Detoxification of cancerogenic compounds by lactic acid bacteria strains.
Lili, Zhao; Junyan, Wei; Hongfei, Zhao; Baoqing, Zhu; Bolin, Zhang
2017-10-20
Carcinogens in food are an important issue that threat people's health right now. Lactic acid bacteria (LAB) strains as well-known probiotics have shown numerous perspectives in being used as a good food additive to confront cancerogenic compounds in recent years. Some LAB strains can remove cancerogenic compounds from medium environment via direct physical binding and avoid re-pollution of poisonous secondary metabolites which are generated from degradation of cancerogenic compounds. This article presents a whole overview of the physical-binding of LAB strains to such common cancerogenic compounds existed in food and feed environments as mycotoxins, polycyclic aromatic hydrocarbons (PAHs), heterocyclic amines (HAs) and pthalic acid esters (PAEs).In most cases, summaries of these published researches show that the binding of LAB strains to cancerogenic compounds is a physical process. Binding sites generally take place in cell wall, and peptidoglycan from LAB cells is the chief binding site. The adsorption of lactic acid bacteria to cancerogenic compounds is strain-specific. Specially, the strains from the two genera Lactobacillus and Bifidobacterium show a better potential in binding cancerogenic compounds. Moreover, we firstly used molecular dynamic computer model as a highly potential tool to simulate the binding behavior of peptidoglycan from Lactobacillus acidophilus to DBP, one of pthalic acid esters with genetic toxicity. It was seen that the theoretical data were quite consistent with the experimental results in terms of the ability of this bacterium to bind DBP. Also, the toxicity reduction of cancerogenic compounds by LAB strains could be achieved either in gastrointestinal model or animal tests and clinical researches as well. In conclusion, carefully selected LAB strains should be a good solution as one of safety strategies to reduce potential risk of cancerogenic compounds from food-based products.
Characterization of Lactic Acid Bacteria (LAB) isolated from Indonesian shrimp paste (terasi)
NASA Astrophysics Data System (ADS)
Amalia, U.; Sumardianto; Agustini, T. W.
2018-02-01
Shrimp paste was one of fermented products, popular as a taste enhancer in many dishes. The processing of shrimp paste was natural fermentation, depends on shrimp it self and the presence of salt. The salt inhibits the growth of undesirable microorganism and allows the salt-tolerant lactic acid bacteria (LAB) to ferment the protein source to lactic acids. The objectives of this study were to characterize LAB isolated from Indonesian shrimp paste or "Terasi" with different times of fermentation (30, 60 and 90 days). Vitech analysis showed that there were four strains of the microorganism referred to as lactic acid bacteria (named: LABS1, LABS2, LABS3 and LABS4) with 95% sequence similarity. On the basis of biochemical, four isolates represented Lactobacillus, which the name Lactobacillus plantarum is proposed. L.plantarum was play role in resulting secondary metabolites, which gave umami flavor in shrimp paste.
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.
Bodaszewska-Lubas, Malgorzata; Brzychczy-Wloch, Monika; Gosiewski, Tomasz; Heczko, Piotr B
2012-10-25
In this paper, an attempt was made to evaluate the antibacterial potential of standard strains of lactic acid bacteria (LAB) producing bacteriocins of various classes, thus demonstrating various mechanisms of cell membrane damages against the Streptococcus agalactiae strains (Group B Streptococcus, GBS), depending on surface polysaccharides and surface alpha-like protein genes. Antimicrobial property of the strains of L. plantarum C 11, L. sakei DSMZ 6333, and L. lactis ATCC 11454 producing bacteriocins: JK and EF plantaricins, sakacin and nisin, respectively, against the GBS strains was evaluated. The chosen to the study GBS strains were represented by serotypes Ia, Ib, II, III, V and they had bca, epsilon, rib, alp2 or alp3 alpha-like protein genes. The experiment was conducted by means of suspension culture and the bacteria count was determined using the serial dilution method. A great ability of L. plantarum C 11 strain was proven to inhibit the GBS growth. The strain of L. sakei DSMZ 6333 did not demonstrate any ability to inhibit the growth of GBS, whereas L. lactis ATCC 11454 inhibited the growth of S. agalactiae indicator strains to a minor extent. Statistically significant differences were demonstrated between the GBS strains representing various serotypes against the antimicrobial activity of model LAB strains. The least sensitive to the activity of bacteriocins were the strains representing serotypes Ib and III, whereas the strains representing serotype II were the most sensitive. The sensitivity of the GBS strains to the antimicrobial activity of LAB was not dependent on alpha-like protein genes. Among the LAB standard strains producing bacteriocins, the strongest antimicrobial property was observed in the strain of L. plantarum C 11. Because of the generally known and verified strong antagonistic property of the strains of L. plantarum species against indicator bacteria, it is necessary to further pursue the research presented in this paper.
Lili, Zhao; Hongfei, Zhao; Shoukat, Sana; Xiaochen, Zhang; Bolin, Zhang
2017-06-01
Di-n-butyl phthalate (DBP) is a ubiquitous environmental contaminant that poses a risk to humans. Previous work indicates that the ability of lactic acid bacteria (LAB) to bind phthalic acid esters is strain-specific. As cell suspensions of LAB strains in aqueous solution are likely to be colloidal dispersions, this study provided a technique to efficiently screen LAB strains that bind DBP via Turbiscan, which has been widely used to measure the stability of emulsions or colloidal dispersions. Eleven LAB strains belonging to Lactobacillus plantarum, Lb. pentosus, Lb. paralimentarius, Lb. helveticus, Leuconostoc mesenteroides, Lb. acidophilus, Bifidobacterium lactis, and Bifidobacterium bifidum species were used in this study, and seven of them were selected to test in an earlier stage of exploring the process for finding a screening method; others were used for a validation test. It was observed that the various values of the 10 h Turbiscan Stability Index (TSI) of the cell suspension from each strain, at the equilibrium time of dispersed particles according to the peak thickness of cell-suspensions as measured by Turbiscan, had significant negative correlations with the DBP-binding percentage of LAB strains. Higher TSI values are correlated with lower binding of bacteria strains to DBP with a correlation coefficient of 0.8292. Cell surface hydrocarbons of LAB strains and their adherence were observed to correlate with DBP-binding percentages and may lead to the different states of aggregation or equilibrium of bacterial cell-suspensions, and the aggregation of bacterial cells resulted in fewer binding sites in the cell wall for DBP. Finally, four LAB strains were randomly selected to verify the feasibility of the method. In all, the findings demonstrate that TSI might be used as a tool to quickly screen strains that bind DBP. The present work could be extended to the removal of other toxic compounds, when screening of high-efficiency strains is required.
Lefeber, Timothy; Janssens, Maarten; Camu, Nicholas; De Vuyst, Luc
2010-12-01
The composition of cocoa pulp simulation media (PSM) was optimized with species-specific strains of lactic acid bacteria (PSM-LAB) and acetic acid bacteria (PSM-AAB). Also, laboratory fermentations were carried out in PSM to investigate growth and metabolite production of strains of Lactobacillus plantarum and Lactobacillus fermentum and of Acetobacter pasteurianus isolated from Ghanaian cocoa bean heap fermentations, in view of the development of a defined starter culture. In a first step, a selection of strains was made out of a pool of strains of these LAB and AAB species, obtained from previous studies, based on their fermentation kinetics in PSM. Also, various concentrations of citric acid in the presence of glucose and/or fructose (PSM-LAB) and of lactic acid in the presence of ethanol (PSM-AAB) were tested. These data could explain the competitiveness of particular cocoa-specific strains, namely, L. plantarum 80 (homolactic and acid tolerant), L. fermentum 222 (heterolactic, citric acid fermenting, mannitol producing, and less acid tolerant), and A. pasteurianus 386B (ethanol and lactic acid oxidizing, acetic acid overoxidizing, acid tolerant, and moderately heat tolerant), during the natural cocoa bean fermentation process. For instance, it turned out that the capacity to use citric acid, which was exhibited by L. fermentum 222, is of the utmost importance. Also, the formation of mannitol was dependent not only on the LAB strain but also on environmental conditions. A mixture of L. plantarum 80, L. fermentum 222, and A. pasteurianus 386B can now be considered a mixed-strain starter culture for better controlled and more reliable cocoa bean fermentation processes.
Lactic acid bacteria from raw milk as potentially beneficial strains to prevent bovine mastitis.
Espeche, M Carolina; Pellegrino, Matías; Frola, Ignacio; Larriestra, Alejandro; Bogni, Cristina; Nader-Macías, M E Fátima
2012-02-01
Bovine mastitis produces a wide variety of problems in the dairy farm. The treatment of this disease is based on the use of antibiotics which are not always effective. These drugs are also responsible for the presence of residues in the milk and the increase of antibiotic-resistant strains. Probiotic products were proposed as a valid alternative to antibiotic therapies and are also useful for the prevention of infectious syndromes. With the aim of designing a probiotic product to prevent bovine mastitis, lactic acid bacteria (LAB) were isolated from foremilk samples from different dairy farms in Córdoba-Argentina. One hundred and seventeen LAB were isolated and their beneficial characteristics such as the production of inhibitory substances, surface properties and production of exopolysaccharides (EPS) were assessed. Most of them displayed low degree of hydrophobicity, autoaggregation, EPS negative phenotype and were identified as Enterococcus hirae and Pediococcus pentosaceus. Nine LAB strains inhibited three indicator bacteria. Some isolates were pre-selected and genetically identified according to the results obtained. Antibiotic resistance and virulence factors were studied for the assessment of the safety of the strains. The results obtained were compared to those reported previously from samples obtained in the North-western area of the country and some differences were found. Copyright © 2012 Elsevier Ltd. All rights reserved.
Lefeber, Timothy; Janssens, Maarten; Camu, Nicholas; De Vuyst, Luc
2010-01-01
The composition of cocoa pulp simulation media (PSM) was optimized with species-specific strains of lactic acid bacteria (PSM-LAB) and acetic acid bacteria (PSM-AAB). Also, laboratory fermentations were carried out in PSM to investigate growth and metabolite production of strains of Lactobacillus plantarum and Lactobacillus fermentum and of Acetobacter pasteurianus isolated from Ghanaian cocoa bean heap fermentations, in view of the development of a defined starter culture. In a first step, a selection of strains was made out of a pool of strains of these LAB and AAB species, obtained from previous studies, based on their fermentation kinetics in PSM. Also, various concentrations of citric acid in the presence of glucose and/or fructose (PSM-LAB) and of lactic acid in the presence of ethanol (PSM-AAB) were tested. These data could explain the competitiveness of particular cocoa-specific strains, namely, L. plantarum 80 (homolactic and acid tolerant), L. fermentum 222 (heterolactic, citric acid fermenting, mannitol producing, and less acid tolerant), and A. pasteurianus 386B (ethanol and lactic acid oxidizing, acetic acid overoxidizing, acid tolerant, and moderately heat tolerant), during the natural cocoa bean fermentation process. For instance, it turned out that the capacity to use citric acid, which was exhibited by L. fermentum 222, is of the utmost importance. Also, the formation of mannitol was dependent not only on the LAB strain but also on environmental conditions. A mixture of L. plantarum 80, L. fermentum 222, and A. pasteurianus 386B can now be considered a mixed-strain starter culture for better controlled and more reliable cocoa bean fermentation processes. PMID:20889778
NASA Astrophysics Data System (ADS)
Hidayat, Habibi
2017-03-01
16S rRNA gene analysis of bacteria lactic acid (LAB) isolate from Markisa Kuning Fruit (Passiflora edulis var. flavicarpa) as a producer of protease enzyme and probiotics has been done. The aim of the study is to determine the protease enzyme activity and 16S rRNA gene amplification using PCR. The calculation procedure was done to M4 isolate bacteria lactic acid (LAB) Isolate which has been resistant to acids with pH 2.0 in the manner of screening protease enzyme activity test result 6.5 to clear zone is 13 mm againts colony diametre is 2 mm. The results of study enzyme activity used spectrophotometer UV-Vis obtainable the regression equation Y=0.02983+0.001312X, with levels of protein M4 isolate is 0.6594 mg/mL and enzyme activity of obtainable is 0.8626 unit/ml while the spesific enzyme activity produced is 1.308 unit/mg. Then, 16S rRNA gene amplificatiom and DNA sequencing has been done. The results of study showed that the bacteria species contained from M4 bacteria lactic acid (LAB) isolate is Weisella cibiria strain II-I-59. Weisella cibiria strain II-I-59 is one of bacteria could be utilized in the digestive tract.
Novel bacteriocins from lactic acid bacteria (LAB): various structures and applications
2014-01-01
Bacteriocins are heat-stable ribosomally synthesized antimicrobial peptides produced by various bacteria, including food-grade lactic acid bacteria (LAB). These antimicrobial peptides have huge potential as both food preservatives, and as next-generation antibiotics targeting the multiple-drug resistant pathogens. The increasing number of reports of new bacteriocins with unique properties indicates that there is still a lot to learn about this family of peptide antibiotics. In this review, we highlight our system of fast tracking the discovery of novel bacteriocins, belonging to different classes, and isolated from various sources. This system employs molecular mass analysis of supernatant from the candidate strain, coupled with a statistical analysis of their antimicrobial spectra that can even discriminate novel variants of known bacteriocins. This review also discusses current updates regarding the structural characterization, mode of antimicrobial action, and biosynthetic mechanisms of various novel bacteriocins. Future perspectives and potential applications of these novel bacteriocins are also discussed. PMID:25186038
Novel bacteriocins from lactic acid bacteria (LAB): various structures and applications.
Perez, Rodney H; Zendo, Takeshi; Sonomoto, Kenji
2014-08-29
Bacteriocins are heat-stable ribosomally synthesized antimicrobial peptides produced by various bacteria, including food-grade lactic acid bacteria (LAB). These antimicrobial peptides have huge potential as both food preservatives, and as next-generation antibiotics targeting the multiple-drug resistant pathogens. The increasing number of reports of new bacteriocins with unique properties indicates that there is still a lot to learn about this family of peptide antibiotics. In this review, we highlight our system of fast tracking the discovery of novel bacteriocins, belonging to different classes, and isolated from various sources. This system employs molecular mass analysis of supernatant from the candidate strain, coupled with a statistical analysis of their antimicrobial spectra that can even discriminate novel variants of known bacteriocins. This review also discusses current updates regarding the structural characterization, mode of antimicrobial action, and biosynthetic mechanisms of various novel bacteriocins. Future perspectives and potential applications of these novel bacteriocins are also discussed.
Pellegrino, Matías S; Frola, Ignacio D; Natanael, Berardo; Gobelli, Dino; Nader-Macias, María E F; Bogni, Cristina I
2018-01-02
Bovine mastitis causes economic losses on dairy farms worldwide. Lactic acid bacteria (LAB) in animal health are an alternative tool to avoid antibiotic therapy on the prevention of bovine mastitis. In previous studies, 12 LAB isolated from bovine milk were selected taking into account some of the following characteristics: hydrophobicity, auto aggregative capability, inhibition of indicator pathogens, hydrogen peroxide, and capsular polysaccharide production. These LAB were considered because of their beneficial properties. In this work, we also analyzed the antimicrobial activity and the co-aggregation against mastitis causing bacteria, auto-inhibition, adhesion to bovine teat canal epithelial cells (BTCEC), and growth kinetic curves for the 12 LAB. Two of them, Lactococcus lactis subsp. lactis CRL 1655 and Lactobacillus perolens CRL 1724, were selected because they had an interesting pattern of adhesion to BTEC, the inhibition of pathogens and the co-aggregation with the 100% of the assayed pathogens. They showed a predictable difference in the PFGE genomic pattern bands. The kinetic growth of these two strains was similar between them and with the rest of the assayed LAB. The strains selected in the present study showed indispensable characteristics for their inclusion in a probiotic formulation to be used at dry-off period for the prevention of bovine mastitis.
Garcia, Estefânia F.; Luciano, Winnie A.; Xavier, Danilo E.; da Costa, Whyara C. A.; de Sousa Oliveira, Kleber; Franco, Octávio L.; de Morais Júnior, Marcos A.; Lucena, Brígida T. L.; Picão, Renata C.; Magnani, Marciane; Saarela, Maria; de Souza, Evandro L.
2016-01-01
This study aimed to identify lactic acid bacteria (LAB) in byproducts of fruit (Malpighia glabra L., Mangifera indica L., Annona muricata L., and Fragaria vesca L.) pulp processing. Fifty strains of LAB were identified using matrix-assisted laser desorption/ionization–time of flight mass spectrometry (MALDI-TOF MS) and 16S rRNA gene sequence (16S rRNA) analysis. Species belonging to Lactobacillus genus were the predominant LAB in all fruit pulp processing byproducts. The average congruency between the MALDI-TOF MS and 16S rRNA in LAB species identification reached 86%. Isolates of L. plantarum, L. brevis, L. pentosus, L. lactis and L. mesenteroides were identified with 100% congruency. MALDI-TOF MS and 16S rRNA analysis presented 86 and 100% efficiency of LAB species identification, respectively. Further, five selected Lactobacillus strains (L. brevis 59, L. pentosus 129, L. paracasei 108, L. plantarum 49, and L. fermentum 111) were evaluated for desirable probiotic-related properties and growth behavior on two different cultivation media. The exposure to pH 2.0 sharply decreased the counts of the different Lactobacillus strains after a 1 or 2 h incubation, while varied decreases were noted after 3 h of exposure to pH 3.0. Overall, the exposure to pH 5.0 and to bile salts (0.15, 0.30, and 1.00%) did not decrease the counts of the Lactobacillus strains. All tested Lactobacillus strains presented inhibitory activity against Staphylococcus aureus, Salmonella Typhimurium, Salmonella Enteritidis, Listeria monocytogenes and Escherichia coli, and presented variable susceptibility to different antibiotics. The selected Lactobacillus strains presented satisfactory and reproducible growth behavior. In conclusion, MALDI-TOF MS and 16S rRNA analysis revealed high efficiency and congruency for LAB species identification, and the selected Lactobacillus strains may be candidates for further investigation of novel probiotic strains. PMID:27625647
Application of Lactic Acid Bacteria (LAB) in freshness keeping of tilapia fillets as sashimi
NASA Astrophysics Data System (ADS)
Cao, Rong; Liu, Qi; Chen, Shengjun; Yang, Xianqing; Li, Laihao
2015-08-01
Aquatic products are extremely perishable food commodities. Developing methods to keep the freshness of fish represents a major task of the fishery processing industry. Application of Lactic Acid Bacteria (LAB) as food preservative is a novel approach. In the present study, the possibility of using lactic acid bacteria in freshness keeping of tilapia fillets as sashimi was examined. Fish fillets were dipped in Lactobacillus plantarum 1.19 (obtained from China General Microbiological Culture Collection Center) suspension as LAB-treated group. Changes in K-value, APC, sensory properties and microbial flora were analyzed. Results showed that LAB treatment slowed the increase of K-value and APC in the earlier storage, and caused a smooth decrease in sensory score. Gram-negative bacteria dominated during refrigerated storage, with Pseudomonas and Aeromonas being relatively abundant. Lactobacillus plantarum 1.19 had no obvious inhibitory effect against these Gram-negatives. However, Lactobacillus plantarum 1.19 changed the composition of Gram-positive bacteria. No Micrococcus were detected and the proportion of Staphylococcus decreased in the spoiled LAB-treated samples. The period that tilapia fillets could be used as sashimi material extended from 24 h to 48 h after LAB treatment. The potential of using LAB in sashimi processing was confirmed.
Diversity of predominant lactic acid bacteria associated with cocoa fermentation in Nigeria.
Kostinek, Melanie; Ban-Koffi, Louis; Ottah-Atikpo, Margaret; Teniola, David; Schillinger, Ulrich; Holzapfel, Wilhelm H; Franz, Charles M A P
2008-04-01
The fermentation of cocoa relies on a complex succession of bacteria and filamentous fungi, all of which can have an impact on cocoa flavor. So far, few investigations have focused on the diversity of lactic acid bacteria involved in cocoa fermentation, and many earlier investigations did not rely on polyphasic taxonomical approaches, which take both phenotypic and genotypic characterization techniques into account. In our study, we characterized predominant lactic acid bacteria from cocoa fermentations in Nigeria, using a combination of phenotypic tests, repetitive extragenic palindromic PCR, and sequencing of the 16S rRNA gene of representative strains for accurate species identification. Thus, of a total of 193 lactic acid bacteria (LAB) strains isolated from common media used to cultivate LAB, 40 (20.7%) were heterofermentative and consisted of either L. brevis or L. fermentum strains. The majority of the isolates were homofermentative rods (110 strains; 57% of isolates) which were characterized as L. plantarum strains. The homofermentative cocci consisted predominantly of 35 (18.1% of isolates) Pediococcus acidilactici strains. Thus, the LAB populations derived from these media in this study were accurately described. This can contribute to the further assessment of the effect of common LAB strains on the flavor characteristics of fermenting cocoa in further studies.
Wang, Ling; Wang, Zhouli; Yuan, Yahong; Cai, Rui; Niu, Chen; Yue, Tianli
2015-01-01
The purpose of this study was to identify the key factors involved in patulin adsorption by heat-inactivated lactic acid bacteria (LAB) cells. For preventing bacterial contamination, a sterilization process was involved in the adsorption process. The effects of various physical, chemical, and enzymatic pre-treatments, simultaneous treatments, and post-treatments on the patulin adsorption performances of six LAB strains were evaluated. The pre-treated cells were characterized by scanning electron microscopy (SEM). Results showed that the removal of patulin by viable cells was mainly based on adsorption or degradation, depending on the specific strain. The adsorption abilities were widely increased by NaOH and esterification pre-treatments, and reduced by trypsin, lipase, iodate, and periodate pre-treatments. Additionally, the adsorption abilities were almost maintained at pH 2.2-4.0, and enhanced significantly at pH 4.0-6.0. The effects of sodium and magnesium ions on the adsorption abilities at pH 4 were slight and strain-specific. A lower proportion of patulin was released from the strain with higher adsorption ability. Analyses revealed that the physical structure of peptidoglycan was not a principal factor. Vicinal OH and carboxyl groups were not involved in patulin adsorption, while alkaline amino acids, thiol and ester compounds were important for patulin adsorption. Additionally, besides hydrophobic interaction, electrostatic interaction also participated in patulin adsorption, which was enhanced with the increase in pH (4.0-6.0).
Šalomskienė, Joana; Abraitienė, Asta; Jonkuvienė, Dovilė; Mačionienė, Irena; Repečkienė, Jūratė
2015-07-01
The aim of the study was a detail evaluation of genetic diversity among the lactic acid bacteria (LAB) strains having an advantage of a starter culture in order to select genotypically diverse strains with enhanced antimicrobial effect on some harmfull and pathogenic microorganisms. Antimicrobial activity of LAB was performed by the agar well diffusion method and was examined against the reference strains and foodborne isolates of Bacillus cereus, Listeria monocytogenes, Escherichia coli, Staphylococcus aureus and Salmonella Typhimurium. Antifungal activity was tested against the foodborne isolates of Candida parapsilosis, Debaromyces hansenii, Kluyveromyces marxianus, Pichia guilliermondii, Yarowia lipolytica, Aspergillus brasiliensis, Aspergillus versicolor, Cladosporium herbarum, Penicillium chrysogenum and Scopulariopsis brevicaulis. A total 40 LAB strains representing Lactobacillus (23 strains), Lactococcus (13 strains) and Streptococcus spp. (4 strains) were characterised by repetitive sequence based polymerase chain reaction fingerprinting which generated highly discriminatory profiles, confirmed the identity and revealed high genotypic heterogeneity among the strains. Many of tested LAB demonstrated strong antimicrobial activity specialised against one or few indicator strains. Twelve LAB strains were superior in suppressing growth of the whole complex of pathogenic bacteria and fungi. These results demonstrated that separate taxonomic units offered different possibilities of selection for novel LAB strains could be used as starter cultures enhancing food preservation.
Identification and Characterization of Lactic Acid Bacteria in a Commercial Probiotic Culture
MENCONI, Anita; KALLAPURA, Gopala; LATORRE, Juan D.; MORGAN, Marion J.; PUMFORD, Neil R.; HARGIS, Billy M.; TELLEZ, Guillermo
2014-01-01
The aim of the present study was to describe the identification and characterization (physiological properties) of two strains of lactic acid bacteria (LAB 18 and 48) present in a commercial probiotic culture, FloraMax®-B11. Isolates were characterized morphologically, and identified biochemically. In addition, the MIDI System ID, the Biolog ID System, and 16S rRNA sequence analyses for identification of LAB 18 and LAB 48 strains were used to compare the identification results. Tolerance and resistance to acidic pH, high osmotic concentration of NaCl, and bile salts were tested in broth medium. In vitro assessment of antimicrobial activity against enteropathogenic bacteria and susceptibility to antibiotics were also tested. The results obtained in this study showed tolerance of LAB 18 and LAB 48 to pH 3.0, 6.5% NaCl and a high bile salt concentration (0.6%). Both strains evaluated showed in vitro antibacterial activity against Salmonella enterica serovar Enteritidis, Escherichia coli (O157:H7), and Campylobacter jejuni. These are important characteristics of lactic acid bacteria that should be evaluated when selecting strains to be used as probiotics. Antimicrobial activity of these effective isolates may contribute to efficacy, possibly by direct antimicrobial activity in vivo. PMID:24936379
Park, Mi Ri; Kim, Younghoon; Lee, Myung-Ki
2015-01-01
The present study was conducted to screen candidate probiotic strains for anti-inflammatory activity. Initially, a nitric oxide (NO) assay was used to test selected candidate probiotic strains for anti-inflammatory activity in cultures of the murine macrophage cell line, RAW 264.7. Then, the in vitro probiotic properties of the strains, including bile tolerance, acid resistance, and growth in skim milk media, were investigated. We also performed an in vitro hydrophobicity test and an intestinal adhesion assay using Caenorhabditis elegans as a surrogate in vivo model. From our screening, we obtained 4 probiotic candidate lactic acid bacteria (LAB) strains based on their anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated RAW 264.7 cell cultures and the results of the in vitro and in vivo probiotic property assessments. Molecular characterization using 16S rDNA sequencing analysis identified the 4 LAB strains as Lactobacillus plantarum. The selected L. plantarum strains (CAU1054, CAU1055, CAU1064, and CAU1106) were found to possess desirable in vitro and in vivo probiotic properties, and these strains are good candidates for further investigations in animal models and human clinical studies to elucidate the mechanisms underlying their anti-inflammatory activities. PMID:26761805
Identification of TLR2/TLR6 signalling lactic acid bacteria for supporting immune regulation.
Ren, Chengcheng; Zhang, Qiuxiang; de Haan, Bart J; Zhang, Hao; Faas, Marijke M; de Vos, Paul
2016-10-06
Although many lactic acid bacteria (LAB) influence the consumer's immune status it is not completely understood how this is established. Bacteria-host interactions between bacterial cell-wall components and toll-like receptors (TLRs) have been suggested to play an essential role. Here we investigated the interaction between LABs with reported health effects and TLRs. By using cell-lines expressing single or combination of TLRs, we show that LABs can signal via TLR-dependent and independent pathways. The strains only stimulated and did not inhibit TLRs. We found that several strains such as L. plantarum CCFM634, L. plantarum CCFM734, L. fermentum CCFM381, L. acidophilus CCFM137, and S. thermophilus CCFM218 stimulated TLR2/TLR6. TLR2/TLR6 is essential in immune regulatory processes and of interest for prevention of diseases. Specificity of the TLR2/TLR6 stimulation was confirmed with blocking antibodies. Immunomodulatory properties of LABs were also studied by assessing IL-10 and IL-6 secretion patterns in bacteria-stimulated THP1-derived macrophages, which confirmed species and strain specific effects of the LABs. With this study we provide novel insight in LAB specific host-microbe interactions. Our data demonstrates that interactions between pattern recognition receptors such as TLRs is species and strain specific and underpins the importance of selecting specific strains for promoting specific health effects.
Heterologous expression of enterocin AS-48 in several strains of lactic acid bacteria.
Fernández, M; Martínez-Bueno, M; Martín, M C; Valdivia, E; Maqueda, M
2007-05-01
Enterococcus faecalis produces a cationic and circular enterocin, AS-48, of 7149 Da, the genetic determinants of which are located within the pMB2 plasmid. We have compared enterocin AS-48 production by different enterococci species with that of other 'safe' lactic acid bacteris (LAB) (GRAS status) and looked into the subsequent application of this enterocin in food production. In an effort to exploit this system for the heterologous expression of enterocin AS-48, a number of vectors containing the as-48 cluster were constructed and used to transform several LAB strains (genera Enterococcus, Lactococcus and Lactobacillus) Heterologous production of enterocin AS-48 failed when bacteria other than those belonging to the genus Enterococcus were used as hosts, although expression of a partial level of resistance against AS-48 were always detected, ruling out the possibility of a lack of recognition of the enterococcal promoters. Our results reveal the special capacity of species from the genus Enterococcus to produce AS-48, an enterocin that requires a post-transcriptional modification to generate a circular peptide with a wide range of inhibitory activity against pathogenic and spoilage bacteria. Preliminary experiments in foodstuffs using nonvirulent enterococci with interesting functional properties reveal the possibility of a biotechnological application of these transformants.
Fujiwara, Daisuke; Inoue, Sayo; Wakabayashi, Hideyuki; Fujii, Toshio
2004-11-01
There is growing interest in the immune-stimulating effect and in particular, the anti-allergic effect, of lactic acid bacteria (LAB). However, no comprehensive studies have been done that compare the immune-stimulating potential of LAB strains. The in vitro immune-stimulating effects on Th1/Th2 balance of more than 100 LAB strains were compared in splenocytes from ovalbumin-sensitized Th2-polarized mice. The in vivo anti-allergic ability of strain KW3110 was studied in the Th2-polarized model by detecting serum IgE concentration, Th1/Th2 cytokine secretion from splenocytes, and the expression of co-stimulatory molecules on macrophages. In vitro studies from Th2-polarized splenocytes, using IL-12 as a Th1 parameter and IL-4 secretion as a Th2 parameter revealed a wide variety of IL-12-inducing and IL-4-repressing activities, depending on the strain of LAB, not depending on the species. However, evaluation of individual strains in vivo revealed that after exposure to Lactobacillus paracasei KW3110 strain, the serum IgE elevation elicited by repeated OVA injection of mice was strongly inhibited. Cytokine secretion from splenocytes 20 weeks after KW3110 administration showed increased IL-12 and decreased IL-4 expression. Both CD40 and B7-1 expression on macrophages was upregulated by administration of KW3110. Improving the consequences of the Th1/Th2 imbalance by administration of LAB was dependent upon the LAB strain rather than the LAB species. Oral KW3110 administration in the mouse allergy model directed the Th1/Th2 balance toward Th1 through the maturation of APCs and inhibition of serum IgE elevation.
Kaktcham, Pierre Marie; Temgoua, Jules-Bocamdé; Ngoufack Zambou, François; Diaz-Ruiz, Gloria; Wacher, Carmen; Pérez-Chabela, María de Lourdes
2017-02-01
The present study aimed to evaluate the bacterial load of water, Nile Tilapia and common Carp intestines from earthen ponds, isolate lactic acid bacteria (LAB) and assess their antimicrobial activity against fish spoilage and pathogenic bacteria. Following enumeration and isolation of microorganisms the antimicrobial activity of the LAB isolates was evaluated. Taxonomic identification of selected antagonistic LAB strains was assessed, followed by partial characterisation of their antimicrobial metabolites. Results showed that high counts (>4 log c.f.u ml -1 or 8 log c.f.u g -1 ) of total aerobic bacteria were recorded in pond waters and fish intestines. The microbiota were also found to be dominated by Salmonella spp., Vibrio spp., Staphylococcus spp. and Escherichia coli. LAB isolates (5.60%) exhibited potent direct and extracellular antimicrobial activity against the host-derived and non host-derived spoilage and pathogenic bacteria. These antagonistic isolates were identified and Lactococcus lactis subsp. lactis was found as the predominant (42.85%) specie. The strains displayed the ability to produce lactic, acetic, butyric, propionic and valeric acids. Bacteriocin-like inhibitory substances with activity against Gram-positive and Gram-negative (Vibrio spp. and Pseudomonas aeruginosa) bacteria were produced by three L. lactis subsp. lactis strains. In this study, the LAB from the microbiota of fish and pond water showed potent antimicrobial activity against fish spoilage or pathogenic bacteria from the same host or ecological niche. The studied Cameroonian aquatic niche is an ideal source of antagonistic LAB that could be appropriate as new fish biopreservatives or disease control agents in aquaculture under tropical conditions in particular or worldwide in general.
Smitinont, T; Tansakul, C; Tanasupawat, S; Keeratipibul, S; Navarini, L; Bosco, M; Cescutti, P
1999-10-15
Lactic Acid Bacteria (LAB) isolated from various traditional Thai fermented foods were screened for exopolysaccharides (EPS) production. From 104 isolates, two rod-shaped and five coccal-shaped LAB were able to produce EPS from sucrose on solid media. However, only the cocci were capable of producing EPS in liquid media and these were identified as Pediococcus pentosaceus. Pediococcus pentosaceus strains AP-1 and AP-3 produced EPS in high yield. In liquid media containing sucrose as carbon source, the amount of EPS produced by AP-1 and AP-3 strains was 6.0 and 2.5 g/L, respectively. The isolated and purified EPSs were chemically characterized. On the basis of sugar composition, methylation analysis and nuclear magnetic resonance spectroscopy, both the EPSs were shown to belong to the same dextran class. In particular, both EPSs differed from linear dextran by branching through 3,6-di-Osubstituted alpha-D-glucopyranosyl residues. The EPS from P. pentosaceus AP-3 was characterized by a relatively higher degree of branching and by a higher molecular weight than that from P. pentosaceus AP-1.
Fan, Qin; Liu, Shuliang; Li, Juan; Huang, Tingting
2012-05-01
To analyze the antimicrobial susceptibility of lactic acid bacteria (LAB) from yogurt, and to provide references for evaluating the safety of LAB and screening safe strains. The sensitivity of 43 LAB strains, including 14 strains of Streptococcus thermophilus, 12 strains of Lactobacillus acidophilus, 9 strains of Lactobacillus bulgaricus and 8 strains of Bifidobacterium, to 22 antibiotics were tested by agar plate dilution method. All 43 LAB strains were resistant to trimethoprim, nalidixic acid, ciprofloxacin, lomefloxacin, danofloxacin and polymyxin E. Their resistances to kanamycin, tetracycline, clindamycin, doxycycline and cephalothin were varied. The sensitivity to other antibiotics were sensitive or moderate. All isolates were multidrug-resistant. The antimicrobial resistance of tested LAB strains was comparatively serious, and continuously monitoring their antimicrobial resistance and evaluating their safety should be strengthened.
[Characteristics of natural strains of naphthalene-utilizing bacteria of the genus Pseudomonas].
Levchuk, A A; Vasilenko, S L; Bulyga, I M; Titok, M A; Thomas, K M
2005-01-01
Sixty-three strains of bacteria capable of utilizing naphthalene as the sole source of carbon and energy were isolated from 137 samples of soil taken in different sites in Belarus. All isolated bacteria contained extrachromosomal genetic elements of 45 to 150 kb in length. It was found that bacteria of 31 strains contained the IncP-9 incompatibility group plasmids, bacteria of one strain carried a plasmid containing replicons IncP-9 and IncP-7, and bacteria of 31 strains contained unidentified plasmids. Primary identification showed that the hosts of plasmids of naphthalene biodegradation are fluorescent bacteria of the genus Pseudomonas (P. putida and P. aeruginosa; a total of 47 strains) and unidentified nonfluorescent microorganisms (a total of 16 strains). In addition to the ability to utilize naphthalene, some strains exhibited the ability to stimulate the growth and development of the root system of Secale cereale.
Ndlovu, B; Schoeman, H; Franz, C M A P; du Toit, M
2015-04-01
To screen and identify wine-isolated LAB strains for bacteriocin production, and to identify and characterize bacteriocins. One hundred and fifty-five LAB strains isolated from South African red wines undergoing spontaneous malolactic fermentation were screened for bacteriocin production. Eight isolates were identified to be bacteriocin producers and were identified as Enterococcus faecium. All eight isolates had the same phenotypic and genotypic profiles. The peptides were preliminarily identified as enterocin P using mass spectrometry and further confirmed by PCR-amplifying enterocin P gene. The enterocin activity was inhibited by α-Chymotrypsin, papain and proteinase K treatments. It was heat stable at 37, 60, 80 and 100°C and showed activity over a broad pH range of 2-10. The production of the enterocin followed that of primary metabolite kinetics and, it showed bactericidal effect to some wine spoilage LAB strains. Our study identified the presence of the enterocin-producing Enterococcus in wine. The enterocin was heat stable; with broad pH range and bactericidal effects to sensitive strains. This is one of very few studies that isolated Enterococcus species from wine. It is, however, the first to report presence of bacteriocin-producing Enterococcus in wine fermentation. © 2015 The Society for Applied Microbiology.
Ignatova, Tseteslava; Iliev, Ilia; Kirilov, Nikolai; Vassileva, Tonka; Dalgalarrondo, Michèle; Haertlé, Thomas; Chobert, Jean-Marc; Ivanova, Iskra
2009-10-28
Eighteen lactic acid bacteria (LAB) strains isolated from dairy products, all identified as Lactobacillus delbrueckii subsp. bulgaricus, were tested for their ability to grow on three different oligosaccharides: fructo-oligosaccharides (FOS), gluco-oligosaccharides (GOS) and galacto-oligosaccharides (GalOS). The growth of LAB on different oligosaccharides was very different. Study of the antimicrobial activities of these LAB indicated that the system of uptake of unusual sugars influenced in a specific way the production of antimicrobial substances (bacteriocins) specific against gram-negative bacteria. The added oligosaccharides induced LAB to form end-products of a typical mixed acid fermentation. The utilization of different types of oligosaccharides may help to explain the ability of Lactobacillus strains to compete with other bacteria in the ecosystem of the human gastro-intestinal tract.
Zoumpopoulou, Georgia; Pepelassi, Eudoxie; Papaioannou, William; Georgalaki, Marina; Maragkoudakis, Petros A.; Tarantilis, Petros A.; Polissiou, Moschos; Tsakalidou, Effie; Papadimitriou, Konstantinos
2013-01-01
In the present study we investigated the incidence of bacteriocins produced by 236 lactic acid bacteria (LAB) food isolates against pathogenic or opportunistic pathogenic oral bacteria. This set of LAB contained several strains (≥17%) producing bacteriocins active against food-related bacteria. Interestingly only Streptococcus macedonicus ACA-DC 198 was able to inhibit the growth of Streptococcus oralis, Streptococcus sanguinis and Streptococcus gordonii, while Lactobacillus fermentum ACA-DC 179 and Lactobacillus plantarun ACA-DC 269 produced bacteriocins solely against Streptococcus oralis. Thus, the percentage of strains that were found to produce bacteriocins against oral bacteria was ~1.3%. The rarity of bacteriocins active against oral LAB pathogens produced by food-related LAB was unexpected given their close phylogenetic relationship. Nevertheless, when tested in inhibition assays, the potency of the bacteriocin(s) of S. macedonicus ACA-DC 198 against the three oral streptococci was high. Fourier-transform infrared spectroscopy combined with principal component analysis revealed that exposure of the target cells to the antimicrobial compounds caused major alterations of key cellular constituents. Our findings indicate that bacteriocins produced by food-related LAB against oral LAB may be rare, but deserve further investigation since, when discovered, they can be effective antimicrobials. PMID:23443163
2009-01-01
Background The Lactic Acid Bacteria (LAB) are important components of the healthy gut flora and have been used extensively as probiotics. Understanding the cultivable diversity of LAB before and after probiotic administration, and being able to track the fate of administered probiotic isolates during feeding are important parameters to consider in the design of clinical trials to assess probiotic efficacy. Several methods may be used to identify bacteria at the strain level, however, PCR-based methods such as Random Amplified Polymorphic DNA (RAPD) are particularly suited to rapid analysis. We examined the cultivable diversity of LAB in the human gut before and after feeding with two Lactobacillus strains, and also tracked the fate of these two administered strains using a RAPD technique. Results A RAPD typing scheme was developed to genetically type LAB isolates from a wide range of species, and optimised for direct application to bacterial colony growth. A high-throughput strategy for fingerprinting the cultivable diversity of human faeces was developed and used to determine: (i) the initial cultivable LAB strain diversity in the human gut, and (ii) the fate of two Lactobacillus strains (Lactobacillus salivarius NCIMB 30211 and Lactobacillus acidophilus NCIMB 30156) contained within a capsule that was administered in a small-scale human feeding study. The L. salivarius strain was not cultivated from the faeces of any of the 12 volunteers prior to capsule administration, but appeared post-feeding in four. Strains matching the L. acidophilus NCIMB 30156 feeding strain were found in the faeces of three volunteers prior to consumption; after taking the Lactobacillus capsule, 10 of the 12 volunteers were culture positive for this strain. The appearance of both Lactobacillus strains during capsule consumption was statistically significant (p < 0.05). Conclusion We have shown that genetic strain typing of the cultivable human gut microbiota can be evaluated using a high
Tamang, Jyoti Prakash; Tamang, Buddhiman; Schillinger, Ulrich; Guigas, Claudia; Holzapfel, Wilhelm H
2009-09-30
A total of 94 strains of Lactic acid bacteria (LAB), previously isolated from ethnic fermented vegetables and tender bamboo shoots of the Himalayas, were screened for functional properties such as acidification capacity, enzymatic activities, degradation of antinutritive factors and oligosaccharides, production of biogenic amines, hydrophobicity and adherence to mucus secreting HT29 MTX cells. Strong acidification and coagulation activities of LAB strains were recorded. Most of the LAB strains showed antimicrobial activities against the used indicator strains; however, only Lb. plantarum IB2 (BFE 948) isolated from inziangsang, a fermented leafy vegetable product, produced a bacteriocin against Staphylococcus aureus S1. LAB strains showed enzymatic activities and also degraded oligosaccharides. Almost all the strains of LAB were non-producers of biogenic amines except few strains. Some strains of Lb. plantarum showed more than 70% hydrophobicity. Adherence to the mucus secreting HT29 MTX cells was also shown by seven strains indicating their probiotic nature.
Dewan, Sailendra; Tamang, Jyoti Prakash
2007-10-01
Ethnic people of the Himalayan regions of India, Nepal, Bhutan and China consume a variety of indigenous fermented milk products made from cows milk as well as yaks milk. These lesser-known ethnic fermented foods are dahi, mohi, chhurpi, somar, philu and shyow. The population of lactic acid bacteria (LAB) ranged from 10(7) to 10(8) cfu/g in these Himalayan milk products. A total of 128 isolates of LAB were isolated from 58 samples of ethnic fermented milk products collected from different places of India, Nepal and Bhutan. Based on phenotypic characterization including API sugar test, the dominant lactic acid bacteria were identified as Lactobacillus bifermentans, Lactobacillus paracasei subsp. pseudoplantarum, Lactobacillus kefir, Lactobacillus hilgardii, Lactobacillus alimentarius, Lactobacillus paracasei subsp. paracasei, Lactobacillus plantarum, Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris and Enterococcus faecium. LAB produced a wide spectrum of enzymes and showed high galactosidase, leucine-arylamidase and phosphatase activities. They showed antagonistic properties against selected Gram-negative bacteria. None of the strains produced bacteriocin and biogenic amines under the test conditions used. Most strains of LAB coagulated skim milk with a moderate drop in pH. Some strains of LAB showed a high degree of hydrophobicity, suggesting these strains may have useful adhesive potential. This paper is the first report on functional lactic acid bacterial composition in some lesser-known ethnic fermented milk products of the Himalayas.
Engineering lactic acid bacteria for increased industrial functionality.
Bron, Peter A; Kleerebezem, Michiel
2011-01-01
Based on their spoilage-preventing and flavor-contributing characteristics, lactic acid bacteria (LAB) are employed as starter cultures for the fermentation of foods and feeds. In addition, several specific LAB strains are marketed on basis of their beneficial effects on the consumer's health, representing an explosively growing market for the products containing these so-called probiotics. Due to this extensive industrial use there is a strong interest in unraveling the molecular mechanisms involved in industrial robustness, cognate stress resistance, and health-promoting phenotypes of these LAB that may vary drastically between different starter and probiotic strains currently marketed. This review describes some of the post-genomic tools developed, as well as their employment for the identification of bacterial effector molecules involved in the aforementioned industrially relevant phenotypes. Furthermore, it addresses possible strategies to exploit such knowledge into the rational design of LAB strains with increased industrial functionality.
[Composition diversity of lactic acid bacteria (LAB) community Al2 used for alfalfa silage].
Wang, Xiao-Fen; Gao, Li-Juan; Yang, Hong-Yan; Wang, Wei-Dong; Cui, Zong-Jun
2006-10-01
Alfalfa is the most important forage grass that is difficult to ensile for good quality. Using silage inoculants are the important way for preservation of alfalfa silage. Through continuous restricted subcultivation, a lactic acid bacteria (LAB) community Al2 was selected from well-fermented alfalfa silage. Plate isolation and Denaturing Gradient Gel Electrophoresis (DGGE), construction of 16S rDNA clone library were used to identify the composition diversity of Al2 community, with 7 strains detected, and they were all belonged to Lactobacillus. The composition ratios of the 7 strains were 55.21%, 19.79%, 14.58%, 3.13%, 3.13%, 3.13%, 1.03% according to 16S rDNA clone library. Al2-1i, Al2-2i, Al2-3i, corresponding to L. plantarum (99.9%), L. kimchii (99.4%), L. farciminis (100%) were detected by plate isolation. Among 3 isolates, Al2-1i had the highest ability of dropping pH and producing lactic acid, and the amount of lactic acid was reach to 18g/L at 24h cultivated in MRS media. The ability of dropping pH and producing lactic acid of Al2-3i was the lowest. From DGGE profiles, the dominant strains in Al2 community were L. plantarum and L. kimchii. L. plantarum was detected during the whole process, and L. kimchii was detected in the later phase.
Evaluation of Petrifilm Lactic Acid Bacteria Plates for Counting Lactic Acid Bacteria in Food.
Kanagawa, Satomi; Ohshima, Chihiro; Takahashi, Hajime; Burenqiqige; Kikuchi, Misato; Sato, Fumina; Nakamura, Ayaka; Mohamed, Shimaa M; Kuda, Takashi; Kimura, Bon
2018-06-01
Although lactic acid bacteria (LAB) are used widely as starter cultures in the production of fermented foods, they are also responsible for food decay and deterioration. The undesirable growth of LAB in food causes spoilage, discoloration, and slime formation. Because of these adverse effects, food companies test for the presence of LAB in production areas and processed foods and consistently monitor the behavior of these bacteria. The 3M Petrifilm LAB Count Plates have recently been launched as a time-saving and simple-to-use plate designed for detecting and quantifying LAB. This study compares the abilities of Petrifilm LAB Count Plates and the de Man Rogosa Sharpe (MRS) agar medium to determine the LAB count in a variety of foods and swab samples collected from a food production area. Bacterial strains isolated from Petrifilm LAB Count Plates were identified by 16S rDNA sequence analysis to confirm the specificity of these plates for LAB. The results showed no significant difference in bacterial counts measured by using Petrifilm LAB Count Plates and MRS medium. Furthermore, all colonies growing on Petrifilm LAB Count Plates were confirmed to be LAB, while yeast colonies also formed in MRS medium. Petrifilm LAB Count Plates eliminated the plate preparation and plate inoculation steps, and the cultures could be started as soon as a diluted food sample was available. Food companies are required to establish quality controls and perform tests to check the quality of food products; the use of Petrifilm LAB Count Plates can simplify this testing process for food companies.
Favaro, Lorenzo; Todorov, Svetoslav Dimitrov
2017-12-01
Over the last decades, much research has focused on lactic acid bacteria (LAB) bacteriocins because of their potential as biopreservatives and their action against the growth of spoilage microbes. Meat and fermented meat products are prone to microbial contamination, causing health risks, as well as economic losses in the meat industry. The use of bacteriocin-producing LAB starter or protective cultures is suitable for fermented meats. However, although bacteriocins can be produced during meat processing, their levels are usually much lower than those achieved during in vitro fermentations under optimal environmental conditions. Thus, the direct addition of a bacteriocin food additive would be desirable. Moreover, safety and technological characteristics of the bacteriocinogenic LAB must be considered before their widespread applications. This review describes the perspectives and challenges toward the complete disclosure of new bacteriocins as effective preservatives in the production of safe and "healthy" fermented meat products.
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
R, Jini; HC, Swapna; Rai, Amit Kumar; R, Vrinda; PM, Halami; NM, Sachindra; N, Bhaskar
2011-01-01
Proteolytic and/or lipolytic lactic acid bacteria (LAB) were isolated from visceral wastes of different fresh water fishes. LAB count was found to be highest in case of visceral wastes of Mrigal (5.88 log cfu/g) and lowest in that of tilapia (4.22 log cfu/g). Morphological, biochemical and molecular characterization of the selected LAB isolates were carried out. Two isolates FJ1 (E. faecalis NCIM5367) and LP3 (P. acidilactici NCIM5368) showed both proteolytic and lipolytic properties. All the six native isolates selected for characterization showed antagonistic properties against several human pathogens. All the native isolates were sensitive to antibiotics cephalothin and clindamycin; and, resistant to cotrimoxazole and vancomycin. Considering individually, P. acidilactici FM37, P. acidilactici MW2 and E. faecalis FD3 were sensitive to erythromycin. The two strains FJ1 (E. faecalis NCIM 5367) and LP3 (P. acidilactici NCIM 5368) that had both proteolytic and lipolytic properties have the potential for application in fermentative recovery of lipids and proteins from fish processing wastes. PMID:24031786
Lactic acid bacteria as oral delivery systems for biomolecules.
Berlec, A; Ravnikar, M; Strukelj, B
2012-11-01
Lactic acid bacteria (LAB) have become increasingly studied over the last two decades as potential delivery systems for various biological molecules to the gastrointestinal tract. This article presents an overview of characteristics of LAB as delivery systems and of the applications which have already been developed. The majority of LAB strains are able to survive the intestinal passage and some are also able to persist and colonize the intestine. Several strains were in fact described as members of the human commensal flora. They can interact with their host and are able to deliver large molecular weight biomolecules across the epithelium via M-cells or dendritic cells. The most widely applied LAB species has been Lactococcus lactis; however species from genus Lactobacillus are gaining popularity and the first examples from genus Bifidobacterium are starting to emerge. Bacteria are mostly applied live and enable continuous delivery of the biomolecules. However, killed bacteria (e.g. gram-positive enhancer matrix), with bound biomolecules or as adjuvants, are also being developed. The techniques for genetic modification of LAB are well known. This review focuses on the delivery of recombinant proteins and DNA, which can cause either local or systemic effects. We divide recombinant proteins into antigens and therapeutic proteins. Delivery of antigens for the purpose of vaccination represents the most abundant application with numerous successful demonstrations of the efficacy on the animal model. Therapeutic proteins have mostly been developed for the treatment of the inflammatory bowel disease, by the delivery of anti-inflammatory cytokines, or downregulation of proinflammatory cytokines. Delivery of allergens for the modulation of allergic disorders represents the second most popular application of therapeutic proteins. The delivery of DNA by LAB was demonstrated and offers exciting opportunities, especially as a vaccine. New discoveries may eventually lead to the
Singhvi, Mamata; Zendo, Takeshi; Sonomoto, Kenji
2018-05-26
Lactic acid (LA) is an important platform chemical due to its significant applications in various fields and its use as a monomer for the production of biodegradable poly(lactic acid) (PLA). Free LA production is required to get rid of CaSO 4 , a waste material produced during fermentation at neutral pH which will lead to easy purification of LA required for the production of biodegradable PLA. Additionally, there is no need to use corrosive acids to release free LA from the calcium lactate produced during neutral fermentation. To date, several attempts have been made to improve the acid tolerance of lactic acid bacteria (LAB) by using both genome-shuffling approaches and rational design based on known mechanisms of LA tolerance and gene deletion in yeast strains. However, the lack of knowledge and the complexity of acid-tolerance mechanisms have made it challenging to generate LA-tolerant strains by simply modifying few target genes. Currently, adaptive evolution has proven an efficient strategy to improve the LA tolerance of individual/engineered strains. The main objectives of this article are to summarize the conventional biotechnological LA fermentation processes to date, assess their overall economic and environmental cost, and to introduce modern LA fermentation strategies for free LA production. In this review, we provide a broad overview of free LA fermentation processes using robust LAB that can ferment in acidic environments, the obstacles to these processes and their possible solutions, and the impact on future development of free LA fermentation processes commercially.
