource developed here also represents an important spectral repository for SRM or for data-independent acquisition MS approaches. All MS data have been deposited in the ProteomeXchange with identifier PXD000702 (http://proteomecentral.proteomexchange.org/dataset/PXD000702). PMID:26224020

A peptide resource for the analysis of Staphylococcus aureus in host-pathogen interaction studies.

PubMed

Depke, Maren; Michalik, Stephan; Rabe, Alexander; Surmann, Kristin; Brinkmann, Lars; Jehmlich, Nico; Bernhardt, Jörg; Hecker, Michael; Wollscheid, Bernd; Sun, Zhi; Moritz, Robert L; Völker, Uwe; Schmidt, Frank

2015-11-01

Staphylococcus aureus is an opportunistic human pathogen, which can cause life-threatening disease. Proteome analyses of the bacterium can provide new insights into its pathophysiology and important facets of metabolic adaptation and, thus, aid the recognition of targets for intervention. However, the value of such proteome studies increases with their comprehensiveness. We present an MS-driven, proteome-wide characterization of the strain S. aureus HG001. Combining 144 high precision proteomic data sets, we identified 19 109 peptides from 2088 distinct S. aureus HG001 proteins, which account for 72% of the predicted ORFs. Peptides were further characterized concerning pI, GRAVY, and detectability scores in order to understand the low peptide coverage of 8.7% (19 109 out of 220 245 theoretical peptides). The high quality peptide-centric spectra have been organized into a comprehensive peptide fragmentation library (SpectraST) and used for identification of S. aureus-typic peptides in highly complex host-pathogen interaction experiments, which significantly improved the number of identified S. aureus proteins compared to a MASCOT search. This effort now allows the elucidation of crucial pathophysiological questions in S. aureus-specific host-pathogen interaction studies through comprehensive proteome analysis. The S. aureus-specific spectra resource developed here also represents an important spectral repository for SRM or for data-independent acquisition MS approaches. All MS data have been deposited in the ProteomeXchange with identifier PXD000702 (http://proteomecentral.proteomexchange.org/dataset/PXD000702). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Genetic studies on reference strains of mutans streptococci.

PubMed

Ota, Fusao; Yamato, Masayuki; Hayashi, Mie; Ota, Masayuki; Koga, Tetsuro; Sherin, Ahmed; Mukai, Chiharu; Sakai, Kentaro; Yamamoto, Shigeru

2002-01-01

Twenty four reference strains (serotype a-h) belonging to the mutans group of streptococci were compared for DNA fragment patterns of rDNA after treatment with Hind III. It was shown that Streptococcus cricetus (serotype a), S. rattus (serotype b), and S. downei (serotype h) reveals comparatively homogeneous patterns while S. mutans (serotype c, e and f) exhibits differences between the different serotypes as well as within single serotypes. S. sobrinus had an intermediary diversity. These data support the previous findings that S. mutans is heterogeneous at the serological, biochemical and genetical level.

Hansschlegelia beijingensis sp. nov., an aerobic, pink-pigmented, facultatively methylotrophic bacterium isolated from watermelon rhizosphere soil.

PubMed

Zou, Xiao-lin; Li, Xiu-ai; Wang, Xu-Ming; Chen, Qiang; Gao, Miao; Qiu, Tian-lei; Sun, Jian-guang; Gao, Jun-lian

2013-10-01

A novel Gram-stain-negative, aerobic, rod-shaped strain designated PG04(T) was isolated from the rhizosphere of watermelon plants cultivated in Beijing, China. A polyphasic taxonomic study was performed on the new isolate. On the basis of 16S rRNA gene sequence similarity studies, isolate PG04(T) belonged clearly to the genus Hansschlegelia and was most closely related to Hansschlegelia zhihuaiae (97.3 % similarity to the type strain). The predominant respiratory quinone was ubiquinone 10 (Q-10) and the polar lipid profile was composed of the major lipids diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and phosphatidylcholine. The major fatty acids were C18 : 1ω7c (41.3 %), C19 : 0 cyclo ω8c (30.6 %) and C16 : 0 (19.1 %). The G+C content of the DNA was about 64.4 mol%. DNA-DNA hybridization experiments showed 34.4 % relatedness between strain PG04(T) and H. zhihuaiae DSM 18984(T). The results of physiological and biochemical tests and differences in fatty acid profiles allowed clear phenotypic differentiation of strain PG04(T) from the most closely related species in the genus, H. zhihuaiae. Strain PG04(T) therefore represents a novel species within the genus Hansschlegelia, for which the name Hansschlegelia beijingensis sp. nov. is proposed, with the type strain PG04(T) ( = DSM 25481(T) = ACCC 05759(T)).

Genotypic diversity of oscillatoriacean strains belonging to the genera Geitlerinema and Spirulina determined by 16S rDNA restriction analysis.

PubMed

Margheri, Maria C; Piccardi, Raffaella; Ventura, Stefano; Viti, Carlo; Giovannetti, Luciana

2003-05-01

Genotypic diversity of several cyanobacterial strains mostly isolated from marine or brackish waters, belonging to the genera Geitlerinema and Spirulina, was investigated by amplified 16S ribosomal DNA restriction analysis and compared with morphological features and response to salinity. Cluster analysis was performed on amplified 16S rDNA restriction profiles of these strains along with profiles obtained from sequence data of five Spirulina-like strains, including three representatives of the new genus Halospirulina. Our strains with tightly coiled trichomes from hypersaline waters could be assigned to the Halospirulina genus. Among the uncoiled strains, the two strains of hypersaline origin clustered together and were found to be distant from their counterparts of marine and freshwater habitat. Moreover, another cluster, formed by alkali-tolerant strains with tightly coiled trichomes, was well delineated.

Intraspecific variability of Steinernema feltiae strains from Cemoro Lawang, eastern Java, Indonesia.

PubMed

Addis, T; Mulawarman, M; Waeyenberge, L; Moens, M; Viaene, N; Ehlers, R U

2010-01-01

Four strains of Steinernema feltiae from Eastern Java, Indonesia were characterized based on morphometric, morphological and molecular data. In addition, their virulence against last instar Tenebrio molitor and heat tolerance was tested. Infective juvenile have a mean body length ranging from 749 to 792 microm. The maximum sequence difference among the four strains was 7 bp (8.8%) in the ITS and 2 bp (0.3%) in D2D3 regions of the rDNA. All the strains are not reproductively isolated and can reproduce with European strain S. feltiae Owiplant. The lowest LC50 was observed for strain SCM (373) and the highest for S. feltiae strain Owiplant (458) IJs/40 T. molitor. All four strains showed relatively better mean heat tolerance when compared with S. feltiae Owiplant, both in adapted and non-adapted heat tolerance experiments.

Differentiation of highly virulent strains of Streptococcus suis serotype 2 according to glutamate dehydrogenase electrophoretic and sequence type.

PubMed

Kutz, Russell; Okwumabua, Ogi

2008-10-01

The glutamate dehydrogenase (GDH) enzymes of 19 Streptococcus suis serotype 2 strains, consisting of 18 swine isolates and 1 human clinical isolate from a geographically varied collection, were analyzed by activity staining on a nondenaturing gel. All seven (100%) of the highly virulent strains tested produced an electrophoretic type (ET) distinct from those of moderately virulent and nonvirulent strains. By PCR and nucleotide sequence determination, the gdh genes of the 19 strains and of 2 highly virulent strains involved in recent Chinese outbreaks yielded a 1,820-bp fragment containing an open reading frame of 1,344 nucleotides, which encodes a protein of 448 amino acid residues with a calculated molecular mass of approximately 49 kDa. The nucleotide sequences contained base pair differences, but most were silent. Cluster analysis of the deduced amino acid sequences separated the isolates into three groups. Group I (ETI) consisted of the seven highly virulent isolates and the two Chinese outbreak strains, containing Ala(299)-to-Ser, Glu(305)-to-Lys, and Glu(330)-to-Lys amino acid substitutions compared with groups II and III (ETII). Groups II and III consisted of moderately virulent and nonvirulent strains, which are separated from each other by Tyr(72)-to-Asp and Thr(296)-to-Ala substitutions. Gene exchange studies resulted in the change of ETI to ETII and vice versa. A spectrophotometric activity assay for GDH did not show significant differences between the groups. These results suggest that the GDH ETs and sequence types may serve as useful markers in predicting the pathogenic behavior of strains of this serotype and that the molecular basis for the observed differences in the ETs was amino acid substitutions and not deletion, insertion, or processing uniqueness.

Systemic Screening of Strains of the Lion's Mane Medicinal Mushroom Hericium erinaceus (Higher Basidiomycetes) and Its Protective Effects on Aβ-Triggered Neurotoxicity in PC12 Cells.

PubMed

Liu, Zongying; Wang, Qinglong; Cui, Jian; Wang, Lili; Xiong, Lili; Wang, Wei; Li, Diqiang; Liu, Na; Wu, Yiran; Mao, Canquan

2015-01-01

Hericium erinaceus possesses multiple medicinal values. To date, however, there have been few studies of the systemic screening of H. erinaceus strains, and the neuroprotective effects of H. erinaceus prepared from homogenized, fresh fruiting bodies are not fully understood. In this study, 4 random primers were selected and used in random amplified polymorphic DNA (RAPD) polymerase chain reaction (PCR) to screen and evaluate the genetic diversity of 19 commercial strains of H. erinaceus from different localities in China. A total of 66 bands were obtained, and the percentage of polymorphic loci reached 80.30%. Five dendrograms were constructed based on RAPD by Jaccard cluster and within-group linkage analysis. Primer S20 as well as all 4 primers had great potential as specific primers for RAPD-PCR molecular identification and differentiation of H. erinaceus strains. Based on the results of submerged culture and fruiting body cultivation, strains HT-N, HT-J1, HT-C, and HT-M were identified as superior among the 19 H. erinaceus strains. Further study showed that the oral preparation of homogenized, fresh fruiting bodies of H. erinaceus could attenuate the Aβ25-35-triggered damage in PC12 cells by significantly increasing cell viability and by decreasing the release of lactate dehydrogenase. In conclusion, RAPD-PCR combined with liquid and solid cultures can be used well in the screening and identification of H. erinaceus strains, and products prepared from homogenized, fresh fruiting bodies of H. erinaceus had neuroprotective effects on PC12 cells.

Study on biofilm-forming properties of clinical isolates of Staphylococcus aureus.

PubMed

Taj, Yasmeen; Essa, Farhan; Aziz, Faisal; Kazmi, Shahana Urooj

2012-05-14

The purpose of this study was to observe the formation of biofilm, an important virulence factor, by isolates of Staphylococcus aureus (S. aureus) in Pakistan by different conventional methods and through electron microscopy. We screened 115 strains of S. aureus isolated from different clinical specimens by tube method (TM), air-liquid interface coverslip assay method, Congo red agar (CRA) method, and scanning electron microscopy (SEM). Out of 115 S. aureus isolates, 63 (54.78%) showed biofilm formation by tube method. Biofilm forming bacteria were further categorized as high producers (n = 23, 20%) and moderate producers (n = 40, 34.78%). TM coordinated well with the coverslip assay for strong biofilm-producing strains in 19 (16.5%) isolates. By coverslip method, weak producers were difficult to differentiate from biofilm negative isolates. Screening on CRA showed biofilm formation only in four (3.47%) strains. Scanning electron micrographs showed the biofilm-forming strains of S. aureus arranged in a matrix on the propylene surface and correlated well with the TM. Biofilm production is a marker of virulence for clinically relevant staphylococcal infections. It can be studied by various methods but screening on CRA is not recommended for investigation of biofilm formation in Staphylococcus aureus. Electron micrograph images correlate well with the biofilm production as observed by TM.

Cross protective immune responses in nursing piglets infected with a US spike-insertion deletion porcine epidemic diarrhea virus strain and challenged with an original US PEDV strain.

PubMed

Annamalai, Thavamathi; Lin, Chun-Ming; Gao, Xiang; Liu, Xinsheng; Lu, Zhongyan; Saif, Linda J; Wang, Qiuhong

2017-10-06

We investigated cross-protective immunity of a US spike-insertion deletion porcine epidemic diarrhea virus (PEDV) Iowa106 (S-INDEL) strain against the original US PEDV (PC21A) strain in nursing piglets. Piglets were inoculated orally with S-INDEL, PC21A or mock. At 20-29 days post-inoculation (dpi), all pigs were challenged with the PC21A strain. The S-INDEL-inoculated pigs had lower ileal IgA antibody secreting cells, serum IgA and neutralizing antibody titers compared with PC21A-inoculated pigs. No pigs in the PC21A-group developed diarrhea, whereas 81 and 100% of pigs in the S-INDEL and mock-groups had diarrhea post challenge, respectively. S-INDEL induced partial protective immunity against the original US PEDV strain.

Effect of Different Loading Conditions on the Nucleation and Development of Shear Zones Around Material Heterogeneities

NASA Astrophysics Data System (ADS)

Rybacki, E.; Nardini, L.; Morales, L. F.; Dresen, G.

2017-12-01

Rock deformation at depths in the Earth's crust is often localized in high temperature shear zones, which occur in the field at different scales and in a variety of lithologies. The presence of material heterogeneities has long been recognized to be an important cause for shear zones evolution, but the mechanisms controlling initiation and development of localization are not fully understood, and the question of which loading conditions (constant stress or constant deformation rate) are most favourable is still open. To better understand the effect of boundary conditions on shear zone nucleation around heterogeneities, we performed a series of torsion experiments under constant twist rate (CTR) and constant torque (CT) conditions in a Paterson-type deformation apparatus. The sample assemblage consisted of copper-jacketed Carrara marble hollow cylinders with one weak inclusion of Solnhofen limestone. The CTR experiments were performed at maximum bulk strain rates of 1.8-1.9*10-4 s-1, yielding shear stresses of 19-20 MPa. CT tests were conducted at shear stresses between 18.4 and 19.8 MPa resulting in shear strain rates of 1-2*10-4 s-1. All experiments were run at 900 °C temperature and 400 MPa confining pressure. Maximum bulk shear strains (γ) were ca. 0.3 and 1. Strain localized within the host marble in front of the inclusion in an area termed process zone. Here grain size reduction is intense and local shear strain (estimated from markers on the jackets) is up to 8 times higher than the applied bulk strain, rapidly dropping to 2 times higher at larger distance from the inclusion. The evolution of key microstructural parameters such as average grain size and average grain orientation spread (GOS, a measure of lattice distortion) within the process zone, determined by electron backscatter diffraction analysis, differs significantly as a function of loading conditions. Both parameters indicate that, independent of bulk strain and distance from the inclusion, the contribution of small strain-free recrystallized grains is larger in CTR than in CT samples. Our results suggest that loading conditions substantially affect material heterogeneity-induced localization in its nucleation and transient stages.

Characterization of human passive muscles for impact loads using genetic algorithm and inverse finite element methods.

PubMed

Chawla, A; Mukherjee, S; Karthikeyan, B

2009-02-01

The objective of this study is to identify the dynamic material properties of human passive muscle tissues for the strain rates relevant to automobile crashes. A novel methodology involving genetic algorithm (GA) and finite element method is implemented to estimate the material parameters by inverse mapping the impact test data. Isolated unconfined impact tests for average strain rates ranging from 136 s(-1) to 262 s(-1) are performed on muscle tissues. Passive muscle tissues are modelled as isotropic, linear and viscoelastic material using three-element Zener model available in PAMCRASH(TM) explicit finite element software. In the GA based identification process, fitness values are calculated by comparing the estimated finite element forces with the measured experimental forces. Linear viscoelastic material parameters (bulk modulus, short term shear modulus and long term shear modulus) are thus identified at strain rates 136 s(-1), 183 s(-1) and 262 s(-1) for modelling muscles. Extracted optimal parameters from this study are comparable with reported parameters in literature. Bulk modulus and short term shear modulus are found to be more influential in predicting the stress-strain response than long term shear modulus for the considered strain rates. Variations within the set of parameters identified at different strain rates indicate the need for new or improved material model, which is capable of capturing the strain rate dependency of passive muscle response with single set of material parameters for wide range of strain rates.

Isolation and characterization of a novel simazine-degrading bacterium from agricultural soil of central Chile, Pseudomonas sp. MHP41.

PubMed

Hernández, Marcela; Villalobos, Patricio; Morgante, Verónica; González, Myriam; Reiff, Caroline; Moore, Edward; Seeger, Michael

2008-09-01

s-Triazine herbicides are used extensively in South America in agriculture and forestry. In this study, a bacterium designated as strain MHP41, capable of degrading simazine and atrazine, was isolated from agricultural soil in the Quillota valley, central Chile. Strain MHP41 is able to grow in minimal medium, using simazine as the sole nitrogen source. In this medium, the bacterium exhibited a growth rate of mu=0.10 h(-1), yielding a high biomass of 4.2 x 10(8) CFU mL(-1). Resting cells of strain MHP41 degrade more than 80% of simazine within 60 min. The atzA, atzB, atzC, atzD, atzE and atzF genes encoding the enzymes of the simazine upper and lower pathways were detected in strain MHP41. The motile Gram-negative bacterium was identified as a Pseudomonas sp., based on the Biolog microplate system and comparative sequence analyses of the 16S rRNA gene. Amplified ribosomal DNA restriction analysis allowed the differentiation of strain MHP41 from Pseudomonas sp. ADP. The comparative 16S rRNA gene sequence analyses suggested that strain MHP41 is closely related to Pseudomonas nitroreducens and Pseudomonas multiresinovorans. This is the first s-triazine-degrading bacterium isolated in South America. Strain MHP41 is a potential biocatalyst for the remediation of s-triazine-contaminated environments.

Systolic Strain Abnormalities to Predict Hospital Readmission in Patients With Heart Failure and Normal Ejection Fraction

PubMed Central

Borer, Steven M.; Kokkirala, Aravind; O'Sullivan, David M.; Silverman, David I.

2011-01-01

Background Despite intensive investigation, the pathogenesis of heart failure with normal ejection fraction (HFNEF) remains unclear. We hypothesized that subtle abnormalities of systolic function might play a role, and that abnormal systolic strain and strain rate would provide a marker for adverse outcomes. Methods Patients of new CHF and left ventricular ejection fraction > 50% were included. Exclusion criteria were recent myocardial infarction, severe valvular heart disease, severe left ventricular hypertrophy (septum >1.8 cm), or a technically insufficient echocardiogram. Average peak systolic strain and strain rate were measured using an off-line grey scale imaging technique. Systolic strain and strain rate for readmitted patients were compared with those who remained readmission-free. Results One hundred consecutive patients with a 1st admission for HFNEF from January 1, 2004 through December 31, 2007, inclusive, were analyzed. Fifty two patients were readmitted with a primary diagnosis of heart failure. Systolic strain and strain rates were reduced in both study groups compared to controls. However, systolic strain did not differ significantly between the two groups (-11.7% for those readmitted compared with -12.9% for those free from readmission, P = 0.198) and systolic strain rates also were similar (-1.05 s-1 versus -1.09 s-1, P = 0.545). E/e’ was significantly higher in readmitted patients compared with those who remained free from readmission (14.5 versus 11.0, P = 0.013). E/e’ (OR 1.189, 95% CI 1.026-1.378; P = 0.021) was found to be an independent predictor for HFNEF readmission. Conclusions Among patients with new onset HFNEF, SS and SR rates are reduced compared with patients free of HFNEF, but do not predict hospital readmission. Elevated E/e’ is a predictor of readmission in these patients. PMID:28352395

Improvement of the Texture of Yogurt by Use of Exopolysaccharide Producing Lactic Acid Bacteria.

PubMed

Han, Xue; Yang, Zhe; Jing, Xueping; Yu, Peng; Zhang, Yingchun; Yi, Huaxi; Zhang, Lanwei

2016-01-01

19 Streptococcus thermophilus with high exopolysaccharide production were isolated from traditional Chinese fermented dairy products. The exopolysaccharide and viscosity of milk fermented by these 19 isolates were assayed. The strains of Streptococcus thermophilus zlw TM11 were selected because its fermented milk had the highest exopolysaccharide content (380 mg/L) and viscosity (7716 mpa/s). Then Streptococcus thermophilus zlw TM11 was combined with Lactobacillus delbrueckii subsp. bulgaricus 3 4.5 and the combination was named SH-1. The quality of the yogurt fermented by SH-1 and two commercial starter cultures (YO-MIX 465, YF-L711) were compared. It was shown that the exopolysaccharide content of yogurt fermented by SH-1 was similar to that of yogurt fermented by YF-L711 and significantly higher than YO-MIX 465 (p < 0.05). In addition, the yogurt fermented by SH-1 had the lowest syneresis (8.5%) and better texture and sensory than the samples fermented by YO-MIX 465 and YF-L711. It manifested that the selected higher exopolysaccharide production starter SH-1 could be used as yogurt starter and reduce the amount of adding stabilizer, which can compare with the imported commercial starter culture.

Viability and Virulence of Entomopathogenic Nematodes Exposed to Ultraviolet Radiation.

PubMed

Shapiro-Ilan, David I; Hazir, Selcuk; Lete, Luis

2015-09-01

Entomopathogenic nematodes (EPNs) can be highly effective biocontrol agents, but their efficacy can be reduced due to exposure to environmental stress such as from ultraviolet (UV) radiation. Our objectives were to 1) compare UV tolerance among a broad array of EPN species, and 2) investigate the relationship between reduced nematode viability (after exposure to UV) and virulence. Nematodes exposed to a UV radiation (254 nm) for 10 or 20 min were assessed separately for viability (survival) and virulence to Galleria mellonella. We compared 9 different EPN species and 15 strains: Heterorhabditis bacteriophora (Baine, fl11, Oswego, and Vs strains), H. floridensis (332), H. georgiana (Kesha), H. indica (HOM1), H. megidis (UK211), Steinernema carpocapsae (All, Cxrd, DD136, and Sal strains), S. feltiae (SN), S. rarum (17C&E), and S. riobrave (355). In viability assessments, steinernematids, particularly strains of S. carpocapsae, generally exhibited superior UV tolerance compared with the heterorhabditids. However, some heterorhabditids tended to be more tolerant than others, e.g., H. megidis and H. bacteriophora (Baine) were most susceptible and H. bacteriophora (Vs) was the only heterorhabditid that did not exhibit a significant effect after 10 min of exposure. All heterorhabditids experienced reduced viability after 20 min exposure though several S. carpocapsae strains did not. In total, after 10 or 20 min exposure, the viability of seven nematode strains did not differ from their non-UV exposed controls. In virulence assays, steinernematids (particularly S. carpocapsae strains) also tended to exhibit higher UV tolerance. However, in contrast to the viability measurements, all nematodes experienced a reduction in virulence relative to their controls. Correlation analysis revealed that viability among nematode strains is not necessarily related to virulence. In conclusion, our results indicate that the impact of UV varies substantially among EPNs, and viability alone is not a sufficient measure for potential impact on biocontrol efficacy as other characters such as virulence may be severely affected even when viability remains high.

Photosynthetic conversion of CO2 to farnesyl diphosphate-derived phytochemicals (amorpha-4,11-diene and squalene) by engineered cyanobacteria.

PubMed

Choi, Sun Young; Lee, Hyun Jeong; Choi, Jaeyeon; Kim, Jiye; Sim, Sang Jun; Um, Youngsoon; Kim, Yunje; Lee, Taek Soon; Keasling, Jay D; Woo, Han Min

2016-01-01

Metabolic engineering of cyanobacteria has enabled photosynthetic conversion of CO2 to value-added chemicals as bio-solar cell factories. However, the production levels of isoprenoids in engineered cyanobacteria were quite low, compared to other microbial hosts. Therefore, modular optimization of multiple gene expressions for metabolic engineering of cyanobacteria is required for the production of farnesyl diphosphate-derived isoprenoids from CO2. Here, we engineered Synechococcus elongatus PCC 7942 with modular metabolic pathways consisting of the methylerythritol phosphate pathway enzymes and the amorphadiene synthase for production of amorpha-4,11-diene, resulting in significantly increased levels (23-fold) of amorpha-4,11-diene (19.8 mg/L) in the best strain relative to a parental strain. Replacing amorphadiene synthase with squalene synthase led to the synthesis of a high amount of squalene (4.98 mg/L/OD730). Overexpression of farnesyl diphosphate synthase is the most critical factor for the significant production, whereas overexpression of 1-deoxy-d-xylulose 5-phosphate reductase is detrimental to the cell growth and the production. Additionally, the cyanobacterial growth inhibition was alleviated by expressing a terpene synthase in S. elongatus PCC 7942 strain with the optimized MEP pathway only (SeHL33). This is the first demonstration of photosynthetic production of amorpha-4,11-diene from CO2 in cyanobacteria and production of squalene in S. elongatus PCC 7942. Our optimized modular OverMEP strain (SeHL33) with either co-expression of ADS or SQS demonstrated the highest production levels of amorpha-4,11-diene and squalene, which could expand the list of farnesyl diphosphate-derived isoprenoids from CO2 as bio-solar cell factories.

Evaluation of the use of various rat strains for immunogenic potency tests of Sabin-derived inactivated polio vaccines.

PubMed

Someya, Yuichi; Ami, Yasushi; Takai-Todaka, Reiko; Fujimoto, Akira; Haga, Kei; Murakami, Kosuke; Fujii, Yoshiki; Shirato, Haruko; Oka, Tomoichiro; Shimoike, Takashi; Katayama, Kazuhiko; Wakita, Takaji

2018-03-01

Slc:Wistar rats have been the only strain used in Japan for purpose of evaluating a national reference vaccine for the Sabin-derived inactivated polio vaccine (sIPV) and the immunogenicity of sIPV-containing products. However, following the discovery that the Slc:Wistar strain was genetically related to the Fischer 344 strain, other "real" Wistar strains, such as Crlj:WI, that are available worldwide were tested in terms of their usefulness in evaluating the immunogenicity of the past and current lots of a national reference vaccine. The response of the Crlj:WI rats against the serotype 1 of sIPV was comparable to that of the Slc:Wistar rats, while the Crlj:WI rats exhibited a higher level of response against the serotypes 2 and 3. The immunogenic potency units of a national reference vaccine determined using the Slc:Wistar rats were reproduced on tests using the Crlj:WI rats. These results indicate that a titer of the neutralizing antibody obtained in response to a given dose of sIPV cannot be directly compared between these two rat strains, but that, more importantly, the potency units are almost equivalent for the two rat strains. Copyright © 2018 International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.

Cross-reactions between alpha-streptococci and Omniserum, a polyvalent pneumococcal serum, demonstrated by direct immunofluorescence, immunoelectroosmophoresis, and latex agglutination.

PubMed Central

Holmberg, H; Danielsson, D; Hardie, J; Krook, A; Whiley, R

1985-01-01

In recent years several groups have used serological methods to demonstrate pneumococcal capsular antigens in sputum. In the present study 123 strains of alpha-hemolytic streptococci (including 97 strains from sputum or pharyngeal specimens) were tested for cross-reactions with a polyvalent antipneumococcal serum (Omniserum). Representatives of the following species were included: Streptococcus bovis, S. equinus, S. intermedius, S. lactis, S. milleri, S. mitis, S. mutans, S. sobrinus, S. salivarius, S. sanguis, S. suis, and Aerococcus viridans. Serological reactions were detected by direct immunofluorescence, immunoelectroosmophoresis, and latex agglutination. Fifteen (12%) of the strains gave positive reactions by all three methods. Positive reactions were also observed with another 32 strains (26%) with two of the methods, whereas 37 strains (30%) gave positive reactions by just one technique. Altogether 84 (68%) strains gave positive reactions with one or more of the methods. Latex agglutination gave positive reactions with 26 (21%) strains compared with 57 (46%) in immunofluorescence and 63 (51%) in immunoelectroosmophoresis. Absorption of the antiserum with one alpha-hemolytic strain reduced but did not entirely eliminate the cross-reactions with five tested strains. These findings indicate a potential risk of cross-reactions with polyvalent antipneumococcal serum in tests carried out on sputa or other specimens which may be contaminated with alpha-hemolytic streptococci. PMID:3889046

Deaths from bacterial pneumonia during 1918-19 influenza pandemic.

PubMed

Brundage, John F; Shanks, G Dennis

2008-08-01

Deaths during the 1918-19 influenza pandemic have been attributed to a hypervirulent influenza strain. Hence, preparations for the next pandemic focus almost exclusively on vaccine prevention and antiviral treatment for infections with a novel influenza strain. However, we hypothesize that infections with the pandemic strain generally caused self-limited (rarely fatal) illnesses that enabled colonizing strains of bacteria to produce highly lethal pneumonias. This sequential-infection hypothesis is consistent with characteristics of the 1918-19 pandemic, contemporaneous expert opinion, and current knowledge regarding the pathophysiologic effects of influenza viruses and their interactions with respiratory bacteria. This hypothesis suggests opportunities for prevention and treatment during the next pandemic (e.g., with bacterial vaccines and antimicrobial drugs), particularly if a pandemic strain-specific vaccine is unavailable or inaccessible to isolated, crowded, or medically underserved populations.

Effect of a personal ambient ventilation system on physiological strain during heat stress wearing a ballistic vest.

PubMed

Hadid, A; Yanovich, R; Erlich, T; Khomenok, G; Moran, D S

2008-09-01

The present study was conducted in order to evaluate whether physiological strain is alleviated by a new personal cooling system (CS) consisting of a layered vest and integrated blower that generate a flow of air. Twelve male volunteers were exposed to climatic conditions of 40 degrees C, 40%RH (40/40), and 35 degrees C, 60%RH (35/60) during a 115 min exercise routine, followed by 70 min resting recovery, while wearing a battle dress uniform (BDU) and a ballistic vest, with (COOL) or without (NOCOOL) CS. The CS was able to attenuate the physiological strain levels during exercise, when compared to identical exposures without the CS. Temperature elevation, (DeltaT (re)) after 100 min of exercise, was lower by 0.26 +/- 0.20 and 0.34 +/- 0.21 degrees C in 40/40 and 35/60, respectively, (p < 0.05). Mean skin temperature (T(sk)) was lower by 0.9 +/- 0.4 and 0.6 +/- 0.5 degrees C for 40/40 and 35/60, respectively. Heart rate (HR) was not significantly different for COOL versus NOCOOL for 40/40. At 35/60, HR was lower by 10 beats per min (bpm) (p < 0.05). Physiological strain index (PSI) was 9 and 21% lower for the 40/40 and 35/60, respectively, for COOL versus NOCOOL (p < 0.05). Heat storage (S) rates were 19 and 24% lower and sweat rates were 21 and 25% lower for the 40/40 and 35/60, respectively, for COOL versus NOCOOL (p < 0.05). However, the CS was not effective in alleviating physiological strain during resting recovery with no difference in T (re) cooling rate, S, or HR drop rate between groups over resting recovery periods. The CS tested in this study was found to be an effective tool for lowering physiological strain while exercising but not during resting recovery. Therefore, the CS should be further developed in order to achieve greater attenuation of the thermal strain during exercise and improve effectiveness during rest. Overall, it has the potential to be useful for both military and sports personnel.

Orientation Dependence of Functional Properties in Heterophase Single Crystals of the Ti36.5Ni51.0Hf12.5 and Ti48.5Ni51.5 Alloys

NASA Astrophysics Data System (ADS)

Panchenko, E. Yu.; Chumlyakov, Yu. I.; Surikov, N. Yu.; Tagiltsev, A. I.; Vetoshkina, N. G.; Osipovich, K. S.; Maier, H.; Sehitoglu, H.

2016-03-01

The features of orientation dependence of stress-induced thermoelastic B2-( R)- B19'-martensitic transformations in single crystals of the Ti48.5Ni51.5 and Ni51.0Ti36.5Hf12.5 (at.%) alloys, which contain disperse particles of the Ti3Ni4 and H-phase, respectively, are revealed along with those of their shape-memory effects (SME) and superelasticity (SE). It is experimentally demonstrated that irrespective of the crystal structure of disperse particles measuring more than 100 nm, for their volume fraction f > 16% there is a weaker orientation dependence of the reversible strain in the cases of manifestation of SME and SE. In the orientations of Class I, wherein martensitic detwinning introduces a considerable contribution into transformation strain, the values of SME |ɛ SME | and SE |ɛ SE | decrease by over a factor of two compared to the theoretical lattice strain value |ɛ tr0 | for a B2- B19'-transformation and the experimental values of reversible strain for quenched TiNi crystals. In the orientations of Class 2, wherein detwinning of the martensite is suppressed as is the case in quenched single-phase single crystals, the reversible strain is maintained close to its theoretical value |ɛ tr0 |. Micromechanical models of interaction between the martensite and the disperse particles are proposed, which account for the weaker orientation dependence of |ɛ SME | and |ɛ SE | due to suppression of detwinning of the B19'-martensite crystals by the particles and a transition from a single-variant evolution of the stress-induced martensitic transformations to a multiple-variant evolution of transformations in the cases of increased size of the particles and their larger volume fractions.

Genome Sequencing of Sulfolobus sp. A20 from Costa Rica and Comparative Analyses of the Putative Pathways of Carbon, Nitrogen, and Sulfur Metabolism in Various Sulfolobus Strains.

PubMed

Dai, Xin; Wang, Haina; Zhang, Zhenfeng; Li, Kuan; Zhang, Xiaoling; Mora-López, Marielos; Jiang, Chengying; Liu, Chang; Wang, Li; Zhu, Yaxin; Hernández-Ascencio, Walter; Dong, Zhiyang; Huang, Li

2016-01-01

The genome of Sulfolobus sp. A20 isolated from a hot spring in Costa Rica was sequenced. This circular genome of the strain is 2,688,317 bp in size and 34.8% in G+C content, and contains 2591 open reading frames (ORFs). Strain A20 shares ~95.6% identity at the 16S rRNA gene sequence level and <30% DNA-DNA hybridization (DDH) values with the most closely related known Sulfolobus species (i.e., Sulfolobus islandicus and Sulfolobus solfataricus ), suggesting that it represents a novel Sulfolobus species. Comparison of the genome of strain A20 with those of the type strains of S. solfataricus, Sulfolobus acidocaldarius, S. islandicus , and Sulfolobus tokodaii , which were isolated from geographically separated areas, identified 1801 genes conserved among all Sulfolobus species analyzed (core genes). Comparative genome analyses show that central carbon metabolism in Sulfolobus is highly conserved, and enzymes involved in the Entner-Doudoroff pathway, the tricarboxylic acid cycle and the CO 2 fixation pathways are predominantly encoded by the core genes. All Sulfolobus species encode genes required for the conversion of ammonium into glutamate/glutamine. Some Sulfolobus strains have gained the ability to utilize additional nitrogen source such as nitrate (i.e., S. islandicus strain REY15A, LAL14/1, M14.25, and M16.27) or urea (i.e., S. islandicus HEV10/4, S. tokodaii strain7, and S. metallicus DSM 6482). The strategies for sulfur metabolism are most diverse and least understood. S. tokodaii encodes sulfur oxygenase/reductase (SOR), whereas both S. islandicus and S. solfataricus contain genes for sulfur reductase (SRE). However, neither SOR nor SRE genes exist in the genome of strain A20, raising the possibility that an unknown pathway for the utilization of elemental sulfur may be present in the strain. The ability of Sulfolobus to utilize nitrate or sulfur is encoded by a gene cluster flanked by IS elements or their remnants. These clusters appear to have become fixed at a specific genomic site in some strains and lost in other strains during the course of evolution. The versatility in nitrogen and sulfur metabolism may represent adaptation of Sulfolobus to thriving in different habitats.

Genome Sequencing of Sulfolobus sp. A20 from Costa Rica and Comparative Analyses of the Putative Pathways of Carbon, Nitrogen, and Sulfur Metabolism in Various Sulfolobus Strains

PubMed Central

Dai, Xin; Wang, Haina; Zhang, Zhenfeng; Li, Kuan; Zhang, Xiaoling; Mora-López, Marielos; Jiang, Chengying; Liu, Chang; Wang, Li; Zhu, Yaxin; Hernández-Ascencio, Walter; Dong, Zhiyang; Huang, Li

2016-01-01

The genome of Sulfolobus sp. A20 isolated from a hot spring in Costa Rica was sequenced. This circular genome of the strain is 2,688,317 bp in size and 34.8% in G+C content, and contains 2591 open reading frames (ORFs). Strain A20 shares ~95.6% identity at the 16S rRNA gene sequence level and <30% DNA-DNA hybridization (DDH) values with the most closely related known Sulfolobus species (i.e., Sulfolobus islandicus and Sulfolobus solfataricus), suggesting that it represents a novel Sulfolobus species. Comparison of the genome of strain A20 with those of the type strains of S. solfataricus, Sulfolobus acidocaldarius, S. islandicus, and Sulfolobus tokodaii, which were isolated from geographically separated areas, identified 1801 genes conserved among all Sulfolobus species analyzed (core genes). Comparative genome analyses show that central carbon metabolism in Sulfolobus is highly conserved, and enzymes involved in the Entner-Doudoroff pathway, the tricarboxylic acid cycle and the CO2 fixation pathways are predominantly encoded by the core genes. All Sulfolobus species encode genes required for the conversion of ammonium into glutamate/glutamine. Some Sulfolobus strains have gained the ability to utilize additional nitrogen source such as nitrate (i.e., S. islandicus strain REY15A, LAL14/1, M14.25, and M16.27) or urea (i.e., S. islandicus HEV10/4, S. tokodaii strain7, and S. metallicus DSM 6482). The strategies for sulfur metabolism are most diverse and least understood. S. tokodaii encodes sulfur oxygenase/reductase (SOR), whereas both S. islandicus and S. solfataricus contain genes for sulfur reductase (SRE). However, neither SOR nor SRE genes exist in the genome of strain A20, raising the possibility that an unknown pathway for the utilization of elemental sulfur may be present in the strain. The ability of Sulfolobus to utilize nitrate or sulfur is encoded by a gene cluster flanked by IS elements or their remnants. These clusters appear to have become fixed at a specific genomic site in some strains and lost in other strains during the course of evolution. The versatility in nitrogen and sulfur metabolism may represent adaptation of Sulfolobus to thriving in different habitats. PMID:27965637

[Phylogenetic and diversity analysis of Acidithiobacillus spp. based on 16S rRNA and RubisCO genes homologues].

PubMed

Liu, Minrui; Lin, Pengwu; Qi, Xing'e; Ni, Yongqing

2016-04-14

The purpose of the study was to reveal geographic region-related Acidithiobacillus spp. distribution and allopatric speciation. Phylogenetic and diversity analysis was done to expand our knowledge on microbial phylogeography, diversity-maintaining mechanisms and molecular biogeography. We amplified 16S rRNA gene and RubisCO genes to construct corresponding phylogenetic trees based on the sequence homology and analyzed genetic diversity of Acidithiobacillus spp.. Thirty-five strains were isolated from three different regions in China (Yunnan, Hubei, Xinjiang). The whole isolates were classified into five groups. Four strains were identified as A. ferrivorans, six as A. ferridurans, YNTR4-15 Leptspirillum ferrooxidans and HBDY3-31 as Leptospirillum ferrodiazotrophum. The remaining strains were identified as A. ferrooxidans. Analysis of cbbL and cbbM genes sequences of representative 26 strains indicated that cbbL gene of 19 were two copies (cbbL1 and cbbL2) and 7 possessed only cbbL1. cbbM gene was single copy. In nucleotide-based trees, cbbL1 gene sequences of strains were separated into three sequence types, and the cbbL2 was similar to cbbL1 with three types. Codon bias of RubisCO genes was not obvious in Acidithiobacillus spp.. Strains isolated from three different regions in China indicated a great genetic diversity in Acidithiobacillus spp. and their 16S rRNA/RubisCO genes sequence was of significant difference. Phylogenetic tree based on 16S rRNA genes and RubisCO genes was different in Acidithiobacillus spp..

[Characteristics of drug resistance and molecular typing research for Salmonella Enteritidis isolated in Henan province from 2011 to 2013].

PubMed

Zhao, Jiayong; Zhang, Yukai; Xie, Zhiqiang; Pan, Jingjing; Su, Jia; Mu, Yujiao; Huang, Xueyong; Zhang, Baifan; Xia, Shengli

2016-03-01

To investigate the antimicrobial resistance status and pulsed field gel electrophoresis (PFGE) patterns of Salmonella Enteritidis (S.Enteritidis) strains in Henan province. S. Enteritidis strains were isolated from seven sentinel hospitals from March 2011 to December 2013. According to molecular typing and Salmonella (Kirby-Bauer, K-B) drug susceptibility testing method published by the international PulseNet bacterial infectious disease monitoring network and USA Clinical and Laboratory Standards Institute (CLSI), we analyzed drug sensitivity of 8 kinds antibiotics and PFGE molecule characteristics of 120 S. Enteritidis isolates from seven sentinel hospitals. Among 120 strains of S. Enteritidis, 77 were isolated from male patients, 43 from female patients. A total of 78 strains S. Enteritidis were isolated from young children ranged from 0 to 5 years old (65.0%), including 57 strains isolated from 6 months to 2 years old (47.5%). The isolated time mainly centralized on May to October of the year, 11 strains isolated in March-April (9.2%), 48 were in May-July (40.0%),54 in August-October (45.0%), 7 in other months, with a typical summer seasonal characteristics. The resistance rate of 120 strains S. Enteritidis to ampicillin was 50.0% (n=60); to ceftazidime was 14.2% (n=17), to cefotaxime was 18.3% (n=22); to cefepime was 5.8% (n=7); to nalidixic acid was 61.7% (n=74); to ciprofloxacin was 8.3% (n=10), to norfloxacin was 5.8% (n=7); to gentamicin was 42.5% (n=51); to streptomycin was 21.7% (n=26); to chloramphenicol was 30.0% (n=36); resistance to methicillin benzyl ammonium was 11.7% (n=14), compound sulfamethoxazole resistance rate was 71.7% (n=86); the tetracycline resistant rate was 47.5% (n=57). All 120 strains of S. Enteritidis had different levels of resistance to 8 kinds of antibiotics, all strains were multidrug resistant strains, 28 isolates were resistant to 3-4 kinds of antibiotics (23.3%), 38 isolates were resistant to 5-6 kinds of antibiotics (31.7%), 39 isolates were resistant to 7-8 kinds of antibiotics (32.5%). All 120 strains of S. Enteritidis were divided into 44 molecular patterns by digestion with XbaI and pulsed field gel electrophoresis. each pattern contained 1-35 strains with similarity ranged from 54.3%-100%. EN14 and EN19 were the main PFGE types, including 35 and 29 strains respectively. The status of drug resistance of clinical isolates of Salmonella in Henan province was rather serious, PFGE patterns showed advantages and partial strain's corresponding resistant spectrum have certain relevance and the same aggregation relationship.

Streptomyces humi sp. nov., an actinobacterium isolated from soil of a mangrove forest.

PubMed

Zainal, Nurullhudda; Ser, Hooi-Leng; Yin, Wai-Fong; Tee, Kok-Keng; Lee, Learn-Han; Chan, Kok-Gan

2016-03-01

A novel Streptomyces strain, MUSC 119(T), was isolated from a soil collected from a mangrove forest. Cells of MUSC 119(T) stained Gram-positive and formed light brownish grey aerial mycelium and grayish yellowish brown substrate mycelium on ISP 2 medium. A polyphasic approach was used to determine the taxonomic status of strain MUSC 119(T), which shows a range of phylogenetic and chemotaxonomic properties consistent with those of the genus Streptomyces. The cell wall peptidoglycan consisted of LL-diaminopimelic acid. The predominant menaquinones were identified as MK-9(H8), MK-9(H6) and MK-9(H4). The polar lipid profile consisted of phosphatidylinositol, phosphatidylethanolamine, glycolipids, diphosphatidylglycerol and four phospholipids. The predominant cellular fatty acids were anteiso-C15:0, iso-C16:0, and anteiso-C17:0. The cell wall sugars were glucose, mannose, ribose and rhamnose. The phylogenetic analysis based on 16S rRNA gene sequence similarity showed that strain MUSC119(T) to be closely related to Streptomyces rhizophilus JR-41(T) (99.0 % sequence similarity), S. panaciradicis 1MR-8(T) (98.9 %), S. gramineus JR-43(T) (98.8 %) and S. graminisoli JR-19(T) (98.7 %). These results suggest that MUSC 119(T) should be placed within the genus Streptomyces. DNA-DNA relatedness values between MUSC 119(T) to closely related strains ranged from 14.5 ± 1.3 to 27.5 ± 0.7 %. The G+C content was determined to be 72.6 mol %. The polyphasic study of MUSC 119(T) showed that this strain represents a novel species, for which the name Streptomyces humi sp. nov. is proposed. The type strain of S. humi is MUSC 119(T) (=DSM 42174(T) = MCCC 1K00505(T)).

The Salmonella dublin virulence plasmid mediates systemic but not enteric phases of salmonellosis in cattle.

PubMed Central

Wallis, T S; Paulin, S M; Plested, J S; Watson, P R; Jones, P W

1995-01-01

Plasmid-bearing and plasmid-free isolates and a plasmid-cured strain of Salmonella dublin were compared for virulence in calves. The plasmid-bearing strains were highly virulent, causing severe enteric and systemic disease with high mortality. In contrast, the plasmid-free strains caused diarrhea but only low mortality. The infection kinetics of a wild-type and a derivative plasmid-cured strain were compared. Both strains were isolated in high numbers from intestinal sites at 3 and 6 days after oral challenge and were isolated at comparable frequencies from systemic sites at 3 days, but not at 6 days, when the wild-type strain was predominant. The strains were equally invasive in intestinal epithelia with and without Peyer's patch and elicited comparable secretory and inflammatory responses and intestinal pathology in ligated ileal loops. The effect of the virulence plasmid on growth kinetics and on the outer membrane protein profile was assessed in an in vivo growth chamber. The virulence plasmid did not influence either extracellular growth or the expression of major outer membrane proteins. These observations demonstrate that the virulence plasmid is not involved in either the enteric phase of infection or the systemic dissemination of S. dublin but probably mediates the persistence of S. dublin at systemic sites. PMID:7790094

Differences in the population structure of invasive Streptococcus suis strains isolated from pigs and from humans in The Netherlands.

PubMed

Schultsz, Constance; Jansen, Ewout; Keijzers, Wendy; Rothkamp, Anja; Duim, Birgitta; Wagenaar, Jaap A; van der Ende, Arie

2012-01-01

Streptococcus suis serotype 2 is the main cause of zoonotic S. suis infection despite the fact that other serotypes are frequently isolated from diseased pigs. Studies comparing concurrent invasive human and pig isolates from a single geographical location are lacking. We compared the population structures of invasive S. suis strains isolated between 1986 and 2008 from human patients (N = 24) and from pigs with invasive disease (N = 124) in The Netherlands by serotyping and multi locus sequence typing (MLST). Fifty-six percent of pig isolates were of serotype 9 belonging to 15 clonal complexes (CCs) or singleton sequence types (ST). In contrast, all human isolates were of serotype 2 and belonged to two non-overlapping clonal complexes CC1 (58%) and CC20 (42%). The proportion of serotype 2 isolates among S. suis strains isolated from humans was significantly higher than among strains isolated from pigs (24/24 vs. 29/124; P<0.0001). This difference remained significant when only strains within CC1 and CC20 were considered (24/24 vs. 27/37,P = 0.004). The Simpson diversity index of the S. suis population isolated from humans (0.598) was smaller than of the population isolated from pigs (0.765, P = 0.05) indicating that the S. suis population isolated from infected pigs was more diverse than the S. suis population isolated from human patients. S. suis serotype 2 strains of CC20 were all negative in a PCR for detection of genes encoding extracellular protein factor (EF) variants. These data indicate that the polysaccharide capsule is an important correlate of human S. suis infection, irrespective of the ST and EF encoding gene type of S. suis strains.

Discovery and Characterization of Human-Urine Utilization by Asymptomatic-Bacteriuria-Causing Streptococcus agalactiae.