Kondo, Ayaka; Asami, Kyoko; Suda, Yoshihito; Shimoyamada, Makoto; Kanauchi, Makoto
2016-06-01
Recently, many scholars have reported lactic acid bacteria (LAB) functions, such as anticancer activity and anti-inflammatory activity for intestines. To decrease inflammatory substances such as endotoxins, LAB consumed safely with meals were isolated from food and food ingredients. First, LAB were isolated as 168 strains of bacillus LAB (49 strain) and coccus LAB (119 strains) from food ingredients and fermented foods such as rice, rice bran, malt, grains, miso soy paste, and some pickles. Their LAB (168 strains) were cultivated in medium containing endotoxin from Escherichia coli O18 LPS at 15 and 30 °C for 64 h to identify endotoxin-eliminating LAB. Consequently, the AK-23 strain was screened as an endotoxin-eliminating LAB strain. The strain decreased endotoxin in YP medium without sugar at 30 °C for 64 h until 9% of endotoxin. The strain was identified as Pediococcus pentosaceus according to morphological characteristics such as its cell shape, physiological characteristics related to its fermentation type, assimilation of sugars, pH tolerance, optimum growth temperature, and molecular biological characteristics as its homology to 16S rRNA. To investigate the location of the endotoxin-eliminating substance, 4 fractions were separated from AK-23 cells as extracellular, cell wall digestion, cytoplasm, and cell membrane fractions. The endotoxin-decreasing substance, located on a cell wall, was identified as a 217 kDa protein. © 2016 Institute of Food Technologists®
Valerio, Francesca; Favilla, Mara; De Bellis, Palmira; Sisto, Angelo; de Candia, Silvia; Lavermicocca, Paola
2009-09-01
Thirty samples of Italian durum wheat semolina and whole durum wheat semolina, generally used for the production of Southern Italy's traditional breads, were subjected to microbiological analysis in order to explore their lactic acid bacteria (LAB) diversity and to find strains with antifungal activity. A total of 125 presumptive LAB isolates (Gram-positive and catalase-negative) were characterized by repetitive extragenic palindromic-PCR (REP-PCR) and sequence analysis of the 16S rRNA gene, leading to the identification of the following species: Weissella confusa, Weissella cibaria, Leuconostoc citreum, Leuconostoc mesenteroides, Lactococcus lactis, Lactobacillus rossiae and Lactobacillus plantarum. The REP-PCR results delineated 17 different patterns whose cluster analysis clearly differentiated W. cibaria from W. confusa isolates. Seventeen strains, each characterized by a different REP-PCR pattern, were screened for their antifungal properties. They were grown in a flour-based medium, comparable to a real food system, and the resulting fermentation products (FPs) were tested against fungal species generally contaminating bakery products, Aspergillus niger, Penicillium roqueforti and Endomyces fibuliger. The results of the study indicated a strong inhibitory activity - comparable to that obtained with the common preservative calcium propionate (0.3% w/v) - of ten LAB strains against the most widespread contaminant of bakery products, P. roqueforti. The screening also highlighted the unexplored antifungal activity of L. citreum, L. rossiae and W. cibaria (1 strain), which inhibited all fungal strains to the same or a higher extent compared with calcium propionate. The fermentation products of these three strains were characterized by low pH values, and a high content of lactic and acetic acids.
Identification of lactic acid bacteria from chili bo, a Malaysian food ingredient.
Leisner, J J; Pot, B; Christensen, H; Rusul, G; Olsen, J E; Wee, B W; Muhamad, K; Ghazali, H M
1999-02-01
Ninety-two strains of lactic acid bacteria (LAB) were isolated from a Malaysian food ingredient, chili bo, stored for up to 25 days at 28 degreesC with no benzoic acid (product A) or with 7,000 mg of benzoic acid kg-1 (product B). The strains were divided into eight groups by traditional phenotypic tests. A total of 43 strains were selected for comparison of their sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) whole-cell protein patterns with a SDS-PAGE database of LAB. Isolates from product A were identified as Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus farciminis, Pediococcus acidilactici, Enterococcus faecalis, and Weissella confusa. Five strains belonging to clusters which could not be allocated to existing species by SDS-PAGE were further identified by 16S rRNA sequence comparison. One strain was distantly related to the Lactobacillus casei/Pediococcus group. Two strains were related to Weissella at the genus or species level. Two other strains did not belong to any previously described 16S rRNA group of LAB and occupied an intermediate position between the L. casei/Pediococcus group and the Weissella group and species of Carnobacterium. The latter two strains belong to the cluster of LAB that predominated in product B. The incidence of new species and subspecies of LAB in chili bo indicate the high probability of isolation of new LAB from certain Southeast Asian foods. None of the isolates exhibited bacteriocin activity against L. plantarum ATCC 14917 and LMG 17682.
Characterization and application of lactic acid bacteria for tropical silage preparation.
Pholsen, Suradej; Khota, Waroon; Pang, Huili; Higgs, David; Cai, Yimin
2016-10-01
Strains TH 14, TH 21 and TH 64 were isolated from tropical silages, namely corn stover, sugar cane top and rice straw, respectively, prepared in Thailand. These strains were selected by low pH growth range and high lactic acid-producing ability, similar to some commercial inoculants. Based on the analysis of 16S ribosomal RNA gene sequence and DNA-DNA relatedness, strain TH 14 was identified as Lactobacillus casei, and strains TH 21 and TH 64 were identified as L. plantarum. Strains TH 14, TH 21, TH 64 and two commercial inoculants, CH (L. plantarum) and SN (L. rhamnosus), were used as additives to fresh and wilted purple Guinea and sorghum silages prepared using a small-scale fermentation method. The number of epiphytic lactic acid bacteria (LAB) in the forages before ensilage was relatively low but the numbers of coliform and aerobic bacteria were higher. Sorghum silages at 30 days of fermentation were all well preserved with low pH (3.56) and high lactic acid production (72.86 g/kg dry matter). Purple Guinea silage inoculated with LAB exhibited reduced count levels of aerobic and coliform bacteria, lower pH, butyric acid and ammonia nitrogen and increased lactic acid concentration, compared with the control. Strain TH 14 more effectively improved lactic acid production compared with inoculants and other strains. © 2016 Japanese Society of Animal Science. © 2016 Japanese Society of Animal Science.
Vogelmann, Stephanie A; Seitter, Michael; Singer, Ulrike; Brandt, Markus J; Hertel, Christian
2009-04-15
The adaptability of lactic acid bacteria (LAB) and yeasts to sourdoughs prepared from cereals, pseudocereals and cassava was investigated using PCR-DGGE and bacteriological culture combined with rRNA gene sequence analysis. Sourdoughs were prepared either from flours of the cereals wheat, rye, oat, barley, rice, maize, and millet, or from the pseudocereals amaranth, quinoa, and buckwheat, or from cassava, using a starter consisting of various species of LAB and yeasts. Doughs were propagated until a stable microbiota was established. The dominant LAB and yeast species were Lactobacillus fermentum, Lactobacillus helveticus, Lactobacillus paralimentarius, Lactobacillus plantarum, Lactobacillus pontis, Lactobacillus spicheri, Issatchenkia orientalis and Saccharomyces cerevisiae. The proportion of the species within the microbiota varied. L. paralimentarius dominated in the pseudocereal sourdoughs, L. fermentum, L. plantarum and L. spicheri in the cassava sourdough, and L. fermentum, L. helveticus and L. pontis in the cereal sourdoughs. S. cerevisiae constituted the dominating yeast, except for quinoa sourdough, where I. orientalis also reached similar counts, and buckwheat and oat sourdoughs, where no yeasts could be detected. To assess the usefulness of competitive LAB and yeasts as starters, the fermentations were repeated using flours from rice, maize, millet and the pseudocereals, and by starting the dough fermentation with selected dominant strains. At the end of fermentation, most of starter strains belonged to the dominating microbiota. For the rice, millet and quinoa sourdoughs the species composition was similar to that of the prior fermentation, whereas in the other sourdoughs, the composition differed.
Gómez, Natacha C.; Ramiro, Juan M. P.; Quecan, Beatriz X. V.; de Melo Franco, Bernadette D. G.
2016-01-01
Use of probiotic biofilms can be an alternative approach for reducing the formation of pathogenic biofilms in food industries. The aims of this study were (i) to evaluate the probiotic properties of bacteriocinogenic (Lactococcus lactis VB69, L. lactis VB94, Lactobacillus sakei MBSa1, and Lactobacillus curvatus MBSa3) and non-bacteriocinogenic (L. lactis 368, Lactobacillus helveticus 354, Lactobacillus casei 40, and Weissela viridescens 113) lactic acid bacteria (LAB) isolated from Brazilian’s foods and (ii) to develop protective biofilms with these strains and test them for exclusion of Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Typhimurium. LAB were tested for survival in acid and bile salt conditions, surface properties, biosurfactant production, β-galactosidase and gelatinase activity, antibiotic resistance and presence of virulence genes. Most strains survived exposure to pH 2 and 4% bile salts. The highest percentages of auto-aggregation were obtained after 24 h of incubation. Sixty-seven percentage auto-aggregation value was observed in W. viridescens 113 and Lactobacillus curvatus MBSa3 exhibited the highest co-aggregation (69% with Listeria monocytogenes and 74.6% with E. coli O157:H7), while the lowest co-aggregation was exhibited by W. viridescens 113 (53.4% with Listeria monocytogenes and 38% with E. coli O157:H7). Tests for hemolytic activity, bacterial cell adherence with xylene, and drop collapse confirmed the biosurfactant-producing ability of most strains. Only one strain (L. lactis 368) produced β-galactosidase. All strains were negative for virulence genes cob, ccf, cylLL, cylLs, cyllM, cylB, cylA and efaAfs and gelatinase production. The antibiotic susceptibility tests indicated that the MIC for ciprofloxacin, clindamycin, gentamicin, kanamycin, and streptomycin did not exceed the epidemiological cut-off suggested by the European Food Safety Authority. Some strains were resistant to one or more antibiotics and
Stress Physiology of Lactic Acid Bacteria
Papadimitriou, Konstantinos; Alegría, Ángel; Bron, Peter A.; de Angelis, Maria; Gobbetti, Marco; Kleerebezem, Michiel; Lemos, José A.; Linares, Daniel M.; Ross, Paul; Stanton, Catherine; Turroni, Francesca; van Sinderen, Douwe; Varmanen, Pekka; Ventura, Marco; Zúñiga, Manuel; Tsakalidou, Effie
2016-01-01
SUMMARY Lactic acid bacteria (LAB) are important starter, commensal, or pathogenic microorganisms. The stress physiology of LAB has been studied in depth for over 2 decades, fueled mostly by the technological implications of LAB robustness in the food industry. Survival of probiotic LAB in the host and the potential relatedness of LAB virulence to their stress resilience have intensified interest in the field. Thus, a wealth of information concerning stress responses exists today for strains as diverse as starter (e.g., Lactococcus lactis), probiotic (e.g., several Lactobacillus spp.), and pathogenic (e.g., Enterococcus and Streptococcus spp.) LAB. Here we present the state of the art for LAB stress behavior. We describe the multitude of stresses that LAB are confronted with, and we present the experimental context used to study the stress responses of LAB, focusing on adaptation, habituation, and cross-protection as well as on self-induced multistress resistance in stationary phase, biofilms, and dormancy. We also consider stress responses at the population and single-cell levels. Subsequently, we concentrate on the stress defense mechanisms that have been reported to date, grouping them according to their direct participation in preserving cell energy, defending macromolecules, and protecting the cell envelope. Stress-induced responses of probiotic LAB and commensal/pathogenic LAB are highlighted separately due to the complexity of the peculiar multistress conditions to which these bacteria are subjected in their hosts. Induction of prophages under environmental stresses is then discussed. Finally, we present systems-based strategies to characterize the “stressome” of LAB and to engineer new food-related and probiotic LAB with improved stress tolerance. PMID:27466284
Stress Physiology of Lactic Acid Bacteria.
Papadimitriou, Konstantinos; Alegría, Ángel; Bron, Peter A; de Angelis, Maria; Gobbetti, Marco; Kleerebezem, Michiel; Lemos, José A; Linares, Daniel M; Ross, Paul; Stanton, Catherine; Turroni, Francesca; van Sinderen, Douwe; Varmanen, Pekka; Ventura, Marco; Zúñiga, Manuel; Tsakalidou, Effie; Kok, Jan
2016-09-01
Lactic acid bacteria (LAB) are important starter, commensal, or pathogenic microorganisms. The stress physiology of LAB has been studied in depth for over 2 decades, fueled mostly by the technological implications of LAB robustness in the food industry. Survival of probiotic LAB in the host and the potential relatedness of LAB virulence to their stress resilience have intensified interest in the field. Thus, a wealth of information concerning stress responses exists today for strains as diverse as starter (e.g., Lactococcus lactis), probiotic (e.g., several Lactobacillus spp.), and pathogenic (e.g., Enterococcus and Streptococcus spp.) LAB. Here we present the state of the art for LAB stress behavior. We describe the multitude of stresses that LAB are confronted with, and we present the experimental context used to study the stress responses of LAB, focusing on adaptation, habituation, and cross-protection as well as on self-induced multistress resistance in stationary phase, biofilms, and dormancy. We also consider stress responses at the population and single-cell levels. Subsequently, we concentrate on the stress defense mechanisms that have been reported to date, grouping them according to their direct participation in preserving cell energy, defending macromolecules, and protecting the cell envelope. Stress-induced responses of probiotic LAB and commensal/pathogenic LAB are highlighted separately due to the complexity of the peculiar multistress conditions to which these bacteria are subjected in their hosts. Induction of prophages under environmental stresses is then discussed. Finally, we present systems-based strategies to characterize the "stressome" of LAB and to engineer new food-related and probiotic LAB with improved stress tolerance. Copyright © 2016, American Society for Microbiology. All Rights Reserved.
Towards lactic acid bacteria-based biorefineries.
Mazzoli, Roberto; Bosco, Francesca; Mizrahi, Itzhak; Bayer, Edward A; Pessione, Enrica
2014-11-15
Lactic acid bacteria (LAB) have long been used in industrial applications mainly as starters for food fermentation or as biocontrol agents or as probiotics. However, LAB possess several characteristics that render them among the most promising candidates for use in future biorefineries in converting plant-derived biomass-either from dedicated crops or from municipal/industrial solid wastes-into biofuels and high value-added products. Lactic acid, their main fermentation product, is an attractive building block extensively used by the chemical industry, owing to the potential for production of polylactides as biodegradable and biocompatible plastic alternative to polymers derived from petrochemicals. LA is but one of many high-value compounds which can be produced by LAB fermentation, which also include biofuels such as ethanol and butanol, biodegradable plastic polymers, exopolysaccharides, antimicrobial agents, health-promoting substances and nutraceuticals. Furthermore, several LAB strains have ascertained probiotic properties, and their biomass can be considered a high-value product. The present contribution aims to provide an extensive overview of the main industrial applications of LAB and future perspectives concerning their utilization in biorefineries. Strategies will be described in detail for developing LAB strains with broader substrate metabolic capacity for fermentation of cheaper biomass. Copyright © 2014 Elsevier Inc. All rights reserved.
Lactic acid bacteria in Hamei and Marcha of North East India.
Tamang, J P; Dewan, S; Tamang, B; Rai, A; Schillinger, U; Holzapfel, W H
2007-06-01
Hamei and Marcha are mixed dough inocula used as starters for preparation of various indigenous alcoholic beverages in Manipur and Sikkim in India, respectively. These starters are traditionally prepared from rice with wild herbs and spices. Samples of Hamei and Marcha, collected from Manipur and Sikkim, respectively, were analysed for lactic acid bacterial composition. The population of lactic acid bacteria (LAB) was 6.9 and 7.1 Log cfu/g in Hamei and Marcha, respectively. On the basis of phenotypic and genotypic characters, LAB strains isolated from Hamei and Marcha were identified as Pediococcus pentosaceus, Lactobacillus plantarum and Lactobacillus brevis. Technological properties of LAB such as antimicrobial properties, effect on acidification, ability to produce biogenic amines and ethanol, degree of hydrophobicity and enzymatic activities were also performed. Pediococcus pentosaceus HS: B1, isolated from Hamei, was found to produce bacteriocin. None of the strains produced biogenic amines. LAB strains showed a strong acidifying ability and they also produced a wide spectrum of enzymes.
Genomics of lactic acid bacteria: Current status and potential applications.
Wu, Chongde; Huang, Jun; Zhou, Rongqing
2017-08-01
Lactic acid bacteria (LAB) are widely used for the production of a variety of foods and feed raw materials where they contribute to flavor and texture of the fermented products. In addition, specific LAB strains are considered as probiotic due to their health-promoting effects in consumers. Recently, the genome sequencing of LAB is booming and the increased amount of published genomics data brings unprecedented opportunity for us to reveal the important traits of LAB. This review describes the recent progress on LAB genomics and special emphasis is placed on understanding the industry-related physiological features based on genomics analysis. Moreover, strategies to engineer metabolic capacity and stress tolerance of LAB with improved industrial performance are also discussed.
Zhang, Q; Li, X J; Zhao, M M; Yu, Z
2014-10-01
Five LAB strains were evaluated using the acid production ability test, morphological observation, Gram staining, physiological, biochemical and acid tolerance tests. All five strains (LP1, LP2, LP3, LC1 and LC2) grew at pH 4·0, and LP1 grew at 15°C. Strains LP1, LP2 and LP3 were identified as Lactobacillus plantarum, whereas LC1 and LC2 were classified as Lactobacillus casei by sequencing 16S rDNA. The five isolated strains and two commercial inoculants (PS and CL) were added to native grass and Leymus chinensis (Trin.) Tzvel. for ensiling. All five isolated strains decreased the pH and ammonia nitrogen content, increased the lactic acid content and LP1, LP2 and LP3 increased the acetic content and lactic/acetic acid ratio of L. chinensis silage significantly. The five isolated strains and two commercial inoculants decreased the butyric acid content of the native grass silage. LP2 treatment had lower butyric acid content and ammonia nitrogen content than the other treatments. The five isolated strains improved the quality of L. chinensis silage. The five isolated strains and the two commercial inoculants were not effective in improving the fermentation quality of the native grass silage, but LP2 performed better comparatively. Significance and impact of the study: Leymus chinensis is an important grass in China and Russia, being the primary grass of the short grassland 'steppe' regions of central Asia. However, it has been difficult to make high-quality silage of this species because of low concentration of water-soluble carbohydrates (WSC). Isolating and evaluating lactic acid bacteria strains will be helpful for improving the silage quality of this extensively grown species. © 2014 The Society for Applied Microbiology.
Camu, Nicholas; De Winter, Tom; Verbrugghe, Kristof; Cleenwerck, Ilse; Vandamme, Peter; Takrama, Jemmy S.; Vancanneyt, Marc; De Vuyst, Luc
2007-01-01
The Ghanaian cocoa bean heap fermentation process was studied through a multiphasic approach, encompassing both microbiological and metabolite target analyses. A culture-dependent (plating and incubation, followed by repetitive-sequence-based PCR analyses of picked-up colonies) and culture-independent (denaturing gradient gel electrophoresis [DGGE] of 16S rRNA gene amplicons, PCR-DGGE) approach revealed a limited biodiversity and targeted population dynamics of both lactic acid bacteria (LAB) and acetic acid bacteria (AAB) during fermentation. Four main clusters were identified among the LAB isolated: Lactobacillus plantarum, Lactobacillus fermentum, Leuconostoc pseudomesenteroides, and Enterococcus casseliflavus. Other taxa encompassed, for instance, Weissella. Only four clusters were found among the AAB identified: Acetobacter pasteurianus, Acetobacter syzygii-like bacteria, and two small clusters of Acetobacter tropicalis-like bacteria. Particular strains of L. plantarum, L. fermentum, and A. pasteurianus, originating from the environment, were well adapted to the environmental conditions prevailing during Ghanaian cocoa bean heap fermentation and apparently played a significant role in the cocoa bean fermentation process. Yeasts produced ethanol from sugars, and LAB produced lactic acid, acetic acid, ethanol, and mannitol from sugars and/or citrate. Whereas L. plantarum strains were abundant in the beginning of the fermentation, L. fermentum strains converted fructose into mannitol upon prolonged fermentation. A. pasteurianus grew on ethanol, mannitol, and lactate and converted ethanol into acetic acid. A newly proposed Weissella sp., referred to as “Weissella ghanaensis,” was detected through PCR-DGGE analysis in some of the fermentations and was only occasionally picked up through culture-based isolation. Two new species of Acetobacter were found as well, namely, the species tentatively named “Acetobacter senegalensis” (A. tropicalis-like) and
Park, M R; Yun, H S; Son, S J; Oh, S; Kim, Y
2014-11-01
Caenorhabditis elegans is an accepted model host to study host-bacteria interactions in the gut, in addition to being a simple model with which to study conserved aspects of biological signaling pathways in intestinal environments, because these nematode worms have similar intestinal cells to those of humans. Here, we used C. elegans to develop a new in vivo screening system for potential probiotic lactic acid bacteria (LAB). Initially, critical colonization ability of LAB strains isolated from Korean infant feces was screened in the worm intestinal tract over a period of 5 d. Furthermore, we investigated host health-promoting activities, including longevity-extending effects and immune-enhancing activities against foodborne pathogen infection. We identified 4 LAB strains that were highly persistent in the nematode gut and that significantly prolonged the longevity of C. elegans and improved the survival of C. elegans in response to infection by Staphylococcus aureus. The 4 LAB strains we identified showed resistance to acid and bile conditions, assimilated cholesterol, and were able to attach to a mucus layer. The 4 LAB isolates were identified as Lactobacillus plantarum using 16S rRNA sequencing analysis. Taken together, we developed a direct in vivo screening system using C. elegans to study host health-promoting LAB. Our system is simple, rapid, cost-effective, and reliable, and we anticipate that this system will result in the discovery of many more potential probiotic bacteria for dairy foods. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
Takeda, Shiro; Matsufuji, Hisashi; Nakade, Koji; Takenoyama, Shin-Ichi; Ahhmed, Abdulatef; Sakata, Ryoichi; Kawahara, Satoshi; Muguruma, Michio
2017-03-01
In the lactic acid bacteria (LAB) strains screened from our LAB collection, Lactobacillus (L.) sakei strain no. 23 and L. curvatus strain no. 28 degraded meat protein and tolerated salt and nitrite in vitro. Fermented sausages inoculated strains no. 23 and no. 28 showed not only favorable increases in viable LAB counts and reduced pH, but also the degradation of meat protein. The sausages fermented with these strains showed significantly higher antioxidant activity than those without LAB or fermented by each LAB type strain. Angiotensin-I-converting-enzyme (ACE) inhibitory activity was also significantly higher in the sausages fermented with strain no. 23 than in those fermented with the type strain. Higher ACE inhibitory activity was also observed in the sausages fermented with strain no. 28, but did not differ significantly from those with the type strain. An analysis of the proteolysis and degradation products formed by each LAB in sausages suggested that those bioactivities yielded fermentation products such as peptides. Therefore, LAB starters that can adequately ferment meat, such as strains no. 23 and no. 28, should contribute to the production of bioactive compounds in meat products. © 2016 Japanese Society of Animal Science.
Lee, Yeonhee; Lee, Taik-Soo
2005-01-01
Lactic-acid-producing bacteria (LABs) are known to have immunomodulating activity. In the current study, various LABs were tested for their immunity-enhancing activity, especially the phagocytic activity of leukocytes. Viable but not heat-killed cells of Weissella kimchii strain PL9001, Lactobacillus fermentum strain PL9005, and L. plantarum strain PL9011 significantly increased the ex vivo phagocytic capacity of mouse peritoneal leukocytes to ingest fluorescein isothiocyanate (FITC)-labeled Escherichia coli in a strain-dependent manner. Results of this and previous studies suggest these LABs as candidates for new probiotics. This is the first report of the enhancement of peritoneal leukocyte activity of these species.
Lactic acid bacteria inhibit TH2 cytokine production by mononuclear cells from allergic patients.
Pochard, Pierre; Gosset, Philippe; Grangette, Corinne; Andre, Claude; Tonnel, André-Bernard; Pestel, Joël; Mercenier, Annick
2002-10-01
Among factors potentially involved in the increased prevalence of allergic diseases, modification of the intestinal bacteria flora or lack of bacterial stimulation during childhood has been proposed. Lactic acid bacteria (LAB) present in fermented foods or belonging to the natural intestinal microflora were shown to exert beneficial effects on human health. Recent reports have indicated their capacity to reduce allergic symptoms. The purpose of this investigation was to determine the effect of LAB on the production of type 2 cytokines, which characterize allergic diseases. PBMCs from patients allergic to house dust mite versus those from healthy donors were stimulated for 48 hours with the related Dermatophagoides pteronyssinus allergen or with a staphylococcal superantigen. The effect of LAB preincubation was assessed by measuring the type 2 cytokine production by means of specific ELISA. The tested gram-positive LAB were shown to inhibit the secretion of T(H)2 cytokines (IL-4 and IL-5). This effect was dose dependent and was observed irrespective of the LAB strain used. No significant inhibition was induced by the control, gram-negative Escherichia coli TG1. Interestingly, LAB reduced the T(H)2 cytokine production from allergic PBMCs specifically restimulated with the related allergen. The inhibition mechanism was shown to be dependent on antigen-presenting cells (ie, monocytes) and on the involvement of IL-12 and IFN-gamma. The tested LAB strains were demonstrated to exhibit an anti-T(H)2 activity, and thus different strains of this family might be useful in the prevention of allergic diseases.
Identification of Lactic Acid Bacteria from Chili Bo, a Malaysian Food Ingredient
Leisner, Jørgen J.; Pot, Bruno; Christensen, Henrik; Rusul, Gulam; Olsen, John E.; Wee, Bee Wah; Muhamad, Kharidah; Ghazali, Hasanah M.
1999-01-01
Ninety-two strains of lactic acid bacteria (LAB) were isolated from a Malaysian food ingredient, chili bo, stored for up to 25 days at 28°C with no benzoic acid (product A) or with 7,000 mg of benzoic acid kg−1 (product B). The strains were divided into eight groups by traditional phenotypic tests. A total of 43 strains were selected for comparison of their sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) whole-cell protein patterns with a SDS-PAGE database of LAB. Isolates from product A were identified as Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus farciminis, Pediococcus acidilactici, Enterococcus faecalis, and Weissella confusa. Five strains belonging to clusters which could not be allocated to existing species by SDS-PAGE were further identified by 16S rRNA sequence comparison. One strain was distantly related to the Lactobacillus casei/Pediococcus group. Two strains were related to Weissella at the genus or species level. Two other strains did not belong to any previously described 16S rRNA group of LAB and occupied an intermediate position between the L. casei/Pediococcus group and the Weissella group and species of Carnobacterium. The latter two strains belong to the cluster of LAB that predominated in product B. The incidence of new species and subspecies of LAB in chili bo indicate the high probability of isolation of new LAB from certain Southeast Asian foods. None of the isolates exhibited bacteriocin activity against L. plantarum ATCC 14917 and LMG 17682. PMID:9925588
A new laboratory cultivation of Paramecium bursaria using non-pathogenic bacteria strains.
Bator, Tomasz
2010-01-01
In most studies dealing with the laboratory cultivation of paramecia (Paramecium bursaria), Klebsiella pneumoniae bacteria are used to inoculate the medium. However, Klebsiella pneumoniae is a typical pathogen, and its use is always associated with a risk of infection. The aim of the present research was to examine non-pathogenic bacteria strains as components of the medium for Paramecium bursaria. The paramecia were incubated on lettuce infusions bacterized with different bacteria strains: Bacillus subtilis DSM 10, Bacillus megaterium DSM 32, Escherichia coli DSM 498, Micrococcus luteus DSM 348. A strain derived from the natural habitat of Paramecium bursaria was used as the control one. Experiments were conducted under constant light and in the dark. Paramecia cells were counted under a stereomicroscope on consecutive days of incubation. The obtained results show that the most intensive growth of Paramecium bursaria occurs in the presence of Escherichia coli DSM 498. The use of this strain as a component of the medium allows one to obtain a high number of ciliates regardless of the light conditions. It can be concluded that the Paramecium bursaria cultivation procedure can be modified by using the non-pathogenic bacteria strain Escherichia coli DSM 498 instead of Klebsiella pneumoniae.
USDA-ARS?s Scientific Manuscript database
Lactic acid bacteria (LAB) have been widely used in the production of fermented foods and as probiotics. Alternan is a glucan with a distinctive backbone structure of alternating alpha-(1,6) and alpha-(1,3) linkages produced by the LAB Leuconostoc mesenteroides. In recent years, improved strains f...
Linking wine lactic acid bacteria diversity with wine aroma and flavour.
Cappello, Maria Stella; Zapparoli, Giacomo; Logrieco, Antonio; Bartowsky, Eveline J
2017-02-21
In the last two decades knowledge on lactic acid bacteria (LAB) associated with wine has increased considerably. Investigations on genetic and biochemistry of species involved in malolactic fermentation, such as Oenococcus oeni and of Lactobacillus have enabled a better understand of their role in aroma modification and microbial stability of wine. In particular, the use of molecular techniques has provided evidence on the high diversity at species and strain level, thus improving the knowledge on wine LAB taxonomy and ecology. These tools demonstrated to also be useful to detect strains with potential desirable or undesirable traits for winemaking purposes. At the same time, advances on the enzymatic properties of wine LAB responsible for the development of wine aroma molecules have been undertaken. Interestingly, it has highlighted the high intraspecific variability of enzymatic activities such as glucosidase, esterase, proteases and those related to citrate metabolism within the wine LAB species. This genetic and biochemistry diversity that characterizes wine LAB populations can generate a wide spectrum of wine sensory outcomes. This review examines some of these interesting aspects as a way to elucidate the link between LAB diversity with wine aroma and flavour. In particular, the correlation between inter- and intra-species diversity and bacterial metabolic traits that affect the organoleptic properties of wines is highlighted with emphasis on the importance of enzymatic potential of bacteria for the selection of starter cultures to control MLF and to enhance wine aroma. Copyright © 2016 Elsevier B.V. All rights reserved.
Diversity of lactic acid bacteria associated with traditional fermented dairy products in Mongolia.
Yu, J; Wang, W H; Menghe, B L G; Jiri, M T; Wang, H M; Liu, W J; Bao, Q H; Lu, Q; Zhang, J C; Wang, F; Xu, H Y; Sun, T S; Zhang, H P
2011-07-01
Spontaneous milk fermentation has a long history in Mongolia, and beneficial microorganisms have been handed down from one generation to the next for use in fermented dairy products. The objective of this study was to investigate the diversity of lactic acid bacteria (LAB) communities in fermented yak, mare, goat, and cow milk products by analyzing 189 samples collected from 13 different regions in Mongolia. The LAB counts in these samples varied from 3.41 to 9.03 log cfu/mL. Fermented yak and mare milks had almost identical mean numbers of LAB, which were significantly higher than those in fermented goat milk but slightly lower than those in fermented cow milk. In total, 668 isolates were obtained from these samples using de Man, Rogosa, and Sharpe agar and M17 agar. Each isolate was considered to be presumptive LAB based on gram-positive and catalase-negative properties, and was identified at the species level by 16S rRNA gene sequencing, multiplex PCR assay, and restriction fragment length polymorphism analysis. All isolates from Mongolian dairy products were accurately identified as Enterococcus faecalis (1 strain), Enterococcus durans (3 strains), Lactobacillus brevis (3 strains), Lactobacillus buchneri (2 strains), Lactobacillus casei (16 strains), Lactobacillus delbrueckii ssp. bulgaricus (142 strains), Lactobacillus diolivorans (17 strains), Lactobacillus fermentum (42 strains), Lactobacillus helveticus (183 strains), Lactobacillus kefiri (6 strains), Lactobacillus plantarum ssp. plantarum (7 strains), Lactococcus lactis ssp. lactis (7 strains), Leuconostoc lactis (22 strains), Leuconostoc mesenteroides (21 strains), Streptococcus thermophilus (195 strains), and Weissella cibaria (1 strain). The predominant LAB were Strep. thermophilus and Lb. helveticus, which were isolated from all sampling sites. The results demonstrate that traditional fermented dairy products from different regions of Mongolia have complex compositions of LAB species. Such diversity of
Probiotic Properties of Lactobacillus Strains Isolated from Tibetan Kefir Grains
Zheng, Yongchen; Lu, Yingli; Wang, Jinfeng; Yang, Longfei; Pan, Chenyu; Huang, Ying
2013-01-01
The objective of this study was to evaluate the functional properties of lactic acid bacteria (LAB) isolated from Tibetan kefir grains. Three Lactobacillus isolates identified as Lactobacillus acidophilus LA15, Lactobacillus plantarum B23 and Lactobacillus kefiri D17 that showed resistance to acid and bile salts were selected for further evaluation of their probiotic properties. The 3 selected strains expressed high in vitro adherence to Caco-2 cells. They were sensitive to gentamicin, erythromycin and chloramphenicol and resistant to vancomycin with MIC values of 26 µg/ml. All 3 strains showed potential bile salt hydrolase (BSH) activity, cholesterol assimilation and cholesterol co-precipitation ability. Additionally, the potential effect of these strains on plasma cholesterol levels was evaluated in Sprague-Dawley (SD) rats. Rats in 4 treatment groups were fed the following experimental diets for 4 weeks: a high-cholesterol diet, a high-cholesterol diet plus LA15, a high-cholesterol diet plus B23 or a high-cholesterol diet plus D17. The total cholesterol, triglyceride and low-density lipoprotein cholesterol levels in the serum were significantly (P<0.05) decreased in the LAB-treated rats compared with rats fed a high-cholesterol diet without LAB supplementation. The high-density lipoprotein cholesterol levels in groups B23 and D17 were significantly (P<0.05) higher than those in the control and LA15 groups. Additionally, both fecal cholesterol and bile acid levels were significantly (P<0.05) increased after LAB administration. Fecal lactobacilli counts were significantly (P<0.05) higher in the LAB treatment groups than in the control groups. Furthermore, the 3 strains were detected in the rat small intestine, colon and feces during the feeding trial. The bacteria levels remained high even after the LAB administration had been stopped for 2 weeks. These results suggest that these strains may be used in the future as probiotic starter cultures for manufacturing
Biopolymers from lactic acid bacteria. Novel applications in foods and beverages
Torino, María I.; Font de Valdez, Graciela; Mozzi, Fernanda
2015-01-01
Lactic acid bacteria (LAB) are microorganisms widely used in the fermented food industry worldwide. Certain LAB are able to produce exopolysaccharides (EPS) either attached to the cell wall (capsular EPS) or released to the extracellular environment (EPS). According to their composition, LAB may synthesize heteropolysaccharides or homopolysaccharides. A wide diversity of EPS are produced by LAB concerning their monomer composition, molecular mass, and structure. Although EPS-producing LAB strains have been traditionally applied in the manufacture of dairy products such as fermented milks and yogurts, their use in the elaboration of low-fat cheeses, diverse type of sourdough breads, and certain beverages are some of the novel applications of these polymers. This work aims to collect the most relevant issues of the former reviews concerning the monomer composition, structure, and yields and biosynthetic enzymes of EPS from LAB; to describe the recently characterized EPS and to present the application of both EPS-producing strains and their polymers in the fermented (specifically beverages and cereal-based) food industry. PMID:26441845
Demonstrating Effectiveness of Antibiotics Against Known Bacteria Strains
ERIC Educational Resources Information Center
Keefe, Lois M.
1977-01-01
Procedures are described for showing the effectiveness of antibiotics (penicillin, ampicillin, and tetracycline) against a nonpathogenic bacteria strain (Bacillus cereus). Methods are outlined for preparing nutrient agar, sterilizing tubes, pouring agar plates, preparing antibiotic discs, and transferring antibiotic discs to agar plates. (CS)
Collado, M Carmen; Surono, Ingrid S; Meriluoto, Jussi; Salminen, Seppo
2007-03-01
Traditional fermented buffalo milk in Indonesia (dadih) has been believed to have a beneficial impact on human health, which could be related to the properties of the lactic acid bacteria (LAB) involved in its fermentation process. In previous studies, it was discovered that strains of dadih lactic isolates possessed some beneficial properties in vitro. In the present study, the adhesion capacity of specific LAB isolates from dadih to intestinal mucus was analyzed. Further, the ability to inhibit model human pathogens and displace them from mucus was assessed. The adhesion of tested LAB strains was strain-dependent and varied from 1.4 to 9.8%. The most adhesive Lactobacillus plantarum strain was IS-10506, with 9.8% adhesion. The competition assay between dadih LAB isolates and pathogens showed that a 2-h preincubation with L. plantarum at 37 degrees C significantly reduced pathogen adhesion to mucus. All tested LAB strains displaced and inhibited pathogen adhesion, but the results were strain-specific and dependent on time and pathogen strains. In general, L. plantarum IS-10506 showed the best ability against pathogen adhesion.
Shangpliang, H. N. J.; Sharma, Sharmila; Rai, Ranjita; Tamang, Jyoti P.
2017-01-01
Dahi and datshi are common naturally fermented milk (NFM) products of Bhutan. Population of lactic acid bacteria (LAB) in dahi (pH 3.7) and datshi (pH 5.2) was 1.4 × 107 and 3.9 × 108 cfu/ml, respectively. Based on 16S rRNA gene sequencing isolates of LAB from dahi and datshi were identified as Enterococcus faecalis, E. faecium, Lactococcus lactis subsp. lactis. LAB strains were tested for some technological properties. All LAB strains except E. faecalis CH2:17 caused coagulation of milk at both 30°C for 48 h. Only E. faecium DH4:05 strain was resistant to pH 3. No significant difference (P > 0.05) of viable counts was observed in MRS broth with and without lysozyme. All LAB strains grew well in 0.3% bile showing their ability to tolerate bile salt. None of the LAB strains showed >70% hydrophobicity. This study, being the first of its microbiological analysis of the NFM of Bhutan, has opened up to an extent of research work that gives a new insight to the products. PMID:28203227
Genetic and technological characterisation of vineyard- and winery-associated lactic acid bacteria.
Nisiotou, Aspasia A; Dourou, Dimitra; Filippousi, Maria-Evangelia; Diamantea, Ellie; Fragkoulis, Petros; Tassou, Chryssoula; Banilas, Georgios
2015-01-01
Vineyard- and winery-associated lactic acid bacteria (LAB) from two major PDO regions in Greece, Peza and Nemea, were surveyed. LAB were isolated from grapes, fermenting musts, and winery tanks performing spontaneous malolactic fermentations (MLF). Higher population density and species richness were detected in Nemea than in Peza vineyards and on grapes than in fermenting musts. Pediococcus pentosaceus and Lactobacillus graminis were the most abundant LAB on grapes, while Lactobacillus plantarum dominated in fermenting musts from both regions. No particular structure of Lactobacillus plantarum populations according to the region of origin was observed, and strain distribution seems random. LAB species diversity in winery tanks differed significantly from that in vineyard samples, consisting principally of Oenococcus oeni. Different strains were analysed as per their enological characteristics and the ability to produce biogenic amines (BAs). Winery-associated species showed higher resistance to low pH, ethanol, SO2, and CuSO4 than vineyard-associated isolates. The frequency of BA-producing strains was relatively low but not negligible, considering that certain winery-associated Lactobacillus hilgardii strains were able to produce BAs. Present results show the necessity of controlling the MLF by selected starters in order to avoid BA accumulation in wine.
Zuo, F L; Feng, X J; Chen, L L; Chen, S W
2014-11-01
Thirty strains of lactic acid bacteria (LAB) were isolated from herders' traditional dairy products collected from Xinjiang, China. The species Lactobacillus, Lactococcus, Enterococcus, Pediococcus and Leuconostoc were identified by 16S ribosomal RNA gene sequencing analysis and conventional observation. The strains' fermentation characteristics, including milk acidification, proteolysis, autolysis, antimicrobial activity and diacetyl production, were assayed and compared. Strains NL24 and NL31 showed the highest proteolytic activity-2·75 and 2·08 mmol Phe l(-1) milk, respectively. Strains C, NL41, SW2, Z3-11, NL42 and Z2-91 had high autolytic activity. In addition, most of the wild strains produced diacetyl, half of them to high levels. This study provides a clue to LAB biodiversity in traditional dairy foods produced by herders in the western Tianshan Mountains. High-performing strains should be further evaluated for practical application in value-added fermented dairy products. Our results reveal a certain variety of lactic acid bacteria (LAB) in traditional dairy products from Xinjiang. Some of the LAB strains, such as Lactobacillus rhamnosus NL24 and Lactobacillus paracasei SW2, possess excellent functional properties and have the potential for application in indigenous fermented dairy products. Performance of the newly isolated strains in cheese or yogurt manufacturing was further evaluated. Application of the high-performing strains to enrich the flavour of fermented dairy products is highly desirable and holds great commercial potential. © 2014 The Society for Applied Microbiology.
Gomółka-Pawlicka, M; Uradziński, J
2003-01-01
The aim of this study was to determine of influence of 15 strains of lactic acid bacteria on the growth of 7 Salmonella spp. strains in model set-ups, and in meat and ripened fermented sausages. The investigations were performed within the framework of three alternate stages which differed in respect to the products studied, the number of Lactobacillus spp. strains and, partly, methodological approach. The ratio between lactic acid bacteria and Salmonella strains studied was, depending on the alternate, 1:1, 1:2 and 2:1, respectively. The investigations also covered the water activity (a(w)) and pH of the tested products. The results obtained are shown in 12 figures and suggest that all the lactic acid bacteria strains used within the framework of the model set-ups showed antagonistic effect on all the Salmonella spp. strains. However, these abilities were not observed with respect to some lactic acid bacteria strains in meat and fermented sausage. The temperature and length of the incubation period of sausages, but not a(w) and pH, were found to have a distinct influence on the antagonistic interaction between the bacteria.
Biochemical characterisation of the esterase activities of wine lactic acid bacteria.
Matthews, Angela; Grbin, Paul R; Jiranek, Vladimir
2007-11-01
Esters are an important group of volatile compounds that can contribute to wine flavour. Wine lactic acid bacteria (LAB) have been shown to produce esterases capable of hydrolysing ester substrates. This study aims to characterise the esterase activities of nine LAB strains under important wine conditions, namely, acidic conditions, low temperature (to 10 degrees C) and in the presence of ethanol (2-18% v/v). Esterase substrate specificity was also examined using seven different ester substrates. The bacteria were generally found to have a broad pH activity range, with the majority of strains showing maximum activity close to pH 6.0. Exceptions included an Oenococcus oeni strain that retained most activity even down to a pH of 4.0. Most strains exhibited highest activity across the range 30-40 degrees C. Increasing ethanol concentration stimulated activity in some of the strains. In particular, O. oeni showed an increase in activity up to a maximum ethanol concentration of around 16%. Generally, strains were found to have greater activity towards short-chained esters (C2-C8) compared to long-chained esters (C10-C18). Even though the optimal physicochemical conditions for enzyme activity differed from those found in wine, these findings are of potential importance to oenology because significant activities remained under wine-like conditions.
Nsogning, Sorelle Dongmo; Fischer, Susann; Becker, Thomas
2018-08-01
Understanding lactic acid bacteria (LAB) fermentation behavior in malt wort is a milestone towards flavor improvement of lactic acid fermented malt beverages. Therefore, this study aims to outline deficiencies that may exist in malt wort fermentation. First, based on six LAB strains, cell viability and vitality were evaluated. Second, sugars, organic acids, amino acids, pH value and buffering capacity (BC) were monitored. Finally, the implication of key amino acids, fructose and wort BC on LAB growth was determined. Short growth phase coupled with prompt cell death and a decrease in metabolic activity was observed. Low wort BC caused rapid pH drop with lactic acid accumulation, which conversely increased the BC leading to less pH change at late-stage fermentation. Lactic acid content (≤3.9 g/L) was higher than the reported inhibitory concentration (1.8 g/L). Furthermore, sugars were still available but fructose and key amino acids lysine, arginine and glutamic acid were considerably exhausted (≤98%). Wort supplementations improved cell growth and viability leading to conclude that key amino acid depletion coupled with low BC limits LAB growth in malt wort. Then, a further increase in organic acid reduces LAB viability. This knowledge opens doors for LAB fermentation process optimization in malt wort. Copyright © 2018 Elsevier Ltd. All rights reserved.
Growth characterization of individual rye sourdough bacteria by isothermal microcalorimetry.
Mihhalevski, A; Sarand, I; Viiard, E; Salumets, A; Paalme, T
2011-02-01
The present work tests the feasibility of the isothermal microcalorimetry method to study the performance of individual lactic acid bacteria during solid-state fermentation in rye sourdough. Another aim was to elucidate the key factors leading to the formation of different microbial consortia in laboratory and industrial sourdough during continuous backslopping propagation. Strains of the individual LAB isolated from industrial and laboratory sourdough cycle were grown in 10 kGy irradiated rye dough in vials of an isothermal calorimeter and the power-time curves were obtained. Sugars, organic acids and free amino acids in the sourdough were measured. The OD-time curves of the LAB strains during growth in flour extract or MRS (De Man, Rogosa and Sharpe) broth were also determined. The maximum specific growth rates of Lactobacillus sakei, Lactobacillus brevis, Lactobacillus curvatus and Leuconostoc citreum strains that dominated in backslopped laboratory sourdough were higher than those of Lactobacillus helveticus, Lactobacillus panis, Lactobacillus vaginalis, Lactobacillus casei and Lactobacillus pontis strains originating from industrial sourdough. Industrial strains had higher specific growth rates below pH 4·8. It was supposed that during long-run industrial backslopping processes, the oxygen sensitive species start to dominate because of the O(2) protective effect of rye sourdough. Measurements of the power-time curves revealed that the LAB strains dominating in the industrial sourdough cycle had better acid tolerance but lower maximum growth rate and oxygen tolerance than species isolated from a laboratory sourdough cycle. Isothermal microcalorimetry combined with chemical analysis is a powerful method for characterization of sourdough fermentation process and determination of growth characteristics of individual bacteria in sourdough. © 2010 The Authors. Journal of Applied Microbiology © 2010 The Society for Applied Microbiology.
De Vuyst, Luc; Schrijvers, Vincent; Paramithiotis, Spiros; Hoste, Bart; Vancanneyt, Marc; Swings, Jean; Kalantzopoulos, George; Tsakalidou, Effie; Messens, Winy
2002-01-01
Lactic acid bacteria (LAB) were isolated from Greek traditional wheat sourdoughs manufactured without the addition of baker's yeast. Application of sodium dodecyl sulfate-polyacrylamide gel electrophoresis of total cell protein, randomly amplified polymorphic DNA-PCR, DNA-DNA hybridization, and 16S ribosomal DNA sequence analysis, in combination with physiological traits such as fructose fermentation and mannitol production, allowed us to classify the isolated bacteria into the species Lactobacillus sanfranciscensis, Lactobacillus brevis, Lactobacillus paralimentarius, and Weissella cibaria. This consortium seems to be unique for the Greek traditional wheat sourdoughs studied. Strains of the species W. cibaria have not been isolated from sourdoughs previously. No Lactobacillus pontis or Lactobacillus panis strains were found. An L. brevis-like isolate (ACA-DC 3411 t1) could not be identified properly and might be a new sourdough LAB species. In addition, fermentation capabilities associated with the LAB detected have been studied. During laboratory fermentations, all heterofermentative sourdough LAB strains produced lactic acid, acetic acid, and ethanol. Mannitol was produced from fructose that served as an additional electron acceptor. In addition to glucose, almost all of the LAB isolates fermented maltose, while fructose as the sole carbohydrate source was fermented by all sourdough LAB tested except L. sanfranciscensis. Two of the L. paralimentarius isolates tested did not ferment maltose; all strains were homofermentative. In the presence of both maltose and fructose in the medium, induction of hexokinase activity occurred in all sourdough LAB species mentioned above, explaining why no glucose accumulation was found extracellularly. No maltose phosphorylase activity was found either. These data produced a variable fermentation coefficient and a unique sourdough metabolite composition. PMID:12450829
De Vuyst, Luc; Schrijvers, Vincent; Paramithiotis, Spiros; Hoste, Bart; Vancanneyt, Marc; Swings, Jean; Kalantzopoulos, George; Tsakalidou, Effie; Messens, Winy
2002-12-01
Lactic acid bacteria (LAB) were isolated from Greek traditional wheat sourdoughs manufactured without the addition of baker's yeast. Application of sodium dodecyl sulfate-polyacrylamide gel electrophoresis of total cell protein, randomly amplified polymorphic DNA-PCR, DNA-DNA hybridization, and 16S ribosomal DNA sequence analysis, in combination with physiological traits such as fructose fermentation and mannitol production, allowed us to classify the isolated bacteria into the species Lactobacillus sanfranciscensis, Lactobacillus brevis, Lactobacillus paralimentarius, and Weissella cibaria. This consortium seems to be unique for the Greek traditional wheat sourdoughs studied. Strains of the species W. cibaria have not been isolated from sourdoughs previously. No Lactobacillus pontis or Lactobacillus panis strains were found. An L. brevis-like isolate (ACA-DC 3411 t1) could not be identified properly and might be a new sourdough LAB species. In addition, fermentation capabilities associated with the LAB detected have been studied. During laboratory fermentations, all heterofermentative sourdough LAB strains produced lactic acid, acetic acid, and ethanol. Mannitol was produced from fructose that served as an additional electron acceptor. In addition to glucose, almost all of the LAB isolates fermented maltose, while fructose as the sole carbohydrate source was fermented by all sourdough LAB tested except L. sanfranciscensis. Two of the L. paralimentarius isolates tested did not ferment maltose; all strains were homofermentative. In the presence of both maltose and fructose in the medium, induction of hexokinase activity occurred in all sourdough LAB species mentioned above, explaining why no glucose accumulation was found extracellularly. No maltose phosphorylase activity was found either. These data produced a variable fermentation coefficient and a unique sourdough metabolite composition.
Koo, Ok-Kyung; Eggleton, Mallory; O'Bryan, Corliss A; Crandall, Philip G; Ricke, Steven C
2012-12-01
Contamination by Listeria monocytogenes has been a constant public health threat for the ready-to-eat (RTE) meat industry due to the potential for high mortalities from listeriosis. Lactic acid bacteria (LAB) have shown protective action against various pathogenic bacteria. The aim of this study was to evaluate the antilisterial activity of a combination of three LAB strains (Lactiguard®) on L. monocytogenes. The combination of the LAB was inhibitory to L. monocytogenes inoculated onto frankfurters not containing lactate/diacetate after 8weeks of refrigerated storage (0.6 log reduction compared to L. monocytogenes only control), and when a cell free extract (CFS) of the LAB was added with LAB even more inhibition was obtained (1.2 log reduction compared with L. monocytogenes only). In frankfurters containing lactate/diacetate the LAB and the LAB plus CFS were more effective in reducing growth of L. monocytogenes after 8 weeks of refrigerated storage (2 and 3.3 log reductions respectively). Copyright © 2012 Elsevier Ltd. All rights reserved.