PubMed

Ipe, Deepak S; Ben Zakour, Nouri L; Sullivan, Matthew J; Beatson, Scott A; Ulett, Kimberly B; Benjamin, William H; Davies, Mark R; Dando, Samantha J; King, Nathan P; Cripps, Allan W; Schembri, Mark A; Dougan, Gordon; Ulett, Glen C

2016-01-01

Streptococcus agalactiae causes both symptomatic cystitis and asymptomatic bacteriuria (ABU); however, growth characteristics of S. agalactiae in human urine have not previously been reported. Here, we describe a phenotype of robust growth in human urine observed in ABU-causing S. agalactiae (ABSA) that was not seen among uropathogenic S. agalactiae (UPSA) strains isolated from patients with acute cystitis. In direct competition assays using pooled human urine inoculated with equal numbers of a prototype ABSA strain, designated ABSA 1014, and any one of several UPSA strains, measurement of the percentage of each strain recovered over time showed a markedly superior fitness of ABSA 1014 for urine growth. Comparative phenotype profiling of ABSA 1014 and UPSA strain 807, isolated from a patient with acute cystitis, using metabolic arrays of >2,500 substrates and conditions revealed unique and specific l-malic acid catabolism in ABSA 1014 that was absent in UPSA 807. Whole-genome sequencing also revealed divergence in malic enzyme-encoding genes between the strains predicted to impact the activity of the malate metabolic pathway. Comparative growth assays in urine comparing wild-type ABSA and gene-deficient mutants that were functionally inactivated for the malic enzyme metabolic pathway by targeted disruption of the maeE or maeK gene in ABSA demonstrated attenuated growth of the mutants in normal human urine as well as synthetic human urine containing malic acid. We conclude that some S. agalactiae strains can grow in human urine, and this relates in part to malic acid metabolism, which may affect the persistence or progression of S. agalactiae ABU. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Pathogenesis comparison between the United States porcine epidemic diarrhoea virus prototype and S-INDEL-variant strains in conventional neonatal piglets.

PubMed

Chen, Qi; Gauger, Phillip C; Stafne, Molly R; Thomas, Joseph T; Madson, Darin M; Huang, Haiyan; Zheng, Ying; Li, Ganwu; Zhang, Jianqiang

2016-05-01

At least two genetically different porcine epidemic diarrhoea virus (PEDV) strains have been identified in the USA: US PEDV prototype and S-INDEL-variant strains. The objective of this study was to compare the pathogenicity differences of the US PEDV prototype and S-INDEL-variant strains in conventional neonatal piglets under experimental infections. Fifty PEDV-negative 5-day-old pigs were divided into five groups of ten pigs each and were inoculated orogastrically with three US PEDV prototype isolates (IN19338/2013, NC35140/2013 and NC49469/2013), an S-INDEL-variant isolate (IL20697/2014), and virus-negative culture medium, respectively, with virus titres of 104 TCID50 ml- 1, 10 ml per pig. All three PEDV prototype isolates tested in this study, regardless of their phylogenetic clades, had similar pathogenicity and caused severe enteric disease in 5-day-old pigs as evidenced by clinical signs, faecal virus shedding, and gross and histopathological lesions. Compared with pigs inoculated with the three US PEDV prototype isolates, pigs inoculated with the S-INDEL-variant isolate had significantly diminished clinical signs, virus shedding in faeces, gross lesions in small intestines, caeca and colons, histopathological lesions in small intestines, and immunohistochemistry staining in ileum. However, the US PEDV prototype and the S-INDEL-variant strains induced similar viraemia levels in inoculated pigs. Whole genome sequences of the PEDV prototype and S-INDEL-variant strains were determined, but the molecular basis of virulence differences between these PEDV strains remains to be elucidated using a reverse genetics approach.

Classification of Culturable Bifidobacterial Population from Colonic Samples of Wild Pigs (Sus scrofa) Based on Three Molecular Genetic Methods.

PubMed

Pechar, Radko; Killer, Jiří; Mekadim, Chahrazed; Geigerová, Martina; Rada, Vojtěch

2017-11-01

Occurrence of bifidobacteria, known as health-promoting probiotic microorganisms, in the digestive tract of wild pigs (Sus scrofa) has not been examined yet. One hundred forty-nine fructose-6-phosphate phosphoketolase positive bacterial strains were isolated from colonic content of twenty-two individuals of wild pigs originated from four localities in the Czechia. Based on PCR-DGGE technique targeting the variable V3 region of the 16S rRNA genes, strains were initially differentiated into four groups represented by: (i) probably a new Bifidobacterium species (89 strains), (ii) B. boum/B. thermophilum/B. thermacidophilum subsp. porcinum/B. thermacidophilum subsp. thermacidophilum (sub)species (49 strains), (iii) Pseudoscardovia suis (7 strains), and (iv) B. pseudolongum subsp. globosum/B. pseudolongum subsp. pseudolongum (4 strains), respectively. Given the fact that DGGE technique did not allow to differentiate the representatives of thermophilic bifidobacteria and B. pseudolongum subspecies, strains were further classified by the 16S rRNA and thrS gene sequences. Primers targeting the variable regions of the latter gene were designed to be applicable in identification and phylogeny of Bifidobacteriaceae family. The 16S rRNA-derived phylogenetic study classified members of the first group into five subgroups in a separated cluster of thermophilic bifidobacteria. Comparable results were obtained by the thrS-derived phylogenetic analysis. Remarkably, variability among thrS sequences was higher compared with 16S rRNA gene sequences. Overall, molecular genetic techniques application allowed to identify a new Bifidobacterium phylotype which is predominant in the digestive tract of examined wild pigs.

The ability of four strains of Streptococcus uberis to induce clinical mastitis after intramammary inoculation in lactating cows.

PubMed

Notcovich, S; deNicolo, G; Williamson, N B; Grinberg, A; Lopez-Villalobos, N; Petrovski, K R

2016-07-01

To compare the ability of four strains of Streptococcus uberis at two doses to induce clinical mastitis in lactating dairy cows after intramammary inoculation in order to evaluate their usefulness for future experimental infection models. Four field strains of S. uberis (26LB, S418, and S523 and SR115) were obtained from cows with clinical mastitis in the Wairarapa and Waikato regions of New Zealand. Twenty-four crossbred lactating cows, with no history of mastitis and absence of major pathogens following culture of milk samples, were randomly allocated to four groups (one per strain) of six cows. Each cow was infused (Day 0) in one quarter with approximately 10(4) cfu and in the contralateral quarter with approximately 10(6) cfu of the same strain. The other two quarters remained unchallenged. All four quarters were then inspected for signs of clinical mastitis, by palpation and observation of the foremilk, twice daily from Days 0-9, and composite milk samples were collected from Days 0-8 for analysis of somatic cell counts (SCC). Quarters were treated with penicillin when clinical mastitis was observed. Duplicate milk samples were collected and cultured on presentation of each clinical case and on Day 4 from challenged quarters with no clinical signs. Clinical mastitis was diagnosed in 26/48 (54%) challenged quarters. Challenge with strain S418 resulted in more cases of mastitis (12/12 quarters) than strains SR115 (7/12), 26LB (6/12) or S523 (1/12), and the mean interval from challenge to first diagnosis of mastitis was shorter for S418 than the other strains (p<0.001). The proportion of quarters from which S. uberis could be isolated after challenge was less for strain 26LB (1/6) than SR115 (6/7) (p<0.05), and SCC following challenge was lower for strain S523 than the other strains (p<0.05). There were significant differences between the strains in the proportion of quarters developing clinical mastitis, the interval to mastitis onset, SCC following challenge and the proportion of clinical cases from which S. uberis could be isolated. These results illustrate the difference in the ability of S. uberis strains to cause mastitis and the severity of the infections caused. Experimental challenge models can be used to compare infectivity and pathogenicity of different strains of mastitis-causing bacteria, the efficacy of pharmaceutical products and host-responses in a cost-effective manner.

In vitro effectiveness of triterpenoids and their synergistic effect with antibiotics against Staphylococcus aureus strains.

PubMed

Hamza, Muhammad; Nadir, Maha; Mehmood, Nadir; Farooq, Adeel

2016-01-01

The aim of this study is to evaluate the effect of four triterpenoids such as oleanolic acid, ursolic acid, cycloastragenol, and beta-boswellic acid alone and in combination with antibiotics against Staphylococcus aureus strains. Sixteen clinical strains of S. aureus from infected wounds were isolated. Eight were methicillin-sensitive S. aureus (MSSA), and the other eight were methicillin-resistant S. aureus (MRSA). The activity was also seen in reference S. aureus American Type Culture Collection ™ strains. The activity of all the triterpenoids and antibiotics against S. aureus was evaluated by broth microdilution method. The effectiveness was judged by comparing the minimum inhibitory concentrations (MICs) of the compounds with antibiotics. The combination of antibiotics with compounds was evaluated by their fractional inhibitory concentrations (FIC). Against both clinical and reference MSSA strains, none of the compounds exhibited comparable activity to antibiotics vancomycin or cefradine except for ursolic acid (MIC 7.8 μg/ml). Against MRSA, all compounds (MIC 16-128 μg/ml) showed lesser activity than vancomycin (MIC 5.8 μg/ml). Among triterpenoid-antibiotic combinations, the most effective were ursolic acid and vancomycin against clinical strain MSSA (FIC S 0.17). However, overall, different combinations between triterpenoids and antibiotics showed 95%-46% ( P < 0.05) reduction in MICs of antibiotics compared to when antibiotics were used alone. Cefradine, a drug not suitable for treating MRSA (MIC = 45 μg/ml), showed a remarkable decrease in its MIC (87% P< 0.01) when it was used in combination with oleanolic acid or ursolic acid in both clinical and reference strains. The tested triterpenoids are relatively weaker than antibiotics. However, when used in combination with antibiotics, they showed remarkable synergistic effect and thus can help in prolonging the viability of these antibiotics against S. aureus infections. Furthermore, reduction in MIC of cefradine with oleanolic acid indicates their potential use against MRSA.

In Vitro Activity of the Novel Lactone Ketolide Nafithromycin (WCK 4873) against Contemporary Clinical Bacteria from a Global Surveillance Program.

PubMed

Flamm, R K; Rhomberg, P R; Sader, H S

2017-12-01

Nafithromycin (WCK 4873), a novel antimicrobial agent of the lactone ketolide class, is currently in phase 2 development for treatment of community-acquired bacterial pneumonia (CABP). A total of 4,739 nonduplicate isolates were selected from a 2014 global surveillance program at medical institutions located in 43 countries within the United States, Europe, Latin America, and the Asia-Pacific region. Nafithromycin and comparator agents were used for susceptibility testing by reference broth microdilution methods. Nafithromycin was active against Staphylococcus aureus (MIC 50/90 , 0.06/>2 μg/ml), including erythromycin-resistant strains exhibiting an inducible clindamycin resistance phenotype (MIC 50/90 , 0.06/0.06 μg/ml) and telithromycin-susceptible strains (MIC 50/90 , 0.06/0.06 μg/ml), but it exhibited limited activity against most telithromycin-resistant and clindamycin-resistant isolates that were constitutively resistant to macrolides (MIC 50/90 , >2/>2 μg/ml). Nafithromycin was very active (MIC 50/90 , 0.015/0.06 μg/ml) against 1,911 Streptococcus pneumoniae strains, inhibiting all strains, with MIC values of ≤0.25 μg/ml. Telithromycin susceptibility was 99.9% for Streptococcus pneumoniae strains, and nafithromycin was up to 8-fold more potent than telithromycin. Overall, 37.9% of S. pneumoniae strains were resistant to erythromycin, and 19.7% were resistant to clindamycin. Nafithromycin was highly active against 606 Streptococcus pyogenes strains (MIC 50/90 , 0.015/0.015 μg/ml), inhibiting 100.0% of isolates at ≤0.5 μg/ml, and MIC 50/90 values (0.015/0.015 to 0.03 μg/ml) were similar for the 4 geographic regions. Nafithromycin and telithromycin demonstrated comparable in vitro activities against 1,002 Haemophilus influenzae isolates and 504 Moraxella catarrhalis isolates. Overall, nafithromycin showed potent in vitro activity against a broad range of contemporary (2014) global pathogens. These results support the continued clinical development of nafithromycin for treatment of CABP. Copyright © 2017 American Society for Microbiology.

Genome shuffling of Saccharomyces cerevisiae for enhanced glutathione yield and relative gene expression analysis using fluorescent quantitation reverse transcription polymerase chain reaction.

PubMed

Yin, Hua; Ma, Yanlin; Deng, Yang; Xu, Zhenbo; Liu, Junyan; Zhao, Junfeng; Dong, Jianjun; Yu, Junhong; Chang, Zongming

2016-08-01

Genome shuffling is an efficient and promising approach for the rapid improvement of microbial phenotypes. In this study, genome shuffling was applied to enhance the yield of glutathione produced by Saccharomyces cerevisiae YS86. Six isolates with subtle improvements in glutathione yield were obtained from populations generated by ultraviolet (UV) irradiation and nitrosoguanidine (NTG) mutagenesis. These yeast strains were then subjected to recursive pool-wise protoplast fusion. A strain library that was likely to yield positive colonies was created by fusing the lethal protoplasts obtained from both UV irradiation and heat treatments. After two rounds of genome shuffling, a high-yield recombinant YSF2-19 strain that exhibited 3.2- and 3.3-fold increases in glutathione production in shake flask and fermenter respectively was obtained. Comparative analysis of synthetase gene expression was conducted between the initial and shuffled strains using FQ (fluorescent quantitation) RT-PCR (reverse transcription polymerase chain reaction). Delta CT (threshold cycle) relative quantitation analysis revealed that glutathione synthetase gene (GSH-I) expression at the transcriptional level in the YSF2-19 strain was 9.9-fold greater than in the initial YS86. The shuffled yeast strain has a potential application in brewing, other food, and pharmaceutical industries. Simultaneously, the analysis of improved phenotypes will provide more valuable data for inverse metabolic engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

Potential of New Isolates of Dunaliella Salina for Natural β-Carotene Production.

PubMed

Xu, Yanan; Ibrahim, Iskander M; Wosu, Chiziezi I; Ben-Amotz, Ami; Harvey, Patricia J

2018-02-01

The halotolerant microalga Dunaliella salina has been widely studied for natural β-carotene production. This work shows biochemical characterization of three newly isolated Dunaliella salina strains, DF15, DF17, and DF40, compared with D. salina CCAP 19/30 and D. salina UTEX 2538 (also known as D. bardawil ). Although all three new strains have been genetically characterized as Dunaliella salina strains, their ability to accumulate carotenoids and their capacity for photoprotection against high light stress are different. DF15 and UTEX 2538 reveal great potential for producing a large amount of β-carotene and maintained a high rate of photosynthesis under light of high intensity; however, DF17, DF40, and CCAP 19/30 showed increasing photoinhibition with increasing light intensity, and reduced contents of carotenoids, in particular β-carotene, suggesting that the capacity of photoprotection is dependent on the cellular content of carotenoids, in particular β-carotene. Strong positive correlations were found between the cellular content of all-trans β-carotene, 9- cis β-carotene, all-trans α-carotene and zeaxanthin but not lutein in the D. salina strains. Lutein was strongly correlated with respiration in photosynthetic cells and strongly related to photosynthesis, chlorophyll and respiration, suggesting an important and not hitherto identified role for lutein in coordinated control of the cellular functions of photosynthesis and respiration in response to changes in light conditions, which is broadly conserved in Dunaliella strains. Statistical analysis based on biochemical data revealed a different grouping strategy from the genetic classification of the strains. The significance of these data for strain selection for commercial carotenoid production is discussed.

16S-ARDRA and MALDI-TOF mass spectrometry as tools for identification of Lactobacillus bacteria isolated from poultry.

PubMed

Dec, Marta; Puchalski, Andrzej; Urban-Chmiel, Renata; Wernicki, Andrzej

2016-06-13

The objective of our study is to evaluate the potential use of Amplified 16S Ribosomal DNA Restriction Analysis (16S-ARDRA) and MALDI-TOF mass spectrometry (MS) as methods for species identification of Lactobacillus strains in poultry. A total of 80 Lactobacillus strains isolated from the cloaca of chicken, geese and turkeys were identified to the species level by MALDI-TOF MS (on-plate extraction method) and 16S-ARDRA. The two techniques produced comparable classification results, some of which were additionally confirmed by sequencing of 16S rDNA. MALDI-TOF MS enabled rapid species identification but produced more than one reliable identification result for 16.25 % of examined strains (mainly of the species L. johnsonii). For 30 % of isolates intermediate log(scores) of 1.70-1.99 were obtained, indicating correct genus identification but only presumptive species identification. The 16S-ARDRA protocol was based on digestion of 16S rDNA with the restriction enzymes MseI, HinfI, MboI and AluI. This technique was able to distinguish 17 of the 19 Lactobacillus reference species tested and enabled identification of all 80 wild isolates. L. salivarius dominated among the 15 recognized species, followed by L. johnsonii and L. ingluviei. The MALDI-TOF MS and 16S-ARDRA assays are valuable tools for the identification of avian lactobacilli to the species level. MALDI-TOF MS is a fast, simple and cost-effective technique, and despite generating a high percentage of results with a log(score) <2.00, the on-plate extraction method is characterized by high-performance. For samples for which Biotyper produces more than one reliable result, MALDI-TOF MS must be used in combination with genotypic techniques to achieve unambiguous results. 16S-ARDRA is simple, repetitive method with high power of discrimination, whose sole limitation is its inability to discriminate between species with very high 16S rDNA sequence homology, such as L. casei and L. zeae. The assays can be used for discrimination of Lactobacillus bacteria from different habitats.

Genomic evolution of Saccharomyces cerevisiae under Chinese rice wine fermentation.

PubMed

Li, Yudong; Zhang, Weiping; Zheng, Daoqiong; Zhou, Zhan; Yu, Wenwen; Zhang, Lei; Feng, Lifang; Liang, Xinle; Guan, Wenjun; Zhou, Jingwen; Chen, Jian; Lin, Zhenguo

2014-09-10

Rice wine fermentation represents a unique environment for the evolution of the budding yeast, Saccharomyces cerevisiae. To understand how the selection pressure shaped the yeast genome and gene regulation, we determined the genome sequence and transcriptome of a S. cerevisiae strain YHJ7 isolated from Chinese rice wine (Huangjiu), a popular traditional alcoholic beverage in China. By comparing the genome of YHJ7 to the lab strain S288c, a Japanese sake strain K7, and a Chinese industrial bioethanol strain YJSH1, we identified many genomic sequence and structural variations in YHJ7, which are mainly located in subtelomeric regions, suggesting that these regions play an important role in genomic evolution between strains. In addition, our comparative transcriptome analysis between YHJ7 and S288c revealed a set of differentially expressed genes, including those involved in glucose transport (e.g., HXT2, HXT7) and oxidoredutase activity (e.g., AAD10, ADH7). Interestingly, many of these genomic and transcriptional variations are directly or indirectly associated with the adaptation of YHJ7 strain to its specific niches. Our molecular evolution analysis suggested that Japanese sake strains (K7/UC5) were derived from Chinese rice wine strains (YHJ7) at least approximately 2,300 years ago, providing the first molecular evidence elucidating the origin of Japanese sake strains. Our results depict interesting insights regarding the evolution of yeast during rice wine fermentation, and provided a valuable resource for genetic engineering to improve industrial wine-making strains. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Analysis of potential fumonisin-producing Fusarium species in corn products from three main maize-producing areas in eastern China.

PubMed

Zhang, Liping; Wang, Jiansheng; Zhang, Chulong; Wang, Qiaomei

2013-02-01

Fusarium species are common fungal contaminants of maize and a number of them can produce mycotoxin fumonisins. China is one of the largest maize producers in the world. This study investigated the contamination of maize samples from three areas in eastern China by Fusarium and fumonisin-producing fungi as well as their fumonisin-producing potential. A total of 22 Fusarium strains were isolated, 19 of which were able to produce fumonisin. Among the 19 strains, 16 belonged to F. verticillioides, two to F. subglutinans and one to F. proliferatum. The majority (17/19) of the fumonisin-forming strains were high FB(1) producers, which is a potential health risk for the population in these areas. Fusarium contamination in samples from the mideastern area was the most serious (11 Fusarium strains, with nine producing fumonisin, isolated from 24 samples), followed by the northeastern area (nine Fusarium strains, with all nine producing fumonisin, isolated from 21 samples) and the southeastern area (two Fusarium strains, with one producing fumonisin, isolated from 19 samples). Although the overall levels of FBs and contamination by fumonisin-producing fungi in corn samples were not serious, the contaminating Fusarium strains possessed fairly strong toxicogenic ability and potential risk for food safety. Copyright © 2012 Society of Chemical Industry.

Lactobacillus rhamnosus GG-supplemented formula expands butyrate-producing bacterial strains in food allergic infants.

PubMed

Berni Canani, Roberto; Sangwan, Naseer; Stefka, Andrew T; Nocerino, Rita; Paparo, Lorella; Aitoro, Rosita; Calignano, Antonio; Khan, Aly A; Gilbert, Jack A; Nagler, Cathryn R

2016-03-01

Dietary intervention with extensively hydrolyzed casein formula supplemented with Lactobacillus rhamnosus GG (EHCF+LGG) accelerates tolerance acquisition in infants with cow's milk allergy (CMA). We examined whether this effect is attributable, at least in part, to an influence on the gut microbiota. Fecal samples from healthy controls (n=20) and from CMA infants (n=19) before and after treatment with EHCF with (n=12) and without (n=7) supplementation with LGG were compared by 16S rRNA-based operational taxonomic unit clustering and oligotyping. Differential feature selection and generalized linear model fitting revealed that the CMA infants have a diverse gut microbial community structure dominated by Lachnospiraceae (20.5±9.7%) and Ruminococcaceae (16.2±9.1%). Blautia, Roseburia and Coprococcus were significantly enriched following treatment with EHCF and LGG, but only one genus, Oscillospira, was significantly different between infants that became tolerant and those that remained allergic. However, most tolerant infants showed a significant increase in fecal butyrate levels, and those taxa that were significantly enriched in these samples, Blautia and Roseburia, exhibited specific strain-level demarcations between tolerant and allergic infants. Our data suggest that EHCF+LGG promotes tolerance in infants with CMA, in part, by influencing the strain-level bacterial community structure of the infant gut.

Lactobacillus rhamnosus GG-supplemented formula expands butyrate-producing bacterial strains in food allergic infants

PubMed Central

Berni Canani, Roberto; Sangwan, Naseer; Stefka, Andrew T; Nocerino, Rita; Paparo, Lorella; Aitoro, Rosita; Calignano, Antonio; Khan, Aly A; Gilbert, Jack A; Nagler, Cathryn R

2016-01-01

Dietary intervention with extensively hydrolyzed casein formula supplemented with Lactobacillus rhamnosus GG (EHCF+LGG) accelerates tolerance acquisition in infants with cow's milk allergy (CMA). We examined whether this effect is attributable, at least in part, to an influence on the gut microbiota. Fecal samples from healthy controls (n=20) and from CMA infants (n=19) before and after treatment with EHCF with (n=12) and without (n=7) supplementation with LGG were compared by 16S rRNA-based operational taxonomic unit clustering and oligotyping. Differential feature selection and generalized linear model fitting revealed that the CMA infants have a diverse gut microbial community structure dominated by Lachnospiraceae (20.5±9.7%) and Ruminococcaceae (16.2±9.1%). Blautia, Roseburia and Coprococcus were significantly enriched following treatment with EHCF and LGG, but only one genus, Oscillospira, was significantly different between infants that became tolerant and those that remained allergic. However, most tolerant infants showed a significant increase in fecal butyrate levels, and those taxa that were significantly enriched in these samples, Blautia and Roseburia, exhibited specific strain-level demarcations between tolerant and allergic infants. Our data suggest that EHCF+LGG promotes tolerance in infants with CMA, in part, by influencing the strain-level bacterial community structure of the infant gut. PMID:26394008

Antibacterial activity of Lactobacillus acidophilus strains isolated from honey marketed in Malaysia against selected multiple antibiotic resistant (MAR) Gram-positive bacteria.

PubMed

Aween, Mohamed Mustafa; Hassan, Zaiton; Muhialdin, Belal J; Eljamel, Yossra A; Al-Mabrok, Asma Saleh W; Lani, Mohd Nizam

2012-07-01

A total of 32 lactic acid bacteria (LAB) were isolated from 13 honey samples commercially marketed in Malaysia, 6 strains identified as Lactobacillus acidophilus by API CHL50. The isolates had antibacterial activities against multiple antibiotic resistant's Staphylococcus aureus (25 to 32 mm), Staphylococcus epidermis (14 to 22 mm) and Bacillus subtilis (12 to 19 mm) in the agar overlay method after 24 h incubation at 30 °C. The crude supernatant was heat stable at 90 °C and 121 °C for 1 h. Treatment with proteinase K and RNase II maintained the antimicrobial activity of all the supernatants except sample H006-A and H010-G. All the supernatants showed antimicrobial activities against target bacteria at pH 3 and pH 5 but not at pH 6 within 72 h incubation at 30 °C. S. aureus was not inhibited by sample H006-A isolated from Libyan honey and sample H008-D isolated from Malaysian honey at pH 5, compared to supernatants from other L. acidophilus isolates. The presence of different strains of L. acidophilus in honey obtained from different sources may contribute to the differences in the antimicrobial properties of honey. © 2012 Institute of Food Technologists®

Gains and Losses of Transcription Factor Binding Sites in Saccharomyces cerevisiae and Saccharomyces paradoxus

PubMed Central

Schaefke, Bernhard; Wang, Tzi-Yuan; Wang, Chuen-Yi; Li, Wen-Hsiung

2015-01-01

Gene expression evolution occurs through changes in cis- or trans-regulatory elements or both. Interactions between transcription factors (TFs) and their binding sites (TFBSs) constitute one of the most important points where these two regulatory components intersect. In this study, we investigated the evolution of TFBSs in the promoter regions of different Saccharomyces strains and species. We divided the promoter of a gene into the proximal region and the distal region, which are defined, respectively, as the 200-bp region upstream of the transcription starting site and as the 200-bp region upstream of the proximal region. We found that the predicted TFBSs in the proximal promoter regions tend to be evolutionarily more conserved than those in the distal promoter regions. Additionally, Saccharomyces cerevisiae strains used in the fermentation of alcoholic drinks have experienced more TFBS losses than gains compared with strains from other environments (wild strains, laboratory strains, and clinical strains). We also showed that differences in TFBSs correlate with the cis component of gene expression evolution between species (comparing S. cerevisiae and its sister species Saccharomyces paradoxus) and within species (comparing two closely related S. cerevisiae strains). PMID:26220934

Two-dimensional right ventricular strain by speckle tracking for assessment of longitudinal right ventricular function after paediatric congenital heart disease surgery.

PubMed

Karsenty, Clement; Hadeed, Khaled; Dulac, Yves; Semet, Florent; Alacoque, Xavier; Breinig, Sophie; Leobon, Bertrand; Acar, Philippe; Hascoet, Sebastien

2017-03-01

Right ventricular (RV) function is a prognostic marker of cardiac disease in children. Speckle tracking has been developed to assess RV longitudinal shortening, the dominant deformation during systole; little is known about its feasibility in children with congenital heart disease (CHD). To evaluate the feasibility and reproducibility of RV two-dimensional (2D) strain assessed by speckle tracking in infants undergoing CHD surgery compared with conventional markers. In this prospective single-centre study, RV peak systolic strain (RV-PSS) was measured using 2D speckle tracking in 37 consecutive children undergoing CHD surgery. Examinations were performed the day before surgery, a few hours after surgery and before discharge. Relationships with the z score of tricuspid annular plane systolic excursion (TAPSE) and tricuspid annular systolic velocity (TA Sa) were assessed. Median (interquartile range) age was 19 months (5-63); median weight was 9.2 kg (5.3-18.0). RV-PSS analysis was feasible in 92.9% (95% confidence interval [CI]: 86.0-97.1) of examinations. The coefficient of variation was 9.7% (95% CI: 7.4-11.9) for intraobserver variability and 15.1% (95% CI: 12.7-17.6) for interobserver variability. Correlations between RV-PSS and z score of TAPSE and TA Sa were strong (r=0.71, P<0.0001 and r=0.70, P<0.0001, respectively). RV-PSS was significantly reduced after surgery compared with baseline (-10.5±2.9% vs. -19.5±4.8%; P<0.0001) and at discharge (-13.5±4.0% vs. -19.5±4.8%; P<0.0001). Similar evolutions were observed with TAPSE and TA Sa (both P<0.0001). RV longitudinal strain by speckle tracking is a feasible and reproducible method of assessing perioperative evolution of RV function in children with CHD. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

A novel two-dimensional dynamic anal ultrasonography technique to assess anismus comparing with three-dimensional echodefecography.

PubMed

Murad-Regadas, S M; Regadas, F S P; Barreto, R G L; Rodrigues, L V; de Souza, M H L P

2009-10-01

The aim of this prospective study was to test two-dimensional dynamic anorectal ultrasonography (2D-DAUS) in the assessment of anismus and compare it with echodefecography (ECD). Fifty consecutive female patients with outlet delay were submitted to 2D and 3D-DAUS, measuring the relaxing or contracting puborectalis muscle angle during straining. The patients were assigned to one of two groups based on ECD findings. Group I consisted of 29 patients without anismus and group II included 21 patients diagnosed with anismus. Subsequently 2D-DAUS images were checked for anismus and compared with ECD findings. Upon straining, the angle produced by the movement of the puborectalis muscle decreased in 26 out of the 29 (89.6%) patients of group I and increased 19 out of the 21 (90.4%) patients of group II. The mean angle during straining differed significantly between group I and group II. The index of agreement between the two scanning modes was 89.6% (26/29) for group I (Kappa: 0.796; CI: 95%; range: 0.51-1.0) and 90.4% (19/21) for group II (Kappa: 0.796; CI: 95%; range: 0.51-1.0). Two-dimensional dynamic anal ultrasonography can be used as an alternative method to assess patients with anismus, although the 3-D modality is more precise to evaluate the PR angle as the sphincters integrity as the whole muscle length is clearly visualized.

Establishment of the first international repository for transfusion-relevant bacteria reference strains: ISBT working party transfusion-transmitted infectious diseases (WP-TTID), subgroup on bacteria.

PubMed

Störmer, M; Arroyo, A; Brachert, J; Carrero, H; Devine, D; Epstein, J S; Gabriel, C; Gelber, C; Goodrich, R; Hanschmann, K-M; Heath, D G; Jacobs, M R; Keil, S; de Korte, D; Lambrecht, B; Lee, C-K; Marcelis, J; Marschner, S; McDonald, C; McGuane, S; McKee, M; Müller, T H; Muthivhi, T; Pettersson, A; Radziwon, P; Ramirez-Arcos, S; Reesink, H W; Rojo, J; Rood, I; Schmidt, M; Schneider, C K; Seifried, E; Sicker, U; Wendel, S; Wood, E M; Yomtovian, R A; Montag, T

2012-01-01

Bacterial contamination of platelet concentrates (PCs) still remains a significant problem in transfusion with potential important clinical consequences, including death. The International Society of Blood Transfusion Working Party on Transfusion-Transmitted Infectious Diseases, Subgroup on Bacteria, organised an international study on Transfusion-Relevant Bacteria References to be used as a tool for development, validation and comparison of both bacterial screening and pathogen reduction methods. Four Bacteria References (Staphylococcus epidermidis PEI-B-06, Streptococcus pyogenes PEI-B-20, Klebsiella pneumoniae PEI-B-08 and Escherichia coli PEI-B-19) were selected regarding their ability to proliferate to high counts in PCs and distributed anonymised to 14 laboratories in 10 countries for identification, enumeration and bacterial proliferation in PCs after low spiking (0·3 and 0·03 CFU/ml), to simulate contamination occurring during blood donation. Bacteria References were correctly identified in 98% of all 52 identifications. S. pyogenes and E. coli grew in PCs in 11 out of 12 laboratories, and K. pneumoniae and S. epidermidis replicated in all participating laboratories. The results of bacterial counts were very consistent between laboratories: the 95% confidence intervals were for S. epidermidis: 1·19-1·32 × 10(7) CFU/ml, S. pyogenes: 0·58-0·69 × 10(7) CFU/ml, K. pneumoniae: 18·71-20·26 × 10(7) CFU/ml and E. coli: 1·78-2·10 × 10(7) CFU/ml. The study was undertaken as a proof of principle with the aim to demonstrate (i) the quality, stability and suitability of the bacterial strains for low-titre spiking of blood components, (ii) the property of donor-independent proliferation in PCs, and (iii) their suitability for worldwide shipping of deep frozen, blinded pathogenic bacteria. These aims were successfully fulfilled. The WHO Expert Committee Biological Standardisation has approved the adoption of these four bacteria strains as the first Repository for Transfusion-Relevant Bacteria Reference Strains and, additionally, endorsed as a project the addition of six further bacteria strain preparations suitable for control of platelet contamination as the next step of enlargement of the repository. © 2011 The Author(s). Vox Sanguinis © 2011 International Society of Blood Transfusion.

Thioclava electrotropha sp. nov., a versatile electrode and sulfur-oxidizing bacterium from marine sediments.

PubMed

Chang, Rachel; Bird, Lina; Barr, Casey; Osburn, Magdalena; Wilbanks, Elizabeth; Nealson, Kenneth; Rowe, Annette

2018-05-01

A taxonomic and physiologic characterization was carried out on Thioclava strain ElOx9 T , which was isolated from a bacterial consortium enriched on electrodes poised at electron donating potentials. The isolate is Gram-negative, catalase-positive and oxidase-positive; the cells are motile short rods. The bacterium is facultatively anaerobic with the ability to utilize nitrate as an electron acceptor. Autotrophic growth with H2 and S 0 (oxidized to sulfate) was observed. The isolate also grows heterotrophically with organic acids and sugars. Growth was observed at salinities from 0 to 10% NaCl and at temperatures from 15 to 41 °C. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain belongs in the genus Thioclava; it had the highest sequence similarity of 98.8 % to Thioclava atlantica 13D2W-2 T , followed by Thioclava dalianensis DLFJ1-1 T with 98.5 % similarity, Thioclava pacifica TL 2 T with 97.7 % similarity, and then Thioclava indica DT23-4 T with 96.9 %. All other sequence similarities were below 97 % to characterized strains. The digital DNA-DNA hybridization estimated when compared to T. atlantica 13D2W-2 T , T. dalianensis DLFJ1-1 T , T. pacifica TL 2 T and T. indica DT23-4 T were 15.8±2.1, 16.7+2.1, 14.3±1.9 and 18.3±2.1 %. The corresponding average nucleotide identity values between these strains were determined to be 65.1, 67.8, 68.4 and 64.4 %, respectively. The G+C content of the chromosomal DNA is 63.4 mol%. Based on these results, a novel species Thioclava electrotropha sp. nov. is proposed, with the type strain ElOx9 T (=DSM 103712 T =ATCC TSD-100 T ).

Production, optimization and characterization of fibrinolytic enzyme by Bacillus subtilis RJAS19.

PubMed

Kumar, D J Mukesh; Rakshitha, R; Vidhya, M Annu; Jennifer, P Sharon; Prasad, Sandip; Kumar, M Ravi; Kalaichelvan, P T

2014-04-01

The present study aimed at the production, purification and characterization of fibrinolytic nattokinase enzyme from the bacteria isolated from natto food. For the purpose, a fibrinolytic bacterium was isolated and identified as Bacillus subtilis based on 16S rDNA sequence analysis. The strain was employed for the production and optimization of fibrinolytic enzyme. The strain showed better enzyme production during 72nd h of incubation time with 50 degrees C at the pH 9. The lactose and peptone were found to be increasing the enzyme production rate. The enzyme produced was purified and also characterized with the help of SDS-PAGE analysis. The activity and stability profile of the purified enzyme was tested against different temperature and pH. The observations suggesting that the potential of fibrinolytic enzyme produced by Bacillus subtilis RJAS 19 for its applications in preventive medicines.

Detection of 1-nitropyrene in yakitori (grilled chicken).

PubMed

Kinouchi, T; Tsutsui, H; Ohnishi, Y

1986-01-01

Pieces of raw chicken with or without a marinating sauce were grilled over a city gas flame, extracted with benzene-ethanol (4:1) by ultrasonication and fractionated into diethyl ether-soluble neutral, acidic and basic fractions. The mutagenicity of these fractions was measured with Salmonella typhimurium strains TA100, TA98, TA98NR and TA98/1,8-DNP6 in the presence and absence of a 9000 X g post-mitochondrial supernatant from Aroclor 1254-treated Sprague-Dawley rat liver (S9 mix). The basic fraction of yakitori without the sauce was more mutagenic than the other fractions for S. typhimurium strain TA98 in the presence of S9 mix. This is probably due to the presence of amino acid or protein pyrolysates. However, when the chicken was grilled with the sauce, the basic fraction showed lower mutagenicity for strain TA98 in the presence of S9 mix than did the same fraction without the sauce. The neutral fraction of yakitori with sauce showed high mutagenicity for strain TA98 in the absence of S9 mix, but low mutagenicity for strains TA98NR and TA98/1,8-DNP6, suggesting that this fraction might contain nitropyrenes (NPs). The neutral fraction of yakitori was analyzed by high-performance liquid chromatography (HPLC). The neutral fraction of the chicken grilled with the sauce for 3, 5 and 7 min contained 3.8, 19 and 43 ng, respectively, of 1-NP per gram of yakitori accounting for 3.0, 2.7 and 1.3%, respectively, of the total mutagenicity.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparisons of Transcriptional Profiles of Gut Genes between Cry1Ab-Resistant and Susceptible Strains of Ostrinia nubilalis Revealed Genes Possibly Related to the Adaptation of Resistant Larvae to Transgenic Cry1Ab Corn.

PubMed

Yao, Jianxiu; Zhu, Yu-Cheng; Lu, Nanyan; Buschman, Lawrent L; Zhu, Kun Yan

2017-01-30

A microarray developed on the basis of 2895 unique transcripts from larval gut was used to compare gut gene expression profiles between a laboratory-selected Cry1Ab-resistant (R) strain and its isoline susceptible (S) strain of the European corn borer (Ostrinia nubilalis) after the larvae were fed the leaves of transgenic corn (MON810) expressing Cry1Ab or its non-transgenic isoline for 6 h. We revealed 398 gut genes differentially expressed (i.e., either up- or down-regulated genes with expression ratio ≥2.0) in S-strain, but only 264 gut genes differentially expressed in R-strain after being fed transgenic corn leaves. Although the percentages of down-regulated genes among the total number of differentially expressed genes (50% in S-strain and 45% in R-strain) were similar between the R- and S-strains, the expression ratios of down-regulated genes were much higher in S-strain than in R-strain. We revealed that 17 and 9 significantly up- or down-regulated gut genes from S and R-strain, respectively, including serine proteases and aminopeptidases. These genes may be associated with Cry1Ab toxicity by degradation, binding, and cellular defense. Overall, our study suggests enhanced adaptation of Cry1Ab-resistant larvae on transgenic Cry1Ab corn as revealed by lower number and lower ratios of differentially expressed genes in R-strain than in S-strain of O. nubilalis.

Preliminary study on the antimicrobial susceptibility pattern related to the genotype of Vibrio vulnificus strains isolated in the north-western Adriatic Sea coastal area.

PubMed

Serratore, Patrizia; Zavatta, Emanuele; Fiocchi, Eleonora; Serafini, Emanuele; Serraino, Andrea; Giacometti, Federica; Bignami, Giorgia

2017-10-20

V. vulnificus is a Gram-negative bacterium, commonly found in estuarine and coastal habitats, that can infect humans through seafood consumption or wound exposure. This study represents the first attempt to correlate the genotype of Vibrio vulnificus strains isolated in the north-western Adriatic Sea coastal area, with their antimicrobial susceptibility patterns. On the whole, 40 V. vulnificus strains, isolated from shellfish (n=20), different coastal water bodies (n=19), and the blood of a Carretta carretta turtle (n=1), were utilized. All strains were positive for the species-specific genes vvh A and hsp , with high variability for other markers: 55% (22 out of 40) resulted of the environmental (E) genotype ( vcg E, 16S rRNA type A, CPS2 or CPS0), 10% (4 out of 40) of the clinical (C) genotype ( vcg C, 16S rRNA type B, CPS1), and 35% (14 out of 40) of the mixed (M) genotype, possessing both E and C markers. The antimicrobial susceptibility was assayed by the diffusion method on agar, according to the Clinical Laboratory Standards Institute (CLSI), utilizing the following commercial disks (Oxoid): ampicillin (AMP), ampicillin- sulbactam (SAM), piperacillin (PRL), cefazolin (KZ), cefotaxime(CTX), ceftazidime (CAZ), imipenem (IPM), meropenem (MEM), amikacin (AK), gentamicin(CN), tetracycline(TE), ciprofloxacin (CIP), levofloxacin (LEV), trimethoprim-sulfamethoxazole (SXT), and chloramphenicol (C). 75% of the strains, (n=30) including all C strains, was sensitive to all the tested antibiotics, whereas E strains showed intermediate sensitivity to AK (2 strains), CIP and CAZ (1 strain), TE (1 strain) and resistance to KZ (1 strain), and 4 M strains showed I to AK.

Diversity and Ecophysiology of New Isolates of Extremely Acidophilic CS2-Converting Acidithiobacillus Strains

PubMed Central

Smeulders, Marjan J.; Pol, Arjan; Zandvoort, Marcel H.; Jetten, Mike S. M.

2013-01-01

Biofiltration of industrial carbon disulfide (CS2)-contaminated waste air streams results in the acidification of biofilters and therefore reduced performance, high water use, and increased costs. To address these issues, we isolated 16 extremely acidophilic CS2-converting Acidithiobacillus thiooxidans strains that tolerated up to 6% (vol/vol) sulfuric acid. The ecophysiological properties of five selected strains (2Bp, Sts 4-3, S1p, G8, and BBW1) were compared. These five strains had pH optima between 1 (2Bp) and 2 (S1p). Their affinities for CS2 ranged between 80 (G8) and 130 (2Bp) μM. Strains S1p, G8, and BBW1 had more hydrophobic cell surfaces and produced less extracellular polymeric substance than did strains 2Bp and Sts 4-3. All five strains converted about 80% of the S added as CS2 to S0 when CS2 was supplied in excess. The rate of S0 consumption varied between 7 (Sts 4-3) and 63 (S1p) nmol O2 min−1 ml culture−1. Low S0 consumption rates correlated partly with low levels of cell attachment to externally produced S0 globules. During chemostat growth, the relative amount of CS2 hydrolase in the cell increased with decreasing growth rates. This resulted in more S0 accumulation during CS2 overloads at low growth rates. Intermittent interruptions of the CS2 supply affected all five strains. Strains S1p, G8, and BBW1 recovered from 24 h of starvation within 4 h, and strains 2Bp and Sts 4-3 recovered within 24 h after CS2 was resupplied. We recommend the use of mixtures of Acidithiobacillus strains in industrial biofilters. PMID:23995926

Organic acids for control of Salmonella in different feed materials.

PubMed

Koyuncu, Sevinc; Andersson, Mats Gunnar; Löfström, Charlotta; Skandamis, Panagiotis N; Gounadaki, Antonia; Zentek, Jürgen; Häggblom, Per

2013-04-18

Salmonella control in animal feed is important in order to protect animal and public health. Organic acids is one of the control measures used for treatment of Salmonella contaminated feed or feed ingredients. In the present study, the efficacy of formic acid (FA) and different blends of FA, propionic acid (PA) and sodium formate (SF) was investigated. Four Salmonella strains isolated from feed were assayed for their acid tolerance. Also, the effect of lower temperatures (5°C and 15°C) compared to room temperature was investigated in rape seed and soybean meal. The efficacy of acid treatments varied significantly between different feed materials. The strongest reduction was seen in pelleted and compound mash feed (2.5 log10 reduction) followed by rapeseed meal (1 log10 reduction) after 5 days exposure. However, in soybean meal the acid effects were limited (less than 0.5 log10 reduction) even after several weeks' exposure. In all experiments the survival curves showed a concave shape, with a fast initial death phase followed by reduction at a slower rate during the remaining time of the experiment.No difference in Salmonella reduction was observed between FA and a blend of FA and PA, whereas a commercial blend of FA and SF (Amasil) was slightly more efficacious (0.5-1 log10 reduction) than a blend of FA and PA (Luprocid) in compound mash feed. The Salmonella Infantis strain was found to be the most acid tolerant strain followed by, S. Putten, S. Senftenberg and S. Typhimurium. The tolerance of the S. Infantis strain compared with the S. Typhimurium strain was statistically significant (p<0.05). The lethal effect of FA on the S. Typhimurium strain and the S. Infantis strain was lower at 5°C and 15°C compared to room temperatures. Acid treatment of Salmonella in feed is a matter of reducing the number of viable bacterial cells rather than eliminating the organism. Recommendations on the use of acids for controlling Salmonella in feed should take into account the relative efficacy of acid treatment in different feed materials, the variation in acid tolerance between different Salmonella strains, and the treatment temperature.

Investigating the Molecular Mechanisms of Organophosphate and Pyrethroid Resistance in the Fall Armyworm Spodoptera frugiperda

PubMed Central

Carvalho, Renato A.; Omoto, Celso; Field, Linda M.; Williamson, Martin S.; Bass, Chris

2013-01-01

The fall armyworm Spodoptera frugiperda is an economically important pest of small grain crops that occurs in all maize growing regions of the Americas. The intensive use of chemical pesticides for its control has led to the selection of resistant populations, however, to date, the molecular mechanisms underlying resistance have not been characterised. In this study the mechanisms involved in the resistance of two S. frugiperda strains collected in Brazil to chlorpyrifos (OP strain) or lambda-cyhalothrin (PYR strain) were investigated using molecular and genomic approaches. To examine the possible role of target-site insensitivity the genes encoding the organophosphate (acetylcholinesterase, AChE) and pyrethroid (voltage-gated sodium channel, VGSC) target-site proteins were PCR amplified. Sequencing of the S. frugiperda ace-1 gene identified several nucleotide changes in the OP strain when compared to a susceptible reference strain (SUS). These result in three amino acid substitutions, A201S, G227A and F290V, that have all been shown previously to confer organophosphate resistance in several other insect species. Sequencing of the gene encoding the VGSC in the PYR strain, identified mutations that result in three amino acid substitutions, T929I, L932F and L1014F, all of which have been shown previously to confer knockdown/super knockdown-type resistance in several arthropod species. To investigate the possible role of metabolic detoxification in the resistant phenotype of the OP and PYR stains all EST sequences available for S. frugiperda were used to design a gene-expression microarray. This was then used to compare gene expression in the resistant strains with the susceptible reference strain. Members of several gene families, previously implicated in metabolic resistance in other insects were found to be overexpressed in the resistant strains including glutathione S-transferases, cytochrome P450s and carboxylesterases. Taken together these results provide evidence that both target-site and metabolic mechanisms underlie the resistance of S. frugiperda to pyrethroids and organophosphates. PMID:23614047

Investigating the molecular mechanisms of organophosphate and pyrethroid resistance in the fall armyworm Spodoptera frugiperda.

PubMed

Carvalho, Renato A; Omoto, Celso; Field, Linda M; Williamson, Martin S; Bass, Chris

2013-01-01

The fall armyworm Spodoptera frugiperda is an economically important pest of small grain crops that occurs in all maize growing regions of the Americas. The intensive use of chemical pesticides for its control has led to the selection of resistant populations, however, to date, the molecular mechanisms underlying resistance have not been characterised. In this study the mechanisms involved in the resistance of two S. frugiperda strains collected in Brazil to chlorpyrifos (OP strain) or lambda-cyhalothrin (PYR strain) were investigated using molecular and genomic approaches. To examine the possible role of target-site insensitivity the genes encoding the organophosphate (acetylcholinesterase, AChE) and pyrethroid (voltage-gated sodium channel, VGSC) target-site proteins were PCR amplified. Sequencing of the S. frugiperda ace-1 gene identified several nucleotide changes in the OP strain when compared to a susceptible reference strain (SUS). These result in three amino acid substitutions, A201S, G227A and F290V, that have all been shown previously to confer organophosphate resistance in several other insect species. Sequencing of the gene encoding the VGSC in the PYR strain, identified mutations that result in three amino acid substitutions, T929I, L932F and L1014F, all of which have been shown previously to confer knockdown/super knockdown-type resistance in several arthropod species. To investigate the possible role of metabolic detoxification in the resistant phenotype of the OP and PYR stains all EST sequences available for S. frugiperda were used to design a gene-expression microarray. This was then used to compare gene expression in the resistant strains with the susceptible reference strain. Members of several gene families, previously implicated in metabolic resistance in other insects were found to be overexpressed in the resistant strains including glutathione S-transferases, cytochrome P450s and carboxylesterases. Taken together these results provide evidence that both target-site and metabolic mechanisms underlie the resistance of S. frugiperda to pyrethroids and organophosphates.

Enological Qualities and Interactions Between Native Yeast and Lactic Acid Bacteria from Queretaro, Mexico.

PubMed

Miranda-Castilleja, Dalia E; Martínez-Peniche, Ramón Á; Nadal Roquet-Jalmar, Montserrat; Aldrete-Tapia, J Alejandro; Arvizu-Medrano, Sofía M

2018-06-15

Despite the importance of strain compatibility, most of the enological strain selection studies are carried out separately on yeasts and lactic acid bacteria (LAB). In this study, the enological traits and interactions between native yeasts and LAB were studied. The H 2 S and acetic acid production, growth rates at 8 °C, killer phenotypes, flocculation, and tolerance to must and wine inhibitors were determined for 25 Saccharomyces yeasts. The ability to grow under two wine-like conditions was also determined in 37 LAB (Oenococcus oeni and Lactobacillus plantarum). The yeast-LAB compatibility of selected strains was tested in a sequential scheme. Finally, microvinification trials were performed using two strains from each group to determine the efficiencies and quality parameters. The phenotypic characterization by the K-means and hierarchical clusters indicated a correlation between flocculation and optical density increase in simulated must and wine medium (r = -0.415) and grouped the prominent yeasts SR19, SR26, and N05 as moderately flocculent, killer, acid producing, and highly tolerant strains. Among the LAB, L. plantarum FU39 grew 230% more than the rest. With regard to interactions, LAB growth stimulation (14-fold on average) due to the previous action of yeasts, particularly of SR19, was observed. The final quality of all wines was similar, but yeast SR19 performed a faster and more efficient fermentation than did N05, Also L. plantarum FU39 fermented faster than did O. oeni VC32. The use of quantitative data, and multivariate analyses allowed an integrative approach to the selection of a compatible and efficient pair of enological yeast-LAB strains. An alternative scheme is proposed for the joint selection of yeast and lactic acid bacteria strains, which allows us to foresee the interactions that may occur between them during winemaking. The kinetic parameters, turbidimetrically measured and analyzed by multivariate methods, simplify the detection of outstanding selectable microorganisms. This methodology can be implemented at any cellar or even any fermentative industry that aims to select compatible yeast and lactic acid bacteria. © 2018 Institute of Food Technologists®.

Contribution of the Collagen-Binding Proteins of Streptococcus mutans to Bacterial Colonization of Inflamed Dental Pulp.

PubMed

Nomura, Ryota; Ogaya, Yuko; Nakano, Kazuhiko

2016-01-01

Streptococcus mutans is a major pathogen of dental caries. Collagen-binding proteins (CBPs) (approximately 120 kDa), termed Cnm and Cbm, are regarded as important cell surface antigens related to the adherence of S. mutans to collagenous tissue. Furthermore, CBP-positive S. mutans strains are associated with various systemic diseases involving bacteremia, such as infective endocarditis. Endodontic infection is considered to be an important cause of bacteremia, but little is known regarding the presence of S. mutans in dental pulp tissue. In the present study, the distribution and virulence of S. mutans in dental pulp tissues were investigated by focusing on CBPs. Adhesion and invasion properties of various S. mutans strains were analyzed using human dental pulp fibroblasts (HDPFs). CBP-positive strains had a significantly higher rate of adhesion to HDPFs compared with CBP-defective isogenic mutant strains (P<0.001). In addition, CBP-positive strains induced HDPF proliferation, which is a possible mechanism related to development of hyperplastic pulpitis. The distribution of S. mutans strains isolated from infected root canal specimens was then analyzed by PCR. We found that approximately 50% of the root canal specimens were positive for S. mutans. Approximately 20% of these strains were Cnm-positive, while no Cbm-positive strains were isolated. The Cnm-positive strains isolated from the specimens showed adhesion to HDPFs. Our results suggest that CBP-positive S. mutans strains exhibit high colonization in dental pulp. This could be a possible virulence factor for various systemic diseases.

Comparative genomics reveals adaptation by Alteromonas sp. SN2 to marine tidal-flat conditions: cold tolerance and aromatic hydrocarbon metabolism.

PubMed

Math, Renukaradhya K; Jin, Hyun Mi; Kim, Jeong Myeong; Hahn, Yoonsoo; Park, Woojun; Madsen, Eugene L; Jeon, Che Ok

2012-01-01

Alteromonas species are globally distributed copiotrophic bacteria in marine habitats. Among these, sea-tidal flats are distinctive: undergoing seasonal temperature and oxygen-tension changes, plus periodic exposure to petroleum hydrocarbons. Strain SN2 of the genus Alteromonas was isolated from hydrocarbon-contaminated sea-tidal flat sediment and has been shown to metabolize aromatic hydrocarbons there. Strain SN2's genomic features were analyzed bioinformatically and compared to those of Alteromonas macleodii ecotypes: AltDE and ATCC 27126. Strain SN2's genome differs from that of the other two strains in: size, average nucleotide identity value, tRNA genes, noncoding RNAs, dioxygenase gene content, signal transduction genes, and the degree to which genes collected during the Global Ocean Sampling project are represented. Patterns in genetic characteristics (e.g., GC content, GC skew, Karlin signature, CRISPR gene homology) indicate that strain SN2's genome architecture has been altered via horizontal gene transfer (HGT). Experiments proved that strain SN2 was far more cold tolerant, especially at 5°C, than the other two strains. Consistent with the HGT hypothesis, a total of 15 genomic islands in strain SN2 likely confer ecological fitness traits (especially membrane transport, aromatic hydrocarbon metabolism, and fatty acid biosynthesis) specific to the adaptation of strain SN2 to its seasonally cold sea-tidal flat habitat.

Comparative Genomics Reveals Adaptation by Alteromonas sp. SN2 to Marine Tidal-Flat Conditions: Cold Tolerance and Aromatic Hydrocarbon Metabolism

PubMed Central

Math, Renukaradhya K.; Jin, Hyun Mi; Kim, Jeong Myeong; Hahn, Yoonsoo; Park, Woojun; Madsen, Eugene L.; Jeon, Che Ok

2012-01-01

Alteromonas species are globally distributed copiotrophic bacteria in marine habitats. Among these, sea-tidal flats are distinctive: undergoing seasonal temperature and oxygen-tension changes, plus periodic exposure to petroleum hydrocarbons. Strain SN2 of the genus Alteromonas was isolated from hydrocarbon-contaminated sea-tidal flat sediment and has been shown to metabolize aromatic hydrocarbons there. Strain SN2's genomic features were analyzed bioinformatically and compared to those of Alteromonas macleodii ecotypes: AltDE and ATCC 27126. Strain SN2's genome differs from that of the other two strains in: size, average nucleotide identity value, tRNA genes, noncoding RNAs, dioxygenase gene content, signal transduction genes, and the degree to which genes collected during the Global Ocean Sampling project are represented. Patterns in genetic characteristics (e.g., GC content, GC skew, Karlin signature, CRISPR gene homology) indicate that strain SN2's genome architecture has been altered via horizontal gene transfer (HGT). Experiments proved that strain SN2 was far more cold tolerant, especially at 5°C, than the other two strains. Consistent with the HGT hypothesis, a total of 15 genomic islands in strain SN2 likely confer ecological fitness traits (especially membrane transport, aromatic hydrocarbon metabolism, and fatty acid biosynthesis) specific to the adaptation of strain SN2 to its seasonally cold sea-tidal flat habitat. PMID:22563400

Impact of pe_pgrs33 Gene Polymorphisms on Mycobacterium tuberculosis Infection and Pathogenesis.

PubMed

Camassa, Serena; Palucci, Ivana; Iantomasi, Raffaella; Cubeddu, Tiziana; Minerva, Mariachiara; De Maio, Flavio; Jouny, Samuel; Petruccioli, Elisa; Goletti, Delia; Ria, Francesco; Sali, Michela; Sanguinetti, Maurizio; Manganelli, Riccardo; Rocca, Stefano; Brodin, Priscille; Delogu, Giovanni

2017-01-01

PE_PGRS33 is a surface-exposed protein of Mycobacterium tuberculosis ( Mtb ) which exerts its role in macrophages entry and immunomodulation. In this study, we aimed to investigate the polymorphisms in the pe_pgrs33 gene of Mtb clinical isolates and evaluate their impact on protein functions. We sequenced pe_pgrs33 in a collection of 135 clinical strains, genotyped by 15-loci MIRU-VNTR and spoligotyping and belonging to the Mtb complex (MTBC). Overall, an association between pe_pgrs33 alleles and MTBC genotypes was observed and a dN/dS ratio of 0.64 was obtained, suggesting that a purifying selective pressure is acting on pe_pgrs33 against deleterious SNPs. Among a total of 19 pe_pgrs33 alleles identified in this study, 5 were cloned and used to complement the pe_pgrs33 knock-out mutant strain of Mtb H37Rv ( Mtb Δ33) to assess the functional impact of the respective polymorphisms in in vitro infections of primary macrophages. In human monocyte-derived macrophages (MDMs) infection, large in-frame and frameshift mutations were unable to restore the phenotype of Mtb H37Rv, impairing the cell entry capacity of Mtb , but neither its intracellular replication rate nor its immunomodulatory properties. In vivo studies performed in the murine model of tuberculosis (TB) demonstrated that the Mtb Δ33 mutant strain was not impaired in the ability to infect and replicate in the lung tissue compared to the parental strain. Interestingly, Mtb Δ33 showed an enhanced virulence during the chronic steps of infection compared to Mtb H37Rv. Similarly, the complementation of Mtb Δ33 with a frameshift allele also resulted in a Mtb strain capable of causing a surprisingly enhanced tissue damage in murine lungs, during the chronic steps of infection. Together, these results further support the role of PE_PGRS33 in the pathogenesis and virulence of Mtb .

Metabolic functions of Pseudomonas fluorescens strains from Populus deltoides depend on rhizosphere or endosphere isolation compartment

DOE PAGES

Timm, Collin M.; Campbell, Alicia G.; Utturkar, Sagar M.; ...

2015-10-14

The bacterial microbiota of plants is diverse, with ~1000s of operational taxonomic units (OTUs) associated with any individual plant. In this work we investigate how 19 sequenced Pseudomonas fluorescens strains representing a single OTU isolated from Populus deltoides rhizosphere and endosphere differ using phenotypic analysis, comparative genomics, and metabolic models. While no traits were exclusive to either endosphere or rhizosphere P. fluorescens isolates, multiple pathways relevant for bacterial-plant interactions are enriched in endosphere isolate genomes and growth phenotypes such as phosphate solubilization, protease activity, denitrification and root growth promotion are biased towards endosphere isolates. Endosphere isolates have more metabolic pathwaysmore » for plant signaling compounds and an increased metabolic range that includes utilization of energy rich nucleotides and sugars, consistent with endosphere colonization. Rhizosphere P. fluorescens have fewer pathways important for bacterial-plant interactions but show metabolic bias towards chemical substrates often found in root exudates. This work reveals the diverse functions that may contribute to colonization of the endosphere by bacteria that are enriched in event he most closely related isolates.« less

Structure-In Vitro Activity Relationships of Pentamidine Analogues and Dication-Substituted Bis-Benzimidazoles as New Antifungal Agents

PubMed Central

Del Poeta, Maurizio; Schell, Wiley A.; Dykstra, Christine C.; Jones, Susan; Tidwell, Richard R.; Czarny, Agnieszka; Bajic, Miroslav; Bajic, Marina; Kumar, Arvind; Boykin, David; Perfect, John R.

1998-01-01

Twenty analogues of pentamidine, 7 primary metabolites of pentamidine, and 30 dicationic substituted bis-benzimidazoles were screened for their inhibitory and fungicidal activities against Candida albicans and Cryptococcus neoformans. A majority of the compounds had MICs at which 80% of the strains were inhibited (MIC80s) comparable to those of amphotericin B and fluconazole. Unlike fluconazole, many of these compounds were found to have potent fungicidal activity. The most potent compound against C. albicans had an MIC80 of ≤0.09 μg/ml, and the most potent compound against C. neoformans had an MIC80 of 0.19 μg/ml. Selected compounds were also found to be active against Aspergillus fumigatus, Fusarium solani, Candida species other than C. albicans, and fluconazole-resistant strains of C. albicans and C. neoformans. It is clear from the data presented here that further studies on the structure-activity relationships, mechanisms of action and toxicities, and in vivo efficacies of these compounds are warranted to determine their clinical potential. PMID:9756747

Metabolic functions of Pseudomonas fluorescens strains from Populus deltoides depend on rhizosphere or endosphere isolation compartment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Timm, Collin M.; Campbell, Alicia G.; Utturkar, Sagar M.

The bacterial microbiota of plants is diverse, with ~1000s of operational taxonomic units (OTUs) associated with any individual plant. In this work we investigate how 19 sequenced Pseudomonas fluorescens strains representing a single OTU isolated from Populus deltoides rhizosphere and endosphere differ using phenotypic analysis, comparative genomics, and metabolic models. While no traits were exclusive to either endosphere or rhizosphere P. fluorescens isolates, multiple pathways relevant for bacterial-plant interactions are enriched in endosphere isolate genomes and growth phenotypes such as phosphate solubilization, protease activity, denitrification and root growth promotion are biased towards endosphere isolates. Endosphere isolates have more metabolic pathwaysmore » for plant signaling compounds and an increased metabolic range that includes utilization of energy rich nucleotides and sugars, consistent with endosphere colonization. Rhizosphere P. fluorescens have fewer pathways important for bacterial-plant interactions but show metabolic bias towards chemical substrates often found in root exudates. This work reveals the diverse functions that may contribute to colonization of the endosphere by bacteria that are enriched in event he most closely related isolates.« less

Expression of cytokeratins in Helicobacter pylori –associated chronic gastritis of adult patients infected with cagA+ strains: An immunohistochemical study

PubMed Central

Todorovic, Vera; Sokic-Milutinovic, Aleksandra; Drndarevic, Neda; Micev, Marjan; Mitrovic, Olivera; Nikolic, Ivan; Wex, Thomas; Milosavljevic, Tomica; Malfertheiner, Peter

2006-01-01

AIM: To investigate the expression of different cytokeratins (CKs) in gastric epithelium of adult patients with chronic gastritis infected with Helicobacter pylori (H pylori) cagA+ strains. METHODS: The expression of CK 7, 8, 18, 19 and 20 was studied immunohistochemically in antral gastric biopsies of 84 patients. All the CKs were immunostained in cagA+H pylori gastritis (57 cases), non-H pylori gastritis (17 cases) and normal gastric mucosa (10 cases). RESULTS: In cagA+ H pylori gastritis, CK8 was expressed comparably to the normal antral mucosa from surface epithelium to deep glands. Distribution of CK18 and CK 19 was unchanged, i.e. transmucosal, but intensity of the expression was different in foveolar region in comparison to normal gastric mucosa. Cytokeratin 18 immunoreactivity was significantly higher in the foveolar epithelium of H pylori-positive gastritis compared to both H pylori-negative gastritis and controls. On the contrary, decrease in CK19 immunoreactivity occurred in foveolar epithelium of H pylori-positive gastritis. In both normal and inflamed antral mucosa without H pylori infection, CK20 was expressed strongly/moderately and homogenously in surface epithelium and upper foveolar region, but in H pylori -induced gastritis significant decrease of expression in foveolar region was noted. Generally, in both normal antral mucosa and H pylori-negative gastritis, expression of CK7 was not observed, while in about half cagA+ H pylori-infected patients, moderate focal CK7 immunoreactivity of the neck and coiled gland areas was registered, especially in areas with more severe inflammatory infiltrate. CONCLUSION: Alterations in expression of CK 7, 18, 19 and 20 together with normal expression of CK8 occur in antral mucosa of H pylori-associated chronic gastritis in adult patients infected with cagA+ strains. Alterations in different cytokeratins expression might contribute to weakening of epithelial tight junctions observed in H pylori-infected gastric mucosa. PMID:16609992

Enological characterization of Spanish Saccharomyces kudriavzevii strains, one of the closest relatives to parental strains of winemaking and brewing Saccharomyces cerevisiae × S. kudriavzevii hybrids.

PubMed

Peris, D; Pérez-Través, L; Belloch, C; Querol, A

2016-02-01

Wine fermentation and innovation have focused mostly on Saccharomyces cerevisiae strains. However, recent studies have shown that other Saccharomyces species can also be involved in wine fermentation or are useful for wine bouquet, such as Saccharomyces uvarum and Saccharomyces paradoxus. Many interspecies hybrids have also been isolated from wine fermentation, such as S. cerevisiae × Saccharomyces kudriavzevii hybrids. In this study, we explored the genetic diversity and fermentation performance of Spanish S. kudriavzevii strains, which we compared to other S. kudriavzevii strains. Fermentations of red and white grape musts were performed, and the phenotypic differences between Spanish S. kudriavzevii strains under different temperature conditions were examined. An ANOVA analysis suggested striking similarity between strains for glycerol and ethanol production, although a high diversity of aromatic profiles among fermentations was found. The sources of these phenotypic differences are not well understood and require further investigation. Although the Spanish S. kudriavzevii strains showed desirable properties, particularly must fermentations, the quality of their wines was no better than those produced with a commercial S. cerevisiae. We suggest hybridization or directed evolution as methods to improve and innovate wine. Copyright © 2015 Elsevier Ltd. All rights reserved.

Intensified colonisation screening according to the recommendations of the German Commission for Hospital Hygiene and Infectious Diseases Prevention (KRINKO): identification and containment of a Serratia marcescens outbreak in the neonatal intensive care unit, Jena, Germany, 2013-2014.

PubMed

Dawczynski, Kristin; Proquitté, Hans; Roedel, Jürgen; Edel, Brigit; Pfeifer, Yvonne; Hoyer, Heike; Dobermann, Helke; Hagel, Stefan; Pletz, Mathias W

2016-12-01

In 2013, the German Commission for Hospital Hygiene and Infectious Disease Prevention (KRINKO) stated that extending weekly colonisation screening from very low birth weight (VLBW) infants (<1500 g) to all patients in the Neonatal Intensive Care Unit (NICU) might be useful. After implementing this recommendation, we detected a previously unnoticed cluster of Serratia marcescens. Strains were typed by Pulsed Field Gel Electrophoresis (PFGE). Over 6 months, 19 out of 159 infants acquired S. marcescens. Twelve of the nineteen patients with S. marcescens were non-VLBW infants, and they were colonised significantly earlier than were VLBW infants (median 17 vs. 28 days; p < 0.01). Molecular typing revealed a polyclonal outbreak with multiple strain types leading to one or two transmissions each and a dominating outbreak strains being involved in an explosive outbreak involving eight neonates. The revised KRINKO recommendation may help identify unnoticed outbreaks. Colonised non-VLBW patients may be an underestimated source of S. marcescens.

Development of a rapid recombinase polymerase amplification assay for the detection of Streptococcus pneumoniae in whole blood.

PubMed

Clancy, Eoin; Higgins, Owen; Forrest, Matthew S; Boo, Teck Wee; Cormican, Martin; Barry, Thomas; Piepenburg, Olaf; Smith, Terry J

2015-10-29

Streptococcus pneumoniae is an important cause of microbial disease in humans. The introduction of multivalent vaccines has coincided with a dramatic decrease in the number of pneumococcal-related deaths. In spite of this, at a global level, pneumococcal infection remains an important cause of death among children under 5 years of age and in adults 65 years of age or older. In order to properly manage patients and control the spread of infection, a rapid and highly sensitive diagnostic method is needed for routine implementation, especially in resource-limited regions where pneumococcal disease is most prevalent. Using the gene encoding leader peptidase A as a molecular diagnostics target, a real-time RPA assay was designed and optimised for the detection of S. pneumoniae in whole blood. The performance of the assay was compared to real-time PCR in terms of its analytical limit of detection and specificity. The inhibitory effect of human genomic DNA on amplification was investigated. The potential clinical utility of the assay was investigated using a small number of clinical samples. The RPA assay has a limit of detection equivalent to PCR (4.0 and 5.1 genome equivalents per reaction, respectively) and was capable of detecting the equivalent of <1 colony forming unit of S. pneumoniae when spiked into human whole blood. The RPA assay was 100 % inclusive (38/38 laboratory reference strains and 19/19 invasive clinical isolates) and 100 % exclusive; differentiating strains of S. pneumoniae species from other viridans group streptococci, including S. pseudopneumoniae. When applied to the analysis of a small number (n = 11) of clinical samples (blood culture positive for S. pneumoniae), the RPA assay was demonstrated to be both rapid and sensitive. The RPA assay developed in this work is shown to be as sensitive and as specific as PCR. In terms of reaction kinetics, the RPA assay is shown to exceed those of the PCR, with the RPA running to completion in 20 minutes and capable generating a positive signal in as little as 6 minutes. This work represents a potentially suitable assay for application in point-of-care settings.

Comparative c-type cytochrome expression analysis in Shewanella oneidensis strain MR-1 and Anaeromyxobacter dehalogenans strain 2CP-C grown with soluble and insoluble oxidised metal electron acceptors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nissen, Silke; Liu, Xiaoxin; Chourey, Karuna

2012-01-01

The genomes of Shewanella oneidensis strain MR-1 and Anaeromyxobacter dehalogenans strain 2CP-C encode 40 and 69 putative c-type cytochrome genes, respectively. Deletion mutant and biochemical studies have assigned specific functions to a few c-type cytochromes involved in electron transfer to oxidised metals in Shewanella oneidensis strain MR-1. Although promising, the genetic approach is limited to gene deletions that produce a distinct phenotype, and organism for which a genetic system is available. To more comprehensively investigate and compare c-type cytochrome expression in Shewanella oneidensis strain MR-1 and Anaeromyxobacter dehalogenans strain 2CP-C, proteomic measurements were used to characterise lysates of cells grownmore » with soluble Fe(III) (as ferric citrate) and insoluble Mn(IV) (as MnO2) as electron acceptors. Strain MR-1 expressed 19 and 20, and strain 2CP-C expressed 27 and 25 c-type cytochromes when grown with Fe(III) and Mn(IV), respectively. The majority of c-type cytochromes (77% for strain MR-1 and 63% for strain 2CP-C) were expressed under both growth conditions; however, the analysis also revealed unique c-type cytochromes that were specifically expressed in cells grown with soluble Fe(III) or insoluble Mn(IV). Proteomic characterisation proved to be a promising approach for determining the c-type cytochrome complement expressed under different growth conditions, and will help elucidating the specific functions of more c-type cytochromes that are the basis for Shewanella and Anaeromyxobacter respiratory versatility.« less

Evidence of metabolic mechanisms playing a role in multiple insecticides resistance in Anopheles stephensi populations from Afghanistan.

PubMed

Safi, Noor Halim Zahid; Ahmadi, Abdul Ali; Nahzat, Sami; Ziapour, Seyyed Payman; Nikookar, Seyed Hassan; Fazeli-Dinan, Mahmoud; Enayati, Ahmadali; Hemingway, Janet

2017-03-03

Malaria is endemic in most parts of Afghanistan and insecticide-based vector control measures are central in controlling the disease. Insecticide resistance in the main malaria vector Anopheles stephensi from Afghanistan is increasing and attempts should be made to determine the underlying resistance mechanisms for its adequate management. The contents of cytochrome P450s, esterases, glutathione S-transferases (GSTs) and acetylcholine esterase (AChE) activities were measured in the Kunar and Nangarhar populations of An. stephensi from Afghanistan and the results were compared with those of the susceptible Beech strain using the World Health Organization approved biochemical assay methods for adult mosquitoes. The cytochrome P450s enzyme ratios were 2.23- and 2.54-fold in the Kunar and Nangarhar populations compared with the susceptible Beech strain. The enzyme ratios for esterases with alpha-naphthyl acetate were 1.45 and 2.11 and with beta-naphthyl acetate were 1.62 and 1.85 in the Kunar and Nangarhar populations respectively compared with the susceptible Beech strain. Esterase ratios with para-nitrophenyl acetate (pNPA) were 1.61 and 1.75 in the Kunar and Nangarhar populations compared with the susceptible Beech strain. The GSTs enzyme ratios were 1.33 and 1.8 in the Kunar and Nangarhar populations compared with the susceptible Beech strain. The inhibition of AChE was 70.9 in the susceptible Beech strain, and 56.7 and 51.5 in the Kunar and Nangarhar populations. The differences between all values of the enzymes activities/contents and AChE inhibition rates in the Kunar and Nangarhar populations were statistically significant when compared with those of the susceptible Beech strain. Based on the results, the reported resistance to pyrethroid and organophosphate insecticides, and tolerance to bendiocarb in the Kunar and Nangarhar populations of An. stephensi from Afghanistan are likely to be caused by a range of metabolic mechanisms, including esterases, P450s and GSTs combined with target site insensitivity in AChE.

Electroantennogram Responses to Plant Volatiles Associated with Fenvalerate Resistance in the Diamondback Moth, Plutella xylostella (Lepidoptera: Plutellidae).

PubMed

Houjun, Tian; Lin, Shuo; Chen, Yong; Chen, Yixin; Zhao, Jianwei; Gu, Xiaojun; Wei, Hui

2018-05-28

The diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is the main destructive insect pest of brassica vegetables around the world, and has developed resistance to numerous insecticides. Although host plant volatiles are important in pest control, the mechanism of low-level insecticide resistance in P. xylostella due to plant volatiles has not been examined. Here, electroantennograms (EAGs) were used to compare the responses of adult male and female DBMs of a susceptible strain (S-strain) and a derived resistant strain, Fen-R-strain (6.52-fold more resistant than the S-strain), to different concentrations of nine plant volatiles. We found significantly different relative EAG responses between S-strain and Fen-R-strain males to different concentrations of methyl jasmonate, methyl salicylate, and octanal. The relative EAG responses of S-strain and Fen-R-strain females to different concentrations of β-myrcene, methyl jasmonate, methyl salicylate, and allyl isothiocyanate were significantly different. Fen-R-strain females showed lower EAG responses to most of the tested plant volatiles (at concentrations of 1:10) than males, except for allyl isothiocyanate. A larger difference in relative EAG response to α-farnesene and β-myrcene was found between S-strain and Fen-R-strain females than between males of the two strains. A larger difference in relative EAG response to octanal, nonanal, and octan-1-ol was found between S-strain and Fen-R-strain males than between females of the two strains. These results illustrate the relationship between the function of plant volatiles and resistance in an insect pest species, and provide a scientific basis for resistance evolutionary theory in pest management research.

High-Pressure Inactivation of Rotaviruses: Role of Treatment Temperature and Strain Diversity in Virus Inactivation

PubMed Central

Araud, Elbashir; DiCaprio, Erin; Yang, Zhihong; Li, Xinhui; Lou, Fangfei; Hughes, John H.; Chen, Haiqiang

2015-01-01

Rotavirus (RV) is the major etiological agent of acute gastroenteritis in infants worldwide. Although high-pressure processing (HPP) is a popular method to inactivate enteric pathogens in food, the sensitivity of different virus strains within same species and serotype to HPP is variable. This study aimed to compare the barosensitivities of seven RV strains derived from four serotypes (serotype G1, strains Wa, Ku, and K8; serotype G2, strain S2; serotype G3, strains SA-11 and YO; and serotype G4, strain ST3) following high-pressure treatment. RV strains showed various responses to HPP based on the initial temperature and had different inactivation profiles. Ku, K8, S2, SA-11, YO, and ST3 showed enhanced inactivation at 4°C compared to 20°C. In contrast, strain Wa was not significantly impacted by the initial treatment temperature. Within serotype G1, strain Wa was significantly (P < 0.05) more resistant to HPP than strains Ku and K8. Overall, the resistance of the human RV strains to HPP at 4°C can be ranked as Wa > Ku = K8 > S2 > YO > ST3, and in terms of serotype the ranking is G1 > G2 > G3 > G4. In addition, pressure treatment of 400 MPa for 2 min was sufficient to eliminate the Wa strain, the most pressure-resistant RV, from oyster tissues. HPP disrupted virion structure but did not degrade viral protein or RNA, providing insight into the mechanism of viral inactivation by HPP. In conclusion, HPP is capable of inactivating RV at commercially acceptable pressures, and the efficacy of inactivation is strain dependent. PMID:26187961

Simultaneous isolation of emm89-type Streptococcus pyogenes strains with a wild-type or mutated covS gene from a single streptococcal toxic shock syndrome patient.

PubMed

Masuno, Katsuaki; Okada, Ryo; Zhang, Yan; Isaka, Masanori; Tatsuno, Ichiro; Shibata, Shinichiro; Hasegawa, Tadao

2014-04-01

Streptococcal toxic shock syndrome (STSS) is a re-emerging infectious disease in many developed countries. Recent studies have suggested that mutations in CovRS, a two-component regulatory system in Streptococcus pyogenes, play important roles in the pathogenesis of STSS. However, in vivo evidence of the significance of CovRS in human infections has not been fully demonstrated. We investigated five S. pyogenes strains isolated simultaneously from the pharynx, sputum, knee joint, cerebrospinal fluid and blood of a single STSS patient. All were emm89-type strains, and multilocus sequence typing (MLST) analysis revealed that the strains of pharynx and blood were isogenic. The growth rates of the strains from pharynx and sputum were faster than those of the other strains. Protein profiles of the culture supernatants of strains from the pharynx and sputum were also different from those of the other strains. Sequence analyses revealed that strains from the knee joint, cerebrospinal fluid and blood contained a single nucleotide difference in the covS coding region, resulting in one amino acid change, compared with the other strains. Introduction of a plasmid containing the covS gene from the pharynx strain to the blood strain increased the production of SpeB protein. This suggests that the one amino acid alteration in CovS was relevant to pathogenesis. This report supports the idea that mutated CovS plays important roles in vivo in the dissemination of S. pyogenes from the upper respiratory tract of human to aseptic tissues such as blood and cerebrospinal fluid.

Comparison of four molecular methods to type Salmonella Enteritidis strains.

PubMed

Campioni, Fábio; Pitondo-Silva, André; Bergamini, Alzira M M; Falcão, Juliana P

2015-05-01

This study compared the pulsed-field gel electrophoresis (PFGE), enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR), multilocus variable-number of tanden-repeat analysis (MLVA), and multilocus sequence typing (MLST) methods for typing 188 Salmonella Enteritidis strains from different sources isolated over a 24-year period in Brazil. PFGE and ERIC-PCR were more efficient than MLVA for subtyping the strains. However, MLVA provided additional epidemiological information for those strains. In addition, MLST showed the Brazilian strains as belonging to the main clonal complex of S. Enteritidis, CC11, and provided the first report of two new STs in the S. enterica database but could not properly subtype the strains. Our results showed that the use of PFGE or ERIC-PCR together with MLVA is suitable to efficiently subtype S. Enteritidis strains and provide important epidemiological information. © 2015 APMIS. Published by John Wiley & Sons Ltd.

Quantifying Variability in Growth and Thermal Inactivation Kinetics of Lactobacillus plantarum.

PubMed

Aryani, D C; den Besten, H M W; Zwietering, M H

2016-08-15

The presence and growth of spoilage organisms in food might affect the shelf life. In this study, the effects of experimental, reproduction, and strain variabilities were quantified with respect to growth and thermal inactivation using 20 Lactobacillus plantarum strains. Also, the effect of growth history on thermal resistance was quantified. The strain variability in μmax was similar (P > 0.05) to reproduction variability as a function of pH, aw, and temperature, while being around half of the reproduction variability (P < 0.05) as a function of undissociated lactic acid concentration [HLa]. The cardinal growth parameters were estimated for the L. plantarum strains, and the pHmin was between 3.2 and 3.5, the aw,min was between 0.936 and 0.953, the [HLamax], at pH 4.5, was between 29 and 38 mM, and the Tmin was between 3.4 and 8.3°C. The average D values ranged from 0.80 min to 19 min at 55°C, 0.22 to 3.9 min at 58°C, 3.1 to 45 s at 60°C, and 1.8 to 19 s at 63°C. In contrast to growth, the strain variability in thermal resistance was on average six times higher than the reproduction variability and more than ten times higher than the experimental variability. The strain variability was also 1.8 times higher (P < 0.05) than the effect of growth history. The combined effects of strain variability and growth history on D value explained all of the variability as found in the literature, although with bias. Based on an illustrative milk-processing chain, strain variability caused ∼2-log10 differences in growth between the most and least robust strains and >10-log10 differences after thermal treatment. Accurate control and realistic prediction of shelf life is complicated by the natural diversity among microbial strains, and limited information on microbiological variability is available for spoilage microorganisms. Therefore, the objectives of the present study were to quantify strain variability, reproduction (biological) variability, and experimental variability with respect to the growth and thermal inactivation kinetics of Lactobacillus plantarum and to quantify the variability in thermal resistance attributed to growth history. The quantitative knowledge obtained on experimental, reproduction, and strain variabilities can be used to improve experimental designs and to adequately select strains for challenge growth and inactivation tests. Moreover, the integration of strain variability in prediction of microbial growth and inactivation kinetics will result in more realistic predictions of L. plantarum dynamics along the food production chain. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Genomic Evolution of Saccharomyces cerevisiae under Chinese Rice Wine Fermentation

PubMed Central

Li, Yudong; Zhang, Weiping; Zheng, Daoqiong; Zhou, Zhan; Yu, Wenwen; Zhang, Lei; Feng, Lifang; Liang, Xinle; Guan, Wenjun; Zhou, Jingwen; Chen, Jian; Lin, Zhenguo

2014-01-01

Rice wine fermentation represents a unique environment for the evolution of the budding yeast, Saccharomyces cerevisiae. To understand how the selection pressure shaped the yeast genome and gene regulation, we determined the genome sequence and transcriptome of a S. cerevisiae strain YHJ7 isolated from Chinese rice wine (Huangjiu), a popular traditional alcoholic beverage in China. By comparing the genome of YHJ7 to the lab strain S288c, a Japanese sake strain K7, and a Chinese industrial bioethanol strain YJSH1, we identified many genomic sequence and structural variations in YHJ7, which are mainly located in subtelomeric regions, suggesting that these regions play an important role in genomic evolution between strains. In addition, our comparative transcriptome analysis between YHJ7 and S288c revealed a set of differentially expressed genes, including those involved in glucose transport (e.g., HXT2, HXT7) and oxidoredutase activity (e.g., AAD10, ADH7). Interestingly, many of these genomic and transcriptional variations are directly or indirectly associated with the adaptation of YHJ7 strain to its specific niches. Our molecular evolution analysis suggested that Japanese sake strains (K7/UC5) were derived from Chinese rice wine strains (YHJ7) at least approximately 2,300 years ago, providing the first molecular evidence elucidating the origin of Japanese sake strains. Our results depict interesting insights regarding the evolution of yeast during rice wine fermentation, and provided a valuable resource for genetic engineering to improve industrial wine-making strains. PMID:25212861

Carriage and invasive isolates of Streptococcus pneumoniae in Caracas, Venezuela: the relative invasiveness of serotypes and vaccine coverage.

PubMed

Rivera-Olivero, I A; del Nogal, B; Sisco, M C; Bogaert, D; Hermans, P W M; de Waard, J H

2011-12-01

The introduction of a pneumococcal conjugate vaccine in Venezuela needs previous studies to assess vaccine efficiency. We conducted a survey of nasopharyngeal pneumococcal carriage in urban children in Caracas and studied the distribution of serotypes. We compared these data with survey data available for invasive strains isolated in the same area and in the same time period. An overall pneumococcal carriage rate of 27% was observed. The most predominant capsular serotypes among carriage isolates were 6B (29%), 19A (13.8%), 23F (10%), 14 (8.3%), 6A (8.3%) and 15B/C (3.3%) and among invasive isolates 6B (25%), 14 (15%), and 19A, 6A, 7F, and 18 (7.5% each). The serotypes/groups 1, 5, 7F and 18, jointly covering 30% of the invasive strains, represented less than 0.7% of the carrier strains. The theoretical coverage of the pneumococcal conjugate vaccine PCV13 for carriage and invasive strains was calculated to be 74% and 90%, respectively. Our study demonstrates important differences for the serotype distribution in disease and carriage isolates and provides a key baseline for future studies addressing the prevalence and replacement of invasive and carriage serotypes after the introduction of the PCV 13 vaccine in Venezuela in the year 2010.

Mycobacterium tuberculosis strains exhibit differential and strain-specific molecular signatures in pulmonary epithelial cells.

PubMed

Mvubu, Nontobeko Eunice; Pillay, Balakrishna; Gamieldien, Junaid; Bishai, William; Pillay, Manormoney

2016-12-01

Although pulmonary epithelial cells are integral to innate and adaptive immune responses during Mycobacterium tuberculosis infection, global transcriptomic changes in these cells remain largely unknown. Changes in gene expression induced in pulmonary epithelial cells infected with M. tuberculosis F15/LAM4/KZN, F11, F28, Beijing and Unique genotypes were investigated by RNA sequencing (RNA-Seq). The Illumina HiSeq 2000 platform generated 50 bp reads that were mapped to the human genome (Hg19) using Tophat (2.0.10). Differential gene expression induced by the different strains in infected relative to the uninfected cells was quantified and compared using Cufflinks (2.1.0) and MeV (4.0.9), respectively. Gene expression varied among the strains with the total number of genes as follows: F15/LAM4/KZN (1187), Beijing (1252), F11 (1639), F28 (870), Unique (886) and H37Rv (1179). A subset of 292 genes was commonly induced by all strains, where 52 genes were down-regulated while 240 genes were up-regulated. Differentially expressed genes were compared among the strains and the number of induced strain-specific gene signatures were as follows: F15/LAM4/KZN (138), Beijing (52), F11 (255), F28 (55), Unique (186) and H37Rv (125). Strain-specific molecular gene signatures associated with functional pathways were observed only for the Unique and H37Rv strains while certain biological functions may be associated with other strain signatures. This study demonstrated that strains of M. tuberculosis induce differential gene expression and strain-specific molecular signatures in pulmonary epithelial cells. Specific signatures induced by clinical strains of M. tuberculosis can be further explored for novel host-associated biomarkers and adjunctive immunotherapies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Transcriptional analysis of four family 4 P450s in a Puerto Rico strain of Aedes aegypti (Diptera: Culicidae) compared with an Orlando strain and their possible functional roles in permethrin resistance.

PubMed

Reid, William R; Thornton, Anne; Pridgeon, Julia W; Becnel, James J; Tang, Fang; Estep, Alden; Clark, Gary G; Allan, Sandra; Liu, Nannan

2014-05-01

A field strain of Aedes aegypti (L.) was collected from Puerto Rico in October 2008. Based on LD50 values by topical application, the Puerto Rico strain was 73-fold resistant to permethrin compared with a susceptible Orlando strain. In the presence of piperonyl butoxide, the resistance of Puerto Rico strain of Ae. aegypti was reduced to 15-fold, suggesting that cytochrome P450-mediated detoxification is involved in the resistance of the Puerto Rico strain to permethrin. To determine the cytochrome P450s that might play a role in the resistance to permethrin, the transcriptional levels of 164 cytochrome P450 genes in the Puerto Rico strain were compared with that in the Orlando strain. Of the 164 cytochrome P450s, 33 were significantly (P < 0.05) up-regulated, including cytochrome P450s in families four, six, and nine. Multiple studies have investigated the functionality of family six and nine cytochrome P450s, therefore, we focused on the up-regulated family 4 cytochrome P450s. To determine whether up-regulation of the four cytochrome P450s had any functional role in permethrin resistance, transgenic Drosophila melanogaster Meigen lines overexpressing the four family 4 P450 genes were generated, and their ability to survive exposure to permethrin was evaluated. When exposed to 5 microg per vial permethrin, transgenic D. melanogaster expressing CYP4D24, CYP4H29, CYP4J15v1, and CYP4H33 had a survival rate of 60.0 +/- 6.7, 29.0 +/- 4.4, 64.4 +/- 9.7, and 11.0 +/- 4.4%, respectively. However, none of the control flies survived the permethrin exposure at the same concentration. Similarly, none of the transgenic D. melanogaster expressing CYP4J15v1 or CYP4H33 ?5 survived when they were exposed to permethrin at 10 microg per vial. However, transgenic D. melanogaster expressing CYP4D24 and CYP4H29 had a survival rate of 37.8 +/- 4.4 and 2.2 +/- 2.2%, respectively. Taken together, our results suggest that CYP4D24 might play an important role in cytochrome P450-mediated resistance to permethrin.

Measurement and Analysis of Ultra-Thin Austenitic Stainless Steel Sheet under Biaxial Tensile Loading and In-Plane Reverse Loading

NASA Astrophysics Data System (ADS)

Murakoso, Satoko; Kuwabara, Toshihiko

Biaxial tensile tests of austenitic stainless steel sheet (SUS304) 0.2mm thick have been carried out using cruciform specimens. The specimens are loaded under linear stress paths in a servo-controlled biaxial tensile testing machine. Plastic orthotropy remained coaxial with the principal stresses throughout every experiment. The successive contours of plastic work in biaxial stress space changed their shapes progressively, exemplifying differential work hardening. The geometry of the entire family of the work contours and the directions of plastic strain rates have been precisely measured and compared with those calculated using conventional yield functions. Yld2000-2d [Barlat, F., Brem, J.C., Yoon, J.W., Chung, K., Dick, R.E., Lege, D.J., Pourboghrat, F., Choi, S.H. and Chu, E., International Journal of Plasticity, Vol. 19, (2003), pp. 1297-1319.] with an exponent of 6 was capable of reproducing the general trends of the work contours and the directions of plastic strain rates with good accuracy. Furthermore, in order to quantitatively evaluate the Bauschinger effect of the test material, in-plane tension/compression tests are conducted. It was found that the non-dimensional (σ /σu) - Δɛ /(σu/ E) curves measured during unloading almost fall on a single curve and are not affected by the amount of pre-strain, where σ is the current stress during unloading, σu is the stress immediately before unloading, Δɛ (< 0) is the total strain increment during unloading.

Tenacibaculum caenipelagi sp. nov., a member of the family Flavobacteriaceae isolated from tidal flat sediment.

PubMed

Park, Sooyeon; Yoon, Jung-Hoon

2013-08-01

A Gram-stain-negative, non-spore-forming, aerobic, non-flagellated, gliding and rod-shaped bacterial strain, designated HJ-26M(T), was isolated from a tidal flat sediment in the Korean peninsula. It grew optimally at 25-30 °C, at pH 7.0-8.0 and in the presence of 2 % (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that the strain fell within the clade comprising Tenacibaculum species, clustering coherently with the type strains of Tenacibaculum lutimaris and Tenacibaculum aestuarii. Strain HJ-26M(T) exhibited the highest 16S rRNA gene sequence similarity values of 98.4 and 98.2 % to T. lutimaris TF-26(T) and T. aestuarii SMK-4(T), respectively, and of 94.9-97.4 % to the type strains of the other Tenacibaculum species. Strain HJ-26M(T) contained MK-6 as the predominant menaquinone and iso-C15:0 and iso-C17:0 3-OH as the major fatty acids. The DNA G+C content of strain HJ-26M(T) was 34.5 mol% and its mean DNA-DNA relatedness values with the type strains of T. lutimaris and T. aestuarii were 19 and 23 %, respectively. Differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain HJ-26M(T) is separate from other Tenacibaculum species. On the basis of the data presented, strain HJ-26M(T) is considered to represent a novel species of the genus Tenacibaculum, for which the name Tenacibaculum caenipelagi sp. nov. is proposed. The type strain is HJ-26M(T) (= KCTC 32323(T) = CECT 8283(T)).

Streptomyces xiangtanensis sp. nov., isolated from a manganese-contaminated soil.

PubMed

Mo, Ping; Yu, Yi-Zun; Zhao, Jia-Rong; Gao, Jian

2017-03-01

An actinomycete strain, designated strain LUSFXJ T , was isolated from a soil sample obtained near the Xiangtan Manganese Mine, Central-South China and characterised using a polyphasic taxonomic approach. The 16S rRNA gene sequence-based phylogenetic analysis indicated that this strain belongs to the genus Streptomyces. The DNA-DNA relatedness between this strain and two closely related type strains, Streptomyces echinatus CGMCC 4.1642 T and Streptomyces lanatus CGMCC 4.137 T , were 28.7 ± 0.4 and 19.9 ± 2.0%, respectively, values which are far lower than the 70% threshold for the delineation of a novel prokaryotic species. The DNA G+C content of strain LUSFXJ T is 75.0 mol%. Chemotaxonomic analysis revealed that the menaquinones of strain LUSFXJ T are MK-9(H 6 ), MK-9(H 8 ), MK-9(H 2 ) and MK-8(H 8 ). The polar lipid profile of strain LUSFXJ T was found to contain diphosphatidylglycerol and an unidentified polar lipid. The major cellular fatty acids were identified as iso-C 15:0 , anteiso-C 15:0 , iso-C 16:0 , C 16:0 and Summed feature 3. Strain LUSFXJ T was found to contain meso-diaminopimelic acid as the diagnostic cell wall diamino acid and the whole cell hydrolysates were found to be rich in ribose, mannose and glucose. Based on phenotypic, phylogenetic and chemotaxonomic characteristics, it is concluded that strain LUSFXJ T represents a novel species of the genus Streptomyces, for which the name S. xiangtanensis sp. nov. is proposed. The type strain is LUSFXJ T (=GDMCC 4.133 T  = KCTC 39829 T ).

Evaluation and Comparison of the Pathogenicity and Host Immune Responses Induced by a G2b Taiwan Porcine Epidemic Diarrhea Virus (Strain Pintung 52) and Its Highly Cell-Culture Passaged Strain in Conventional 5-Week-Old Pigs.

PubMed

Chang, Yen-Chen; Kao, Chi-Fei; Chang, Chia-Yu; Jeng, Chian-Ren; Tsai, Pei-Shiue; Pang, Victor Fei; Chiou, Hue-Ying; Peng, Ju-Yi; Cheng, Ivan-Chen; Chang, Hui-Wen

2017-05-19

A genogroup 2b (G2b) porcine epidemic diarrhea virus (PEDV) Taiwan Pintung 52 (PEDVPT) strain was isolated in 2014. The pathogenicity and host antibody responses elicited by low-passage (passage 5; PEDVPT-P5) and high-passage (passage 96; PEDVPT-P96) PEDVPT strains were compared in post-weaning PEDV-seronegative pigs by oral inoculation. PEDVPT-P5-inoculation induced typical diarrhea during 1-9 days post inoculation with fecal viral shedding persisting for 26 days. Compared to PEDVPT-P5, PEDVPT-P96 inoculation induced none-to-mild diarrhea and lower, delayed fecal viral shedding. Although PEDVPT-P96 elicited slightly lower neutralizing antibodies and PEDV-specific immunoglobulin G (IgG) and immunoglobulin A (IgA) titers, a reduction in pathogenicity and viral shedding of the subsequent challenge with PEDVPT-P5 were noted in both PEDVPT-P5- and PEDVPT-P96-inoculated pigs. Alignment and comparison of full-length sequences of PEDVPT-P5 and PEDVPT-P96 revealed 23 nucleotide changes and resultant 19 amino acid substitutions in non-structure proteins 2, 3, 4, 9, 14, 15, spike, open reading frame 3 (ORF3), and membrane proteins with no detectable deletion or insertion. The present study confirmed the pathogenicity of the PEDVPT isolate in conventional post-weaning pigs. Moreover, data regarding viral attenuation and potency of induced antibodies against PEDVPT-P5 identified PEDVPT-P96 as a potential live-attenuated vaccine candidate.