Nievas, Fiorela L; Bogino, Pablo C; Giordano, Walter
2016-05-06
Biochemistry courses in the Department of Molecular Biology at the National University of Río Cuarto, Argentina, are designed for undergraduate students in biology, microbiology, chemistry, agronomy, and veterinary medicine. Microbiology students typically have previous coursework in general, analytical, and organic chemistry. Programmed sequences of lab experiments allow these students to investigate biochemical problems whose solution is feasible within the context of their knowledge and experience. We previously designed and reported a programmed lab experiment that familiarizes microbiology students with techniques for detection and characterization of quorum-sensing (QS) and quorum-quenching (QQ) signal molecules. Here, we describe a sequence of experiments designed to expand the understanding and capabilities of biochemistry students using techniques for extraction and identification of QS and QQ signal molecules from peanut rhizospheric soil bacteria, including culturing and manipulation of bacteria under sterile conditions. The program provides students with an opportunity to perform useful assays, draw conclusions from their results, and discuss possible extensions of the study. © 2016 by The International Union of Biochemistry and Molecular Biology, 44:256-262, 2016. © 2016 The International Union of Biochemistry and Molecular Biology.
Grosu-Tudor, Silvia-Simona; Stancu, Mihaela-Marilena; Pelinescu, Diana; Zamfir, Medana
2014-09-01
Lactic acid bacteria (LAB) isolated from different sources (dairy products, fruits, fresh and fermented vegetables, fermented cereals) were screened for antimicrobial activity against other bacteria, including potential pathogens and food spoiling bacteria. Six strains have been shown to produce bacteriocins: Lactococcus lactis 19.3, Lactobacillus plantarum 26.1, Enterococcus durans 41.2, isolated from dairy products and Lactobacillus amylolyticus P40 and P50, and Lactobacillus oris P49, isolated from bors. Among the six bacteriocins, there were both heat stable, low molecular mass polypeptides, with a broad inhibitory spectrum, probably belonging to class II bacteriocins, and heat labile, high molecular mass proteins, with a very narrow inhibitory spectrum, most probably belonging to class III bacteriocins. A synergistic effect of some bacteriocins mixtures was observed. We can conclude that fermented foods are still important sources of new functional LAB. Among the six characterized bacteriocins, there might be some novel compounds with interesting features. Moreover, the bacteriocin-producing strains isolated in our study may find applications as protective cultures.
Ruiz Rodríguez, L; Vera Pingitore, E; Rollan, G; Cocconcelli, P S; Fontana, C; Saavedra, L; Vignolo, G; Hebert, E M
2016-05-01
To analyse lactic acid bacteria (LAB) diversity and technological-functional and safety properties of strains present during spontaneous fermented quinoa sourdoughs. Fermentation was performed by daily backslopping at 30°C for 10 days. Autochthonous LAB microbiota was monitored by a biphasic approach combining random amplified polymorphic DNA (RAPD)-PCR and rRNA gene sequencing with PCR-denaturing gradient gel electrophoresis (DGGE) analysis. Identification and intraspecies differentiation allowed to group isolates within nine LAB species belonging to four genera. A succession of LAB species occurred during 10-days backslopping; Lactobacillus plantarum and Lactobacillus brevis were detected as dominant species in the consortium. The characterization of 15 representative LAB strains was performed based on the acidifying capacity, starch and protein hydrolysis, γ-aminobutyric acid and exopolysaccharides production, antimicrobial activity and antibiotic resistance. Strains characterization led to the selection of Lact. plantarum CRL1905 and Leuconostoc mesenteroides CRL1907 as candidates to be assayed as functional starter culture for the gluten-free (GF) quinoa fermented products. Results on native LAB microbiota present during quinoa sourdough fermentation will allow the selection of strains with appropriate technological properties to be used as a novel functional starter culture for GF-fermented products. © 2016 The Society for Applied Microbiology.
Some current applications, limitations and future perspectives of lactic acid bacteria as probiotics
Evivie, Smith Etareri; Huo, Gui-Cheng; Igene, John Oamen; Bian, Xin
2017-01-01
ABSTRACT Several mechanism and non-mechanism-based studies supporting the claim that lactic acid bacteria (LAB) strains confer health benefits and play immune-modulatory roles were examined in this review. Probiotic applications of LAB on global burdens such as obesity and type-2 diabetes were discussed as well as the use of yoghurt and ice cream as important vehicles to convey several beneficial LAB strains. Probiotic and symbiotic dairy products may be used in the nearest future to treat a variety of health disorders. Current studies suggest that lactic acid bacteria possess anti-obesity and anti-diabetic propensities on their hosts and thus can play a crucial role in human health care. Research in the rheological and physicochemical properties of ice cream as well as its applications are also on the increase. These applications face certain hurdles including technological (for less developed countries), consumer acceptability of new functional foods may be influenced by culture, ethics or religion. There is need for more studies on the genetic basis for probiotic properties which will give further understanding regarding novel manipulation skills and applicability in nutrition and health sectors. More studies confirming the direct effects of probiotic LABs in lowering the spread of food-borne and other pathogens are also anticipated. PMID:28659729
Chao, Shiou-Huei; Wu, Ruei-Jie; Watanabe, Koichi; Tsai, Ying-Chieh
2009-11-15
Fu-tsai and suan-tsai are spontaneously fermented mustard products traditionally prepared by the Hakka tribe of Taiwan. We chose 5 different processing stages of these products for analysis of the microbial community of lactic acid bacteria (LAB) by 16S rRNA gene sequencing. From 500 LAB isolates we identified 119 representative strains belonging to 5 genera and 18 species, including Enterococcus (1 species), Lactobacillus (11 species), Leuconostoc (3 species), Pediococcus (1 species), and Weissella (2 species). The LAB composition of mustard fermented for 3 days, known as the Mu sample, was the most diverse, with 11 different LAB species being isolated. We used sequence analysis of the 16S rRNA gene to identify the LAB strains and analysis of the dnaA, pheS, and rpoA genes to identify 13 LAB strains for which identification by 16S rRNA gene sequences was not possible. These 13 strains were found to belong to 5 validated known species: Lactobacillus farciminis, Leuconostoc mesenteroides, Leuconostoc pseudomesenteroides, Weissella cibaria, and Weissella paramesenteroides, and 5 possibly novel Lactobacillus species. These results revealed that there is a high level of diversity in LAB at the different stages of fermentation in the production of suan-tsai and fu-tsai.
Lactic acid bacteria isolated from apples are able to catabolise arginine.
Savino, María J; Sánchez, Leandro A; Saguir, Fabiana M; de Nadra, María C Manca
2012-03-01
We investigated the potentiality of lactic acid bacteria (LAB) isolated from two apples variety to utilize arginine at different initial pH values. Apples surface contained average levels of bacteria ranging from log 2.49 ± 0.53 to log 3.73 ± 0.48 cfu/ml for Red Delicious and Golden Delicious varieties, respectively. Thirty-one strains able to develop in presence of arginine at low pH were phenotypically and genotipically identified as belonging to Lactobacillus, Pediococcus and Leuconostoc genera. In general, they did not produce ammonia from arginine when cultivated in basal medium with arginine (BMA) at pH 4.5 or 5.2. When this metabolite was quantified only six strains belonging to Leuconostoc dextranicum, Lactobacillus brevis and Lactobacillus plantarum species formed higher ammonia amounts in BMA as compared to control. This was correlated with arginine utilization and it was more pronounced at pH 4.5 than 5.2. Analysis of citrulline production confirmed the arginine utilization in these bacteria by the arginine deiminase (ADI) pathway. Maxima citrulline production was observed for Lactobacillus brevis M15 at the two pH values. In this strain ammonia was formed at higher rate than citrulline, which was detected in concentration lower than 1 mM. Thus, main LAB species found on apple surfaces with abilities to degrade arginine by the ADI pathway under different conditions were reported here at the first time. The results suggested that the ADI pathway in apples LAB might not be mainly relevant for their survival in the acid natural environmental, despite leading to the ammonia formation, which may contribute to the increase in pH, coping the acid stress.
Biodiversity of Lactobacillus sanfranciscensis strains isolated from five sourdoughs.
Kitahara, M; Sakata, S; Benno, Y
2005-01-01
Five different sourdoughs were investigated for the composition of lactic acid bacteria (LAB) and the biodiversity of Lactobacillus sanfranciscensis strains. A total of 57 strains were isolated from five sourdoughs. Isolated strains were all identified by the 16S rDNA sequence and species-specific primers for L. sanfranciscensis. Results of identification showed that LAB strains were L. sanfranciscensis, Lactobacillus plantarum, Lactobacillus paralimentarius, Lactobacillus fermentum, Lactobacillus pontis, Lactobacillus casei, Weisella confusa and Pediococcus pentosaceus. A total of 21 strains were identified as L. sanfranciscensis and these isolates were detected in all five sourdoughs. Ribotyping was applied to investigate the relationship between intraspecies diversity of L. sanfranciscensis and sourdough. A total of 22 strains of L. sanfranciscensis including L. sanfranciscensis JCM 5668T were compared by ribotyping. The dendrogram of 21 ribotyping patterns showed four clusters, and L. sanfranciscensis JCM 5668T was independent of the others. The different biotypes of L. sanfranciscensis were present in two sourdoughs compared with other three sourdoughs. The LAB compositions of five sourdoughs were different and the relationship between intraspecies diversity of L. sanfranciscensis strains and five sourdoughs was shown by ribotyping. This study demonstrated that ribotyping was useful for distinguishing L. sanfranciscensis strains. A further important result is that the intra-species diversity of L. sanfranciscensis strains seems to be related to the sourdough preparation.
The depletion of sodium nitrite by lactic acid bacteria isolated from kimchi.
Oh, Chang-Kyung; Oh, Myung-Chul; Kim, Soo-Hyun
2004-01-01
Nitrites, whether added or naturally occurring in foods, are potential carcinogens, and controlling their concentrations is important for maintaining a safe food supply. In this study we investigated the depletion of sodium nitrite (150 microg/mL) during the fermentation in Lactobacilli MRS broth at 5, 10, 15, 20, 25, 30, and 36 degrees C by lactic acid bacteria (LAB-A, -B, -C, and -D) isolated from kimchi and Leuconostoc mesenteroides strain KCTC3100. The four species of lactic acid bacteria isolated from kimchi were identified as L. mesenteroides, and all produced depletion of less than 20% of sodium nitrite after 10 days of incubation at 5 degrees C. There was less than 40% depletion after 9 days at 10 degrees C, 86.4-92.8% after 7 days at 15 degrees C, 81.4-87.8% after 4 days and more than 90.0% after 5 days at 20 degrees C, 76.3-85.7% after 3 days and more than 90.0% after 5 days at 25 degrees C, and more than 90.0% after 2 days at 30 and 36 degrees C. The depletion by LAB isolates was similar or higher than that by L. mesenteroides strain KCTC3100, and in particular, the LAB-D strain showed the highest depletion effect of all the strains tested, up to 15 degrees C. From these results, the strains isolated from kimchi were very effective for the depletion of sodium nitrite at high temperature, and all sodium nitrite was depleted at the initial period of incubation (1-2 days) at 30 and 36 degrees C. But as the temperature was lowered, the depletion effect of sodium nitrite was decreased in all the strains tested from kimchi. This illustrates that the depletion of nitrite by each strain is subject to the influence of temperatures.
NASA Astrophysics Data System (ADS)
März, Anne; Mönch, Bettina; Walter, Angela; Bocklitz, Thomas; Schumacher, Wilm; Rösch, Petra; Kiehntopf, Michael; Popp, Jürgen
2011-07-01
This contribution will present a variety of applications of lab-on-a-chip surface enhanced Raman spectroscopy in the field of bioanalytic. Beside the quantification and online monitoring of drugs and pharmaceuticals, determination of enzyme activity and discrimination of bacteria are successfully carried out utilizing LOC-SERS. The online-monitoring of drugs using SERS in a microfluidic device is demonstrated for nicotine. The enzyme activity of thiopurine methyltransferase (TPMT) in lysed red blood cells is determined by SERS in a lab-on-a-chip device. To analyse the activity of TPMT the metabolism of 6-mercaptopurine to 6-methylmercaptopurine is investigated. The discrimination of bacteria on strain level is carried out with different E. coli strains. For the investigations, the bacteria are busted by ultra sonic to achieve a high information output. This sample preparation provides the possibility to detect SERS spectra containing information of the bacterial cell walls as well as of the cytoplasm. This contribution demonstrates the great potential of LOC-SERS in the field of bioanalytics.
Occurrence and role of lactic acid bacteria in seafood products.
Françoise, Leroi
2010-09-01
Lactic acid bacteria (LAB) in fish flesh has long been disregarded because the high post-mortem pH, the low percentage of sugars, the high content of low molecular weight nitrogenous molecules and the low temperature of temperate waters favor the rapid growth of pH-sensitive psychrotolerant marine Gram-negative bacteria like Pseudomonas, Shewanella and Photobacterium. In seafood packed in both vacuum (VP) and modified atmosphere (MAP) packaging commonly CO(2) enriched, the growth of the Gram-negative aerobic bacteria group (predominantly pseudomonads) is effectively inhibited and the number reached by LAB during storage is higher than that achieved in air but always several log units lower than the trimethylamine oxide (TMA-O) reducing and CO(2)-resistant organisms (Shewanella putrefaciens and Photobacterium phosphoreum). Accordingly, LAB are not of much concern in seafood neither aerobically stored nor VP and MAP. However, they may acquire great relevance in lightly preserved fish products (LPFP), including those VP or MAP. Fresh fish presents a very high water activity (aw) value (0.99). However, aw is reduced to about 0.96 when salt (typically 6% WP) is added to the product. As a result, aerobic Gram-negative bacteria are inhibited, which allows the growth of other organisms more resistant to reduced aw, i.e. LAB, and then they may acquire a central role in the microbial events occurring in the product. Changes in consumers' habits have led to an increase of convenient LPFP with a relative long shelf-life (at least 3 weeks) which, on the other hand, may constitute a serious problem from a safety perspective since Listeria monocytogenes and sometimes Clostridium botulinum (mainly type E) may able to grow. In any case the LAB function in marine products is complex, depending on species, strains, interaction with other bacteria and the food matrix. They may have no particular effect or they may be responsible for spoilage and, in certain cases, they may even exert
Takeda, Shiro; Yamasaki, Keiko; Takeshita, Masahiko; Kikuchi, Yukiharu; Tsend-Ayush, Chuluunbat; Dashnyam, Bumbein; Ahhmed, Abdulatef M; Kawahara, Satoshi; Muguruma, Michio
2011-08-01
The aims of this study were to investigate the diversity of lactic acid bacteria (LAB) isolated from traditional Mongolian dairy products, and to estimate the probiotic potential of the isolated strains. We collected 66 samples of the traditional Mongolian dairy products tarag (n = 45), airag (n = 7), aaruul (n = 8), byasulag (n = 1) and eezgii (n = 5), from which 543 LAB strains were isolated and identified based on 16S ribosomal DNA sequence. The predominant species of those products were Lactobacillus (L.) delbrueckii ssp. bulgaricus, L. helveticus, L. fermentum, L. delbrueckii ssp. lactis and Lactococcus lactis ssp. lactis. However, we could not detect any LAB strains from eezgii. All LAB isolates were screened for tolerance to low pH and to bile acid, gas production from glucose, and adherence to Caco-2 cells. In vitro, we found 10 strains possess probiotic properties, and almost identified them as L. plantarum or L. paracasei subspecies, based on 16S ribosomal DNA and carbohydrate fermentation pattern. These strains were differentiated from each other individually by randomly amplified polymorphic DNA analysis. Additionally, it was notable that 6/10 strains were isolated from camel milk tarag from the Dornogovi province. 2011 The Authors. Animal Science Journal © 2011 Japanese Society of Animal Science.
Biodegradation of chlorobenzene by indigenous bacteria
DOE Office of Scientific and Technical Information (OSTI.GOV)
Nishino, S.F.; Spain, J.C.; Pettigrew, C.A.
Soil and ground water from four sites chronically contaminated with chlorobenzenes were examined to determine whether indigenous bacteria could degrade the contaminants and whether the addition of specific chlorobenzene-degrading bacteria enhanced the degradation rate. At each site, chlorobenzene-degrading bacteria were readily isolated from chlorobenzene-contaminated wells, whereas similar samples from noncontaminated wells yielded no chlorobenzene-degrading bacteria. Isolates were tested for growth on a variety of substrates. At a site contaminated with several solvents, a bioreactor was inoculated with the chlorobenzene-degrading Pseudomonas sp. strain JS150. Contaminated water was pumped through this bioreactor and a control bioreactor that had been colonized by inmore » indigenous microorganisms. The contaminants were removed from both bioreactors; however, JS150 could not be recovered from the inoculated bioreactor after three weeks of operation. A follow-up lab study using ground water from the contaminated site confirmed the field results. The authors conclude that chlorobenzene contamination of soil causes the development of indigenous degradative populations that have a competitive advantage over inoculated strains. The mechanism and time course of this acclimation are poorly understood and require additional study.« less
Selection of bacteriocin producer strains of lactic acid bacteria from a dairy environment.
Lasagno, M; Beoleito, V; Sesma, F; Raya, R; Font de Valdez, G; Eraso, A
2002-01-01
Two strains showing bacteriocin production were selected from a total of 206 lactic acid bacteria isolated from samples of milk, milk serum, whey and homemade cheeses in Southern Cordoba, Argentina. This property was detected by means of well diffusion assays. The strains were identified as Enterococcus hirae and Enterococcus durans. The protein nature of those substances was proved by showing their sensitivity to type IV and XXV proteases, papaine, trypsin, pepsin and K proteinase. The bacteriocins inhibited the growth of Listeria monocytogenes, Bacillus cereus, Clostridium perfringes and two strains of Staphylococcus aureus, an A-enterotoxin and a B-enterotoxin producers. All of these bacteria are common pathogens usually associated with food borne diseases (ETA). These lactic acid bacteria or their bacteriocins could be suitable candidates for food preservation and specially useful in the our regional dairy industry.
Genetic and Technological Characterisation of Vineyard- and Winery-Associated Lactic Acid Bacteria
Nisiotou, Aspasia A.; Filippousi, Maria-Evangelia; Fragkoulis, Petros; Tassou, Chryssoula; Banilas, Georgios
2015-01-01
Vineyard- and winery-associated lactic acid bacteria (LAB) from two major PDO regions in Greece, Peza and Nemea, were surveyed. LAB were isolated from grapes, fermenting musts, and winery tanks performing spontaneous malolactic fermentations (MLF). Higher population density and species richness were detected in Nemea than in Peza vineyards and on grapes than in fermenting musts. Pediococcus pentosaceus and Lactobacillus graminis were the most abundant LAB on grapes, while Lactobacillus plantarum dominated in fermenting musts from both regions. No particular structure of Lactobacillus plantarum populations according to the region of origin was observed, and strain distribution seems random. LAB species diversity in winery tanks differed significantly from that in vineyard samples, consisting principally of Oenococcus oeni. Different strains were analysed as per their enological characteristics and the ability to produce biogenic amines (BAs). Winery-associated species showed higher resistance to low pH, ethanol, SO2, and CuSO4 than vineyard-associated isolates. The frequency of BA-producing strains was relatively low but not negligible, considering that certain winery-associated Lactobacillus hilgardii strains were able to produce BAs. Present results show the necessity of controlling the MLF by selected starters in order to avoid BA accumulation in wine. PMID:25866789
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®
Galanis, Alex; Kourkoutas, Yiannis; Tassou, Chrysoula C.; Chorianopoulos, Nikos
2015-01-01
Lactobacillus plantarum 2035 and Lactobacillus plantarum ACA-DC 2640 are two lactic acid bacteria (LAB) strains that have been isolated from Feta cheese. Both display significant potential for the production of novel probiotic food products. The aim of the present study was the development of an accurate and efficient method for the molecular detection and identification of the above strains in a single reaction. A multiplex PCR assay was designed for each strain, based on specific primers derived from Random Amplified Polymorphic DNA (RAPD) Sequenced Characterized Amplified Region (SCAR) analysis. The specificity of the assay was tested with a total of 23 different LAB strains, for L. plantarum 2035 and L. plantarum ACA-DC 2640. The multiplex PCR assay was also successfully applied for the detection of the above cultures in yogurt samples prepared in our lab. The proposed methodology may be applied for monitoring the presence of these strains in food products, thus evaluating their probiotic character. Moreover, our strategy may be adapted for other novel LAB strains with probiotic potential, thus providing a powerful tool for molecular discrimination that could be invaluable to the food industry. PMID:26506345
Galanis, Alex; Kourkoutas, Yiannis; Tassou, Chrysoula C; Chorianopoulos, Nikos
2015-10-22
Lactobacillus plantarum 2035 and Lactobacillus plantarum ACA-DC 2640 are two lactic acid bacteria (LAB) strains that have been isolated from Feta cheese. Both display significant potential for the production of novel probiotic food products. The aim of the present study was the development of an accurate and efficient method for the molecular detection and identification of the above strains in a single reaction. A multiplex PCR assay was designed for each strain, based on specific primers derived from Random Amplified Polymorphic DNA (RAPD) Sequenced Characterized Amplified Region (SCAR) analysis. The specificity of the assay was tested with a total of 23 different LAB strains, for L. plantarum 2035 and L. plantarum ACA-DC 2640. The multiplex PCR assay was also successfully applied for the detection of the above cultures in yogurt samples prepared in our lab. The proposed methodology may be applied for monitoring the presence of these strains in food products, thus evaluating their probiotic character. Moreover, our strategy may be adapted for other novel LAB strains with probiotic potential, thus providing a powerful tool for molecular discrimination that could be invaluable to the food industry.
Bioconversion Using Lactic Acid Bacteria: Ginsenosides, GABA, and Phenolic Compounds.
Lee, Na-Kyoung; Paik, Hyun-Dong
2017-05-28
Lactic acid bacteria (LAB) are used as fermentation starters in vegetable and dairy products and influence the pH and flavors of foods. For many centuries, LAB have been used to manufacture fermented foods; therefore, they are generally regarded as safe. LAB produce various substances, such as lactic acid, β-glucosidase, and β-galactosidase, making them useful as fermentation starters. Existing functional substances have been assessed as fermentation substrates for better component bioavailability or other functions. Representative materials that were bioconverted using LAB have been reported and include minor ginsenosides, γ-aminobutyric acid, equol, aglycones, bioactive isoflavones, genistein, and daidzein, among others. Fermentation mainly involves polyphenol and polysaccharide substrates and is conducted using bacterial strains such as Streptococcus thermophilus, Lactobacillus plantarum, and Bifidobacterium sp. In this review, we summarize recent studies of bioconversion using LAB and discuss future directions for this field.
Yi, Young-Joo; Lim, Jeong-Muk; Gu, Suna; Lee, Wan-Kyu; Oh, Eunyoung; Lee, Sang-Myeong; Oh, Byung-Taek
2017-04-01
It has been demonstrated that certain lactic acid bacteria (LAB) can sequester metal ions by binding them to their surfaces. In the present study, lead (Pb)-resistant LAB were isolated from kimchi, a Korean fermented food. A total of 96 different LAB strains were isolated, and 52 strains showed lead resistance. Among them, an LAB strain-96 (L-96) identified as Leuconostoc mesenteroides showed remarkable Pb resistance and removal capacity. The maximum adsorption capacity of this strain calculated using the Langmuir isotherm was 60.6 mg Pb/g. In an in vivo experiment, young male mice were provided with water (A), Pb-water (B), or Pb-water+ L-96 (C) during puberty. Lower glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) levels in Pb-exposed male mice that received strain L-96 as a probiotic were suggestive of reduced hepatotoxicity. Moreover, feces from mice treated with L-96 contained more Pb than feces from untreated mice. Increased Pb elimination likely reduced internal accumulation, and this hypothesis was supported by significantly lower Pb concentrations in kidneys and testes of the mice treated with strain L-96. The motility and ATP content of epididymal spermatozoa were partially restored if strain L-96 was administered. In conclusion, isolated L-96 LAB had lead-biosorption activity and efficiently detoxified lead-poisoned male mice, resulting in recovering male reproductive function. These results suggest the potential use of LAB as a probiotic to protect humans from the adverse effects of Pb exposure.
The effect of lactic acid bacteria isolates on the urinary tract pathogens to infants in vitro.
Lim, In Seok; Lee, Ho Seok; Kim, Won Yong
2009-01-01
Urinary tract infections are common clinical problems in children, even though lots of treatment strategies have been tried. Many studies of the application of probiotics for urinary tract infection in female adults exist, but there is a lack of studies in children. The aims of this study were to screen probiotic strains for inhibiting the uropathogens in vitro, to find candidates for in vivo study. Nine strains of E. coli were isolated from children with urinary tract infection and six uropathogens were obtained from Korean Collection for Type Cultures and American Type Culture Collection. Also 135 lactic acid bacteria (LAB) strains were isolated from healthy children, and were identified through physiologic, biochemical methods, 16S rDNA PCR, and data analysis. And with agar disk diffusion assay technique the antimicrobial activities of these LAB strains against those uropathogens were examined. Three strains of separated LAB strains demonstrated major antimicrobial activity against all the uropathogens. In the agar disk diffusion assay technique, antimicrobial activities increased most in the 4th day culture broth with separated Lactobacillus. In summary, some LAB can be used as candidates to develop the probiotic microorganisms that inhibit uropathogens in children, and are expected to be applied to treatment and prevention of pediatric urinary tract infection.
Coaggregation between probiotic bacteria and caries-associated strains: an in vitro study.
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.
da Costa, Whyara Karoline Almeida; de Souza, Geany Targino; Brandão, Larissa Ramalho; de Lima, Rafael Cardoso; Garcia, Estefânia Fernandes; Dos Santos Lima, Marcos; de Souza, Evandro Leite; Saarela, Maria; Magnani, Marciane
2018-06-01
This study assessed the antagonistic activity of fruit-derived lactic acid bacteria (LAB) strains against food-related bacteria and the effects of the highest organic acids LAB producers on the survival of Listeria monocytogenes and Salmonella Enteritidis PT4 in cheese and chicken meat, respectively. The production of organic acids by the Lactobacillus strains in the tested food matrices was also monitored. All tested LAB strains showed antagonistic activity in vitro on the growth of pathogenic or spoiling food-related bacteria, particularly on L. monocytogenes and/or S. Enteritidis PT4, through the action of non-proteinaceous substances. The highest amounts of acetic and lactic acid were detected in cell free culture supernatants of L. paracasei 108 and L. plantarum 201. In "Minas Frescal" cheese, L. plantarum 49 and L. paracasei 108 decreased the counts of L. monocytogenes, and L. plantarum 201 showed bacteriostatic effects on this pathogen over time. L. paracasei 108 decreased the counts of S. Enteritidis PT4 in ground chicken breast; L. plantarum 49 and L. plantarum 201 failed to decrease the counts of this pathogen. Decreases in counts of L. monocytogenes or S. Enteritidis in "Minas Frescal" cheese and ground chicken breast, respectively, were related with increases in lactic and acetic acid contents and decreases in pH values. L. plantarum 49 and L. paracasei 108 could be used as biopreservation tools in cheese and chicken breast meat, respectively. Copyright © 2018. Published by Elsevier Ltd.
Inhibition of Staphylococcus aureus by crude and fractionated extract from lactic acid bacteria.
Wong, C-B; Khoo, B-Y; Sasidharan, S; Piyawattanametha, W; Kim, S H; Khemthongcharoen, N; Ang, M-Y; Chuah, L-O; Liong, M-T
2015-03-01
Increasing levels of antibiotic resistance by Staphylococcus aureus have posed a need to search for non-antibiotic alternatives. This study aimed to assess the inhibitory effects of crude and fractionated cell-free supernatants (CFS) of locally isolated lactic acid bacteria (LAB) against a clinical strain of S. aureus. A total of 42 LAB strains were isolated and identified from fresh vegetables, fresh fruits and fermented products prior to evaluation of inhibitory activities. CFS of LAB strains exhibiting a stronger inhibitive effect against S. aureus were fractionated into crude protein, polysaccharide and lipid fractions. Crude protein fractions showed greater inhibition against S. aureus compared to polysaccharide and lipid fractions, with a more prevalent effect from Lactobacillus plantarum 8513 and L. plantarum BT8513. Crude protein, polysaccharide and lipid fractions were also characterised with glycine, mannose and oleic acid being detected as the major component of each fraction, respectively. Scanning electron microscopy revealed roughed and wrinkled membrane morphology of S. aureus upon treatment with crude protein fractions of LAB, suggesting an inhibitory effect via the destruction of cellular membrane. This research illustrated the potential application of fractionated extracts from LAB to inhibit S. aureus for use in the food and health industry.
Diversity of Lactic Acid Bacteria Associated with Banana Fruits in Taiwan.
Chen, Yi-Sheng; Liao, Yu-Jou; Lan, Yi-Shan; Wu, Hui-Chung; Yanagida, Fujitoshi
2017-04-01
Banana is a popular fruit worldwide. The lactic acid bacteria (LAB) microflora in banana fruits has not been studied in detail. A total of 164 LAB were isolated from banana fruits in Taiwan. These isolates were initially divided into nine groups (r1 to r9) using restriction fragment length polymorphism analysis and 16S ribosomal DNA sequencing. Isolates belonging to Lactobacillus plantarum group were further divided into three additional groups using multiplex PCR assay targeting the recA gene. The most common bacterial genera found in banana fruits were Lactobacillus and Weissella. The distribution of LAB indicated that, in most cases, neighboring regions shared common strains, but there were still some differences between regions. On the basis of phylogenetic analysis of 16S rRNA, rpoA, and pheS gene sequences, two strains included in the genera Lactobacillus were identified as potential novel species or subspecies. In addition, a total 36 isolates were found to have bacteriocin-producing abilities. These results suggest that various LAB are associated with banana fruits in Taiwan. This is the first report describing the distribution and varieties of LAB associated with banana fruits. In addition, one potential novel LAB species was also found in this study.
Li, Qiang; Wang, Mengdi; Feng, Jun; Zhang, Wei; Wang, Yuanyuan; Gu, Yanyan; Song, Cunjiang; Wang, Shufang
2013-09-01
A 90 m(3) biological contact oxidation system in chemical factory was bioaugmented with three strains of indigenous salt-tolerant bacteria. These three strains were screened from contaminative soil in situ. Their activity of growth and degradation was investigated with lab-scale experiments. Their salt-tolerant mechanism was confirmed to be compatible-solutes strategy for moderately halophilic bacteria, with amino acid and betaine playing important roles. The running conditions of the system were recorded for 150 days. The indigenous bacteria had such high suitability that the reactor got steady rapidly and the removal of COD maintained above 90%. It was introduced that biofilm fragments in sedimentation tank were inversely flowed to each reaction tank, and quantitative PCR demonstrated that this process could successfully maintain the bacterial abundance in the reaction tanks. In addition, the T-RFLP revealed that bioaugmented strains dominated over others in the biofilm. Copyright © 2013 Elsevier Ltd. All rights reserved.
Mohd Adnan, Ahmad Faris; Tan, Irene K P
2007-05-01
Two traditional fermented food 'tapai' (fermented tapioca) and 'tempoyak' (fermented durian flesh), chilli puree and fresh goat's milk were used as sources for the isolation of lactic acid bacteria (LAB). A total of 126 isolates were obtained and by sequential screening for catalase activity and Gram-staining, 55 were determined to be LAB out of which 16 were established to be homofermentative by the gel plug test. Seven isolates were identified by use of the API 50CHL kit and two lactobacilli strains and one lactococci strain were selected to study their growth and lactic acid production profiles in a time course experiment. The lactobacilli strains, both isolated from 'tapai', produced higher amounts of cells and lactic acid from glucose as compared to the lactococci strain isolated from fresh goat's milk.
Sun, Z H; Liu, W J; Zhang, J C; Yu, J; Gao, W; Jiri, M; Menghe, B; Sun, T S; Zhang, H P
2010-05-01
Five samples of Airag and 20 of Tarag (both in Mongolia) were collected from scattered households. One hundred strains of lactic acid bacteria (LAB) were isolated and identified from these samples according to phenotypic characterization and 16S rRNA gene sequence analysis. Eighty-five isolates belonged to the genus Lactobacillus, 15 being classified as coccoid LAB. All isolates belonged to 5 genera and 11 to different species and subspecies. Lactobacillus (Lb.) helveticus was predominant population in Airag samples, Lb. fermentum and Lb. helveticus were the major LAB microflora in Tarag.
Detection of arc genes related with the ethyl carbamate precursors in wine lactic acid bacteria.
Araque, Isabel; Gil, Joana; Carreté, Ramon; Bordons, Albert; Reguant, Cristina
2009-03-11
Trace amounts of the carcinogen ethyl carbamate can appear in wine by the reaction of ethanol with compounds such as citrulline and carbamyl phosphate, which are produced from arginine degradation by some wine lactic acid bacteria (LAB). In this work, the presence of arc genes for the arginine-deiminase pathway was studied in several strains of different species of LAB. Their ability to degrade arginine was also studied. To detect the presence of arc genes, degenerate primers were designed from the alignment of protein sequences in already sequenced LAB. The usefulness of these degenerate primers has been proven by sequencing some of the amplified PCR fragments and searching for homologies with published sequences of the same species and related ones. Correlation was found between the presence of genes and the ability to degrade arginine. Degrading strains included all heterofermentative lactobacilli, Oenococcus oeni , Pediococcus pentosaceus , and some strains of Leuconostoc mesenteroides and Lactobacillus plantarum .
Ayeni, Anthony Opeyemi; Ruppitsch, Werner; Ayeni, Funmilola Abidemi
2018-03-14
Gastrointestinal infections are endemic in Nigeria and several factors contribute to their continual survival, including bacterial resistance to commonly used antibiotics. Nigerian yogurts do not include probiotics, and limited information is available about the antimicrobial properties of the fermenters in the yogurt against gastrointestinal pathogens. Therefore, the antimicrobial potentials of bacteria in Nigeria-produced yogurts against intestinal pathogens were investigated in this study. Viable counts of lactic acid bacteria (LAB) in 15 brands of yogurt were enumerated and the bacteria identified by partial sequencing of 16S rRNA gene. Susceptibility of the gastrointestinal pathogens (Salmonella, Shigella and E. coli ) to antibiotics by disc diffusion method, to viable LAB by the agar overlay method, and to the cell-free culture supernatant (CFCS) of the LAB were investigated. Co-culture analysis of LAB and pathogens were also done. Viable counts of 1.5 × 10 11 cfu/ml were observed in some yogurt samples. Two genera were identified: Lactobacillus (70.7%) and Acetobacter (29.3%). The Lactobacillus species reduced multidrug-resistant gastrointestinal pathogens by 4 to 5 log while the zones of inhibition ranged between 11 and 23. The Lactobacillus and Acetobacter strains examined displayed good activities against the multidrug-resistant tested pathogens. This is the first report of antimicrobial activities of acetic acid bacteria isolated from yogurt in Nigeria.
Exploring the Microbiota of Faba Bean: Functional Characterization of Lactic Acid Bacteria.
Verni, Michela; Wang, Changyin; Montemurro, Marco; De Angelis, Maria; Katina, Kati; Rizzello, Carlo G; Coda, Rossana
2017-01-01
This study investigated the metabolic traits of 27 lactic acid bacteria (LAB) strains belonging to different species, previously isolated from faba bean. The activities assayed, related to technological and nutritional improvement of fermented faba bean, included peptidases, β-glucosidase, phytase, as well as exopolysaccharides synthesis and antimicrobial properties. In addition, the bacteria performance as starter cultures during faba bean fermentation on proteolysis, antioxidant potential, and degradation of condensed tannins were assessed. Fermentative profiling showed that only 7 out of 27 strains were able to metabolize D-raffinose, particularly Leuc. mesenteroides I01 and I57. All strains of Pediococcus pentosaceus exerted high PepN activity and exhibited β-glucosidase activity higher than the median value of 0.015 U, while phytase activity was largely distributed among the different strains. All the weissellas, and in lower amount leuconostocs, showed ability to produce EPS from sucrose. None of the strains did not survive the simulated gastrointestinal tract with the exception of P. pentosaceus I56, I76, 147, I214, having a viability of 8-9 log CFU/ml at the end of the treatment. None of the strains showed antimicrobial activity toward Staphylococcus aureus , while eight strains of P. pentosaceus exhibited a strong inhibitory activity toward Escherichia coli and Listeria monocytogenes . Generally, the doughs fermented with pediococci exhibited high amount of total free amino acids, antioxidant activity, and condensed tannins degradation. These results allowed the identification of LAB biotypes as potential starter cultures for faba bean bioprocessing, aiming at the enhancement of faba bean use in novel food applications.
Exploring the Microbiota of Faba Bean: Functional Characterization of Lactic Acid Bacteria
Verni, Michela; Wang, Changyin; Montemurro, Marco; De Angelis, Maria; Katina, Kati; Rizzello, Carlo G.; Coda, Rossana
2017-01-01
This study investigated the metabolic traits of 27 lactic acid bacteria (LAB) strains belonging to different species, previously isolated from faba bean. The activities assayed, related to technological and nutritional improvement of fermented faba bean, included peptidases, β-glucosidase, phytase, as well as exopolysaccharides synthesis and antimicrobial properties. In addition, the bacteria performance as starter cultures during faba bean fermentation on proteolysis, antioxidant potential, and degradation of condensed tannins were assessed. Fermentative profiling showed that only 7 out of 27 strains were able to metabolize D-raffinose, particularly Leuc. mesenteroides I01 and I57. All strains of Pediococcus pentosaceus exerted high PepN activity and exhibited β-glucosidase activity higher than the median value of 0.015 U, while phytase activity was largely distributed among the different strains. All the weissellas, and in lower amount leuconostocs, showed ability to produce EPS from sucrose. None of the strains did not survive the simulated gastrointestinal tract with the exception of P. pentosaceus I56, I76, 147, I214, having a viability of 8–9 log CFU/ml at the end of the treatment. None of the strains showed antimicrobial activity toward Staphylococcus aureus, while eight strains of P. pentosaceus exhibited a strong inhibitory activity toward Escherichia coli and Listeria monocytogenes. Generally, the doughs fermented with pediococci exhibited high amount of total free amino acids, antioxidant activity, and condensed tannins degradation. These results allowed the identification of LAB biotypes as potential starter cultures for faba bean bioprocessing, aiming at the enhancement of faba bean use in novel food applications. PMID:29312174
Zolfagharian, Hossein; Mohajeri, Mohammad; Babaie, Mahdi
2016-09-01
Mellitine, a major component of bee venom (BV, Apis mellifera ), is more active against gram positive than gram negative bacteria. Moreover, BV has been reported to have multiple effects, including antibacterial, antivirus, and anti-inflammation effects, in various types of cells. In addition, wasp venom has been reported to have antibacterial properties. The aim of this study was to evaluate the antibacterial activity of BV against selected gram positive and gram negative bacterial strains of medical importance. This investigation was set up to evaluate the antibacterial activity of BV against six grams positive and gram negative bacteria, including Staphylococcus aureus ( S. aureus ), Salmonella typhimurium , Escherichia coli ( E. coli ) O157:H7, Pseudomonas aeruginosa , Burkholderia mallei and Burkholderia pseudomallei. Three concentrations of crude BV and standard antibiotic (gentamicin) disks as positive controls were tested by using the disc diffusion method. BV was found to have a significant antibacterial effect against E. coli , S. aureus , and Salmonella typhyimurium in all three concentrations tested. However, BV had no noticeable effect on other tested bacteria for any of the three doses tested. The results of the current study indicate that BV inhibits the growth and survival of bacterial strains and that BV can be used as a complementary antimicrobial agent against pathogenic bacteria. BV lacked the effective proteins necessary for it to exhibit antibacterial activity for some specific strains while being very effective against other specific strains. Thus, one may conclude, that Apis mellifera venom may have a specific mechanism that allows it to have an antibacterial effect on certain susceptible bacteria, but that mechanism is not well understood.
González-Arenzana, Lucía; Santamaría, Pilar; López, Rosa; Tenorio, Carmen; López-Alfaro, Isabel
2012-01-01
Ecology of the lactic acid bacteria (LAB) during alcoholic fermentation (AF) and spontaneous malolactic fermentation (MLF) of Tempranillo wines from four wineries of La Rioja has been studied analyzing the influence of the winemaking method, processing conditions, and geographical origin. Five different LAB species were isolated during AF, while, during MLF, only Oenococcus oeni was detected. Although the clonal diversity of O. oeni strains was moderate, mixed populations were observed, becoming at least one strain with distinct PFGE profile the main responsible for MLF. Neither the winemaking method nor the cellar situation was correlated with the LAB diversity. However, processing conditions influenced the total number of isolates and the percentage of each isolated species and strains. The winemaking method could cause that genotypes found in semicarbonic maceration did not appear in other wineries. Four genotypes of O. oeni were isolated in more than one of the rest wineries. These four together with other dominant strains might be included in a future selection process. PMID:22489202
A natural odor attraction between lactic acid bacteria and the nematode Caenorhabditis elegans.
Choi, Jae Im; Yoon, Kyoung-Hye; Subbammal Kalichamy, Saraswathi; Yoon, Sung-Sik; Il Lee, Jin
2016-03-01
Animal predators can track prey using their keen sense of smell. The bacteriovorous nematode Caenorhabditis elegans employs sensitive olfactory sensory neurons that express vertebrate-like odor receptors to locate bacteria. C. elegans displays odor-related behaviors such as attraction, aversion and adaptation, but the ecological significance of these behaviors is not known. Using a combination of food microbiology and genetics, we elucidate a possible predator-prey relationship between C. elegans and lactic acid bacteria (LAB) in rotting citrus fruit. LAB produces the volatile odor diacetyl as an oxidized by-product of fermentation in the presence of citrate. We show that C. elegans is attracted to LAB when grown on citrate media or Citrus medica L, commonly known as yuzu, a citrus fruit native to East Asia, and this attraction is mediated by the diacetyl odor receptor, ODR-10. We isolated a wild LAB strain and a wild C. elegans-related nematode from rotten yuzu, and demonstrate that the wild nematode was attracted to the diacetyl produced by LAB. These results not only identify an ecological function for a C. elegans olfactory behavior, but contribute to the growing understanding of ecological relationships between the microbial and metazoan worlds.
A natural odor attraction between lactic acid bacteria and the nematode Caenorhabditis elegans
Choi, Jae Im; Yoon, Kyoung-hye; Subbammal Kalichamy, Saraswathi; Yoon, Sung-Sik; Il Lee, Jin
2016-01-01
Animal predators can track prey using their keen sense of smell. The bacteriovorous nematode Caenorhabditis elegans employs sensitive olfactory sensory neurons that express vertebrate-like odor receptors to locate bacteria. C. elegans displays odor-related behaviors such as attraction, aversion and adaptation, but the ecological significance of these behaviors is not known. Using a combination of food microbiology and genetics, we elucidate a possible predator–prey relationship between C. elegans and lactic acid bacteria (LAB) in rotting citrus fruit. LAB produces the volatile odor diacetyl as an oxidized by-product of fermentation in the presence of citrate. We show that C. elegans is attracted to LAB when grown on citrate media or Citrus medica L, commonly known as yuzu, a citrus fruit native to East Asia, and this attraction is mediated by the diacetyl odor receptor, ODR-10. We isolated a wild LAB strain and a wild C. elegans-related nematode from rotten yuzu, and demonstrate that the wild nematode was attracted to the diacetyl produced by LAB. These results not only identify an ecological function for a C. elegans olfactory behavior, but contribute to the growing understanding of ecological relationships between the microbial and metazoan worlds. PMID:26241504
Wang, Siran; Yuan, Xianjun; Dong, Zhihao; Li, Junfeng; Shao, Tao
2017-11-01
Four lactic acid bacteria (LAB) strains isolated from straw silages on the Tibetan Plateau were characterized, and their effects on the fermentation quality of Italian ryegrass (Lolium multiflorum Lam.) at different temperatures (10°C, 15°C and 25°C) were studied. These LAB isolates were evaluated using the acids production ability test, morphological observation, Gram staining, physiological, biochemical and acid tolerance tests. All the isolates (M1, LM8, LO7 and LOG9) could grow at 5-20°C, pH 3.5-7.0 and NaCl (3.0%, 6.5%). Strains M1, LM8, LO7 and LOG9 were identified as Lactobacillus plantarum, L. coryniformis, Pediococcus pentosaceus and P. acidilactici, respectively, by sequencing 16S ribosomal DNA. The four isolates were added to Italian ryegrass for ensiling for 30 days at various temperatures. Compared with the corresponding control, inoculating with isolates M1, LM8 and LO7 could improve the silage quality of Italian ryegrass at low temperatures, indicated by significantly (P < 0.05) higher lactic acid (LA) contents and ratios of lactic acid/acetic acid (LA/AA), and significantly (P < 0.05) lower pH and ammonia nitrogen/total nitrogen (AN/TN). Compared with other isolates, LM8 performed better at 10°C and 15°C, indicated by the higher (P < 0.05) LA content and ratio of LA/AA, and the lower (P < 0.05) pH and AN/TN. © 2017 Japanese Society of Animal Science.
Davoodabadi, Abolfazl; Soltan Dallal, Mohammad Mehdi; Rahimi Foroushani, Abbas; Douraghi, Masoumeh; Sharifi Yazdi, Mohammad Kazem; Amin Harati, Farzaneh
2015-08-01
Lactobacilli are normal microflora of the gastrointestinal (GI) tract and are a heterogeneous group of lactic acid bacteria (LAB). Lactobacillus strains with Probiotic activity may have health Benefits for human. This study investigates the probiotic potential of Lactobacillus strains obtained from the feces of healthy infants and also explores antibacterial activity of Lactobacillus strains with probiotic potential against enteropathogenic bacteria. Fecal samples were collected from 95 healthy infants younger than 18 months. Two hundred and ninety Lactobacillus strains were isolated and assessed for probiotic potential properties including ability to survive in gastrointestinal conditions (pH 2.0, 0.3% oxgall), adherence to HT-29 cells and antibiotic resistance. Six strains including Lactobacillus fermentum (4 strains), Lactobacillus paracasei and Lactobacillus plantarum showed good probiotic potential and inhibited the growth of enteropathogenic bacteria including ETEC H10407, Shigella flexneri ATCC 12022, Shigella sonnei ATCC 9290, Salmonella enteritidis H7 and Yersinia enterocolitica ATCC 23715. These Lactobacillus strains with probiotic potential may be useful for prevention or treatment of diarrhea, but further in vitro and in vivo studies on these strains are still required. Copyright © 2015 Elsevier Ltd. All rights reserved.
Martínez, Patricio; Gálvez, Sebastián; Ohtsuka, Norimasa; Budinich, Marko; Cortés, María Paz; Serpell, Cristián; Nakahigashi, Kenji; Hirayama, Akiyoshi; Tomita, Masaru; Soga, Tomoyoshi; Martínez, Servet; Maass, Alejandro; Parada, Pilar
2013-02-01
In this study, we present the first metabolic profiles for two bioleaching bacteria using capillary electrophoresis coupled with mass spectrometry. The bacteria, Acidithiobacillus ferrooxidans strain Wenelen (DSM 16786) and Acidithiobacillus thiooxidans strain Licanantay (DSM 17318), were sampled at different growth phases and on different substrates: the former was grown with iron and sulfur, and the latter with sulfur and chalcopyrite. Metabolic profiles were scored from planktonic and sessile states. Spermidine was detected in intra- and extracellular samples for both strains, suggesting it has an important role in biofilm formation in the presence of solid substrate. The canonical pathway for spermidine synthesis seems absent as its upstream precursor, putrescine, was not present in samples. Glutathione, a catalytic activator of elemental sulfur, was identified as one of the most abundant metabolites in the intracellular space in A. thiooxidans strain Licanantay, confirming its participation in the sulfur oxidation pathway. Amino acid profiles varied according to the growth conditions and bioleaching species. Glutamic and aspartic acid were highly abundant in intra- and extracellular extracts. Both are constituents of the extracellular matrix, and have a probable role in cell detoxification. This novel metabolomic information validates previous knowledge from in silico metabolic reconstructions based on genomic sequences, and reveals important biomining functions such as biofilm formation, energy management and stress responses. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11306-012-0443-3) contains supplementary material, which is available to authorized users.
Screening of lactic acid bacteria from vacuum packaged beef for antimicrobial activity
Oliveira, Roseane B. P.; de L. Oliveira, Afonso; Glória, M. Beatriz A.
2008-01-01
The objective of this study was to isolate lactic acid bacteria (LAB) from vacuum packaged beef and to investigate their antagonist activity. LAB mean counts of 5.19 log cfu/cm2 were obtained from five samples of vacuum packaged beef. Two hundred isolates were selected and screened for the inhibitory effect on five ATCC reference Lactobacillus strains. Thirty six isolates showed activity in the agar spot test against at least two of the indicator strains. However, only six cell free supernatants (CFS) from these isolates exhibited activity against the indicator strains using the well-diffusion test and conditions that eliminated the effects of organic acids and hydrogen peroxide. L. acidophilus was the most sensitive indicator tested, whereas L. plantarum and L. fermentum were the most resistant ones. Identification by MIDI system indicated that these LAB isolates were Lactococcus lactis subsp. cremoris, Pediococcus acidilactici, Lactobacillus delbrueckii subsp. bulgaricus and Lactobacillus casei GC subgroup A. The antagonistic factors produced by most of these LAB against L. acidophilus were resistant to heat treatment (100°C for 10 min) and stable over a wide pH range (4.0 to 9.0). These data suggest that these isolates could be used as promising hurdles aiming increased safety and extended shelf life of meat products. PMID:24031232
Screening of species-specific lactic acid bacteria for veal calves multi-strain probiotic adjuncts.
Ripamonti, Barbara; Agazzi, Alessandro; Bersani, Carla; De Dea, Paola; Pecorini, Chiara; Pirani, Silvia; Rebucci, Raffaella; Savoini, Giovanni; Stella, Simone; Stenico, Alberta; Tirloni, Erica; Domeneghini, Cinzia
2011-06-01
The selection of promising specific species of lactic acid bacteria with potential probiotic characteristics is of particular interest in producing multi species-specific probiotic adjuncts in veal calves rearing. The aim of the present work was to select and evaluate in vitro the functional activity of lactic acid bacteria, Bifidobacterium longum and Bacillus coagulans strains isolated from veal calves in order to assess their potential use as multi species-specific probiotics for veal calves. For this purpose, bacterial strains isolated from faeces collected from 40 healthy 50-day-calves, were identified by RiboPrinter and 16s rRNA gene sequence. The most frequent strains belonged to the species B. longum, Streptococcus bovis, Lactobacillus animalis and Streptococcus macedonicus. Among these, 7 strains were chosen for testing their probiotic characteristics in vitro. Three strains, namely L. animalis SB310, Lactobacillus paracasei subsp. paracasei SB137 and B. coagulans SB117 showed varying individual but promising capabilities to survive in the gastrointestinal tract, to adhere, to produce antimicrobial compounds. These three selected species-specific bacteria demonstrated in vitro, both singularly and mixed, the functional properties needed for their use as potential probiotics in veal calves. Copyright © 2011 Elsevier Ltd. All rights reserved.