Final Report: Multi-Scale Analysis of Deformation and Failure in Polycrystalline Titanium Alloys Under High Strain-Rates

DTIC Science & Technology

2015-12-28

Masoud Anahid, Mahendra K. Samal , and Somnath Ghosh. Dwell fatigue crack nucleation model based on crystal plasticity finite element simulations of...induced crack nucleation in polycrystals. Model. Simul. Mater. Sci. Eng., 17, 064009. 19. Anahid, M., Samal , M. K. & Ghosh, S. (2011). Dwell fatigue...Jour. Plas., 24:428–454, 2008. 4. M. Anahid, M. K. Samal , and S. Ghosh. Dwell fatigue crack nucleation model based on crystal plasticity finite

Pichia pastoris Mut(S) strains are prone to misincorporation of O-methyl-L-homoserine at methionine residues when methanol is used as the sole carbon source.

PubMed

Schotte, Peter; Dewerte, Isabelle; De Groeve, Manu; De Keyser, Saskia; De Brabandere, Veronique; Stanssens, Patrick

2016-06-07

Over the last few decades the methylotrophic yeast Pichia pastoris has become a popular host for a wide range of products such as vaccines and therapeutic proteins. Several P. pastoris engineered strains and mutants have been developed to improve the performance of the expression system. Yield and quality of a recombinant product are important parameters to monitor during the host selection and development process but little information is published regarding quality differences of a product produced by different P. pastoris strains. We compared titer and quality of several Nanobodies(®) produced in wild type and Mut(S) strains. Titer in fed-batch fermentation was comparable between all strains for each Nanobody but a significant difference in quality was observed. Nanobodies expressed in Mut(S) strains contained a product variant with a Δ-16 Da mass difference that was not observed in wild type strains. This variant showed substitution of methionine residues due to misincorporation of O-methyl-L-homoserine, also called methoxine. Methoxine is likely synthesized by the enzymatic action of O-acetyl homoserine sulfhydrylase and we confirmed that Nanobodies produced in the corresponding knock-out strain contained no methoxine variants. We could show the incorporation of methoxine during biosynthesis by its addition to the culture medium. We showed that misincorporation of methoxine occurs particularly in P. pastoris Mut(S) strains. This reduction in product quality could outweigh the advantages of using Mut strains, such as lower oxygen and methanol demand, heat formation and in some cases improved expression. Methoxine incorporation in recombinant proteins is likely to occur when an excess of methanol is present during fermentation but can be avoided when the methanol feed rate protocol is carefully designed.

Pathway and kinetics of cyhalothrin biodegradation by Bacillus thuringiensis strain ZS-19

PubMed Central

Chen, Shaohua; Deng, Yinyue; Chang, Changqing; Lee, Jasmine; Cheng, Yingying; Cui, Zining; Zhou, Jianuan; He, Fei; Hu, Meiying; Zhang, Lian-Hui

2015-01-01

Cyhalothrin is a common environmental pollutant which poses increased risks to non-target organisms including human beings. This study reported for the first time a newly isolated strain, Bacillus thuringiensis ZS-19 completely degraded cyhalothrin in minimal medium within 72 h. The bacterium transformed cyhalothrin by cleavage of both the ester linkage and diaryl bond to yield six intermediate products. Moreover, a novel degradation pathway of cyhalothrin in strain ZS-19 was proposed on the basis of the identified metabolites. In addition to degradation of cyhalothrin, this strain was found to be capable of degrading 3-phenoxybenzoic acid, a common metabolite of pyrethroids. Furthermore, strain ZS-19 participated in efficient degradation of a wide range of pyrethroids including cyhalothrin, fenpropathrinn, deltamethrin, beta-cypermethrin, cyfluthrin and bifenthrin. Taken together, our results provide insights into the mechanism of cyhalothrin degradation and also highlight the promising potentials of B.thuringiensis ZS-19 in bioremediation of pyrethroid-contaminated environment. This is the first report of (i) degradation of cyhalothrin and other pyrethroids by B.thuringiensis, (ii) identification of 3-phenoxyphenyl acetonitrile and N-(2-isoproxy-phenyl)-4-phenoxy-benzamide as the metabolites in the degradation pathway of pyrethroids, and (iii) a pathway of degradation of cyhalothrin by cleavage of both the ester linkage and diaryl bond in a microorganism. PMID:25740758

Impact of Commercial Strain Use on Saccharomyces cerevisiae Population Structure and Dynamics in Pinot Noir Vineyards and Spontaneous Fermentations of a Canadian Winery

PubMed Central

Martiniuk, Jonathan T.; Pacheco, Braydon; Russell, Gordon; Tong, Stephanie; Backstrom, Ian; Measday, Vivien

2016-01-01

Wine is produced by one of two methods: inoculated fermentation, where a commercially-produced, single Saccharomyces cerevisiae (S. cerevisiae) yeast strain is used; or the traditional spontaneous fermentation, where yeast present on grape and winery surfaces carry out the fermentative process. Spontaneous fermentations are characterized by a diverse succession of yeast, ending with one or multiple strains of S. cerevisiae dominating the fermentation. In wineries using both fermentation methods, commercial strains may dominate spontaneous fermentations. We elucidate the impact of the winery environment and commercial strain use on S. cerevisiae population structure in spontaneous fermentations over two vintages by comparing S. cerevisiae populations in aseptically fermented grapes from a Canadian Pinot Noir vineyard to S. cerevisiae populations in winery-conducted fermentations of grapes from the same vineyard. We also characterize the vineyard-associated S. cerevisiae populations in two other geographically separate Pinot Noir vineyards farmed by the same winery. Winery fermentations were not dominated by commercial strains, but by a diverse number of strains with genotypes similar to commercial strains, suggesting that a population of S. cerevisiae derived from commercial strains is resident in the winery. Commercial and commercial-related yeast were also identified in the three vineyards examined, although at a lower frequency. There is low genetic differentiation and S. cerevisiae population structure between vineyards and between the vineyard and winery that persisted over both vintages, indicating commercial yeast are a driver of S. cerevisiae population structure. We also have evidence of distinct and persistent populations of winery and vineyard-associated S. cerevisiae populations unrelated to commercial strains. This study is the first to characterize S. cerevisiae populations in Canadian vineyards. PMID:27551920

Impact of Commercial Strain Use on Saccharomyces cerevisiae Population Structure and Dynamics in Pinot Noir Vineyards and Spontaneous Fermentations of a Canadian Winery.

PubMed

Martiniuk, Jonathan T; Pacheco, Braydon; Russell, Gordon; Tong, Stephanie; Backstrom, Ian; Measday, Vivien

2016-01-01

Wine is produced by one of two methods: inoculated fermentation, where a commercially-produced, single Saccharomyces cerevisiae (S. cerevisiae) yeast strain is used; or the traditional spontaneous fermentation, where yeast present on grape and winery surfaces carry out the fermentative process. Spontaneous fermentations are characterized by a diverse succession of yeast, ending with one or multiple strains of S. cerevisiae dominating the fermentation. In wineries using both fermentation methods, commercial strains may dominate spontaneous fermentations. We elucidate the impact of the winery environment and commercial strain use on S. cerevisiae population structure in spontaneous fermentations over two vintages by comparing S. cerevisiae populations in aseptically fermented grapes from a Canadian Pinot Noir vineyard to S. cerevisiae populations in winery-conducted fermentations of grapes from the same vineyard. We also characterize the vineyard-associated S. cerevisiae populations in two other geographically separate Pinot Noir vineyards farmed by the same winery. Winery fermentations were not dominated by commercial strains, but by a diverse number of strains with genotypes similar to commercial strains, suggesting that a population of S. cerevisiae derived from commercial strains is resident in the winery. Commercial and commercial-related yeast were also identified in the three vineyards examined, although at a lower frequency. There is low genetic differentiation and S. cerevisiae population structure between vineyards and between the vineyard and winery that persisted over both vintages, indicating commercial yeast are a driver of S. cerevisiae population structure. We also have evidence of distinct and persistent populations of winery and vineyard-associated S. cerevisiae populations unrelated to commercial strains. This study is the first to characterize S. cerevisiae populations in Canadian vineyards.

Vibrio aphrogenes sp. nov., in the Rumoiensis clade isolated from a seaweed.

PubMed

Tanaka, Mami; Endo, Shoko; Kotake, Fumihito; Al-Saari, Nurhidayu; Amin, A K M Rohul; Feng, Gao; Mino, Sayaka; Doi, Hidetaka; Ogura, Yoshitoshi; Hayashi, Tetsuya; Suda, Wataru; Hattori, Masahira; Yumoto, Isao; Sawabe, Toko; Sawabe, Tomoo; Araki, Toshiyoshi

2017-01-01

A novel strain Vibrio aphrogenes sp. nov. strain CA-1004T isolated from the surface of seaweed collected on the coast of Mie Prefecture in 1994 [1] was characterized using polyphasic taxonomy including multilocus sequence analysis (MLSA) and a genome based comparison. Both phylogenetic analyses on the basis of 16S rRNA gene sequences and MLSA based on eight protein-coding genes (gapA, gyrB, ftsZ, mreB, pyrH, recA, rpoA, and topA) showed the strain could be placed in the Rumoiensis clade in the genus Vibrio. Sequence similarities of the 16S rRNA gene and the multilocus genes against the Rumoiensis clade members, V. rumoiensis, V. algivorus, V. casei, and V. litoralis, were low enough to propose V. aphrogenes sp. nov. strain CA-1004T as a separate species. The experimental DNA-DNA hybridization data also revealed that the strain CA-1004T was separate from four known Rumoiensis clade species. The G+C content of the V. aphrogenes strain was determined as 42.1% based on the genome sequence. Major traits of the strain were non-motile, halophilic, fermentative, alginolytic, and gas production. A total of 27 traits (motility, growth temperature range, amylase, alginase and lipase productions, and assimilation of 19 carbon compounds) distinguished the strain from the other species in the Rumoiensis clade. The name V. aphrogenes sp. nov. is proposed for this species in the Rumoiensis clade, with CA-1004T as the type strain (JCM 31643T = DSM 103759T).

Serotype distribution and antimicrobial susceptibility of Streptococcus pneumoniae isolates from adult patients in Jakarta, Indonesia.

PubMed

Said, Wahyu F; Sukoto, Edy; Khoeri, Miftahuddin M; Kumalawati, July; Safari, Dodi

Currently, the data on pneumococcal invasive disease in the Indonesian population are limited. In this study, we investigated the serotype distribution and antimicrobial susceptibility of Streptococcus pneumoniae. These samples were isolated from the sputum of adult patients with non-specific clinical symptoms aged 18-87 years in Jakarta, Indonesia, from August to October 2014. Of the 349 sputum specimens, thirteen isolates were identified as S. pneumoniae strains (4%), with two strains each for serotype 19F, 3, and 15A, and one strain each for serotype/serogroup 13, 23A, 6, 34, 17F, 16F, and untypeable. Resistance to tetracycline was most common with only 5 of 13 strains being susceptible. In conclusion, these data provide an initial in the surveillance of invasive pneumococcus in the Indonesia population. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Bile resistance in Lactococcus lactis strains varies with cellular fatty acid composition: analysis by using different growth media.

PubMed

Kimoto-Nira, Hiromi; Kobayashi, Miho; Nomura, Masaru; Sasaki, Keisuke; Suzuki, Chise

2009-05-31

Bile resistance is one of the basic characteristics of probiotic bacteria. The aim of this study was to investigate the characteristics of bile resistance in lactococci by studying the relationship between bile resistance and cellular fatty acid composition in lactococcci grown on different media. We determined the bile resistance of 14 strains in lactose-free M17 medium supplemented with either glucose only (GM17) or lactose only (LM17). Gas chromatographic analyses of free lipids extracted from the tested strains were used for determining their fatty acid composition. A correlation analysis of all strains grown in both media revealed significant positive correlations between bile resistance and relative contents of hexadecanoic acid and octadecenoic acid, and negative correlations between bile resistance and relative contents of hexadecenoic acid and C-19 cyclopropane fatty acid. It is also a fact that the fatty acids associated with bile resistance depended on species, strain, and/or growth medium. In L. lactis subsp. cremoris strains grown in GM17 medium, the bile-resistant strains had significantly more octadecenoic acid than the bile-sensitive strains. In LM17 medium, bile-resistant strains had significantly more octadecenoic acid and significantly less C-19 cyclopropane fatty acid than the bile-sensitive strains. In L. lactis subsp. lactis strains, bile resistances of some of the tested strains were altered by growth medium. Some strains were resistant to bile in GM17 medium but sensitive to bile in LM17 medium. Some strains were resistant in both media tested. The strains grown in GM17 medium had significantly more hexadecanoic acid and octadecenoic acid, and significantly less tetradecanoic acid, octadecadienoic acid and C-19 cyclopropane fatty acid than the strains grown in LM17 medium. In conclusion, the fatty acid compositions of the bile-resistant lactococci differed from those of the bile-sensitive ones. More importantly, our data suggest that altering their fatty acid composition (i.e. increased hexadecanoic acid and octadecenoic acid and decreased hexadecenoic acid and C-19 cyclopropane fatty acid) by changing growth conditions may be a useful way to enhance their bile resistance in lactococci.

[Susceptibility surveillance of clinical isolates to fluoroquinolone antimicrobial agents from 2003 to 2008: post-marketing study of prulifloxacin].

PubMed

Kawai, Shin; Yoshida, Atsushi; Okazaki, Mitsuhiro; Tsujihara, Yoshito; Inuzuka, Kazuhisa; Takeuchi, Kazuhide; Yamashita, Naoko; Onodera, Makoto; Hiraishi, Toru; Ida, Takashi; Maebashi, Kazunori

2010-06-01

Yearly changes in the susceptibility of clinical isolates to ulifloxacin (UFX) and other fluoroquinolones were examined through surveys over 3 periods. In the first survey, 534 strains derived from 19 species were collected from clinical specimens during 6 months from December 2003 to May 2004. In the same way, 805 strains were collected from December 2005 to May 2006 in the second survey, and 863 strains were from December 2007 to May 2008 in the third survey. Over these 3 study periods, the susceptibilities of fluoroquinolones against methicillin-susceptible Staphylococcus aureus and Escherichia coli were decreased. The isolation frequency of levofloxacin-nonsusceptible strain was increased from 0% to 11.8% and from 14.6% to 20.8%, respectively. MIC90s of UFX against these pathogens were also increased, but its MIC90 for E. coli was 2 to 4 times lower than that of levofloxacin. On the other hand, the susceptibility of strains of Klebsiella pneumoniae to UFX was increased. Among the fluoroquinolones tested, UFX showed the most potent activity against Pseudomonas aeruginosa, and no changes in the MIC90s occurred during the surveillance. Although one strain of Streptococcus pneumoniae isolated in the third study period showed levofloxacin-resistance (MIC, 8 microg/mL), there were nearly no changes in the MIC90s of any agents tested including UFX against S. pneumoniae during the surveillance. As for other bacterial species, a tendency to increase in resistance to UFX was not observed. The activity of UFX against Salmonella spp. and Shigella spp. was superior/equal to those of fluoroquinolones tested.

Interleukin-17 protects against the Francisella tularensis live vaccine strain but not against a virulent F. tularensis type A strain.

PubMed

Skyberg, Jerod A; Rollins, Maryclare F; Samuel, Joshua W; Sutherland, Marjorie D; Belisle, John T; Pascual, David W

2013-09-01

Francisella tularensis is a highly infectious intracellular bacterium that causes the zoonotic infection tularemia. While much literature exists on the host response to F. tularensis infection, the vast majority of work has been conducted using attenuated strains of Francisella that do not cause disease in humans. However, emerging data indicate that the protective immune response against attenuated F. tularensis versus F. tularensis type A differs. Several groups have recently reported that interleukin-17 (IL-17) confers protection against the live vaccine strain (LVS) of Francisella. While we too have found that IL-17Rα(-/-) mice are more susceptible to F. tularensis LVS infection, our studies, using a virulent type A strain of F. tularensis (SchuS4), indicate that IL-17Rα(-/-) mice display organ burdens and pulmonary gamma interferon (IFN-γ) responses similar to those of wild-type mice following infection. In addition, oral LVS vaccination conferred equivalent protection against pulmonary challenge with SchuS4 in both IL-17Rα(-/-) and wild-type mice. While IFN-γ was found to be critically important for survival in a convalescent model of SchuS4 infection, IL-17 neutralization from either wild-type or IFN-γ(-/-) mice had no effect on morbidity or mortality in this model. IL-17 protein levels were also higher in the lungs of mice infected with the LVS rather than F. tularensis type A, while IL-23p19 mRNA expression was found to be caspase-1 dependent in macrophages infected with LVS but not SchuS4. Collectively, these results demonstrate that IL-17 is dispensable for host immunity to type A F. tularensis infection, and that induced and protective immunity differs between attenuated and virulent strains of F. tularensis.

Genetic and phenotypic characterization of methicillin-resistant staphylococci isolated from veterinary hospitals in South Korea.

PubMed

Moon, Bo Youn; Youn, Jung-Ho; Shin, Sook; Hwang, Sun Young; Park, Yong Ho

2012-05-01

Staphylococci were isolated from veterinary staff, hospitalized animals, and medical equipment from 2 major tertiary veterinary hospitals in South Korea to investigate antimicrobial resistance and genetic relatedness. The detection rate for staphylococci was 55.2% (111/201 samples), and 11 species were identified among the collected staphylococcal strains. The most prevalent species were Staphylococcus pseudintermedius (52/111, 46.8%), Staphylococcus epidermidis (21/111, 18.9%), and Staphylococcus aureus (19/111, 17.1%). The methicillin-resistance rates of staphylococci isolated from veterinary staff and medical equipment were higher than those from hospitalized animals. The genotype of methicillin-resistant S. aureus (MRSA) strains in the current study was sequence type (ST)72-SCCmec IVc-t324, which is similar to the genotype of prevalent MRSA strains in human beings and food animals in South Korea. Among the mecA-positive S. pseudintermedius isolates, SCCmec V was most prevalent in strains originating from both veterinary staff and hospitalized animals. SCCmec IVa was detected in methicillin-resistant S. epidermidis, whereas SCCmec IVc was found in other methicillin-resistant, coagulase-negative staphylococci. The SCCmec typing, antimicrobial susceptibility tests, and pulsed field gel electrophoresis results showed that methicillin-resistant staphylococci dissemination between hospitalized animals and veterinary staff is possible in South Korean veterinary hospitals.

Different sensitivity levels to norspermidine on biofilm formation in clinical and commensal Staphylococcus epidermidis strains.

PubMed

Ramón-Peréz, Miriam L; Díaz-Cedillo, Francisco; Contreras-Rodríguez, Araceli; Betanzos-Cabrera, Gabriel; Peralta, Humberto; Rodríguez-Martínez, Sandra; Cancino-Diaz, Mario E; Jan-Roblero, Janet; Cancino Diaz, Juan C

2015-02-01

Biofilm formation on medical and surgical devices is the main virulence factor of Staphylococcus epidermidis. A recent study has shown that norspermidine inhibits and disassembles the biofilm in the wild-type Bacillus subtilis NCBI3610 strain. In this study, the effect of norspermidine on S. epidermidis biofilm formation of clinical or commensal strains was tested. Biofilm producing strains of S. epidermidis were isolated from healthy skin (HS; n = 3), healthy conjunctiva (HC; n = 9) and ocular infection (OI; n = 19). All strains were treated with different concentrations of norspermidine, spermidine, putrescine, and cadaverine (1, 10, 25, 50 and 100 μM), and the biofilm formation was tested on microtiter plate. Besides, cell-free supernatants of S. epidermidis growth at 4 h and 40 h were analyzed by gas chromatography coupled to mass spectrometry (GC-MS) to detect norspermidine. Results showed that norspermidine at 25 μM and 100 μM prevented the biofilm formation in 45.16% (14/31) and 16.13% (5/31), respectively; only in one isolate from OI, norspermidine did not have effect. Other polyamines as spermidine, putrescine and cadaverine did not have effect on the biofilm formation of the strains tested. Norspermidine was also capable to disassemble a biofilm already formed. Norspermidine was detected in the 40 h cell-free supernatant of S. epidermidis by GC-MS. Norspermidine inhibited the biofilm development of S. epidermidis on the surface of contact lens. In this work, it was demonstrated that S. epidermidis produces and releases norspermidine causing an inhibitory effect on biofilm formation. Moreover, this is the first time showing that clinical S. epidermidis strains have different sensitivity to norspermidine, which suggest that the composition and structure of the biofilms is varied. We propose that norspermidine could potentially be used in the pre-treating of medical and surgical devices to inhibit the biofilm formation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Molecular basis for universal HLA-A*0201-restricted CD8+ T-cell immunity against influenza viruses.

PubMed

Valkenburg, Sophie A; Josephs, Tracy M; Clemens, E Bridie; Grant, Emma J; Nguyen, Thi H O; Wang, George C; Price, David A; Miller, Adrian; Tong, Steven Y C; Thomas, Paul G; Doherty, Peter C; Rossjohn, Jamie; Gras, Stephanie; Kedzierska, Katherine

2016-04-19

Memory CD8(+)T lymphocytes (CTLs) specific for antigenic peptides derived from internal viral proteins confer broad protection against distinct strains of influenza A virus (IAV). However, immune efficacy can be undermined by the emergence of escape mutants. To determine how T-cell receptor (TCR) composition relates to IAV epitope variability, we used ex vivo peptide-HLA tetramer enrichment and single-cell multiplex analysis to compare TCRs targeted to the largely conserved HLA-A*0201-M158and the hypervariable HLA-B*3501-NP418antigens. The TCRαβs for HLA-B*3501-NP418 (+)CTLs varied among individuals and across IAV strains, indicating that a range of mutated peptides will prime different NP418-specific CTL sets. Conversely, a dominant public TRAV27/TRBV19(+)TCRαβ was selected in HLA-A*0201(+)donors responding to M158 This public TCR cross-recognized naturally occurring M158variants complexed with HLA-A*0201. Ternary structures showed that induced-fit molecular mimicry underpins TRAV27/TRBV19(+)TCR specificity for the WT and mutant M158peptides, suggesting the possibility of universal CTL immunity in HLA-A*0201(+)individuals. Combined with the high population frequency of HLA-A*0201, these data potentially explain the relative conservation of M158 Moreover, our results suggest that vaccination strategies aimed at generating broad protection should incorporate variant peptides to elicit cross-reactive responses against other specificities, especially those that may be relatively infrequent among IAV-primed memory CTLs.

Complete Genome Sequence of Sporisorium scitamineum and Biotrophic Interaction Transcriptome with Sugarcane

PubMed Central

Benevenuto, Juliana; Peters, Leila P.; Carvalho, Giselle; Palhares, Alessandra; Quecine, Maria C.; Nunes, Filipe R. S.; Kmit, Maria C. P.; Wai, Alvan; Hausner, Georg; Aitken, Karen S.; Berkman, Paul J.; Fraser, James A.; Moolhuijzen, Paula M.; Coutinho, Luiz L.; Creste, Silvana; Vieira, Maria L. C.; Kitajima, João P.; Monteiro-Vitorello, Claudia B.

2015-01-01

Sporisorium scitamineum is a biotrophic fungus responsible for the sugarcane smut, a worldwide spread disease. This study provides the complete sequence of individual chromosomes of S. scitamineum from telomere to telomere achieved by a combination of PacBio long reads and Illumina short reads sequence data, as well as a draft sequence of a second fungal strain. Comparative analysis to previous available sequences of another strain detected few polymorphisms among the three genomes. The novel complete sequence described herein allowed us to identify and annotate extended subtelomeric regions, repetitive elements and the mitochondrial DNA sequence. The genome comprises 19,979,571 bases, 6,677 genes encoding proteins, 111 tRNAs and 3 assembled copies of rDNA, out of our estimated number of copies as 130. Chromosomal reorganizations were detected when comparing to sequences of S. reilianum, the closest smut relative, potentially influenced by repeats of transposable elements. Repetitive elements may have also directed the linkage of the two mating-type loci. The fungal transcriptome profiling from in vitro and from interaction with sugarcane at two time points (early infection and whip emergence) revealed that 13.5% of the genes were differentially expressed in planta and particular to each developmental stage. Among them are plant cell wall degrading enzymes, proteases, lipases, chitin modification and lignin degradation enzymes, sugar transporters and transcriptional factors. The fungus also modulates transcription of genes related to surviving against reactive oxygen species and other toxic metabolites produced by the plant. Previously described effectors in smut/plant interactions were detected but some new candidates are proposed. Ten genomic islands harboring some of the candidate genes unique to S. scitamineum were expressed only in planta. RNAseq data was also used to reassure gene predictions. PMID:26065709

Increasing rate of daptomycin non-susceptible strains of Staphylococcus aureus in patients with atopic dermatitis.

PubMed

Błażewicz, Izabela; Jaśkiewicz, Maciej; Piechowicz, Lidia; Neubauer, Damian; Nowicki, Roman J; Kamysz, Wojciech; Barańska-Rybak, Wioletta

2017-12-01

Daptomycin is a cyclic lipopeptide that is bactericidal against Staphylococcus aureus , including methicillin-resistant S. aureus (MRSA), vancomycin-intermediate S. aureus (VISA) and vancomycin-resistant S. aureus (VRSA) strains. Daptomycin exerts its antimicrobial effect by a calcium-dependent interaction with the cytoplasmic membrane resulting in depolarization, ion loss and rapid cell death. Unfortunately, loss of daptomycin susceptibility in S. aureus in the clinical setting has been noted. To evaluate the susceptibility profile to daptomycin among S. aureus strains isloted from patients with atopic dermatitis (AD). Another point was to correlate the results obtained by broth microdilution method and Etest, which is commonly applied in clinical setting. One hundred patients with the diagnosis of atopic dermatitis were microbiologically assessed for the carriage of S. aureus . Antimicrobial susceptibility tests were performed using broth-microdilution (BMD) and Etests for daptomycin. Staphylococcus aureus strains were isolated from the majority of our patients, either from the skin (73%) or the anterior nares (75%). Six of the 100 nasal swabs (6%) and 5 of the 100 skin swabs (5%) were positive for methicillin-resistant Staphylococcus aureus (MRSA). A total of 81 of 148 (54.7%) daptomycin non-susceptible isolates of S. aureus were identified by BMD. Only 19 of 81 were also classified as non-susceptible by Etest. Clinicians and microbiologists should be aware of the possibility of the emergence of daptomycin non-susceptibility (or increase in minimal inhibitory concentration) during prolonged therapy and closely monitor the susceptibility of persisting isolates that might be recovered during therapy.

Cryobacterium flavum sp. nov. and Cryobacterium luteum sp. nov., isolated from glacier ice.

PubMed

Liu, Qing; Liu, Hongcan; Wen, Ying; Zhou, Yuguang; Xin, Yuhua

2012-06-01

Gram-positive, rod-shaped bacteria, strains Hh8(T), Hh15(T) and Hh40-2, were isolated from the No. 1 glacier in Xinjiang, north-west China. Colonies of strain Hh8(T) were orange-yellow, convex and round on PYG plates. Strain Hh8(T) grew at 0-19 °C and pH 5.5-10.5. Colonies of strain Hh15(T), which was able to grow at 0-20 °C and pH 5.5-12, were lemon yellow, convex and round on PYG plates. Phylogenetic analysis based on 16S rRNA gene sequences showed that these three strains were related to members of the genus Cryobacterium. The major cellular fatty acids of the novel strains were anteiso-C(15:0), iso-C(16:0), iso-C(15:0) and anteiso-C(15:1) A. On the basis of phenotypic characteristics, phylogenetic analysis and DNA-DNA relatedness data, two novel species, Cryobacterium flavum sp. nov. (type strain Hh8(T) = CGMCC 1.11215(T) = NBRC 107879(T)) and Cryobacterium luteum sp. nov. (type strain Hh15(T) = CGMCC 1.11210(T) = NBRC 107880(T)), are proposed.

Comparative analysis of growth-phase-dependent gene expression in virulent and avirulent Streptococcus pneumoniae using a high-density DNA microarray.

PubMed

Ko, Kwan Soo; Park, Sulhee; Oh, Won Sup; Suh, Ji-Yoeun; Oh, Taejeong; Ahn, Sungwhan; Chun, Jongsik; Song, Jae-Hoon

2006-02-28

The global pattern of growth-dependent gene expres-sion in Streptococcus pneumoniae strains was evalu-ated using a high-density DNA microarray. Total RNAs obtained from an avirulent S. pneumoniae strain R6 and a virulent strain AMC96-6 were used to compare the expression patterns at seven time points (2.5, 3.5, 4.5, 5.5, 6.0, 6.5, and 8.0 h). The expression profile of strain R6 changed between log and station-ary growth (the Log-Stat switch). There were clear differences between the growth-dependent gene ex-pression profiles of the virulent and avirulent pneumo-coccal strains in 367 of 1,112 genes. Transcripts of genes associated with bacterial competence and capsular polysaccharide formation, as well as clpP and cbpA, were higher in the virulent strain. Our data suggest that late log or early stationary phase may be the most virulent phase of S. pneumoniae.

(13)C-metabolic flux analysis in S-adenosyl-L-methionine production by Saccharomyces cerevisiae.

PubMed

Hayakawa, Kenshi; Kajihata, Shuichi; Matsuda, Fumio; Shimizu, Hiroshi

2015-11-01

S-Adenosyl-L-methionine (SAM) is a major biological methyl group donor, and is used as a nutritional supplement and prescription drug. Yeast is used for the industrial production of SAM owing to its high intracellular SAM concentrations. To determine the regulation mechanisms responsible for such high SAM production, (13)C-metabolic flux analysis ((13)C-MFA) was conducted to compare the flux distributions in the central metabolism between Kyokai no. 6 (high SAM-producing) and S288C (control) strains. (13)C-MFA showed that the levels of tricarboxylic acid (TCA) cycle flux in SAM-overproducing strain were considerably increased compared to those in the S228C strain. Analysis of ATP balance also showed that a larger amount of excess ATP was produced in the Kyokai 6 strain because of increased oxidative phosphorylation. These results suggest that high SAM production in Kyokai 6 strains could be attributed to enhanced ATP regeneration with high TCA cycle fluxes and respiration activity. Thus, maintaining high respiration efficiency during cultivation is important for improving SAM production. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Comparative Genomic Analysis Reveals Habitat-Specific Genes and Regulatory Hubs within the Genus Novosphingobium

PubMed Central

Kumar, Roshan; Verma, Helianthous; Haider, Shazia; Bajaj, Abhay; Sood, Utkarsh; Ponnusamy, Kalaiarasan; Nagar, Shekhar; Shakarad, Mallikarjun N.; Negi, Ram Krishan; Singh, Yogendra; Khurana, J. P.; Gilbert, Jack A.

2017-01-01

ABSTRACT Species belonging to the genus Novosphingobium are found in many different habitats and have been identified as metabolically versatile. Through comparative genomic analysis, we identified habitat-specific genes and regulatory hubs that could determine habitat selection for Novosphingobium spp. Genomes from 27 Novosphingobium strains isolated from diverse habitats such as rhizosphere soil, plant surfaces, heavily contaminated soils, and marine and freshwater environments were analyzed. Genome size and coding potential were widely variable, differing significantly between habitats. Phylogenetic relationships between strains were less likely to describe functional genotype similarity than the habitat from which they were isolated. In this study, strains (19 out of 27) with a recorded habitat of isolation, and at least 3 representative strains per habitat, comprised four ecological groups—rhizosphere, contaminated soil, marine, and freshwater. Sulfur acquisition and metabolism were the only core genomic traits to differ significantly in proportion between these ecological groups; for example, alkane sulfonate (ssuABCD) assimilation was found exclusively in all of the rhizospheric isolates. When we examined osmolytic regulation in Novosphingobium spp. through ectoine biosynthesis, which was assumed to be marine habitat specific, we found that it was also present in isolates from contaminated soil, suggesting its relevance beyond the marine system. Novosphingobium strains were also found to harbor a wide variety of mono- and dioxygenases, responsible for the metabolism of several aromatic compounds, suggesting their potential to act as degraders of a variety of xenobiotic compounds. Protein-protein interaction analysis revealed β-barrel outer membrane proteins as habitat-specific hubs in each of the four habitats—freshwater (Saro_1868), marine water (PP1Y_AT17644), rhizosphere (PMI02_00367), and soil (V474_17210). These outer membrane proteins could play a key role in habitat demarcation and extend our understanding of the metabolic versatility of the Novosphingobium species. IMPORTANCE This study highlights the significant role of a microorganism’s genetic repertoire in structuring the similarity between Novosphingobium strains. The results suggest that the phylogenetic relationships were mostly influenced by metabolic trait enrichment, which is possibly governed by the microenvironment of each microbe’s respective niche. Using core genome analysis, the enrichment of a certain set of genes specific to a particular habitat was determined, which provided insights on the influence of habitat on the distribution of metabolic traits in Novosphingobium strains. We also identified habitat-specific protein hubs, which suggested delineation of Novosphingobium strains based on their habitat. Examining the available genomes of ecologically diverse bacterial species and analyzing the habitat-specific genes are useful for understanding the distribution and evolution of functional and phylogenetic diversity in the genus Novosphingobium. PMID:28567447

[FEATURES OF MASS-SPECTROMETRIC PROTEIN PROFILES OF STRAINS OF BRUCELLOSIS CAUSATIVE AGENT DURING PREPARATION OF CULTURE ON VARIOUS NUTRIENT MEDIA].

PubMed

Ulshina, D V; Kovalev, D A; Zhirov, A M; Zharinova, N V; Khudoleev, A A; Kogotkova, O I; Efremenko, V I; Evchenko, N I; Kulichenko, A N

2016-01-01

Carry out comparative analysis using time-of-flight mass-spectrometry with matrix laser desorption/ionization (MALDI-TOF MS) of protein profiles of brucellosis causative agents (Brucella melitensis Rev-1 and Brucella abortus 19BA), cultivated in various nutrient media: Albimi agar, brucellagar and erythrit-agar. Vaccine,strains: Brucella melitensis Rev-1 and Brucella abortus 19BA. Protein profiling in linear mode on Microflex "Bruker Daltonics" MALDI-TOF mass-spectrometer. A number of characteristic features of brucella mass-spectra was detected: in particular, preservation of the total qualitative composition of protein profiles of cultures and significant differences in the intensity of separate peaks depending on the nutrient medium used. Based on the analysis of the data obtained, use of Albimi agar as the nutrient medium for preparation of brucella culture samples for mass-spectrometric analysis was shown to be optimal.

Genome Sequencing and Comparative Analysis of Saccharomyces cerevisiae Strains of the Peterhof Genetic Collection

PubMed Central

Drozdova, Polina B.; Tarasov, Oleg V.; Matveenko, Andrew G.; Radchenko, Elina A.; Sopova, Julia V.; Polev, Dmitrii E.; Inge-Vechtomov, Sergey G.; Dobrynin, Pavel V.

2016-01-01

The Peterhof genetic collection of Saccharomyces cerevisiae strains (PGC) is a large laboratory stock that has accumulated several thousands of strains for over than half a century. It originated independently of other common laboratory stocks from a distillery lineage (race XII). Several PGC strains have been extensively used in certain fields of yeast research but their genomes have not been thoroughly explored yet. Here we employed whole genome sequencing to characterize five selected PGC strains including one of the closest to the progenitor, 15V-P4, and several strains that have been used to study translation termination and prions in yeast (25-25-2V-P3982, 1B-D1606, 74-D694, and 6P-33G-D373). The genetic distance between the PGC progenitor and S288C is comparable to that between two geographically isolated populations. The PGC seems to be closer to two bakery strains than to S288C-related laboratory stocks or European wine strains. In genomes of the PGC strains, we found several loci which are absent from the S288C genome; 15V-P4 harbors a rare combination of the gene cluster characteristic for wine strains and the RTM1 cluster. We closely examined known and previously uncharacterized gene variants of particular strains and were able to establish the molecular basis for known phenotypes including phenylalanine auxotrophy, clumping behavior and galactose utilization. Finally, we made sequencing data and results of the analysis available for the yeast community. Our data widen the knowledge about genetic variation between Saccharomyces cerevisiae strains and can form the basis for planning future work in PGC-related strains and with PGC-derived alleles. PMID:27152522

In vitro PGPR properties and osmotic tolerance of different Azospirillum native strains and their effects on growth of maize under drought stress.

PubMed

García, Julia E; Maroniche, Guillermo; Creus, Cecilia; Suárez-Rodríguez, Ramón; Ramirez-Trujillo, José Augusto; Groppa, María D

2017-09-01

Osmotic variations in the soil can affect bacterial growth diminishing the number of inoculated bacteria. In a scenario of water deficit having tolerant bacteria would be beneficial to achieve a better response of the plant to stress. Thus, selection of more resistant bacteria could be useful to design new inoculants to be used in arid zones. In this sense, a group of Azospirillum isolates deposited in INTA collection was characterized in order to select strains tolerant to osmotic stress. The results obtained demonstrated that Az19 strain has similar in vitro PGPR characteristics to Az39, the most used strain in Argentina for inoculants industries, with the advantage of a better tolerance to osmotic and salt stress. Inoculation of maize plants with this strain resulted in a better response against water deficit compared to Az39 strain, encouraging us to further study the behavior of this strain in greenhouse and field trials in view of developing new inoculants suitable for areas with water deficit. Copyright © 2017 Elsevier GmbH. All rights reserved.

Discovery of Phloeophagus Beetles as a Source of Pseudomonas Strains That Produce Potentially New Bioactive Substances and Description of Pseudomonas bohemica sp. nov.

PubMed

Saati-Santamaría, Zaki; López-Mondéjar, Rubén; Jiménez-Gómez, Alejandro; Díez-Méndez, Alexandra; Větrovský, Tomáš; Igual, José M; Velázquez, Encarna; Kolarik, Miroslav; Rivas, Raúl; García-Fraile, Paula

2018-01-01

Antimicrobial resistance is a worldwide problem that threatens the effectiveness of treatments for microbial infection. Consequently, it is essential to study unexplored niches that can serve for the isolation of new microbial strains able to produce antimicrobial compounds to develop new drugs. Bark beetles live in phloem of host trees and establish symbioses with microorganisms that provide them with nutrients. In addition, some of their associated bacteria play a role in the beetle protection by producing substances that inhibit antagonists. In this study the capacity of several bacterial strains, isolated from the bark beetles Ips acuminatus, Pityophthorus pityographus Cryphalus piceae , and Pityogenes bidentatus , to produce antimicrobial compounds was analyzed. Several isolates exhibited the capacity to inhibit Gram-positive and Gram-negative bacteria, as well as fungi. The genome sequence analysis of three Pseudomonas isolates predicted the presence of several gene clusters implicated in the production of already described antimicrobials and moreover, the low similarity of some of these clusters with those previously described, suggests that they encode new undescribed substances, which may be useful for developing new antimicrobial agents. Moreover, these bacteria appear to have genetic machinery for producing antitumoral and antiviral substances. Finally, the strain IA19 T showed to represent a new species of the genus Pseudomonas . The 16S rRNA gene sequence analysis showed that its most closely related species include Pseudomonas lutea, Pseudomonas graminis, Pseudomonas abietaniphila and Pseudomonas alkylphenolica, with 98.6, 98.5 98.4, and 98.4% identity, respectively. MLSA of the housekeeping genes gyr B, rpo B, and rpo D confirmed that strain IA19 T clearly separates from its closest related species. Average nucleotide identity between strains IA19 T and P. abietaniphila ATCC 700689 T , P. graminis DSM 11363 T , P. alkylphenolica KL28 T and P. lutea DSM 17257 T were 85.3, 80.2, 79.0, and 72.1%, respectively. Growth occurs at 4-37°C and pH 6.5-8. Optimal growth occurs at 28°C, pH 7-8 and up to 2.5% NaCl. Respiratory ubiquinones are Q9 (97%) and Q8 (3%). C16:0 and in summed feature 3 are the main fatty acids. Based on genotypic, phenotypic and chemotaxonomic characteristics, the description of Pseudomonas bohemica sp. nov. has been proposed. The type strain is IA19 T (=CECT 9403 T = LMG 30182 T ).

The 14alpha-Demethylasse(CYP51A1) Gene is Overexpressed in Venturia inaequalis Strains Resistant to Myclobutanil.

PubMed

Schnabel, G; Jones, A L

2001-01-01

ABSTRACT We identified the cytochrome P450 sterol 14alpha-demethylase (CYP51A1) gene from Venturia inaequalis and optional insertions located upstream from CYP51A1 and evaluated their potential role in conferring resistance to the sterol demethylation-inhibitor (DMI) fungicide my-clobutanil. The CYP51A1 gene was completely sequenced from one my-clobutanil sensitive (S) and two myclobutanil-resistant (R) strains. No nucleotide variation was found when the three sequences were aligned. Allele-specific polymerase chain reaction (PCR) analysis indicated that a previously described single base pair mutation that correlated with resistance to DMI fungicides in strains of other filamentous fungi was absent in 19 S and 32 R strains of V. inaequalis from Michigan and elsewhere. The sequencing results and PCR analyses suggest that resistance in these strains was not due to a mutation in the sterol demethylase target site for DMI fungicides. Expression of CYP51A1 was determined for strains from an orchard that had never been sprayed with DMI fungicides (baseline orchard), and the data provided a reference for evaluating the expression of strains collected from a research orchard and from three commercial Michigan apple orchards with a long history of DMI use and a high frequency of R strains. Overexpression of CYP51A1 was significantly higher in 9 of 11 R strains from the research orchard than in S strains from the baseline orchard. The high expression was correlated with the presence of a 553-bp insertion located upstream of CYP51A1. Overexpression of the CYP51A1 gene was also detected in eight of eight, five of nine, and nine of nine R strains from three commercial orchards, but the insertion was not detected in the majority of these strains. The results suggest that overexpression of the target-site CYP51A1 gene is an important mechanism of resistance in some field resistant strains of V. inaequalis, but other mechanisms of resistance also appear to exist.

Proteomics Analysis of the Causative Agent of Typhoid Fever

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ansong, Charles; Yoon, Hyunjin; Norbeck, Angela D.

2008-02-01

Typhoid fever is a potentially fatal disease caused by the bacterial pathogen Salmonella enterica serovar Typhi (S. typhi). S. typhi infection is a complex process that involves numerous bacterially-encoded virulence determinants, and these are thought to confer both stringent human host specificity and a high mortality rate. In the present study we used a liquid chromatography-mass spectrometry (LC-MS) based proteomics strategy to investigate the proteome of logarithmic, stationary phase, and low pH/low magnesium (MgM) S. typhi cultures. This represents the first large scale comprehensive characterization of the S. typhi proteome. Our analysis identified a total of 2066 S. typhi proteins.more » In an effort to identify putative S. typhi-specific virulence factors, we then compared our S. typhi results to those obtained in a previously published study of the S. typhimurium proteome under similar conditions (Adkins J.N. et al (2006) Mol Cell Prot). Comparative proteomic analysis of S. typhi (strain Ty2) and S. typhimurium (strains LT2 and 14028) revealed a subset of highly expressed proteins unique to S. typhi that were exclusively detected under conditions that mimic the infective state in macrophage cells. These proteins included CdtB, HlyE, and a conserved protein encoded by t1476. The differential expression of selected proteins was confirmed by Western blot analysis. Taken together with the current literature, our observations suggest that this subset of proteins may play a role in S. typhi pathogenesis and human host specificity. In addition, we observed products of the biotin (bio) operon displayed a higher abundance in the more virulent strains S. typhi-Ty2 and S. typhimurium-14028 compared to the virulence attenuated S. typhimurium strain LT2, suggesting bio proteins may contribute to Salmonella pathogenesis.« less

Analysis of the Saccharomyces cerevisiae pan-genome reveals a pool of copy number variants distributed in diverse yeast strains from differing industrial environments.

PubMed

Dunn, Barbara; Richter, Chandra; Kvitek, Daniel J; Pugh, Tom; Sherlock, Gavin

2012-05-01

Although the budding yeast Saccharomyces cerevisiae is arguably one of the most well-studied organisms on earth, the genome-wide variation within this species--i.e., its "pan-genome"--has been less explored. We created a multispecies microarray platform containing probes covering the genomes of several Saccharomyces species: S. cerevisiae, including regions not found in the standard laboratory S288c strain, as well as the mitochondrial and 2-μm circle genomes-plus S. paradoxus, S. mikatae, S. kudriavzevii, S. uvarum, S. kluyveri, and S. castellii. We performed array-Comparative Genomic Hybridization (aCGH) on 83 different S. cerevisiae strains collected across a wide range of habitats; of these, 69 were commercial wine strains, while the remaining 14 were from a diverse set of other industrial and natural environments. We observed interspecific hybridization events, introgression events, and pervasive copy number variation (CNV) in all but a few of the strains. These CNVs were distributed throughout the strains such that they did not produce any clear phylogeny, suggesting extensive mating in both industrial and wild strains. To validate our results and to determine whether apparently similar introgressions and CNVs were identical by descent or recurrent, we also performed whole-genome sequencing on nine of these strains. These data may help pinpoint genomic regions involved in adaptation to different industrial milieus, as well as shed light on the course of domestication of S. cerevisiae.

Analysis of the Saccharomyces cerevisiae pan-genome reveals a pool of copy number variants distributed in diverse yeast strains from differing industrial environments

PubMed Central

Dunn, Barbara; Richter, Chandra; Kvitek, Daniel J.; Pugh, Tom; Sherlock, Gavin

2012-01-01

Although the budding yeast Saccharomyces cerevisiae is arguably one of the most well-studied organisms on earth, the genome-wide variation within this species—i.e., its “pan-genome”—has been less explored. We created a multispecies microarray platform containing probes covering the genomes of several Saccharomyces species: S. cerevisiae, including regions not found in the standard laboratory S288c strain, as well as the mitochondrial and 2-μm circle genomes–plus S. paradoxus, S. mikatae, S. kudriavzevii, S. uvarum, S. kluyveri, and S. castellii. We performed array-Comparative Genomic Hybridization (aCGH) on 83 different S. cerevisiae strains collected across a wide range of habitats; of these, 69 were commercial wine strains, while the remaining 14 were from a diverse set of other industrial and natural environments. We observed interspecific hybridization events, introgression events, and pervasive copy number variation (CNV) in all but a few of the strains. These CNVs were distributed throughout the strains such that they did not produce any clear phylogeny, suggesting extensive mating in both industrial and wild strains. To validate our results and to determine whether apparently similar introgressions and CNVs were identical by descent or recurrent, we also performed whole-genome sequencing on nine of these strains. These data may help pinpoint genomic regions involved in adaptation to different industrial milieus, as well as shed light on the course of domestication of S. cerevisiae. PMID:22369888

Spirosoma jeollabukense sp. nov., isolated from soil.

PubMed

Li, Weilan; Ten, Leonid N; Lee, Seung-Yeol; Lee, Dong Hoon; Jung, Hee-Young

2018-04-01

A Gram-negative, non-motile, rod-shaped, aerobic bacterial strain, designated S2-3-6 T , was isolated from soil in Jeollabuk-do province, South Korea, and was characterized taxonomically using a polyphasic approach. According to a comparative 16S rRNA gene sequence analysis, strain S2-3-6 T belonged to the family Cytophagaceae and was most closely related to Spirosoma endophyticum EX36 T (98.2%), Spirosoma fluviale MSd3 T (96.0%), and Spirosoma linguale DSM 74 T (95.7%). Strain S2-3-6 T contained summed feature 3 (C16:1 ω7c/C16:1 ω6c), C16:1 ω5c, and C16:0 N alcohol as major cellular fatty acids, MK-7 as the predominant respiratory quinone, and phosphatidylethanolamine as the main polar lipid. The DNA G+C content of strain S2-3-6 T was 47.8%. Phenotypic and chemotaxonomic data supported the affiliation of strain S2-3-6 T to the genus Spirosoma. However, the DNA-DNA relatedness between strain S2-3-6 T and Spirosoma endophyticum KACC 17920 T was 27%, clearly showing that the isolate constitutes a new genospecies. Strain S2-3-6 T could be clearly differentiated from its closest neighbors based on its phenotypic, genotypic, and chemotaxonomic features. Therefore, strain S2-3-6 T represents a novel species of the genus Spirosoma, for which the name Spirosoma jeollabukense sp. nov. is proposed. The type strain is S2-3-6 T (= KCTC 52725 T  = JCM 32129 T ).

Draft Genome Sequence of Pedobacter sp. Strain NL19, a Producer of Potent Antibacterial Compounds

PubMed Central

2015-01-01

Here, we report the draft genome sequence of Pedobacter sp. strain NL19. The genome has 5.99 Mbp and a G+C content of 39.0%. NL19 was isolated from sludge from an abandoned uranium mine in the north of Portugal, and it produces potent antibacterials against Gram-positive and Gram-negative bacteria. PMID:25814603

Enhanced hydrogen production of Enterobacter aerogenes mutated by nuclear irradiation.

PubMed

Cheng, Jun; Liu, Min; Song, Wenlu; Ding, Lingkan; Liu, Jianzhong; Zhang, Li; Cen, Kefa

2017-03-01

Nuclear irradiation was used for the first time to generate efficient mutants of hydrogen-producing bacteria Enterobacter aerogenes, which were screened with larger colour circles of more fermentative acid by-products. E. aerogenes cells were mutated by nuclear irradiation of 60 Co γ-rays. The screened E. aerogenes ZJU1 mutant with larger colour circles enhanced the hydrogenase activity from 89.8 of the wild strain to 157.4mLH 2 /(gDWh). The hereditary stability of the E. aerogenes ZJU1 mutant was certified after over ten generations of cultivation. The hydrogen yield of 301mLH 2 /gglucose with the mutant was higher by 81.8% than that of 166mL/gglucose with the wild strain. The peak hydrogen production rate of 27.2mL/(L·h) with the mutant was higher by 40.9% compared with that of 19.3mL/(L·h) with the wild strain. The mutant produced more acetate and butyrate but less ethanol compared with the wild strain during hydrogen fermentation. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Properties of Salmonella isolates in the Czech Republic].

PubMed

Srámová, H; Karpísková, R; Dĕdicová, D; Sisák, F; Rychlík, I

1999-08-01

Based on a grant project "Use and importance of epidemiological markers in Salmonella enteritidis and Salmonella typhimurium in the spread of salmonelloses in children under two years of age" implemented in 1995 to 1997, the authors investigated epidemiological markers in 1,186 salmonella isolates; the strains were isolated from faeces of 838 sick children, from 266 faeces of their contacts, from 49 specimens of incriminated foods and from 33 smears from the children's environment. Of 1,186 Salmonella isolates 999 were strains of S. enteritidis, 39 strains of S. typhimurium and 148 strains were not identified. The markers of Salmonella isolates were investigated from the aspect of biotyping--98% S. enteritidis were formed by the biovar Jena. 2% by biovar Essen; sensitivity to antibiotics--94.5% Salmonella strains were sensitive to 12 selected antibiotics, 2.9% were resistant and in 2.6% the resistance was in the intermediate zone; phagotyping--in 808 strains of S. enteritidis PT 8--88% predominated, in S. typhimurium DT 104 and DT 141; assessment of plasmid profiles--in strains of S. enteritidis plasmid 55 kb predominated, in three strains of S. typhimurium a plasmid size 95 kb; virulence--was compared in 43 strains isolated from hospitalized children with a severe clinical course with 39 strains from children treated at home. In vitro tests revealed that hospitalization of affected children was associated with virulence of the strains (SE phagotype 8) and not with age. The presented results are discussed with regard to the epidemiological situation in the Czech Republic and in the world.

Free-Living Species of Carnivorous Mammals in Poland: Red Fox, Beech Marten, and Raccoon as a Potential Reservoir of Salmonella, Yersinia, Listeria spp. and Coagulase-Positive Staphylococcus.

PubMed

Nowakiewicz, Aneta; Zięba, Przemysław; Ziółkowska, Grażyna; Gnat, Sebastian; Muszyńska, Marta; Tomczuk, Krzysztof; Majer Dziedzic, Barbara; Ulbrych, Łukasz; Trościańczyk, Aleksandra

2016-01-01

The objective of the study was to examine a population of free-living carnivorous mammals most commonly found in Poland (red fox, beech marten, and raccoon) for the occurrence of bacteria that are potentially pathogenic for humans and other animal species and to determine their virulence potential (the presence of selected virulence genes). From the total pool of isolates obtained (n = 328), we selected 90 belonging to species that pose the greatest potential threat to human health: Salmonella spp. (n = 19; 4.51%), Yersinia enterocolitica (n = 10; 2.37%), Listeria monocytogenes and L. ivanovii (n = 21), and Staphylococcus aureus (n = 40; 9.5%). The Salmonella spp. isolates represented three different subspecies; S. enterica subsp. enterica accounted for a significant proportion (15/19), and most of the serotypes isolated (S. Typhimurium, S. Infantis, S. Newport and S. Enteritidis) were among the 10 non-typhoidal Salmonella serotypes that are most often responsible for infections in Europe, including Poland. Y. enterococlitica was detected in the smallest percentage of animals, but 60% of strains among the isolates tested possessed the ail gene, which is responsible for attachment and invasion. Potentially pathogenic Listeria species were isolated from approx. 5% of the animals. The presence of all tested virulence genes was shown in 35% of L. monocytogenes strains, while in the case of the other strains, the genes occurred in varying numbers and configurations. The presence of the inlA, inlC, hlyA, and iap genes was noted in all strains, whereas the genes encoding PI-PLC, actin, and internalin Imo2821 were present in varying percentages (from 80% to 55%). S. aureus was obtained from 40 individuals. Most isolates possessed the hla, hld (95% for each), and hlb (32.5%) genes encoding hemolysins as well as the gene encoding leukotoxin lukED (70%). In a similar percentage of strains (77.5%), the presence of at least one gene encoding enterotoxin was found, with 12.5% exhibiting the presence of egc-like variants. In two animals, we also noted the gene encoding the TSST-1 toxin. The results of the study showed that free-living animals may be a significant reservoir of bacteria that are potentially pathogenic for humans. The results of the statistical analysis revealed that, among the animals species studied, the red fox constitutes the most important source of infections.

Whole-genome sequencing of the efficient industrial fuel-ethanol fermentative Saccharomyces cerevisiae strain CAT-1.

PubMed

Babrzadeh, Farbod; Jalili, Roxana; Wang, Chunlin; Shokralla, Shadi; Pierce, Sarah; Robinson-Mosher, Avi; Nyren, Pål; Shafer, Robert W; Basso, Luiz C; de Amorim, Henrique V; de Oliveira, Antonio J; Davis, Ronald W; Ronaghi, Mostafa; Gharizadeh, Baback; Stambuk, Boris U

2012-06-01

The Saccharomyces cerevisiae strains widely used for industrial fuel-ethanol production have been developed by selection, but their underlying beneficial genetic polymorphisms remain unknown. Here, we report the draft whole-genome sequence of the S. cerevisiae strain CAT-1, which is a dominant fuel-ethanol fermentative strain from the sugarcane industry in Brazil. Our results indicate that strain CAT-1 is a highly heterozygous diploid yeast strain, and the ~12-Mb genome of CAT-1, when compared with the reference S228c genome, contains ~36,000 homozygous and ~30,000 heterozygous single nucleotide polymorphisms, exhibiting an uneven distribution among chromosomes due to large genomic regions of loss of heterozygosity (LOH). In total, 58 % of the 6,652 predicted protein-coding genes of the CAT-1 genome constitute different alleles when compared with the genes present in the reference S288c genome. The CAT-1 genome contains a reduced number of transposable elements, as well as several gene deletions and duplications, especially at telomeric regions, some correlated with several of the physiological characteristics of this industrial fuel-ethanol strain. Phylogenetic analyses revealed that some genes were likely associated with traits important for bioethanol production. Identifying and characterizing the allelic variations controlling traits relevant to industrial fermentation should provide the basis for a forward genetics approach for developing better fermenting yeast strains.

Escherichia coli serotype O157:H7 retention on solid surfaces and peroxide resistance is enhanced by dual-strain biofilm formation.

PubMed

Uhlich, Gaylen A; Rogers, Donna P; Mosier, Derek A

2010-08-01

In a previous study we showed that an Escherichia coli O157:H7 strain that was unable to form biofilm was retained in large numbers in dual-strain biofilms formed with an E. coli O-:H4 companion strain. In this study we tested additional companion strains for their ability to retain E. coli O157:H7 strain 0475s. Companion strains producing biofilm that withstood aggressive washes were able to significantly increase serotype O157:H7 retention. Dual-strain biofilms with certain companion strains retained higher percentages of strain 0475s, and that ability was independent of biofilm total cell numbers. Tests with additional non-biofilm-forming E. coli O157:H7 strains showed that enhancement by companion strains was not unique to strain 0475s. Experiments using an E. coli companion strain with deletions of various curli and cellulose genes indicated that dual-strain biofilm formation was dependent on companion strain properties. Strain 0475s was not able to generate biofilm or persist on plastic when grown in broth with a biofilm-forming companion and separated by a 0.2 microm porous membrane, indicating a requirement for intimate contact with the companion strain. When dual-strain biofilms and planktonic cells were challenged with 5% H(2)O(2), strain 0475 showed greater survival in biofilms with certain companion strains compared to the corresponding planktonic cells. The results of this study indicate that non-biofilm-forming E. coli O157:H7 strains are retained on solid surfaces associated with biofilms generated by companion strains. However, properties other than biofilm mass enable certain companion strains to retain greater numbers of E. coli O157:H7.

Molecular epidemiology and strain-specific characteristics of Streptococcus agalactiae at the herd and cow level.

PubMed

Mahmmod, Y S; Klaas, I C; Katholm, J; Lutton, M; Zadoks, R N

2015-10-01

Host-adaptation of Streptococcus agalactiae subpopulations has been described whereby strains that are commonly associated with asymptomatic carriage or disease in people differ phenotypically and genotypically from those causing mastitis in dairy cattle. Based on multilocus sequence typing (MLST), the most common strains in dairy herds in Denmark belong to sequence types (ST) that are also frequently found in people. The aim of this study was to describe epidemiological and diagnostic characteristics of such strains in relation to bovine mastitis. Among 1,199 cattle from 6 herds, cow-level prevalence of S. agalactiae was estimated to be 27.4% based on PCR and 7.8% based on bacteriological culture. Quarter-level prevalence was estimated at 2.8% based on bacteriological culture. Per herd, between 2 and 26 isolates were characterized by pulsed-field gel electrophoresis (PFGE) and MLST. Within each herd, a single PFGE type and ST predominated, consistent with a contagious mode of transmission or point source infection within herds. Evidence of within-herd evolution of S. agalactiae was detected with both typing methods, although ST belonged to a single clonal complex (CC) per herd. Detection of CC23 (3 herds) was associated with significantly lower approximate count (colony-forming units) at the quarter level and significantly lower cycle threshold value at the cow level than detection of CC1 (2 herds) or CC19 (1 herd), indicating a lower bacterial load in CC23 infections. Median values for the number of infected quarters and somatic cell count (SCC) were numerically but not significantly lower for cows infected with CC23 than for cows with CC1 or CC19. For all CC, an SCC threshold of 200,000 cells/mL was an unreliable indicator of infection status, and prescreening of animals based on SCC as part of S. agalactiae detection and eradication campaigns should be discouraged. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Potential of New Isolates of Dunaliella Salina for Natural β-Carotene Production

PubMed Central

Xu, Yanan; Wosu, Chiziezi I.; Ben-Amotz, Ami

2018-01-01

The halotolerant microalga Dunaliella salina has been widely studied for natural β-carotene production. This work shows biochemical characterization of three newly isolated Dunaliella salina strains, DF15, DF17, and DF40, compared with D. salina CCAP 19/30 and D. salina UTEX 2538 (also known as D. bardawil). Although all three new strains have been genetically characterized as Dunaliella salina strains, their ability to accumulate carotenoids and their capacity for photoprotection against high light stress are different. DF15 and UTEX 2538 reveal great potential for producing a large amount of β-carotene and maintained a high rate of photosynthesis under light of high intensity; however, DF17, DF40, and CCAP 19/30 showed increasing photoinhibition with increasing light intensity, and reduced contents of carotenoids, in particular β-carotene, suggesting that the capacity of photoprotection is dependent on the cellular content of carotenoids, in particular β-carotene. Strong positive correlations were found between the cellular content of all-trans β-carotene, 9-cis β-carotene, all-trans α-carotene and zeaxanthin but not lutein in the D. salina strains. Lutein was strongly correlated with respiration in photosynthetic cells and strongly related to photosynthesis, chlorophyll and respiration, suggesting an important and not hitherto identified role for lutein in coordinated control of the cellular functions of photosynthesis and respiration in response to changes in light conditions, which is broadly conserved in Dunaliella strains. Statistical analysis based on biochemical data revealed a different grouping strategy from the genetic classification of the strains. The significance of these data for strain selection for commercial carotenoid production is discussed. PMID:29389891

Characterization of the clustered regularly interspaced short palindromic repeats sites in Streptococcus mutans isolated from early childhood caries patients.

PubMed

Chen, Jing; Li, Tiancheng; Zhou, Xuedong; Cheng, Lei; Huo, Yuanyuan; Zou, Jing; Li, Yuqing

2017-11-01

The aim of this study was to analyze the characteristics of the clustered regularly interspaced short palindromic repeats (CRISPR) sites in 45 clinical Streptococcus mutans strains and their relationship to the clinical manifestations of early childhood caries (ECC). Forty-five S. mutans strains were isolated from the plaque samples taken from sixty-three children. CRISPR sites were sequenced and BLAST was used to compare these sites to those in the CRISPRTarget database. The association between the distribution of CRISPR sites and the manifestation of caries was analyzed by Chi-Square test. Further, biofilm formation (by crystal violet staining) and the synthesis of polysaccharide (by anthrone-sulfuric method) of all clinical isolated S. mutans strains with both CRISPR sites and no CRISPR site were comapared. Finally, acidogenicity and acidurity of two typical strains were determined using pH drop and acid tolerance assays. Biofilm formation and EPS synthesis by two typical strains were compared by 3D CLSM (Confocal Laser Scanning Microscope) assays and the expression of gtf genes were evaluated using qPCR. We found that most of the spacers in the clinical S. mutans strains were derived from Streptococcus phages APCM01 and M102. The number of CRISPR sites in these strains was associated with the clinical manifestations of ECC. Moreover, we found that the biofilm formation and EPS synthesis ability of the S. mutans strains with both CRISPR sites was significant improved. An association was found between the distribution of CRISPR sites and the clinical manifestations of caries. The CRISPR sites might contribute to the cariogenic potential of S. mutans. Copyright © 2017 Elsevier Ltd. All rights reserved.

Recombinant-attenuated Salmonella Pullorum strain expressing the hemagglutinin-neuraminidase protein of Newcastle disease virus (NDV) protects chickens against NDV and Salmonella Pullorum challenge

PubMed Central

Ding, Ke; Shang, Ke; Yu, Zu-Hua; Yu, Chuan; Jia, Yan-Yan; He, Lei; Liao, Cheng-Shui; Li, Jing; Zhang, Chun-Jie; Li, Yin-Ju; Wu, Ting-Cai

2018-01-01

Newcastle disease virus (NDV) and Salmonella Pullorum have significant damaging effects on the poultry industry, but no previous vaccine can protect poultry effectively. In this study, a recombinant-attenuated S. Pullorum strain secreting the NDV hemagglutinin-neuraminidase (HN) protein, C79-13ΔcrpΔasd (pYA-HN), was constructed by using the suicide plasmid pREasd-mediated bacteria homologous recombination method to form a new bivalent vaccine candidate against Newcastle disease (ND) and S. Pullorum disease (PD). The effect of this vaccine candidate was compared with those of the NDV LaSota and C79-13ΔcrpΔasd (pYA) strains. The serum hemagglutination inhibition antibody titers, serum immunoglobulin G (IgG) antibodies, secretory IgA, and stimulation index in lymphocyte proliferation were increased significantly more (p < 0.01) in chickens inoculated with C79-13ΔcrpΔasd (pYA-HN) than with C79-13ΔcrpΔasd (pYA) but were not significantly increased compared with the chickens immunized with the LaSota live vaccine (p > 0.05). Moreover, the novel strain provides 60% and 80% protective efficacy against the NDV virulent strain F48E9 and the S. Pullorum virulent strain C79-13. In summary, in this study, a recombinant-attenuated S. Pullorum strain secreting NDV HN protein was constructed. The generation of the S. Pullorum C79-13ΔcrpΔasd (pYA-HN) strain provides a foundation for the development of an effective living-vector double vaccine against ND and PD. PMID:29032660

Existence of various human parvovirus B19 genotypes in Chinese plasma pools: genotype 1, genotype 3, putative intergenotypic recombinant variants and new genotypes.

PubMed

Jia, Junting; Ma, Yuyuan; Zhao, Xiong; Huangfu, Chaoji; Zhong, Yadi; Fang, Chi; Fan, Rui; Lv, Maomin; Zhang, Jingang

2016-09-17

Human parvovirus B19 (B19V) is a frequent contaminant of blood and plasma-derived medicinal products. Three distinct genotypes of B19V have been identified. The distribution of the three B19V genotypes has been investigated in various regions or countries. However, in China, data on the existence of different B19V genotypes are limited. One hundred and eighteen B19V-DNA positive source plasma pool samples collected from three Chinese blood products manufacturers were analyzed. The subgenomic NS1/VP1u region junction of B19V was amplified by nested PCR. These amplified products were then cloned and subsequently sequenced. For genotyping, their phylogenetic inferences were constructed based on the NS1/VP1-unique region. Then putative recombination events were analyzed and identified. Phylogenetic analysis of 118 B19V sequences attributed 61.86 % to genotype 1a, 10.17 % to genotype 1b, and 17.80 % to genotype 3b. All the genotype 3b sequences obtained in this study grouped as a specific, closely related cluster with B19V strain D91.1. Four 1a/3b recombinants and 5 new atypical B19V variants with no recombination events were identified. There were at least 3 subtypes (1a, 1b and 3b) of B19V circulating in China. Furthermore, putative B19V 1a/3b recombinants and unclassified strains were identified as well. Such recombinant and unclassified strains may contribute to the genetic diversity of B19V and consequently complicate the B19V infection diagnosis and NAT screening. Further studies will be required to elucidate the biological significance of the recombinant and unclassified strains.

Multiple alcohol dehydrogenases but no functional acetaldehyde dehydrogenase causing excessive acetaldehyde production from ethanol by oral streptococci.

PubMed

Pavlova, Sylvia I; Jin, Ling; Gasparovich, Stephen R; Tao, Lin

2013-07-01

Ethanol consumption and poor oral hygiene are risk factors for oral and oesophageal cancers. Although oral streptococci have been found to produce excessive acetaldehyde from ethanol, little is known about the mechanism by which this carcinogen is produced. By screening 52 strains of diverse oral streptococcal species, we identified Streptococcus gordonii V2016 that produced the most acetaldehyde from ethanol. We then constructed gene deletion mutants in this strain and analysed them for alcohol and acetaldehyde dehydrogenases by zymograms. The results showed that S. gordonii V2016 expressed three primary alcohol dehydrogenases, AdhA, AdhB and AdhE, which all oxidize ethanol to acetaldehyde, but their preferred substrates were 1-propanol, 1-butanol and ethanol, respectively. Two additional dehydrogenases, S-AdhA and TdhA, were identified with specificities to the secondary alcohol 2-propanol and threonine, respectively, but not to ethanol. S. gordonii V2016 did not show a detectable acetaldehyde dehydrogenase even though its adhE gene encodes a putative bifunctional acetaldehyde/alcohol dehydrogenase. Mutants with adhE deletion showed greater tolerance to ethanol in comparison with the wild-type and mutant with adhA or adhB deletion, indicating that AdhE is the major alcohol dehydrogenase in S. gordonii. Analysis of 19 additional strains of S. gordonii, S. mitis, S. oralis, S. salivarius and S. sanguinis showed expressions of up to three alcohol dehydrogenases, but none showed detectable acetaldehyde dehydrogenase, except one strain that showed a novel ALDH. Therefore, expression of multiple alcohol dehydrogenases but no functional acetaldehyde dehydrogenase may contribute to excessive production of acetaldehyde from ethanol by certain oral streptococci.

Multiple alcohol dehydrogenases but no functional acetaldehyde dehydrogenase causing excessive acetaldehyde production from ethanol by oral streptococci

PubMed Central

Pavlova, Sylvia I.; Jin, Ling; Gasparovich, Stephen R.

2013-01-01

Ethanol consumption and poor oral hygiene are risk factors for oral and oesophageal cancers. Although oral streptococci have been found to produce excessive acetaldehyde from ethanol, little is known about the mechanism by which this carcinogen is produced. By screening 52 strains of diverse oral streptococcal species, we identified Streptococcus gordonii V2016 that produced the most acetaldehyde from ethanol. We then constructed gene deletion mutants in this strain and analysed them for alcohol and acetaldehyde dehydrogenases by zymograms. The results showed that S. gordonii V2016 expressed three primary alcohol dehydrogenases, AdhA, AdhB and AdhE, which all oxidize ethanol to acetaldehyde, but their preferred substrates were 1-propanol, 1-butanol and ethanol, respectively. Two additional dehydrogenases, S-AdhA and TdhA, were identified with specificities to the secondary alcohol 2-propanol and threonine, respectively, but not to ethanol. S. gordonii V2016 did not show a detectable acetaldehyde dehydrogenase even though its adhE gene encodes a putative bifunctional acetaldehyde/alcohol dehydrogenase. Mutants with adhE deletion showed greater tolerance to ethanol in comparison with the wild-type and mutant with adhA or adhB deletion, indicating that AdhE is the major alcohol dehydrogenase in S. gordonii. Analysis of 19 additional strains of S. gordonii, S. mitis, S. oralis, S. salivarius and S. sanguinis showed expressions of up to three alcohol dehydrogenases, but none showed detectable acetaldehyde dehydrogenase, except one strain that showed a novel ALDH. Therefore, expression of multiple alcohol dehydrogenases but no functional acetaldehyde dehydrogenase may contribute to excessive production of acetaldehyde from ethanol by certain oral streptococci. PMID:23637459

Aeribacillus composti sp. nov., a thermophilic bacillus isolated from olive mill pomace compost.

PubMed

Finore, Ilaria; Gioiello, Alessia; Leone, Luigi; Orlando, Pierangelo; Romano, Ida; Nicolaus, Barbara; Poli, Annarita

2017-11-01

A Gram-stain-positive, aerobic, endospore-forming, thermophilic bacterium, strain N.8 T , was isolated from the curing step of an olive mill pomace compost sample, collected at the Composting Experimental Centre (CESCO, Salerno, Italy). Strain N.8 T , based on 16S rRNA gene sequence similarities, was most closely related to Aeribacillus pallidus strain H12 T (=DSM 3670 T ) (99.8 % similarity value) with a 25 % DNA-DNA relatedness value. Cells were rod-shaped, non-motile and grew optimally at 60 °C and pH 9.0, forming cream colonies. Strain N.8 was able to grow on medium containing up to 9.0 % (w/v) NaCl with an optimum at 6.0 % (w/v) NaCl. The cellular membrane contained MK-7, and C16 : 0 (48.4 %), iso-C17 : 0 (19.4 %) and anteiso-C17 : 0 (14.6 %) were the major cellular fatty acids. The DNA G+C content was 40.5 mol%. Based on phenotypic characteristics, 16S rRNA gene sequences, DNA-DNA hybridization values and chemotaxonomic characteristics, strain N.8 T represents a novel species of the genus Aeribacillus, for which the name Aeribacillus composti sp. nov. is proposed. The type strain is N.8 T (=KCTC 33824 T =JCM 31580 T ).

Physical strain of comfortable walking in children with mild cerebral palsy.

PubMed

Dallmeijer, Annet J; Brehm, Merel-Anne

2011-01-01

To evaluate the physical strain of comfortable walking in children with mild cerebral palsy (CP) in comparison to typically developing (TD) children. Physical strain was defined as the oxygen uptake during walking (VO(2walk)) expressed as a percentage of their maximal aerobic capacity (VO(2peak)). Eighteen children (aged 8-16 years) participated, including eight ambulant children (four girls, four boys) with mild spastic CP (three hemiplegia, five diplegia, GMFCS I: n = 7 and II: n = 1) and 10 TD children. VO(2walk) was measured during 5 min of walking on an indoor track at comfortable walking speed. VO(2peak) was measured in a shuttle run test. VO(2walk) was significantly higher in CP (19.7 (2.8) ml/kg/min) compared to TD (16.8 (3.6) ml/kg/min, p = 0.033), while walking speed did not differ significantly between groups. VO(2peak) was significantly lower in CP (37.2 (2.2) ml/kg/min) compared to TD (45.0 (5.3) ml/kg/min, p = 0.001). Consequently, the physical strain during walking was significantly higher in CP (52 (7.7) %) compared to TD (36 (8.4) %, p = 0.001). The higher physical strain during comfortable walking of children with mild CP compared to TD children may be related to reported problems with fatigue in this population, and suggest a need for physical aerobic training programmes.

Demonstration of an adaptive response to preconditioning Frankliniella occidentalis (Pergande) to sublethal doses of spinosad: a hormetic-dose response.

PubMed

Gong, Youhui; Xu, Baoyun; Zhang, Youjun; Gao, Xiwu; Wu, Qingjun

2015-07-01

Sublethal doses of some insecticides have been reported to either stimulate or reduce the survival and fecundity of insects. Many sublethal-effect studies have been conducted after exposure of only one generation to sublethal insecticides, and there is little information about the sublethal effects on insects after long-term exposure to sublethal insecticides. In this study, changes in biological characteristics were investigated in spinosad-susceptible (Spin-S) and sublethal-spinosad-treated (Spin-Sub) strains of Frankliniella occidentalis (Pergande) after exposure to their corresponding sublethal concentrations of spinosad. The results showed that for the Spin-S strain, the LC10 concentration of spinosad slightly affected the biotic fitness both in parents and offspring of F. occidentalis. The LC25 concentration of spinosad prolonged the development time, reduced the fecundity, and significantly reduced the intrinsic rate of increase, the net reproductive rate and the finite rate of increase in the Spin-S strain. However, the negative effects were not as pronounced in the offspring (F1 generation) as in the parent generation. For the Spin-Sub strain, the LC10 and LC25 concentrations of spinosad had little negative effect on the development and fecundity, and no significant difference was found between the effects of the LC10 and LC25 treatments on the Spin-Sub strain. The Spin-Sub strain exhibited a shorter developmental time, and larger intrinsic rates of increase and net reproductive rates, compared with the corresponding treatments of the Spin-S strain. These findings combined with our previous studies suggest that the biotic fitness increased in the Spin-Sub strain and the strain became more adaptable to sublethal doses of spinosad, compared with the Spin-S strain. Physiological and biochemical adaptation may contribute to these changes after long treatment times at sublethal doses.

StreptoBase: An Oral Streptococcus mitis Group Genomic Resource and Analysis Platform.

PubMed

Zheng, Wenning; Tan, Tze King; Paterson, Ian C; Mutha, Naresh V R; Siow, Cheuk Chuen; Tan, Shi Yang; Old, Lesley A; Jakubovics, Nicholas S; Choo, Siew Woh

2016-01-01

The oral streptococci are spherical Gram-positive bacteria categorized under the phylum Firmicutes which are among the most common causative agents of bacterial infective endocarditis (IE) and are also important agents in septicaemia in neutropenic patients. The Streptococcus mitis group is comprised of 13 species including some of the most common human oral colonizers such as S. mitis, S. oralis, S. sanguinis and S. gordonii as well as species such as S. tigurinus, S. oligofermentans and S. australis that have only recently been classified and are poorly understood at present. We present StreptoBase, which provides a specialized free resource focusing on the genomic analyses of oral species from the mitis group. It currently hosts 104 S. mitis group genomes including 27 novel mitis group strains that we sequenced using the high throughput Illumina HiSeq technology platform, and provides a comprehensive set of genome sequences for analyses, particularly comparative analyses and visualization of both cross-species and cross-strain characteristics of S. mitis group bacteria. StreptoBase incorporates sophisticated in-house designed bioinformatics web tools such as Pairwise Genome Comparison (PGC) tool and Pathogenomic Profiling Tool (PathoProT), which facilitate comparative pathogenomics analysis of Streptococcus strains. Examples are provided to demonstrate how StreptoBase can be employed to compare genome structure of different S. mitis group bacteria and putative virulence genes profile across multiple streptococcal strains. In conclusion, StreptoBase offers access to a range of streptococci genomic resources as well as analysis tools and will be an invaluable platform to accelerate research in streptococci. Database URL: http://streptococcus.um.edu.my.

Superantigen profiles of emm and emm-like typeable and nontypeable pharyngeal streptococcal isolates of South India.

PubMed

Anand, Thangarajan Durai; Rajesh, Thangamani; Rajendhran, Jeyaprakash; Gunasekaran, Paramasamy

2012-02-02

The major virulence factors determining the pathogenicity of streptococcal strains include M protein encoded by emm and emm-like (emmL) genes and superantigens. In this study, the distribution of emm, emmL and superantigen genes was analyzed among the streptococcal strains isolated from the patients of acute pharyngitis. The streptococcal strains were isolated from the throat swabs of 1040 patients of acute pharyngitis. The emm and emmL genes were PCR amplified from each strain and sequenced to determine the emm types. The dot-blot hybridization was performed to confirm the pathogens as true emm nontypeable strains. The presence of eleven currently known superantigens was determined in all the strains by multiplex PCR. Totally, 124 beta-hemolytic streptococcal strains were isolated and they were classified as group A streptococcus (GAS) [15.3% (19/124)], group C streptococcus (GCS) [59.7% (74/124)] and group G streptococcus (GGS) [25.0% (31/124)]. Among 124 strains, only 35 strains were emm typeable and the remaining 89 strains were emm nontypeable. All GAS isolates were typeable, whereas most of the GCS and GGS strains were nontypeable. These nontypeable strains belong to S. anginosus [75.3% (67/89)] and S. dysgalactiae subsp. equisimilis [24.7% (22/89)]. The emm and emmL types identified in this study include emm12.0 (28.6%), stG643.0 (28.6%), stC46.0 (17.0%), emm30.11 (8.5%), emm3.0 (2.9%), emm48.0 (5.7%), st3343.0 (2.9%), emm107.0 (2.9%) and stS104.2 (2.9%). Various superantigen profiles were observed in typeable as well as nontypeable strains. Multiplex PCR analysis revealed the presence of superantigens in all the typeable strains irrespective of their emm types. However, the presence of superantigen genes in emm and emmL nontypeable strains has not been previously reported. In this study, presence of at least one or a combination of superantigen coding genes was identified in all the emm and emmL nontypeable strains. Thus, the superantigens may inevitably play an important role in the pathogenesis of these nontypeable strains in the absence of the primary virulence factor, M protein.

Superantigen profiles of emm and emm-like typeable and nontypeable pharyngeal streptococcal isolates of South India

PubMed Central

2012-01-01

Background The major virulence factors determining the pathogenicity of streptococcal strains include M protein encoded by emm and emm-like (emmL) genes and superantigens. In this study, the distribution of emm, emmL and superantigen genes was analyzed among the streptococcal strains isolated from the patients of acute pharyngitis. Methods The streptococcal strains were isolated from the throat swabs of 1040 patients of acute pharyngitis. The emm and emmL genes were PCR amplified from each strain and sequenced to determine the emm types. The dot-blot hybridization was performed to confirm the pathogens as true emm nontypeable strains. The presence of eleven currently known superantigens was determined in all the strains by multiplex PCR. Results Totally, 124 beta-hemolytic streptococcal strains were isolated and they were classified as group A streptococcus (GAS) [15.3% (19/124)], group C streptococcus (GCS) [59.7% (74/124)] and group G streptococcus (GGS) [25.0% (31/124)]. Among 124 strains, only 35 strains were emm typeable and the remaining 89 strains were emm nontypeable. All GAS isolates were typeable, whereas most of the GCS and GGS strains were nontypeable. These nontypeable strains belong to S. anginosus [75.3% (67/89)] and S. dysgalactiae subsp. equisimilis [24.7% (22/89)]. The emm and emmL types identified in this study include emm12.0 (28.6%), stG643.0 (28.6%), stC46.0 (17.0%), emm30.11 (8.5%), emm3.0 (2.9%), emm48.0 (5.7%), st3343.0 (2.9%), emm107.0 (2.9%) and stS104.2 (2.9%). Various superantigen profiles were observed in typeable as well as nontypeable strains. Conclusions Multiplex PCR analysis revealed the presence of superantigens in all the typeable strains irrespective of their emm types. However, the presence of superantigen genes in emm and emmL nontypeable strains has not been previously reported. In this study, presence of at least one or a combination of superantigen coding genes was identified in all the emm and emmL nontypeable strains. Thus, the superantigens may inevitably play an important role in the pathogenesis of these nontypeable strains in the absence of the primary virulence factor, M protein. PMID:22296671

Phenotypic evaluation and characterization of 21 industrial Saccharomyces cerevisiae yeast strains.

PubMed

Kong, In Iok; Turner, Timothy Lee; Kim, Heejin; Kim, Soo Rin; Jin, Yong-Su

2018-02-01

Microorganisms have been studied and used extensively to produce value-added fuels and chemicals. Yeasts, specifically Saccharomyces cerevisiae, receive industrial attention because of their well-known ability to ferment glucose and produce ethanol. Thousands of natural or genetically modified S. cerevisiae have been found in industrial environments for various purposes. These industrial strains are isolated from industrial fermentation sites, and they are considered as potential host strains for superior fermentation processes. In many cases, industrial yeast strains have higher thermotolerance, increased resistances towards fermentation inhibitors and increased glucose fermentation rates under anaerobic conditions when compared with laboratory yeast strains. Despite the advantages of industrial strains, they are often not well characterized. Through screening and phenotypic characterization of commercially available industrial yeast strains, industrial fermentation processes requiring specific environmental conditions may be able to select an ideal starting yeast strain to be further engineered. Here, we have characterized and compared 21 industrial S. cerevisiae strains under multiple conditions, including their tolerance to varying pH conditions, resistance to fermentation inhibitors, sporulation efficiency and ability to ferment lignocellulosic sugars. These data may be useful for the selection of a parental strain for specific biotechnological applications of engineered yeast. © FEMS 2018. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Magnitude of sarcomere extension correlates with initial sarcomere length during lengthening of activated single fibers from soleus muscle of rats.

PubMed

Panchangam, Appaji; Claflin, Dennis R; Palmer, Mark L; Faulkner, John A

2008-08-01

A laser-diffraction technique was developed that rapidly reports the lengths of sarcomeres (L(s)) in serially connected sectors of permeabilized single fibers. The apparatus translates a laser beam along the entire length of a fiber segment within 2 ms, with brief stops at each of 20 contiguous sectors. We tested the hypothesis that during lengthening contractions, when maximally activated fibers are stretched, sectors that contain the longer sarcomeres undergo greater increases in L(s) than those containing shorter sarcomeres. Fibers (n = 16) were obtained from the soleus muscles of adult male rats and the middle portions (length = 1.05 +/- 0.11 mm; mean +/- SD) were investigated. Single stretches of strain 27% and a strain rate of 54% s(-1) were initiated at maximum isometric stress and resulted in a 19 +/- 9% loss in isometric stress. The data on L(s) revealed that 1), the stretch was not distributed uniformly among the sectors, and 2), during the stretch, sectors at long L(s) before the stretch elongated more than those at short lengths. The findings support the hypothesis that during stretches of maximally activated skeletal muscles, sarcomeres at longer lengths are more susceptible to damage by excessive strain.

Screening of marine fungus from Nanji Island and activity of their metabolites against pathogenic Vibrio from Pseudosciaena crocea

NASA Astrophysics Data System (ADS)

Zhao, Shujiang; Li, Shuping; Liu, Huihui; Zhao, Qian; Wang, Jieyou; Yan, Maocang

2012-09-01

Seventy-eight marine fungal strains were isolated from sediment samples collected off the coast of Nanji Island, Wenzhou, Zhejiang Province, China. Antibacterial screening using the agar disc method showed that 19 of the isolated strains could inhibit at least one pathogenic V ibrio from P seudosciaena crocea. Subsequent screening confirmed that nine strains produced antibacterial metabolites that had activity against one or several types of pathogenic V ibrio. Strain NJ0104 had the widest antimicrobial spectrum and strong activity, particularly against Vibrio parahaemolyticus-MM0810072. A preliminary study of NJ0104 antibacterial metabolites demonstrated that they had thermal stability up to 80°C, ultraviolet stability up to 40 min and pH stability between 4.0-7.0. In addition, the antibacterial metabolites were readily soluble in butanol. To identify the specific strain, the ITS-5.8S rDNA regions of NJ0104 were PCR amplified and sequenced. Based on the combination of phenotypic and genotypic data, the strain was identified as Arthrinium sp.

[Identification of Hydrocarbon-Oxidizing Dietzia Bacteria from Petroleum Reservoirs Based on Phenotypic Properties and Analysis of the 16S rRNA and gyrB Genes].

PubMed

Nazina, T N; Shumkova, E S; Sokolova, D Sh; Babich, T L; Zhurina, M V; Xue, Yan-Fen; Osipov, G A; Poltaraus, A B; Tourova, T P

2015-01-01

The taxonomic position of hydrocarbon-oxidizing bacterial strains 263 and 32d isolated from formation water of the Daqing petroleum reservoir (PRC) was determined by polyphasic taxonomy techniques, including analysis of the 16S rRNA and the gyrB genes. The major chemotaxonomic characteristics of both strains, including the IV type cell wall, composition of cell wall fatty acids, mycolic acids, and menaquinones, agreed with those typical of Dietzia strains. The DNA G+C content of strains 263 and 32d were 67.8 and 67.6 mol%, respectively. Phylogenetic analysis of the 16S rRNA gene of strain 32d revealed 99.7% similarity to the gene of D. maris, making it possible to identify strain 32d as belonging to this species. The 16S rRNA gene sequence of strain 263 exhibited 99.7 and 99.9% similarity to those of D. natronolimnaea and D. cercidiphylli YIM65002(T), respectively. Analysis of the gyrB genes of the subterranean isolates and of a number of Dietzia type strains confirmed classiffication of strain 32d as a D. maris strain and of strain 263, as a D. natronolimnaea strain. A conclusion was made concerning higher resolving power of phylogenetic analysis of the gyrB gene compared to the 16S rRNA gene analysis in the case of determination of the species position of Dietzia isolates.

Identification of "Haematobacter," a new genus of aerobic Gram-negative rods isolated from clinical specimens, and reclassification of Rhodobacter massiliensis as "Haematobacter massiliensis comb. nov.".

PubMed

Helsel, Leta O; Hollis, Dannie; Steigerwalt, Arnold G; Morey, Roger E; Jordan, Jean; Aye, Tin; Radosevic, Jon; Jannat-Khah, Deanna; Thiry, Dorothy; Lonsway, David R; Patel, Jean B; Daneshvar, Maryam I; Levett, Paul N

2007-04-01

Twelve strains of gram-negative, nonfermenting rods recovered mainly from septicemic patients were studied using conventional and molecular methods. The phenotypic profiles of these strains most closely resembled Psychrobacter phenylpyruvicus. They produced catalase, oxidase, urease, and H(2)S (lead acetate paper) but did not produce indole, reduce nitrate or nitrite, or hydrolyze gelatin or esculin. No acid production was observed in a King's oxidation-fermentation base containing d-glucose, d-xylose, d-mannitol, sucrose, lactose, or maltose. All strains were nonmotile and nonpigmented. Most strains produced green discoloration on blood agar. All strains grew at 25 degrees C and 35 degrees C and most grew on MacConkey agar. They shared a common cellular fatty acid (CFA) profile characterized by large amounts (56% to 90%) of 18:1omega7c and the presence of 3-OH-10:0, 16:1omega7c, 16:0, and 19:0cycomega8c that overall was most similar to that of Rhodobacter species but was quite distinct from that of P. phenylpyruvicus. The MICs for most beta-lactams, fluoroquinolones, aminoglycosides, and carbapenems were low. MICs for aztreonam and piperacillin were higher, with MICs for some strains of > 64 mg/liter and > 128 mg/liter, respectively. Polyphasic analysis of these strains, including morphological, biochemical, CFA composition, DNA-DNA hybridization, 16S rRNA gene sequencing, and percent guanine-plus-cytosine (G+C) content analysis, demonstrated that these strains and Rhodobacter massiliensis represent a new genus, "Haematobacter" (proposed name), with the species H. missouriensis (type strain H1892(T) = CCUG 52307(T) = CIP 109176(T)) and H. massiliensis comb. nov. (type strain Framboise(T) = CCUG 47968(T) = CIP 107725(T)) and an unnamed genomospecies.

Lactobacillus panisapium sp. nov., from honeybee Apis cerana bee bread.

PubMed

Wang, Cong; Huang, Yan; Li, Li; Guo, Jun; Wu, Zhengyun; Deng, Yu; Dai, Lirong; Ma, Shichun

2018-03-01

A novel facultatively anaerobic, Gram-stain-positive, non-motile, non-spore-forming, catalase-negative bacterium of the genus Lactobacillus, designated strain Bb 2-3 T , was isolated from bee bread of Apis cerana collected from a hive in Kunming, China. The strain was regular rod-shaped. Optimal growth occurred at 37 °C, pH 6.5 with 5.0 g l -1 NaCl. The predominant fatty acids were C18 : 1ω9c, C16 : 0 and C19 : 0 iso. Respiratory quinones were not detected. Seven glycolipids, three lipids, phosphatidylglycerol and diphosphatidylglycerol were detected. The peptidoglycan type A4α l-Lys-d-Asp was determined. Strain Bb 2-3 T was closely related to Lactobacillus bombicola DSM 28793 T , Lactobacillus apis LMG 26964 T and Lactobacillus helsingborgensis DSM 26265 T , with 97.8, 97.6 and 97.0 % 16S rRNA gene sequence similarity, respectively. A comparison of two housekeeping genes, rpoA and pheS, revealed that strain Bb 2-3 T was well separated from the reference strains of species of the genus Lactobacillus. The average nucleotide identity between strain Bb 2-3 T and the type strains of closely related species was lower than the 95-96 % threshold value for delineation of genomic prokaryotic species. The G+C content of the genomic DNA of strain Bb 2-3 T was 37.4 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic analyses, strain Bb 2-3 T is proposed to represent a novel species of the genus Lactobacillus, for which we propose the name Lactobacillus panisapium sp. nov. The type strain is Bb 2-3 T (=DSM 102188 T =ACCC 19955 T ).

Genetic Diversity of Crimean Congo Hemorrhagic Fever Virus Strains from Iran

PubMed Central

Chinikar, Sadegh; Bouzari, Saeid; Shokrgozar, Mohammad Ali; Mostafavi, Ehsan; Jalali, Tahmineh; Khakifirouz, Sahar; Nowotny, Norbert; Fooks, Anthony R.; Shah-Hosseini, Nariman

2016-01-01

Background: Crimean Congo hemorrhagic fever virus (CCHFV) is a member of the Bunyaviridae family and Nairovirus genus. It has a negative-sense, single stranded RNA genome approximately 19.2 kb, containing the Small, Medium, and Large segments. CCHFVs are relatively divergent in their genome sequence and grouped in seven distinct clades based on S-segment sequence analysis and six clades based on M-segment sequences. Our aim was to obtain new insights into the molecular epidemiology of CCHFV in Iran. Methods: We analyzed partial and complete nucleotide sequences of the S and M segments derived from 50 Iranian patients. The extracted RNA was amplified using one-step RT-PCR and then sequenced. The sequences were analyzed using Mega5 software. Results: Phylogenetic analysis of partial S segment sequences demonstrated that clade IV-(Asia 1), clade IV-(Asia 2) and clade V-(Europe) accounted for 80 %, 4 % and 14 % of the circulating genomic variants of CCHFV in Iran respectively. However, one of the Iranian strains (Iran-Kerman/22) was associated with none of other sequences and formed a new clade (VII). The phylogenetic analysis of complete S-segment nucleotide sequences from selected Iranian CCHFV strains complemented with representative strains from GenBank revealed similar topology as partial sequences with eight major clusters. A partial M segment phylogeny positioned the Iranian strains in either association with clade III (Asia-Africa) or clade V (Europe). Conclusion: The phylogenetic analysis revealed subtle links between distant geographic locations, which we propose might originate either from international livestock trade or from long-distance carriage of CCHFV by infected ticks via bird migration. PMID:27308271

Application of Pulsed-Field Gel Electrophoresis and Binary Typing as Tools in Veterinary Clinical Microbiology and Molecular Epidemiologic Analysis of Bovine and Human Staphylococcus aureus Isolates

PubMed Central

Zadoks, Ruth; van Leeuwen, Willem; Barkema, Herman; Sampimon, Otlis; Verbrugh, Henri; Schukken, Ynte Hein; van Belkum, Alex

2000-01-01

Thirty-eight bovine mammary Staphylococcus aureus isolates from diverse clinical, temporal, and geographical origins were genotyped by pulsed-field gel electrophoresis (PFGE) after SmaI digestion of prokaryotic DNA and by means of binary typing using 15 strain-specific DNA probes. Seven pulsed-field types and four subtypes were identified, as were 16 binary types. Concordant delineation of genetic relatedness was documented by both techniques, yet based on practical and epidemiological considerations, binary typing was the preferable method. Genotypes of bovine isolates were compared to 55 previously characterized human S. aureus isolates through cluster analysis of binary types. Genetic clusters containing strains of both human and bovine origin were found, but bacterial genotypes were predominantly associated with a single host species. Binary typing proved an excellent tool for comparison of S. aureus strains, including methicillin-resistant S. aureus, derived from different host species and from different databases. For 28 bovine S. aureus isolates, detailed clinical observations in vivo were compared to strain typing results in vitro. Associations were found between distinct genotypes and severity of disease, suggesting strain-specific bacterial virulence. Circumstantial evidence furthermore supports strain-specific routes of bacterial dissemination. We conclude that PFGE and binary typing can be successfully applied for genetic analysis of S. aureus isolates from bovine mammary secretions. Binary typing in particular is a robust and simple method and promises to become a powerful tool for strain characterization, for resolution of clonal relationships of bacteria within and between host species, and for identification of sources and transmission routes of bovine S. aureus. PMID:10790124

The impact of MIG1 and/or MIG2 disruption on aerobic metabolism of succinate dehydrogenase negative Saccharomyces cerevisiae.

PubMed

Cao, Hailong; Yue, Min; Li, Shuguang; Bai, Xuefang; Zhao, Xiaoming; Du, Yuguang

2011-02-01

The zinc finger proteins Mig1 and Mig2 play important roles in glucose repression of Saccharomyces cerevisiae. To investigate whether the alleviation of glucose effect would result in an increase in aerobic succinate production, MIG1 and/or MIG2 were disrupted in a succinate dehydrogenase (SDH)-negative S. cerevisiae strain. Moreover, their impacts on physiology of the SDH-negative S. cerevisiae strain were studied under fully aerobic conditions when glucose was the sole carbon source. Our results showed that the succinate production for the SDH-negative S. cerevisiae was very low even under fully aerobic conditions. Furthermore, deletion of MIG1 and/or MIG2 did not result in an increase in succinate production in the SDH-negative S. cerevisiae strain. However, the synthesis of acetate was significantly affected by MIG1 deletion or in combination with MIG2 deletion. The acetate production for the mig1/mig2 double mutant BS2M was reduced by 69.72% compared to the parent strain B2S. In addition, the amount of ethanol produced by BS2M was slightly decreased. With the mig2 mutant BSM2, the concentrations of pyruvate and glycerol were increased by 26.23% and 15.28%, respectively, compared to the parent strain B2S.