Sosa-Castañeda, J; Hernández-Mendoza, A; Astiazarán-García, H; Garcia, H S; Estrada-Montoya, M C; González-Córdova, A F; Vallejo-Cordoba, B
2015-10-01
Conjugated linoleic acid (CLA) has been shown to provide beneficial effects on health; however, the amount consumed in food is far from that required for the desired effects. Thus, increasing the CLA content in dairy foods through milk fermentation with specific lactic acid bacteria (LAB) offers an interesting alternative. Moreover, some LAB may be able to adhere to the intestinal mucosa and produce CLA through endogenous synthesis. Therefore, the objective of this study was to screen LAB isolates for their ability to produce CLA in skim milk and in simulated gastrointestinal conditions. Additionally, the ability of selected CLA-producing LAB to adhere to the intestinal mucosa in a murine model was assessed. Results showed that of 13 strains of Lactobacillus tested, only 4 were able to produce CLA in skim milk supplemented with linoleic acid (13.44 ± 0.78 to 50.9 ± 0.26 µg/mL). Furthermore, these 4 Lactobacillus strains were able to survive and produce CLA in simulated gastrointestinal conditions and to adhere to the intestinal mucosa of Wistar rats after 7 d of oral inoculation with fluorescently labeled bacteria. Accordingly, these 4 Lactobacillus strains may be used to manufacture fermented dairy foods to increase CLA content, and consumption of these fermented milks may result in CLA produced endogenously by these LAB. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
Evaluation of oral microbiology lab curriculum reform.
Nie, Min; Gao, Zhen Y; Wu, Xin Y; Jiang, Chen X; Du, Jia H
2015-12-07
According to the updated concept of oral microbiology, the School of Stomatology, Wuhan University, has carried out oral microbiology teaching reforms during the last 5 years. There was no lab curriculum before 2009 except for a theory course of oral microbiology. The school has implemented an innovative curriculum with oral medicine characteristics to strengthen understanding of knowledge, cultivate students' scientific interest and develop their potential, to cultivate the comprehensive ability of students. This study was designed to evaluate the oral microbiology lab curriculum by analyzing student performance and perceptions regarding the curriculum from 2009 to 2013. The lab curriculum adopted modalities for cooperative learning. Students collected dental plaque from each other and isolated the cariogenic bacteria with selective medium plates. Then they purified the enrichment culture medium and identified the cariogenic strains by Gram stain and biochemical tests. Both quantitative and qualitative data for 5 years were analysed in this study. Part One of the current study assessed student performance in the lab from 2009 to 2013. Part Two used qualitative means to assess students' perceptions by an open questionnaire. The 271 study students' grades on oral microbiology improved during the lab curriculum: "A" grades rose from 60.5 to 81.2 %, and "C" grades fell from 28.4 to 6.3 %. All students considered the lab curriculum to be interesting and helpful. Quantitative and qualitative data converge to suggest that the lab curriculum has strengthened students' grasp of important microbiology-related theory, cultivated their scientific interest, and developed their potential and comprehensive abilities. Our student performance and perception data support the continued use of the innovative teaching system. As an extension and complement of the theory course, the oral microbiology lab curriculum appears to improve the quality of oral medicine education and help to
Gomółka-Pawlicka, M; Uradziński, J
2003-01-01
The present study was aimed at determining the influence of 15 strains of lactic acid bacteria on the growth of 8 Yersinia enterocolitica strains in model set-ups, and in meat and ageing fermented sausages. The investigations were performed within the framework of three alternate stages which differed in respect to the products studied, the number of Lactobacillus sp. strains and, partly, methodological approach. The ratio between lactic acid bacteria and Yersinia enterocolitica strains studied was, depending on the variant of experiment, 1:1, 1:2 and 2:1, respectively. The study also considered water activity (aw) and pH of the products investigated. The results suggest that all the lactic acid bacteria strains used within the framework of the model set-ups had antagonistic effect on all the Salmonella sp. strains. However, this ability was not observed with respect to of tested lactic acid bacteria strains in meat and fermented sausage. This ability was possessed by one of the strains investigated--Lactobacillus helveticus T 78. The temperature and time of the incubation of sausages, but not aw and pH, were found to have a distinct influence on the antagonistic interaction between the bacteria tested.
Ünlü, Gülhan; Nielsen, Barbara; Ionita, Claudia
2015-12-01
One hundred and eight strains of lactic acid bacteria (LAB) were screened for bacteriocin production by the modified deferred antagonism and agar well diffusion methods. When the modified deferred antagonism method was employed, 82 LAB strains showed inhibitory action against Listeria monocytogenes v7 ½a, whereas 26 LAB strains expressed no inhibition. Only 12 LAB strains exhibited inhibitory activity when the agar well diffusion method was used, 11 of which had been previously recognized as bacteriocin production positive (Bac(+)). Lactobacillus viridescens NRRL B-1951 was determined, for the first time, to produce an inhibitory compound with a proteinaceous nature. The inhibitory activity was observed in the presence of lipase, α-chymotrypsin, and trypsin, but no inhibition zone could be detected in the presence of proteinase K, indicating the proteinaceous nature of the inhibitory compound. The inhibitory compound was active against Lact. sake ATCC 15521 and Lact. plantarum NCDO 995. Bacteriocin production by the Bac(+) LAB strains was assessed in Lactobacillus MRS Broth as well as in dairy-based media such as nonfat milk, demineralized whey powder, and cheddar cheese whey supplemented with complex nutrient sources that are rich in nitrogen. Lact. sake ATCC 15521 and L. monocytogenes CWD 1002, CWD 1092, CWD 1157, CWD 1198, and v7 ½a were used as indicators. The inhibitory activities of the bacteriocins varied depending on the indicator strains and the growth media used. The LAB indicator strains were found to be more sensitive to inhibition by bacteriocins when compared to the listerial indicator strains. Among the listerial indicators, L. monocytogenes CWD 1002 and CWD 1198 were the most sensitive strains to the bacteriocins investigated in this study. Media composition had a significant influence on bacteriocin production and activity. When compared to demineralized whey powder medium and cheddar cheese whey medium supplemented with whey protein concentrate
The inhibitory effects of wine phenolics on lysozyme activity against lactic acid bacteria.
Guzzo, F; Cappello, M S; Azzolini, M; Tosi, E; Zapparoli, G
2011-08-15
The lysozyme of hen's egg white is used in winemaking to control spontaneous lactic acid bacteria (LAB). A total of eight LAB strains, isolated from grape must and wine, were used to assess the inhibitory effects of wine phenolics on lysozyme activity. The presence of phenolics, extracted from grape pomace, in growth medium reduced the mortality rate due to the lysozyme activity. This effect was especially clear in the case of strains belonging to Lactobacillus uvarum, Pediococcus parvulus and Oenococccus oeni, which are more sensitive to lysozyme than L. plantarum and L. hilgardii strains. Cell lysis assays carried out on four strains sensitive to lysozyme and Micrococcus lysodeikticus ATCC 4698, used as a reference strain, confirmed the inhibition of grape pomace phenolics on the muramidase. There was no interference from non-flavonoids, flavanols and flavonol compounds, when they were tested individually, on the lysozyme activity against the strains. Anthocyanins extracted from grape skins slightly inhibited the activity only against M. lysodeikticus. However, proanthocyanidins extracted from seed berries, strongly inhibited the lysozyme. In this extract, dimers were the predominant oligomers of flavan-3-ol. The study demonstrated that the effectiveness of lysozyme against LAB in red winemaking is related to the amount of low molecular weight proanthocyanidins that are released when the grapes are macerating. Copyright © 2011 Elsevier B.V. All rights reserved.
Animal Rennets as Sources of Dairy Lactic Acid Bacteria
Cruciata, Margherita; Sannino, Ciro; Ercolini, Danilo; Scatassa, Maria L.; De Filippis, Francesca; Mancuso, Isabella; La Storia, Antonietta; Moschetti, Giancarlo
2014-01-01
The microbial composition of artisan and industrial animal rennet pastes was studied by using both culture-dependent and -independent approaches. Pyrosequencing targeting the 16S rRNA gene allowed to identify 361 operational taxonomic units (OTUs) to the genus/species level. Among lactic acid bacteria (LAB), Streptococcus thermophilus and some lactobacilli, mainly Lactobacillus crispatus and Lactobacillus reuteri, were the most abundant species, with differences among the samples. Twelve groups of microorganisms were targeted by viable plate counts revealing a dominance of mesophilic cocci. All rennets were able to acidify ultrahigh-temperature-processed (UHT) milk as shown by pH and total titratable acidity (TTA). Presumptive LAB isolated at the highest dilutions of acidified milks were phenotypically characterized, grouped, differentiated at the strain level by randomly amplified polymorphic DNA (RAPD)-PCR analysis, and subjected to 16S rRNA gene sequencing. Only 18 strains were clearly identified at the species level, as Enterococcus casseliflavus, Enterococcus faecium, Enterococcus faecalis, Enterococcus lactis, Lactobacillus delbrueckii, and Streptococcus thermophilus, while the other strains, all belonging to the genus Enterococcus, could not be allotted into any previously described species. The phylogenetic analysis showed that these strains might represent different unknown species. All strains were evaluated for their dairy technological performances. All isolates produced diacetyl, and 10 of them produced a rapid pH drop in milk, but only 3 isolates were also autolytic. This work showed that animal rennet pastes can be sources of LAB, mainly enterococci, that might contribute to the microbial diversity associated with dairy productions. PMID:24441167
Wang, Jing; Wei, Xinyuan; Fan, Mingtao
2018-06-01
The aim of this study was to evaluate the antibiotic susceptibility of lactic acid bacteria (LAB) and coagulase-negative staphylococci (CNS) strains isolated from naturally fermented smoked pork produced in Hunan, China. A total of 48 strains were isolated by selective medium and identified at the species level by 16S rRNA gene sequencing as follows: Staphylococcus carnosus (23), Lactobacillus plantarum (12), Lactobacillus brevis (10), Lactobacillus sakei (1), Weissella confusa (1), and Weissella cibaria (1). All strains were typed by RAPD-PCR, and their susceptibility to 15 antibiotics was determined and expressed as the minimum inhibitory concentration (MIC) using agar dilution method. High resistance to penicillin G, streptomycin, gentamycin, vancomycin, chloramphenicol, norfloxacin, ciprofloxacin, kanamycin, and neomycin was found among the isolates. All the strains were sensitive to ampicillin, while the susceptibility to tetracycline, oxytetracycline, erythromycin, lincomycin, and roxithromycin varied. The presence of relevant resistance genes was investigated by PCR and sequencing, with the following genes detected: str(A), str(B), tet(O), tet(M), ere(A), and catA. Eleven strains, including 3 S. carnosus, 6 L. plantarum, and 2 L. brevis, harbored more than 3 antibiotic resistance genes. Overall, multiple antibiotic resistance patterns were widely observed in LAB and S. carnosus strains isolated from Hunan smoked pork. Risk assessment should be carried out with regard to the safe use of LAB and CNS in food production. We evaluated the antibiotic resistance of lactic acid bacteria and coagulase-negative staphylococci strains isolated from Chinese naturally fermented smoked pork. Our results may provide important data on establishing breakpoint standards for LAB and CNS and evaluating the safety risk of these strains for commercial use. © 2018 Institute of Food Technologists®.
Rapid identification of dairy lactic acid bacteria by M13-generated, RAPD-PCR fingerprint databases.
Rossetti, Lia; Giraffa, Giorgio
2005-11-01
About a thousand lactic acid bacteria (LAB) isolated from dairy products, especially cheeses, were identified and typed by species-specific PCR and RAPD-PCR, respectively. RAPD-PCR profiles, which were obtained by using the M13 sequence as a primer, allowed us to implement a large database of different fingerprints, which were analysed by BioNumerics software. Cluster analysis of the combined RAPD-PCR fingerprinting profiles enabled us to implement a library, which is a collection of library units, which in turn is a selection of representative database entries. A library unit, in this case, can be considered to be a definable taxon. The strains belonged to 11 main RAPD-PCR fingerprinting library units identified as Lactobacillus casei/paracasei, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus helveticus, Lactobacillus delbrueckii, Lactobacillus fermentum, Lactobacillus brevis, Enterococcus faecium, Enterococcus faecalis, Streptococcus thermophilus and Lactococcus lactis. The possibility to routinely identify newly typed, bacterial isolates by consulting the library of the software was valued. The proposed method could be suggested to refine previous strain identifications, eliminate redundancy and dispose of a technologically useful LAB strain collection. The same approach could also be applied to identify LAB strains isolated from other food ecosystems.
Ni, Kuikui; Wang, Yanping; Li, Dongxia; Cai, Yimin; Pang, Huili
2015-01-01
There has been growing interest to develop forage rice as a new feed resource for livestock. This study was to characterize the natural population of lactic acid bacteria (LAB) and select potentially excellent strains for paddy rice silage preparation in China. One hundred and twenty-six strains were isolated and screened from paddy rice silage prepared using a small-scale fermentation system, and ninety-nine of these isolates were considered to be LAB based on their Gram-positive and catalase-negative morphology and the production of most of their metabolic products as lactic acid. These isolates were divided into eight groups (A-H) on the basis of their morphological and biochemical characteristics. The Group A to H strains were identified as Lactobacillus (L.) plantarum subsp. plantarum (species ratio: 8.1%), L. casei (5.1%), Leuconostoc (Ln.) pseudomesenteroides (11.1%), Pediococcus (P.) pentosaceus (24.2%), Enterococcus (E.) mundtii (12.1%), Lactococcus (Lc.) garvieae (15.2%), E. faecium (9.1%) and Lc. lactis subsp. lactis (15.2%) based on sequence analyses of their 16S rRNA and recA genes. P. pentosaceus was the most abundant member of the LAB population in the paddy rice silage. A selected strain, namely L. casei R 465, was found to be able to grow under low pH conditions and to improve the silage quality with low pH and a relatively high content of lactic acid. This study demonstrated that forage paddy rice silage contains abundant LAB species and its silage can be well preserved by inoculation with LAB, and that strain R 465 can be a potentially excellent inoculant for paddy rice silage.
Ni, Kuikui; Wang, Yanping; Li, Dongxia; Cai, Yimin; Pang, Huili
2015-01-01
There has been growing interest to develop forage rice as a new feed resource for livestock. This study was to characterize the natural population of lactic acid bacteria (LAB) and select potentially excellent strains for paddy rice silage preparation in China. One hundred and twenty-six strains were isolated and screened from paddy rice silage prepared using a small-scale fermentation system, and ninety-nine of these isolates were considered to be LAB based on their Gram-positive and catalase-negative morphology and the production of most of their metabolic products as lactic acid. These isolates were divided into eight groups (A-H) on the basis of their morphological and biochemical characteristics. The Group A to H strains were identified as Lactobacillus (L.) plantarum subsp. plantarum (species ratio: 8.1%), L. casei (5.1%), Leuconostoc (Ln.) pseudomesenteroides (11.1%), Pediococcus (P.) pentosaceus (24.2%), Enterococcus (E.) mundtii (12.1%), Lactococcus (Lc.) garvieae (15.2%), E. faecium (9.1%) and Lc. lactis subsp. lactis (15.2%) based on sequence analyses of their 16S rRNA and recA genes. P. pentosaceus was the most abundant member of the LAB population in the paddy rice silage. A selected strain, namely L. casei R 465, was found to be able to grow under low pH conditions and to improve the silage quality with low pH and a relatively high content of lactic acid. This study demonstrated that forage paddy rice silage contains abundant LAB species and its silage can be well preserved by inoculation with LAB, and that strain R 465 can be a potentially excellent inoculant for paddy rice silage. PMID:25803578
Chen, Yi-Sheng; Wu, Hui-Chung; Wang, Chiung-Mei; Lin, Chia-Chun; Chen, Yi-Ting; Jhong, Yu-Jyun; Yanagida, Fujitoshi
2013-03-01
Lactobacillus pobuzihii is a novel species which has been previously found in pobuzihi (fermented cummingcordia), a traditional fermented food in Taiwan. However, the lactic acid bacteria (LAB) microflora in pobuzihi has not been studied in detail. In this study, LAB from pobuzihi were isolated, identified, and characterized. A total of 196 LAB were isolated; 79 cultures were isolated from the sample collected from a manufacturing factory, 38 from pobuzihi samples collected from 4 different markets, and 79 from 2 fresh cummingcordia samples. These isolates were characterized phenotypically and then divided into eight groups (A to H) by restriction fragment length polymorphism analysis and sequencing of 16S ribosomal DNA. Lactobacillus plantarum was the most abundant LAB found in most samples during the fermentation of pobuzihi. On the other hand, Enterococcus casseliflavus and Weissella cibaria were, respectively, the major species found in the two fresh cummingcordia samples. A potential novel species or subspecies of lactococcal strain was found. In addition, seven L. plantarum and five W. cibaria strains showed inhibitory activity against the indicator strain Lactobacillus sakei JCM 1157(T). This is the first report describing the distribution and varieties of LAB existing in the pobuzihi during its fermentation process and the final product on the market.
Bouchard, Damien S; Seridan, Bianca; Saraoui, Taous; Rault, Lucie; Germon, Pierre; Gonzalez-Moreno, Candelaria; Nader-Macias, Fatima M E; Baud, Damien; François, Patrice; Chuat, Victoria; Chain, Florian; Langella, Philippe; Nicoli, Jacques; Le Loir, Yves; Even, Sergine
2015-01-01
Bovine mastitis is a costly disease in dairy cattle worldwide. As of yet, the control of bovine mastitis is mostly based on prevention by thorough hygienic procedures during milking. Additional strategies include vaccination and utilization of antibiotics. Despite these measures, mastitis is not fully under control, thus prompting the need for alternative strategies. The goal of this study was to isolate autochthonous lactic acid bacteria (LAB) from bovine mammary microbiota that exhibit beneficial properties that could be used for mastitis prevention and/or treatment. Sampling of the teat canal led to the isolation of 165 isolates, among which a selection of ten non-redundant LAB strains belonging to the genera Lactobacillus and Lactococcus were further characterized with regard to several properties: surface properties (hydrophobicity, autoaggregation); inhibition potential of three main mastitis pathogens, Staphylococcus aureus, Escherichia coli and Streptococcus uberis; colonization capacities of bovine mammary epithelial cells (bMEC); and immunomodulation properties. Three strains, Lactobacillus brevis 1595 and 1597 and Lactobacillus plantarum 1610, showed high colonization capacities and a medium surface hydrophobicity. These strains are good candidates to compete with pathogens for mammary gland colonization. Moreover, nine strains exhibited anti-inflammatory properties, as illustrated by the lower IL-8 secretion by E. coli-stimulated bMEC in the presence of these LAB. Full genome sequencing of five candidate strains allowed to check for undesirable genetic elements such as antibiotic resistance genes and to identify potential bacterial determinants involved in the beneficial properties. This large screening of beneficial properties while checking for undesirable genetic markers allowed the selection of promising candidate LAB strains from bovine mammary microbiota for the prevention and/or treatment of bovine mastitis.
Wang, Jia-nan; Shi, Yan-yun; Zheng, Li-yan; Wang, Zhe; Cai, Zhang; Liu, Jie
2015-06-01
Six petroleum-degrading strains were isolated from oil-contaminated soil at Dagang oil field and oil sewage on Bohai offshore drilling platform in Tianjin using enrichment culture and isolation method. The physiological biochemical test together with 16S rDNA sequencing analysis indicated that they belonged to Bacillus (S1, S2, S3, S4), Pseudomonas (W1) and Ochrobactrum (W2), respectively. The strain S3 had the maximum degradation rate of alkane (41.3%) and aromatic hydrocarbon (30.9%) among all isolated strains showing the better degradation efficiency by endogenous bacteria when compared to that by the exogenous bacteria. The four Bacillus strains were used to construct microbiome, thereafter subjected to petroleum degradation efficiency test and analyzed. The results showed that microbiome F3 consisting of S1 and S4 had the maximum degradation rates of alkane (50.5%) and aromatic hydrocarbon (54.0%), which were 69.9% and 156.1% higher than those by single bacterium, respectively. Furthermore, they were 22.1% and 74.6% respectively higher than those by the most optimal degradation bacterium S3. Microbiome F4 consisting of S2 and S3 had the minimum degradation rates of alkane (18.5%) and aromatic hydrocarbon (18.9%) which were 55.3% and 39.0% lower than the degradation rates of single bacterium, respectively. The results also demonstrated that there were both microbial synergy promotion and antagonism inhibition among bacteria of the same genus in the petroleum degradation period. Bacteria with close affinity in Bacillus genus displayed mainly promoted petroleum degradation effect.
Yang, Y; Latorre, J D; Khatri, B; Kwon, Y M; Kong, B W; Teague, K D; Graham, L E; Wolfenden, A D; Mahaffey, B D; Baxter, M; Hernandez-Velasco, X; Merino-Guzman, R; Hargis, B M; Tellez, G
2018-02-01
The present study evaluated the microbiological properties of three probiotic candidate strains of lactic acid bacteria (LAB) (128; 131; CE11_2), their effect on intestinal epithelial permeability, and their ability to reduce intestinal colonization of Salmonella Typhimurium (ST) individually or as a batch culture in neonatal turkey poults. Isolates were characterized morphologically and identified using 16S rRNA sequence analyses. Each isolate was evaluated for tolerance and resistance to acidic pH, high osmotic NaCl concentrations, and bile salts in broth medium. In vitro assessment of antimicrobial activity against different enteropathogenic bacteria was determined using an overlay technique. In vitro intestinal permeability was evaluated using a stressed Caco-2 cell culture assay treated with/without the probiotic candidates. The in vivo effect of the selected LAB strains on ST cecal colonization was determined in two independent trials with neonatal turkey poults. The results obtained in this study demonstrate the tolerance of LAB candidates to pH 3, a NaCl concentration of 6.5%, and high bile salts (0.6%). All strains evaluated exhibited in vitro antibacterial activity against Salmonella Enteritidis, ST, and Campylobacter jejuni. Candidates 128 and 131 exhibited a coccus morphology and were identified as Enterococcus faecium, and bacterial strain CE11_2 exhibited clusters of cocci-shaped cells and was identified as Pediococcus parvulus. All three candidate probiotics significantly (P < 0.05) increased transepithelial electrical resistance (TEER) in Caco-2 cells following a 3-h incubation period with hydrogen peroxide compared to control and blank groups. The combination of all three candidates as a batch culture exhibited significant efficacy in controlling intestinal colonization of ST in neonatal turkey poults. Evaluation of the combination of these selected LAB strains according to performance and intestinal health parameters of chickens and turkeys are
Wu, Qinglong; Shah, Nagendra P
2017-11-22
γ-Aminobutyric acid (GABA) and GABA-rich foods have shown anti-hypertensive and anti-depressant activities as the major functions in humans and animals. Hence, high GABA-producing lactic acid bacteria (LAB) could be used as functional starters for manufacturing novel fermented dairy foods. Glutamic acid decarboxylases (GADs) from LAB are highly conserved at the species level based on the phylogenetic tree of GADs from LAB. Moreover, two functionally distinct GADs and one intact gad operon were observed in all the completely sequenced Lactobacillus brevis strains suggesting its common capability to synthesize GABA. Difficulties and strategies for the manufacture of GABA-rich fermented dairy foods have been discussed and proposed, respectively. In addition, a genetic survey on the sequenced LAB strains demonstrated the absence of cell envelope proteinases in the majority of LAB including Lb. brevis, which diminishes their cell viabilities in milk environments due to their non-proteolytic nature. Thus, several strategies have been proposed to overcome the non-proteolytic nature of Lb. brevis in order to produce GABA-rich dairy foods.
Metabolic strategies of beer spoilage lactic acid bacteria in beer.
Geissler, Andreas J; Behr, Jürgen; von Kamp, Kristina; Vogel, Rudi F
2016-01-04
Beer contains only limited amounts of readily fermentable carbohydrates and amino acids. Beer spoilage lactic acid bacteria (LAB) have to come up with metabolic strategies in order to deal with selective nutrient content, high energy demand of hop tolerance mechanisms and a low pH. The metabolism of 26 LAB strains of 6 species and varying spoilage potentialwas investigated in order to define and compare their metabolic capabilities using multivariate statistics and outline possible metabolic strategies. Metabolic capabilities of beer spoilage LAB regarding carbohydrate and amino acids did not correlate with spoilage potential, but with fermentation type (heterofermentative/homofermentative) and species. A shift to mixed acid fermentation by homofermentative (hof) Pediococcus claussenii and Lactobacillus backii was observed as a specific feature of their growth in beer. For heterofermentative (hef) LAB a mostly versatile carbohydrate metabolism could be demonstrated, supplementing the known relevance of organic acids for their growth in beer. For hef LAB a distinct amino acid metabolism, resulting in biogenic amine production, was observed, presumably contributing to energy supply and pH homeostasis.
Ercolini, D; Moschetti, G; Blaiotta, G; Coppola, S
2001-03-01
Separation of amplified V3 region from 16S rDNA by denaturing gradient gel electrophoresis (DGGE) was tested as a tool for differentiation of lactic acid bacteria commonly isolated from food. Variable V3 regions of 21 reference strains and 34 wild strains referred to species belonging to the genera Pediococcus, Enterococcus, Lactococcus, Lactobacillus, Leuconostoc, Weissella, and Streptococcus were analyzed. DGGE profiles obtained were species-specific for most of the cultures tested. Moreover, it was possible to group the remaining LAB reference strains according to the migration of their 16S V3 region in the denaturing gel. The results are discussed with reference to their potential in the analysis of LAB communities in food, besides shedding light on taxonomic aspects.
NASA Astrophysics Data System (ADS)
Maryati, Yati; Susilowati, Agustine; Melanie, Hakiki; Lotulung, Puspa D.
2017-01-01
Broccoli (Brassica oleracea L. ssp.) has a relatively high nutrient content, especially as a source of vitamins, minerals and fiber and contain bioactive compounds that act as antioxidants. In order to increase the nutritional value and innovate new products, fermentation process involving rich-antioxidants lactic acid bacteria (LAB) was done. The aim of this study is to determine the content of bioactive components, such as total polyphenols, total acid and antioxidant activity of the mixed culture of LAB (L. bulgaricus, S. thermophulus, L. acidophilus, Bd. bifidum)-fermented broccoli extracts. Ratio of fermented broccoli extract and concentration of starter cultureLAB was varied in the range of 5, 10, 15 and 20% (v/v), and the alterations of characteristics of the fermented broccoli extract, before and after fermentation (0 and 24 hours), were evaluated. The results showed that fermentation functional beverage broccoli with different concentrations of LAB cultures affect the antioxidant activity, total polyphenols, total acid and total cell of LAB generated. The optimum conditions obtained for the highest antioxidant activity of 6.74%, at aculture concentration of 20% during fermentation time of 24 h with a pH value of 4.29, total sugar of 10.89%, total acids of 0.97%, total polyphenols of 0.076%, and total LAB of 13.02 + 0.05 log cfu /ml.
Ghahremani, Enayat; Mardani, Mahnaz; Rezapour, Sadegh
2015-03-01
Lactic acid bacteria (LAB) with proteolitic activity are used as aromatic and antibacterial substances, cholesterol reduces, bile salt hydrolyses, and probiotic. The aims of this project were to isolate and identify natural LAB flora involved in traditional fermentation in cheeses of Khoramabad city and also to survey their probiotic potential. In order to achieve this goal, LAB were isolated and characterized using phenotypic and genotypic methods (PCR-sequencing); in the next stage, they were analyzed lowering cholesterol medium, hydrolysis of the bile, resistance to bile-resistant PH acidic stomach. At the end of the study, 88 cocci and 3 bacill were found: 58 Enterococcus faecium, 16 Enterococcus hirae, 5 Lactococcus lactis, 3 Lactobacillus plantarum, and 9 undetermined. The probiotic results of the bacteria had effects on the reduction of cholesterol, resistance to stomach acid, had relative antibacterial effects, and some strains had effects on hydrolyzing the bile. For further identification, the PCR method and the application of 16s-DNA-ITS genes and its sequencing were found useful. This study showed that lactic acid bacteria in the traditional cheese of the Khorramabad city have relative probiotic effect and that these lactic acid bacteria in fermented milk are suitable.
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
Isolation and characterization of new strains of cholesterol-reducing bacteria from baboons.
Brinkley, A W; Gottesman, A R; Mott, G E
1982-01-01
We isolated and characterized nine new strains of cholesterol-reducing bacteria from feces and intestinal contents of baboons. Cholesterol-brain agar was used for the primary isolation, and subsequent biochemical tests were done in a lecithin-cholesterol broth containing plasmenylethanolamine and various substrates. All strains had similar colony and cell morphology, hydrolyzed the beta-glucosides esculin and amygdalin, metabolized pyruvate, and produced acetate and acetoin. Unlike previously reported strains, the nine new strains did not require cholesterol and an alkenyl ether lipid (e.g., plasmalogen) for growth; however, only two strains reduced cholesterol in the absence of the plasmalogen. These two strains also produced succinate as an end product. Carbohydrate fermentation was variable; some strains produced weak acid (pH 5.5 to 6.0) from only a few carbohydrates, whereas other strains produced strong acid reactions (pH less than or equal to 5.5) from a wide variety of carbohydrates.
Ma, Bing-cun; Yang, Xin; Wang, Hong-ning; Cao, Hai-peng; Xu, Peng-wei; Ding, Meng-die; Liu, Hui
2016-01-01
To obtain adhesive and safe lactic acid bacteria (LAB) strains for expressing heterologous antigens, we screened LAB inhabitants in intestine of Tibetan chickens by analyzing their adhesion and safety properties and the selected LAB was engineered to express heterologous antigen (UTEpi C-A) based on chromosomal integration strategy. We demonstrated that a new Lactobacillu salivarius TCMM17 strain is strongly adhesive to chicken intestinal epithelial cells, contains no endogenous plasmids, is susceptible to tested antimicrobials, and shows no toxicities. In order to examine the potential of TCMM17 strain as heterogenous antigen delivering vehicle, we introduced a UTEpi C-A expression cassette in its chromosome by constructing a non-replicative plasmid (pORI280-UUTEpi C-AD). The recombinant TCMM17 strain (∆TCMM17) stably was found to keep the gene cassette through 50 generations, and successfully displayed EpiC encoded by the cassette on its surface. This work provides a universal platform for development of novel oral vaccines and expression of further antigens of avian pathogens.
Grana Padano cheese whey starters: microbial composition and strain distribution.
Rossetti, Lia; Fornasari, Maria Emanuela; Gatti, Monica; Lazzi, Camilla; Neviani, Erasmo; Giraffa, Giorgio
2008-09-30
The aim of this work was to evaluate the species composition and the genotypic strain heterogeneity of dominant lactic acid bacteria (LAB) isolated from whey starter cultures used to manufacture Grana Padano cheese. Twenty-four Grana Padano cheese whey starters collected from dairies located over a wide geographic production area in the north of Italy were analyzed. Total thermophilic LAB streptococci and lactobacilli were quantified by agar plate counting. Population structure of the dominant and metabolically active LAB species present in the starters was profiled by reverse transcriptase, length heterogeneity-PCR (RT-LH-PCR), a culture-independent technique successfully applied to study whey starter ecosystems. The dominant bacterial species were Lactobacillus helveticus, Lactobacillus delbrueckii subsp. lactis, Streptococcus thermophilus, and Lactobacillus fermentum. Diversity in the species composition allowed the whey cultures to be grouped into four main typologies, the one containing L. helveticus, L. delbrueckii subsp. lactis, and S. thermophilus being the most frequent one (45% of the cultures analyzed), followed by that containing only the two lactobacilli (40%). Only a minor fraction of the cultures contained L. helveticus alone (4%) or all the four LAB species (11%). Five hundred and twelve strains were isolated from the 24 cultures and identified by M13-PCR fingerprinting coupled with 16S rRNA gene sequencing. Most of the strains were L. helveticus (190 strains; 37% of the total), L delbrueckii subsp. lactis (90 strains; 18%) and S. thermophilus (215 strains; 42%). This result was in good agreement with the qualitative whey starter composition observed by RT-LH-PCR. M13-PCR fingerprinting indicated a markedly low infra-species diversity, i.e. the same biotypes were often found in more than one culture. The distribution of the biotypes into the different cultures was mainly dairy plant-specific rather than correlated with the different production areas.
Yu, J; Wang, H M; Zha, M S; Qing, Y T; Bai, N; Ren, Y; Xi, X X; Liu, W J; Menghe, B L G; Zhang, H P
2015-08-01
Russian traditional fermented dairy foods have been consumed for thousands of years. However, little research has focused on exploiting lactic acid bacteria (LAB) resources and analyzing the LAB composition of Russian traditional fermented dairy foods. In the present study, we cultured LAB isolated from fermented mare and cow milks, sour cream, and cheese collected from Kalmykiya, Buryats, and Tuva regions of Russia. Seven lactobacillus species and the Bifidobacterium genus were quantified by quantitative PCR. The LAB counts in these samples ranged from 3.18 to 9.77 log cfu/mL (or per gram). In total, 599 LAB strains were obtained from these samples using de Man, Rogosa, and Sharpe agar and M17 agar. The identified LAB belonged to 7 genera and 30 species by 16S rRNA and murE gene sequencing and multiplex PCR assay. The predominant LAB isolates were Lactobacillus helveticus (176 strains) and Lactobacillus plantarum (63 strains), which represented 39.9% of all isolates. The quantitative PCR results revealed that counts of 7 lactobacilli species and Bifidobacterium spp. of 30 fermented cow milk samples ranged from 1.19±0.34 (Lactobacillus helveticus in Tuva) to 8.09±0.71 (Lactobacillus acidophilus in Kalmykiya) log cfu/mL of fermented cow milk (mean ± standard error). The numbers of Bifidobacterium spp., Lb. plantarum, Lb. helveticus, and Lb. acidophilus revealed no significant difference between the 3 regions; nevertheless, Lactobacillus paracasei, Lactobacillus fermentum, Lactobacillus sakei, and Lactobacillus delbrueckii ssp. bulgaricus exhibited different degrees of variation across 3 regions. The results demonstrate that traditional fermented dairy products from different regions of Russia have complex compositions of LAB species. The diversity of LAB might be related to the type of fermented dairy product, geographical origin, and manufacturing process. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
Tsai, Cheng-Chih; Lai, Tzu-Min; Lin, Pei-Pei; Hsieh, You-Miin
2018-06-01
Urinary tract infections (UTIs) are the most common infectious diseases in infants and the elderly; they are also the most common among nosocomial infections. The treatment of UTIs usually involves a short-term course of antibiotics. The purpose of this study was to identify the strains of lactic acid bacteria (LAB) that can inhibit the urinary tract pathogen Staphylococcus saprophyticus, as alternatives to antibiotics. In this study, we collected 370 LAB strains from fermented plant products and reference strains from the Bioresources Collection and Research Center (BCRC). Using spent culture supernatants (SCS), we then screened these LAB strains with for antimicrobial effects on urinary tract pathogens by the well-diffusion assay. Seven LAB strains-PM2, PM68, PM78, PM201, PM206, PM229, and RY2-exhibited inhibitory activity and were evaluated for anti-growth activity against urinary tract pathogens by the co-culture inhibition assay. Anti-adhesion and anti-invasion activities against urinary tract pathogens were evaluated using the SV-HUC-1 urothelial cell cultures. The results revealed that the survival rate of S. saprophyticus ranged from 0.9-2.96%, with the pH continuously decreasing after co-culture with LAB strains for 4 h. In the competitive adhesion assay, the exclusion and competition groups performed better than the displacement group. In the SV-HUC-1 cell invasion assay, PM201, PM206, PM229, and RY2 were found to inhibit the invasion of SV-HUC-1 cells by S. saprophyticus BCRC 10786. To conclude, RY2, PM229, and PM68 strains exhibited inhibitory activity against the urinary tract pathogen S. saprophyticus.
Metabolic engineering of strains: from industrial-scale to lab-scale chemical production.
Sun, Jie; Alper, Hal S
2015-03-01
A plethora of successful metabolic engineering case studies have been published over the past several decades. Here, we highlight a collection of microbially produced chemicals using a historical framework, starting with titers ranging from industrial scale (more than 50 g/L), to medium-scale (5-50 g/L), and lab-scale (0-5 g/L). Although engineered Escherichia coli and Saccharomyces cerevisiae emerge as prominent hosts in the literature as a result of well-developed genetic engineering tools, several novel native-producing strains are gaining attention. This review catalogs the current progress of metabolic engineering towards production of compounds such as acids, alcohols, amino acids, natural organic compounds, and others.
Liu, Aiping; Li, Xiaoyan; Pu, Biao; Ao, Xiaolin; Zhou, Kang; He, Li; Chen, Shujuan; Liu, Shuliang
2017-03-29
To improve the quality of Chinese traditional Paocai, two psychrotolerant lactic acid bacteria (LAB) strains were isolated from Paocai, and the quality of Chinese Paocai product using these two strains as starter cultures was compared to a control sample fermented with aged brine at 10 °C. The results suggested that the physicochemical and sensory features of Paocai fermented with psychrotolerant LAB were more suitable for industrial applications. The nitrite content of Paocai fermented with psychrotolerant LAB was 1 mg/kg, which was significantly lower than that of the control Paocai (P < 0.05). Low-temperature fermentation with the starter cultures of psychrotolerant LAB could effectively prevent overacidity and over-ripening of the Paocai products. Additionally, Paocai fermented with psychrotolerant LAB harbored relatively simple microbial flora as revealed by polymerase chain reaction-denaturing gradient gel electrophoresis. This study provides a basis for improving the quality of Chinese traditional Paocai and the large-scale production of low-temperature Chinese traditional Paocai products.
Chen, Hsi-Chia; Wang, Sheng-Yao; Chen, Ming-Ju
2008-05-01
Lactic acid bacteria (LAB) in different original kefir grains were first assessed using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) by a culture-dependent way, and were further confirmed by DNA sequencing techniques. Results indicated that a combined method of cultivation with PCR-DGGE and subsequent DNA sequencing could successfully identify four LAB strains from three kefir grains from Taiwan (named Hsinchu, Mongolia and Ilan). Lactobacillus kefiri accounted, in the three kefir grains, for at least half of the isolated colonies while Lb. kefiranofaciens was the second most frequently isolated species. Leuconostoc mesenteroides was less frequently found but still in the three kefir grains conversely to Lactococcus lactis which based on culture-dependent isolation was only found in two of the kefir grains. It was interesting to find that all three kefir grains contain similar LAB species. Furthermore, the DGGE as a culture-independent method was also applied to detect the LAB strains. Results indicated that Lb. kefiranofaciens was found in all three kefir grains, whereas Lb. kefiri was only observed in Hsinchu kefir grain and Lc. lactis was found in both Mongolia and Ilan samples. Two additional strains, Pseudomonas spp. and E. coli, were also detected in kefir grains.
Evidence of Two Functionally Distinct Ornithine Decarboxylation Systems in Lactic Acid Bacteria
Romano, Andrea; Trip, Hein; Lonvaud-Funel, Aline; Lolkema, Juke S.
2012-01-01
Biogenic amines are low-molecular-weight organic bases whose presence in food can result in health problems. The biosynthesis of biogenic amines in fermented foods mostly proceeds through amino acid decarboxylation carried out by lactic acid bacteria (LAB), but not all systems leading to biogenic amine production by LAB have been thoroughly characterized. Here, putative ornithine decarboxylation pathways consisting of a putative ornithine decarboxylase and an amino acid transporter were identified in LAB by strain collection screening and database searches. The decarboxylases were produced in heterologous hosts and purified and characterized in vitro, whereas transporters were heterologously expressed in Lactococcus lactis and functionally characterized in vivo. Amino acid decarboxylation by whole cells of the original hosts was determined as well. We concluded that two distinct types of ornithine decarboxylation systems exist in LAB. One is composed of an ornithine decarboxylase coupled to an ornithine/putrescine transmembrane exchanger. Their combined activities results in the extracellular release of putrescine. This typical amino acid decarboxylation system is present in only a few LAB strains and may contribute to metabolic energy production and/or pH homeostasis. The second system is widespread among LAB. It is composed of a decarboxylase active on ornithine and l-2,4-diaminobutyric acid (DABA) and a transporter that mediates unidirectional transport of ornithine into the cytoplasm. Diamines that result from this second system are retained within the cytosol. PMID:22247134
Tang, Y; Saris, P E J
2013-10-01
Lactobacillus acidophilus LAB20 has potential to be a probiotic strain because it can be present at high numbers in the jejunum of dog. To specifically detect LAB20 from dog faecal samples, a real-time PCR protocol was developed targeting the novel surface (S) layer protein gene of LAB20. The presence of S-layer protein was verified by N-terminal sequencing of the approximately 50-kDa major band from SDS-PAGE gel. The corresponding S-layer gene was amplified by inverse PCR using homology to known S-layers and sequenced. This novel S-layer protein has low sequence similarity to other S-layer proteins in the N-terminal region (32-211 aa, 7-39%). This enabled designing strain-specific PCR primers. The primer set was utilized to study intestinal persistence of LAB20 in dog that was fed with LAB20 fermented milk for 5 days. The results showed that LAB20 can be detected from dog faecal sample after 6 weeks with 10(4·53) DNA copies g(-1) postadministration. It suggested that LAB20 could be a good candidate to study the mechanism behind its persistence and dominance in dog intestine and maybe utilize it as a probiotic for canine. A real-time PCR method was developed to detect Lactobacillus acidophilus LAB20, a strain that was previously found dominant in canine gastrointestinal (GI) tract. The quantitative detection was based on targeting to variation region of a novel S-layer protein found in LAB20, allowing to specifically enumerate LAB20 from dog faeces. The results showed that the real-time PCR method was sensitive enough to be used in later intervention studies. Interestingly, LAB20 was found to persist in dog GI tract for 6 weeks. Therefore, LAB20 could be a good candidate to study its colonization and potentially utilize as a canine probiotic. © 2013 The Society for Applied Microbiology.
Enhanced mucosal delivery of antigen with cell wall mutants of lactic acid bacteria.
Grangette, Corinne; Müller-Alouf, Heide; Hols, Pascal; Goudercourt, Denise; Delcour, Jean; Turneer, Mireille; Mercenier, Annick
2004-05-01
The potential of recombinant lactic acid bacteria (LAB) to deliver heterologous antigens to the immune system and to induce protective immunity has been best demonstrated by using the C subunit of tetanus toxin (TTFC) as a model antigen. Two types of LAB carriers have mainly been used, Lactobacillus plantarum and Lactococcus lactis, which differ substantially in their abilities to resist passage through the stomach and to persist in the mouse gastrointestinal tract. Here we analyzed the effect of a deficiency in alanine racemase, an enzyme that participates in cell wall synthesis, in each of these bacterial carriers. Recombinant wild-type and mutant strains of L. plantarum NCIMB8826 and L. lactis MG1363 producing TTFC intracellularly were constructed and used in mouse immunization experiments. Remarkably, we observed that the two cell wall mutant strains were far more immunogenic than their wild-type counterparts when the intragastric route was used. However, intestinal TTFC-specific immunoglobulin A was induced only after immunization with the recombinant L. plantarum mutant strain. Moreover, the alanine racemase mutant of either LAB strain allowed induction of a much stronger serum TTFC-specific immune response after immunization via the vagina, which is a quite different ecosystem than the gastrointestinal tract. The design and use of these mutants thus resulted in a major improvement in the mucosal delivery of antigens exhibiting vaccine properties.
NASA Astrophysics Data System (ADS)
Kiti, A. A.; Jamilah, I.; Rusmarilin, H.
2017-09-01
Lactic acid bacteria (LAB) is one group of microbes that has many benefits, notably in food and health industries sector. LAB plays an important role in food fermentation and it has bacteriostatic effect against the growth of pathogenic microorganisms. The research related LAB continued to be done to increase the diversity of potential isolates derived from nature which is indigenous bacteria for biotechnological purposes. This study was aimed to isolate and characterize LAB derived from pliek u sample and to examine the potency to inhibits Escherichia coli ATCC 25922 bacteria growth. A total of 5 isolates were isolated and based on morphological and physiological characteristics of the fifth bacteria, they are allegedly belonging to the genus Bacillus. Result of antagonistic test showed that the five isolates could inhibits the growth of E. coli ATCC 25922. The highest inhibition zone is 8.5 mm was shown by isolates NQ2, while the lowest inhibition is 1.5 mm was shown by isolates NQ3.
Lactic acid bacteria in dried vegetables and spices.
Säde, Elina; Lassila, Elisa; Björkroth, Johanna
2016-02-01
Spices and dried vegetable seasonings are potential sources of bacterial contamination for foods. However, little is known about lactic acid bacteria (LAB) in spices and dried vegetables, even though certain LAB may cause food spoilage. In this study, we enumerated LAB in 104 spices and dried vegetables products aimed for the food manufacturing industry. The products were obtained from a spice wholesaler operating in Finland, and were sampled during a one-year period. We picked isolates (n = 343) for species identification based on numerical analysis of their ribotyping patterns and comparing them with the corresponding patterns of LAB type strains. We found LAB at levels >2 log CFU/g in 68 (65%) of the samples, with the highest counts detected from dried onion products and garlic powder with counts ranging from 4.24 to 6.64 log CFU/g. The LAB identified were predominantly Weissella spp. (61%) and Pediococcus spp. (15%) with Weissella confusa, Weissella cibaria, Weissella paramesenteroides, Pediococcus acidilactici and Pediococcus pentosaceus being the species identified. Other species identified belonged to the genera of Enterococcus spp. (8%), Leuconostoc spp. (6%) and Lactobacillus spp. (2%). Among the LAB identified, Leuconostoc citreum, Leuconostoc mesenteroides and W. confusa have been associated with food spoilage. Our findings suggest that spices and dried vegetables are potential sources of LAB contamination in the food industry. Copyright © 2015 Elsevier Ltd. All rights reserved.
do Vale Pereira, G; da Cunha, D G; Pedreira Mourino, J L; Rodiles, A; Jaramillo-Torres, A; Merrifield, D L
2017-11-01
The aim of this study was to determine the intestinal microbiota of pirarucu (Arapaima gigas) in different growth stages (adult and fingerlings) and to isolate and identify potential probiotic bacteria. High-throughput sequencing analysis of the intestinal contents revealed that the majority of sequences belonged to the Proteobacteria, Fusobacteria and Firmicutes phyla. At the genus level, the greatest number of sequences belonged to Bradyrhizobium in adult fish, while Cetobacterium was the most abundant in juvenile fish. Twenty-three lactic-acid bacteria (LABs) were isolated on MRS agar from healthy juvenile fish. The isolates were tested in vitro for probiotic properties. Two isolates (identified as strains of Lactococcus lactis subsp. lactis and Enterococcus faecium) displayed antagonism against all 10 pathogens tested, were nonhaemolytic and maintained good viability for at least 3 weeks when supplemented to fish diets. The presence of a number of antibiotic resistance genes (ARGs), conferring resistance to erythromycin, tetracycline and chloramphenicol, was investigated by PCR. The absence of ARGs investigated the potential to antagonize pathogens, and favourable growth and survival characteristics indicate that these autochthonous isolates have the potential to be considered probiotics, which will be studied in future in vivo experiments. This study has demonstrated, for the first time, the normal microbiota in the A. gigas intestine during different life stages and the presence of LAB strains. It also demonstrated LAB antibiotic resistance and antagonistic behaviour against pathogens isolated from the same fish. © 2017 The Society for Applied Microbiology.
Predominant effect of host genetics on levels of Lactobacillus johnsonii bacteria in the mouse gut.
Buhnik-Rosenblau, Keren; Danin-Poleg, Yael; Kashi, Yechezkel
2011-09-01
The gut microbiota is strongly associated with the well-being of the host. Its composition is affected by environmental factors, such as food and maternal inoculation, while the relative impact of the host's genetics have been recently uncovered. Here, we studied the effect of the host genetic background on the composition of intestinal bacteria in a murine model, focusing on lactic acid bacteria (LAB) as an important group that includes many probiotic strains. Based on 16S rRNA gene genotyping, variation was observed in fecal LAB populations of BALB/c and C57BL/6J mouse lines. Lactobacillus johnsonii, a potentially probiotic bacterium, appeared at significantly higher levels in C57BL/6J versus BALB/c mouse feces. In the BALB/c gut, the L. johnsonii level decreased rapidly after oral administration, suggesting that some selective force does not allow its persistence at higher levels. The genetic inheritance of L. johnsonii levels was further tested in reciprocal crosses between the two mouse lines. The resultant F1 offspring presented similar L. johnsonii levels, confirming that mouse genetics plays a major role in determining these levels compared to the smaller maternal effect. Our findings suggest that mouse genetics has a major effect on the composition of the LAB population in general and on the persistence of L. johnsonii in the gut in particular. Concentrating on a narrow spectrum of culturable LAB enables the isolation and characterization of such potentially probiotic bacterial strains, which might be specifically oriented to the genetic background of the host as part of a personalized-medicine approach.
Sakaridis, I; Soultos, N; Dovas, C I; Papavergou, E; Ambrosiadis, I; Koidis, P
2012-02-01
This study was conducted to isolate psychrotrophic lactic acid bacteria (LAB) from chicken carcasses with inhibitory activity against strains of Salmonella spp. and Listeria monocytogenes. A total of 100 broiler samples were examined for the presence of LAB. Ninety-two LAB isolates that showed antimicrobial effects against Salmonella spp. and L. monocytogenes were further analysed to examine their LAB (Gram-positive, catalase negative, oxidase negative) and psychrotrophic characteristics (ability to grow at 7 °C). Fifty isolates were further selected and identified initially using standard biochemical tests in miniature (Micro-kits API CH 50) and then by sequencing of the 16s-23s rRNA gene boundary region (Intergenic Spacer Region). By molecular identification, these isolates were classified into 5 different LAB species: Lactobacillus salivarius, Lactobacillus reuteri, Lactobacillus johnsonii, Pediococcus acidilactici, and Lactobacillus paralimentarius. None of the isolates produced tyramine or histamine. Copyright © 2011 Elsevier Ltd. All rights reserved.
Vinderola, Gabriel; Matar, Chantal; Perdigon, Gabriela
2005-01-01
The mechanisms by which probiotic bacteria exert their effects on the immune system are not completely understood, but the epithelium may be a crucial player in the orchestration of the effects induced. In a previous work, we observed that some orally administered strains of lactic acid bacteria (LAB) increased the number of immunoglobulin A (IgA)-producing cells in the small intestine without a concomitant increase in the CD4+ T-cell population, indicating that some LAB strains induce clonal expansion only of B cells triggered to produce IgA. The present work aimed to study the cytokines induced by the interaction of probiotic LAB with murine intestinal epithelial cells (IEC) in healthy animals. We focused our investigation mainly on the secretion of interleukin 6 (IL-6) necessary for the clonal expansion of B cells previously observed with probiotic bacteria. The role of Toll-like receptors (TLRs) in such interaction was also addressed. The cytokines released by primary cultures of IEC in animals fed with Lactobacillus casei CRL 431 or Lactobacillus helveticus R389 were determined. Cytokines were also determined in the supernatants of primary cultures of IEC of unfed animals challenged with different concentrations of viable or nonviable lactobacilli and Escherichia coli, previously blocked or not with anti-TLR2 and anti-TLR4. We concluded that the small intestine is the place where a major distinction would occur between probiotic LAB and pathogens. This distinction comprises the type of cytokines released and the magnitude of the response, cutting across the line that separates IL-6 necessary for B-cell differentiation, which was the case with probiotic lactobacilli, from inflammatory levels of IL-6 for pathogens. PMID:16148174
Use of an acidophilic yeast strain to enable the growth of leaching bacteria on solid media.
Ngom, Baba; Liang, Yili; Liu, Yi; Yin, Huaqun; Liu, Xueduan
2015-03-01
In this study, a Candida digboiensis strain was isolated from a heap leaching plant in Zambia and used in double-layer agar plate to efficiently isolate and purify leaching bacteria. Unlike Acidiphilium sp., the yeast strain was tetrathionate tolerant and could metabolize a great range of organic compounds including organic acids. These properties allowed the yeast strain to enable and fasten the growth of iron and sulfur oxidizers on double-layer agar plate. The isolates were identified as Acidithiobacillus ferrooxidans FOX1, Leptospirillun ferriphilum BN, and Acidithiobacillus thiooxidans ZMB. These three leaching bacteria were inhibited by organic acids such as acetic and propionic acids; however, their activities were enhanced by Candida digboiensis NB under dissolved organic matter stress.