Fastidious Gram-Negatives: Identification by the Vitek 2 Neisseria-Haemophilus Card and by Partial 16S rRNA Gene Sequencing Analysis.

PubMed

Sönksen, Ute Wolff; Christensen, Jens Jørgen; Nielsen, Lisbeth; Hesselbjerg, Annemarie; Hansen, Dennis Schrøder; Bruun, Brita

2010-12-31

Taxonomy and identification of fastidious Gram negatives are evolving and challenging. We compared identifications achieved with the Vitek 2 Neisseria-Haemophilus (NH) card and partial 16S rRNA gene sequence (526 bp stretch) analysis with identifications obtained with extensive phenotypic characterization using 100 fastidious Gram negative bacteria. Seventy-five strains represented 21 of the 26 taxa included in the Vitek 2 NH database and 25 strains represented related species not included in the database. Of the 100 strains, 31 were the type strains of the species. Vitek 2 NH identification results: 48 of 75 database strains were correctly identified, 11 strains gave `low discrimination´, seven strains were unidentified, and nine strains were misidentified. Identification of 25 non-database strains resulted in 14 strains incorrectly identified as belonging to species in the database. Partial 16S rRNA gene sequence analysis results: For 76 strains phenotypic and sequencing identifications were identical, for 23 strains the sequencing identifications were either probable or possible, and for one strain only the genus was confirmed. Thus, the Vitek 2 NH system identifies most of the commonly occurring species included in the database. Some strains of rarely occurring species and strains of non-database species closely related to database species cause problems. Partial 16S rRNA gene sequence analysis performs well, but does not always suffice, additional phenotypical characterization being useful for final identification.

Fastidious Gram-Negatives: Identification by the Vitek 2 Neisseria-Haemophilus Card and by Partial 16S rRNA Gene Sequencing Analysis

PubMed Central

Sönksen, Ute Wolff; Christensen, Jens Jørgen; Nielsen, Lisbeth; Hesselbjerg, Annemarie; Hansen, Dennis Schrøder; Bruun, Brita

2010-01-01

Taxonomy and identification of fastidious Gram negatives are evolving and challenging. We compared identifications achieved with the Vitek 2 Neisseria-Haemophilus (NH) card and partial 16S rRNA gene sequence (526 bp stretch) analysis with identifications obtained with extensive phenotypic characterization using 100 fastidious Gram negative bacteria. Seventy-five strains represented 21 of the 26 taxa included in the Vitek 2 NH database and 25 strains represented related species not included in the database. Of the 100 strains, 31 were the type strains of the species. Vitek 2 NH identification results: 48 of 75 database strains were correctly identified, 11 strains gave `low discrimination´, seven strains were unidentified, and nine strains were misidentified. Identification of 25 non-database strains resulted in 14 strains incorrectly identified as belonging to species in the database. Partial 16S rRNA gene sequence analysis results: For 76 strains phenotypic and sequencing identifications were identical, for 23 strains the sequencing identifications were either probable or possible, and for one strain only the genus was confirmed. Thus, the Vitek 2 NH system identifies most of the commonly occurring species included in the database. Some strains of rarely occurring species and strains of non-database species closely related to database species cause problems. Partial 16S rRNA gene sequence analysis performs well, but does not always suffice, additional phenotypical characterization being useful for final identification. PMID:21347215

Effect of strain on electronic and thermoelectric properties of few layers to bulk MoS₂.

PubMed

Bhattacharyya, Swastibrata; Pandey, Tribhuwan; Singh, Abhishek K

2014-11-21

The sensitive dependence of the electronic and thermoelectric properties of MoS₂ on applied strain opens up a variety of applications in the emerging area of straintronics. Using first-principles-based density functional theory calculations, we show that the band gap of a few layers of MoS₂ can be tuned by applying normal compressive (NC) strain, biaxial compressive (BC) strain, and biaxial tensile (BT) strain. A reversible semiconductor-to-metal transition (S-M transition) is observed under all three types of strain. In the case of NC strain, the threshold strain at which the S-M transition occurs increases when the number of layers increase and becomes maximum for the bulk. On the other hand, the threshold strain for the S-M transition in both BC and BT strains decreases when the number of layers increase. The difference in the mechanisms for the S-M transition is explained for different types of applied strain. Furthermore, the effect of both strain type and the number of layers on the transport properties are also studied using Botzmann transport theory. We optimize the transport properties as a function of the number of layers and the applied strain. 3L- and 2L-MoS₂ emerge as the most efficient thermoelectric materials under NC and BT strain, respectively. The calculated thermopower is large and comparable to some of the best thermoelectric materials. A comparison among the feasibility of these three types of strain is also discussed.

Characterization of Chicken Splenic-Derived Dendritic Cells Following Vaccine and Very Virulent Strains of Infectious Bursal Disease Virus Infection.

PubMed

Yasmin, A R; Yeap, S K; Hair-Bejo, M; Omar, A R

2016-12-01

Studies have shown that infectious bursal disease virus (IBDV) infects lymphoid cells, mainly B cells and macrophages. This study was aimed to examine the involvement of chicken splenic-derived dendritic cells (ch-sDCs) in specific-pathogen-free chickens following inoculation with IBDV vaccine strain (D78) and a very virulent (vv) strain (UPM0081). Following IBDV infection, enriched activated ch-sDCs were collected by using the negative selection method and were examined based on morphology and immunophenotyping to confirm the isolation method for dendritic cells (DCs). The presence of IBDV on enriched activated ch-sDCs was analyzed based on the immunofluorescence antibody test (IFAT), flow cytometry, and quantitative real-time PCR (RT-qPCR) while the mRNAs of several cytokines were detected using RT-qPCR. The isolated ch-sDCs resembled typical DC morphologies found in mammals by having a veiled shape and they grew in clusters. Meanwhile, the expression of DC maturation markers, namely CD86 and MHCII, were increased at day 2 and day 3 following vvIBDV and vaccine strain inoculation, respectively, ranging from 10% to 40% compared to the control at 2.55% (P < 0.05). At day 3 postinfection, IBDV VP3 proteins colocalized with CD86 were readily detected via IFAT and flow cytometry in both vaccine and vvIBDV strains. In addition, enriched activated ch-sDCs were also detected as positive based on the VP4 gene by RT-qPCR; however, a higher viral load was detected on vvIBDV compared to the vaccine group. Infection with vaccine and vvIBDV strains induced the enriched activated ch-sDCs to produce proinflammatory cytokines and Th1-like cytokines from day 3 onward; however, the expressions were higher in the vvIBDV group (P < 0.05). These data collectively suggest that enriched activated ch-sDCs were permissive to IBDV infection and produced a strong inflammatory and Th1-like cytokine response following vvIBDV infection as compared to the vaccine strain.

The MUT056399 Inhibitor of FabI Is a New Antistaphylococcal Compound▿

PubMed Central

Escaich, S.; Prouvensier, L.; Saccomani, M.; Durant, L.; Oxoby, M.; Gerusz, V.; Moreau, F.; Vongsouthi, V.; Maher, Kirsty; Morrissey, Ian; Soulama-Mouze, C.

2011-01-01

MUT056399 is a highly potent new inhibitor of the FabI enzyme of both Staphylococcus aureus and Escherichia coli. In vitro, MUT056399 was very active against S. aureus strains, including methicillin-susceptible S. aureus (MSSA), methicillin-resistant S. aureus (MRSA), linezolid-resistant, and multidrug-resistant strains, with MIC90s between 0.03 and 0.12 μg/ml. MUT056399 was also active against coagulase-negative staphylococci, with MIC90s between 0.12 and 4 μg/ml. The antibacterial spectrum is consistent with specific FabI inhibition with no activity against bacteria using FabK but activity against FabI-containing Gram-negative bacilli. In vitro, resistant clones of S. aureus were obtained at a low frequency. All of the resistant clones analyzed were found to contain mutations in the fabI gene. In vivo, MUT056399, administered subcutaneously, protected mice from a lethal systemic infection induced by MSSA, MRSA, and vancomycin-intermediate S. aureus strains (50% effective doses ranging from 19.3 mg/kg/day to 49.6 mg/kg/day). In the nonneutropenic murine thigh infection model, the same treatment with MUT056399 reduced the bacterial multiplication of MSSA and MRSA in the thighs of immunocompetent mice. These properties support MUT056399 as a very promising candidate for a novel drug to treat severe staphylococcal infections. PMID:21825292

Hospital strain colonization by Staphylococcus epidermidis.

PubMed

Blum-Menezes, D; Bratfich, O J; Padoveze, M C; Moretti, M L

2009-03-01

The skin and mucous membranes of healthy subjects are colonized by strains of Staphylococcus epidermidis showing a high diversity of genomic DNA polymorphisms. Prolonged hospitalization and the use of invasive procedures promote changes in the microbiota with subsequent colonization by hospital strains. We report here a patient with prolonged hospitalization due to chronic pancreatitis who was treated with multiple antibiotics, invasive procedures and abdominal surgery. We studied the dynamics of skin colonization by S. epidermidis leading to the development of catheter-related infections and compared the genotypic profile of clinical and microbiota strains by pulsed field gel electrophoresis. During hospitalization, the normal S. epidermidis skin microbiota exhibiting a polymorphic genomic DNA profile was replaced with a hospital-acquired biofilm-producer S. epidermidis strain that subsequently caused repetitive catheter-related infections.

Genomics, evolution, and molecular epidemiology of the Streptococcus bovis/Streptococcus equinus complex (SBSEC).

PubMed

Jans, Christoph; Meile, Leo; Lacroix, Christophe; Stevens, Marc J A

2015-07-01

The Streptococcus bovis/Streptococcus equinus complex (SBSEC) is a group of human and animal derived streptococci that are commensals (rumen and gastrointestinal tract), opportunistic pathogens or food fermentation associates. The classification of SBSEC has undergone massive changes and currently comprises 7 (sub)species grouped into four branches based on sequences identities: the Streptococcus gallolyticus, the Streptococcus equinus, the Streptococcus infantarius and the Streptococcus alactolyticus branch. In animals, SBSEC are causative agents for ruminal acidosis, potentially laminitis and infective endocarditis (IE). In humans, a strong association was established between bacteraemia, IE and colorectal cancer. Especially the SBSEC-species S. gallolyticus subsp. gallolyticus is an emerging pathogen for IE and prosthetic joint infections. S. gallolyticus subsp. pasteurianus and the S. infantarius branch are further associated with biliary and urinary tract infections. Knowledge on pathogenic mechanisms is so far limited to colonization factors such as pili and biofilm formation. Certain strain variants of S. gallolyticus subsp. macedonicus and S. infantarius subsp. infantarius are associated with traditional dairy and plant-based food fermentations and display traits suggesting safety. However, due to their close relationship to virulent strains, their use in food fermentation has to be critically assessed. Additionally, implementing accurate and up-to-date taxonomy is critical to enable appropriate treatment of patients and risk assessment of species and strains via recently developed multilocus sequence typing schemes to enable comparative global epidemiology. Comparative genomics revealed that SBSEC strains harbour genomics islands (GI) that seem acquired from other streptococci by horizontal gene transfer. In case of virulent strains these GI frequently encode putative virulence factors, in strains from food fermentation the GI encode functions that are pivotal for strain performance during fermentation. Comparative genomics is a powerful tool to identify acquired pathogenic functions, but there is still an urgent need for more physiological and epidemiological data to understand SBSEC-specific traits. Copyright © 2014 Elsevier B.V. All rights reserved.

Assessment of Liver Fibrosis Using Fast Strain-Encoded (FSENC) MRI Driven by Inherent Cardiac Motion

PubMed Central

Harouni, Ahmed A.; Gharib, Ahmed M.; Osman, Nael F.; Morse, Caryn; Heller, Theo; Abd-Elmoniem, Khaled Z.

2014-01-01

Purpose An external driver-free MRI method for assessment of liver fibrosis offers a promising non-invasive tool for diagnosis and monitoring of liver disease. Lately, the heart’s intrinsic motion and MR tagging have been utilized for the quantification of liver strain. However, MR tagging requires multiple breath-hold acquisitions and substantial post-processing. This work proposes a fast strain-encoded (FSENC) MRI methodology to measure the peak strain (Sp) in the liver’s left lobe, which is in close proximity and caudal to the heart. Additionally, a new method is introduced to measure heart-induced shear wave velocity (SWV) inside the liver. Methods Phantom and in-vivo experiments (11 healthy subjects, and 11 patients with liver fibrosis) were conducted. Reproducibility experiments were performed in seven healthy subjects. Results Peak liver strain Sp significantly decreased in fibrotic liver compared healthy liver (6.46%±2.27% vs. 12.49%±1.76%, P<0.05). Heart-induced SWV significantly increased in patients compared to healthy subjects (0.15±0.04 m/s vs. 0.63±0.32 m/s, P<0.05). Reproducibility analysis yielded no significant difference in Sp (P=0.47) or SWV (P=0.56). Conclusion Accelerated external driver-free noninvasive assessment of left liver lobe strain and shear wave velocity is feasible using strain-encoded MRI. The two measures significantly separate healthy subjects from patients with fibrotic liver. PMID:25081734

Transesophageal Echocardiography, 3-Dimensional and Speckle Tracking Together as Sensitive Markers for Early Outcome in Patients With Left Ventricular Dysfunction Undergoing Cardiac Surgery.

PubMed

Kumar, Alok; Puri, Goverdhan Dutt; Bahl, Ajay

2017-10-01

Speckle tracking, when combined with 3-dimensional (3D) left ventricular ejection fraction, might prove to be a more sensitive marker for postoperative ventricular dysfunction. This study investigated early outcomes in a cohort of patients with left ventricular dysfunction undergoing cardiac surgery. Prospective, blinded, observational study. University hospital; single institution. The study comprised 73 adult patients with left ventricular ejection fraction <50% undergoing cardiac surgery using cardiopulmonary bypass. Routine transesophageal echocardiography before and after bypass. Global longitudinal strain using speckle tracking and 3D left ventricular ejection fraction were computed using transesophageal echocardiography. Mean prebypass global longitudinal strain and 3D left ventricle ejection fraction were significantly lower in patients with postoperative low-cardiac-output syndrome compared with patients who did not develop low cardiac output (global longitudinal strain -7.5% v -10.7% and 3D left ventricular ejection fraction 29% v 39%, respectively; p < 0.0001). The cut-off value of global longitudinal strain predicting postoperative low-cardiac-output syndrome was -6%, with 95% sensitivity and 68% specificity; and 3D left ventricular ejection fraction was 19% with 98% sensitivity and 81% specificity. Preoperative left ventricular global longitudinal strain (-6%) and 3D left ventricular ejection fraction (19%) together could act as predictor of postoperative low-cardiac-output states with high sensitivity (99.9%) in patients undergoing cardiac surgery. Copyright © 2017 Elsevier Inc. All rights reserved.

Prevalence of Streptococcus suis Genotypes in Wild Boars of Northwestern Germany▿

PubMed Central

Baums, Christoph G.; Verkühlen, Gerd Josef; Rehm, Thomas; Silva, Luciana M. G.; Beyerbach, Martin; Pohlmeyer, Klaus; Valentin-Weigand, Peter

2007-01-01

Invasive serotype 2 (cps2+) strains of Streptococcus suis cause meningitis in pigs and humans. Four case reports of S. suis meningitis in hunters suggest transmission of S. suis through the butchering of wild boars. Therefore, the objective of this study was to investigate the prevalence of potentially human-pathogenic S. suis strains in wild boars. S. suis was isolated from 92% of all tested tonsils (n = 200) from wild boars. A total of 244 S. suis isolates were genotyped using PCR assays for the detection of serotype-specific genes, the hemolysin gene sly, and the virulence-associated genes mrp and epf. The prevalence of the cps2+ genotype among strains from wild boars was comparable to that of control strains from domestic pig carriers. Ninety-five percent of the cps2+ wild boar strains were positive for mrp, sly, and epf*, the large variant of epf. Interestingly, epf* was significantly more frequently detected in cps2+ strains from wild boars than in those from domestic pigs; epf* is also typically found in European S. suis isolates from humans, including a meningitis isolate from a German hunter. These results suggest that at least 10% of wild boars in Northwestern Germany carry S. suis strains that are potentially virulent in humans. Additional amplified fragment length polymorphism analysis supported this hypothesis, since homogeneous clustering of the epf* mrp+ sly+ cps2+ strains from wild boars with invasive human and porcine strains was observed. PMID:17085699

Prevalence of Streptococcus suis genotypes in wild boars of Northwestern Germany.

PubMed

Baums, Christoph G; Verkühlen, Gerd Josef; Rehm, Thomas; Silva, Luciana M G; Beyerbach, Martin; Pohlmeyer, Klaus; Valentin-Weigand, Peter

2007-02-01

Invasive serotype 2 (cps2+) strains of Streptococcus suis cause meningitis in pigs and humans. Four case reports of S. suis meningitis in hunters suggest transmission of S. suis through the butchering of wild boars. Therefore, the objective of this study was to investigate the prevalence of potentially human-pathogenic S. suis strains in wild boars. S. suis was isolated from 92% of all tested tonsils (n=200) from wild boars. A total of 244 S. suis isolates were genotyped using PCR assays for the detection of serotype-specific genes, the hemolysin gene sly, and the virulence-associated genes mrp and epf. The prevalence of the cps2+ genotype among strains from wild boars was comparable to that of control strains from domestic pig carriers. Ninety-five percent of the cps2+ wild boar strains were positive for mrp, sly, and epf*, the large variant of epf. Interestingly, epf* was significantly more frequently detected in cps2+ strains from wild boars than in those from domestic pigs; epf* is also typically found in European S. suis isolates from humans, including a meningitis isolate from a German hunter. These results suggest that at least 10% of wild boars in Northwestern Germany carry S. suis strains that are potentially virulent in humans. Additional amplified fragment length polymorphism analysis supported this hypothesis, since homogeneous clustering of the epf* mrp+ sly+ cps2+ strains from wild boars with invasive human and porcine strains was observed.

Species Identification and Virulence Attributes of Saccharomyces boulardii (nom. inval.)

PubMed Central

McCullough, Michael J.; Clemons, Karl V.; McCusker, John H.; Stevens, David A.

1998-01-01

Saccharomyces boulardii (nom. inval.) has been used for the treatment of several types of diarrhea. Recent studies have confirmed that S. boulardii is effective in the treatment of diarrhea, in particular chronic or recurrent diarrhea, and furthermore that it is a safe and well-tolerated treatment. The aim of the present study was to identify strains of S. boulardii to the species level and assess their virulence in established murine models. Three strains of S. boulardii were obtained from commercially available products in France and Italy. The three S. boulardii strains did not form spores upon repeated testing. Therefore, classical methods used for the identification of Saccharomyces spp. could not be undertaken. Typing by using the restriction fragment length polymorphisms (RFLPs) of the PCR-amplified intergenic transcribed spacer regions (including the 5.8S ribosomal DNA) showed that the three isolates of S. boulardii were not separable from authentic isolates of Saccharomyces cerevisiae with any of the 10 restriction endonucleases assessed, whereas 9 of the 10 recognized species of Saccharomyces could be differentiated. RFLP analysis of cellular DNA with EcoRI showed that all three strains of S. boulardii had identical patterns and were similar to other authentic S. cerevisiae isolates tested. Therefore, the commercial strains of S. boulardii available to us cannot be genotypically distinguished from S. cerevisiae. Two S. boulardii strains were tested in CD-1 and DBA/2N mouse models of systemic disease and showed intermediate virulence compared with virulent and avirulent strains of S. cerevisiae. The results of the present study show that these S. boulardii strains are asporogenous strains of the species S. cerevisiae, not representatives of a distinct and separate species, and possess moderate virulence in murine models of systemic infection. Therefore, caution should be advised in the clinical use of these strains in immunocompromised patients until further study is undertaken. PMID:9705402

Right ventricular speckle tracking assessment for differentiation of pressure- versus volume-overloaded right ventricle.

PubMed

Werther Evaldsson, Anna; Ingvarsson, Annika; Waktare, Johan; Smith, Gustav J; Thilén, Ulf; Stagmo, Martin; Roijer, Anders; Rådegran, Goran; Meurling, Carl

2017-10-26

Right ventricular (RV) dysfunction may be caused by either pressure or volume overload. RV function is conventionally assessed with echocardiography using tricuspid annular plane systolic excursion (TAPSE), RV fractional area change (RVFAC), tricuspid lateral annular systolic velocity (S') and RV index of myocardial performance (RIMP). The purpose of this study was to evaluate whether RV global longitudinal strain (RVGLS) and RV-free wall strain (RV-free) could add additional information to differentiate these two causes of RV overload. The study enrolled 89 patients with an echocardiographic trans-tricuspid gradient >30 mmHg. Forty-five patients with pulmonary arterial hypertension or chronic thromboembolic pulmonary hypertension (pressure overload) were compared with 44 patients with an atrial septum defect (volume overload). RV size was larger in the volume group (P<0·05). TAPSE and S' were lower in the pressure group (P<0·05, P<0·01). RVFAC was lower in the pressure group (P<0·001) as well as RVGLS (-12·1 ± 3·3% versus -20·2 ± 3·4%, P<0·001) and RV-free (-12·9 ± 3·3% versus -19·4 ± 3·4%, P<0·001). In this study, RVGLS and RV-free could more accurately discriminate RV pressure from volume overload than conventional measures. The reason could be that TAPSE and S' are unable to differentiate active deformation from passive entrainment caused by the left ventricle. The pressure group had evidence of marked RV hypertrophy despite standard functional parameters (TAPSE and S) within normal range. This would enhance the value of strain to more sensitively detect abnormal function. A cut-off value of below -16% for RVGLS and RV-free predicts RV pressure overload with high accuracy. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Profile of Shiga toxin-producing Escherichia coli strains isolated from dogs and cats and genetic relationships with isolates from cattle, meat and humans.

PubMed

Bentancor, A; Rumi, M V; Carbonari, C; Gerhardt, E; Larzábal, M; Vilte, D A; Pistone-Creydt, V; Chinen, I; Ibarra, C; Cataldi, A; Mercado, E C

2012-05-04

Pets can be reservoirs of Shiga toxin-producing Escherichia coli (STEC) strains. The aim of this study was to examine nine strains belonging to several serotypes (O91:H21, O91:H16, O178:H19, O8:H19, O22:H8, O22:HNT, ONT:H8), previously recovered from cats or dogs. To this end, we assessed a set of additional virulence genes (stx(2) subtype, subAB, ehxA, eae and saa), cytotoxic activity, and genetic relationships with strains isolated from cattle, meat and humans using pulsed-field gel electrophoresis (PFGE). Most of the isolates carried the stx(2) and/or stx(2vh-b) sequences, while only the O91:H21 isolate presented the mucus-activatable stx(2d) variant, as confirmed by sequencing the genes of subunits A and B. All the strains showed cytotoxic activity in cultured cells. One of the two O178:H19, selected for its high level of cytotoxicity in Vero cells, showed the ability to cause functional alterations in the human colon mucosa in vitro. None of the strains possessed the subAB, eae or saa genes and only the strains belonging to serotype O8:H19 carried the ehxA gene. The isolates shared 90-100% similarity by PFGE to epidemiologically unrelated strains of the corresponding serotypes recovered from cattle, meat or humans. Our results demonstrate that dogs and cats may have a role in the infection of humans by STEC, probably serving as a vehicle for bovine strains in the cycle of human infection, and thus emphasize the health risks for owners and their families. Copyright © 2011 Elsevier B.V. All rights reserved.

Comparing in vitro and in vivo virulence phenotypes of Burkholderia pseudomallei type G strains.

PubMed

Lewis, Eric R G; Kilgore, Paul B; Mott, Tiffany M; Pradenas, Gonzalo A; Torres, Alfredo G

2017-01-01

Burkholderia pseudomallei (Bpm) is a saprophytic rod-shaped gram-negative bacterium and the causative agent of melioidosis. This disease has previously been described as endemic in areas such as northern Australia and Southeast Asia, but, more recently, a better understanding of the epidemiology of melioidosis indicated that the disease is distributed worldwide, including regions of the Americas and Africa. A 16S-23S rDNA internal transcribed spacer (ITS) typing system has been developed for Bpm and has revealed that ITS types C, E, and hybrid CE are mainly associated with Australia and Southeast Asia while type G strains are more associated with cases of melioidosis in the Western Hemisphere. The purpose of the current study was to determine the in vitro and in vivo virulence profiles of the understudied Bpm type G strains Ca2009, Ca2013a, Mx2013, and 724644 and compared such phenotypes to the commonly studied Bpm type C strain K96243. We evaluated virulence by measuring invasion/uptake and survival of these Bpm strains in murine respiratory epithelial LA-4 cells and alveolar macrophage MH-S cells using different multiplicity of infections (MOIs of 1 and 10). We also calculated the lethal dose 50 values (LD50) in BALB/c mice that were inoculated intranasally with either Ca2009, Ca2013a, or Mx2013. Overall, the virulence and lethality phenotypes of Bpm type G strains were similar to the Bpm type C strain K96243. Additional comparative analyses between the Bpm ITS types may lead to a better understanding of the contribution of the ITS type to the epidemiology and ecology of Bpm strains.

Comparing in vitro and in vivo virulence phenotypes of Burkholderia pseudomallei type G strains

PubMed Central

Mott, Tiffany M.; Pradenas, Gonzalo A.

2017-01-01

Burkholderia pseudomallei (Bpm) is a saprophytic rod-shaped gram-negative bacterium and the causative agent of melioidosis. This disease has previously been described as endemic in areas such as northern Australia and Southeast Asia, but, more recently, a better understanding of the epidemiology of melioidosis indicated that the disease is distributed worldwide, including regions of the Americas and Africa. A 16S-23S rDNA internal transcribed spacer (ITS) typing system has been developed for Bpm and has revealed that ITS types C, E, and hybrid CE are mainly associated with Australia and Southeast Asia while type G strains are more associated with cases of melioidosis in the Western Hemisphere. The purpose of the current study was to determine the in vitro and in vivo virulence profiles of the understudied Bpm type G strains Ca2009, Ca2013a, Mx2013, and 724644 and compared such phenotypes to the commonly studied Bpm type C strain K96243. We evaluated virulence by measuring invasion/uptake and survival of these Bpm strains in murine respiratory epithelial LA-4 cells and alveolar macrophage MH-S cells using different multiplicity of infections (MOIs of 1 and 10). We also calculated the lethal dose 50 values (LD50) in BALB/c mice that were inoculated intranasally with either Ca2009, Ca2013a, or Mx2013. Overall, the virulence and lethality phenotypes of Bpm type G strains were similar to the Bpm type C strain K96243. Additional comparative analyses between the Bpm ITS types may lead to a better understanding of the contribution of the ITS type to the epidemiology and ecology of Bpm strains. PMID:28414823

Toll-like receptor 2-independent host innate immune response against an epidemic strain of Streptococcus suis that causes a toxic shock-like syndrome in humans.

PubMed

Lachance, Claude; Segura, Mariela; Gerber, Pehuén Pereyra; Xu, Jianguo; Gottschalk, Marcelo

2013-01-01

Streptococcus suis is an emerging zoonotic agent causing meningitis and septicemia. Outbreaks in humans in China with atypical cases of streptococcal toxic shock-like syndrome have been described to be caused by a clonal epidemic S. suis strain characterized as sequence type (ST) 7 by multilocus sequence typing, different from the classical ST1 usually isolated in Europe. Previous in vitro studies showed that Toll-like receptor (TLR) 2 plays a major role in S. suis ST1 interactions with host cells. In the present study, the in vivo role of TLR2 in systemic infections caused by S. suis ST1 or ST7 strains using TLR2 deficient (TLR2(-/-)) mice was evaluated. TLR2-mediated recognition significantly contributes to the acute disease caused by the highly virulent S. suis ST1 strain, since the TLR2(-/-) mice remained unaffected when compared to wild type (WT) mice. The lack of mortality could not be associated with a lower bacterial burden; however, a significant decrease in the induction of pro-inflammatory mediators, as evaluated by microarray, real-time PCR and protein assays, was observed. On the other hand, TLR2(-/-) mice infected with the epidemic ST7 strain presented no significant differences regarding survival and expression of pro-inflammatory mediators when compared to the WT mice. Together, these results show a TLR2-independent host innate immune response to S. suis that depends on the strain.

Improvement of the Texture of Yogurt by Use of Exopolysaccharide Producing Lactic Acid Bacteria

PubMed Central

Han, Xue; Yang, Zhe; Jing, Xueping; Yu, Peng; Zhang, Yingchun

2016-01-01

19 Streptococcus thermophilus with high exopolysaccharide production were isolated from traditional Chinese fermented dairy products. The exopolysaccharide and viscosity of milk fermented by these 19 isolates were assayed. The strains of Streptococcus thermophilus zlw TM11 were selected because its fermented milk had the highest exopolysaccharide content (380 mg/L) and viscosity (7716 mpa/s). Then Streptococcus thermophilus zlw TM11 was combined with Lactobacillus delbrueckii subsp. bulgaricus 3 4.5 and the combination was named SH-1. The quality of the yogurt fermented by SH-1 and two commercial starter cultures (YO-MIX 465, YF-L711) were compared. It was shown that the exopolysaccharide content of yogurt fermented by SH-1 was similar to that of yogurt fermented by YF-L711 and significantly higher than YO-MIX 465 (p < 0.05). In addition, the yogurt fermented by SH-1 had the lowest syneresis (8.5%) and better texture and sensory than the samples fermented by YO-MIX 465 and YF-L711. It manifested that the selected higher exopolysaccharide production starter SH-1 could be used as yogurt starter and reduce the amount of adding stabilizer, which can compare with the imported commercial starter culture. PMID:27294135

Presence of antioxidative agent, Pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro- in newly isolated Streptomyces mangrovisoli sp. nov.

PubMed Central

Ser, Hooi-Leng; Palanisamy, Uma D.; Yin, Wai-Fong; Abd Malek, Sri N.; Chan, Kok-Gan; Goh, Bey-Hing; Lee, Learn-Han

2015-01-01

A novel Streptomyces, strain MUSC 149T was isolated from mangrove soil. A polyphasic approach was used to study the taxonomy of MUSC 149T, which shows a range of phylogenetic and chemotaxonomic properties consistent with those of the members of the genus Streptomyces. The diamino acid of the cell wall peptidoglycan was LL-diaminopimelic acid. The predominant menaquinones were identified as MK9(H8) and MK9(H6). Phylogenetic analysis indicated that closely related strains include Streptomyces rhizophilus NBRC 108885T (99.2% sequence similarity), S. gramineus NBRC 107863T (98.7%) and S. graminisoli NBRC 108883T (98.5%). The DNA–DNA relatedness values between MUSC 149T and closely related type strains ranged from 12.4 ± 3.3% to 27.3 ± 1.9%. The DNA G + C content was determined to be 72.7 mol%. The extract of MUSC 149T exhibited strong antioxidant activity and chemical analysis reported identification of an antioxidant agent, Pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-. These data showed that metabolites of MUSC 149T shall be useful as preventive agent against free-radical associated diseases. Based on the polyphasic study of MUSC 149T, the strain merits assignment to a novel species, for which the name S. mangrovisoli sp. nov. is proposed. The type strain is MUSC 149T (=MCCC 1K00699T=DSM 100438T). PMID:26347733

Genotyping of Indian antigenic, vaccine, and field Brucella spp. using multilocus sequence typing.

PubMed

Shome, Rajeswari; Krithiga, Natesan; Shankaranarayana, Padmashree B; Jegadesan, Sankarasubramanian; Udayakumar S, Vishnu; Shome, Bibek Ranjan; Saikia, Girin Kumar; Sharma, Narendra Kumar; Chauhan, Harshad; Chandel, Bharat Singh; Jeyaprakash, Rajendhran; Rahman, Habibur

2016-03-31

Brucellosis is one of the most important zoonotic diseases that affects multiple livestock species and causes great economic losses. The highly conserved genomes of Brucella, with > 90% homology among species, makes it important to study the genetic diversity circulating in the country. A total of 26 Brucella spp. (4 reference strains and 22 field isolates) and 1 B. melitensis draft genome sequence from India (B. melitensis Bm IND1) were included for sequence typing. The field isolates were identified by biochemical tests and confirmed by both conventional and quantitative polymerase chain reaction (qPCR) targeting bcsp 31Brucella genus-specific marker. Brucella speciation and biotyping was done by Bruce ladder, probe qPCR, and AMOS PCRs, respectively, and genotyping was done by multilocus sequence typing (MLST). The MLST typing of 27 Brucella spp. revealed five distinct sequence types (STs); the B. abortus S99 reference strain and 21 B. abortus field isolates belonged to ST1. On the other hand, the vaccine strain B. abortus S19 was genotyped as ST5. Similarly, B. melitensis 16M reference strain and one B. melitensis field isolate were grouped into ST7. Another B. melitensis field isolate belonged to ST8 (draft genome sequence from India), and only B. suis 1330 reference strain was found to be ST14. The sequences revealed genetic similarity of the Indian strains to the global reference and field strains. The study highlights the usefulness of MLST for typing of field isolates and validation of reference strains used for diagnosis and vaccination against brucellosis.

Comparative Genomics of Ricketttsia prowazekii Madrid E and Breinl Strains

DTIC Science & Technology

2004-01-01

natural exposure to antibiotic -resistant strains and the use of laboratory-manipulated strains as bio- logical warfare agents (28). The World Health...tussis, in the Cag system in Helicobacter pylori, and in the icm/dot system in Legionella pneumophila (reference 12 and references therein). However, the...transfer by the virulence system of Legionella pneumophila. Science 279:873– 876. 45. Waghela, S. D., F. R. Rurangirwa, S. M. Mahan, C. E. Yunker, T. B

Probiotic Potential of Lactobacillus Strains with Antimicrobial Activity against Some Human Pathogenic Strains

PubMed Central

Shokryazdan, Parisa; Sieo, Chin Chin; Kalavathy, Ramasamy; Liang, Juan Boo; Alitheen, Noorjahan Banu; Faseleh Jahromi, Mohammad; Ho, Yin Wan

2014-01-01

The objective of this study was to isolate, identify, and characterize some lactic acid bacterial strains from human milk, infant feces, and fermented grapes and dates, as potential probiotics with antimicrobial activity against some human pathogenic strains. One hundred and forty bacterial strains were isolated and, after initial identification and a preliminary screening for acid and bile tolerance, nine of the best isolates were selected and further identified using 16 S rRNA gene sequences. The nine selected isolates were then characterized in vitro for their probiotic characteristics and their antimicrobial activities against some human pathogens. Results showed that all nine isolates belonged to the genus Lactobacillus. They were able to tolerate pH 3 for 3 h, 0.3% bile salts for 4 h, and 1.9 mg/mL pancreatic enzymes for 3 h. They exhibited good ability to attach to intestinal epithelial cells and were not resistant to the tested antibiotics. They also showed good antimicrobial activities against the tested pathogenic strains of humans, and most of them exhibited stronger antimicrobial activity than the reference strain L. casei Shirota. Thus, the nine Lactobacillus strains could be considered as potential antimicrobial probiotic strains against human pathogens and should be further studied for their human health benefits. PMID:25105147

Strain distribution in the lumbar vertebrae under different loading configurations.

PubMed

Cristofolini, Luca; Brandolini, Nicola; Danesi, Valentina; Juszczyk, Mateusz M; Erani, Paolo; Viceconti, Marco

2013-10-01

The stress/strain distribution in the human vertebrae has seldom been measured, and only for a limited number of loading scenarios, at few locations on the bone surface. This in vitro study aimed at measuring how strain varies on the surface of the lumbar vertebral body and how such strain pattern depends on the loading conditions. Eight cadaveric specimens were instrumented with eight triaxial strain gauges each to measure the magnitude and direction of principal strains in the vertebral body. Each vertebra was tested in a three adjacent vertebrae segment fashion. The loading configurations included a compressive force aligned with the vertebral body but also tilted (15°) in each direction in the frontal and sagittal planes, a traction force, and torsion (both directions). Each loading configuration was tested six times on each specimen. The strain magnitude varied significantly between strain measurement locations. The strain distribution varied significantly when different loading conditions were applied (compression vs. torsion vs. traction). The strain distribution when the compressive force was tilted by 15° was also significantly different from the axial compression. Strains were minimal when the compressive force was applied coaxial with the vertebral body, compared with all other loading configurations. Also, strain was significantly more uniform for the axial compression, compared with all other loading configurations. Principal strains were aligned within 19° to the axis of the vertebral body for axial-compression and axial-traction. Conversely, when the applied force was tilted by 15°, the direction of principal strain varied by a much larger angle (15° to 28°). This is the first time, to our knowledge, that the strain distribution in the vertebral body is measured for such a variety of loading configurations and a large number of strain sensors. The present findings suggest that the structure of the vertebral body is optimized to sustain compressive forces, whereas even a small tilt angle makes the vertebral structure work under suboptimal conditions. Copyright © 2013 Elsevier Inc. All rights reserved.

Utilization of Sugarcane Bagasse by Halogeometricum borinquense Strain E3 for Biosynthesis of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)

PubMed Central

Salgaonkar, Bhakti B.; Bragança, Judith M.

2017-01-01

Sugarcane bagasse (SCB), one of the major lignocellulosic agro-industrial waste products, was used as a substrate for biosynthesis of polyhydroxyalkanoates (PHA) by halophilic archaea. Among the various wild-type halophilic archaeal strains screened, Halogeometricum borinquense strain E3 showed better growth and PHA accumulation as compared to Haloferaxvolcanii strain BBK2, Haloarcula japonica strain BS2, and Halococcus salifodinae strain BK6. Growth kinetics and bioprocess parameters revealed the maximum PHA accumulated by strain E3 to be 50.4 ± 0.1 and 45.7 ± 0.19 (%) with specific productivity (qp) of 3.0 and 2.7 (mg/g/h) using NaCl synthetic medium supplemented with 25% and 50% SCB hydrolysate, respectively. PHAs synthesized by strain E3 were recovered in chloroform using a Soxhlet apparatus. Characterization of the polymer using crotonic acid assay, X-ray diffraction (XRD), differential scanning calorimeter (DSC), Fourier transform infrared (FT-IR), and proton nuclear magnetic resonance (1H-NMR) spectroscopy analysis revealed the polymer obtained from SCB hydrolysate to be a co-polymer of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] comprising of 13.29 mol % 3HV units. PMID:28952529

Left Ventricular Myocardial Function in Children With Pulmonary Hypertension: Relation to Right Ventricular Performance and Hemodynamics.

PubMed

Burkett, Dale A; Slorach, Cameron; Patel, Sonali S; Redington, Andrew N; Ivy, D Dunbar; Mertens, Luc; Younoszai, Adel K; Friedberg, Mark K

2015-08-01

Through ventricular interdependence, pulmonary hypertension (PH) induces left ventricular (LV) dysfunction. We hypothesized that LV strain/strain rate, surrogate measures of myocardial contractility, are reduced in pediatric PH and relate to invasive hemodynamics, right ventricular strain, and functional measures of PH. At 2 institutions, echocardiography was prospectively performed in 54 pediatric PH patients during cardiac catheterization, and in 54 matched controls. Patients with PH had reduced LV global longitudinal strain (LS; -18.8 [-17.3 to -20.4]% versus -20.2 [-19.0 to -20.9]%; P=0.0046) predominantly because of reduced basal (-12.9 [-10.8 to -16.3]% versus -17.9 [-14.5 to -20.7]%; P<0.0001) and mid (-17.5 [-15.5 to -19.0]% versus -21.1 [-19.1 to -23.0]%; P<0.0001) septal strain. Basal global circumferential strain was reduced (-18.7 [-15.7 to -22.1]% versus -20.6 [-19.0 to -22.5]%; P=0.0098), as were septal and free-wall segments. Mid circumferential strain was reduced within the free-wall. Strain rates were reduced in similar patterns. Basal septum LS, the combined average LS of basal and mid interventricular septal segments, correlated strongly with degree of PH (r=0.66; P<0.0001), pulmonary vascular resistance (r=0.60; P<0.0001), and right ventricular free-wall LS (r=0.64; P<0.0001). Brain natriuretic peptide levels correlated moderately with septal LS (r=0.48; P=0.0038). PH functional class correlated moderately with LV free-wall LS (r=-0.48; P=0.0051). The septum, shared between ventricles and affected by septal shift, was the most affected LV region in PH. Pediatric PH patients demonstrate reduced LV strain/strain rate, predominantly within the septum, with relationships to invasive hemodynamics, right ventricular strain, and functional PH measures. © 2015 American Heart Association, Inc.

Organic acids for control of Salmonella in different feed materials

PubMed Central

2013-01-01

Background Salmonella control in animal feed is important in order to protect animal and public health. Organic acids is one of the control measures used for treatment of Salmonella contaminated feed or feed ingredients. In the present study, the efficacy of formic acid (FA) and different blends of FA, propionic acid (PA) and sodium formate (SF) was investigated. Four Salmonella strains isolated from feed were assayed for their acid tolerance. Also, the effect of lower temperatures (5°C and 15°C) compared to room temperature was investigated in rape seed and soybean meal. Results The efficacy of acid treatments varied significantly between different feed materials. The strongest reduction was seen in pelleted and compound mash feed (2.5 log10 reduction) followed by rapeseed meal (1 log10 reduction) after 5 days exposure. However, in soybean meal the acid effects were limited (less than 0.5 log10 reduction) even after several weeks’ exposure. In all experiments the survival curves showed a concave shape, with a fast initial death phase followed by reduction at a slower rate during the remaining time of the experiment. No difference in Salmonella reduction was observed between FA and a blend of FA and PA, whereas a commercial blend of FA and SF (Amasil) was slightly more efficacious (0.5-1 log10 reduction) than a blend of FA and PA (Luprocid) in compound mash feed. The Salmonella Infantis strain was found to be the most acid tolerant strain followed by, S. Putten, S. Senftenberg and S. Typhimurium. The tolerance of the S. Infantis strain compared with the S. Typhimurium strain was statistically significant (p<0.05). The lethal effect of FA on the S. Typhimurium strain and the S. Infantis strain was lower at 5°C and 15°C compared to room temperatures. Conclusions Acid treatment of Salmonella in feed is a matter of reducing the number of viable bacterial cells rather than eliminating the organism. Recommendations on the use of acids for controlling Salmonella in feed should take into account the relative efficacy of acid treatment in different feed materials, the variation in acid tolerance between different Salmonella strains, and the treatment temperature. PMID:23597100

High-throughput screening of high Monascus pigment-producing strain based on digital image processing.

PubMed

Xia, Meng-lei; Wang, Lan; Yang, Zhi-xia; Chen, Hong-zhang

2016-04-01

This work proposed a new method which applied image processing and support vector machine (SVM) for screening of mold strains. Taking Monascus as example, morphological characteristics of Monascus colony were quantified by image processing. And the association between the characteristics and pigment production capability was determined by SVM. On this basis, a highly automated screening strategy was achieved. The accuracy of the proposed strategy is 80.6 %, which is compatible with the existing methods (81.1 % for microplate and 85.4 % for flask). Meanwhile, the screening of 500 colonies only takes 20-30 min, which is the highest rate among all published results. By applying this automated method, 13 strains with high-predicted production were obtained and the best one produced as 2.8-fold (226 U/mL) of pigment and 1.9-fold (51 mg/L) of lovastatin compared with the parent strain. The current study provides us with an effective and promising method for strain improvement.

Natural exopolysaccharides enhance survival of lactic acid bacteria in frozen dairy desserts.

PubMed

Hong, S H; Marshall, R T

2001-06-01

Viable lactic acid-producing bacteria in frozen dairy desserts can be a source of beta-galactosidase for persons who absorb lactose insufficiently. However, freezing kills many of the cells, causing loss of enzymatic activity. Cultures selected for high beta-galactosidase activities and high survival rates in the presence of bile were examined for survivability during freezing in reduced-fat ice cream. Encapsulated S. thermophilus strains survived better than their nonencapsulated mutants in reduced-fat ice cream after freezing and frozen storage at -29 degrees C for 16 d (28 vs. 19%). However, a small nonencapsulated strain of Lactobacillus delbrueckii sp. bulgaricus survived better than the large encapsulated strain in reduced-fat ice cream. Factors that improved survival of encapsulated S. thermophilus 1068 in ice cream were 1) harvest of cells in the late-log phase of growth at 37 degrees C rather than at 40, 42.5, or 45 degrees C; 2) overrun at 50% rather than 100%; and 3) storage at -17 degrees C rather than -23 or -29 degrees C. Survival of strain ST1068 was unaffected by 1) neutralization of acid during growth or 2) substitution of nitrogen for air in building overrun.

Burkholderia paludis sp. nov., an Antibiotic-Siderophore Producing Novel Burkholderia cepacia Complex Species, Isolated from Malaysian Tropical Peat Swamp Soil.

PubMed

Ong, Kuan Shion; Aw, Yoong Kit; Lee, Learn Han; Yule, Catherine M; Cheow, Yuen Lin; Lee, Sui Mae

2016-01-01

A novel Gram negative rod-shaped bacterium, designated strain MSh1 T , was isolated from Southeast Pahang tropical peat swamp forest soil in Malaysia and characterized using a polyphasic taxonomy approach. The predominant cellular fatty acids (>10.0%) were C 16:0 (31.7%), C 17:0 cyclo (26.6%), and C 19:0 cyclo ω8c (16.1%). The polar lipids detected were phosphatidylglycerol, phosphatidylethanolamine, and diphosphatidylglycerol. The predominant ubiquinone was Q-8. This revealed that strain MSh1 T belongs to the genus Burkholderia . The type strain MSh1 T can be differentiated from other Burkholderia cepacia complex (Bcc) species by phylogenetic analysis of 16S rRNA gene sequence, multilocus sequence analysis (MLSA), average nucleotide identity (ANI) and biochemical tests. DNA-DNA relatedness values between strain MSh1 T and closely related type strains were below the 70% threshold value. Based on this polyphasic study of MSh1 T , it can be concluded that this strain represents a novel species within the Bcc, for which the name Burkholderia paludis sp. nov. is proposed. The type strain is MSh1 T (= DSM 100703 T = MCCC 1K01245 T ). The dichloromethane extract of MSh1 T exhibited antimicrobial activity against four Gram positive bacteria ( Enterococcus faecalis ATCC 29212, E. faecalis ATCC 700802, Staphylococcus aureus ATCC 29213, S. aureus ATCC 700699) and a Gram negative bacteria ( Escherichia coli ATCC 25922). Further purification work has led to the isolation of Compound 1, pyochelin. Pyochelin demonstrated antimicrobial activity against four S. aureus strains and three E . faecalis strains with MIC-values of 3.13 μg/ml and 6.26 μg/ml, respectively. SEM analysis showed that the cellular morphology of E. faecalis ATCC 700802 was not affected by pyochelin; suggesting that it might target the intracellular components. Pyochelin, a siderophore with antimicrobial activity might be useful in treating bacterial infections caused by S. aureus and E. faecalis , however further work has to be done.

Efficacy of a trivalent influenza vaccine against seasonal strains and against 2009 pandemic H1N1: A randomized, placebo-controlled trial.