Yang, En; Fan, Lihua; Yan, Jinping; Jiang, Yueming; Doucette, Craig; Fillmore, Sherry; Walker, Bradley
2018-01-24
There has been continued interest in bacteriocins research from an applied perspective as bacteriocins have potential to be used as natural preservative. Four bacteriocinogenic lactic acid bacteria (LAB) strains of Lactobacillus curvatus (Arla-10), Enterococcus faecium (JFR-1), Lactobacillus paracasei subsp. paracasei (JFR-5) and Streptococcus thermophilus (TSB-8) were previously isolated and identified in our lab. The objective of this study was to determine the optimal growth conditions for both LAB growth and bacteriocins production. In this study, various growth conditions including culture media (MRS and BHI), initial pH of culture media (4.5, 5.5, 6.2, 7.4 and 8.5), and incubation temperatures (20, 37 and 44 °C) were investigated for LAB growth measured as optical density (OD), bacteriocin activity determined as arbitrary unit and viability of LAB expressed as log CFU ml -1 . Growth curves of the bacteriocinogenic LAB were generated using a Bioscreen C. Our results indicated that Arla-10, JFR-1, and JFR-5 strains grew well on both MRS and BHI media at growth temperature tested whereas TSB-8 strain, unable to grow at 20 °C. LAB growth was significantly affected by the initial pH of culture media (p < 0.001) and the optimal pH was found ranging from 6.2 to 8.5. Bacteriocin activity was significantly different in MRS versus BHI (p < 0.001), and the optimal condition for LAB to produce bacteriocins was determined in MRS broth, pH 6.2 at 37 °C. This study provides useful information on potential application of bacteriocinogenic LAB in food fermentation processes.
Ennahar, Saïd; Cai, Yimin; Fujita, Yasuhito
2003-01-01
A total of 161 low-G+C-content gram-positive bacteria isolated from whole-crop paddy rice silage were classified and subjected to phenotypic and genetic analyses. Based on morphological and biochemical characters, these presumptive lactic acid bacterium (LAB) isolates were divided into 10 groups that included members of the genera Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Pediococcus, and Weissella. Analysis of the 16S ribosomal DNA (rDNA) was used to confirm the presence of the predominant groups indicated by phenotypic analysis and to determine the phylogenetic affiliation of representative strains. The virtually complete 16S rRNA gene was PCR amplified and sequenced. The sequences from the various LAB isolates showed high degrees of similarity to those of the GenBank reference strains (between 98.7 and 99.8%). Phylogenetic trees based on the 16S rDNA sequence displayed high consistency, with nodes supported by high bootstrap values. With the exception of one species, the genetic data was in agreement with the phenotypic identification. The prevalent LAB, predominantly homofermentative (66%), consisted of Lactobacillus plantarum (24%), Lactococcus lactis (22%), Leuconostoc pseudomesenteroides (20%), Pediococcus acidilactici (11%), Lactobacillus brevis (11%), Enterococcus faecalis (7%), Weissella kimchii (3%), and Pediococcus pentosaceus (2%). The present study, the first to fully document rice-associated LAB, showed a very diverse community of LAB with a relatively high number of species involved in the fermentation process of paddy rice silage. The comprehensive 16S rDNA-based approach to describing LAB community structure was valuable in revealing the large diversity of bacteria inhabiting paddy rice silage and enabling the future design of appropriate inoculants aimed at improving its fermentation quality. PMID:12514026
Ennahar, Saïd; Cai, Yimin; Fujita, Yasuhito
2003-01-01
A total of 161 low-G+C-content gram-positive bacteria isolated from whole-crop paddy rice silage were classified and subjected to phenotypic and genetic analyses. Based on morphological and biochemical characters, these presumptive lactic acid bacterium (LAB) isolates were divided into 10 groups that included members of the genera Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Pediococcus, and WEISSELLA: Analysis of the 16S ribosomal DNA (rDNA) was used to confirm the presence of the predominant groups indicated by phenotypic analysis and to determine the phylogenetic affiliation of representative strains. The virtually complete 16S rRNA gene was PCR amplified and sequenced. The sequences from the various LAB isolates showed high degrees of similarity to those of the GenBank reference strains (between 98.7 and 99.8%). Phylogenetic trees based on the 16S rDNA sequence displayed high consistency, with nodes supported by high bootstrap values. With the exception of one species, the genetic data was in agreement with the phenotypic identification. The prevalent LAB, predominantly homofermentative (66%), consisted of Lactobacillus plantarum (24%), Lactococcus lactis (22%), Leuconostoc pseudomesenteroides (20%), Pediococcus acidilactici (11%), Lactobacillus brevis (11%), Enterococcus faecalis (7%), Weissella kimchii (3%), and Pediococcus pentosaceus (2%). The present study, the first to fully document rice-associated LAB, showed a very diverse community of LAB with a relatively high number of species involved in the fermentation process of paddy rice silage. The comprehensive 16S rDNA-based approach to describing LAB community structure was valuable in revealing the large diversity of bacteria inhabiting paddy rice silage and enabling the future design of appropriate inoculants aimed at improving its fermentation quality.
Bacteriocins from lactic acid bacteria: production, purification, and food applications.
De Vuyst, Luc; Leroy, Frédéric
2007-01-01
In fermented foods, lactic acid bacteria (LAB) display numerous antimicrobial activities. This is mainly due to the production of organic acids, but also of other compounds, such as bacteriocins and antifungal peptides. Several bacteriocins with industrial potential have been purified and characterized. The kinetics of bacteriocin production by LAB in relation to process factors have been studied in detail through mathematical modeling and positive predictive microbiology. Application of bacteriocin-producing starter cultures in sourdough (to increase competitiveness), in fermented sausage (anti-listerial effect), and in cheese (anti-listerial and anti-clostridial effects), have been studied during in vitro laboratory fermentations as well as on pilot-scale level. The highly promising results of these studies underline the important role that functional, bacteriocinogenic LAB strains may play in the food industry as starter cultures, co-cultures, or bioprotective cultures, to improve food quality and safety. In addition, antimicrobial production by probiotic LAB might play a role during in vivo interactions occurring in the human gastrointestinal tract, hence contributing to gut health.
In vitro activity of ceftaroline against 623 diverse strains of anaerobic bacteria.
Citron, D M; Tyrrell, K L; Merriam, C V; Goldstein, E J C
2010-04-01
The in vitro activities of ceftaroline, a novel, parenteral, broad-spectrum cephalosporin, and four comparator antimicrobials were determined against anaerobic bacteria. Against Gram-positive strains, the activity of ceftaroline was similar to that of amoxicillin-clavulanate and four to eight times greater than that of ceftriaxone. Against Gram-negative organisms, ceftaroline showed good activity against beta-lactamase-negative strains but not against the members of the Bacteroides fragilis group. Ceftaroline showed potent activity against a broad spectrum of anaerobes encountered in respiratory, skin, and soft tissue infections.
Visintin, Simonetta; Alessandria, Valentina; Valente, Antonio; Dolci, Paola; Cocolin, Luca
2016-01-04
Yeast, lactic acid bacteria (LAB) and acetic acid bacteria (AAB) populations, isolated from cocoa bean heap and box fermentations in West Africa, have been investigated. The fermentation dynamicswere determined by viable counts, and 106 yeasts, 105 LAB and 82 AAB isolateswere identified by means of rep-PCR grouping and sequencing of the rRNA genes. During the box fermentations, the most abundant species were Saccharomyces cerevisiae, Candida ethanolica, Lactobacillus fermentum, Lactobacillus plantarum, Acetobacter pasteurianus and Acetobacter syzygii, while S. cerevisiae, Schizosaccharomyces pombe, Hanseniaspora guilliermondii, Pichia manshurica, C. ethanolica, Hanseniaspora uvarum, Lb. fermentum, Lb. plantarum, A. pasteurianus and Acetobacter lovaniensis were identified in the heap fermentations. Furthermore, the most abundant species were molecularly characterized by analyzing the rep-PCR profiles. Strains grouped according to the type of fermentations and their progression during the transformation process were also highlighted. The yeast, LAB and AAB isolates were physiologically characterized to determine their ability to grow at different temperatures, as well as at different pH, and ethanol concentrations, tolerance to osmotic stress, and lactic acid and acetic acid inhibition. Temperatures of 45 °C, a pH of 2.5 to 3.5, 12% (v/v) ethanol and high concentrations of lactic and acetic acid have a significant influence on the growth of yeasts, LAB and AAB. Finally, the yeastswere screened for enzymatic activity, and the S. cerevisiae, H. guilliermondii, H. uvarumand C. ethanolica species were shown to possess several enzymes that may impact the quality of the final product.
Probiotic Potential of Lactobacillus Strains with Antifungal Activity Isolated from Animal Manure.
Ilavenil, Soundharrajan; Park, Hyung Soo; Vijayakumar, Mayakrishnan; Arasu, Mariadhas Valan; Kim, Da Hye; Ravikumar, Sivanesan; Choi, Ki Choon
2015-01-01
The aim of the study was to isolate and characterize the lactic acid bacteria (LAB) from animal manure. Among the thirty LAB strains, four strains, namely, KCC-25, KCC-26, KCC-27, and KCC-28, showed good cell growth and antifungal activity and were selected for further characterization. Biochemical and physiology properties of strains confirmed that the strains are related to the Lactobacillus sp.; further, the 16S rRNA sequencing confirmed 99.99% sequence similarity towards Lactobacillus plantarum. The strains exhibited susceptibility against commonly used antibiotics with negative hemolytic property. Strains KCC-25, KCC-26, KCC-27, and KCC-28 showed strong antifungal activity against Aspergillus fumigatus, Penicillium chrysogenum, Penicillium roqueforti, Botrytis elliptica, and Fusarium oxysporum, respectively. Fermentation studies noted that the strains were able to produce significant amount of lactic, acetic, and succinic acids. Further, the production of extracellular proteolytic and glycolytic enzymes, survival under low pH, bile salts, and gastric juice together with positive bile salt hydrolase (Bsh) activity, cholesterol lowering, cell surface hydrophobicity, and aggregation properties were the strains advantages. Thus, KCC-25, KCC-26, KCC-27, and KCC-28 could have the survival ability in the harsh condition of the digestive system in the gastrointestinal tract. In conclusion, novel L. plantarum KCC-25, KCC-26, KCC-27, and KCC-28 could be considered as potential antimicrobial probiotic strains.
Miranda-Castilleja, Dalia E.; Martínez-Peniche, Ramón Álvar; Aldrete-Tapia, J. A.; Soto-Muñoz, Lourdes; Iturriaga, Montserrat H.; Pacheco-Aguilar, J. R.; Arvizu-Medrano, Sofía M.
2016-01-01
Native lactic acid bacteria (LAB) are capable of growing during winemaking, thereby strongly affecting wine quality. The species of LAB present in musts, wines during malolactic fermentation (MLF), and barrels/filters were investigated in wineries from the emerging wine region of Queretaro, México using multiplex PCR and culture. The resistance to wine-like conditions (WLC): ethanol (10, 12, and 13%), SO2 (30 mg⋅l-1), and low pH (3.5) of native LAB strains was also studied. Five species were detected within 61 samples obtained: Oenococcus oeni, Lactobacillus plantarum, Pediococcus parvulus, Lactobacillus hilgardi, and Lactobacillus brevis. Four species (excepting L. brevis) were found in must; O. oeni and P. parvulus were ubiquitous in wine and L. plantarum and L. brevis were mainly present at the initial stage of MLF, while L. hilgardii was mostly detected at the advanced stage. Furthermore, some species detected in barrel/filter, prove them to be hazardous reservoirs. From 822 LAB isolates, only 119 resisted WLC with 10% ethanol; the number of strains able to grow in WLC with 13% ethanol decreased approximately by 50%, O. oeni being the most versatile species with 65% of resistant isolates, while Lactobacillus spp. and P. parvulus were the most strongly affected, especially those recovered from barrel/filter, with less than 10% of resistant isolates. This study evidences the presence of local strains able to be used as starter cultures, and also enabled the assessment of the risks derived from the presence of spoilage LAB strains resistant to WLC. PMID:27877164
Del Piano, Mario; Carmagnola, Stefania; Andorno, Silvano; Pagliarulo, Michela; Tari, Roberto; Mogna, Luca; Strozzi, Gian Paolo; Sforza, Filomena; Capurso, Lucio
2010-09-01
Beneficial findings concerning probiotics are increasing day by day. However, one of the most important parameter which affects the probiotic activity of a microorganism is its survival during the gastroduodenal transit. Some microencapsulation techniques could be applied to bacterial cells to improve this parameter. A comparison between the intestinal colonization by microencapsulated bacteria and the same not microencapsulated strains has been conducted in a double blind, randomized, cross-over study. The study (April to July 2005) involved 44 healthy volunteers. In particular, participants were divided into 2 groups: group A (21 participants) received a mix of probiotic strains Lactobacillus plantarum LP01 (LMG P-21021) and Bifidobacterium breve BR03 (DSM 16604) in an uncoated form, group B (23 participants) was given the same strains microencapsulated with a gastroresistant material. The not microencapsulated strains were administered at 5 x 10(9) colony forming units/strain/d for 21 days, whereas the microencapsulated bacteria were given at 1 x 10(9) colony forming units/strain/d for 21 days. At the end of the first period of treatment with probiotics a 3 weeks washout phase has been included in the study protocol. At the end of the washout period the groups were crossed: in detail, group A had the microencapsulated and group B the uncoated bacteria. The administered amounts of each strain were the same as the first treatment. The quantitative evaluation of intestinal colonization by strains microencapsulated or not microencapsulated was made by fecal samples examination at the beginning of the clinical trial, after 10 and 21 days of each treatment period. In particular, fecal heterofermentative Lactobacilli and Bifidobacteria have been counted. A statistically significant increase in the fecal amounts of Lactobacilli and Bifidobacteria was recorded in both groups at the end of each treatment compared with d0 or d42 (P<0.0001 and P<0.0001 at d21, P<0.0001 and
Durighello, Emie; Christie-Oleza, Joseph Alexander; Armengaud, Jean
2014-01-01
Bacteria from the Roseobacter clade are abundant in surface marine ecosystems as over 10% of bacterial cells in the open ocean and 20% in coastal waters belong to this group. In order to document how these marine bacteria interact with their environment, we analyzed the exoproteome of Phaeobacter strain DSM 17395. We grew the strain in marine medium, collected the exoproteome and catalogued its content with high-throughput nanoLC-MS/MS shotgun proteomics. The major component represented 60% of the total protein content but was refractory to either classical proteomic identification or proteogenomics. We de novo sequenced this abundant protein with high-resolution tandem mass spectra which turned out being the 53 kDa RTX-toxin ZP_02147451. It comprised a peptidase M10 serralysin domain. We explained its recalcitrance to trypsin proteolysis and proteomic identification by its unusual low number of basic residues. We found this is a conserved trait in RTX-toxins from Roseobacter strains which probably explains their persistence in the harsh conditions around bacteria. Comprehensive analysis of exoproteomes from environmental bacteria should take into account this proteolytic recalcitrance.
2014-01-01
Background The raw goat milk microbiota is considered a good source of novel bacteriocinogenic lactic acid bacteria (LAB) strains that can be exploited as an alternative for use as biopreservatives in foods. The constant demand for such alternative tools justifies studies that investigate the antimicrobial potential of such strains. Results The obtained data identified a predominance of Lactococcus and Enterococcus strains in raw goat milk microbiota with antimicrobial activity against Listeria monocytogenes ATCC 7644. Enzymatic assays confirmed the bacteriocinogenic nature of the antimicrobial substances produced by the isolated strains, and PCR reactions detected a variety of bacteriocin-related genes in their genomes. Rep-PCR identified broad genetic variability among the Enterococcus isolates, and close relations between the Lactococcus strains. The sequencing of PCR products from nis-positive Lactococcus allowed the identification of a predicted nisin variant not previously described and possessing a wide inhibitory spectrum. Conclusions Raw goat milk was confirmed as a good source of novel bacteriocinogenic LAB strains, having identified Lactococcus isolates possessing variations in their genomes that suggest the production of a nisin variant not yet described and with potential for use as biopreservatives in food due to its broad spectrum of action. PMID:24521354
Monitoring of wheat lactic acid bacteria from the field until the first step of dough fermentation.
Alfonzo, Antonio; Miceli, Claudia; Nasca, Anna; Franciosi, Elena; Ventimiglia, Giusi; Di Gerlando, Rosalia; Tuohy, Kieran; Francesca, Nicola; Moschetti, Giancarlo; Settanni, Luca
2017-04-01
The present work was carried out to retrieve the origin of lactic acid bacteria (LAB) in sourdough. To this purpose, wheat LAB were monitored from ear harvest until the first step of fermentation for sourdough development. The influence of the geographical area and variety on LAB species/strain composition was also determined. The ears of four Triticum durum varieties (Duilio, Iride, Saragolla and Simeto) were collected from several fields located within the Palermo province (Sicily, Italy) and microbiologically investigated. In order to trace the transfer of LAB during the consecutive steps of manipulation, ears were transformed aseptically and, after threshing, milling and fermentation, samples of kernels, semolinas and doughs, respectively, were analysed. LAB were not found to dominate the microbial communities of the raw materials. In general, kernels harboured lower levels of microorganisms than ears and ears than semolinas. Several samples showing no development of LAB colonies acidified the enrichment broth suggesting the presence of LAB below the detection limit. After fermentation, LAB loads increased consistently for all doughs, reaching levels of 7.0-7.5 Log CFU/g on M17. The values of pH (5.0) and TTA (5.6 mL NaOH/10 g of dough) indicated the occurrence of the acidification process for several doughs. LAB were phenotypically and genotypically differentiated by randomly amplified polymorphic DNA (RAPD)-PCR into eight groups including 51 strains belonging to the species Lactobacillus brevis, Lactobacillus coryniformis, Lactobacillus plantarum, Lactococcus lactis, Lactococcus garvieae, Enterococcus casseliflavus, Enterococcus faecium, Leuconostoc citreum, and Pediococcus pentosaceus. Lactobacilli constituted a minority the LAB community, while lactococci represented more than 50% of strains. Lower LAB complexity was found on kernels, while a richer biodiversity was observed in semolinas and fermented doughs. For broader microbiota characterisation in
Awaisheh, Saddam S; Ibrahim, Salam A
2009-11-01
The objective of this work was to screen the antibacterial activity of lactic acid bacteria (LAB) isolated from different sources against different pathogens found in ready-to-eat vacuum-packaged meat products (RTE-VPMP). LAB were isolated from human, RTE-VPMP, fermented vegetables, and dairy samples. These isolates were assessed for their antibacterial activity against Escherichia coli O157:H7, Salmonella spp., Listeria monocytogenes, and Staphylococcus aureus using spot on lawn technique. Six LAB isolates-three from a human source, two from a RTE-VPMP source, and one from a fermented vegetable source-were found to be effective against all pathogenic strains. Antibacterial activities of cell-free neutral supernatant broths of these isolates were assessed against the different pathogenic strains to confirm bacteriocin production. All six isolates were effective against all pathogenic strains. LAB isolates from the human source had the highest antibacterial activity and were significantly more effective than other LAB isolates, with the inhibition zone ranging from 14 to 22 mm. Inhibition zones of RTE-VPMP LAB isolates were lower than those of human origin (inhibition zone range, 11-17 mm). The lowest activities were for the fermented vegetable isolate, for which inhibition zones ranged from 11 to 15 mm. The three isolates of human origin were identified as L. acidophilus, L. casei, and L. reuteri; the two isolates from RTE-VPMP source were both L. sake; and the one isolate of fermented vegetable origin was L. plantarum. Our results showed that nonmeat product-sourced LAB were effective against several foodborne pathogens, which suggests that they could be used as natural biopreservatives in many RTE-VPMP produced in Jordan.
Chen, Yi-sheng; Wu, Hui-chung; Li, Ya-han; Leong, Kun-hon; Pua, Xiao-hui; Weng, Ming-kai; Yanagida, Fujitoshi
2012-01-30
Sian-sianzih (fermented clams) is a popular traditional fermented food in Taiwan. The lactic acid bacteria (LAB) microflora in sian-sianzih have not been studied in detail. In this study, LAB from sian-sianzih were isolated, characterized and identified. A total of 186 cultures of LAB were isolated from seven sian-sianzih samples and 29 cultures were isolated from its main raw substrate: clams. The identification results revealed up to 11 distinct bacterial species belonging to five genera in sian-sianzih, and three species belonging to two genera in clams. The most common bacterial genera in sian-sianzih were Lactobacillus and Weissella, followed by Leuconostoc, Pediococcus and Lactococcus. A regional similarity in LAB, with differences in diversity, was observed in the current study. On the other hand, Lactococcus lactis subsp. lactis was the most common species found in raw clam samples. The results also suggested that greater LAB diversity could be observed in wild clams than in cultured ones. Furthermore, antibacterial activities of the isolates were determined, and one Weisella hellenica strain showed inhibitory activity against the indicator strain Lactobacilluas sakei JCM 1157(T) . A sensory assessment of seven sian-sianzih samples was also performed and the results indicated that diversity of LAB has a great effect on its aroma and taste formation. The results demonstrate that various LAB species are distributed in sian-sianzih and have a great effect on the flavor of sian-sianzih. Copyright © 2011 Society of Chemical Industry.
Kavitha, Murugan; Selvi, M. S.; Selvam, Govindan Sadasivam
2014-01-01
Lactic acid bacteria (LAB) have the potential to degrade intestinal oxalate and this is increasingly being studied as a promising probiotic solution to manage kidney stone disease. In this study, oxalate degrading LAB were isolated from human faeces and south Indian fermented foods, subsequently assessed for potential probiotic property in vitro and in vivo. Based on preliminary characteristics, 251 out of 673 bacterial isolates were identified as LAB. A total of 17 strains were found to degrade oxalate significantly between 40.38% and 62.90% and were subjected to acid and bile tolerance test. Among them, nine strains exhibited considerable tolerance up to pH 3.0 and at 0.3% bile. These were identified as Lactobacillus fermentum and Lactobacillus salivarius using 16S rDNA sequencing. Three strains, Lactobacillus fermentum TY5, Lactobacillus fermentum AB1, and Lactobacillus salivarius AB11, exhibited good adhesion to HT-29 cells and strong antimicrobial activity. They also conferred resistance to kanamycin, rifampicin, and ampicillin, but were sensitive to chloramphenicol and erythromycin. The faecal recovery rate of these strains was observed as 15.16% (TY5), 6.71% (AB1), and 9.3% (AB11) which indicates the colonization ability. In conclusion, three efficient oxalate degrading LAB were identified and their safety assessments suggest that they may serve as good probiotic candidates for preventing hyperoxaluria. PMID:24723820
Nediani, Miriam T.; García, Luis; Saavedra, Lucila; Martínez, Sandra; López Alzogaray, Soledad; Fadda, Silvina
2017-01-01
Quality and safety are important challenges in traditional fermented sausage technology. Consequently, the development of a tailored starter culture based on indigenous microbiota constitutes an interesting alternative. In the present study, spontaneously fermented goat meat sausages were created and analyzed using a physicochemical and microbiological approach. Thereafter 170 lactic acid bacteria (LAB) strains were isolated and preliminary characterized by phenotypic assays. The hygienic and technological properties, and growth and fermentative potential of isolates using a goat-meat-based culture medium were evaluated. All strains proved to have bioprotective features due to their acidogenic metabolism. Almost all grew optimally in meat environments. LAB isolates presented proteolytic activity against meat proteins and enriched amino acid contents of the goat-meat-based model. The most efficient strains were four different Lactobacillus sakei isolates, as identified by genotyping and RAPD analysis. L. sakei strains are proposed as optimal candidates to improve the production of fermented goat meat sausages, creating a new added-value fermented product. PMID:28513575
Nediani, Miriam T; García, Luis; Saavedra, Lucila; Martínez, Sandra; López Alzogaray, Soledad; Fadda, Silvina
2017-05-17
Quality and safety are important challenges in traditional fermented sausage technology. Consequently, the development of a tailored starter culture based on indigenous microbiota constitutes an interesting alternative. In the present study, spontaneously fermented goat meat sausages were created and analyzed using a physicochemical and microbiological approach. Thereafter 170 lactic acid bacteria (LAB) strains were isolated and preliminary characterized by phenotypic assays. The hygienic and technological properties, and growth and fermentative potential of isolates using a goat-meat-based culture medium were evaluated. All strains proved to have bioprotective features due to their acidogenic metabolism. Almost all grew optimally in meat environments. LAB isolates presented proteolytic activity against meat proteins and enriched amino acid contents of the goat-meat-based model. The most efficient strains were four different Lactobacillus sakei isolates, as identified by genotyping and RAPD analysis. L. sakei strains are proposed as optimal candidates to improve the production of fermented goat meat sausages, creating a new added-value fermented product.
Production of Value-added Products by Lactic Acid Bacteria
USDA-ARS?s Scientific Manuscript database
Lactic acid bacteria (LAB) are a group of facultative anaerobic, catalase negative, nonmotile and nonsporeforming–Gram positive bacteria. Most LAB utilize high energy C sources including monomer sugars to produce energy to maintain cellular structure and function. This anaerobic fermentation proce...
NASA Astrophysics Data System (ADS)
Julich, S.; Kopinč, R.; Hlawatsch, N.; Moche, C.; Lapanje, A.; Gärtner, C.; Tomaso, H.
2014-05-01
Lab-on-a-chip systems are innovative tools for the detection and identification of microbial pathogens in human and veterinary medicine. The major advantages are small sample volume and a compact design. Several fluidic modules have been developed to transform analytical procedures into miniaturized scale including sampling, sample preparation, target enrichment, and detection procedures. We present evaluation data for single modules that will be integrated in a chip system for the detection of pathogens. A microfluidic chip for purification of nucleic acids was established for cell lysis using magnetic beads. This assay was evaluated with spiked environmental aerosol and swab samples. Bacillus thuringiensis was used as simulant for Bacillus anthracis, which is closely related but non-pathogenic for humans. Stationary PCR and a flow-through PCR chip module were investigated for specific detection of six highly pathogenic bacteria. The conventional PCR assays could be transferred into miniaturized scale using the same temperature/time profile. We could demonstrate that the microfluidic chip modules are suitable for the respective purposes and are promising tools for the detection of bacterial pathogens. Future developments will focus on the integration of these separate modules to an entire lab-on-a-chip system.
Dual-coated lactic acid bacteria: an emerging innovative technology in the field of probiotics.
Alvarez-Calatayud, Guillermo; Margolles, Abelardo
2016-01-01
Probiotics are living micro-organisms that do not naturally have shelf life, and normally are weakly protected against the digestive action of the GI tract. A new dual coating technology has been developed in an effort to maximize survival, that is, to be able to reach the intestine alive and in sufficient numbers to confer the beneficial health effects on the host. Dual-coating of lactic acid bacteria (LAB) is the result of fourth-generation coating technology for the protection of these bacteria at least 100-fold or greater than the uncoated LAB. This innovative technique involves a first pH-dependent protein layer that protects bacteria from gastric acid and bile salt, and a second polysaccharide matrix that protects bacteria from external factors, such as humidity, temperature and pressure, as well as the digestive action during the passage through the GI tract. Dual-coated probiotic formulation is applicable to different therapeutic areas, including irritable bowel syndrome, atopic dermatitis, acute diarrhea, chronic constipation, Helicobacter pylori eradication, and prevention of antibiotic-associated diarrhea. An updated review of the efficacy of doubly coated probiotic strains for improving bacterial survival in the intestinal tract and its consequent clinical benefits in humans is here presented.
Citron, Diane M.; Warren, Yumi A.; Goldstein, Ellie J. C.
2012-01-01
TD-1792 is a multivalent glycopeptide-cephalosporin heterodimer antibiotic with potent activity against Gram-positive bacteria. We tested TD-1792 against 377 anaerobes and 34 strains of Corynebacterium species. Against nearly all Gram-positive strains, TD-1792 had an MIC90 of 0.25 μg/ml and was typically 3 to 7 dilutions more active than vancomycin and daptomycin. PMID:22290981
Dong, Yuemei; Iniguez, A. Leonardo; Ahmer, Brian M. M.; Triplett, Eric W.
2003-01-01
The presence of human-pathogenic, enteric bacteria on the surface and in the interior of raw produce is a significant health concern. Several aspects of the biology of the interaction between these bacteria and alfalfa (Medicago sativa) seedlings are addressed here. A collection of enteric bacteria associated with alfalfa sprout contaminations, along with Escherichia coli K-12, Salmonella enterica serotype Typhimurium strain ATCC 14028, and an endophyte of maize, Klebsiella pneumoniae 342, were labeled with green fluorescent protein, and their abilities to colonize the rhizosphere and the interior of the plant were compared. These strains differed widely in their endophytic colonization abilities, with K. pneumoniae 342 and E. coli K-12 being the best and worst colonizers, respectively. The abilities of the pathogens were between those of K. pneumoniae 342 and E. coli K-12. All Salmonella bacteria colonized the interiors of the seedlings in high numbers with an inoculum of 102 CFU, although infection characteristics were different for each strain. For most strains, a strong correlation between endophytic colonization and rhizosphere colonization was observed. These results show significant strain specificity for plant entry by these strains. Significant colonization of lateral root cracks was observed, suggesting that this may be the site of entry into the plant for these bacteria. At low inoculum levels, a symbiosis mutant of Medicago truncatula, dmi1, was colonized in higher numbers on the rhizosphere and in the interior by a Salmonella endophyte than was the wild-type host. Endophytic entry of M. truncatula appears to occur by a mechanism independent of the symbiotic infections by Sinorhizobium meliloti or mycorrhizal fungi. PMID:12620870
Predominant Effect of Host Genetics on Levels of Lactobacillus johnsonii Bacteria in the Mouse Gut▿†
Buhnik-Rosenblau, Keren; Danin-Poleg, Yael; Kashi, Yechezkel
2011-01-01
The gut microbiota is strongly associated with the well-being of the host. Its composition is affected by environmental factors, such as food and maternal inoculation, while the relative impact of the host's genetics have been recently uncovered. Here, we studied the effect of the host genetic background on the composition of intestinal bacteria in a murine model, focusing on lactic acid bacteria (LAB) as an important group that includes many probiotic strains. Based on 16S rRNA gene genotyping, variation was observed in fecal LAB populations of BALB/c and C57BL/6J mouse lines. Lactobacillus johnsonii, a potentially probiotic bacterium, appeared at significantly higher levels in C57BL/6J versus BALB/c mouse feces. In the BALB/c gut, the L. johnsonii level decreased rapidly after oral administration, suggesting that some selective force does not allow its persistence at higher levels. The genetic inheritance of L. johnsonii levels was further tested in reciprocal crosses between the two mouse lines. The resultant F1 offspring presented similar L. johnsonii levels, confirming that mouse genetics plays a major role in determining these levels compared to the smaller maternal effect. Our findings suggest that mouse genetics has a major effect on the composition of the LAB population in general and on the persistence of L. johnsonii in the gut in particular. Concentrating on a narrow spectrum of culturable LAB enables the isolation and characterization of such potentially probiotic bacterial strains, which might be specifically oriented to the genetic background of the host as part of a personalized-medicine approach. PMID:21803912
Durighello, Emie; Christie-Oleza, Joseph Alexander; Armengaud, Jean
2014-01-01
Bacteria from the Roseobacter clade are abundant in surface marine ecosystems as over 10% of bacterial cells in the open ocean and 20% in coastal waters belong to this group. In order to document how these marine bacteria interact with their environment, we analyzed the exoproteome of Phaeobacter strain DSM 17395. We grew the strain in marine medium, collected the exoproteome and catalogued its content with high-throughput nanoLC-MS/MS shotgun proteomics. The major component represented 60% of the total protein content but was refractory to either classical proteomic identification or proteogenomics. We de novo sequenced this abundant protein with high-resolution tandem mass spectra which turned out being the 53 kDa RTX-toxin ZP_02147451. It comprised a peptidase M10 serralysin domain. We explained its recalcitrance to trypsin proteolysis and proteomic identification by its unusual low number of basic residues. We found this is a conserved trait in RTX-toxins from Roseobacter strains which probably explains their persistence in the harsh conditions around bacteria. Comprehensive analysis of exoproteomes from environmental bacteria should take into account this proteolytic recalcitrance. PMID:24586966
Lactic acid bacteria and yeasts associated with gowé production from sorghum in Bénin.
Vieira-Dalodé, G; Jespersen, L; Hounhouigan, J; Moller, P L; Nago, C M; Jakobsen, M
2007-08-01
To identify the dominant micro-organisms involved in the production of gowé, a fermented beverage, and to select the most appropriate species for starter culture development. Samples of sorghum gowé produced twice at three different production sites were taken at different fermentation times. DNA amplification by internal transcribed spacer-polymerase chain reaction of 288 lactic acid bacteria (LAB) isolates and 16S rRNA gene sequencing of selected strains revealed that the dominant LAB responsible for gowé fermentation were Lactobacillus fermentum, Weissella confusa, Lactobacillus mucosae, Pediococcus acidilactici, Pediococcus pentosaceus and Weissella kimchii. DNA from 200 strains of yeasts was amplified and the D1/D2 domain of the 26S rRNA gene was sequenced for selected isolates, revealing that the yeasts species were Kluyveromyces marxianus, Pichia anomala, Candida krusei and Candida tropicalis. Gowé processing is characterized by a mixed fermentation dominated by Lact. fermentum, W. confusa and Ped. acidilactici for the LAB and by K. marxianus, P. anomala and C. krusei for the yeasts. The diversity of the LAB and yeasts identified offers new opportunities for technology upgrading and products development in gowé production. The identified species can be used as possible starter for a controlled fermentation of gowé.
Fink, Lisbeth N; Zeuthen, Louise H; Ferlazzo, Guido; Frøkiaer, Hanne
2007-12-01
The intestinal microbiota is essential for homeostasis of the local and systemic immune system, and particularly strains of lactic acid bacteria and Escherichia coli have been shown to have balancing effects on inflammatory conditions such as allergy and inflammatory bowel disease. However, in vitro assessment of the immunomodulatory effects of distinct strains may depend strongly on the cell type used as a model. To select the most appropriate model for screening of beneficial bacteria in human cells, the response to strains of intestinal bacteria of three types of antigen-presenting cells (APC) was compared; blood myeloid dendritic cells (DC), monocyte-derived DC and monocytes, and the effector response of natural killer cells and naïve T cells was characterized. Maturation induced by gut-derived bacteria differed between APC, with blood DC and monocytes responding with the production of IL-6 and tumour necrosis factor-alpha to bacteria, which elicited mainly IL-10 in monocyte-derived DC. In contrast, comparable IFN-gamma production patterns were found in both natural killer cells and T cells induced by all bacteria-matured APC. An inhibitory effect of certain strains on this IFN-gamma production was also mediated by all types of APC. The most potent responses were induced by monocyte-derived DC, which thus constitute a sensitive screening model.
Itoh, Hiroshi; Matsuo, Hidemasa; Kitamura, Naoko; Yamamoto, Sho; Higuchi, Takeshi; Takematsu, Hiromu; Kamikubo, Yasuhiko; Kondo, Tadakazu; Yamashita, Kouhei; Sasada, Masataka; Takaori-Kondo, Akifumi; Adachi, Souichi
2015-07-01
Autophagy occurs in human neutrophils after the phagocytosis of multidrug-resistant bacteria and drug-sensitive strains, including Escherichia coli and Pseudomonas aeruginosa. The present study detected autophagy by immunoblot analysis of LC3B conversion, by confocal scanning microscopic examination of LC3B aggregate formation and by transmission electron microscopic examination of bacteria-containing autophagosomes. Patients with severe bacterial infections are often treated with IVIG alongside antimicrobial agents. Here, we showed that IVIG induced neutrophil-mediated phagocytosis of multidrug-resistant strains. Compared with untreated neutrophils, neutrophils exposed to IVIG showed increased levels of bacterial cell killing, phagocytosis, O(2)(-) release, MPO release, and NET formation. IVIG also increased autophagy in these cells. Inhibiting the late phase of autophagy (fusion of lysosomes with autophagosomes) with bafilomycin A1-reduced, neutrophil-mediated bactericidal activity. These findings indicate that autophagy plays a critical role in the bactericidal activity mediated by human neutrophils. Furthermore, the autophagosomes within the neutrophils contained bacteria only and their organelles only, or both bacteria and their organelles, a previously undocumented observation. Taken together, these results suggest that the contents of neutrophil autophagosomes may be derived from specific autophagic systems, which provide the neutrophil with an advantage. Thus, IVIG promotes the neutrophil-mediated killing of multidrug-resistant bacteria as well as drug-sensitive strains. © Society for Leukocyte Biology.
Itoh, Hiroshi; Matsuo, Hidemasa; Kitamura, Naoko; Yamamoto, Sho; Higuchi, Takeshi; Takematsu, Hiromu; Kamikubo, Yasuhiko; Kondo, Tadakazu; Yamashita, Kouhei; Sasada, Masataka; Takaori-Kondo, Akifumi; Adachi, Souichi
2015-01-01
Autophagy occurs in human neutrophils after the phagocytosis of multidrug-resistant bacteria and drug-sensitive strains, including Escherichia coli and Pseudomonas aeruginosa. The present study detected autophagy by immunoblot analysis of LC3B conversion, by confocal scanning microscopic examination of LC3B aggregate formation and by transmission electron microscopic examination of bacteria-containing autophagosomes. Patients with severe bacterial infections are often treated with IVIG alongside antimicrobial agents. Here, we showed that IVIG induced neutrophil-mediated phagocytosis of multidrug-resistant strains. Compared with untreated neutrophils, neutrophils exposed to IVIG showed increased levels of bacterial cell killing, phagocytosis, O2− release, MPO release, and NET formation. IVIG also increased autophagy in these cells. Inhibiting the late phase of autophagy (fusion of lysosomes with autophagosomes) with bafilomycin A1-reduced, neutrophil-mediated bactericidal activity. These findings indicate that autophagy plays a critical role in the bactericidal activity mediated by human neutrophils. Furthermore, the autophagosomes within the neutrophils contained bacteria only and their organelles only, or both bacteria and their organelles, a previously undocumented observation. Taken together, these results suggest that the contents of neutrophil autophagosomes may be derived from specific autophagic systems, which provide the neutrophil with an advantage. Thus, IVIG promotes the neutrophil-mediated killing of multidrug-resistant bacteria as well as drug-sensitive strains. PMID:25908735
Bacteria Culture Test: MedlinePlus Lab Test Information
... Information → Bacteria Culture Test URL of this page: https://medlineplus.gov/labtests/bacteriaculturetest.html Bacteria Culture Test ... 2017 Mar 4]; [about 3 screens]. Available from: https://labtestsonline.org/understanding/analytes/sputum-culture/tab/test/ ...
Pacheco da Rosa, Juliana; Korenblum, Elisa; Franco-Cirigliano, Marcella Novaes; Abreu, Fernanda; Lins, Ulysses; Soares, Rosângela M A; Macrae, Andrew; Seldin, Lucy; Coelho, Rosalie R R
2013-01-01
Four actinomycete strains previously isolated from Brazilian soils were tested for their antimicrobial activity against Bacillus pumilus LF-4 and Desulfovibrio alaskensis NCIMB 13491, bacteria that are well known to be involved in biofilm formation and biocorrosion. Strain 235, belonging to the species Streptomyces lunalinharesii, inhibited the growth of both bacteria. The antimicrobial activity was seen over a wide range of pH, and after treatment with several chemicals and heat but not with proteinase K and trypsin. The antimicrobial substances present in the concentrated supernatant from growth media were partially characterized by SDS-PAGE and extracellular polypeptides were seen. Bands in the size range of 12 to 14.4 kDa caused antimicrobial activity. Transmission electron microscopy of D. alaskensis cells treated with the concentrated supernatant containing the antimicrobial substances revealed the formation of prominent bubbles, the spherical double-layered structures on the cell membrane, and the periplasmic space completely filled with electron-dense material. This is the first report on the production of antimicrobial substances by actinomycetes against bacteria involved in biocorrosion processes, and these findings may be of great relevance as an alternative source of biocides to those currently employed in the petroleum industry.
Anandharaj, Marimuthu; Sivasankari, Balayogan; Santhanakaruppu, Rajendran; Manimaran, Muthusamy; Rani, Rizwana Parveen; Sivakumar, Subramaniyan
2015-06-01
This study sought to evaluate the probiotic potential of lactic acid bacteria (LAB) isolated from traditionally fermented south Indian koozh and gherkin (cucumber). A total of 51 LAB strains were isolated, among which four were identified as Lactobacillus spp. and three as Weissella spp. The strains were screened for their probiotic potential. All isolated Lactobacillus and Weissella strains were capable of surviving under low pH and bile salt conditions. GI9 and FKI21 were able to survive at pH 2.0 and 0.50% bile salt for 3 h without losing their viability. All LAB strains exhibited inhibitory activity against tested pathogens and were able to deconjugate bile salt. Higher deconjugation was observed in the presence of sodium glycocholate (P < 0.05). Strain FKI21 showed maximum auto-aggregation (79%) and co-aggregation with Escherichia coli MTCC 1089 (68%). Exopolysaccharide production of LAB strains ranged from 68.39 to 127.12 mg/L (P < 0.05). Moreover, GI9 (58.08 μg/ml) and FKI21 (56.25 μg/ml) exhibited maximum cholesterol reduction with bile salts. 16S rRNA sequencing confirmed GI9 and FKI21 as Lactobacillus crispatus and Weissella koreensis, respectively. This is the first study to report isolation of W. koreensis FKI21 from fermented koozh and demonstrates its cholesterol-reducing potential. Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.
Manitchotpisit, Pennapa; Bischoff, Kenneth M; Price, Neil P J; Leathers, Timothy D
2013-05-01
Lactic acid bacteria (LAB) frequently contaminate commercial fuel ethanol fermentations, reducing yields and decreasing profitability of biofuel production. Microorganisms from environmental sources in different geographic regions of Thailand were tested for antibacterial activity against LAB. Four bacterial strains, designated as ALT3A, ALT3B, ALT17, and MR1, produced inhibitory effects on growth of LAB. Sequencing of rRNA identified these strains as species of Bacillus subtilis (ALT3A and ALT3B) and B. cereus (ALT17 and MR1). Cell mass from colonies and agar samples from inhibition zones were analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry. The spectra of ALT3A and ALT3B showed a strong signal at m/z 1,060, similar in mass to the surfactin family of antimicrobial lipopeptides. ALT3A and ALT3B were analyzed by zymogram analysis using SDS-PAGE gels placed on agar plates inoculated with LAB. Cell lysates possessed an inhibitory protein of less than 10 kDa, consistent with the production of an antibacterial lipopeptide. Mass spectra of ALT17 and MR1 had notable signals at m/z 908 and 930 in the whole cell extracts and at m/z 687 in agar, but these masses do not correlate with those of previously reported antibacterial lipopeptides, and no antibacterial activity was detected by zymogram. The antibacterial activities produced by these strains may have application in the fuel ethanol industry as an alternative to antibiotics for prevention and control of bacterial contamination.
Yang, Jinsong; Tan, Haisheng; Cai, Yimin
2016-07-01
The natural lactic acid bacteria (LAB) population, chemical composition, and silage fermentation of fruit residues were studied. Eighty-two strains of LAB were isolated from fruit residues such as banana leaf and stem, pineapple peel, and papaya peel. All strains were gram-positive and catalase-negative bacteria, and they were divided into 7 groups (A-G) according to morphological and biochemical characters. Strains in groups A to F were rods, and group G was cocci. Group F produced gas from glucose; other groups did not. Groups A to C and F formed dl-lactic acid, whereas groups D, E, and G formed l-lactic acid. Based on the 16S rRNA gene sequence and DNA-DNA hybridization analysis, groups A to G strains were identified as Lactobacillus plantarum (54.9% of the total isolates), Lactobacillus paraplantarum (3.6%), Lactobacillus nagelii (8.5%), Lactobacillus perolens (4.9%), Lactobacillus casei (11.0%), Lactobacillus fermentum (9.8%), and Enterococcus gallinarum (7.3%), respectively. Lactobacillus plantarum and Lactobacillus casei are the most frequently isolated from fruit residues as a dominant species, and they could grow at a lower pH conditions and produce more lactic acid than other isolates. Pineapple and papaya peels contained higher crude protein (11.5-13.8%) and water-soluble carbohydrate (16.8-22.4%), but lower acid detergent fiber contents (21.2 to 26.4%) than banana stems and leaves (8.2% crude protein, 42.8% acid detergent fiber, and 5.1% water-soluble carbohydrate). Compared with banana stem and leaf silages, the pineapple and papaya peel silages were well preserved with a lower pH and higher lactate content. The study suggests that the fruit residues contain excellent LAB species and abundant feed nutrients, and that they can be preserved as silage to be potential food resources for livestock. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
Genís, Sandra; Sánchez-Chardi, Alejandro; Bach, Àlex; Fàbregas, Francesc; Arís, Anna
2017-01-01
Uterine function in cattle is compromised by bacterial contamination and inflammation after calving. The objective of this study was to select a combination of lactic acid bacteria (LAB) to decrease endometrium inflammation and Escherichia coli infection. Primary endometrial epithelial cells were cultured in vitro to select the most favorable LAB combination modulating basal tissue inflammation and E. coli infection. Supernatants were obtained to determine expression of pro-inflammatory cytokines, and E. coli infection was evaluated after harvesting the tissue and plate counting. The selected LAB combination was tested in uterus explants to assess its capacity to modulate basal and acute inflammation (associated with E. coli infection). The combination of Lactobacillus rhamnosus, Pediococcus acidilactici, and Lactobacillus reuteri at a ratio of 25:25:2, respectively, reduced E. coli infection in vitro with (89.77%) or without basal tissue inflammation (95.10%) compared with single LAB strains. Lactic acid bacteria treatment reduced CXCL8 and IL1B expression 4.7- and 2.2-fold, respectively, under acute inflammation. Ex vivo, the tested LAB combination reduced acute inflammation under E. coli infection, decreasing IL-8, IL-1β, and IL-6 up to 2.2-, 2.5-, and 2.2-fold, respectively. In the total inflammation model, the LAB combination decreased IL-8 1.6-fold and IL-6 1.2-fold. Ultrastructural evaluation of the tissue suggested no direct interaction between the LAB and E. coli, although pathological effects of E. coli in endometrial cells were greatly diminished or even reversed by the LAB combination. This study shows the promising potential of LAB probiotics for therapeutic use against endometrial inflammation and infection. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
Bulgasem, Bulgasem Y.; Lani, Mohd Nizam; Wan Yusoff, Wan Mohtar; Fnaish, Sumaya G.
2016-01-01
The role of lactic acid bacteria (LAB) in honey as antifungal activity has received little attention and their mechanism of inhibitory of fungi is not fully understood. In this study, LAB were isolated from honey samples from Malaysia, Libya, Saudi Arabia, and Yemen. Twenty-five isolates were confirmed LAB by catalase test and Gram staining, and were screened for antifungal activity. Four LAB showed inhibitory activity against Candida spp. using the dual agar overlay method. And they were identified as Lactobacillus plantarum HS isolated from Al-Seder honey, Lactobacillus curvatus HH isolated from Al-Hanon honey, Pediococcus acidilactici HC isolated from Tualang honey and Pediococcus pentosaceus HM isolated from Al-Maray honey by the 16S rDNA sequence. The growth of Candida glabrata ATCC 2001 was strongly inhibited (>15.0 mm) and (10~15 mm) by the isolates of L. curvatus HH and P. pentosaceus HM, respectively. The antifungal activity of the crude supernatant (cell free supernatant, CFS) was evaluated using well diffusion method. The CFS showed high antifungal activity against Candida spp. especially The CFS of L. curvatus HH was significantly (p < 0.05) inhibited growth of C. glabrata ATCC 2001, C. parapsilosis ATCC 2201, and C. tropicalis ATCC 750 with inhibitory zone 22.0, 15.6, and 14.7 mm, respectively. While CFS of P. pentosaceus HM was significantly (p < 0.05) effective against C. krusei, C. glabrata, and C. albicans with inhibition zone 17.2, 16.0, and 13.3 mm, respectively. The results indicated that LAB isolated from honey produced compounds which can be used to inhibit the growth of the pathogenic Candida species. PMID:28154488
Bulgasem, Bulgasem Y; Lani, Mohd Nizam; Hassan, Zaiton; Wan Yusoff, Wan Mohtar; Fnaish, Sumaya G
2016-12-01
The role of lactic acid bacteria (LAB) in honey as antifungal activity has received little attention and their mechanism of inhibitory of fungi is not fully understood. In this study, LAB were isolated from honey samples from Malaysia, Libya, Saudi Arabia, and Yemen. Twenty-five isolates were confirmed LAB by catalase test and Gram staining, and were screened for antifungal activity. Four LAB showed inhibitory activity against Candida spp. using the dual agar overlay method. And they were identified as Lactobacillus plantarum HS isolated from Al-Seder honey, Lactobacillus curvatus HH isolated from Al-Hanon honey, Pediococcus acidilactici HC isolated from Tualang honey and Pediococcus pentosaceus HM isolated from Al-Maray honey by the 16S rDNA sequence. The growth of Candida glabrata ATCC 2001 was strongly inhibited (>15.0 mm) and (10~15 mm) by the isolates of L. curvatus HH and P. pentosaceus HM, respectively. The antifungal activity of the crude supernatant (cell free supernatant, CFS) was evaluated using well diffusion method. The CFS showed high antifungal activity against Candida spp. especially The CFS of L. curvatus HH was significantly ( p < 0.05) inhibited growth of C. glabrata ATCC 2001, C. parapsilosis ATCC 2201, and C. tropicalis ATCC 750 with inhibitory zone 22.0, 15.6, and 14.7 mm, respectively. While CFS of P. pentosaceus HM was significantly ( p < 0.05) effective against C. krusei , C. glabrata , and C. albicans with inhibition zone 17.2, 16.0, and 13.3 mm, respectively. The results indicated that LAB isolated from honey produced compounds which can be used to inhibit the growth of the pathogenic Candida species.
Tulini, Fabricio L; Hymery, Nolwenn; Haertlé, Thomas; Le Blay, Gwenaelle; De Martinis, Elaine C P
2016-02-01
Lactic acid bacteria (LAB) can be isolated from different sources such as milk and cheese, and the lipolytic, proteolytic and glycolytic enzymes of LAB are important in cheese preservation and in flavour production. Moreover, LAB produce several antimicrobial compounds which make these bacteria interesting for food biopreservation. These characteristics stimulate the search of new strains with technological potential. From 156 milk and cheese samples from cow, buffalo and goat, 815 isolates were obtained on selective agars for LAB. Pure cultures were evaluated for antimicrobial activities by agar antagonism tests and for proteolytic activity on milk proteins by cultivation on agar plates. The most proteolytic isolates were also tested by cultivation in skim milk followed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the fermented milk. Among the 815 tested isolates, three of them identified as Streptococcus uberis (strains FT86, FT126 and FT190) were bacteriocin producers, whereas four other ones identified as Weissella confusa FT424, W. hellenica FT476, Leuconostoc citreum FT671 and Lactobacillus plantarum FT723 showed high antifungal activity in preliminary assays. Complementary analyses showed that the most antifungal strain was L. plantarum FT723 that inhibited Penicillium expansum in modified MRS agar (De Man, Rogosa, Sharpe, without acetate) and fermented milk model, however no inhibition was observed against Yarrowia lipolytica. The proteolytic capacities of three highly proteolytic isolates identified as Enterococcus faecalis (strains FT132 and FT522) and Lactobacillus paracasei FT700 were confirmed by SDS-PAGE, as visualized by the digestion of caseins and whey proteins (β-lactoglobulin and α-lactalbumin). These results suggest potential applications of these isolates or their activities (proteolytic activity or production of antimicrobials) in dairy foods production.
Corona, Onofrio; Alfonzo, Antonio; Ventimiglia, Giusi; Nasca, Anna; Francesca, Nicola; Martorana, Alessandra; Moschetti, Giancarlo; Settanni, Luca
2016-10-01
Four obligate heterofermentative lactic acid bacteria (LAB) strains (Weissella cibaria PON10030 and PON10032 and Leuconostoc citreum PON 10079 and PON10080) were tested as single strain starters, mono-species dual strain starters, and multiple strain starter for the preparation and propagation of sourdoughs for the production of a typical bread at industrial level. The kinetics of pH and TTA during the daily sourdough refreshments indicated a correct acidification process for all trials. The concentration of lactic and acetic acid increased consistently during fermentation. The resulting molar ratios between these two organic acids in the experimental trials were lower than those observed in the control trial. The microbiological investigation showed levels of approximately 10(9) CFU/mL in almost all sourdoughs and the comparison of the genetic polymorphisms of the dominating LAB with those of the pure cultures evidenced the persistence of the added strains over time. The resulting breads were evaluated for several quality parameters. The breads with the greatest height were obtained with the quadruple combination of leuconostocs and weissellas. The highest softness was registered for the breads obtained from fermentations performed by W. cibaria PON10032 alone and in combination. The different inocula influenced also the color, the void fraction, the cell density and the mean cell area of the breads. Different levels of acids, alcohols, aldehydes, esters, hydrocarbons, ketones, terpenes, furans and phenol were emitted by the breads. The sensory tests indicated the breads from the sourdoughs fermented with the seven LAB inocula as sweeter and less acidic than control breads and the breads from the trials with the highest complexity of LAB inoculums were those more appreciated by tasters. A multivariate approach found strong differences among the trials. In particular, control breads and the breads obtained with different starter LAB were quite distant and a more
Alvarez-Sieiro, Patricia; Redruello, Begoña; Ladero, Victor; Martín, Maria Cruz; Fernández, María; Alvarez, Miguel A
2016-05-01
A selective culture medium containing acid-hydrolyzed gliadins as the sole nitrogen source was used in the search for sourdough-indigenous lactic acid bacteria (LAB) with gliadin-metabolizing activity. Twenty gliadin-degrading LAB strains were isolated from 10 sourdoughs made in different ways and from different geographical regions. Fifteen of the 20 isolated strains were identified as Lactobacillus casei, a species usually reported as subdominant in sourdough populations. The other 5 gliadin-degrading strains belonged to the more commonly encountered sourdough species Leuconostoc mesenteroides and Lactobacillus plantarum. All these strains were shown to be safe in terms of their resistance to antimicrobial agents. When individually incubated with the α2-gliadin-derived immunotoxic 33-mer peptide (97.5 ppm), half of the L. casei strains metabolized at least 50% of it within 24 h. One strain metabolized 82% of the 33-mer peptide within 8 h and made it fully disappear within 12 h. These results reveal for the first time the presence in sourdough of proteolytic L. casei strains with the capacity to individually metabolize the coeliac-disease-related 33-mer peptide.
Matsuzaki, C; Kamishima, K; Matsumoto, K; Koga, H; Katayama, T; Yamamoto, K; Hisa, K
2014-04-01
The present work was aimed to find novel probiotics to enhance the mucosal barrier function of humans. The effectiveness was evaluated in vitro and in vivo. Stimulation of IgA production in mucosal surfaces is one of the most beneficial traits of lactic acid bacteria (LAB) for enhancing the barrier. Therefore, 173 LAB strains were evaluated for the ability to induce IgA production using murine Peyer's patch cells. Strain NTM048 isolated from green peas showed the highest activity and was identified as Leuconostoc mesenteroides subsp. mesenteroides. This strain was found to tolerate gastrointestinal digestion and produce large amounts of exopolysaccharides, which possess IgA-inducing activity. Dietary supplementation with NTM048 induced a significant increase in the faecal IgA content and plasma IgA levels of BALB/cA mice. A gene expression analysis of Peyer's patch cells revealed that the transforming growth factor-β and activation-induced cytidine deaminase genes were upregulated by NTM048 intake. Strain NTM048 stimulates Peyer's patch cells to induce intestinal and systemic immune response, revealing the potential of NTM048 as a probiotic for enhancing the mucosal barrier function. This report demonstrates a food-applicable Leuconostoc mesenteroides strain secreting exopolysaccharide that shows high IgA-inducing ability. © 2013 The Society for Applied Microbiology.
Bactericidal activities of GM flax seedcake extract on pathogenic bacteria clinical strains.
Zuk, Magdalena; Dorotkiewicz-Jach, Agata; Drulis-Kawa, Zuzanna; Arendt, Malgorzata; Kulma, Anna; Szopa, Jan
2014-07-29
The antibiotic resistance of pathogenic microorganisms is a worldwide problem. Each year several million people across the world acquire infections with bacteria that are antibiotic-resistant, which is costly in terms of human health. New antibiotics are extremely needed to overcome the current resistance problem. Transgenic flax plants overproducing compounds from phenylpropanoid pathway accumulate phenolic derivatives of potential antioxidative, and thus, antimicrobial activity. Alkali hydrolyzed seedcake extract containing coumaric acid, ferulic acid, caffeic acid, and lignan in high quantities was used as an assayed against pathogenic bacteria (commonly used model organisms and clinical strains). It was shown that the extract components had antibacterial activity, which might be useful as a prophylactic against bacterial infection. Bacteria topoisomerase II (gyrase) inhibition and genomic DNA disintegration are suggested to be the main reason for rendering antibacterial action. The data obtained strongly suggest that the seedcake extract preparation is a suitable candidate for antimicrobial action with a broad spectrum and partial selectivity. Such preparation can be applied in cases where there is a risk of multibacterial infection and excellent answer on global increase in multidrug resistance in pathogenic bacteria.
Pacheco da Rosa, Juliana; Korenblum, Elisa; Franco-Cirigliano, Marcella Novaes; Abreu, Fernanda; Lins, Ulysses; Soares, Rosângela M. A.; Macrae, Andrew; Seldin, Lucy; Coelho, Rosalie R. R.
2013-01-01
Four actinomycete strains previously isolated from Brazilian soils were tested for their antimicrobial activity against Bacillus pumilus LF-4 and Desulfovibrio alaskensis NCIMB 13491, bacteria that are well known to be involved in biofilm formation and biocorrosion. Strain 235, belonging to the species Streptomyces lunalinharesii, inhibited the growth of both bacteria. The antimicrobial activity was seen over a wide range of pH, and after treatment with several chemicals and heat but not with proteinase K and trypsin. The antimicrobial substances present in the concentrated supernatant from growth media were partially characterized by SDS-PAGE and extracellular polypeptides were seen. Bands in the size range of 12 to 14.4 kDa caused antimicrobial activity. Transmission electron microscopy of D. alaskensis cells treated with the concentrated supernatant containing the antimicrobial substances revealed the formation of prominent bubbles, the spherical double-layered structures on the cell membrane, and the periplasmic space completely filled with electron-dense material. This is the first report on the production of antimicrobial substances by actinomycetes against bacteria involved in biocorrosion processes, and these findings may be of great relevance as an alternative source of biocides to those currently employed in the petroleum industry. PMID:23484107
Paludan-Müller, C; Huss, H H; Gram, L
1999-02-18
Lactic acid bacteria (LAB) isolated from raw materials (fish, rice, garlic and banana leaves) and processed som-fak (a Thai low-salt fermented fish product) were characterized by API 50-CH and other phenotypic criteria. Lactococcus lactis subsp. lactis and Leuconostoc citreum were specifically associated with fish fillet and minced fish, Lactobacillus paracasei subsp. paracasei with boiled rice and Weisella confusa with garlic mix and banana leaves. In addition, Lactobacillus plantarum, Lactobacillus pentosus and Pediococcus pentosaceus were isolated from raw materials. A succession of aciduric, homofermentative lactobacillus species, dominated by Lb. plantarum/pentosus, was found during fermentation. In total, 9% of the strains fermented starch and 19% fermented garlic, the two main carbohydrate components in som-fak. The ability to ferment garlic was paralleled by a capacity to ferment inulin. An increased percentage of garlic fermenting strains was found during fermentation of som-fak, from 8% at day 1 to 40% at day 5. No starch fermenting strains were isolated during fermentation. Three mixed LAB cultures, composed of either starch fermenting Lc. lactis subsp. lactis and Lb. paracasei subsp. paracasei, or garlic fermenting Lb. plantarum and Pd. pentosaceus, or a combination of these strains were inoculated into laboratory prepared som-fak with or without garlic. In som-fak without garlic, pH was above 4.8 after three days, irrespective of addition of mixed LAB cultures. The starch fermenting LAB were unable to ferment som-fak and sensory spoilage occurred after three days. Fermentation with the combined mix of starch and garlic fermenting strains led to production of 2.5% acid and a decrease in pH to 4.5 in two days. The fermentation was slightly slower with the garlic fermenting strains alone. This is the first report describing the role of garlic as carbohydrate source for LAB in fermented fish products.
NASA Technical Reports Server (NTRS)
2003-01-01
Helen Cole, the project manager for the Lab-on-a-Chip Applications Development program, and Lisa Monaco, the project scientist for the program, insert a lab on a chip into the Caliper 42 which is specialized equipment that controls processes on commercial chips to support development of lab-on-a-chip applications. The system has special microscopes and imaging systems, so scientists can process and study different types of fluid, chemical, and medical tests conducted on chips. For example, researchers have examined fluorescent bacteria as it flows through the chips' fluid channels or microfluidic capillaries. Researchers at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama, have been studying how the lab-on-a-chip technology can be used for microbial detection, water quality monitoring, and detecting biosignatures of past or present life on Mars. The Marshall Center team is also collaborating with scientists at other NASA centers and at universities to develop custom chip designs for not only space applications, but for many Earth applications, such as for detecting deadly microbes in heating and air systems. (NASA/MSFC/D.Stoffer)
Daniel, C; Repa, A; Wild, C; Pollak, A; Pot, B; Breiteneder, H; Wiedermann, U; Mercenier, A
2006-07-01
Probiotic lactic acid bacteria (LAB) are able to modulate the host immune system and clinical trials have demonstrated that specific strains have the capacity to reduce allergic symptoms. Therefore, we aimed to evaluate the potential of recombinant LAB producing the major birch pollen allergen Bet v 1 for mucosal vaccination against birch pollen allergy. Recombinant Bet v 1-producing Lactobacillus plantarum and Lactococcus lactis strains were constructed. Their immunogenicity was compared with purified Bet v 1 by subcutaneous immunization of mice. Intranasal application of the live recombinant strains was performed to test their immunomodulatory potency in a mouse model of birch pollen allergy. Bet v 1 produced by the LAB was recognized by monoclonal anti-Bet v 1 and IgE antibodies from birch pollen-allergic patients. Systemic immunization with the recombinant strains induced significantly lower IgG1/IgG2a ratios compared with purified Bet v 1. Intranasal pretreatment led to reduced allergen-specific IgE vs enhanced IgG2a levels and reduced interleukin (IL)-5 production of splenocytes in vitro, indicating a shift towards non-allergic T-helper-1 (Th1) responses. Airway inflammation, i.e. eosinophils and IL-5 in lung lavages, was reduced using either Bet v 1-producing or control strains. Allergen-specific secretory IgA responses were enhanced in lungs and intestines after pretreatment with only the Bet v 1-producing strains. Mucosal vaccination with live recombinant LAB, leading to a shift towards non-allergic immune responses along with enhanced allergen-specific mucosal IgA levels offers a promising approach to prevent systemic and local allergic immune responses.
Konaté, Kiessoun; Hilou, Adama; Mavoungou, Jacques François; Lepengué, Alexis Nicaise; Souza, Alain; Barro, Nicolas; Datté, Jacques Y; M'batchi, Bertrand; Nacoulma, Odile Germaine
2012-02-24
The increased resistance of microorganisms to the currently used antimicrobials has lead to the evaluation of other agents that might have antimicrobial activity. Medicinal plants are sources of phytochemicals which are able to initiate different biological activities including antimicrobials In vitro antibacterial (MIC, MBC and time-kill studies) of polyphenol-rich fractions from Sida alba L. (Malvaceae) was assessed using ten bacteria strains (Gram-negative and Gram-positive). All test bacteria were susceptible to the polyphenol-rich fractions. Time-kill results showed that after 5 h exposition there was no viable microorganism in the initial inoculum and the effect of polyphenol-rich fractions was faster on Enterococcus faecalis (Gram-positive bacterium) comparatively to the other bacteria strains. The data analysis indicates that the tested of polyphenol-rich fractions has significant effects when compared with the standard antibiotic. These results therefore justify the traditional use of sida alba L., alone or in combination with other herbs to treat bacterial infections.
2012-01-01
Background The increased resistance of microorganisms to the currently used antimicrobials has lead to the evaluation of other agents that might have antimicrobial activity. Medicinal plants are sources of phytochemicals which are able to initiate different biological activities including antimicrobials Materials and methods In vitro antibacterial (MIC, MBC and time-kill studies) of polyphenol-rich fractions from Sida alba L. (Malvaceae) was assessed using ten bacteria strains (Gram-negative and Gram-positive). Results All test bacteria were susceptible to the polyphenol-rich fractions. Time-kill results showed that after 5 h exposition there was no viable microorganism in the initial inoculum and the effect of polyphenol-rich fractions was faster on Enterococcus faecalis (Gram-positive bacterium) comparatively to the other bacteria strains. Conclusion The data analysis indicates that the tested of polyphenol-rich fractions has significant effects when compared with the standard antibiotic. These results therefore justify the traditional use of sida alba L., alone or in combination with other herbs to treat bacterial infections. PMID:22364123
Nowak, Adriana; Śliżewska, Katarzyna; Otlewska, Anna
2015-12-01
Dietary components such as lactic acid bacteria (LAB) and prebiotics can modulate the intestinal microbiota and are thought to be involved in the reduction of colorectal cancer risk. The presented study measured, using the comet assay, the antigenotoxic activity of both probiotic and non-probiotic LAB, as well as some prebiotics and the end-products of their fermentation, against fecal water (FW). The production of short chain fatty acids by the bacteria was quantified using HPLC. Seven out of the ten tested viable strains significantly decreased DNA damage induced by FW. The most effective of them were Lactobacillus mucosae 0988 and Bifidobacterium animalis ssp. lactis Bb-12, leading to a 76% and 80% decrease in genotoxicity, respectively. The end-products of fermentation of seven prebiotics by Lactobacillus casei DN 114-001 exhibited the strongest antigenotoxic activity against FW, with fermented inulin reducing genotoxicity by 75%. Among the tested bacteria, this strain produced the highest amounts of butyrate in the process of prebiotic fermentation, and especially from resistant dextrin (4.09 μM/mL). Fermented resistant dextrin improved DNA repair by 78% in cells pre-treated with 6.8 μM methylnitronitrosoguanidine (MNNG). Fermented inulin induced stronger DNA repair in cells pre-treated with mutagens (FW, 25 μM hydrogen peroxide, or MNNG) than non-fermented inulin, and the efficiency of DNA repair after 120 min of incubation decreased by 71%, 50% and 70%, respectively. The different degrees of genotoxicity inhibition observed for the various combinations of bacteria and prebiotics suggest that this effect may be attributable to carbohydrate type, SCFA yield, and the ratio of the end-products of prebiotic fermentation. Copyright © 2015 Elsevier Inc. All rights reserved.
Gomółka-Pawlicka, M; Uradziński, J; Wiszniewska, A
2004-01-01
The present study was aimed at determining the influence of 15 strains of lactic acid bacteria on the growth of 2 Staphylococcus aureus strains in vitro as well as in meat and raw sausages. The investigations were performed within the framework of three alternate stages which differed in respect to the products studied, the number of Lactobacillus sp. strains and, partly, methodological approach. The study also considered water activity (a(w)) and pH of the products investigated. The results obtained are demonstrated in 5 diagrams. It was found that among 15 strains of Lactobacillus aureus investigated only one strain, Lactobacillus helveticus T 78, showed antagonistic effect on studied strains of Staphylococcus aureus both in vitro as well as in meat and raw sausages. Five other strains of Lactobacillus spp. displayed the antagonistic effect in vitro only. The temperature and incubation time of sausages, but also the type of sausage stuffing were found to have a distinct or slight influence, respectively, on the antagonistic interaction between the bacteria. However, this phenomenon was affected by neither a(w) nor pH.
Elizaquível, P; Sánchez, G; Salvador, A; Fiszman, S; Dueñas, M T; López, P; Fernández de Palencia, P; Aznar, R
2011-07-01
Probiotic cultures are increasingly being incorporated into a wide variety of food products. Although lactobacilli and bifidobacteria are the most frequently used, other lactic acid bacteria (LAB) have been reported to be potential probiotics. Of these, the cider isolates Pediococccus parvulus (strains 2.6 and CUPV22) and Lactobacillus suebicus CUPV221 produce a 2-branched (1,3)-β-d-glucan exopolysaccharide that decreases serum cholesterol levels and affects the activation of human macrophages. For this reason, these 3 strains were incorporated into yogurt, orange juice, and 2 juice-milk beverages to evaluate the effect of the food matrix on the resistance of these strains to simulated gastrointestinal tract conditions. Our results showed that incorporation of the LAB did not significantly affect the physical and rheological properties of the food matrices tested. When incorporated in yogurt, LAB strains population decreased by 2 to 3 log orders of magnitude during the shelf life of the product (28 d). However, no significant decrease was observed in the juice and juice-milk beverages during the same storage period, except for Lb. suebicus, whose viability decreased by 3 log orders of magnitude. When strains were subjected to gastrointestinal tract conditions, a decrease in the survival was observed at the lower pH (1.8). However, incorporation of these LAB strains into orange juice increases their resistance to lower pH conditions, thus improving survival to gastrointestinal stress. Moreover, a protective effect was observed for P. parvulus CUPV22 and 2.6 to gastric stress in juice-milk beverages and to gastrointestinal stress in yogurt. Lactobacillus suebicus CUPV221 did not survive when incorporated into yogurt and juice-milk beverage. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
Bartkiene, Elena; Krungleviciute, Vita; Juodeikiene, Grazina; Vidmantiene, Daiva; Maknickiene, Zita
2015-04-01
The ability of bacteriocin-like inhibitory substance (BLIS)-producing lactic acid bacteria (LAB) to degrade biogenic amines as well as to produce L(+) and D(-)-lactic acid during solid state fermentation (SSF) of lupin and soya bean was investigated. In addition, the protein digestibility and formation of organic acids during SSF of legume were investigated. Protein digestibility of fermented lupin and soya bean was found higher on average by 18.3% and 15.9%, respectively, compared to untreated samples. Tested LAB produced mainly L-lactic acid in soya bean and lupin (D/L ratio 0.38-0.42 and 0.35-0.54, respectively), while spontaneous fermentation gave almost equal amounts of both lactic acid isomers (D/L ratio 0.82-0.98 and 0.92, respectively). Tested LAB strains were able to degrade phenylethylamine, spermine and spermidine, whereas they were able to produce putrescine, histamine and tyramine. SSF improved lupin and soya bean protein digestibility. BLIS-producing LAB in lupin and soya bean medium produced a mixture of D- and L-lactic acid with a major excess of the latter isomer. Most toxic histamine and tyramine in fermented lupin and soya bean were found at levels lower those causing adverse health effects. Selection of biogenic amines non-producing bacteria is essential in the food industry to avoid the risk of amine formation. © 2014 Society of Chemical Industry.
Zhou, Xin-Wei; Zhao, Xin-Huai
2015-01-01
Previous research has shown that fresh milk might be polluted by some organophosphorus pesticides (OPPs). In this study the dissipation of nine OPPs, namely chlorpyrifos, chlorpyrifos-methyl, diazinon, dichlorvos, fenthion, malathion, phorate, pirimiphos-methyl and trichlorphon, in skimmed milk was investigated to clarify their susceptibility towards lactic acid bacteria (LAB) and yogurt starters. Skimmed milk was spiked with nine OPPs, inoculated with five strains of LAB and two commercial yogurt starters at 42 °C for 24 and 5 h respectively and subjected to quantitative OPP analysis by gas chromatography. Degradation kinetic constants of these OPPs were calculated based on a first-order reaction model. OPP dissipation in the milk was enhanced by the inoculated strains and starters, resulting in OPP concentrations decreasing by 7.0-64.6 and 7.4-19.2% respectively. Totally, the nine OPPs were more susceptible to Lactobacillus bulgaricus, as it enhanced their degradation rate constants by 18.3-133.3%. Higher phosphatase production of the assayed stains was observed to bring about greater OPP degradation in the milk. Both LAB and yogurt starters could enhance OPP dissipation in skimmed milk, with the nine OPPs studied having different susceptibilities towards them. Phosphatase was a key factor governing OPP dissipation. The LAB of higher phosphatase production have more potential to decrease OPPs in fermented foods. © 2014 Society of Chemical Industry.
Randazzo, C L; De Luca, S; Todaro, A; Restuccia, C; Lanza, C M; Spagna, G; Caggia, C
2007-08-01
The aim of this work was to preliminary characterize wild lactic acid bacteria (LAB), previously isolated during artisanal Pecorino Siciliano (PS) cheese-making for technological and flavour formation abilities in a model cheese system. Twelve LAB were studied for the ability to grow at 10 and 45 degrees C, to coagulate and acidify both reconstituted skim milk and ewe's milk. Moreover, the capacity of the strains to generate aroma compounds was evaluated in a model cheese system at 30- and 60-day ripening. Flavour compounds were screened by sensory analysis and throughout gas chromatography (GC)-mass spectrometry (MS). Most of the strains were able to grow both at 10 and 45 degrees C and exhibited high ability to acidify and coagulate ewes' milk. Sensory evaluation revealed that the wild strains produced more significant flavour attributes than commercial strains in the 60-day-old model cheese system. GC-MS data confirmed the results of sensory evaluations and showed the ability of wild lactobacilli to generate key volatile compounds. Particularly, three wild lactobacilli strains, belonging to Lactobacillus casei, Lb. rhamnosus and Lb. plantarum species, generated both in 60- and 30-day-old model cheeses system, the 3-methyl butan(al)(ol) compound, which is associated with fruity taste. The present work preliminarily demonstrated that the technological and flavour formation abilities of the wild strains are strain-specific and that wild lactobacilli, which produced key flavour compounds during ripening, could be used as tailor-made starters. This study reports the technological characterization and flavour formation ability of wild LAB strains isolated from artisanal Pecorino cheese and highlights that the catabolic activities were highly strain dependent. Hence, wild lactobacilli could be selected as tailor-made starter cultures for the PS cheese manufacture.
Review - Lactic acid bacteria in traditional fermented Asian foods.
Azam, Mariya; Mohsin, Mashkoor; Ijaz, Hira; Tulain, Ume Ruqia; Ashraf, Muhammad Adnan; Fayyaz, Ahad; Abadeen, Zainul; Kamran, Qindeel
2017-09-01
Lactic acid bacteria play vital roles in various fermented foods in Asia. This paper reviews many types of the world's lactic acid fermented foods and discusses the beneficial effects of lactic acid fermentation of food. The lactic acid bacteria associated with foods now include species of the genera Carnobacterium, Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Oenococcus, Pediococcus, Streptococcus, Tetragenococcus, Vagococcus and Weissella. Lactic acid bacteria (LAB) are involved in many fermentation processes of Asian traditional foods, demonstrating their profound effects on improving food quality and food safety. During the past few decades' interest has arisen in the use of the varied antagonistic activities of LAB to extent the shelf-life of protein-rich products such as meats and fish. This review article outlines the main types of LAB fermentation as well as their typical fermented foods such as idli, kishk, sauerkraut, koumiss, Suan-tsai, stinky tofu, Chinese sausage and kefir. The roles of LAB and the reasons for their common presence are also discussed.
Fernández-Pérez, Rocío; Torres, Carmen; Sanz, Susana; Ruiz-Larrea, Fernanda
2010-12-01
Strain typing of 103 acetic acid bacteria isolates from vinegars elaborated by the submerged method from ciders, wines and spirit ethanol, was carried on in this study. Two different molecular methods were utilised: pulsed field gel electrophoresis (PFGE) of total DNA digests with a number of restriction enzymes, and enterobacterial repetitive intergenic consensus (ERIC) - PCR analysis. The comparative study of both methods showed that restriction fragment PFGE of SpeI digests of total DNA was a suitable method for strain typing and for determining which strains were present in vinegar fermentations. Results showed that strains of the species Gluconacetobacter europaeus were the most frequent leader strains of fermentations by the submerged method in the studied vinegars, and among them strain R1 was the predominant one. Results showed as well that mixed populations (at least two different strains) occurred in vinegars from cider and wine, whereas unique strains were found in spirit vinegars, which offered the most stressing conditions for bacterial growth. Copyright © 2010 Elsevier Ltd. All rights reserved.
Solieri, Lisa; Giudici, Paolo
2010-01-01
Control over malolactic fermentation (MLF) is a difficult goal in winemaking and needs rapid methods to monitor Oenococcus oeni malolactic starters (MLS) in a stressful environment such as wine. In this study, we describe a novel quantitative PCR (QPCR) assay enabling the detection of an O. oeni strain during MLF without culturing. O. oeni strain LB221 was used as a model to develop a strain-specific sequence-characterized amplified region (SCAR) marker derived from a discriminatory OPA20-based randomly amplified polymorphic DNA (RAPD) band. The 5′ and 3′ flanking regions and the copy number of the SCAR marker were characterized using inverse PCR and Southern blotting, respectively. Primer pairs targeting the SCAR sequence enabled strain-specific detection without cross amplification of other O. oeni strains or wine species of lactic acid bacteria (LAB), acetic acid bacteria (AAB), and yeasts. The SCAR-QPCR assay was linear over a range of cell concentrations (7 log units) and detected as few as 2.2 × 102 CFU per ml of red wine with good quantification effectiveness, as shown by the correlation of QPCR and plate counting results. Therefore, the cultivation-independent monitoring of a single O. oeni strain in wine based on a SCAR marker represents a rapid and effective strain-specific approach. This strategy can be adopted to develop easy and rapid detection techniques for monitoring the implantation of inoculated O. oeni MLS on the indigenous LAB population, reducing the risk of unsuccessful MLF. PMID:20935116
Zheng, Yu; Mou, Jun; Niu, Jiwei; Yang, Shuai; Chen, Lin; Xia, Menglei; Wang, Min
2018-03-01
Lactic acid bacteria (LAB) are essential microbiota for the fermentation and flavor formation of Shanxi aged vinegar, a famous Chinese traditional cereal vinegar that is manufactured using open solid-state fermentation (SSF) technology. However, the dynamics of LAB in this SSF process and the underlying mechanism remain poorly understood. Here, the diversity of LAB and the potential driving factors of the entire process were analyzed by combining culture-independent and culture-dependent methods. Canonical correlation analysis indicated that ethanol, acetic acid, and temperature that result from the metabolism of microorganisms serve as potential driving factors for LAB succession. LAB strains were periodically isolated, and the characteristics of 57 isolates on environmental factor tolerance and substrate utilization were analyzed to understand the succession sequence. The environmental tolerance of LAB from different stages was in accordance with their fermentation conditions. Remarkable correlations were identified between LAB growth and environmental factors with 0.866 of ethanol (70 g/L), 0.756 of acetic acid (10 g/L), and 0.803 of temperature (47 °C). More gentle or harsh environments (less or more than 60 or 80 g/L of ethanol, 5 or 20 g/L of acetic acid, and 30 or 55 °C temperature) did not affect the LAB succession. The utilization capability evaluation of the 57 isolates for 95 compounds proved that strains from different fermentation stages exhibited different predilections on substrates to contribute to the fermentation at different stages. Results demonstrated that LAB succession in the SSF process was driven by the capabilities of environmental tolerance and substrate utilization.
Genomics of Probiotic Bacteria
NASA Astrophysics Data System (ADS)
O'Flaherty, Sarah; Goh, Yong Jun; Klaenhammer, Todd R.
Probiotic bacteria from the Lactobacillus and Bifidobacterium species belong to the Firmicutes and the Actinobacteria phylum, respectively. Lactobacilli are members of the lactic acid bacteria (LAB) group, a broadly defined family of microorganisms that ferment various hexoses into primarily lactic acid. Lactobacilli are typically low G + C gram-positive species which are phylogenetically diverse, with over 100 species documented to date. Bifidobacteria are heterofermentative, high G + C content bacteria with about 30 species of bifidobacteria described to date.
Kojima, Ayuchi; Nakano, Kazuhiko; Wada, Koichiro; Takahashi, Hirokazu; Katayama, Kazufumi; Yoneda, Masato; Higurashi, Takuma; Nomura, Ryota; Hokamura, Kazuya; Muranaka, Yoshinori; Matsuhashi, Nobuyuki; Umemura, Kazuo; Kamisaki, Yoshinori; Nakajima, Atsushi; Ooshima, Takashi
2012-01-01
Although oral bacteria-associated systemic diseases have been reported, association between Streptococcus mutans, pathogen of dental caries, and ulcerative colitis (UC) has not been reported. We investigated the effect of various S. mutans strains on dextran sodium sulfate (DSS)-induced mouse colitis. Administration of TW295, the specific strain of S. mutans, caused aggravation of colitis; the standard strain, MT8148 did not. Localization of TW295 in hepatocytes in liver was observed. Increased expression of interferon-γ in liver was also noted, indicating that the liver is target organ for the specific strain of S. mutans-mediated aggravation of colitis. The detection frequency of the specific strains in UC patients was significantly higher than in healthy subjects. Administration of the specific strains of S. mutans isolated from patients caused aggravation of colitis. Infection with highly-virulent specific types of S. mutans might be a potential risk factor in the aggravation of UC. PMID:22451861
Nardin, Tiziana; Schiavon, Silvia; Cavazza, Agostino; Larcher, Roberto; Tuohy, Kieran M.
2015-01-01
“Nostrano-cheeses” are traditional alpine cheeses made from raw cow's milk in Trentino-Alto Adige, Italy. This study identified lactic acid bacteria (LAB) developing during maturation of “Nostrano-cheeses” and evaluated their potential to produce γ-aminobutyric acid (GABA), an immunologically active compound and neurotransmitter. Cheese samples were collected on six cheese-making days, in three dairy factories located in different areas of Trentino and at different stages of cheese ripening (24 h, 15 days, and 1, 2, 3, 6, and 8 months). A total of 1,059 LAB isolates were screened using Random Amplified Polymorphic DNA-PCR (RAPD-PCR) and differentiated into 583 clusters. LAB strains from dominant clusters (n = 97) were genetically identified to species level by partial 16S rRNA gene sequencing. LAB species most frequently isolated were Lactobacillus paracasei, Streptococcus thermophilus, and Leuconostoc mesenteroides. The 97 dominant clusters were also characterized for their ability in producing GABA by high-performance liquid chromatography (HPLC). About 71% of the dominant bacteria clusters evolving during cheeses ripening were able to produce GABA. Most GABA producers were Lactobacillus paracasei but other GABA producing species included Lactococcus lactis, Lactobacillus plantarum, Lactobacillus rhamnosus, Pediococcus pentosaceus, and Streptococcus thermophilus. No Enterococcus faecalis or Sc. macedonicus isolates produced GABA. The isolate producing the highest amount of GABA (80.0±2.7 mg/kg) was a Sc. thermophilus. PMID:25802859
Franciosi, Elena; Carafa, Ilaria; Nardin, Tiziana; Schiavon, Silvia; Poznanski, Elisa; Cavazza, Agostino; Larcher, Roberto; Tuohy, Kieran M
2015-01-01
"Nostrano-cheeses" are traditional alpine cheeses made from raw cow's milk in Trentino-Alto Adige, Italy. This study identified lactic acid bacteria (LAB) developing during maturation of "Nostrano-cheeses" and evaluated their potential to produce γ-aminobutyric acid (GABA), an immunologically active compound and neurotransmitter. Cheese samples were collected on six cheese-making days, in three dairy factories located in different areas of Trentino and at different stages of cheese ripening (24 h, 15 days, and 1, 2, 3, 6, and 8 months). A total of 1,059 LAB isolates were screened using Random Amplified Polymorphic DNA-PCR (RAPD-PCR) and differentiated into 583 clusters. LAB strains from dominant clusters (n = 97) were genetically identified to species level by partial 16S rRNA gene sequencing. LAB species most frequently isolated were Lactobacillus paracasei, Streptococcus thermophilus, and Leuconostoc mesenteroides. The 97 dominant clusters were also characterized for their ability in producing GABA by high-performance liquid chromatography (HPLC). About 71% of the dominant bacteria clusters evolving during cheeses ripening were able to produce GABA. Most GABA producers were Lactobacillus paracasei but other GABA producing species included Lactococcus lactis, Lactobacillus plantarum, Lactobacillus rhamnosus, Pediococcus pentosaceus, and Streptococcus thermophilus. No Enterococcus faecalis or Sc. macedonicus isolates produced GABA. The isolate producing the highest amount of GABA (80.0±2.7 mg/kg) was a Sc. thermophilus.
Khota, Waroon; Pholsen, Suradej; Higgs, David; Cai, Yimin
2017-01-01
Objective The effects of lactic acid bacteria (LAB) and cellulase enzyme on fermentation quality, microorganism population, chemical composition and in vitro gas production of sorghum silages were studied. Methods Commercial inoculant Lactobacillus plantarum Chikuso 1 (CH), local selected strain Lactobacillus casei (L. casei) TH 14 and Acremonium cellulase (AC) were used as additives in sorghum silage preparation. Results Prior to ensiling Sorghum contained 104 LAB and 106 cfu/g fresh matter coliform bacteria. The chemical compositions of sorghum was 26.6% dry matter (DM), 5.2% crude protein (CP), and 69.7% DM for neutral detergent fiber. At 30 days of fermentation after ensiling, the LAB counts increased to a dominant population; the coliform bacteria and molds decreased to below detectable level. All sorghum silages were good quality with a low pH (<3.5) and high lactic acid content (>66.9 g/kg DM). When silage was inoculated with TH14, the pH value was significantly (p<0.05) lower and the CP content significantly (p<0.05) higher compared to control, CH and AC-treatments. The ratio of in vitro methane production to total gas production and DM in TH 14 and TH 14+AC treatments were significantly (p<0.05) reduced compared with other treatments while in vitro dry matter digestibility and gas production did not differ among treatments. Conclusion The results confirmed that L. casei TH14 could improve sorghum silage fermentation, inhibit protein degradation and decrease methane production. PMID:28728399
In Vitro Activities of Faropenem against 579 Strains of Anaerobic Bacteria
Wexler, Hannah M.; Molitoris, Denise; St. John, Shahera; Vu, Ann; Read, Erik K.; Finegold, Sydney M.
2002-01-01
The activity of faropenem, a new oral penem, was tested against 579 strains of anaerobic bacteria by using the NCCLS-approved reference method. Drugs tested included amoxicillin-clavulanate, cefoxitin, clindamycin, faropenem, imipenem, and metronidazole. Of the 176 strains of Bacteroides fragilis group isolates tested, two isolates had faropenem MICs of 64 μg/ml and imipenem MICs of >32 μg/ml. Faropenem had an MIC of 16 μg/ml for an additional isolate of B. fragilis; this strain was sensitive to imipenem (MIC of 1 μg/ml). Both faropenem and imipenem had MICs of ≤4 μg/ml for all isolates of Bacteroides capillosus (10 isolates), Bacteroides splanchnicus (13 isolates), Bacteroides ureolyticus (11 isolates), Bilophila wadsworthia (11 isolates), Porphyromonas species (42 isolates), Prevotella species (78 isolates), Campylobacter species (25 isolates), Sutterella wadsworthensis (11 isolates), Fusobacterium nucleatum (19 isolates), Fusobacterium mortiferum/varium (20 isolates), and other Fusobacterium species (9 isolates). Faropenem and imipenem had MICs of 16 to 32 μg/ml for two strains of Clostridium difficile; the MICs for all other strains of Clostridium tested (69 isolates) were ≤4 μg/ml. Faropenem had MICs of 8 and 16 μg/ml, respectively, for two strains of Peptostreptococcus anaerobius (MICs of imipenem were 2 μg/ml). MICs were ≤4 μg/ml for all other strains of gram-positive anaerobic cocci (53 isolates) and non-spore-forming gram-positive rods (28 isolates). Other results were as expected and reported in previous studies. No metronidazole resistance was seen in gram-negative anaerobes other than S. wadsworthensis (18% resistant); 63% of gram-positive non-spore-forming rods were resistant. Some degree of clindamycin resistance was seen in most of the groups tested. PMID:12384389
Chang, Chiung-Hung; Chen, Yueh-Sheng; Chiou, Ming-Tang; Su, Chiu-Hsian; Chen, Daniel S.; Tsai, Chin-En; Yu, Bi; Hsu, Yuan-Man
2013-01-01
Salmonella enterica serovar Choleraesuis, a host-adapted pathogen of swine, usually causes septicemia. Lactic acid bacteria (LAB) strains have been widely studied in recent years for their probiotic properties. In this study, a mouse infection model first screened for potential agents against infection, then a pig infection model evaluated effects of LAB strains and herbal plants against infection. Scutellariae radix (SR) and Gardeniae fructus (GF) showed abilities to reduce bacteria shedding and suppressing serum level of TNF-α induced by infection in swine. Bioactivities of SR and GF were enhanced by combining with LAB strains, which alone could speed up the bacteria elimination time in feces and boost immunity of infected pigs. Baicalein and genipin exhibited stronger cytotoxicity than baicalin and geniposide did, as well as prevent Salmonella from invading macrophages. Our study suggests LAB strains as exhibiting multiple functions: preventing infection, enhancing immunity to prepare host defenses against further infection, and adjusting intestinal microbes' enzymatic activity in order to convert herbal compounds to active compounds. The SR/GF-LAB strain mixture holds potential infection-prevention agents supplied as feed additives. PMID:23533497
Feutry, Fabienne; Oneca, María; Berthier, Françoise; Torre, Paloma
2012-02-01
The biodiversity and growth dynamics of Lactic Acid Bacteria (LAB) in farm-house Ossau-Iraty cheeses were investigated from vat milk to 180 days of ripening in six independent batches made from six raw ewe's milks using five typical cheese-making methods. Commercial starter S1 was used for three batches, starter S1 combined with S2 for one batch and no starter for two batches. Up to ten LAB species from five genera and up to two strains per species were identified per milk; up to eleven species from five genera and up to three strains per species were identified per cheese. Lactococcus lactis, Lactobacillus paracasei, Enterococcus faecalis, Enterococcus faecium, Enterococcus durans, and Leuconostoc mesenteroides were detected in all cheeses. Lactococci reached the highest counts irrespective of the milk and starter used. Lactococci and enterococci increased during manufacture, and mesophilic lactobacilli increased during ripening. Strain and species numbers, the percentage of isolates originating from the raw milk, maximum counts of each genus/species and time for reaching them, all varied according to whether or not a starter was used and the composition of the starter. The genotypes of strains within species varied according to the raw milk used. This generated distinct LAB microbiotas throughout manufacture and ripening that will certainly impact on the characteristics of the ripened cheeses. Copyright © 2011 Elsevier Ltd. All rights reserved.
Symbiotic relationship analysis of predominant bacteria in a lab-scale anammox UASB bioreactor.
Wang, Yujia; Hu, Xiaomin; Jiang, Binhui; Song, Zhenhui; Ma, Yongguang
2016-04-01
In order to provide the comprehensive insight into the key microbial groups in anaerobic ammonium oxidation (anammox) process, high-throughput sequencing analysis has been used for the investigation of the bacterial communities of a lab-scale upflow anaerobic sludge bed (UASB) anammox bioreactor. Results revealed that 109 operational taxonomic units (OTUs; out of 14,820 reads) were identified and a domination of anammox bacteria of Candidatus Kuenenia stuttgartiensis (OTU474, 35.42 %), along with heterotrophs of Limnobacter sp. MED105 (OTU951, 14.98 %), Anerolinea thermophila UNI-1 (OTU465 and OTU833, 6.60 and 3.93 %), Azoarcus sp. B72 (OTU26, 9.47 %), and Ignavibacterium sp. JCM 16511 (OTU459, 8.33 %) were detected. Metabolic pathway analysis showed that Candidatus K. stuttgartiensis encountered gene defect in synthesizing a series of metabolic cofactors for growth, implying that K. stuttgartiensis is auxotrophic. Coincidentally, the other dominant species severally showed complete metabolic pathways with full set gene encoding to corresponding cofactors presented in the surrounding environment. Furthermore, it was likely that the survival of heterotrophs in the autotrophic system indicates the existence of a symbiotic and mutual relationship in anammox system.
Narisawa, Naoki; Haruta, Shin; Arai, Hiroyuki; Ishii, Masaharu; Igarashi, Yasuo
2008-06-01
Antibiotic-sensitive bacteria have been found to coexist with antibiotic-producing bacteria in biofilms, but little is known about how the former develop in such an environment. Here we isolated pyocyanin-sensitive bacteria belonging to the genus Brevibacillus from a biofilm derived from soil extract and based on the preestablished biofilm of a pyocyanin producer, Pseudomonas aeruginosa strain P1. In addition, pyocyanin-resistant strains belonging to the genus Raoultella were isolated from the same biofilm. Microbial relationships within biofilms were examined by using three strains, strain P1, Brevibacillus strain S1, and Raoultella strain R1, each of which individually formed a biofilm within 2 days in a flow cell. Strain S1 did not fully develop on the preestablished biofilm of strain P1 during 4 days of cultivation, whereas a mutant of strain P1 which was deficient in pyocyanin production allowed strain S1 to cocolonize within a biofilm. On the other hand, strain R1 developed on the biofilm of strain P1 regardless of pyocyanin production. When mixed 1:1 inocula of strains S1 and R1 were introduced into the strain P1 biofilm, all three species were found in the 4-day biofilm. In the mixed biofilm, strain S1 was surrounded by the layer of strain R1 and seemed to be separated from strain P1 and the outflow solution. However, strain S1 did not survive in a three-species mixed culture under planktonic conditions. These results indicate that the survival of sensitive bacteria in biofilm with a pyocyanin producer is achieved by covering them with a layer of resistant bacteria. We also evaluated the influence of antibiotic production on the producer.
Ventimiglia, Giusi; Alfonzo, Antonio; Galluzzo, Paola; Corona, Onofrio; Francesca, Nicola; Caracappa, Santo; Moschetti, Giancarlo; Settanni, Luca
2015-10-01
Fifteen sourdoughs produced in western Sicily (southern Italy) were analysed by classical methods for their chemico-physical characteristics and the levels of lactic acid bacteria (LAB). pH and total titratable acidity (TTA) were mostly in the range commonly reported for similar products produced in Italy, but the fermentation quotient (FQ) of the majority of samples was above 4.0, due to the low concentration of acetic acid estimated by high performance liquid chromatography (HPLC). Specific counts of LAB showed levels higher than 10(8) CFU g(-1) for many samples. The colonies representing various morphologies were isolated and, after the differentiation based on phenotypic characteristics, divided into 10 groups. The most numerous group was composed of facultative heterofermentative isolates, indicating a relevance of this bacterial group during fermentation. The genetic analysis by randomly amplified polymorphic DNA (RAPD)-PCR, 16S rRNA gene sequencing and species-specific PCRs identified 33 strains as Lactobacillus plantarum, Lactobacillus curvatus and Lactobacillus graminis. Due to the consistent presence of L. plantarum, it was concluded that this species codominates with obligate heterofermentative LAB in sourdough production in this geographical area. In order to evaluate the performances at the basis of their fitness, the 29 L. plantarum strains were investigated for several technological traits. Twelve cultures showed good acidifying abilities in vitro and L. plantarum PON100148 produced the highest concentrations of organic acids. Eleven strains were positive for extracellular protease activity. Bacteriocin-like inhibitory substances (BLIS) production and antifungal activity was scored positive for several strains, included L. plantarum PON100148 which was selected as starter for experimental sourdough production. The characteristics of the sourdoughs and the resulting breads indicated that the best productions were obtained in presence of L
USDA-ARS?s Scientific Manuscript database
Lactic acid bacteria (LAB) have been widely used in the production of fermented foods and as probiotics. Alternan is a glucan with a distinctive backbone structure of alternating a-(1,6) and a-(1,3) linkages produced by the LAB Leuconostoc mesenteroides. In recent years, we have developed improved...
Interactions between Cooccurring Lactic Acid Bacteria in Honey Bee Hives
Rokop, Z. P.; Horton, M. A.
2015-01-01
In contrast to the honey bee gut, which is colonized by a few characteristic bacterial clades, the hive of the honey bee is home to a diverse array of microbes, including many lactic acid bacteria (LAB). In this study, we used culture, combined with sequencing, to sample the LAB communities found across hive environments. Specifically, we sought to use network analysis to identify microbial hubs sharing nearly identical operational taxonomic units, evidence which may indicate cooccurrence of bacteria between environments. In the process, we identified interactions between noncore bacterial members (Fructobacillus and Lactobacillaceae) and honey bee-specific “core” members. Both Fructobacillus and Lactobacillaceae colonize brood cells, bee bread, and nectar and may serve the role of pioneering species, establishing an environment conducive to the inoculation by honey bee core bacteria. Coculture assays showed that these noncore bacterial members promote the growth of honey bee-specific bacterial species. Specifically, Fructobacillus by-products in spent medium supported the growth of the Firm-5 honey bee-specific clade in vitro. Metabolic characterization of Fructobacillus using carbohydrate utilization assays revealed that this strain is capable of utilizing the simple sugars fructose and glucose, as well as the complex plant carbohydrate lignin. We tested Fructobacillus for antibiotic sensitivity and found that this bacterium, which may be important for establishment of the microbiome, is sensitive to the commonly used antibiotic tetracycline. Our results point to the possible significance of “noncore” and environmental microbial community members in the modulation of honey bee microbiome dynamics and suggest that tetracycline use by beekeepers should be limited. PMID:26253685
Adler, Philipp; Bolten, Christoph Josef; Dohnt, Katrin; Hansen, Carl Erik
2013-01-01
In the present work, simulated cocoa fermentation was investigated at the level of metabolic pathway fluxes (fluxome) of lactic acid bacteria (LAB), which are typically found in the microbial consortium known to convert nutrients from the cocoa pulp into organic acids. A comprehensive 13C labeling approach allowed to quantify carbon fluxes during simulated cocoa fermentation by (i) parallel 13C studies with [13C6]glucose, [1,2-13C2]glucose, and [13C6]fructose, respectively, (ii) gas chromatography-mass spectrometry (GC/MS) analysis of secreted acetate and lactate, (iii) stoichiometric profiling, and (iv) isotopomer modeling for flux calculation. The study of several strains of L. fermentum and L. plantarum revealed major differences in their fluxes. The L. fermentum strains channeled only a small amount (4 to 6%) of fructose into central metabolism, i.e., the phosphoketolase pathway, whereas only L. fermentum NCC 575 used fructose to form mannitol. In contrast, L. plantarum strains exhibited a high glycolytic flux. All strains differed in acetate flux, which originated from fractions of citrate (25 to 80%) and corresponding amounts of glucose and fructose. Subsequent, metafluxome studies with consortia of different L. fermentum and L. plantarum strains indicated a dominant (96%) contribution of L. fermentum NCC 575 to the overall flux in the microbial community, a scenario that was not observed for the other strains. This highlights the idea that individual LAB strains vary in their metabolic contribution to the overall fermentation process and opens up new routes toward streamlined starter cultures. L. fermentum NCC 575 might be one candidate due to its superior performance in flux activity. PMID:23851099
Biscola, V; Choiset, Y; Rabesona, H; Chobert, J-M; Haertlé, T; Franco, B D G M
2018-04-13
The objective was to obtain lactic acid bacteria (LAB) capable of hydrolysing immunoreactive proteins in milk, to optimize the hydrolysis, to determine the proteolysis kinetics and to test the safety of the best hydrolytic strain. Brazilian cheese was used as source of LAB capable of hydrolysing main milk allergens. Proteolytic isolates were submitted to RAPD-PCR for the characterization of clonal diversity. Optimized hydrolysis was strain and protein fraction dependent. 16S rDNA sequencing identified three proteolytic strains: Enterococcus faecalis VB43, that hydrolysed α S1 -, α S2 - and β-caseins, α-lactalbumin and β-lactoglobulin (partial hydrolysis), and Pediococcus acidilactici VB90 and Weissella viridescens VB111, that caused partial hydrolysis of α S1 - and α S2 -caseins. Enterococcus faecalis VB43 tested negative for virulence genes asa1, agg, efaA, hyl, esp, cylL L and cylL S but positive for genes ace and gelE. Ethylenediamine tetra-acetic acid inhibited the proteolysis, indicating that the main proteases of E. faecalis VB43 are metalloproteases. Brazilian artisanal cheese is a good source of LAB capable of hydrolysing allergenic proteins in milk. One isolate (E. faecalis VB43) presented outstanding activity against these proteins and lacked most of the tested virulence genes. Enterococcus faecalis VB43 presents good potential for the manufacture of hypoallergenic dairy products. © 2018 The Society for Applied Microbiology.
Screening and biological characteristics of fufenozide degrading bacteria
NASA Astrophysics Data System (ADS)
Xu, Chenhao; Gong, Mingfu; Guan, Qinlan; Deng, Xia; Deng, Hongyan; Huang, Jiao
2018-04-01
Fufenozide was a novel pesticide for the control of Lepidoptera pests, which was highly toxic to silkworm. Fufenozide-contaminated soil samples were collected and the bacteria that degrade fufenozide were isolated and screened by selective medium. The colony characteristics, cell characteristics and degradation characteristics in different concentrations fufenozide of the fufenozide degrading bacteria were studied. The results indicated that seven strains of fufenozide degradeing bacteria, named as DDH01, DDH03, DDH04, DDH04, DDH05, DDH07 and DDH07 respectively, were isolated from soil contaminated with fufenozide. DDH01, DDH02, DDH04 and DDH05 of seven fufenozide degrading bacteria, was gram-positive bacteria, and DDH03, DDH06 and DDH07 was gram-negative bacteria. All of seven strains of fufenozide degrading bacteria were not spores, weeks flagella, rod-shaped bacteria. DDH06 and DDH07 had capsules, and the remaining five strains had not capsule. The colonies formed by seven strains of fufenozide degradation bacteria on beef extract peptone medium plate were milky white colonies with irregular edges, thinner lawn, smaller colony with smooth surface. The growth of 7 strains of fufenozide degradation bacteria was significantly affected by the concentration of fufenozide, All of 7 strains grown in the range from 0.00025 g/mL to 1 g/mL of 10% fufenozide suspension. DDH2 was the best among the 7 strains of fufenozide degrading bacteria grown in 10% fufenozide suspension medium.
Vacheva, Anna; Ivanova, Radka; Paunova-Krasteva, Tsvetelina; Stoitsova, Stoyanka
2012-06-01
It has recently been shown that pathogens with a limited capacity for sessile growth (like some Escherichia coli O157 strains) can benefit from the presence of other bacteria and form mixed biofilms with companion strains. This study addresses the question whether pathogens may influence attached growth of E. coli non-pathogenic strains via secreted factors. We compared the biofilm-modulating effects of sterile stationary-phase culture media of a biofilm non-producing strain of E. coli O157:H, a laboratory biofilm-producing E. coli K-12 strain and a biofilm-forming strain of the pathogen Yersina enterocolitica O:3. Sessile growth was monitored as biomass (crystal violet assay), exopolysaccharide (ELLA) and morphology (scanning electron and confocal laser microscopy). With two of the E. coli K-12 strains stimulation of biofilm formation by all supernatants was achieved, but only the pathogens' secreted products induced biomass increase in some 'biofilm-deficient' K-12 strains. Lectin-peroxidase labeling indicated changes in colanic acid and poly-N-acetylglucosamine amounts in extracellular matrices. The contribution of indole, protein and polysaccharide to the biofilm-modulating activities of the supernatants was compared. Indole, in concentrations equal to those established in the supernatants, suppressed sessile growth in one K-12 strain. Proteinase K significantly reduced the stimulatory effects of all supernatants, indicating a prominent role of protein/peptide factor(s) in biofilm promotion. The amount of released polysaccharides (rPS) in the supernatants was quantitated then comparable quantities of isolated rPS were applied during biofilm growth. The three rPS had notable strain-specific effects with regard to both the strain-source of the rPS and the E. coli K-12 target strain.