PubMed

Mcbride, William J H; Abhayaratna, Walter P; Barr, Ian; Booy, Robert; Carapetis, Jonathan; Carson, Simon; De Looze, Ferdinandus; Ellis-Pegler, Rod; Heron, Leon; Karrasch, Jeff; Marshall, Helen; Mcvernon, Jodie; Nolan, Terry; Rawlinson, William; Reid, Jim; Richmond, Peter; Shakib, Sepehr; Basser, Russell L; Hartel, Gunter F; Lai, Michael H; Rockman, Steven; Greenberg, Michael E

2016-09-22

Before pandemic H1N1 vaccines were available, the potential benefit of existing seasonal trivalent inactivated influenza vaccines (IIV3s) against influenza due to the 2009 pandemic H1N1 influenza strain was investigated, with conflicting results. This study assessed the efficacy of seasonal IIV3s against influenza due to 2008 and 2009 seasonal influenza strains and against the 2009 pandemic H1N1 strain. This observer-blind, randomized, placebo-controlled study enrolled adults aged 18-64years during 2008 and 2009 in Australia and New Zealand. Participants were randomized 2:1 to receive IIV3 or placebo. The primary objective was to demonstrate the efficacy of IIV3 against laboratory-confirmed influenza. Participants reporting an influenza-like illness during the period from 14days after vaccination until 30 November of each study year were tested for influenza by real-time reverse transcription polymerase chain reaction. Over a study period of 2years, 15,044 participants were enrolled (mean age±standard deviation: 35.5±14.7years; 54.4% female). Vaccine efficacy of the 2008 and 2009 IIV3s against influenza due to any strain was 42% (95% confidence interval [CI]: 30%, 52%), whereas vaccine efficacy against influenza due to the vaccine-matched strains was 60% (95% CI: 44%, 72%). Vaccine efficacy of the 2009 IIV3 against influenza due to the 2009 pandemic H1N1 strain was 38% (95% CI: 19%, 53%). No vaccine-related deaths or serious adverse events were reported. Solicited local and systemic adverse events were more frequent in IIV3 recipients than placebo recipients (local: IIV3 74.6% vs placebo 20.4%, p<0.001; systemic: IIV3 46.6% vs placebo 39.1%, p<0.001). The 2008 and 2009 IIV3s were efficacious against influenza due to seasonal influenza strains and the 2009 IIV3 demonstrated moderate efficacy against influenza due to the 2009 pandemic H1N1 strain. Funded by CSL Limited, ClinicalTrials.gov identifier NCT00562484. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Biodegradation of used engine oil by novel strains of Ochrobactrum anthropi HM-1 and Citrobacter freundii HM-2 isolated from oil-contaminated soil.

PubMed

Ibrahim, Haytham M M

2016-12-01

Used engine oil (UEO) constitutes a serious environmental problem due to the difficulty of disposal off or reuse. Ten bacterial strains with biodegradation potential were isolated from UEO-contaminated soil sample using enrichment technique. Two strains which exhibited the highest degradation %, 51 ± 1.2 and 48 ± 1.5, respectively, were selected. Based on the morphological, biochemical characteristics and 16S rRNA sequence analysis, they were identified as Ochrobactrum anthropi HM-1 (accession no: KR360745) and Citrobacter freundii HM-2 (accession no: KR360746). The different conditions which may influence their biodegradation activity, including UEO concentration (1-6 %, v/v), inoculum size (0.5-4 %, v/v), initial pH (6-8), incubation temperature (25-45 °C), and rotation speed (0-200 rpm), were evaluated. The optimum conditions were found to be 2 % UEO, 2 % inoculum size, pH 7.5, incubation temperature 37 °C, and 150 rpm. Under the optimized conditions, strains HM-1, HM-2, and their mixture efficiently degraded UEO, they achieved 65 ± 2.2, 58 ± 2.1, and 80 ± 1.9 %, respectively, after 21 days of incubation. Biodegradation of UEO was confirmed by employing gas chromatography analysis. Gamma radiation (1.5 kGy) enhanced the degradation efficiency of irradiated bacterial mixture (95 ± 2.1 %) as compared to non-irradiated (79 ± 1.6 %). Therefore, strains HM-1 and HM-2 can be employed to develop a cost-effective method for bioremediation of used engine-oil-polluted soil.

Functional Characterization of Probiotic Potential of Novel Pigmented Bacterial Strains for Aquaculture Applications.

PubMed

Jinendiran, Sekar; Boopathi, Seenivasan; Sivakumar, Natesan; Selvakumar, Gopal

2017-11-27

The bioprospecting proficient of novel pigmented probiotic strains with respect to aquaculture industry was unexplored hitherto. In this study, we investigated the probiotic potential of novel pigmented bacterial strains isolated from the indigenous soil sediments in their vicinal habitats, which were screened for their antimicrobial activity against aquatic pathogens using agar well diffusion assay. The strains namely Exiguobacterium acetylicum (S01), Aeromonas veronii (V03), and Chryseobacterium joostei (V04) were phenotypically identified and confirmed by 16S rRNA gene sequence analysis. Further characterization revealed that strains S01 and V03 survive relatively in lower pH and higher bile salt concentrations and possess good adherence ability and broad-spectrum antibiotic susceptibility. The isolate S01 exhibited the higher adhesion ability to hydrocarbons (82%) and mannose-specific adhesion (msa) gene expression. Additionally, the probiotic effects were evaluated in Artemia nauplii fed with algae supplemented with S01, V03, and V04 strains (2.7 × 10 7  cfu/mL) for 3 days under axenic environment. We observed a significant increase (p < 0.05) in the survival rate of Artemia nauplii treated with S01 (83 ± 5%) and V03 (55 ± 5%), whereas the survival rate was only 30 ± 0% in the untreated group. Moreover, the individual length (IL) was increased in treated group S01 (156.7 ± 2.2 μm), V03 (146.1 ± 3.4 μm), and V04 (134.4 ± 2.5 μm) compared with untreated group (116.0 ± 4.8 μm). Our results revealed that E. acetylicum S01 exhibits desirable functional probiotic attributes compared to A. veronii and C. joostei and it would be a promising probiotic strain, which can be efficiently used in the aquaculture applications.

Cariogenicity of a lactate dehydrogenase-deficient mutant of Streptococcus mutans serotype c in gnotobiotic rats.

PubMed

Fitzgerald, R J; Adams, B O; Sandham, H J; Abhyankar, S

1989-03-01

A lactate dehydrogenase-deficient (Ldh-) mutant of a human isolate of Streptococcus mutans serotype c was tested in a gnotobiotic rat caries model. Compared with the wild-type Ldh-positive (Ldh+) strains, it was significantly (alpha less than or equal to 0.005) less cariogenic in experiments with two different sublines of Sprague-Dawley rats. The Ldh- mutant strain 044 colonized the oral cavity of the test animals to the same extent as its parent strain 041, although its initial implantation was slightly but not significantly (P greater than or equal to 0.2) less. Multiple oral or fecal samples plated on 2,3,5-triphenyltetrazolium indicator medium revealed no evidence of back mutation from Ldh- to Ldh+ in vivo. Both Ldh+ strain 041 and Ldh- strain 044 demonstrated bacteriocinlike activity in vitro against a number of human strains of mutans streptococci representing serotype a (S. cricetus) and serotypes c and e (S. mutans). Serotypes b (S. rattus) and f (S. mutans) and strains of S. mitior, S. sanguis, and S. salivarius were not inhibited. Thus, Ldh mutant strain 044 possesses a number of desirable traits that suggest it should be investigated further as a possible effector strain for replacement therapy of dental caries. These traits include its stability and low cariogenicity in the sensitive gnotobiotic rat caries model, its bacteriocinlike activity against certain other cariogenic S. mutans (but not against more inocuous indigenous oral streptococci), and the fact that it is a member of the most prevalent human serotype of cariogenic streptococci.

Differential compartmentalization of Streptococcus pyogenes virulence factors and host protein binding properties as a mechanism for host adaptation.

PubMed

Kilsgård, Ola; Karlsson, Christofer; Malmström, Erik; Malmström, Johan

2016-11-01

Streptococcus pyogenes is an important human pathogen responsible for substantial morbidity and mortality worldwide. Although S. pyogenes is a strictly human pathogen with no other known animal reservoir, several murine infection models exist to explore different aspects of the bacterial pathogenesis. Inoculating mice with wild-type S. pyogenes strains can result in the generation of new bacterial phenotypes that are hypervirulent compared to the original inoculum. In this study, we used a serial mass spectrometry based proteomics strategy to investigate if these hypervirulent strains have an altered distribution of virulence proteins across the intracellular, surface associated and secreted bacterial compartments and if any change in compartmentalization can alter the protein-protein interaction network between bacteria and host proteins. Quantitative analysis of the S. pyogenes surface and secreted proteomes revealed that animal passaged strains are associated with significantly higher amount of virulence factors on the bacterial surface and in the media. This altered virulence factor compartmentalization results in increased binding of several mouse plasma proteins to the bacterial surface, a trend that was consistent for mouse plasma from several different mouse strains. In general, both the wild-type strain and animal passaged strain were capable of binding high amounts of human plasma proteins. However, compared to the non-passaged strains, the animal passaged strains displayed an increased ability to bind mouse plasma proteins, in particular for M protein binders, indicating that the increased affinity for mouse blood plasma proteins is a consequence of host adaptation of this pathogen to a new host. In conclusion, plotting the total amount of virulence factors against the total amount of plasma proteins associated to the bacterial surface could clearly separate out animal passaged strains from wild type strains indicating a virulence model that could predict the virulence of a S. pyogenes strain in mice and which could be used to identify key aspects of this bacteria's pathogenesis. Copyright © 2016 Elsevier GmbH. All rights reserved.

Cold growth behaviour and genetic comparison of Canadian and Swiss Listeria monocytogenes strains associated with the food supply chain and human listeriosis cases.

PubMed

Arguedas-Villa, Carolina; Kovacevic, Jovana; Allen, Kevin J; Stephan, Roger; Tasara, Taurai

2014-06-01

Sixty-two strains of Listeria monocytogenes isolated in Canada and Switzerland were investigated. Comparison based on molecular genotypes confirmed that strains in these two countries are genetically diverse. Interestingly strains from both countries displayed similar range of cold growth phenotypic profiles. Based on cold growth lag phase duration periods displayed in BHI at 4 °C, the strains were similarly divided into groups of fast, intermediate and slow cold adaptors. Overall Swiss strains had faster exponential cold growth rates compared to Canadian strains. However gene expression analysis revealed no significant differences between fast and slow cold adapting strains in the ability to induce nine cold adaptation genes (lmo0501, cspA, cspD, gbuA, lmo0688, pgpH, sigB, sigH and sigL) in response to cold stress exposure. Neither was the presence of Stress survival islet 1 (SSI-1) analysed by PCR associated with enhanced cold adaptation. Phylogeny based on the sigL gene subdivided strains from these two countries into two major and one minor cluster. Fast cold adaptors were more frequently in one of the major clusters (cluster A), whereas slow cold adaptors were mainly in the other (cluster B). Genetic differences between these two major clusters are associated with various amino acid substitutions in the predicted SigL proteins. Compared to the EGDe type strain and most slow cold adaptors, most fast cold adaptors exhibited five identical amino acid substitutions (M90L, S203A/S203T, S304N, S315N, and I383T) in their SigL proteins. We hypothesize that these amino acid changes might be associated with SigL protein structural and functional changes that may promote differences in cold growth behaviour between L. monocytogenes strains. Copyright © 2014 Elsevier Ltd. All rights reserved.

Micropropagation and maintenance of phytoplasmas in tissue culture.

PubMed

Bertaccini, Assunta; Paltrinieri, Samanta; Martini, Marta; Tedeschi, Mara; Contaldo, Nicoletta

2013-01-01

Maintenance of phytoplasma strains in tissue culture is achievable for all strains transmitted to periwinkle (Catharanthus roseus), and also for other naturally infected plant host species. Shoots of 1-3 cm length are grown in a solid medium containing Murashige and Skoog (MS) micro- and macroelements and 0.12 mg/L benzylaminopurine. The continued presence of phytoplasmas in infected shoots of periwinkle that have been maintained in micropropagation for up to 20 years can be shown by diagnostic methods such as nested PCR tests using the 16S rDNA gene (see Chapters 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,and 26 for phytoplasma diagnostic methods).

[Estimation of species diversity of coagulase-negative staphylococci isolated in hospitals of Russian Federation in 2009-2010].

PubMed

Voronina, O L; Kunda, M S; Dmitrienko, O A; Liubasovskaia, L A; Kovalishena, O V; Popov, D A; Lunin, V G

2011-01-01

Comparative analysis of species diversity of sample of coagulase-negative staphylococci (CNS) isolated in hospitals of different specializations. For identification of 102 CNS strains, biochemical systems manufactured by NPO "Diagnostic Systems", VITEK 2 Compact, and BBL Crystal as well as sequencing of fragments of tuf and gap genes were used. Greater differentiating capability of genotyping compared with phenotyping methods for species identification of staphylococci was demonstrated. Six CNS species were identified in the sample: S. epidermidis, S. haemolyticus, S. hominis, S. warneri, S. capitis, and S. pasteuri. The largest species diversity was noted for strains from maternity hospitals in Nizhny Novgorod and Kulakov Scientific Center for Obstetrics, Gynecology and Perinatology. Strains isolated from blood of patients in Bakulev Center for Cardiovascular Surgery were represented mostly by S. epidermidis and S. haemolyticus. Differences in species diversity of CNS--causative agents of neonatal conjunctivitis and omphalitis--were observed. Two species of CNS: S. epidermidis and S. haemolyticus pose special threat as nosocomial pathogens both in hospitals for adults and obstetrical facilities. Additionally, in neonatal units it is necessary to control such species as S. warneri, S. capitis, S. pasteuri.

A multiplex real-time PCR assay, based on invA and pagC genes, for the detection and quantification of Salmonella enterica from cattle lymph nodes.

PubMed

Bai, Jianfa; Trinetta, Valentina; Shi, Xiaorong; Noll, Lance W; Magossi, Gabriela; Zheng, Wanglong; Porter, Elizabeth P; Cernicchiaro, Natalia; Renter, David G; Nagaraja, Tiruvoor G

2018-05-01

Cattle lymph nodes can harbor Salmonella and potentially contaminate beef products. We have developed and validated a new real-time PCR (qPCR) assay for the detection and quantification of Salmonella enterica in cattle lymph nodes. The assay targets both the invA and pagC genes, the most conserved molecular targets in Salmonella enterica. An 18S rRNA gene assay that amplifies from cattle and other animal species was also included as an internal control. Available DNA sequences for invA, pagC and 18S rRNA genes were used for primer and probe selections. Three Salmonella serotypes, S. Typhimurium, S. Anatum, and S. Montevideo, were used to assess the assay's analytical sensitivity. Correlation coefficients of standard curves generated for each target and for all three serotypes were >99% and qPCR amplification efficiencies were between 93% and 110%. Assay sensitivity was also determined using standard curve data generated from Salmonella-negative cattle lymph nodes spiked with 10-fold dilutions of the three Salmonella serotypes. Assay specificity was determined using Salmonella culture method, and qPCR testing on 36 Salmonella strains representing 33 serotypes, 38 Salmonella strains of unknown serotypes, 252 E. coli strains representing 40 serogroups, and 31 other bacterial strains representing 18 different species. A collection of 647 cattle lymph node samples from steers procured from the Midwest region of the US were tested by the qPCR, and compared to culture-method of detection. Salmonella prevalence by qPCR for pre-enriched and enriched lymph nodes was 19.8% (128/647) and 94.9% (614/647), respectively. A majority of qPCR positive pre-enriched samples (105/128) were at concentrations between 10 4 and 10 5  CFU/mL. Culture method detected Salmonella in 7.7% (50/647) and 80.7% (522/647) of pre- and post-enriched samples, respectively; 96.0% (48/50) of pre-enriched and 99.4% (519/522) of post-enriched culture-positive samples were also positive by qPCR. More samples tested positive by qPCR than by culture method, indicating that the real-time PCR assay was more sensitive. Our data indicate that this triplex qPCR can be used to accurately detect and quantify Salmonella enterica strains from cattle lymph node samples. The assay may serve as a useful tool to monitor the prevalence of Salmonella in beef production systems. Copyright © 2018 Elsevier B.V. All rights reserved.

Synthesis of silver nanoparticles from two acidophilic strains of Pilimelia columellifera subsp. pallida and their antibacterial activities.

PubMed

Golińska, Patrycja; Wypij, Magdalena; Rathod, Dnyaneshwar; Tikar, Sagar; Dahm, Hanna; Rai, Mahendra

2016-05-01

Biosynthesis of silver nanoparticles (AgNPs) is an eco-friendly approach by using different biological sources; for example, plants and microorganisms such as bacteria, fungi, and actinobacteria. In this report, we present the biological synthesis of silver nanoparticles (AgNPs) by acidophilic actinomycetes SL19 and SL24 strains isolated from pine forest soil (pH < 4.0). The isolates based on 16S rRNA gene sequence were identified as Pilimelia columellifera subsp. pallida. The synthesized AgNPs were characterized by visual observations of colour change from light-yellow to dark-brown. The UV-vis spectra of AgNPs were recorded at 425 and 430 nm. The AgNPs were further characterized by Nanoparticle tracking analysis (NTA), Zeta potential, Fourier transform infrared spectroscopy (FTIR) and Transmission electron microscopy (TEM). FTIR analysis revealed the presence of proteins as a capping agent. TEM analysis confirmed the formation of spherical and polydispersed NPs of 12.7 and 15.9 nm sizes. The in vitro antibacterial activity of AgNPs alone and in combination with antibiotics was evaluated against clinical bacteria viz., Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and uropathogens such as Enterobacter, S. aureus, P. aeruginosa, K. pneumoniae, and E. coli. The lowest MIC (40 μg ml(-1) ) was demonstrated by AgNPs synthesized from SL24 against E. coli. However, the AgNPs of SL19 showed lowest MIC (70 μg ml(-1) ) against S. aureus. The activity of antibiotic was enhanced, when tested in combination with silver nanoparticles synthesized from both actinobacterial strains. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of Cu addition on the martensitic transformation of powder metallurgy processed Ti–Ni alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Yeon-wook, E-mail: ywk@gw.kmu.ac.kr; Choi, Eunsoo

2014-10-15

Highlights: • M{sub s} of Ti{sub 50}Ni{sub 50} powders is 22 °C, while M{sub s} of SPS-sintered porous bulk increases up to 50 °C. • M{sub s} of Ti{sub 50}Ni{sub 40}Cu{sub 20} porous bulk is only 2 °C higher than that of the powders. • Recovered stain of porous TiNi and TiNiCu alloy is more than 1.5%. - Abstract: Ti{sub 50}Ni{sub 50} and Ti{sub 50}Ni{sub 30}Cu{sub 20} powders were prepared by gas atomization and their transformation behaviors were examined by means of differential scanning calorimetry and X-ray diffraction. One-step B2–B19’ transformation occurred in Ti{sub 50}Ni{sub 50} powders, while Ti{sub 50}Ni{submore » 30}Cu{sub 20} powders showed B2–B19 transformation behavior. Porous bulks with 24% porosity were fabricated by spark plasma sintering. The martensitic transformation start temperature (50 °C) of Ti{sub 50}Ni{sub 50} porous bulk is much higher than that (22 °C) of the as-solidified powders. However, the martensitic transformation start temperature (35 °C) of Ti{sub 50}Ni{sub 30}Cu{sub 20} porous bulk is almost the same as that (33 °C) of the powders. When the specimens were compressed to the strain of 8% and then unloaded, the residual strains of Ti{sub 50}Ni{sub 50} and Ti{sub 50}Ni{sub 30}Cu{sub 20} alloy bulks were 3.95 and 3.7%, respectively. However, these residual strains were recovered up to 1.7% after heating by the shape memory phenomenon.« less

Lactobacillus cerevisiae sp. nov., isolated from a spoiled brewery sample.

PubMed

Koob, Jennifer; Jacob, Fritz; Wenning, Mareike; Hutzler, Mathias

2017-09-01

A Gram-stain-positive, non-motile, rod-shaped bacterium, designated TUM BP 140423000-2250T (=DSM 100836T=LMG 29073T), was isolated from spoiled beer. This bacterium did not form spores, and was catalase-negative and facultatively anaerobic. Its taxonomic position was determined in a polyphasic study. The 16S rRNA gene sequence similarity data showed that the strain belonged to the Lactobacillus genus with the nearest neighbours being Lactobacillus koreensis DCY50T (sequence similarity 99.5 %), Lactobacillus yonginensis THK-V8T (99.2 %) and Lactobacillus parabrevis LMG 11984T (98.7 %). Sequence comparisons of additional phylogenetic markers, pheS and rpoA, confirmed the 16S rRNA gene sequence tree topology. The maximum rpoA sequence similarity was 92.3 % with L. yonginensis THK-V8T. The DNA G+C content of the isolate was 50.0 mol%. The DNA-DNA relatedness showed that strain TUM BP 140423000-2250T could be clearly distinguished from L. koreensis DCY 50T (30.8±0.4 %) and L. yonginensis THK-V8T (23.6±5.9 %). The major fatty acids were C18 : 1ω9c, summed feature 7 (comprised of C19 : 0 cyclo ω10c/C19 : 1ω6c) and C16 : 0. Based on phenotypic and genotypic studies, the authors propose classifying the new isolate as a representative of a novel species of the genus Lactobacillus, Lactobacillus cerevisiae sp. nov. The type strain is deposited at the Research Centre Weihenstephan for Brewing and Food Quality as TUM BP 140423000-2250T (=DSM 100836T=LMG 29073T).

Inhibition of Biofilm Formation by Esomeprazole in Pseudomonas aeruginosa and Staphylococcus aureus

PubMed Central

Singh, Vandana; Arora, Vaneet; Alam, M. Jahangir

2012-01-01

Staphylococcus aureus and Pseudomonas aeruginosa are common nosocomial pathogens responsible for biofilm-associated infections. Proton pump inhibitors (PPI), such as esomeprazole, may have novel antimicrobial properties. The objective of this study was to assess whether esomeprazole prevents sessile bacterial growth and biofilm formation and whether it may have synergistic killing effects with standard antibiotics. The antibiofilm activity of esomeprazole at 0.25 mM was tested against two strains each of S. aureus and P. aeruginosa. Bacterial biofilms were prepared using a commercially available 96-peg-plate Calgary biofilm device. Sessile bacterial CFU counts and biomass were assessed during 72 hours of esomeprazole exposure. The killing activities after an additional 24 hours of vancomycin (against S. aureus) and meropenem (against P. aeruginosa) treatment with or without preexposure to esomeprazole were also assessed by CFU and biomass analyses. P. aeruginosa and S. aureus strains exposed to esomeprazole displayed decreased sessile bacterial growth and biomass (P < 0.001, each parameter). After 72 h of exposure, there was a 1-log10 decrease in the CFU/ml of esomeprazole-exposed P. aeruginosa and S. aureus strains compared to controls (P < 0.001). After 72 h of exposure, measured absorbance was 100% greater in P. aeruginosa control strains than in esomeprazole-exposed strains (P < 0.001). Increased killing and decreased biomass were observed for esomeprazole-treated bacteria compared to untreated controls exposed to conventional antibiotics (P < 0.001, each parameter). Reduced biofilm growth after 24 h was visibly apparent by light micrographs for P. aeruginosa and S. aureus isolates exposed to esomeprazole compared to untreated controls. In conclusion, esomeprazole demonstrated an antibiofilm effect against biofilm-producing S. aureus and P. aeruginosa. PMID:22664967

Boosting the growth of the probiotic strain Lactobacillus paracasei ssp. paracasei F19.

PubMed

Brignone, Desideria; Radmann, Pia; Behr, Jürgen; Vogel, Rudi F

2017-08-01

Single so-called booster substances were added to the fermentation medium of the probiotic strain Lactobacillus (L.) paracasei ssp. paracasei F19 to enhance its growth. A wide screening was carried out in microtiter plates and a statistical analysis of the growth parameters was performed. CFU counts were used to correlate the increase in OD 590nm with the increase in viable cell number. Sodium ascorbate, sodium pyruvate, manganese sulfate and cysteine had a remarkable boosting effect on the growth of L. paracasei F19. Three of the boosters increased the growth rate of the strain and led to a higher cell density and biomass yield in laboratory conditions. Cysteine significantly shortened the lag phase, therefore reducing the fermentation times. The boosters were tested on four additional Lactobacillus species and their growth boosting activity was retained. To investigate whether the growth boosters could improve the tolerance of L. paracasei F19 to the adverse condition in the GI tract, additional tests were performed. Sodium ascorbate and sodium pyruvate exerted a certain antioxidant effect, as they improved the tolerance of L. paracasei F19 to H 2 O 2 . Sodium ascorbate enhanced the growth of the strain in low pH.

Differentiation of Shewanella putrefaciens and Shewanella alga on the basis of whole-cell protein profiles, ribotyping, phenotypic characterization, and 16S rRNA gene sequence analysis.

PubMed Central

Vogel, B F; Jørgensen, K; Christensen, H; Olsen, J E; Gram, L

1997-01-01

Seventy-six presumed Shewanella putrefaciens isolates from fish, oil drillings, and clinical specimens, the type strain of Shewanella putrefaciens (ATCC 8071), the type strain of Shewanella alga (IAM 14159), and the type strain of Shewanella hanedai (ATCC 33224) were compared by several typing methods. Numerical analysis of sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell protein and ribotyping patterns showed that the strains were separated into two distinct clusters with 56% +/- 10% and 40% +/- 14% similarity for whole-cell protein profiling and ribotyping, respectively. One cluster consisted of 26 isolates with 52 to 55 mol% G + C and included 15 human isolates, mostly clinical specimens, 8 isolates from marine waters, and the type strain of S. alga. This homogeneous cluster of mesophilic, halotolerant strains was by all analyses identical to the recently defined species S. alga (U. Simidu et al., Int. J. Syst. Bacteriol, 40:331-336, 1990). Fifty-two typically psychrotolerant strains formed the other, more heterogeneous major cluster, with 43 to 47 mol% G + C. The type strain of S. putrefaciens was included in this group. The two groups were confirmed by 16S rRNA gene sequence analysis. It is concluded that the isolates must be considered two different species, S. alga and S. putrefaciens, and that most mesophilic isolates formerly identified as S. putrefaciens belong to S. alga. The ecological role and potential pathogenicity of S. alga can be evaluated only if the organism is correctly identified. PMID:9172338

Phylogenetic Analysis of the Spike (S) Gene of the New Variants of Porcine Epidemic Diarrhoea Virus in Taiwan.

PubMed

Chiou, H-Y; Huang, Y-L; Deng, M-C; Chang, C-Y; Jeng, C-R; Tsai, P-S; Yang, C; Pang, V F; Chang, H-W

2017-02-01

New variants of porcine epidemic diarrhoea virus (PEDV), which emerged in Taiwan in late 2013, have caused a high morbidity and mortality in neonatal piglets. To investigate the molecular characteristics of the spike (S) gene of the emerging Taiwan PEDV strains for a better understanding of the genetic diversity and relationship among the Taiwan new variants and the global PEDVs, full-length S genes of PEDVs from nine 1-7 day-old piglets from three pig farms in the central and southern Taiwan were sequenced and analysed. The result of phylogenetic analysis of the S gene showed that all the Taiwan PEDV strains were closely related to the non-S INDEL strains from US, Canada and China, suggesting a common ancestor for these strains. As compared with the historic PEDVs and CV777-based vaccine strains, the nine Taiwan PEDV variants shared almost the same genetic signatures as the global non-S INDEL strains, including a series of insertions, deletions and mutations in the amino terminal as well as identical mutations in the neutralizing epitopes of the S gene. The high similarity of the S protein among the Taiwan and the globally emerged non-S INDEL PEDV strains suggests that the Taiwan new variants may share similar pathogenesis and immunogenicity as the global outbreak variants. The development of a novel vaccine based on the Taiwan or the global non-S INDEL strains may be contributive to the control of the current global porcine epidemic diarrhoea outbreaks. © 2015 Blackwell Verlag GmbH.

The effect of metal ions on Staphylococcus aureus revealed by biochemical and mass spectrometric analyses.

PubMed

Chudobova, Dagmar; Dostalova, Simona; Ruttkay-Nedecky, Branislav; Guran, Roman; Rodrigo, Miguel Angel Merlos; Tmejova, Katerina; Krizkova, Sona; Zitka, Ondrej; Adam, Vojtech; Kizek, Rene

2015-01-01

In this study, we focused on the effect of heavy metal ions in resistant strains of gram-positive bacteria Staphylococcus aureus using biochemical methods and mass spectrometry. Five nitrate solutions of heavy metals (Ag(+), Cu(2+), Cd(2+), Zn(2+) and Pb(2+)) were used to create S. aureus resistant strains. Biochemical changes of resistant strains in comparison with the non-resistant control strain of S. aureus were observed by microbiological (measuring - growth curves and inhibition zones) and spectrophotometric methods (antioxidant activity and alaninaminotransferase, aspartateaminotransferase, alkaline phosphatase, γ-glutamyltransferase activities). Mass spectrometry was employed for the qualitative analysis of the samples (changes in S. aureus protein composition) and for the identification of the strains database MALDI Biotyper was employed. Alterations, in terms of biochemical properties and protein composition, were observed in resistant strains compared to non-resistant control strain. Our results describe the possible option for the analysis of S. aureus resistant strains and may thus serve as a support for monitoring of changes in genetic information caused by the forming of resistance to heavy metals. Copyright © 2014 Elsevier GmbH. All rights reserved.

Immune response of Staphylococcus aureus strains in a mouse mastitis model is linked to adaptive capacity and genotypic profiles.

PubMed

Pereyra, Elizabet A L; Sacco, Sofía C; Duré, Andrea; Baravalle, Celina; Renna, María S; Andreotti, Carolina S; Monecke, Stefan; Calvinho, Luis F; Dallard, Bibiana E

2017-05-01

Staphylococcus aureus is one of the most frequently isolated major pathogens from intramammary infections (IMI) worldwide. The mechanisms by which S. aureus IMI are established and maintained in dairy cows involve both bacterial escape strategies and modulation of the host immune response. Moreover, it was shown that different S. aureus strains have varying effects on the immune response. The aim of this study was to investigate the immune response in a mouse mastitis model of two S. aureus strains isolated from bovine IMI with different clinical manifestation (persistent-P or non-persistent-NP), phenotypic and genotypic profile. Both strains were capable of establishing an IMI after 264h post inoculation (pi). Strain A (NP) showed a more aggressive behaviour than strain B (P) at early stages of IMI, while strain B multiplied initially at a lower rate but increased its replication capacity from 120h pi to the end of the study (264h pi). Strain A triggered a stronger initial inflammatory response compared with strain B inducing higher gene and protein expression of TLR2, NF-κB activation and higher gene expression of IL-1α at initial stage of IMI (6-12h pi) but inducing extensive mammary tissue damage. Immune cells response was different for each S. aureus strain throughout the course of infection, showing mammary glands inoculated with strain A greater initial immune cells stimulation compared with strain B and then a second immune cells stimulation (from 120 to 264h pi) represented by monocytes-macrophages, T and B lymphocytes, mainly stimulated by strain B, consistent with inflammatory process becoming chronic. Strain-specific pathogenicity observed underscores the importance of pathogen factors in the progression of the infectious process. These results contribute to increase the available information on host-pathogen interaction and point out for the need of further research to expand the knowledge about these interactions for developing new strategies to intervene in the IMI progress. Copyright © 2017 Elsevier B.V. All rights reserved.

Molecular analysis of the rRNA genes of Babesia spp and Ehrlichia canis detected in dogs from RibeirÃo Preto, Brazil

PubMed Central

Oliveira, L.P.; Cardozo, G.P.; Santos, E.V.; Mansur, M.A.B.; Donini, I.A.N.; Zissou, V.G.; Roberto, P.G.; Marins, M.

2009-01-01

The partial DNA sequences of the 18S rRNA gene of Babesia canis and the 16S rRNA gene of Ehrlichia canis detected in dogs from Ribeirão Preto, Brazil, were compared to sequences from other strains deposited in GenBank. The E. canis strain circulating in Ribeirão Preto is identical to other strains previously detected in the region, whereas the subspecies Babesia canis vogeli is the main Babesia strain circulating in dogs from Ribeirão Preto. PMID:24031351

Comparative proteomic analysis of engineered Saccharomyces cerevisiae with enhanced free fatty acid accumulation.

PubMed

Chen, Liwei; Lee, Jaslyn Jie Lin; Zhang, Jianhua; Chen, Wei Ning

2016-02-01

The engineered Saccharomyces cerevisiae strain △faa1△faa4 [Acot5s] was demonstrated to accumulate more free fatty acids (FFA) previously. Here, comparative proteomic analysis was performed to get a global overview of metabolic regulation in the strain. Over 500 proteins were identified, and 82 of those proteins were found to change significantly in the engineered strains. Proteins involved in glycolysis, acetate metabolism, fatty acid synthesis, TCA cycle, glyoxylate cycle, the pentose phosphate pathway, respiration, transportation, and stress response were found to be upregulated in △faa1△faa4 [Acot5s] as compared to the wild type. On the other hand, proteins involved in glycerol, ethanol, ergosterol, and cell wall synthesis were downregulated. Taken together with our metabolite analysis, our results showed that the disruption of Faa1 and Faa4 and expression of Acot5s in the engineered strain △faa1△faa4 [Acot5s] not only relieved the feedback inhibition of fatty acyl-CoAs on fatty acid synthesis, but also caused a major metabolic rearrangement. The rearrangement redirected carbon flux toward the pathways which generate the essential substrates and cofactors for fatty acid synthesis, such as acetyl-CoA, ATP, and NADPH. Therefore, our results help shed light on the mechanism for the increased production of fatty acids in the engineered strains, which is useful in providing information for future studies in biofuel production.

Selected Schizosaccharomyces pombe Strains Have Characteristics That Are Beneficial for Winemaking

PubMed Central

Benito, Ángel; Jeffares, Daniel; Palomero, Felipe; Calderón, Fernando; Bai, Feng-Yan; Bähler, Jürg; Benito, Santiago

2016-01-01

At present, wine is generally produced using Saccharomyces yeast followed by Oenococus bacteria to complete malolactic fermentation. This method has some unsolved problems, such as the management of highly acidic musts and the production of potentially toxic products including biogenic amines and ethyl carbamate. Here we explore the potential of the fission yeast Schizosaccharomyces pombe to solve these problems. We characterise an extensive worldwide collection of S. pombe strains according to classic biochemical parameters of oenological interest. We identify three genetically different S. pombe strains that appear suitable for winemaking. These strains compare favourably to standard Saccharomyces cerevisiae winemaking strains, in that they perform effective malic acid deacidification and significantly reduce levels of biogenic amines and ethyl carbamate precursors without the need for any secondary bacterial malolactic fermentation. These findings indicate that the use of certain S. pombe strains could be advantageous for winemaking in regions where malic acid is problematic, and these strains also show superior performance with respect to food safety. PMID:27007548

The Biosynthesis of Capuramycin-type Antibiotics

PubMed Central

Cai, Wenlong; Goswami, Anwesha; Yang, Zhaoyong; Liu, Xiaodong; Green, Keith D.; Barnard-Britson, Sandra; Baba, Satoshi; Funabashi, Masanori; Nonaka, Koichi; Sunkara, Manjula; Morris, Andrew J.; Spork, Anatol P.; Ducho, Christian; Garneau-Tsodikova, Sylvie; Thorson, Jon S.; Van Lanen, Steven G.

2015-01-01

A-500359s, A-503083s, and A-102395 are capuramycin-type nucleoside antibiotics that were discovered using a screen to identify inhibitors of bacterial translocase I, an essential enzyme in peptidoglycan cell wall biosynthesis. Like the parent capuramycin, A-500359s and A-503083s consist of three structural components: a uridine-5′-carboxamide (CarU), a rare unsaturated hexuronic acid, and an aminocaprolactam, the last of which is substituted by an unusual arylamine-containing polyamide in A-102395. The biosynthetic gene clusters for A-500359s and A-503083s have been reported, and two genes encoding a putative non-heme Fe(II)-dependent α-ketoglutarate:UMP dioxygenase and an l-Thr:uridine-5′-aldehyde transaldolase were uncovered, suggesting that C–C bond formation during assembly of the high carbon (C6) sugar backbone of CarU proceeds from the precursors UMP and l-Thr to form 5′-C-glycyluridine (C7) as a biosynthetic intermediate. Here, isotopic enrichment studies with the producer of A-503083s were used to indeed establish l-Thr as the direct source of the carboxamide of CarU. With this knowledge, the A-102395 gene cluster was subsequently cloned and characterized. A genetic system in the A-102395-producing strain was developed, permitting the inactivation of several genes, including those encoding the dioxygenase (cpr19) and transaldolase (cpr25), which abolished the production of A-102395, thus confirming their role in biosynthesis. Heterologous production of recombinant Cpr19 and CapK, the transaldolase homolog involved in A-503083 biosynthesis, confirmed their expected function. Finally, a phosphotransferase (Cpr17) conferring self-resistance was functionally characterized. The results provide the opportunity to use comparative genomics along with in vivo and in vitro approaches to probe the biosynthetic mechanism of these intriguing structures. PMID:25855790

Salmonella DIVA vaccine reduces disease, colonization and shedding due to virulent S. Typhimurium infection in swine

PubMed Central

Bearson, Shawn M. D; Brunelle, Brian W; Bayles, Darrell O; Lee, In Soo; Kich, Jalusa D

2017-01-01

Purpose Non-host-adapted Salmonella serovars, including the common human food-borne pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium), are opportunistic pathogens that can colonize food-producing animals without causing overt disease. Interventions against Salmonella are needed to enhance food safety, protect animal health and allow the differentiation of infected from vaccinated animals (DIVA). Methodology An attenuated S. Typhimurium DIVA vaccine (BBS 866) was characterized for the protection of pigs following challenge with virulent S. Typhimurium. The porcine transcriptional response to BBS 866 vaccination was evaluated. RNA-Seq analysis was used to compare gene expression between BBS 866 and its parent; phenotypic assays were performed to confirm transcriptional differences observed between the strains. Results Vaccination significantly reduced fever and interferon-gamma (IFNγ) levels in swine challenged with virulent S. Typhimurium compared to mock-vaccinated pigs. Salmonella faecal shedding and gastrointestinal tissue colonization were significantly lower in vaccinated swine. RNA-Seq analysis comparing BBS 866 to its parental S. Typhimurium strain demonstrated reduced expression of the genes involved in cellular invasion and bacterial motility; decreased invasion of porcine-derived IPEC-J2 cells and swimming motility for the vaccine strain was consistent with the RNA-Seq analysis. Numerous membrane proteins were differentially expressed, which was an anticipated gene expression pattern due to the targeted deletion of several regulatory genes in the vaccine strain. RNA-Seq analysis indicated that genes involved in the porcine immune and inflammatory response were differentially regulated at 2 days post-vaccination compared to pre-vaccination. Conclusion Evaluation of the S. Typhimurium DIVA vaccine indicates that vaccination will provide both swine health and food safety benefits. PMID:28516860

Identification of a functional capsule locus in Streptococcus mitis.

PubMed

Rukke, H V; Hegna, I K; Petersen, F C

2012-04-01

The polysaccharide capsule of Streptococcus pneumoniae is a hallmark for virulence in humans. In its close relative Streptococcus mitis, a common human commensal, analysis of the sequenced genomes of six strains revealed the presence of a putative capsule locus in four of them. We constructed an isogenic S. mitis mutant from the type strain that lacked the 19 open reading frames in the capsule locus (Δcps mutant), using a deletion strategy similar to previous capsule functional studies in S. pneumoniae. Transmission electron microscopy and atomic force microscopy revealed a capsule-like structure in the S. mitis type strain that was absent or reduced in the Δcps mutant. Since S. mitis are predominant oral colonizers of tooth surfaces, we addressed the relevance of the capsule locus for the S. mitis overall surface properties, autoaggregation and biofilm formation. The capsule deletion resulted in a mutant with approximately two-fold increase in hydrophobicity. Binding to the Stains-all cationic dye was reduced by 40%, suggesting a reduction in the overall negative surface charge of the mutant. The mutant exhibited also increased autoaggregation in coaggregation buffer, and up to six-fold increase in biofilm levels. The results suggested that the capsule locus is associated with production of a capsule-like structure in S. mitis and indicated that the S. mitis capsule-like structure may confer surface attributes similar to those associated with the capsule in S. pneumoniae. © 2011 John Wiley & Sons A/S.

Trading Capsule for Increased Cytotoxin Production: Contribution to Virulence of a Newly Emerged Clade of emm89 Streptococcus pyogenes.

PubMed

Zhu, Luchang; Olsen, Randall J; Nasser, Waleed; de la Riva Morales, Ivan; Musser, James M

2015-10-06

Strains of emm89 Streptococcus pyogenes have become one of the major causes of invasive infections worldwide in the last 10 years. We recently sequenced the genome of 1,125 emm89 strains and identified three major phylogenetic groups, designated clade 1, clade 2, and the epidemic clade 3. Epidemic clade 3 strains, which now cause the great majority of infections, have two distinct genetic features compared to clade 1 and clade 2 strains. First, all clade 3 organisms have a variant 3 nga promoter region pattern, which is associated with increased production of secreted cytolytic toxins SPN (S. pyogenes NADase) and SLO (streptolysin O). Second, all clade 3 strains lack the hasABC locus mediating hyaluronic acid capsule synthesis, whereas this locus is intact in clade 1 and clade 2 strains. We constructed isogenic mutant strains that produce different levels of SPN and SLO toxins and capsule (none, low, or high). Here we report that emm89 strains with elevated toxin production are significantly more virulent than low-toxin producers. Importantly, we also show that capsule production is dispensable for virulence in strains that already produce high levels of SPN and SLO. Our results provide new understanding about the molecular mechanisms contributing to the rapid emergence and molecular pathogenesis of epidemic clade 3 emm89 S. pyogenes. S. pyogenes (group A streptococcus [GAS]) causes pharyngitis ("strep throat"), necrotizing fasciitis, and other human infections. Serious infections caused by emm89 S. pyogenes strains have recently increased in frequency in many countries. Based on whole-genome sequence analysis of 1,125 strains recovered from patients on two continents, we discovered that a new emm89 clone, termed clade 3, has two distinct genetic features compared to its predecessors: (i) absence of the genes encoding antiphagocytic hyaluronic acid capsule virulence factor and (ii) increased production of the secreted cytolytic toxins SPN and SLO. emm89 S. pyogenes strains with the clade 3 phenotype (absence of capsule and high expression of SPN and SLO) are highly virulent in mice. These findings provide new understanding of how new virulent clones emerge and cause severe infections worldwide. This newfound knowledge of S. pyogenes virulence can be used to help understand future epidemics and conduct new translational research. Copyright © 2015 Zhu et al.

Characterization of Francisella tularensis Schu S4 mutants identified from a transposon library screened for O-antigen and capsule deficiencies

PubMed Central

Rasmussen, Jed A.; Fletcher, Joshua R.; Long, Matthew E.; Allen, Lee-Ann H.; Jones, Bradley D.

2015-01-01

The lipopolysaccharide (LPS) and O-antigen polysaccharide capsule structures of Francisella tularensis play significant roles in helping these highly virulent bacteria avoid detection within a host. We previously created pools of F. tularensis mutants that we screened to identify strains that were not reactive to a monoclonal antibody to the O-antigen capsule. To follow up previously published work, we characterize further seven of the F. tularensis Schu S4 mutant strains identified by our screen. These F. tularensis strains carry the following transposon mutations: FTT0846::Tn5, hemH::Tn5, wbtA::Tn5, wzy::Tn5, FTT0673p/prsA::Tn5, manB::Tn5, or dnaJ::Tn5. Each of these strains displayed sensitivity to human serum, to varying degrees, when compared to wild-type F. tularensis Schu S4. By Western blot, only FTT0846::Tn5, wbtA::Tn5, wzy::Tn5, and manB::Tn5 strains did not react to the capsule and LPS O-antigen antibody 11B7, although the wzy::Tn5 strain did have a single O-antigen reactive band that was detected by the FB11 monoclonal antibody. Of these strains, manB::Tn5 and FTT0846 appear to have LPS core truncations, whereas wbtA::Tn5 and wzy::Tn5 had LPS core structures that are similar to the parent F. tularensis Schu S4. These strains were also shown to have poor growth within human monocyte derived macrophages (MDMs) and bone marrow derived macrophages (BMDMs). We examined the virulence of these strains in mice, following intranasal challenge, and found that each was attenuated compared to wild type Schu S4. Our results provide additional strong evidence that LPS and/or capsule are F. tularensis virulence factors that most likely function by providing a stealth shield that prevents the host immune system from detecting this potent pathogen. PMID:25999917

Pathogenic Escherichia coli strain discrimination using laser-induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Diedrich, Jonathan; Rehse, Steven J.; Palchaudhuri, Sunil

2007-07-01

A pathogenic strain of bacteria, Escherichia coli O157:H7 (enterohemorrhagic E. coli or EHEC), has been analyzed by laser-induced breakdown spectroscopy (LIBS) with nanosecond pulses and compared to three nonpathogenic E. coli strains: a laboratory strain of K-12 (AB), a derivative of the same strain termed HF4714, and an environmental strain, E. coli C (Nino C). A discriminant function analysis (DFA) was performed on the LIBS spectra obtained from live colonies of all four strains. Utilizing the emission intensity of 19 atomic and ionic transitions from trace inorganic elements, the DFA revealed significant differences between EHEC and the Nino C strain, suggesting the possibility of identifying and discriminating the pathogenic strain from commonly occurring environmental strains. EHEC strongly resembled the two K-12 strains, in particular, HF4714, making discrimination between these strains difficult. DFA was also used to analyze spectra from two of the nonpathogenic strains cultured in different media: on a trypticase soy (TS) agar plate and in a liquid TS broth. Strains cultured in different media were identified and effectively discriminated, being more similar than different strains cultured in identical media. All bacteria spectra were completely distinct from spectra obtained from the nutrient medium or ablation substrate alone. The ability to differentiate strains prepared and tested in different environments indicates that matrix effects and background contaminations do not necessarily preclude the use of LIBS to identify bacteria found in a variety of environments or grown under different conditions.

Genotyping of Salmonella enterica serovar Typhi strains isolated from 1959 to 2006 in China and analysis of genetic diversity by genomic microarray.

PubMed

Zhang, Haifang; Zhang, Xiaolei; Yan, Meiying; Pang, Bo; Kan, Biao; Xu, Huaxi; Huang, Xinxiang

2011-12-15

To determine the genotype of Salmonella enterica serovar Typhi (S. Typhi) strains in China and analyze their genetic diversity. We collected S. Typhi strains from 1959 to 2006 in five highly endemic Chinese provinces and chose 40 representative strains. Multilocus sequence typing was used to determine the genotypes or sequence types (ST) and microarray-based comparative genomic hybridization (M-CGH) to investigate the differences in gene content among these strains. Forty representative S. Typhi strains belonged to 4 sequence types (ST1, ST2, ST890, and ST892). The predominant S. Typhi genotype (31/40) was ST2 and it had a diverse geographic distribution. We discovered two novel STs - ST890 and ST892. M-CGH showed that 69 genes in these two novel STs were divergent from S. Typhi Ty2, which belongs to ST1. In addition, 5 representative Typhi strains of ST2 isolated from Guizhou province showed differences in divergent genes. We determined two novel sequence types, ST890 and ST892, and found that ST2 was the most prevalent genotype of S. Typhi in China. Genetic diversity was present even within a highly clonal bacterial population.

When intensity of deltamethrin resistance in Anopheles gambiae s.l. leads to loss of Long Lasting Insecticidal Nets bio-efficacy: a case study in north Cameroon.