Proteolytic and antimicrobial activity of lactic acid bacteria grown in goat milk.
Atanasova, Jivka; Moncheva, Penka; Ivanova, Iskra
2014-11-02
We examined 62 strains and 21 trade starter cultures from the collection of LB Bulgaricum PLC for proteolytic and antimicrobial activity of lactic acid bacteria (LAB) grown in goat milk. The aim of this study was to investigate the fermentation of caseins, α-lactalbumin and β-lactoglobulin by LAB, using the o -phthaldialdehyde (OPA) spectrophotometric assay and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The proteolysis targeted mainly caseins, especially β-casein. Whey proteins were proteolyzed, essentially β-lactoglobulin. The proteolytic activity of Lactococcus lactis l598, Streptococcus thermophilus t3D1, Dt1, Lactobacillus lactis 1043 and L. delbrueckii subsp. bulgaricus b38, b122 and b24 was notably high. The proteolysis process gave rise to medium-sized peptide populations. Most of the examined strains showed antimicrobial activity against some food pathogens, such as Escherichia coli , Staphylococcus aureus , Salmonella cholere enteridis , Listeria monocytogenes , Listeria innocua and Enterobacter aerogenes . The most active producers of antimicrobial-active peptides were strains of L. delbrueckii subsp. bulgaricus and S. thermophilus , which are of practical importance. The starter cultures containing the examined species showed high proteolytic and antimicrobial activity in skimmed goat milk. The greatest antimicrobial activity of the cultures was detected against E. aerogenes . The obtained results demonstrated the significant proteolytic potential of the examined strains in goat milk and their potential for application in the production of dairy products from goat's milk. The present results could be considered as the first data on the proteolytic capacity of strains and starter cultures in goat milk for the purposes of trade interest of LB Bulgaricum PLC.
Ratajczak, Céline; Duez, Catherine; Grangette, Corinne; Pochard, Pierre; Tonnel, André-Bernard; Pestel, Joël
2007-01-01
Lactic acid bacteria (LAB) are Gram positive nonpathogenic commensal organisms present in human gastrointestinal tract. In vivo, LAB are separated from antigen-presenting cells such as dendritic cells (DC) by the intestinal epithelial barrier. In this study, the impact of one LAB strain (Lactobacillus casei ATCC393) on human monocyte-derived DC from allergic and healthy donors was assessed by using a polarized epithelium model. Confocal and flow cytometer analyses showed that immature DC efficiently captured FITC-labelled L. casei through the epithelial layer. After interaction with L. casei, DC acquired a partial maturation status (i.e., CD86 and CD54 increase) and increased their interleukin (IL)-10 and IL-12 production. Interestingly, after activation by L. casei in the presence of experimental epithelium, DC from allergic patients instructed autologous naïve CD4+ T cells to produce more interferon-γ than without the epithelium. Thus by modulating human DC reactivity, LAB and intestinal epithelium might modify T cell immune response and regulate the development of allergic reaction. PMID:17497025
Ratajczak, Céline; Duez, Catherine; Grangette, Corinne; Pochard, Pierre; Tonnel, André-Bernard; Pestel, Joël
2007-01-01
Lactic acid bacteria (LAB) are Gram positive nonpathogenic commensal organisms present in human gastrointestinal tract. In vivo, LAB are separated from antigen-presenting cells such as dendritic cells (DC) by the intestinal epithelial barrier. In this study, the impact of one LAB strain (Lactobacillus casei ATCC393) on human monocyte-derived DC from allergic and healthy donors was assessed by using a polarized epithelium model. Confocal and flow cytometer analyses showed that immature DC efficiently captured FITC-labelled L. casei through the epithelial layer. After interaction with L. casei, DC acquired a partial maturation status (i.e., CD86 and CD54 increase) and increased their interleukin (IL)-10 and IL-12 production. Interestingly, after activation by L. casei in the presence of experimental epithelium, DC from allergic patients instructed autologous naïve CD4(+) T cells to produce more interferon-gamma than without the epithelium. Thus by modulating human DC reactivity, LAB and intestinal epithelium might modify T cell immune response and regulate the development of allergic reaction.
Ait Ouali, Fatma; Al Kassaa, Imad; Cudennec, Benoit; Abdallah, Marwan; Bendali, Farida; Sadoun, Djamila; Chihib, Nour-Eddine; Drider, Djamel
2014-11-17
Two hundred and thirty individual clones of microorganisms were recovered from milk tanks and milking machine surfaces at two distinct farms (Bejaja City, Algeria). Of these clones, 130 were identified as lactic acid bacteria (LAB). In addition Escherichia coli, Salmonella, Staphylococcus aureus and Pseudomonas aeruginosa species were identified in the remaining 100 isolates-spoilage isolate. These isolates were assayed for ability to form biofilms. S. aureus, Lactobacillus brevis strains LB1F2, LB14F1 and LB15F1, and Lactobacillus pentosus strains LB2F2 and LB3F2 were identified as the best biofilm formers. Besides, these LAB isolates were able to produce proteinaceous substances with antagonism against the aforementioned spoilage isolates, when grown in MRS or TSB-YE media. During the screening, L. pentosus LB3F2 exhibited the highest antibacterial activity when grown in TSB-YE medium at 30 °C. Additionally, L. pentosus LB3F2 was able to strongly hamper the adhesion of S. aureus SA3 on abiotic surfaces as polystyrene and stainless steel slides. LAB isolates did not show any hemolytic activity and all of them were sensitive to different families of antibiotic tested. It should be pointed out that LB3F2 isolate was not cytotoxic on the intestinal cells but could stimulate their metabolic activity. This report unveiled the potential of LB1F2, LB14F1, LB15F1, LB2F2, and LB3F2 isolates to be used as natural barrier or competitive exclusion organism in the food processing sector as well as a positive biofilm forming bacteria. Copyright © 2014 Elsevier B.V. All rights reserved.
Pandey, Sony; Sree, Ayinampudi; Sethi, Dipti Priya; Kumar, Chityal Ganesh; Kakollu, Sudha; Chowdhury, Lipsa; Dash, Soumya Suchismita
2014-02-15
Acetylcholinesterase (AChE) inhibitors or anticholinesterases reduce the activity of enzyme acetylcholinesterase that degrades the neurotransmitter acetylcholine in the brain. The inhibitors have a significant pharmacological role in neurodegenerative diseases like Alzheimer's and Parkinson's etc. Although plants have been a significant source of these compounds, there are very few sporadic reports of microorganisms producing such inhibitors. Anticholinesterase activity in bacterial associates of marine soft corals and sponges were not previously reported. We screened 887 marine bacteria for the presence of acetylcholinesterase inhibitors, in a microplate based assay, and found that 140 (15.8%) of them inhibit the electric eel enzyme, acetylcholinesterase. Majority of the active isolates were bacterial associates of soft corals followed by sediment isolates while most of the potent inhibitors belonged to the bacterial associates of marine sponges. Maximum inhibition (54%) was exhibited by a bacterial strain M18SP4P (ii), isolated from the marine sponge Fasciospongia cavernosa. Based on phenotypic characterization and 16S rDNA sequencing, the strain was identified as Bacillus subtilis - revealing yet another activity in a strain of the model organism that is considered to be a cell factory. TLC bioautography of the methanol extract of this culture, showed the presence of two major components having this activity, when compared to Galanthamine, the positive control. From the results of our study, we conclude that acetylcholinesterase inhibitors are quite prevalent in marine bacteria, particularly the bacterial associates of marine invertebrates. Several potential AChE inhibitors in marine bacteria are waiting to be discovered to provide easily manipulable natural sources for the mass production of these therapeutic compounds.
Screening and characterization of novel bacteriocins from lactic acid bacteria.
Zendo, Takeshi
2013-01-01
Bacteriocins produced by lactic acid bacteria (LAB) are expected to be safe antimicrobial agents. While the best studied LAB bacteriocin, nisin A, is widely utilized as a food preservative, various novel ones are required to control undesirable bacteria more effectively. To discover novel bacteriocins at the early step of the screening process, we developed a rapid screening system that evaluates bacteriocins produced by newly isolated LAB based on their antibacterial spectra and molecular masses. By means of this system, various novel bacteriocins were identified, including a nisin variant, nisin Q, a two-peptide bacteriocin, lactococcin Q, a leaderless bacteriocin, lacticin Q, and a circular bacteriocin, lactocyclicin Q. Moreover, some LAB isolates were found to produce multiple bacteriocins. They were characterized as to their structures, mechanisms of action, and biosynthetic mechanisms. Novel LAB bacteriocins and their biosynthetic mechanisms are expected for applications such as food preservation and peptide engineering.
Lavilla Lerma, Leyre; Benomar, Nabil; Gálvez, Antonio; Abriouel, Hikmate
2013-02-01
In order to investigate the prevalence of resistant bacteria to biocides and/or antibiotics throughout meat chain production from sacrifice till end of production line, samples from various surfaces of a goat and lamb slaughterhouse representative of the region were analyzed by the culture dependent approach. Resistant Psychrotrophs (n=255 strains), Pseudomonas sp. (n=166 strains), E. coli (n=23 strains), Staphylococcus sp. (n=17 strains) and LAB (n=82 represented mainly by Lactobacillus sp.) were isolated. Resistant psychrotrophs and pseudomonads (47 and 29%, respectively) to different antimicrobials were frequently detected in almost all areas of meat processing plant regardless the antimicrobial used, although there was a clear shift in the spectrum of other bacterial groups and for this aim such resistance was determined according to several parameters: antimicrobial tested, sampling zone and the bacterial group. Correlation of different parameters was done using a statistical tool "Principal component analysis" (PCA) which determined that quaternary ammonium compounds and hexadecylpyridinium were the most relevant biocides for resistance in Pseudomonas sp., while ciprofloxacin and hexachlorophene were more relevant for psychrotrophs, LAB, and in lesser extent Staphylococcus sp. and Escherichia coli. On the other hand, PCA of sampling zones determined that sacrifice room (SR) and cutting room (CR) considered as main source of antibiotic and/or biocide resistant bacteria showed an opposite behaviour concerning relevance of antimicrobials to determine resistance being hexadecylpyridinium, cetrimide and chlorhexidine the most relevant in CR, while hexachlorophene, oxonia 6P and PHMG the most relevant in SR. In conclusion, rotational use of the relevant biocides as disinfectants in CR and SR is recommended in an environment which is frequently disinfected. Copyright © 2012 Elsevier B.V. All rights reserved.
Macuamule, C L S; Wiid, I J; van Helden, P D; Tanner, M; Witthuhn, R C
2016-01-18
Mycobacterium bovis that causes Bovine tuberculosis (BTB) can be transmitted to humans thought consumption of raw and raw fermented milk products from diseased animals. Lactic acid bacteria (LAB) used in popular traditional milk products in Africa produce anti-microbial compounds that inhibit some pathogenic and spoilage bacteria. M. bovis BCG is an attenuated non-pathogenic vaccine strain of M. bovis and the aim of the study was to determine the effect of the fermentation process on the survival of M. bovis BCG in milk. M. bovis BCG at concentrations of 6 log CFU/ml was added to products of kefir fermentation. The survival of M. bovis BCG was monitored at 12-h intervals for 72 h by enumerating viable cells on Middlebrook 7H10 agar plates enriched with 2% BD BACTEC PANTA™. M. bovis BCG was increasingly reduced in sterile kefir that was fermented for a period of 24h and longer. In the milk fermented with kefir grains, Lactobacillus paracasei subsp. paracasei or Lactobacillus casei, the viability of M. bovis BCG was reduced by 0.4 logs after 24h and by 2 logs after 48 h of fermentation. No viable M. bovis BCG was detected after 60 h of fermentation. Results from this study show that long term fermentation under certain conditions may have the potential to inactivate M. bovis BCG present in the milk. However, to ensure safety of fermented milk in Africa, fermentation should be combined with other hurdle technologies such as boiling and milk pasteurisation. Copyright © 2015 Elsevier B.V. All rights reserved.
Nguyen, Doan Thi Lam; Van Hoorde, Koenraad; Cnockaert, Margo; De Brandt, Evie; Aerts, Maarten; Binh Thanh, Le; Vandamme, Peter
2013-04-15
An important part of the daily nourishment in Vietnam constitutes of fermented vegetables. Bacteria and especially lactic acid bacteria play a central role in the production of many fermented vegetables. The current study was conducted to investigate the diversity of native lactic acid bacteria (LAB) populations in 'dua muoi' (mustard and beet fermentation) and 'ca muoi' (eggplant fermentation), three types of popular traditional fermented vegetables of Vietnamese origin. To this end a polyphasic approach combining matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and pheS gene sequence analysis was used. In addition, denaturing gradient gel electrophoresis was performed as a culture-independent method to complement the observed culturable diversity data. A total of 881 LAB isolates were recovered from 21 different samples. Predominant LAB associated with 'dua muoi' and 'ca muoi' were identified as Lactobacillus fermentum (56.6%), Lactobacillus pentosus (24.4%) and Lactobacillus plantarum (17.1%). Less abundant species were Pediococcus pentosaceus (1.0%) and Lactobacillus brevis (0.5%). Species present less than 0.1% included Lactobacillus paracasei, Lactobacillus pantheris and Pediococcus acidilactici. In contrast to fermented mustard and beet with the highest prevalence of L. fermentum, the species most recovered from fermented eggplant samples was L. pentosus. In addition, an important degree of genetic variability within the different predominant species was observed and strain dependency correlating with the type of fermented vegetable or location of production could be demonstrated using multivariate statistics. This research gives an extensive and detailed inventory of the LAB diversity associated with the production of diverse Vietnamese fermented vegetables and demonstrates the influence of type of raw material and/or production location and conditions on this diversity. Copyright © 2013 Elsevier B.V. All rights
Feng, Fayun; Ge, Jing; Li, Yisong; He, Shuang; Zhong, Jianfeng; Liu, Xianjing; Yu, Xiangyang
2017-10-01
Endophytic bacteria reside in plant tissues, such as roots, stems, leaves and seeds. Most of them can stimulate plant growth or alleviate phytotoxicity of pollutants. There are handful species with dual functions stimulating plant growth and degrading pollutants have been reported. Five endophytic bacteria were isolated from chlorpyrifos (CP) treated rice plants and identified as Pseudomonas aeruginosa strain RRA, Bacillus megaterium strain RRB, Sphingobacterium siyangensis strain RSA, Stenotrophomonas pavanii strain RSB and Curtobacterium plantarum strain RSC according to morphological characteristics, physiological and biochemical tests, and 16S rDNA phylogeny. All of them possessed some plant growth promotional traits, including indole acetic acid and siderophore production, secretion of phosphate solubilization and 1-aminocyclopropane-1-carboxylate deaminase. The bacteria were marked with the green fluorescent protein (gfp) gene and successfully colonized into rice plants. All isolates were able to degrade CP in vitro and in vivo. The five isolates degraded more than 90% of CP in 24 h when the initial concentration was lower than 5 mg/L. CP degradation was significantly enhanced in the infested rice plants and rice grains. The final CP residual was reduced up to 80% in the infested rice grains compared to the controls. The results indicate that these isolates are promising bio-inoculants for the removal or detoxification of CP residues in rice plants and grains. Copyright © 2017 Elsevier Ltd. All rights reserved.
The Effect of LAB Silage Inoculants on the Rumen Environment--Current Research Status
USDA-ARS?s Scientific Manuscript database
Inoculants containing mainly lactic acid bacteria (LAB) are the most common additives used in making silage. Their function is to promote intensive production of lactic acid and rapid decrease in pH and so minimize fermentation losses. Some LAB inoculants reduce aerobic spoilage. In addition, feedin...
Nakamura, Toshihide; Sekiyama, Yasuyo; Kikuchi, Jun
2017-01-01
In this study, we investigated the applicability of NMR-based metabolomics to discriminate strain-dependent fermentation characteristics of lactic acid bacteria (LAB), which are important microorganisms for fermented food production. To evaluate the discrimination capability, six type strains of Lactobacillus species and six additional L. brevis strains were used focusing on i) the difference between homo- and hetero-lactic fermentative species and ii) strain-dependent characteristics within L. brevis. Based on the differences in the metabolite profiles of fermented vegetable juices, non-targeted principal component analysis (PCA) clearly separated the samples into those inoculated with homo- and hetero-lactic fermentative species. The separation was primarily explained by the different levels of dominant metabolites (lactic acid, acetic acid, ethanol, and mannitol). Orthogonal partial least squares discrimination analysis, based on a regions-of-interest (ROIs) approach, revealed the contribution of low-abundance metabolites: acetoin, phenyllactic acid, p-hydroxyphenyllactic acid, glycerophosphocholine, and succinic acid for homolactic fermentation; and ornithine, tyramine, and γ-aminobutyric acid (GABA) for heterolactic fermentation. Furthermore, ROIs-based PCA of seven L. brevis strains separated their strain-dependent fermentation characteristics primarily based on their ability to utilize sucrose and citric acid, and convert glutamic acid and tyrosine into GABA and tyramine, respectively. In conclusion, NMR metabolomics successfully discriminated the fermentation characteristics of the tested strains and provided further information on metabolites responsible for these characteristics, which may impact the taste, aroma, and functional properties of fermented foods. PMID:28759594
Qin, Chao; Wang, Cheng-Hua; Wang, Ying-Ying; Sun, Shi-Qing; Wang, Huan-Huan; Xue, Chao-Bin
2018-04-02
Diamondback moth, Plutella xylostella (L.; Lepidoptera: Plutellidae), is an important pest of crucifers worldwide. The extensive use of diamide insecticides has led to P. xylostella resistance and this presents a serious threat to vegetable production. We selected chlorantraniliprole (Rf) and flubendiamide (Rh) resistance strains of P. xylostella with resistance ratios of 684.54-fold and 677.25-fold, respectively. The Rf and Rh strains underwent 46 and 36 generations of lab-selection for resistance, respectively. Low cross resistance of Rh to cyantraniliprole was found. Cross resistance to chlorfenapyr, tebufenozid, and indoxacarb was not found in Rf and Rh strains. The P. xylostella ryanodine receptor gene (PxRyR) transcripts level in the Rf and Rh strains was up-regulated. Except for Rf34 and Rh36, PxRyR expression in all generations of Rf and Rh selection gradually increased with increasing resistance. Two resistant populations were field-collected from Guangzhou Baiyun (Rb) and Zengcheng (Rz) and propagated for several generations without exposure to any pesticide had higher PxRyR expression than the susceptible strain (S). In the S strain, PxRyR expression was not related to the resistance ratio. Gene sequencing found that the RyR 4946 gene site was glycine (G) in the S, Rf, and Rh strains, and was glutamate (E) with 70% and 80% frequency in the Rb and Rz populations, respectively. The 4946 gene site was substituted by valine (V) with the frequency of 30% and 20% in Rb and Rz populations, respectively. These results increase the understanding of the mechanisms of diamide insecticide resistance in P. xylostella.
Interactions between Cooccurring Lactic Acid Bacteria in Honey Bee Hives.
Rokop, Z P; Horton, M A; Newton, I L G
2015-10-01
In contrast to the honey bee gut, which is colonized by a few characteristic bacterial clades, the hive of the honey bee is home to a diverse array of microbes, including many lactic acid bacteria (LAB). In this study, we used culture, combined with sequencing, to sample the LAB communities found across hive environments. Specifically, we sought to use network analysis to identify microbial hubs sharing nearly identical operational taxonomic units, evidence which may indicate cooccurrence of bacteria between environments. In the process, we identified interactions between noncore bacterial members (Fructobacillus and Lactobacillaceae) and honey bee-specific "core" members. Both Fructobacillus and Lactobacillaceae colonize brood cells, bee bread, and nectar and may serve the role of pioneering species, establishing an environment conducive to the inoculation by honey bee core bacteria. Coculture assays showed that these noncore bacterial members promote the growth of honey bee-specific bacterial species. Specifically, Fructobacillus by-products in spent medium supported the growth of the Firm-5 honey bee-specific clade in vitro. Metabolic characterization of Fructobacillus using carbohydrate utilization assays revealed that this strain is capable of utilizing the simple sugars fructose and glucose, as well as the complex plant carbohydrate lignin. We tested Fructobacillus for antibiotic sensitivity and found that this bacterium, which may be important for establishment of the microbiome, is sensitive to the commonly used antibiotic tetracycline. Our results point to the possible significance of "noncore" and environmental microbial community members in the modulation of honey bee microbiome dynamics and suggest that tetracycline use by beekeepers should be limited. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
Eijsink, Vincent G H; Axelsson, Lars; Diep, Dzung B; Håvarstein, Leiv S; Holo, Helge; Nes, Ingolf F
2002-08-01
Lactic acid bacteria (LAB) fight competing Gram-positive microorganisms by secreting anti-microbial peptides called bacteriocins. Peptide bacteriocins are usually divided into lantibiotics (class I) and non-lantibiotics (class II), the latter being the main topic of this review. During the past decade many of these bacteriocins have been isolated and characterized, and elements of the genetic mechanisms behind bacteriocin production have been unravelled. Bacteriocins often have a narrow inhibitory spectrum, and are normally most active towards closely related bacteria likely to occur in the same ecological niche. Lactic acid bacteria seem to compensate for these narrow inhibitory spectra by producing several bacteriocins belonging to different classes and having different inhibitory spectra. The latter may also help in counteracting the possible development of resistance mechanisms in target organisms. In many strains, bacteriocin production is controlled in a cell-density dependent manner, using a secreted peptide-pheromone for quorum-sensing. The sensing of its own growth, which is likely to be comparable to that of related species, enables the producing organism to switch on bacteriocin production at times when competition for nutrients is likely to become more severe. Although today a lot is known about LAB bacteriocins and the regulation of their production, several fundamental questions remain to be solved. These include questions regarding mechanisms of immunity and resistance, as well as the molecular basis of target-cell specificity.
Antimicrobial peptides against contaminating bacteria in fuel ethanol production
USDA-ARS?s Scientific Manuscript database
Lactic acid bacteria (LAB) are commonly found as contaminants of fuel ethanol production, resulting in reduced ethanol yields: (1). Recent reports suggest that LAB can develop resistance to antibiotics such as virginiamycin and penicillin that are commonly used to control bacterial contamination; (2...
Antimicrobial peptides against contaminating bacteria in fuel ethanol production
USDA-ARS?s Scientific Manuscript database
Lactic acid bacteria (LAB) are commonly found as contaminants of fuel ethanol production, resulting in reduced ethanol yields (1). Recent reports suggest that LAB can develop resistance to antibiotics such as virginiamycin and penicillin that are commonly used to control bacterial contamination (2)...
Zbrun, María V.; Soto, Lorena P.; Bertozzi, Ezequiel; Sequeira, Gabriel J.; Marti, Luis E.; Signorini, Marcelo L.; Armesto, Roberto Rodríguez; Rosmini, Marcelo R.
2012-01-01
The purpose of this study was to evaluate the capacity of a lactic acid bacteria (LAB) inoculum to protect calves with or without lactose supplements against Salmonella Dublin infection by evaluating histopathological lesions and pathogen translocation. Fifteen calves were divided into three groups [control group (C-G), a group inoculated with LAB (LAB-G), and a group inoculated with LAB and given lactose supplements (L-LAB-G)] with five, six, and four animals, respectively. The inoculum, composed of Lactobacillus (L.) casei DSPV 318T, L. salivarius DSPV 315T, and Pediococcus acidilactici DSPV 006T, was administered with milk replacer. The LAB-G and L-LAB-G received a daily dose of 109 CFU/kg body weight of each strain throughout the experiment. Lactose was provided to the L-LAB-G in doses of 100 g/day. Salmonella Dublin (2 × 1010 CFU) was orally administered to all animals on day 11 of the experiment. The microscopic lesion index values in target organs were 83%, 70%, and 64.3% (p < 0.05) for the C-G, LAB-G, and L-LAB-G, respectively. Administration of the probiotic inoculum was not fully effective against infection caused by Salmonella. Although probiotic treatment was unable to delay the arrival of pathogen to target organs, it was evident that the inoculum altered the response of animals against pathogen infection. PMID:23000583
Biosorption of heavy metals by lactic acid bacteria and identification of mercury binding protein.
Kinoshita, Hideki; Sohma, Yui; Ohtake, Fumika; Ishida, Mitsuharu; Kawai, Yasushi; Kitazawa, Haruki; Saito, Tadao; Kimura, Kazuhiko
2013-09-01
Heavy metals cause various health hazards. Using lactic acid bacteria (LAB), we tested the biosorption of heavy metals e.g. cadmium (Cd) (II), lead (Pb) (II), arsenic (As) (III), and mercury (Hg) (II). Cd (II) sorption was tested in 103 strains using atomic absorption spectrophotometery (AAS). Weissella viridescens MYU 205 (1 × 10(8) cells/ml) decreased Cd (II) levels in citrate buffer (pH 6.0) from one ppm to 0.459 ± 0.016 ppm, corresponding to 10.46 μg of Cd (II). After screening, 11 LAB strains were tested using various pH (pH 4.0, 5.0, 6.0, 7.0) showing the sorption was acid sensitive; and was cell concentration dependent, where the Cd (II) concentration decreased from one ppm to 0.042 (max)/0.255 (min) ppm at 1 × 10(10) cells/ml. Additionally, the biosorption of Pb (II), As (III), and Hg (II) were tested using an inductively coupled plasma mass spectrometer (ICP-MS). The Hg (II) concentration was reduced the most followed by Pb (II) and As (III). Many of the bacterial cell surface proteins of W. viridescens MYU 205 showed binding to Hg (II) using the Hg (II) column assay. Having a CXXC motif, a ∼14 kDa protein may be one of the Hg (II) binding proteins. LAB biosorption may aid the detoxification of people exposed to heavy metals. Copyright © 2013 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.
NASA Astrophysics Data System (ADS)
Nur Jannah, Siti; Rini Saraswati, Tyas; Handayani, Dwi; Pujiyanto, Sri
2018-05-01
Food borne disease results from ingestion of water and wide variety of food contaminated with pathogenic organisms. The main causes of food borne diseases are bacteria, such as Escherichia coli and Staphylococcus aureus. The objective of this study was to determine antimicrobial activity of lactic acid bacteria (LAB) isolated from local chicken gastrointestinal tract with an emphasis on their probiotic properties. The colonies of bacteria that producing clear zone on MRSA plus 0.5% CaCO3, Gram-positive and catalase-negative were isolated as lactic acid bacteria. Some of the strains (10 isolates) were tested for their ability to inhibit growth of Escherichia coli and Staphylococcus aureus, and for acid pH and bile salt tolerance. The results showed that the all selected isolates producing antimicrobial compounds inhibits the growth of Escherichia coli and Staphylococcus aureus, both in the supernatant and supernatant plus 2M NaOH, and still growing in medium condition with pH 2.0 and 0.1% bile salt. It revealing the potential use of the lactic acid bacteria from chicken gastrointestinal tract for probiotics in food.
Wieme, Anneleen D; Spitaels, Freek; Aerts, Maarten; De Bruyne, Katrien; Van Landschoot, Anita; Vandamme, Peter
2014-08-18
Applicability of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identification of beer-spoilage bacteria was examined. To achieve this, an extensive identification database was constructed comprising more than 4200 mass spectra, including biological and technical replicates derived from 273 acetic acid bacteria (AAB) and lactic acid bacteria (LAB), covering a total of 52 species, grown on at least three growth media. Sequence analysis of protein coding genes was used to verify aberrant MALDI-TOF MS identification results and confirmed the earlier misidentification of 34 AAB and LAB strains. In total, 348 isolates were collected from culture media inoculated with 14 spoiled beer and brewery samples. Peak-based numerical analysis of MALDI-TOF MS spectra allowed a straightforward species identification of 327 (94.0%) isolates. The remaining isolates clustered separately and were assigned through sequence analysis of protein coding genes either to species not known as beer-spoilage bacteria, and thus not present in the database, or to novel AAB species. An alternative, classifier-based approach for the identification of spoilage bacteria was evaluated by combining the identification results obtained through peak-based cluster analysis and sequence analysis of protein coding genes as a standard. In total, 263 out of 348 isolates (75.6%) were correctly identified at species level and 24 isolates (6.9%) were misidentified. In addition, the identification results of 50 isolates (14.4%) were considered unreliable, and 11 isolates (3.2%) could not be identified. The present study demonstrated that MALDI-TOF MS is well-suited for the rapid, high-throughput and accurate identification of bacteria isolated from spoiled beer and brewery samples, which makes the technique appropriate for routine microbial quality control in the brewing industry. Copyright © 2014 Elsevier B.V. All rights reserved.
Rastegar, Ayoob; Nazari, Shahram; Allahabadi, Ahmad; Falanji, Farahnaz; Akbari Dourbash, Fakhreddin Akbari Dourbash; Rezai, Zahra; Alizadeh Matboo, Soudabeh; Hekmat-Shoar, Reza; Mohseni, Seyed Mohsen; Majidi, Gharib
2017-01-01
Background: Nanoscale poly (amidoamine) dendrimers have been investigated for their biological demands, but their antibacterial activity has not been widely discovered. Thus, the sixth generation of poly (amidoamine) dendrimer (PAMAM-G6) was synthesized and its antibacterial activities were evaluated on Gram-negative bacteria; P. aeruginosa, E. coli, A. baumannii, S. typhimurium, S. dysenteriae, K. pneumoniae, P. mirabilis , and Gram-positive bacteria, and S.aureus and B. subtilis , which were isolated from different clinical specimens and standard strains of these bacteria. Methods: In this study, 980 specimens including urine (47%), blood (27%), sputum (13%), wounds (8%), and burns (5%) were collected from clinical specimens of 16 hospitals and clinics in city of Sabzevar, Iran. Then, the target bacteria were isolated and identified using standard methods. Minimum inhibitory concentration and minimum bactericidal concentrations against Gram-positive and Gram-negative bacteria were determined according to guidelines described by clinical and laboratory standards institute (CLSI). Standard discs were prepared using 0.025, 0.25, 2.5, and 25 μg/mL concentrations of PAMAM-G6 on Mueller-Hinton agar plates to determinate the zone of inhibition. The cytotoxicity of PAMAM-G6 dendrimer was evaluated in HCT116 cells by MTT assay. Results: The most important isolated bacteria were E. coli (23.65%), S. aureus (24.7%), P. aeruginosa (10.49%), B. subtilis (7.7%), S. typhimurium (8.87%), A. baumannii (7.02%), K. pneumoniae (7.1%), P. mirabilis (6.46%), and S. dysenteriae (3.6%). Moreover, it was found that poly (amidoamine)-G6 exhibited more antibacterial efficacy on standard strains than isolated bacteria from clinical samples (p<0.05). The cytotoxicity of PAMAM-G6 to the cells showed that cytotoxicity depended on the concentration level and exposure time. Conclusion: The PAMAM-G6 dendrimer showed a positive impact on the removal of dominant bacterial isolated from clinical
Rastegar, Ayoob; Nazari, Shahram; Allahabadi, Ahmad; Falanji, Farahnaz; Akbari Dourbash, Fakhreddin Akbari Dourbash; Rezai, Zahra; Alizadeh Matboo, Soudabeh; Hekmat-Shoar, Reza; Mohseni, Seyed Mohsen; Majidi, Gharib
2017-01-01
Background: Nanoscale poly (amidoamine) dendrimers have been investigated for their biological demands, but their antibacterial activity has not been widely discovered. Thus, the sixth generation of poly (amidoamine) dendrimer (PAMAM-G6) was synthesized and its antibacterial activities were evaluated on Gram-negative bacteria; P. aeruginosa, E. coli, A. baumannii, S. typhimurium, S. dysenteriae, K. pneumoniae, P. mirabilis, and Gram-positive bacteria, and S.aureus and B. subtilis, which were isolated from different clinical specimens and standard strains of these bacteria. Methods: In this study, 980 specimens including urine (47%), blood (27%), sputum (13%), wounds (8%), and burns (5%) were collected from clinical specimens of 16 hospitals and clinics in city of Sabzevar, Iran. Then, the target bacteria were isolated and identified using standard methods. Minimum inhibitory concentration and minimum bactericidal concentrations against Gram-positive and Gram-negative bacteria were determined according to guidelines described by clinical and laboratory standards institute (CLSI). Standard discs were prepared using 0.025, 0.25, 2.5, and 25 μg/mL concentrations of PAMAM-G6 on Mueller-Hinton agar plates to determinate the zone of inhibition. The cytotoxicity of PAMAM-G6 dendrimer was evaluated in HCT116 cells by MTT assay. Results: The most important isolated bacteria were E. coli (23.65%), S. aureus (24.7%), P. aeruginosa (10.49%), B. subtilis (7.7%), S. typhimurium (8.87%), A. baumannii (7.02%), K. pneumoniae (7.1%), P. mirabilis (6.46%), and S. dysenteriae (3.6%). Moreover, it was found that poly (amidoamine)–G6 exhibited more antibacterial efficacy on standard strains than isolated bacteria from clinical samples (p<0.05). The cytotoxicity of PAMAM-G6 to the cells showed that cytotoxicity depended on the concentration level and exposure time. Conclusion: The PAMAM-G6 dendrimer showed a positive impact on the removal of dominant bacterial isolated from clinical
Manufacture of Probiotic Bacteria
NASA Astrophysics Data System (ADS)
Muller, J. A.; Ross, R. P.; Fitzgerald, G. F.; Stanton, C.
Lactic acid bacteria (LAB) have been used for many years as natural biopreservatives in fermented foods. A small group of LAB are also believed to have beneficial health effects on the host, so called probiotic bacteria. Probiotics have emerged from the niche industry from Asia into European and American markets. Functional foods are one of the fastest growing markets today, with estimated growth to 20 billion dollars worldwide by 2010 (GIA, 2008). The increasing demand for probiotics and the new food markets where probiotics are introduced, challenges the industry to produce high quantities of probiotic cultures in a viable and stable form. Dried concentrated probiotic cultures are the most convenient form for incorporation into functional foods, given the ease of storage, handling and transport, especially for shelf-stable functional products. This chapter will discuss various aspects of the challenges associated with the manufacturing of probiotic cultures.
De Santis, Riccardo; Ancora, Massimo; De Massis, Fabrizio; Ciammaruconi, Andrea; Zilli, Katiuscia; Di Giannatale, Elisabetta; Pittiglio, Valentina; Fillo, Silvia; Lista, Florigio
2013-10-01
Brucellosis, one of the most important re-emerging zoonoses in many countries, is caused by bacteria belonging to the genus Brucella. Furthermore these bacteria represent potential biological warfare agents and the identification of species and biovars of field strains may be crucial for tracing back source of infection, allowing to discriminate naturally occurring outbreaks instead of bioterrorist events. In the last years, multiple-locus variable-number tandem repeat analysis (MLVA) has been proposed as complement of the classical biotyping methods and it has been applied for genotyping large collections of Brucella spp. At present, the MLVA band profiles may be resolved by automated or manual procedures. The Lab on a chip technology represents a valid alternative to standard genotyping techniques (as agarose gel electrophoresis) and it has been previously used for Brucella genotyping. Recently, a new high-throughput genotyping analysis system based on capillary gel electrophoresis, the QIAxcel, has been described. The aim of the study was to evaluate the ability of two DNA sizing equipments, the QIAxcel System and the Lab chip GX, to correctly call alleles at the sixteen loci including one frequently used MLVA assay for Brucella genotyping. The results confirmed that these technologies represent a meaningful advancement in high-throughput Brucella genotyping. Considering the accuracy required to confidently resolve loci discrimination, QIAxcel shows a better ability to measure VNTR allele sizes compared to LabChip GX.
BELHADJ, Hani; HARZALLAH, Daoud; BOUAMRA, Dalila; KHENNOUF, Seddik; Dahamna, Saliha; GHADBANE, Mouloud
2014-01-01
In the present work, five hundred and sixty-seven isolates of lactic acid bacteria were recovered from raw bee pollen grains. All isolates were screened for their antagonistic activity against both Gram-positive and Gram-negative pathogenic bacteria. Neutralized supernatants of 54 lactic acid bacteria (LAB) cultures from 216 active isolates inhibited the growth of indicator bacteria. They were phenotypically characterized, based on the fermentation of 39 carbohydrates. Using the simple matching coefficient and unweighted pair group algorithm with arithmetic averages (UPGMA), seven clusters with other two members were defined at the 79% similarity level. The following species were characterized: Lactobacillus plantarum, Lactobacillus fermentum, Lactococcus lactis, Pediococcus acidilactici, Pediococcus pentosaceus, and unidentified lactobacilli. Phenotypic characteristics of major and minor clusters were also identified. Partial sequencing of the 16S rRNA gene of representative isolates from each cluster was performed, and ten strains were assigned to seven species: Lactobacillus plantarum, Lactobacillus fermentum, Lactococcus lactis, Lactobacillus ingluviei, Pediococcus pentosaceus, Lactobacillus acidipiscis and Weissella cibaria. The molecular method used failed to determine the exact taxonomic status of BH0900 and AH3133. PMID:24936378
Belhadj, Hani; Harzallah, Daoud; Bouamra, Dalila; Khennouf, Seddik; Dahamna, Saliha; Ghadbane, Mouloud
2014-01-01
In the present work, five hundred and sixty-seven isolates of lactic acid bacteria were recovered from raw bee pollen grains. All isolates were screened for their antagonistic activity against both Gram-positive and Gram-negative pathogenic bacteria. Neutralized supernatants of 54 lactic acid bacteria (LAB) cultures from 216 active isolates inhibited the growth of indicator bacteria. They were phenotypically characterized, based on the fermentation of 39 carbohydrates. Using the simple matching coefficient and unweighted pair group algorithm with arithmetic averages (UPGMA), seven clusters with other two members were defined at the 79% similarity level. The following species were characterized: Lactobacillus plantarum, Lactobacillus fermentum, Lactococcus lactis, Pediococcus acidilactici, Pediococcus pentosaceus, and unidentified lactobacilli. Phenotypic characteristics of major and minor clusters were also identified. Partial sequencing of the 16S rRNA gene of representative isolates from each cluster was performed, and ten strains were assigned to seven species: Lactobacillus plantarum, Lactobacillus fermentum, Lactococcus lactis, Lactobacillus ingluviei, Pediococcus pentosaceus, Lactobacillus acidipiscis and Weissella cibaria. The molecular method used failed to determine the exact taxonomic status of BH0900 and AH3133.
Ben Braïek, Olfa; Ghomrassi, Hamdi; Cremonesi, Paola; Morandi, Stefano; Fleury, Yannick; Le Chevalier, Patrick; Hani, Khaled; Bel Hadj, Omrane; Ghrairi, Taoufik
2017-06-01
Screening for lactic acid bacteria (LAB) from fresh shrimp samples (Penaeus vannamei) collected from retail seafood markets in the Tunisian's coast, resulted in the isolation of an Enterococcus strain termed Q1. This strain was selected for its antagonistic activity against pathogenic bacteria such as Listeria monocytogenes, Pseudomonas aeruginosa, Lactococcus garvieae and against fungi (Aspergillus niger and Fusarium equiseti). The Q1 strain was characterised using standard morphological and biochemical tests, growth assays at different temperatures, pH and salinity. 16S rRNA, rpoA and pheS gene sequencing, as well as the 16S-23S rRNA intergenic spacer analyses, were combined to identify strain Q1 as a strain of Enterococcus lactis. The bacteriocin produced by E. lactis Q1 is thermostable, active in the pH range from 4.0 to 9.0 and has a bactericidal mode of action. The enterocin P structural gene was detected by specific PCR in strain E. lactis Q1, which is in good agreement with SDS-PAGE data of the purified bacteriocin. A lack of significant antibiotic resistance genes and virulence determinants was confirmed by specific PCRs. This work provides the first description of an enterocin P producer E. lactis strain isolated from a fresh shrimp. Based on its safety properties (absence of haemolytic activity, virulence factors and antibiotic resistance genes), this strain has the potential to be used as a natural additive or adjunct protective culture in food biopreservation and/or probiotic culture.
Carrot Juice Fermentations as Man-Made Microbial Ecosystems Dominated by Lactic Acid Bacteria.
Wuyts, Sander; Van Beeck, Wannes; Oerlemans, Eline F M; Wittouck, Stijn; Claes, Ingmar J J; De Boeck, Ilke; Weckx, Stefan; Lievens, Bart; De Vuyst, Luc; Lebeer, Sarah
2018-06-15
Spontaneous vegetable fermentations, with their rich flavors and postulated health benefits, are regaining popularity. However, their microbiology is still poorly understood, therefore raising concerns about food safety. In addition, such spontaneous fermentations form interesting cases of man-made microbial ecosystems. Here, samples from 38 carrot juice fermentations were collected through a citizen science initiative, in addition to three laboratory fermentations. Culturing showed that Enterobacteriaceae were outcompeted by lactic acid bacteria (LAB) between 3 and 13 days of fermentation. Metabolite-target analysis showed that lactic acid and mannitol were highly produced, as well as the biogenic amine cadaverine. High-throughput 16S rRNA gene sequencing revealed that mainly species of Leuconostoc and Lactobacillus (as identified by 8 and 20 amplicon sequence variants [ASVs], respectively) mediated the fermentations in subsequent order. The analyses at the DNA level still detected a high number of Enterobacteriaceae , but their relative abundance was low when RNA-based sequencing was performed to detect presumptive metabolically active bacterial cells. In addition, this method greatly reduced host read contamination. Phylogenetic placement indicated a high LAB diversity, with ASVs from nine different phylogenetic groups of the Lactobacillus genus complex. However, fermentation experiments with isolates showed that only strains belonging to the most prevalent phylogenetic groups preserved the fermentation dynamics. The carrot juice fermentation thus forms a robust man-made microbial ecosystem suitable for studies on LAB diversity and niche specificity. IMPORTANCE The usage of fermented food products by professional chefs is steadily growing worldwide. Meanwhile, this interest has also increased at the household level. However, many of these artisanal food products remain understudied. Here, an extensive microbial analysis was performed of spontaneous fermented
Tohno, Masanori; Kobayashi, Hisami; Nomura, Masaru; Uegaki, Ryuichi; Cai, Yimin
2012-04-01
In order to understand the relationship between lactic acid bacteria (LAB) species and silage fermentation, a total of 65 LAB strains isolated from mixed pasture of timothy (Phleum pratense L.) and orchardgrass (Dactylis glomerata L.), and its badly preserved silages were subjected to phenotypic and genetic analysis. According to these analyses, the isolates were divided into 13 groups, including Enterococcus gallinarum, Lactobacillus acidipiscis, L. coryniformis subsp. coryniformis, L. coryniformis subsp. torquens, L. curvatus, L. paraplantarum, L. plantarum subsp. argentoratensis, L. plantarum subsp. plantarum, L. sakei subsp. carnosus, Lactococcus garvieae, Lactococcus lactis subsp. cremoris, Leuconostoc pseudomesenteroides, Pediococcus acidilactici, Pediococcus pentosaceus, Weissella hellenica, Weissella paramesenteroides and Carnobacterium divergens. This is the first report to document that C. divergens, L. acidipiscis, L. sakei subsp. carnosus, L. garvieae, phenotypically novel L. lactis subsp. cremoris, E. gallinarum and W. hellenica are present in vegetative forage crops. L. plantarum group strains were most frequently isolated from the badly preserved silages. Some isolates showed a wide range of growth preferences for carbohydrate utilization, optimal growth pH and temperature in vitro, indicating that they have a high growth potential. These results are useful in understanding the diversity of LAB associated with decayed silage of timothy and orchardgrass. © 2011 The Authors. Animal Science Journal © 2011 Japanese Society of Animal Science.
Polyhydroxyalkanoate production potential of heterotrophic bacteria in activated sludge.
Inoue, Daisuke; Suzuki, Yuta; Uchida, Takahiro; Morohoshi, Jota; Sei, Kazunari
2016-01-01
This study was conducted to evaluate the polyhydroxyalkanoate (PHA) production potential of cultivable heterotrophic bacteria in activated sludge by genotypic and phenotypic characterizations. A total of 114 bacterial strains were isolated from four activated sludge samples taken from a lab-scale sequencing batch reactor and three wastewater treatment processes of two municipal wastewater treatment plants. PCR detection of the phaC genes encoding class I and II PHA synthase revealed that 15% of the total isolates possessed phaC genes, all of which had the closest similarities to known phaC genes of α- and β-Proteobacteria and Actinobacteria. PHA production experiments under aerobic and nitrogen-limited conditions showed that 68% of the total isolates were capable of producing PHA from at least one of the six substrates used (acetate, propionate, lactate, butyrate, glucose and glycerol). Genotypic and phenotypic characterizations revealed that 75% of the activated sludge bacteria had PHA production potential. Our results also indicated that short-chain fatty acids would be the preferable substrates for PHA production by activated sludge bacteria, and that there might be a variety of unidentified phaC genes in activated sludge. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.
Acetic acid bacteria: A group of bacteria with versatile biotechnological applications.
Saichana, Natsaran; Matsushita, Kazunobu; Adachi, Osao; Frébort, Ivo; Frebortova, Jitka
2015-11-01
Acetic acid bacteria are gram-negative obligate aerobic bacteria assigned to the family Acetobacteraceae of Alphaproteobacteria. They are members of the genera Acetobacter, Gluconobacter, Gluconacetobacter, Acidomonas, Asaia, Kozakia, Swaminathania, Saccharibacter, Neoasaia, Granulibacter, Tanticharoenia, Ameyamaea, Neokomagataea, and Komagataeibacter. Many strains of Acetobacter and Komagataeibacter have been known to possess high acetic acid fermentation ability as well as the acetic acid and ethanol resistance, which are considered to be useful features for industrial production of acetic acid and vinegar, the commercial product. On the other hand, Gluconobacter strains have the ability to perform oxidative fermentation of various sugars, sugar alcohols, and sugar acids leading to the formation of several valuable products. Thermotolerant strains of acetic acid bacteria were isolated in order to serve as the new strains of choice for industrial fermentations, in which the cooling costs for maintaining optimum growth and production temperature in the fermentation vessels could be significantly reduced. Genetic modifications by adaptation and genetic engineering were also applied to improve their properties, such as productivity and heat resistance. Copyright © 2014 Elsevier Inc. All rights reserved.
Current status and emerging role of glutathione in food grade lactic acid bacteria
2012-01-01
Lactic acid bacteria (LAB) have taken centre stage in perspectives of modern fermented food industry and probiotic based therapeutics. These bacteria encounter various stress conditions during industrial processing or in the gastrointestinal environment. Such conditions are overcome by complex molecular assemblies capable of synthesizing and/or metabolizing molecules that play a specific role in stress adaptation. Thiols are important class of molecules which contribute towards stress management in cell. Glutathione, a low molecular weight thiol antioxidant distributed widely in eukaryotes and Gram negative organisms, is present sporadically in Gram positive bacteria. However, new insights on its occurrence and role in the latter group are coming to light. Some LAB and closely related Gram positive organisms are proposed to possess glutathione synthesis and/or utilization machinery. Also, supplementation of glutathione in food grade LAB is gaining attention for its role in stress protection and as a nutrient and sulfur source. Owing to the immense benefits of glutathione, its release by probiotic bacteria could also find important applications in health improvement. This review presents our current understanding about the status of glutathione and its role as an exogenously added molecule in food grade LAB and closely related organisms. PMID:22920585
NASA Astrophysics Data System (ADS)
He, Shengbin; Hong, Xinyi; Huang, Tianxun; Zhang, Wenqiang; Zhou, Yingxing; Wu, Lina; Yan, Xiaomei
2017-06-01
A laboratory-built high-sensitivity flow cytometer (HSFCM) was employed for the rapid and accurate detection of lactic acid bacteria (LAB) and their viability in probiotic products. LAB were stained with both the cell membrane-permeable SYTO 9 green-fluorescent nucleic acid stain and the red-fluorescent nucleic acid stain, propidium iodide, which penetrates only bacteria with compromised membranes. The side scatter and dual-color fluorescence signals of single bacteria were detected simultaneously by the HSFCM. Ultra-high temperature processing milk and skim milk spiked with Lactobacillus casei were used as the model systems for the optimization of sample pretreatment and staining. The viable LAB counts measured by the HSFCM were in good agreement with those of the plate count method, and the measured ratios between the live and dead LAB matched well with the theoretical ratios. The established method was successfully applied to the rapid quantification of live/dead LAB in yogurts and fermented milk beverages of different brands. Moreover, the concentration and viability status of LAB in ambient yogurt, a relatively new yet popular milk product in China, are also reported.
Ruiz Rodríguez, L; Vera Pingitore, E; Rollan, G; Martos, G; Saavedra, L; Fontana, C; Hebert, E M; Vignolo, G
2016-08-01
Spontaneous fermented sourdoughs prepared from amaranth flour were investigated for the presence of autochthonous lactic acid bacteria (LAB) predominating microbiota. The doughs were fermented with daily backslopping on a laboratory scale at 30°C for 10 days. LAB counts ranged from 2·60 to 8·54 log CFU g(-1) with a pH declined from 6·2 to 3·8 throughout fermentation. The combined use of randomly amplified polymorphic DNA (RAPD)-PCR analysis and sequence analysis of 16S rRNA was applied for LAB intraspecies differentiation and taxonomic identification, respectively. Enterococcus, Pediococcus and Lactobacillus species were present in amaranth sourdoughs (AS). After the first refreshment step, Lactobacillus plantarum dominated AS until the end of fermentation. In coincidence, when DGGE analysis was performed, the occurrence of a progressive change in bacterial communities allowed the selection of Lact. plantarum as a dominant species. Moreover, technological, functional and safety characteristics of representative RAPD-biotypes were investigated. Lact. plantarum CRL1898 was selected as a potential candidate for gluten-free amaranth sourdough starter. Nowadays, there is an increasing interest in ancient noncereal gluten-free (GF) crops such as amaranth, due to their reported nutritional and health benefits. However, the use of these grains is still limited to traditional foods and bread making processes that are not yet well standardized. Results on the dynamics of autochthonous lactic acid bacteria (LAB) microbiota during laboratory spontaneous amaranth sourdoughs (AS) fermentation will contribute to overcome challenges for GF-fermented products development. In addition, knowledge about LAB diversity involving Enterococcus, Pediococcus and Lactobacillus species, with Lactobacillus plantarum predominating during AS fermentation, and their technological and functional properties provides the basis for the selection of autochthonous strains as starters cultures
Zheng, Xufeng; Fu, Nan; Duan, Manlei; Woo, Meng Wai; Selomulya, Cordelia; Chen, Xiao Dong
2015-10-01
Reconstituted skim milk (RSM) is a reputed protective carrier for improving the survival ratio of lactic acid bacteria (LAB) after spray drying; however the underlying mechanisms of the prominent protection remains unclear. In this study, the inactivation histories of two LAB strains during droplet drying with four carriers were experimentally determined, and the effects of droplet drying parameters on LAB inactivation were investigated. For the first time, the possible contribution of each RSM components to the maintenance of LAB viability during drying was discussed. Rapid inactivation of LAB cells only started at the later stage of drying, where RSM could maintain viability better upon both high droplet temperature and low moisture content than the other three carriers tested. Such protective effects was attributed to calcium and milk proteins rather than lactose. Upon the rapidly increasing droplet temperature at the later stage, calcium might enhance the heat resistance of LAB cells, whereas proteins might lead to a mild temperature variation rate which was beneficial to cell survival. LAB cells dried in the reconstituted whole milk showed the most advanced transition of rapid viability loss, with transition temperature at around 60°C, in contrast to 65-70°C in lactose and MRS carriers and 75°C in the RSM carrier. The detrimental effects could be due to the high level of milk fat content. The proposed effects of each RSM components on LAB viability would be useful for constructing more powerful protectants for production of active dry LAB cells via spray drying. Copyright © 2015 Elsevier Ltd. All rights reserved.