PubMed

Etang, Josiane; Pennetier, Cédric; Piameu, Michael; Bouraima, Aziz; Chandre, Fabrice; Awono-Ambene, Parfait; Marc, Coosemans; Corbel, Vincent

2016-03-08

In Cameroon, insecticide resistance in Anopheles (An.) gambiae s.l. has been reported in several foci, prompting further investigations on associated patterns of Long-Lasting Insecticidal Nets (LLINs) bio-efficacy. The current study, conducted from June to August 2011, explored the intensity of deltamethrin resistance in An. gambiae s.l. from Pitoa and its impact on the residual bio-efficacy of LifeNet, a LLIN with deltamethrin incorporated into polypropylene nets (PND). Two-four days old females An. gambiae s.l. reared from larval collections in Pitoa were tested for susceptibility to DDT, permethrin and deltamethrin, using standard World Health Organization (WHO) tube assays. Intensity of deltamethrin resistance was explored using WHO tube assays, but across six working concentrations from 0.001 % to 0.5 %. Bio-efficacy of unwashed and washed PND was assessed using WHO cone test. Species identification and kdr 1014 genotyping were performed on mosquito samples that were not exposed to insecticides, using PCR-RFLP and HOLA methods respectively. The Kisumu reference susceptible strain of An. gambiae s.s. was used for comparisons. A total of 1895 An. gambiae s.l. specimens from Pitoa were used for resistance and PND bio-efficacy testing. This mosquito population was resistant to DDT, permethrin and deltamethrin, with 18-40 min knockdown times for 50 % of tested mosquitoes and 59-77 % mortality. Deltamethrin Resistance Ratio compared with the Kisumu strain was estimated at ≥500 fold. LifeNets were effective against the susceptible Kisumu (100 % knockdown (KD60min) and mortality) and the resistant Pitoa samples (95 % KD60min, 83-95 % mortality). However, the bio-efficacy gradually dropped against the Pitoa samples when nets were washed (X (2) = 35.887, df = 8, p < 0.001), and fell under the WHO efficacy threshold (80 % mortality and/or 95 % KD60min) between 10 and 15 washes. The Pitoa samples were composed of three sibling species: An. arabiensis (132/154, 86 %), An. coluzzii (19/154, 12 %) and An. gambiae s.s. (3/154, 2 %). The kdr L1014F allele was found only in An. coluzzii (Npositive = 13/19), at 34 % frequency and heterozygote stage. No specimen carried the kdr L1014S allele. The current study showed that LifeNet might still offer some protection against the resistant An. gambiae s.l. population from Pitoa, provided appropriate dose of insecticide is available on the nets.

Roseomonas aerofrigidensis sp. nov., isolated from an air conditioner.

PubMed

Hyeon, Jong Woo; Jeon, Che Ok

2017-10-01

A Gram-stain-negative, strictly aerobic bacterium, designated HC1 T , was isolated from an air conditioner in South Korea. Cells were orange, non-motile cocci with oxidase- and catalase-positive activities and did not contain bacteriochlorophyll a. Growth of strain HC1 T was observed at 10-45 °C (optimum, 30 °C), pH 4.5-9.5 (optimum, pH 7.0) and 0-3 % (w/v) NaCl (optimum, 0 %). Strain HC1 T contained summed feature 8 (comprising C18 : 1ω7c/C18 : 1ω6c), C16 : 0 and cyclo-C19 : 0ω8c as the major fatty acids and ubiquinone-10 as the sole isoprenoid quinone. Phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and an unknown aminolipid were detected as the major polar lipids. The major carotenoid was hydroxyspirilloxanthin. The G+C content of the genomic DNA was 70.1 mol%. Phylogenetic analysis, based on 16S rRNA gene sequences, showed that strain HC1 T formed a phylogenetic lineage within the genus Roseomonas. Strain HC1 T was most closely related to the type strains of Roseomonas oryzae, Roseomonas rubra, Roseomonas aestuarii and Roseomonas rhizosphaerae with 98.1, 97.9, 97.6 and 96.8 % 16S rRNA gene sequence similarities, respectively, but the DNA-DNA relatedness values between strain HC1 T and closely related type strains were less than 70 %. Based on phenotypic, chemotaxonomic and molecular properties, strain HC1 T represents a novel species of the genus Roseomonas, for which the name Roseomonas aerofrigidensis sp. nov. is proposed. The type strain is HC1 T (=KACC 19097 T =JCM 31878 T ).

Gordonia caeni sp. nov., isolated from sludge of a sewage disposal plant.

PubMed

Srinivasan, Sathiyaraj; Park, Giho; Yang, Hyejin; Hwang, Supyong; Bae, Yoonjung; Jung, Yong-An; Kim, Myung Kyum; Lee, Myungjin

2012-11-01

A Gram-stain-positive, strictly aerobic, short-rod-shaped, non-motile strain (designated MJ32(T)) was isolated from a sludge sample of the Daejeon sewage disposal plant in South Korea. A polyphasic approach was applied to study the taxonomic position of strain MJ32(T). Strain MJ32(T) showed highest 16S rRNA gene sequence similarity to Gordonia hirsuta DSM 44140(T) (98.1%) and Gordonia hydrophobica DSM 44015(T) (97.0%); levels of sequence similarity to the type strains of other recognized Gordonia species were less than 97.0%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain MJ32(T) belonged to the clade formed by members of the genus Gordonia in the family Gordoniaceae. The G+C content of the genomic DNA of strain MJ32(T) was 69.2 mol%. Chemotaxonomically, strain MJ32(T) showed features typical of the genus Gordonia. The predominant respiratory quinone was MK-9(H(2)), the mycolic acids present had C(56)-C(60) carbon atoms, and the major fatty acids were C(16:0) (34.6%), tuberculostearic acid (21.8%), C(16:1)ω7c (19.5%) and C(18:1)ω9c (12.7%). The peptidoglycan type was based on meso-2,6-diaminopimelic acid as the diagnostic diamino acid with glycolated sugars. On the basis of phylogenetic inference, fatty acid profile and other phenotypic properties, strain MJ32(T) is considered to represent a novel species of the genus Gordonia, for which the name Gordonia caeni sp. nov. is proposed. The type strain is MJ32(T) (=KCTC 19771(T)=JCM 16923(T)).

Construction of two novel reciprocal conplastic rat strains and characterization of cardiac mitochondria

PubMed Central

Kumarasamy, Sivarajan; Gopalakrishnan, Kathirvel; Abdul-Majeed, Shakila; Partow-Navid, Rod; Farms, Phyllis

2013-01-01

Because of the lack of appropriate animal models, the potentially causal contributions of inherited mitochondrial genomic factors to complex traits are less well studied compared with inherited nuclear genomic factors. We previously detected variations between the mitochondrial DNA (mtDNA) of the Dahl salt-sensitive (S) rat and the spontaneously hypertensive rat (SHR). Specifically, multiple variations were detected in mitochondrial genes coding for subunits of proteins essential for electron transport, in mitochondrial reactive oxygen species production, and within the D-loop region. To evaluate the effects of these mtDNA variations in the absence of the corresponding nuclear genomic factors as confounding variables, novel reciprocal strains of S and SHR were constructed and characterized. When compared with that of the S rat, the heart tissue from the S.SHRmt conplastic strain wherein the mtDNA of the S rat was substituted with that of the SHR had a significant increase in mtDNA copy number and decrease in mitochondrial reactive oxygen species production. A corresponding increase in aerobic treadmill running capacity and a significant increase in survival that was not related to changes in blood pressure were observed in the S.SHRmt rats compared with the S rat. The reciprocal SHR.Smt rats did not differ from the SHR in any phenotype tested, suggesting lower penetrance of the S mtDNA on the nuclear genomic background of the SHR. These novel conplastic strains serve as invaluable tools to further dissect the relationship between heart function, aerobic fitness, cardiovascular disease progression, and mortality. PMID:23125210

Comparative in vitro activity of the new oxacephem antibiotic, flomoxef (6315-S).

PubMed

Ruckdeschel, G; Eder, W

1988-10-01

The in vitro activity of flomoxef (6315-S) was determined and compared to that of different cephalosporins against 787 clinical isolates of staphylococci, Enterobacteriaceae and anaerobes. Flomoxef is similar in activity to latamoxef and cefotaxime against Enterobacteriaceae, slightly more active than cephalothin and cefamandole against oxacillin-sensitive strains of Staphylococcus aureus and minimally less active than cefamandole against oxacillin-resistant strains. Flomoxef showed similar or better activity than latamoxef and cefoxitin against most of the anaerobic species of medical importance.

Al2O3 Nanoparticle Addition to Commercial Magnesium Alloys: Multiple Beneficial Effects

PubMed Central

Paramsothy, Muralidharan; Chan, Jimmy; Kwok, Richard; Gupta, Manoj

2012-01-01

The multiple beneficial effects of Al2O3 nanoparticle addition to cast magnesium based systems (followed by extrusion) were investigated, constituting either: (a) enhanced strength; or (b) simultaneously enhanced strength and ductility of the corresponding magnesium alloys. AZ31 and ZK60A nanocomposites containing Al2O3 nanoparticle reinforcement were each fabricated using solidification processing followed by hot extrusion. Compared to monolithic AZ31 (tension levels), the corresponding nanocomposite exhibited higher yield strength (0.2% tensile yield strength (TYS)), ultimate strength (UTS), failure strain and work of fracture (WOF) (+19%, +21%, +113% and +162%, respectively). Compared to monolithic AZ31 (compression levels), the corresponding nanocomposite exhibited higher yield strength (0.2% compressive yield strength (CYS)) and ultimate strength (UCS), lower failure strain and higher WOF (+5%, +5%, −4% and +11%, respectively). Compared to monolithic ZK60A (tension levels), the corresponding nanocomposite exhibited lower 0.2% TYS and higher UTS, failure strain and WOF (−4%, +13%, +170% and +200%, respectively). Compared to monolithic ZK60A (compression levels), the corresponding nanocomposite exhibited lower 0.2% CYS and higher UCS, failure strain and WOF (−10%, +7%, +15% and +26%, respectively). The capability of Al2O3 nanoparticles to enhance the properties of cast magnesium alloys in a way never seen before with micron length scale reinforcements is clearly demonstrated. PMID:28348301

Albibacter methylovorans gen. nov., sp. nov., a novel aerobic, facultatively autotrophic and methylotrophic bacterium that utilizes dichloromethane.

PubMed

Doronina, N V; Trotsenko, Y A; Tourova, T P; Kuznetsov, B B; Leisinger, T

2001-05-01

A novel genus, Albibacter, with one species, Albibacter methylovorans sp. nov., is proposed for a facultatively chemolithotrophic and methylotrophic bacterium (strain DM10T) with the ribulose bisphosphate (RuBP) pathway of C1 assimilation. The bacterium is a Gram-negative, aerobic, asporogenous, nonmotile, colourless rod that multiplies by binary fission. The organism utilizes dichloromethane, methanol, methylamine, formate and CO2/H2, as well as a variety of polycarbon compounds, as carbon and energy sources. It is neutrophilic and mesophilic. The major cellular fatty acids are straight-chain unsaturated C18:1, saturated C16:0 and cyclopropane C19:0 acids. The main ubiquinone is Q-10. The dominant phospholipids are phosphatidyl ethanolamine, phosphatidyl glycerol, phosphatidyl choline and cardiolipin. The DNA G+C content is 66.7 mol%. Strain DM10T has a very low degree of DNA-DNA hybridization (4-7%) with the type species of the genera Paracoccus, Xanthobacter, Blastobacter, Angulomicrobium, Ancylobacter and Ralstonia of RuBP pathway methylobacteria. Another approach, involving comparative 16S rDNA analysis, has shown that the novel isolate represents a separate branch within the alpha-2 subgroup of the Proteobacteria. The type species of the new genus is Albibacter methylovorans sp. nov.; the type strain is DM10T (= VKM B-2236T = DSM 13819T).

Comparison of aerially-applied Gypchek strains against gypsy moth (Lepidoptera: Lymantriidae) in the presence of an Entomophaga maimaiga epizootic

Treesearch

R.E. Webb; G.B. White; J.D. Podgwaite; V. D' Amico; J. Slavicek; J. Swearingen; B. Onken; K.W. Thorpe

2005-01-01

The standard strain (LDP-226) of Gypchek®, a nucleopolyhedrovirus product registered by the USDA Forest Service against the gypsy moth, Lymantria dispar (L.), was compared against a strain, LdMNPV-203NL (NL = nonliquefying), that was developed for production in cell culture. Both strains were applied by air to U.S. government property in...

Transcriptomic and metabolic responses of Staphylococcus aureus in mixed culture with Lactobacillus plantarum, Streptococcus thermophilus and Enterococcus durans in milk.

PubMed

Zdenkova, Kamila; Alibayov, Babek; Karamonova, Ludmila; Purkrtova, Sabina; Karpiskova, Renata; Demnerova, Katerina

2016-09-01

Staphylococcus aureus is a major food-borne pathogen due to the production of enterotoxin and is particularly prevalent in contaminated milk and dairy products. The lactic acid bacteria (LAB) are widely used as biocontrol agents in fermented foods which can inhibit pathogenic flora. In our work, we investigated the influence of three strains of LAB (Lactobacillus plantarum, Streptococcus thermophilus and Enterococcus durans) on the relative expression of three enterotoxin genes (sea, sec, sell) and eight virulence and/or regulatory genes (sarA, saeS, codY, srrA, rot, hld/RNAIII, agrA/RNAII, sigB) in two S. aureus strains (MW2 and Sa1612) in TSB and reduced-fat milk (1.5 %) at 30 °C over a 24-h period. The tested LAB and S. aureus strains proved to be mutually non-competitive or only slightly competitive during co-cultivation. In addition, under the above-mentioned conditions, differential gene expression between the S. aureus MW2 and Sa1612 strains was well documented. S. aureus growth was changed in mixed culture with LAB; however, its effect on the repression of sea and sec expression correlated with production of these virulence factors. In comparison, the presence of LAB strains generally inhibited the expression of sec, sell, sarA, seaS, agrA/RNAII and hld/RNAIII genes. The effect of LAB strains presence on the expression of sea, codY, srrA, rot and sigB genes was medium, time, LAB and S. aureus strain specific. SEA and SEC production was significantly reduced in milk compared to TSB in pure culture. After the 24-h cultivation, S. aureus MW2 and Sa1612 SEC production was 187 and 331 times lower in milk compared to TSB, respectively (0.07 and 0.39 ng/mL in milk, versus 13.1 and 129.2 ng/mL in TSB, respectively). At the same time S. aureus MW2 and Sa1612 SEA production was 77 and 68 times lower in milk compared to TSB, respectively (0.99 and 0.17 ng/mL in milk, versus 76.4 and 11.5 ng/mL in TSB, respectively). This study has revealed new insights into the interaction between S. aureus and LAB (L. plantarum, S. thermophilus, E. durans) on the level of the expression and/or production of S. aureus enterotoxins, regulatory and virulence genes in different media, including milk. This study provides data which may improve the quality of food production.

Haploid deletion strains of Saccharomyces cerevisiae that determine survival during space flight

NASA Astrophysics Data System (ADS)

Johanson, Kelly; Allen, Patricia L.; Gonzalez-Villalobos, Romer A.; Nesbit, Jacqueline; Nickerson, Cheryl A.; Höner zu Bentrup, Kerstin; Wilson, James W.; Ramamurthy, Rajee; D'Elia, Riccardo; Muse, Kenneth E.; Hammond, Jeffrey; Freeman, Jake; Stodieck, Louis S.; Hammond, Timothy G.

2007-02-01

This study identifies genes that determine survival during a space flight, using the model eukaryotic organism, Saccharomyces cerevisiae. Select strains of a haploid yeast deletion series grew during storage in distilled water in space, but not in ground based static or clinorotation controls. The survival advantages in space in distilled water include a 133-fold advantage for the deletion of PEX19, a chaperone and import receptor for newly- synthesized class I peroxisomal membrane proteins, to 77-40 fold for deletion strains lacking elements of aerobic respiration, isocitrate metabolism, and mitochondrial electron transport. Following automated addition of rich growth media, the space flight was associated with a marked survival advantage of strains with deletions in catalytically active genes including hydrolases, oxidoreductases and transferases. When compared to static controls, space flight was associated with a marked survival disadvantage of deletion strains lacking transporter, antioxidant and catalytic activity. This study identifies yeast deletion strains with a survival advantage during storage in distilled water and space flight, and amplifies our understanding of the genes critical for survival in space.

The distribution of extracellular cellulase activity in marine Eukaryotes, thraustochytrids.

PubMed

Nagano, Naoki; Matsui, Shou; Kuramura, Tomoyo; Taoka, Yousuke; Honda, Daiske; Hayashi, Masahiro

2011-04-01

Cellulolytic ability was evaluated in 19 strains of thraustochytrids, representing nine genera, using carboxymethylcellulose (CMC) as a substrate. Extracellular cellulolytic enzyme activity was determined in the culture supernatants during cell growth. CMC hydrolysis was observed in 14 out of the 19 strains examined. These belonged to the genera Aplanochytrium, Botryochytrium, Oblongichytrium, Parietichytrium, Schizochytrium, Sicyoidochytrium, Thraustochytrium and Ulkenia. On the other hand, cellulolytic enzyme activity was not detected in any strains belonging to the genus Aurantiochytrium.

Genetic characterization of Streptococcus phocae strains isolated from Atlantic salmon, Salmo salar L., in Chile.

PubMed

Valdés, I; Jaureguiberry, B; Romalde, J L; Toranzo, A E; Magariños, B; Avendaño-Herrera, R

2009-04-01

Streptococcus phocae is a beta-haemolytic bacterium frequently involved in disease outbreaks in seals causing pneumonia or respiratory infection. Since 1999, this pathogen has been isolated from diseased Atlantic salmon, Salmo salar, causing serious economic losses in the salmon industry in Chile. In this study, we used different molecular typing methods, such as pulsed-field gel electrophoresis (PFGE), randomly amplified polymorphic DNA (RAPD), enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR), repetitive extragenic palindromic PCR (REP-PCR) and restriction of 16S-23S rDNA intergenic spacer regions to evaluate the genetic diversity in S. phocae. Thirty-four strains isolated in different years were analysed. The S. phocae type strain ATCC 51973(T) was included for comparative purposes. The results demonstrated genetic homogeneity within the S. phocae strains isolated in Chile over several years, suggesting the existence of clonal relationships among S. phocae isolated from Atlantic salmon. The type strain ATCC 51973(T) presented a different genetic pattern with the PFGE, RAPD, ERIC-PCR and REP-PCR methods. However, the fingerprint patterns of two seal isolates were distinct from those of the type strain.

Phenotypic Characteristics Associated with Virulence of Clinical Isolates from the Sporothrix Complex

PubMed Central

Almeida-Paes, Rodrigo; de Oliveira, Luã Cardoso; Oliveira, Manoel Marques Evangelista; Gutierrez-Galhardo, Maria Clara; Nosanchuk, Joshua Daniel; Zancopé-Oliveira, Rosely Maria

2015-01-01

The Sporothrix complex members cause sporotrichosis, a subcutaneous mycosis with a wide spectrum of clinical manifestations. Several specific phenotypic characteristics are associated with virulence in many fungi, but studies in this field involving the Sporothrix complex species are scarce. Melanization, thermotolerance, and production of proteases, catalase, and urease were investigated in 61 S. brasiliensis, one S. globosa, and 10 S. schenckii strains. The S. brasiliensis strains showed a higher expression of melanin and urease compared with S. schenckii. These two species, however, presented similar thermotolerances. Our S. globosa strain had low expression of all studied virulence factors. The relationship between these phenotypes and clinical aspects of sporotrichosis was also evaluated. Strains isolated from patients with spontaneous regression of infection were heavily melanized and produced high urease levels. Melanin was also related to dissemination of internal organs and protease production was associated with HIV-coinfection. A murine sporotrichosis model showed that a S. brasiliensis strain with high expression of virulence factors was able to disseminate and yield a high fungal burden in comparison with a control S. schenckii strain. Our results show that virulence-related phenotypes are variably expressed within the Sporothrix complex species and might be involved in clinical aspects of sporotrichosis. PMID:25961005

Algoriphagus aestuarii sp. nov., a member of the Cyclobacteriaceae isolated from a tidal-flat sediment of the Yellow Sea in Korea.

PubMed

Jung, Yong-Taek; Lee, Jung-Sook; Yoon, Jung-Hoon

2015-10-01

A Gram-strain-negative, coccoid or oval-shaped, non-motile bacterial strain, designated MDM-1T, was isolated from a tidal-flat sediment on the Korean peninsula. Strain MDM-1T was found to grow optimally at pH 7.0-8.0, at 30 °C and in the presence of 2-3 % (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences showed that strain MDM-1T falls within the clade comprising species of the genus Algoriphagus, clustering with the type strains of Algoriphagus halophilus, A. lutimaris, A. chungangensis and A. machipongonensis, with which it exhibited 97.2-98.5 % 16S rRNA gene sequence similarity. Sequence similarities to the type strains of the other recognized species of the genus Algoriphagus were 92.8-97.6 %. Strain MDM-1T was found to contain MK-7 as the predominant menaquinone and iso-C15 : 0 and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c) as the major fatty acids. The major polar lipids were identified as phosphatidylcholine, phosphatidylethanolamine and two unidentified lipids. The DNA G+C content of strain MDM-1T was determined to be 42.7 mol% and the mean DNA-DNA relatedness with A. halophilus KCTC 12051T, A. lutimaris S1-3T, A. chungangensis KCTC 23759T, A. machipongonensis DSM 24695T and A. ratkowskyi CIP 107452T was 19.7-5.2 %. Differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain MDM-1T is distinguishable from recognized species of the genus Algoriphagus. On the basis of the data presented, strain MDM-1T is proposed to represent a novel species of the genus Algoriphagus, for which the name Algoriphagus aestuarii sp. nov. is proposed. The type strain is MDM-1T ( = KCTC 42199T = NBRC 110552T).

Comparative genomics analysis of Streptococcus agalactiae reveals that isolates from cultured tilapia in China are closely related to the human strain A909.

PubMed

Liu, Guangjin; Zhang, Wei; Lu, Chengping

2013-11-11

Streptococcus agalactiae, also referred to as Group B Streptococcus (GBS), is a frequent resident of the rectovaginal tract in humans, and a major cause of neonatal infection. In addition, S. agalactiae is a known fish pathogen, which compromises food safety and represents a zoonotic hazard. The complete genome sequence of the piscine S. agalactiae isolate GD201008-001 was compared with 14 other piscine, human and bovine strains to explore their virulence determinants, evolutionary relationships and the genetic basis of host tropism in S. agalactiae. The pan-genome of S. agalactiae is open and its size increases with the addition of newly sequenced genomes. The core genes shared by all isolates account for 50 ~ 70% of any single genome. The Chinese piscine isolates GD201008-001 and ZQ0910 are phylogenetically distinct from the Latin American piscine isolates SA20-06 and STIR-CD-17, but are closely related to the human strain A909, in the context of the clustered regularly interspaced short palindromic repeats (CRISPRs), prophage, virulence-associated genes and phylogenetic relationships. We identified a unique 10 kb gene locus in Chinese piscine strains. Isolates from cultured tilapia in China have a close genomic relationship with the human strain A909. Our findings provide insight into the pathogenesis and host-associated genome content of piscine S. agalactiae isolated in China.

Comparative genomics of Vibrio cholerae El Tor strains isolated at epidemic complications in Siberia and at the Far East.

PubMed

Mironova, Liliya V; Gladkikh, Anna S; Ponomareva, Anna S; Feranchuk, Sergey I; Bochalgin, Nikita О; Basov, Evgenii A; Yu Khunkheeva, Zhanna; Balakhonov, Sergey V

2018-06-01

The territory of Siberia and the Far East of Russia is classified as epidemically safe for cholera; however, in the 1970s and 1990s a number of infection importation cases and acute outbreaks associated with the cholera importation were reported. Here, we analyze genomes of four Vibrio cholerae El Tor strains isolated from humans during epidemic complications (imported cases, an outbreak) in the 1990s. The analyzed strains harbor the classical allele of the cholera toxin subunit B gene (ctxB1); thus, belong to genetically altered variants of the El Tor biotype. Analysis of the genomes revealed their high homology with the V. cholerae N16961 reference strain: 85-93 SNPs were identified in the core genome as compared to the reference. The determined features of SNPs in the CTX prophage made it possible to propose the presence of a new subtype - CTX-2a in two strains; the other two strains carried the prophage of CTX-3 type. Results of phylogenetic analysis based on SNP-typing demonstrated that two strains belonged to the second wave, and two - to the early third wave of cholera dissemination in the world. Phylogenetic reconstruction in combination with epidemiological data permitted to trace the origin of the strains and the way of their importation to the Russian Federation directly or through temporary cholera foci. Copyright © 2018 Elsevier B.V. All rights reserved.

Differences in Carbohydrates Utilization and Antibiotic Resistance Between Streptococcus macedonicus and Streptococcus thermophilus Strains Isolated from Dairy Products in Italy.

PubMed

Tarrah, Armin; Treu, Laura; Giaretta, Sabrina; Duarte, Vinicius; Corich, Viviana; Giacomini, Alessio

2018-06-18

Streptococcus thermophilus and S. macedonicus are the only two species of the genus related to food productions so far known. In the present study, eight S. thermophilus and seven S. macedonicus strains isolated from dairy environments in Italy were compared in order to evidence possible species-specific technological characteristics. Their capability to use lactose, galactose, fructose, and glucose, sugars commonly present in foods and two carbohydrates considered as prebiotics, xylose and inulin, along with the respective growth kinetics were studied. Results showed a luxuriant growth on lactose and different behaviors on galactose, glucose, and fructose. No growth on inulin and xylose was recorded, which is a positive feature for strains intended to be used as starter cultures. Growth parameters, namely, λ, µ max , and N max , were estimated by using the Gompertz model. Antibiotic resistance to 14 drugs revealed an overall similar behavior between the two species with only a marked difference regarding gentamycin. Antimicrobial activity was also tested against six deleterious bacterial strains, but none of the strains evidenced inhibitory capabilities. The results presented here could be helpful to compare technological potentialities of the two species and to choose strains of the most suitable species for selected microbiological food transformations.

Lactobacillus futsaii sp. nov., isolated from fu-tsai and suan-tsai, traditional Taiwanese fermented mustard products.

PubMed

Chao, Shiou-Huei; Kudo, Yuko; Tsai, Ying-Chieh; Watanabe, Koichi

2012-03-01

Three Gram-stain-positive strains were isolated from fermented mustard and were rod-shaped, non-motile, asporogenous, facultatively anaerobic, homofermentative and did not exhibit catalase activity. Comparative analyses of 16S rRNA, pheS and rpoA gene sequences demonstrated that the novel strains were members of the genus Lactobacillus. On the basis of 16S rRNA gene sequence analysis, the type strains of Lactobacillus crustorum (98.7% similarity), Lactobacillus farciminis (98.9%) and Lactobacillus mindensis (97.9%) were the closest neighbours. However, DNA-DNA reassociation values with these strains were less than 50%. Phenotypic and genotypic features demonstrated that these isolates represent a novel species of the genus Lactobacillus, for which the name Lactobacillus futsaii sp. nov. is proposed; the type strain is YM 0097(T) (=JCM 17355(T)=BCRC 80278(T)).

Mechanical Properties of Transgenic Silkworm Silk Under High Strain Rate Tensile Loading

NASA Astrophysics Data System (ADS)

Chu, J.-M.; Claus, B.; Chen, W.

2017-12-01

Studies have shown that transgenic silkworm silk may be capable of having similar properties of spider silk while being mass-producible. In this research, the tensile stress-strain response of transgenic silkworm silk fiber is systematically characterized using a quasi-static load frame and a tension Kolsky bar over a range of strain-rates between 10^{-3} and 700/s. The results show that transgenic silkworm silk tends to have higher overall ultimate stress and failure strain at high strain rate (700/s) compared to quasi-static strain rates, indicating rate sensitivity of the material. The failure strain at the high strain rate is higher than that of spider silk. However, the stress levels are significantly below that of spider silk, and far below that of high-performance fiber. Failure surfaces are examined via scanning electron microscopy and reveal that the failure modes are similar to those of spider silk.

Erwinia amylovora CRISPR Elements Provide New Tools for Evaluating Strain Diversity and for Microbial Source Tracking

PubMed Central

McGhee, Gayle C.; Sundin, George W.

2012-01-01

Clustered regularly interspaced short palindromic repeats (CRISPRs) comprise a family of short DNA repeat sequences that are separated by non repetitive spacer sequences and, in combination with a suite of Cas proteins, are thought to function as an adaptive immune system against invading DNA. The number of CRISPR arrays in a bacterial chromosome is variable, and the content of each array can differ in both repeat number and in the presence or absence of specific spacers. We utilized a comparative sequence analysis of CRISPR arrays of the plant pathogen Erwinia amylovora to uncover previously unknown genetic diversity in this species. A total of 85 E. amylovora strains varying in geographic isolation (North America, Europe, New Zealand, and the Middle East), host range, plasmid content, and streptomycin sensitivity/resistance were evaluated for CRISPR array number and spacer variability. From these strains, 588 unique spacers were identified in the three CRISPR arrays present in E. amylovora, and these arrays could be categorized into 20, 17, and 2 patterns types, respectively. Analysis of the relatedness of spacer content differentiated most apple and pear strains isolated in the eastern U.S. from western U.S. strains. In addition, we identified North American strains that shared CRISPR genotypes with strains isolated on other continents. E. amylovora strains from Rubus and Indian hawthorn contained mostly unique spacers compared to apple and pear strains, while strains from loquat shared 79% of spacers with apple and pear strains. Approximately 23% of the spacers matched known sequences, with 16% targeting plasmids and 5% targeting bacteriophage. The plasmid pEU30, isolated in E. amylovora strains from the western U.S., was targeted by 55 spacers. Lastly, we used spacer patterns and content to determine that streptomycin-resistant strains of E. amylovora from Michigan were low in diversity and matched corresponding streptomycin-sensitive strains from the background population. PMID:22860008

Erwinia amylovora CRISPR elements provide new tools for evaluating strain diversity and for microbial source tracking.

PubMed

McGhee, Gayle C; Sundin, George W

2012-01-01

Clustered regularly interspaced short palindromic repeats (CRISPRs) comprise a family of short DNA repeat sequences that are separated by non repetitive spacer sequences and, in combination with a suite of Cas proteins, are thought to function as an adaptive immune system against invading DNA. The number of CRISPR arrays in a bacterial chromosome is variable, and the content of each array can differ in both repeat number and in the presence or absence of specific spacers. We utilized a comparative sequence analysis of CRISPR arrays of the plant pathogen Erwinia amylovora to uncover previously unknown genetic diversity in this species. A total of 85 E. amylovora strains varying in geographic isolation (North America, Europe, New Zealand, and the Middle East), host range, plasmid content, and streptomycin sensitivity/resistance were evaluated for CRISPR array number and spacer variability. From these strains, 588 unique spacers were identified in the three CRISPR arrays present in E. amylovora, and these arrays could be categorized into 20, 17, and 2 patterns types, respectively. Analysis of the relatedness of spacer content differentiated most apple and pear strains isolated in the eastern U.S. from western U.S. strains. In addition, we identified North American strains that shared CRISPR genotypes with strains isolated on other continents. E. amylovora strains from Rubus and Indian hawthorn contained mostly unique spacers compared to apple and pear strains, while strains from loquat shared 79% of spacers with apple and pear strains. Approximately 23% of the spacers matched known sequences, with 16% targeting plasmids and 5% targeting bacteriophage. The plasmid pEU30, isolated in E. amylovora strains from the western U.S., was targeted by 55 spacers. Lastly, we used spacer patterns and content to determine that streptomycin-resistant strains of E. amylovora from Michigan were low in diversity and matched corresponding streptomycin-sensitive strains from the background population.

Reappraisal of the taxonomy of Streptococcus suis serotypes 20, 22 and 26: Streptococcus parasuis sp. nov.

PubMed

Nomoto, R; Maruyama, F; Ishida, S; Tohya, M; Sekizaki, T; Osawa, Ro

2015-02-01

In order to clarify the taxonomic position of serotypes 20, 22 and 26 of Streptococcus suis, biochemical and molecular genetic studies were performed on isolates (SUT-7, SUT-286(T), SUT-319, SUT-328 and SUT-380) reacted with specific antisera of serotypes 20, 22 or 26 from the saliva of healthy pigs as well as reference strains of serotypes 20, 22 and 26. Comparative recN gene sequencing showed high genetic relatedness among our isolates, but marked differences from the type strain S. suis NCTC 10234(T), i.e. 74.8-75.7 % sequence similarity. The genomic relatedness between the isolates and other strains of species of the genus Streptococcus, including S. suis, was calculated using the average nucleotide identity values of whole genome sequences, which indicated that serotypes 20, 22 and 26 should be removed taxonomically from S. suis and treated as a novel genomic species. Comparative sequence analysis revealed 99.0-100 % sequence similarities for the 16S rRNA genes between the reference strains of serotypes 20, 22 and 26, and our isolates. Isolate STU-286(T) had relatively high 16S rRNA gene sequence similarity with S. suis NCTC 10234(T) (98.8 %). SUT-286(T) could be distinguished from S. suis and other closely related species of the genus Streptococcus using biochemical tests. Due to its phylogenetic and phenotypic similarities to S. suis we propose naming the novel species Streptococcus parasuis sp. nov., with SUT-286(T) ( = JCM 30273(T) = DSM 29126(T)) as the type strain. © 2015 IUMS.

Characterization of fatty acid modifying enzyme activity in staphylococcal mastitis isolates and other bacteria

PubMed Central

2012-01-01

Background Fatty acid modifying enzyme (FAME) has been shown to modify free fatty acids to alleviate their bactericidal effect by esterifying fatty acids to cholesterol or alcohols. Although it has been shown in previous studies that FAME is required for Staphylococcus aureus survival in skin abscesses, FAME is poorly studied compared to other virulence factors. FAME activity had also been detected in coagulase-negative staphylococci (CNS). However, FAME activity was only surveyed after a bacterial culture was grown for 24 h. Therefore if FAME activity was earlier in the growth phase, it would not have been detected by the assay and those strains would have been labeled as FAME negative. Results Fifty CNS bovine mastitis isolates and several S. aureus, Escherichia coli, and Streptococcus uberis strains were assayed for FAME activity over 24 h. FAME activity was detected in 54% of CNS and 80% S. aureus strains surveyed but none in E. coli or S. uberis. While some CNS strains produced FAME activity comparable to the lab strain of S. aureus, the pattern of FAME activity varied among strains and across species of staphylococci. All CNS that produced FAME activity also exhibited lipase activity. Lipase activity relative to colony forming units of these CNS decreased over the 24 h growth period. No relationship was observed between somatic cell count in the milk and FAME activity in CNS. Conclusions Some staphylococcal species surveyed produced FAME activity, but E. coli and S. uberis strains did not. All FAME producing CNS exhibited lipase activity which may indicate that both these enzymes work in concert to alter fatty acids in the bacterial environment. PMID:22726316

Aerobic Hydrogen Production via Nitrogenase in Azotobacter vinelandii CA6

PubMed Central

Noar, Jesse; Loveless, Telisa; Navarro-Herrero, José Luis; Olson, Jonathan W.

2015-01-01

The diazotroph Azotobacter vinelandii possesses three distinct nitrogenase isoenzymes, all of which produce molecular hydrogen as a by-product. In batch cultures, A. vinelandii strain CA6, a mutant of strain CA, displays multiple phenotypes distinct from its parent: tolerance to tungstate, impaired growth and molybdate transport, and increased hydrogen evolution. Determining and comparing the genomic sequences of strains CA and CA6 revealed a large deletion in CA6's genome, encompassing genes related to molybdate and iron transport and hydrogen reoxidation. A series of iron uptake analyses and chemostat culture experiments confirmed iron transport impairment and showed that the addition of fixed nitrogen (ammonia) resulted in cessation of hydrogen production. Additional chemostat experiments compared the hydrogen-producing parameters of different strains: in iron-sufficient, tungstate-free conditions, strain CA6's yields were identical to those of a strain lacking only a single hydrogenase gene. However, in the presence of tungstate, CA6 produced several times more hydrogen. A. vinelandii may hold promise for developing a novel strategy for production of hydrogen as an energy compound. PMID:25911479

The molecular identification of Streptococcus equi subsp. equi strains isolated within New Zealand.

PubMed

Patty, O A; Cursons, R T M

2014-03-01

To identify Streptococcus equi subsp. equi (S. equi) by PCR analysis and obtain isolates by culture, in order to investigate the strains of S. equi infecting horses within New Zealand. A diagnostic PCR, based on the amplification of the seeI gene for S. equi, was used on 168 samples submitted from horses with and without clinical signs of strangles. Samples were also processed and cultured on selective media for the isolation of β-haemolytic colonies. In addition, the hypervariable region of the seM gene of S. equi was amplified and then sequenced for strain typing purposes. Of the 168 samples, 35 tested positive for S. equi using PCR. Thirty-two confirmed samples were from horses with a clinical diagnosis of strangles and three were from horses where clinical information was unavailable. Only 22/35 (63%) confirmed S. equi samples were successfully isolated following culture. Strain typing demonstrated that two novel seM alleles of S. equi were found in New Zealand with SeM-99 strains being restricted to the North Island while SeM-100 strains were found in both North and South Islands. The application of PCR for the laboratory confirmation of strangles allowed for a rapid and sensitive identification of S. equi. Moreover, seM typing revealed that within the samples examined two strains of S. equi co-circulated within the North Island of New Zealand but only one strain in the South Island. PCR reduces the time required to obtain laboratory confirmation of strangles compared with culture methods. It also has greater sensitivity in detecting S. equi infections, which is of particular importance in the detection of carrier animals which normally shed low numbers of bacteria. Additionally, seM molecular typing can differentiate between bacterial strains, assisting in the monitoring of local strains of S. equi subsp. equi causing disease.

Variable characteristics of bacteriocin-producing Streptococcus salivarius strains isolated from Malaysian subjects.

PubMed

Barbour, Abdelahhad; Philip, Koshy

2014-01-01

Salivaricins are bacteriocins produced by Streptococcus salivarius, some strains of which can have significant probiotic effects. S. salivarius strains were isolated from Malaysian subjects showing variable antimicrobial activity, metabolic profile, antibiotic susceptibility and lantibiotic production. In this study we report new S. salivarius strains isolated from Malaysian subjects with potential as probiotics. Safety assessment of these strains included their antibiotic susceptibility and metabolic profiles. Genome sequencing using Illumina's MiSeq system was performed for both strains NU10 and YU10 and demonstrating the absence of any known streptococcal virulence determinants indicating that these strains are safe for subsequent use as probiotics. Strain NU10 was found to harbour genes encoding salivaricins A and 9 while strain YU10 was shown to harbour genes encoding salivaricins A3, G32, streptin and slnA1 lantibiotic-like protein. Strain GT2 was shown to harbour genes encoding a large non-lantibiotic bacteriocin (salivaricin-MPS). A new medium for maximum biomass production buffered with 2-(N-morpholino)ethanesulfonic acid (MES) was developed and showed better biomass accumulation compared with other commercial media. Furthermore, we extracted and purified salivaricin 9 (by strain NU10) and salivaricin G32 (by strain YU10) from S. salivarius cells grown aerobically in this medium. In addition to bacteriocin production, S. salivarius strains produced levan-sucrase which was detected by a specific ESI-LC-MS/MS method which indicates additional health benefits from the developed strains. The current study established the bacteriocin, levan-sucrase production and basic safety features of S. salivarius strains isolated from healthy Malaysian subjects demonstrating their potential for use as probiotics. A new bacteriocin-production medium was developed with potential scale up application for pharmaceuticals and probiotics from S. salivarius generating different lantibiotics. This is relevant for the clinical management of oral cavity and upper respiratory tract in the human population.

The abundance of cis-acting loci leading to differential allele expression in F1 mice and their relationship to loci harboring genes affecting complex traits.

PubMed

Yeo, Seungeun; Hodgkinson, Colin A; Zhou, Zhifeng; Jung, Jeesun; Leung, Ming; Yuan, Qiaoping; Goldman, David

2016-08-11

Genome-wide surveys have detected cis-acting quantitative trait loci altering levels of RNA transcripts (RNA-eQTLs) by associating SNV alleles to transcript levels. However, the sensitivity and specificity of detection of cis- expression quantitative trait loci (eQTLs) by genetic approaches, reliant as it is on measurements of transcript levels in recombinant inbred strains or offspring from arranged crosses, is unknown, as is their relationship to QTL's for complex phenotypes. We used transcriptome-wide differential allele expression (DAE) to detect cis-eQTLs in forebrain and kidney from reciprocal crosses between three mouse inbred strains, 129S1/SvlmJ, DBA/2J, and CAST/EiJ and C57BL/6 J. Two of these crosses were previously characterized for cis-eQTLs and QTLs for various complex phenotypes by genetic analysis of recombinant inbred (RI) strains. 5.4 %, 1.9 % and 1.5 % of genes assayed in forebrain of B6/129SF1, B6/DBAF1, and B6/CASTF1 mice, respectively, showed differential allelic expression, indicative of cis-acting alleles at these genes. Moreover, the majority of DAE QTLs were observed to be tissue-specific with only a small fraction showing cis-effects in both tissues. Comparing DAE QTLs in F1 mice to cis-eQTLs previously mapped in RI strains we observed that many of the cis-eQTLs were not confirmed by DAE. Additionally several novel DAE-QTLs not identified as cis-eQTLs were identified suggesting that there are differences in sensitivity and specificity for QTL detection between the two methodologies. Strain specific DAE QTLs in B6/DBAF1 mice were located in excess at candidate genes for alcohol use disorders, seizures, and angiogenesis previously implicated by genetic linkage in C57BL/6J × DBA/2JF2 mice or BXD RI strains. Via a survey for differential allele expression in F1 mice, a substantial proportion of genes were found to have alleles altering expression in cis-acting fashion. Comparing forebrain and kidney, many or most of these alleles were tissue-specific in action. The identification of strain specific DAE QTLs, can assist in assessment of candidate genes located within the large intervals associated with trait QTLs.

Identification of Motile Aeromonas Strains with the MicroScan WalkAway System in Conjunction with the Combo Negative Type 1S Panels

PubMed Central

Vivas, J.; Sáa, A. I.; Tinajas, A.; Barbeyto, L.; Rodríguez, L. A.

2000-01-01

This study was performed to compare the MicroScan WalkAway automated identification system in conjunction with the new MicroScan Combo Negative type 1S panels with conventional biochemical methods for identifying 85 environmental, clinical, and reference strains of eight Aeromonas species. PMID:10742279

Anti-listerial Bactericidal Activity of Lactobacillus plantarum DM5 Isolated from Fermented Beverage Marcha.

PubMed

Das, Deeplina; Goyal, Arun

2013-09-01

The strain Lactobacillus plantarum DM5 was isolated from fermented beverage Marcha of Sikkim and explored for its antagonistic activity against food-borne pathogens. The cell-free supernatant of L. plantarum DM5 showed antibacterial activity of 6,400 AU/mL in MRS medium (pH 6.0) against the indicator strain Staphylococcus aureus. MRS medium supplemented with 15 g/L of maltose at 37 °C under static condition yielded highest antimicrobial activity (6,400 AU/mL) with 3 % increase in specific activity when compared to 20 g/L glucose. The antimicrobial compound was heat stable (60 min at 100 °C) and was active over a wide pH range. It showed bactericidal effect on S. aureus and Listeria monocytogenes by causing 96 and 98 % of cell lysis, respectively. The cell morphology of the treated S. aureus and L. monocytogenes was completely deformed as revealed by scanning electron microscopy, suggesting the high potential of L. plantarum DM5 as natural preservatives in food industry. The antimicrobial compound was purified by 80 % ammonium sulphate precipitation and showed antimicrobial activity of 12,800 AU/mL with 19-fold purification and a molecular mass of 15.2 kDa, indicating the proteinaceous nature of the compound.

Molecular characterization of infectious bursal disease virus isolates from Nepal based on hypervariable region of VP2 gene.

PubMed

Sharma, K; Hair-Bejo, M; Omar, A R; Aini, I

2005-01-01

Two Infectious bursal disease virus (IBDV) isolates, NP1SSH and NP2K were obtained from a severe infectious bursal disease (IBD) outbreak in Nepal in 2002. The hypervariable (HV) region of VP2 gene (1326 bp) of the isolates was generated by RT-PCR and sequenced. The obtained nucleotide sequences were compared with those of twenty other IBDV isolates/strains. Phylogenetic analysis based on this comparison revealed that NP1SSH and NP2K clustered with very virulent (vv) IBDV strains of serotype 1. In contrast, classical, Australian classical and attenuated strains of serotype 1 and avirulent IBDV strains of serotype 2 formed a different cluster. The deduced amino acid sequences of the two isolates showed a 98.3% identity with each other and 97.1% and 98.3% identities, respectively with very virulent IBDV (vvIBDV) isolates/strains. Three amino acids substitutions at positions 300 (E-->A), 308 (I-->F) and 334 (A-->P) within the HV region were common for both the isolates. The amino acids substitutions at positions 27 (S-->T), 28 (I-->T), 31 (D-->A), 36 (H-->Y), 135 (E-->G), 223 (G-->S), 225 (V-->I), 351 (L-->I), 352 (V-->E) and 399 (I-->S) for NP1SSH and at position 438 (I-->S) for NP2K were unique and differed from other IBDV isolates/strains. NP1SSH and NP2K showed highest similarity (97.8%) with the BD399 strain from Bangladesh as compared with other vvIBDV isolates/strains. We conclude that the NP1SSH and NP2K isolates of IBDV from Nepal represent vvIBDV of serotype 1.

Phylogenetic analysis of several Thermus strains from Rehai of Tengchong, Yunnan, China.

PubMed

Lin, Lianbing; Zhang, Jie; Wei, Yunlin; Chen, Chaoyin; Peng, Qian

2005-10-01

Several Thermus strains were isolated from 10 hot springs of the Rehai geothermal area in Tengchong, Yunnan province. The diversity of Thermus strains was examined by sequencing the 16S rRNA genes and comparing their sequences. Phylogenetic analysis showed that the 16S rDNA sequences from the Rehai geothermal isolates form four branches in the phylogenetic tree and had greater than 95.9% similarity in the phylogroup. Secondary structure comparison also indicated that the 16S rRNA from the Rehai geothermal isolates have unique secondary structure characteristics in helix 6, helix 9, and helix 10 (reference to Escherichia coli). This research is the first attempt to reveal the diversity of Thermus strains that are distributed in the Rehai geothermal area.

Near-Isogenic Cry1F-Resistant Strain of Spodoptera frugiperda (Lepidoptera: Noctuidae) to Investigate Fitness Cost Associated With Resistance in Brazil.

PubMed

Horikoshi, Renato J; Bernardi, Oderlei; Bernardi, Daniel; Okuma, Daniela M; Farias, Juliano R; Miraldo, Leonardo L; Amaral, Fernando S A; Omoto, Celso

2016-04-01

Field-evolved resistance to Cry1F maize in Spodoptera frugiperda (J.E. Smith) populations in Brazil was reported in 2014. In this study, to investigate fitness costs, we constructed a near-isogenic S. frugiperda-resistant strain (R-Cry1F) using Cry1F-resistant and Cry1F-susceptible strains sharing a close genetic background. A near-isogenic R-Cry1F strain was obtained by eight repeated backcrossings, each followed by sib-mating and selection among resistant and susceptible strains. Fitness cost parameters were evaluated by comparing the biological performance of resistant, susceptible, and heterozygous strains on artificial diet. Fitness parameters monitored included development time and survival rates of egg, larval, pupal, and egg-to-adult periods; sex ratio; adult longevity; timing of preoviposition, oviposition, and postoviposition; fecundity; and fertility. A fertility life table was also calculated. The near-isogenic R-Cry1F strain showed lower survival rate of eggs (32%), when compared with Sus and reciprocal crosses (41 and 55%, respectively). The number of R-Cry1F insects that completed the life cycle was reduced to ∼25%, compared with the Sus strain with ∼32% reaching the adult stage. The mean generation time (T) of R-Cry1F strain was ∼2 d shorter than R-Cry1F♂×Sus♀ and Sus strains. The reproductive parameters of R-Cry1F strain were similar to the Sus strain. However, fewer females were produced by R-Cry1F strain than R-Cry1F♀×Sus♂ and more females than R-Cry1F♂×Sus♀. In summary, no relevant fitness costs are observed in a near-isogenic Cry1F-resistant strain of S. frugiperda, indicating stability of resistance to Cry1F protein in Brazilian populations of this species in the absence of selection pressure.