Effects of lactic acid bacteria contamination on lignocellulosic ethanol fermentation
USDA-ARS?s Scientific Manuscript database
Slower fermentation rates, mixed sugar compositions, and lower sugar concentrations may make lignocellulosic fermentations more susceptible to contamination by lactic acid bacteria (LAB), which is a common and costly problem to the corn-based fuel ethanol industry. To examine the effects of LAB con...
Heir, Even; Møretrø, Trond; Simensen, Andreas; Langsrud, Solveig
2018-06-20
Interactions and competition between resident bacteria in food processing environments could affect their ability to survive, grow and persist in microhabitats and niches in the food industry. In this study, the competitive ability of L. monocytogenes strains grown together in separate culture mixes with other L. monocytogenes (L. mono mix), L. innocua (Listeria mix), Gram-negative bacteria (Gram- mix) and with a multigenera mix (Listeria + Gram- mix) was investigated in biofilms on stainless steel and in suspensions at 12 °C. The mixed cultures included resident bacteria from processing surfaces in meat and salmon industry represented by L. monocytogenes (n = 6), L. innocua (n = 5) and Gram-negative bacteria (n = 6; Acinetobacter sp., Pseudomonas fragi, Pseudomonas fluorescens, Serratia liquefaciens, Stenotrophomonas maltophilia). Despite hampered in growth in mixed cultures, L. monocytogenes established in biofilms with counts at day nine between 7.3 and 9.0 log per coupon with the lowest counts in the Listeria + G- mix that was dominated by Pseudomonas. Specific L. innocua inhibited growth of L. monocytogenes strains differently; inhibition that was further enhanced by the background Gram-negative microbiota. In these multispecies and multibacteria cultures, the growth competitive effects lead to the dominance of a strong competitor L. monocytogenes strain that was only slightly inhibited by L. innocua and showed strong competitive abilities in mixed cultures with resident Gram-negative bacteria. The results indicates complex patterns of bacterial interactions and L. monocytogenes inhibition in the multibacteria cultures that only partially depend on cell contact and likely involve various antagonistic and bacterial tolerance mechanisms. The study indicates large variations among L. monocytogenes in their competitiveness under multibacterial culture conditions that should be considered in further studies towards understanding of L
Naderi, Atiyeh; Kasra-Kermanshahi, Roha; Gharavi, Sara; Imani Fooladi, Abbas Ali; Abdollahpour Alitappeh, Meghdad; Saffarian, Parvaneh
2014-03-01
Urinary tract infection (UTI) caused by bacteria is one of the most frequent infections in human population. Inappropriate use of antibiotics, often leads to appearance of drug resistance in bacteria. However, use of probiotic bacteria has been suggested as a partial replacement. This study was aimed to assess the antagonistic effects of Lactobacillus standard strains against bacteria isolated from UTI infections. Among 600 samples; those with ≥10,000 cfu/ml were selected as UTI positive samples. Enterococcus sp., Klebsiella pneumoniae, Enterobacter sp., and Escherichia coli were found the most prevalent UTI causative agents. All isolates were screened for multi drug resistance and subjected to the antimicrobial effects of three Lactobacillus strains by using microplate technique and the MICs amounts were determined. In order to verify the origin of antibiotic resistance of isolates, plasmid curing using ethidium bromide and acridine orange was carried out. No antagonistic activity in Lactobacilli suspension was detected against test on Enterococcus and Enterobacter strains and K. pneumoniae, which were resistant to most antibiotics. However, an inhibitory effect was observed for E. coli which were resistant to 8-9 antibiotics. In addition, L. casei was determined to be the most effective probiotic. RESULTS from replica plating suggested one of the plasmids could be related to the gene responsible for ampicillin resistance. Treatment of E. coli with probiotic suspension was not effective on inhibition of the plasmid carrying hypothetical ampicillin resistant gene. Moreover, the plasmid profiles obtained from probiotic-treated isolates were identical to untreated isolates.
Food-associated lactic acid bacteria with antimicrobial potential from traditional Mexican foods.
Alvarado, C; García Almendárez, B E; Martin, S E; Regalado, C
2006-01-01
This work was conducted to identify indigenous LAB capable of antimicrobial activity, present in traditional Mexican-foods with potential as natural preservatives. A total of 27 artisan unlabeled Mexican products were evaluated, from which 94 LAB strains were isolated, and only 25 strains showed antimicrobial activity against at least one pathogen indicator microorganism. Most of the inhibitory activity showed by the isolated LAB strains was attributed to pH reduction by organic acids. Lactobacillus and Lactococcus strains were good acid producers, depending on the substrate, and may enhance the safety of food products. Cell free cultures of Leuconostoc mesenteroides CH210, and PT8 (from chorizo and pulque, respectively) reduced the number of viable cells of enteropathogenic E. coli in broth system. Lb. plantarum CC10 (from "madre" of vinegar) showed significant inhibitory effect against S. aureus 8943. E. faecium QPII (from panela cheese) produced a bacteriocin with wide anti-L. monocytogenes activity. Selected LAB from traditional Mexican foods showed good potential as bio-preservatives.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Jones, Eric D.
1999-06-17
In the world of computer-based data acquisition and control, the graphical interface program LabVIEW from National Instruments is so ubiquitous that in many ways it has almost become the laboratory standard. To date, there have been approximately fifteen books concerning LabVIEW, but Professor Essick's treatise takes on a completely different tack than all of the previous discussions. In the more standard treatments of the ways and wherefores of LabVIEW such as LabVIEW Graphical Programming: Practical Applications in Instrumentation and Control by Gary W. Johnson (McGraw Hill, NY 1997), the emphasis has been instructing the reader how to program LabVIEW tomore » create a Virtual Instrument (VI) on the computer for interfacing to a particular instruments. LabVIEW is written in G a graphical programming language developed by National Instruments. In the past the emphasis has been on training the experimenter to learn G . Without going into details here, G incorporates the usual loops, arithmetic expressions, etc., found in many programming languages, but in an icon (graphical) environment. The net result being that LabVIEW contains all of the standard methods needed for interfacing to instruments, data acquisition, data analysis, graphics, and also methodology to incorporate programs written in other languages into LabVIEW. Historically, according to Professor Essick, he developed a series of experiments for an upper division laboratory course for computer-based instrumentation. His observation was that while many students had the necessary background in computer programming languages, there were students who had virtually no concept about writing a computer program let alone a computer- based interfacing program. Thus the beginnings of a concept for not only teaching computer- based instrumentation techniques, but aiso a method for the beginner to experience writing a com- puter program. Professor Essick saw LabVIEW as the perfect environment in which to teach
DOE Office of Scientific and Technical Information (OSTI.GOV)
Jones, Eric D.
1999-06-17
In the world of computer-based data acquisition and control, the graphical interface program LabVIEW from National Instruments is so ubiquitous that in many ways it has almost become the laboratory standard. To date, there have been approximately fifteen books concerning LabVIEW, but Professor Essick's treatise takes on a completely different tack than all of the previous discussions. In the more standard treatments of the ways and wherefores of LabVIEW such as LabVIEW Graphical Programming: Practical Applications in Instrumentation and Control by Gary W. Johnson (McGraw Hill, NY 1997), the emphasis has been instructing the reader how to program LabVIEW tomore » create a Virtual Instrument (VI) on the computer for interfacing to a particular instruments. LabVIEW is written in "G" a graphical programming language developed by National Instruments. In the past the emphasis has been on training the experimenter to learn "G". Without going into details here, "G" incorporates the usual loops, arithmetic expressions, etc., found in many programming languages, but in an icon (graphical) environment. The net result being that LabVIEW contains all of the standard methods needed for interfacing to instruments, data acquisition, data analysis, graphics, and also methodology to incorporate programs written in other languages into LabVIEW. Historically, according to Professor Essick, he developed a series of experiments for an upper division laboratory course for computer-based instrumentation. His observation was that while many students had the necessary background in computer programming languages, there were students who had virtually no concept about writing a computer program let alone a computer- based interfacing program. Thus the beginnings of a concept for not only teaching computer- based instrumentation techniques, but aiso a method for the beginner to experience writing a com- puter program. Professor Essick saw LabVIEW as the "perfect environment in which to
Luo, W; Chen, M; Chen, A; Dong, W; Hou, X; Pu, B
2015-04-01
To isolate lactic acid bacteria (LAB) from pao cai, a Chinese traditional fermented vegetable, with outstanding inhibitory activity against Salmonella inoculated on fresh-cut apple, using a modelling method. Four kinds of pao cai were selected. A total of 122 isolates exhibited typical LAB characteristics: Gram-positive and catalase negative, among which 104 (85·24%) colonies showed antibacterial activity against Salmonella by the well diffusion assay. Four colonies showing maximum antibacterial radius against Salmonella were selected to co-inoculate with Salmonella on fresh-cut apple and stored at 10°C, further identified as three strains of Lactobacillus plantarum and one strain of Lactobacillus brevis by 16s rRNA gene sequence analysis. The modified Gompertz model was employed to analyse the growth of the micro-organisms on apple wedges. Two of the four selected strains showed antagonistic activity against Salmonella on fresh-cut apple, one of which, RD1, exhibited best inhibitory activity (Salmonella were greatly inhibited when co-inoculated with RD1 at 10°C at 168 h). No deterioration in odour or appearance of the apple piece was observed by the triangle test when fresh-cut apple was inoculated with RD1. The mathematical modelling method is essential to select LAB with outstanding inhibitory activity against Salmonella associated with fresh-cut apple. LAB RD1 holds promise for the preservation of fresh-cut apple. This study provided a new method on fresh-cut product preservation. Besides, to make the LAB isolating procedure a more correct one, this study first added the mathematical modelling method to the isolating procedure. © 2014 The Society for Applied Microbiology.
Dar, Shabir A.; Kleerebezem, Robbert; Stams, Alfons J. M.; Kuenen, J. Gijs
2008-01-01
The microbial population structure and function of natural anaerobic communities maintained in lab-scale continuously stirred tank reactors at different lactate to sulfate ratios and in the absence of sulfate were analyzed using an integrated approach of molecular techniques and chemical analysis. The population structure, determined by denaturing gradient gel electrophoresis and by the use of oligonucleotide probes, was linked to the functional changes in the reactors. At the influent lactate to sulfate molar ratio of 0.35 mol mol−1, i.e., electron donor limitation, lactate oxidation was mainly carried out by incompletely oxidizing sulfate-reducing bacteria, which formed 80–85% of the total bacterial population. Desulfomicrobium- and Desulfovibrio-like species were the most abundant sulfate-reducing bacteria. Acetogens and methanogenic Archaea were mostly outcompeted, although less than 2% of an acetogenic population could still be observed at this limiting concentration of lactate. In the near absence of sulfate (i.e., at very high lactate/sulfate ratio), acetogens and methanogenic Archaea were the dominant microbial communities. Acetogenic bacteria represented by Dendrosporobacter quercicolus-like species formed more than 70% of the population, while methanogenic bacteria related to uncultured Archaea comprising about 10–15% of the microbial community. At an influent lactate to sulfate molar ratio of 2 mol mol−1, i.e., under sulfate-limiting conditions, a different metabolic route was followed by the mixed anaerobic community. Apparently, lactate was fermented to acetate and propionate, while the majority of sulfidogenesis and methanogenesis were dependent on these fermentation products. This was consistent with the presence of significant levels (40–45% of total bacteria) of D. quercicolus-like heteroacetogens and a corresponding increase of propionate-oxidizing Desulfobulbus-like sulfate-reducing bacteria (20% of the total bacteria). Methanogenic
2016-01-01
In this study, traditional culture method and 16S rRNA gene analysis were applied to reveal the composition and diversity of lactic acid bacteria (LAB) of fermented cow milk, huruud and urum from Baotou and Bayannur of midwestern Inner Mongolia. Also, the quantitative results of dominant LAB species in three different types of dairy products from Baotou and Bayannur were gained by quantitative polymerase chain reaction (q-PCR) technology. Two hundred and two LAB strains isolated from sixty-six samples were identified and classified into four genera, namely Enterococcus, Lactococcus, Lactobacillus, Leuconostoc, and twenty-one species and subspecies. From these isolates, Lactococcus lactis subsp. lactis (32.18%), Lactobacillus plantarum (12.38%) and Leuconosto mesenteroides (11.39%) were considered as the dominated LAB species under the condition of cultivating in MRS and M17 medium. And the q-PCR results revealed that the number of dominant species varied from samples to samples and from region to region. This study clearly shows the composition and diversity of LAB existing in fermented cow milk, huruud and urum, which could be considered as valuable resources for LAB isolation and further probiotic selection. PMID:27621691
Plasmids from Food Lactic Acid Bacteria: Diversity, Similarity, and New Developments
Cui, Yanhua; Hu, Tong; Qu, Xiaojun; Zhang, Lanwei; Ding, Zhongqing; Dong, Aijun
2015-01-01
Plasmids are widely distributed in different sources of lactic acid bacteria (LAB) as self-replicating extrachromosomal genetic materials, and have received considerable attention due to their close relationship with many important functions as well as some industrially relevant characteristics of the LAB species. They are interesting with regard to the development of food-grade cloning vectors. This review summarizes new developments in the area of lactic acid bacteria plasmids and aims to provide up to date information that can be used in related future research. PMID:26068451
Gibbs, Daunte S.; Anderson, Gary L.; Beuchat, Larry R.; Carta, Lynn K.; Williams, Phillip L.
2005-01-01
Diploscapter, a thermotolerant, free-living soil bacterial-feeding nematode commonly found in compost, sewage, and agricultural soil in the United States, was studied to determine its potential role as a vehicle of Salmonella enterica serotype Poona, enterohemorrhagic Escherichia coli O157:H7, and Listeria monocytogenes in contaminating preharvest fruits and vegetables. The ability of Diploscapter sp. strain LKC25 to survive on agar media, in cow manure, and in composted turkey manure and to be attracted to, ingest, and disperse food-borne pathogens inoculated into soil or a mixture of soil and composted turkey manure was investigated. Diploscapter sp. strain LKC25 survived and reproduced in lawns of S. enterica serotype Poona, E. coli O157:H7, and L. monocytogenes on agar media and in cow manure and composted turkey manure. Attraction of Diploscapter sp. strain LKC25 to colonies of pathogenic bacteria on tryptic soy agar within 10, 20, 30, and 60 min and 24 h was determined. At least 85% of the worms initially placed 0.5 to 1 cm away from bacterial colonies migrated to the colonies within 1 h. Within 24 h, ≥90% of the worms were embedded in colonies. The potential of Diploscapter sp. strain LKC25 to shed pathogenic bacteria after exposure to bacteria inoculated into soil or a mixture of soil and composted turkey manure was investigated. Results indicate that Diploscapter sp. strain LKC25 can shed pathogenic bacteria after exposure to pathogens in these milieus. They also demonstrate its potential to serve as a vector of food-borne pathogenic bacteria in soil, with or without amendment with compost, to the surface of preharvest fruits and vegetables in contact with soil. PMID:15870330
Portable Anthrax Testing with Lab-in-a-Pocket
Finley, Melissa; Koskelo, Markku; Edwards, Thayne
2018-05-30
BaDx (Bacillus anthracis Diagnostics) is a lab-in-a-pocket device to sample, sense, and diagnose bacteria that cause anthrax. It accomplishes these tasks in environments with no power, refrigerated storage, or laboratory equipment. BaDx was designed to be used with minimal or no training, and to keep handlers safe.
Portable Anthrax Testing with Lab-in-a-Pocket
DOE Office of Scientific and Technical Information (OSTI.GOV)
Finley, Melissa; Koskelo, Markku; Edwards, Thayne
2014-10-24
BaDx (Bacillus anthracis Diagnostics) is a lab-in-a-pocket device to sample, sense, and diagnose bacteria that cause anthrax. It accomplishes these tasks in environments with no power, refrigerated storage, or laboratory equipment. BaDx was designed to be used with minimal or no training, and to keep handlers safe.
NASA Astrophysics Data System (ADS)
Susilowati, Agustine; Aspiyanto, Maryati, Yati; Melanie, Hakiki; Lotulung, Puspa D.
2017-01-01
Purifying broccoli (Brassica oleracea L.) fermented by Lactic Acid Bacteria (LAB) using mixture of L. bulgaricus, S. thermopillus, L. acidophillusand Bifidobacteriumbifidum and fructooligosaccharides (FOS) as carbon source have been performed to recover biomass concentrate for probiotic and antioxidant. Purification of fermented broccoli was conducted through microfiltration (MF) membrane of 0.15 µm at stirrer rotation speed 400 rpm, room temperature and pressure 40 psia for 30 minutes. Fermented broccoli produced via fermentation process with fermentation time 0 (initial) and 48 hours, and LAB concentration 10% and 20% (v/v) represented as biomass of A, B, C and D. The experimental result showed that based on selectivity of total organic acids, separating optimization was achieved at biomass D (fermentation time 48 hours and mixed LAB culture concentration 20%). Concentrate composition produced in this condition were total acids 6.04%, total solids 24.31%, total polyphenol 0.0252%, reducing sugar 68.25 mg/mL, total sugars 30.89 mg/mL, and dissolved protein 28.54 mg/mL with pH 3.94. In this condition, recovery of biomass concentrate of D for total acids 5.64 folds, total solids 1.82 folds, total polyphenol 3.03 folds, reducing sugar 1.16 folds, total sugars 1.19 folds, and dissolved protein 0.67 folds compared with feed (initial process). Identification of monomer of biomass concentrate D as polyphenol derivatives at T2,01 and T3.01 gave monomer with molecular weight (MW) 192.78 Dalton (Da.), and monomer with MW 191.08, 191.49 and 192.07 Da., while lactic acid derivatives showed MW 251.13, 251.6 and 252.14, and monomer with MW 250.63, 252.14 and 254.22 Da.
Heterologous surface display on lactic acid bacteria: non-GMO alternative?
Zadravec, Petra; Štrukelj, Borut; Berlec, Aleš
2015-01-01
Lactic acid bacteria (LAB) are food-grade hosts for surface display with potential applications in food and therapy. Alternative approaches to surface display on LAB would avoid the use of recombinant DNA technology and genetically-modified organism (GMO)-related regulatory requirements. Non-covalent surface display of proteins can be achieved by fusing them to various cell-wall binding domains, of which the Lysine motif domain (LysM) is particularly well studied. Fusion proteins have been isolated from recombinant bacteria or from their growth medium and displayed on unmodified bacteria, enabling heterologous surface display. This was demonstrated on non-viable cells devoid of protein content, termed bacteria-like particles, and on various species of genus Lactobacillus. Of the latter, Lactobacillus salivarius ATCC 11741 was recently shown to be particularly amenable for LysM-mediated display. Possible regulatory implications of heterologous surface display are discussed, particularly those relevant for the European Union.
Marshall, Pamela A
2007-01-01
In our Fundamentals of Genetics lab, students perform a wide variety of labs to reinforce and extend the topics covered in lecture. I developed an active-learning lab to augment the lecture topic of mutagenesis. In this lab exercise, students determine if a compound they bring from home is a mutagen. Students are required to read extensive background material, perform research to find a potential mutagen to test, develop a hypothesis, and bring to the lab their own suspected mutagen. This lab uses a specially developed strain of Saccharomyces cerevisiae, D7, to determine if a compound is a mutagen. Mutagenesis of the D7 genome can lead to a scorable alteration in the phenotypes of this strain. Students outline and carry out a protocol for treatment of the yeast tester strain, utilizing the concept of dose/response and positive and negative controls. Students report on their results using a PowerPoint presentation to simulate giving a scientific presentation. The students' self-assessment of their knowledge indicated that, in all cases, the students felt that they knew more about the assay, mutagenesis, and the relationship between genotype and phenotype (P < 0.05) after completing the exercise.
Lee, Joon; Yang, Woo; Hostetler, Andrew; Schultz, Nathan; Suckow, Mark A; Stewart, Kay L; Kim, Daniel D; Kim, Hyung Soo
2016-04-19
The gut microbiota is playing more important roles in host immune regulation than was initially expected. Since many benefits of microbes are highly strain-specific and their mechanistic details remain largely elusive, further identification of new probiotic bacteria with immunoregulatory potentials is of great interest. We have screened our collection of probiotic lactic acid bacteria (LAB) for their efficacy in modulating host immune response. Some LAB are characterized by suppression of TNF-α induction when LAB culture supernatants are added to THP-1 cells, demonstrating the LAB's anti-inflammatory potential. These suppressive materials were not inactivated by heat or trypsin. On the other hand, treatment of THP-1 directly with live bacterial cells identified a group of pro-inflammatory LAB, which stimulated significant production of TNF-α. Among those, we chose the Lactobacillus reuteri BM36301 as an anti-inflammatory strain and the L. reuteri BM36304 as a pro-inflammatory strain, and further studied their in vivo effects. We supplied C57BL/6 mice with these bacteria in drinking water while feeding them a standard diet for 20 weeks. Interestingly, these L. reuteri strains evoked different consequences depending on the gender of the mice. That is, males treated with anti-inflammatory BM36301 experienced less weight gain and higher testosterone level; females treated with BM36301 maintained lower serum TNF-α as well as healthy skin with active folliculogenesis and hair growth. Furthermore, while males treated with pro-inflammatory BM36304 developed higher serum levels of TNF-α and insulin, in contrast females did not experience such effects from this bacteria strain. The L. reuteri BM36301 was selected as an anti-inflammatory strain in vitro. It helped mice maintain healthy conditions as they aged. These findings propose the L. reuteri BM36301 as a potential probiotic strain to improve various aspects of aging issues.
Siroli, Lorenzo; Patrignani, Francesca; Serrazanetti, Diana I; Tabanelli, Giulia; Montanari, Chiara; Gardini, Fausto; Lanciotti, Rosalba
2015-05-01
Outbreaks of food-borne disease associated with the consumption of fresh and minimally processed fruits and vegetables have increased dramatically over the last few years. Traditional chemical sanitizers are unable to completely eradicate or kill the microorganisms on fresh produce. These conditions have stimulated research to alternative methods for increasing food safety. The use of protective cultures, particularly lactic acid bacteria (LAB), has been proposed for minimally processed products. However, the application of bioprotective cultures has been limited at the industrial level. From this perspective, the main aims of this study were to select LAB from minimally processed fruits and vegetables to be used as biocontrol agents and then to evaluate the effects of the selected strains, alone or in combination with natural antimicrobials (2-(E)-hexenal/hexanal, 2-(E)-hexenal/citral for apples and thyme for lamb's lettuce), on the shelf-life and safety characteristics of minimally processed apples and lamb's lettuce. The results indicated that applying the Lactobacillus plantarum strains CIT3 and V7B3 to apples and lettuce, respectively, increased both the safety and shelf-life. Moreover, combining the selected strains with natural antimicrobials produced a further increase in the shelf-life of these products without detrimental effects on the organoleptic qualities. Copyright © 2014 Elsevier Ltd. All rights reserved.
Reflections on Three Corporate Research Labs: Bell Labs, HP Labs, Agilent Labs
NASA Astrophysics Data System (ADS)
Hollenhorst, James
2008-03-01
This will be a personal reflection on corporate life and physics-based research in three industrial research labs over three decades, Bell Labs during the 1980's, HP Labs during the 1990's, and Agilent Labs during the 2000's. These were times of great change in all three companies. I'll point out some of the similarities and differences in corporate cultures and how this impacted the research and development activities. Along the way I'll mention some of the great products that resulted from physics-based R&D.
Simova, E D; Beshkova, D B; Dimitrov, Zh P
2009-02-01
To isolate bacteriocin-producing lactic acid bacteria (LAB) with high wide spectrum antibacterial activity and to characterize their inhibitory peptides. Seven LAB strains [Lactobacillus casei ssp. rhamnosus (PC5), Lactobacillus delbrueckii ssp. bulgaricus (BB18), Lactococcus lactis ssp. lactis (BCM5, BK15), Enterococcus faecium (MH3), Lactobacillus plantarum (BR12), Lactobacillus casei ssp. casei (BCZ2)], isolated from authentic Bulgarian dairy products were capable of producing bacteriocins, inhibiting the widest range of pathogenic bacteria. The bacteriocins were resistant to heating at 121 degrees C for 15 min, stable at pH 2-10, sensitive to protease, insensitive to alpha-amylase and lipase. Two of bacteriocins produced by Lact. bulgaricus BB18 (bulgaricin BB18) and E. faecium MH3 (enterocin MH3) were purified and the molecular masses were determined. The N-terminal amino acid sequence of bulgaricin BB18 did not show strong homology to other known bacteriocins. Lactobacillus bulgaricus BB18 and E. faecium MH3 produce two novel bacteriocins highly similar to the pediocin-like nonlantibiotics. The two bacteriocins are potential antimicrobial agents and, in conjunction with their producers, may have use in applications to contribute a positive effect on the balance of intestinal microflora. Furthermore, bulgaricin BB18 strongly inhibits Helicobacter pylori.
Berkhoff, H A; Riddle, G D
1984-01-01
Although standard biochemical tests used for the identification of Alcaligenes spp. revealed only minor differences, the oxidative low-peptone technique clearly differentiated between Alcaligenes-like bacteria of avian origin and Alcaligenes spp. reference strains. Based on their colonial morphology, biochemical profiles, and hemagglutination, the Alcaligenes-like bacteria of avian origin were further divided into two subgroups, C1-T1 and C2-T2. Colonies of subgroup C1-T1 were nondescript, round, raised, glistening, translucent, greyish, and about 2 mm in diameter. Colonies of subgroup C2-T2 were off-white, flat, dry and wrinkled, generally round, and resembled tiny lily pads. Biochemical profiles by the oxidative low-peptone method showed the C1-T1 subgroup alkalinizing only three substrates (citrate, acetate, and succinate), whereas the C2-T2 subgroup alkalinized eight substrates (citrate, acetate, butyrate, itaconate, malonate, saccharate, succinate, and M-tartrate). Subgroup C1-T1 agglutinated human, chicken, and turkey erythrocytes, whereas subgroup C2-T2 did not. The recognition of these two subgroups within the Alcaligenes-like bacteria of avian origin is important, since it may explain the differences seen in pathogenicity among isolates. Images PMID:6715517
Berkhoff, H A; Riddle, G D
1984-04-01
Although standard biochemical tests used for the identification of Alcaligenes spp. revealed only minor differences, the oxidative low-peptone technique clearly differentiated between Alcaligenes-like bacteria of avian origin and Alcaligenes spp. reference strains. Based on their colonial morphology, biochemical profiles, and hemagglutination, the Alcaligenes-like bacteria of avian origin were further divided into two subgroups, C1-T1 and C2-T2. Colonies of subgroup C1-T1 were nondescript, round, raised, glistening, translucent, greyish, and about 2 mm in diameter. Colonies of subgroup C2-T2 were off-white, flat, dry and wrinkled, generally round, and resembled tiny lily pads. Biochemical profiles by the oxidative low-peptone method showed the C1-T1 subgroup alkalinizing only three substrates (citrate, acetate, and succinate), whereas the C2-T2 subgroup alkalinized eight substrates (citrate, acetate, butyrate, itaconate, malonate, saccharate, succinate, and M-tartrate). Subgroup C1-T1 agglutinated human, chicken, and turkey erythrocytes, whereas subgroup C2-T2 did not. The recognition of these two subgroups within the Alcaligenes-like bacteria of avian origin is important, since it may explain the differences seen in pathogenicity among isolates.
Alkaline phosphatase activity of rumen bacteria.
Cheng, K J; Costerton, J W
1977-11-01
Of the 54 strains of rumen bacteria examined for alkaline phosphatase (APase) production, 9 of 33 gram-negative strains and none of 21 gram-positive strains produced the enzyme. The APase of the cells of the three strains of Bacteroides ruminicola that produced significant amounts of the enzyme was located in the periplasmic area of the cell envelope, whereas the enzyme was located in the strains of Selenomonas ruminantium and Succinivibrio dextrinosolvens was associated with the outer membrane. The localization of APase production in the cells of natural populations of rumen bacteria from hay-fed sheep was accomplished by reaction product deposition, and both the proportion of APase-producing bacteria and the location of the enzyme in the cell envelope of the producing cells could be determined. We suggest that this procedure is useful in detecting shifts in the bacterial population and the release of cell-bound APase that accompany feedlot bloat and other sequelae of dietary manipulation in ruminants.
Alkaline phosphatase activity of rumen bacteria.
Cheng, K J; Costerton, J W
1977-01-01
Of the 54 strains of rumen bacteria examined for alkaline phosphatase (APase) production, 9 of 33 gram-negative strains and none of 21 gram-positive strains produced the enzyme. The APase of the cells of the three strains of Bacteroides ruminicola that produced significant amounts of the enzyme was located in the periplasmic area of the cell envelope, whereas the enzyme was located in the strains of Selenomonas ruminantium and Succinivibrio dextrinosolvens was associated with the outer membrane. The localization of APase production in the cells of natural populations of rumen bacteria from hay-fed sheep was accomplished by reaction product deposition, and both the proportion of APase-producing bacteria and the location of the enzyme in the cell envelope of the producing cells could be determined. We suggest that this procedure is useful in detecting shifts in the bacterial population and the release of cell-bound APase that accompany feedlot bloat and other sequelae of dietary manipulation in ruminants. Images PMID:563216
Interaction between lactic acid bacteria and yeasts in airag, an alcoholic fermented milk.
Sudun; Wulijideligen; Arakawa, Kensuke; Miyamoto, Mari; Miyamoto, Taku
2013-01-01
The interaction between nine lactic acid bacteria (LAB) and five yeast strains isolated from airag of Inner Mongolia Autonomic Region, China was investigated. Three representative LAB and two yeasts showed symbioses were selected and incubated in 10% (w/v) reconstituted skim milk as single and mixed cultures to measure viable count, titratable acidity, ethanol and sugar content every 24 h for 1 week. LAB and yeasts showed high viable counts in the mixed cultures compared to the single cultures. Titratable acidity of the mixed cultures was obviously enhanced compared with that of the single cultures, except for the combinations of Lactobacillus reuteri 940B3 with Saccharomyces cerevisiae 4C and Lactobacillus helveticus 130B4 with Candida kefyr 2Y305. C. kefyr 2Y305 produced large amounts of ethanol (maximum 1.35 g/L), whereas non-lactose-fermenting S. cerevisiae 4C produced large amounts of ethanol only in the mixed cultures. Total glucose and galactose content increased while lactose content decreased in the single cultures of Leuconostoc mesenteroides 6B2081 and Lb. helveticus 130B4. However, both glucose and galactose were completely consumed and lactose was markedly reduced in the mixed cultures with yeasts. The result suggests that yeasts utilize glucose and galactose produced by LAB lactase to promote cell growth. © 2012 The Authors. Animal Science Journal © 2012 Japanese Society of Animal Science.
Carey, Christine M; Kostrzynska, Magdalena
2013-01-01
Inflammation is a physiological response to infections and tissue injury; however, abnormal immune responses can give rise to chronic inflammation and contribute to disease progression. Various dietary components, including probiotic lactic acid bacteria and prebiotics, have the potential to modulate intestinal inflammatory responses. One factor in particular, the chemokine interleukin-8 (IL-8, CXCL-8), is one of the major mediators of the inflammatory response. The purpose of this study was to investigate modulation of the inflammatory host response induced by Salmonella enterica serovar Typhimurium DT104 in the presence of selected probiotics and lactic acid bacteria (LAB) isolated from human sources, dairy products, and farm animals. IL-8 gene expression and protein production in HT-29 cells were evaluated by real-time PCR and ELISA, respectively. Pre-incubation of HT-29 cells with Lactobacillus kefir IM002, Bifidobacterium adolescentis FRP 61, Bifidobacterium longum FRP 68 and FRP 69, Bifidobacterium breve FRP 334, and Leuconostoc mesenteroides IM080 significantly inhibited IL-8 secretion induced by Salmonella Typhimurium DT104. Co-culture of selected probiotics and Salmonella Typhimurium DT104 reduced IL-8 production, while potential probiotics and LAB had no effect on IL-8 secretion in HT-29 cells preincubated with Salmonella Typhimurium DT104 prior to adding probiotics. Lactobacillus kefir IM002 supernatant also significantly reduced IL-8 production. In conclusion, our study suggests that probiotic bifidobacteria and LAB modulate cytokine induction and possess anti-inflammatory properties; however, the effectiveness is strain dependent.
Bernbom, Nete; Ng, Yoke Yin; Kjelleberg, Staffan; Harder, Tilmann; Gram, Lone
2011-12-01
The aims of this study were to determine if marine bacteria from Danish coastal waters produce antifouling compounds and if antifouling bacteria could be ascribed to specific niches or seasons. We further assess if antibacterial effect is a good proxy for antifouling activity. We isolated 110 bacteria with anti-Vibrio activity from different sample types and locations during a 1-year sampling from Danish coastal waters. The strains were identified as Pseudoalteromonas, Phaeobacter, and Vibrionaceae based on phenotypic tests and partial 16S rRNA gene sequence similarity. The numbers of bioactive bacteria were significantly higher in warmer than in colder months. While some species were isolated at all sampling locations, others were niche specific. We repeatedly isolated Phaeobacter gallaeciensis at surfaces from one site and Pseudoalteromonas tunicata at two others. Twenty-two strains, representing the major taxonomic groups, different seasons, and isolation strategies, were tested for antiadhesive effect against the marine biofilm-forming bacterium Pseudoalteromonas sp. strain S91 and zoospores of the green alga Ulva australis. The antiadhesive effects were assessed by quantifying the number of strain S91 or Ulva spores attaching to a preformed biofilm of each of the 22 strains. The strongest antifouling activity was found in Pseudoalteromonas strains. Biofilms of Pseudoalteromonas piscicida, Pseudoalteromonas tunicata, and Pseudoalteromonas ulvae prevented Pseudoalteromonas S91 from attaching to steel surfaces. P. piscicida killed S91 bacteria in the suspension cultures, whereas P. tunicata and P. ulvae did not; however, they did prevent adhesion by nonbactericidal mechanism(s). Seven Pseudoalteromonas species, including P. piscicida and P. tunicata, reduced the number of settling Ulva zoospores to less than 10% of the number settling on control surfaces. The antifouling alpP gene was detected only in P. tunicata strains (with purple and yellow pigmentation), so
Heterologous surface display on lactic acid bacteria: non-GMO alternative?
Zadravec, Petra; Štrukelj, Borut; Berlec, Aleš
2015-01-01
Lactic acid bacteria (LAB) are food-grade hosts for surface display with potential applications in food and therapy. Alternative approaches to surface display on LAB would avoid the use of recombinant DNA technology and genetically-modified organism (GMO)-related regulatory requirements. Non-covalent surface display of proteins can be achieved by fusing them to various cell-wall binding domains, of which the Lysine motif domain (LysM) is particularly well studied. Fusion proteins have been isolated from recombinant bacteria or from their growth medium and displayed on unmodified bacteria, enabling heterologous surface display. This was demonstrated on non-viable cells devoid of protein content, termed bacteria-like particles, and on various species of genus Lactobacillus. Of the latter, Lactobacillus salivarius ATCC 11741 was recently shown to be particularly amenable for LysM-mediated display. Possible regulatory implications of heterologous surface display are discussed, particularly those relevant for the European Union. PMID:25880164
Zhu, Peng; Zheng, Li; Li, Jing; Shao, Jian-zhong; Yan, Xiao-jun
2007-04-01
Antibacterial and cytotoxic activities were screened for marine bacteria which have been isolated from organism, sediments and seawater in China coastal area. The results showed that 42 isolates had antimicrobial activity and 12 isolates had cytotoxicity. Molecular phylogenetic analysis of marine bacteria with cytotoxicity based on 16S rRNA sequences indicated that they were belong to the genera Aerococcus, Agrobacterium, Alteromona, Bacillus, Exiguobacterium, Paracoccus, Pseudoalteromons, Rheinheimera. Furthermore, marine bacteria with cytotoxicity were also screened for PKS I and NRPS genes which could be responsible for bioactive secondary metabolites biosynthesis, 4 strains having KS domain or A domain were obtained, which provide strong evidence that marine bioactive bacteria can produce natural products through PKS and NRPS pathways.
Lactic acid bacteria found in fermented fish in Thailand.
Tanasupawat, Somboon; Okada, Sanae; Komagata, Kazuo
1998-06-01
Forty-seven strains of homofermentative rod-shaped and 5 heterofermentative sphere-shaped lactic acid bacteria were isolated from 4 kinds of fermented fish (pla-ra, pla-chom, kung-chom, and hoi-dong) in Thailand. These bacteria were separated into four groups by phenotypic and chemotaxonomic characteristics, including fluorometric DNA-DNA hybridization. Five strains (Group I) contained meso-diaminopimelic acid in the cell wall. Four strains were identified as Lactobacillus pentosus, and one strain was L. plantarum. Tested strains of this group produced DL-lactic acid. The rest of the rod-shaped bacteria, 23 strains (Group II) and 19 strains (Group III), lacked meso-diaminopimelic acid in the cell wall and were identified as L. farciminis and Lactobacillus species, respectively. The tested strains of these groups produced L-lactic acid. The amount of cellular fatty acids of C16:0 and C18:1, and the DNA base compositions were significant for differentiating the strains in Groups II and III. Five strains of cocci in chains (Group IV) produced gas from glucose. The tested strains of this group produced d-lactic acid. They were identified as a Leuconostoc species. The distribution of these bacteria in fermented fish in Thailand is discussed.
Antibiotic resistance of lactic acid bacteria isolated from dry-fermented sausages.
Fraqueza, Maria João
2015-11-06
Dry-fermented sausages are meat products highly valued by many consumers. Manufacturing process involves fermentation driven by natural microbiota or intentionally added starter cultures and further drying. The most relevant fermentative microbiota is lactic acid bacteria (LAB) such as Lactobacillus, Pediococcus and Enterococcus, producing mainly lactate and contributing to product preservation. The great diversity of LAB in dry-fermented sausages is linked to manufacturing practices. Indigenous starters development is considered to be a very promising field, because it allows for high sanitary and sensorial quality of sausage production. LAB have a long history of safe use in fermented food, however, since they are present in human gastrointestinal tract, and are also intentionally added to the diet, concerns have been raised about the antimicrobial resistance in these beneficial bacteria. In fact, the food chain has been recognized as one of the key routes of antimicrobial resistance transmission from animal to human bacterial populations. The World Health Organization 2014 report on global surveillance of antimicrobial resistance reveals that this issue is no longer a future prediction, since evidences establish a link between the antimicrobial drugs use in food-producing animals and the emergence of resistance among common pathogens. This poses a risk to the treatment of nosocomial and community-acquired infections. This review describes the possible sources and transmission routes of antibiotic resistant LAB of dry-fermented sausages, presenting LAB antibiotic resistance profile and related genetic determinants. Whenever LAB are used as starters in dry-fermented sausages processing, safety concerns regarding antimicrobial resistance should be addressed since antibiotic resistant genes could be mobilized and transferred to other bacteria. Copyright © 2015 Elsevier B.V. All rights reserved.
Filloy, L; Borjas, E; Sierra, A
1981-01-01
Susceptibility to antibiotics of 2060 strains of the following bacteria was studied: Escherichia coli, Klebsiella pneumoniae, Salmonella, Shigella, Proteus, Staphylococcus aureus that were isolated in 1978-79 from different infections in children hospitalized at the Hospital Infantil de Mexico. The antimicrobials submitted to the test of susceptibility were: ampicillin, amikacin, carbenicillin, cephalothin, cefoxitin, chloramphenicol, gentamicin, kanamycin, neomycin and sulfamethoxazole-trimethoprim. Present results are compared with previous studies.
[Screening endophytic bacteria against plant-parasitic nematodes].
Peng, Shuang; Yan, Shuzhen; Chen, Shuanglin
2011-03-01
Plant-parasite nematode is one of the most important pathogens in plant. Our objective is to screen endophytic bacteria against plant-parasitic nematodes from plant. Endophytic bacteria were isolated and screened by testing their metabolite against Bursaphelenchus xylophilus in vitro. Those strains inhibiting B. xylophilus were selected to culture in liquid medium and fermentation conditions were optimized by orthogonal test. The stability of the antinematode substances was evaluated by various. In addition, four strains were identified by 16SrDNA sequence analysis. In total 13 strains of endophytic bacteria secreting antinematode metabolite were isolated from 6 species of plant. The supernatant of the fermentation broth of these endophytic bacteria gave 100% mortality of nematodes after treated as the follows: 1 ml each was mixed with 0.2 ml of the suspension of nematodes (2000 nematodes/ml) then incubated at 250C for 24 h, some of which could led to leakage or dissolution of nematodes. Among them, four strains, BCM2, SZ5, CCM7 and DP1, showed stronger activity than others. The supernatants diluted three times also gave not less than 95% mortality after 24 h treatment, and those from DP1 and SZ5 even gave 100% mortality. The fermentation conditions of the four strains were optimized and the antinematode activity grew up four times after optimization. The antinematode substances of these strains were found stable when treated with protease or heating or stored at 4 degrees C after 100 days, while instable when treated with acid or alkali. DP1 and CCM7 were identified to be Bacillus subtilis, while SZ5 and BCM2 to be Bacillus cereus. Endophytic bacteria secreting antinematode metabolite were found in economic crops. The metabolite of some strains showed strong and stable antinematode activity. Our results indicate the real potential of biocontrol by endophytic bacteria.
Foligné, Benoit; Nutten, Sophie; Steidler, Lothar; Dennin, Véronique; Goudercourt, Denise; Mercenier, Annick; Pot, Bruno
2006-02-01
Probiotic bacteria have been shown to exert promising beneficial effects in different types of intestinal disorders, including chronic inflammation. In this context, animal models of inflammatory bowel disease are useful in studying the possible prophylactic role of candidate probiotic strains. This study aimed at evaluating the critical technological and microbiological parameters as well as the robustness of the murine trinitrobenzene sulfonic acid (TNBS)-induced model of colitis, after intragastric administration of lactic acid bacteria (LAB) preparations. A standardized methodology was applied to assess the protective effect achieved by various bacterial concentrations and culture conditions of the reference strain Lactobacillus plantarum NCIMB 8826. Not only was protection found to vary in function in different levels of colitis, but also repeated experiments showed a clear bacterial dose-dependent attenuation of colitis. The physiological stage of bacteria was shown to impact as well, with substantial, mild, or reduced improvement of inflammatory scores for exponentially growing, stationary-phase, or killed bacteria, respectively. A recombinant strain, secreting murine interleukin-10 (IL-10) and previously reported to successfully treat colitis in two different models of murine colitis (dextran sulfate sodium [DSS] and IL-10-deficient mice), was used to validate the final experimental conditions. In conclusion, we identified and optimized some of the key parameters that need to be controlled in order to ensure reliable comparison of results generated over a long period of time or independent experiments. The recommendations for an improved model presented here will prove to be helpful for reproducible, independent comparison of the anti-inflammatory potential of wild-type or recombinant candidate probiotic strains, whether administered as pure cultures or as blends.
Wang, Yan-Su; Wu, Tian-Hao; Yang, Yao; Zhu, Cen-Ling; Ding, Cheng-Long; Dai, Chuan-Chao
2016-01-01
This investigation examined the reduction of pesticide residues on straw inoculated with lactic acid bacteria (LAB) during ensiling. Lactobacillus casei WYS3 was isolated from rice straw that contained pesticide residues. Non-sterilized rice straw, which was inoculated with L. casei WYS3, showed increased removal of chlorpyrifos after ensiling, compared with rice straw that was not inoculated with L. casei WYS3 or sterilized rice straw. In pure culture, these strains can bind chlorpyrifos as indicated by high-performance liquid chromatography analysis. Viable L. casei WYS3 was shown to bind 33.3-42% of exogenously added chlorpyrifos. These results are similar to those of acid-treated cells but less than those of heat-treated cells, which were found to bind 32.0% and 77.2% of the added chlorpyrifos respectively. Furthermore, gas chromatography-mass spectrometry analysis determined that L. casei WYS3 detoxified chlorpyrifos via P-O-C cleavage. Real-time polymerized chain reaction analysis determined that organophosphorus hydrolase gene expression tripled after the addition of chlorpyrifos to LAB cultures, compared with the control group (without chlorpyrifos). This paper highlights the potential use of LAB starter cultures for the detoxification and removal of chlorpyrifos residues in the environment.
Gram, Lone; Grossart, Hans-Peter; Schlingloff, Andrea; Kiørboe, Thomas
2002-01-01
We report here, for the first time, that bacteria associated with marine snow produce communication signals involved in quorum sensing in gram-negative bacteria. Four of 43 marine microorganisms isolated from marine snow were found to produce acylated homoserine lactones (AHLs) in well diffusion and thin-layer chromatographic assays based on the Agrobacterium tumefaciens reporter system. Three of the AHL-producing strains were identified by 16S ribosomal DNA gene sequence analysis as Roseobacter spp., and this is the first report of AHL production by these α-Proteobacteria. It is likely that AHLs in Roseobacter species and other marine snow bacteria govern phenotypic traits (biofilm formation, exoenzyme production, and antibiotic production) which are required mainly when the population reaches high densities, e.g., in the marine snow community. PMID:12147515
NASA Astrophysics Data System (ADS)
Baniyah, Laelatul; Nur Jannah, Siti; Rukmi, Isworo; Sugiharto
2018-05-01
Lactic Acid Bacteria (LAB) is a digestive tract microflora that have a positive role in poultry health. The number and diversity of LAB in the digestive tract affected by several factors, among them was the kind of feed. The purpose of this research was to know diversity of Lactic Acid Bacteria (LAB) ileum broiler’s after feeding with prebiotic bran and Rhizopus oryzae fermented bran which was added to commercial feed. As much as 15 broilers were used to determine the diversity of LAB. All broilers were fed using commercial feed. The control used commercial feed no addition of bran or fermented bran, and commercial feed with fermented bran and nonfermented bran were as a treatment. To determine the diversity of LAB, T-RFLP method was applied. The Hae III and Msp I were used as restriction enzymes. The number of phylotype, relative abundance, Shannon diversity index (H '), evenness (E), and Dominance (D) were examined. The results indicated that the addition of prebiotic bran on commercial feed showed a higher diversity of lactic acid bacteria on broiler’s ileum, compared with control and addition of Rhizopus oryzae fermented bran. LAB group that dominates in the ileum is Lactobacillus sp. and L. delbruecii subs bulgaricus.
USDA-ARS?s Scientific Manuscript database
Multidrug-resistant (MDR) bacteria are an increasing threat to human and animal health. The objectives of the present study were to determine: (1) the effect of Aureomycin® on MDR E. coli field strains in growing swine fecal fluid; (2) the competitive fitness of each of these strains in long-term c...
USDA-ARS?s Scientific Manuscript database
Lactic acid bacteria (LAB) frequently contaminate commercial fuel ethanol fermentations, reducing yields and decreasing profitability of biofuel production. Microorganisms from environmental sources in different geographic regions of Thailand were tested for antibacterial activity against LAB. Fou...
Magnetic Trapping of Bacteria at Low Magnetic Fields
NASA Astrophysics Data System (ADS)
Wang, Z. M.; Wu, R. G.; Wang, Z. P.; Ramanujan, R. V.
2016-06-01
A suspension of non-magnetic entities in a ferrofluid is referred to as an inverse ferrofluid. Current research to trap non-magnetic entities in an inverse ferrofluid focuses on using large permanent magnets to generate high magnetic field gradients, which seriously limits Lab-on-a-Chip applications. On the other hand, in this work, trapping of non-magnetic entities, e.g., bacteria in a uniform external magnetic field was studied with a novel chip design. An inverse ferrofluid flows in a channel and a non-magnetic island is placed in the middle of this channel. The magnetic field was distorted by this island due to the magnetic susceptibility difference between this island and the surrounding ferrofluid, resulting in magnetic forces applied on the non-magnetic entities. Both the ferromagnetic particles and the non-magnetic entities, e.g., bacteria were attracted towards the island, and subsequently accumulate in different regions. The alignment of the ferrimagnetic particles and optical transparency of the ferrofluid was greatly enhanced by the bacteria at low applied magnetic fields. This work is applicable to lab-on-a-chip based detection and trapping of non-magnetic entities bacteria and cells.
Bernbom, Nete; Ng, Yoke Yin; Kjelleberg, Staffan; Harder, Tilmann; Gram, Lone
2011-01-01
The aims of this study were to determine if marine bacteria from Danish coastal waters produce antifouling compounds and if antifouling bacteria could be ascribed to specific niches or seasons. We further assess if antibacterial effect is a good proxy for antifouling activity. We isolated 110 bacteria with anti-Vibrio activity from different sample types and locations during a 1-year sampling from Danish coastal waters. The strains were identified as Pseudoalteromonas, Phaeobacter, and Vibrionaceae based on phenotypic tests and partial 16S rRNA gene sequence similarity. The numbers of bioactive bacteria were significantly higher in warmer than in colder months. While some species were isolated at all sampling locations, others were niche specific. We repeatedly isolated Phaeobacter gallaeciensis at surfaces from one site and Pseudoalteromonas tunicata at two others. Twenty-two strains, representing the major taxonomic groups, different seasons, and isolation strategies, were tested for antiadhesive effect against the marine biofilm-forming bacterium Pseudoalteromonas sp. strain S91 and zoospores of the green alga Ulva australis. The antiadhesive effects were assessed by quantifying the number of strain S91 or Ulva spores attaching to a preformed biofilm of each of the 22 strains. The strongest antifouling activity was found in Pseudoalteromonas strains. Biofilms of Pseudoalteromonas piscicida, Pseudoalteromonas tunicata, and Pseudoalteromonas ulvae prevented Pseudoalteromonas S91 from attaching to steel surfaces. P. piscicida killed S91 bacteria in the suspension cultures, whereas P. tunicata and P. ulvae did not; however, they did prevent adhesion by nonbactericidal mechanism(s). Seven Pseudoalteromonas species, including P. piscicida and P. tunicata, reduced the number of settling Ulva zoospores to less than 10% of the number settling on control surfaces. The antifouling alpP gene was detected only in P. tunicata strains (with purple and yellow pigmentation), so
Anaerobic bacteria that dechlorinate perchloroethene.
Fathepure, B Z; Nengu, J P; Boyd, S A
1987-01-01
In this study, we identified specific cultures of anaerobic bacteria that dechlorinate perchlorethene (PCE). The bacteria that significantly dechlorinated PCE were strain DCB-1, an obligate anaerobe previously shown to dechlorinate chlorobenzoate, and two strains of Methanosarcina. The rate of PCE dechlorination by DCB-1 compared favorably with reported rates of trichloroethene bio-oxidation by methanotrophs. Even higher PCE dechlorination rates were achieved when DCB-1 was grown in a methanogenic consortium. PMID:3426224
Khota, Waroon; Pholsen, Suradej; Higgs, David; Cai, Yimin
2016-12-01
Natural lactic acid bacteria (LAB) populations in tropical grasses and their fermentation characteristics on silage prepared with cellulase enzyme and LAB inoculants were studied. A commercial inoculant Lactobacillus plantarum Chikuso 1 (CH), a local selected strain Lactobacillus casei TH14 (TH14), and 2 cellulases, Acremonium cellulase (AC) and Maicelase (MC; Meiji Seika Pharma Co. Ltd., Tokyo, Japan), were used as additives to silage preparation with fresh and wilted (6 h) Guinea grass and Napier grass. Silage was prepared using a laboratory-scale fermentation system. Treatments were CH, TH14, AC at 0.01% fresh matter, AC 0.1%, MC 0.01%, MC 0.1%, CH+AC 0.01%, CH+AC 0.1%, CH+MC 0.01%, CH+MC 0.1%, TH14+AC 0.1%, TH14+AC 0.01%, TH14+MC 0.1%, and TH14+MC 0.01%. Microorganism counts of Guinea grass and Napier grass before ensiling were 10 2 LAB and 10 6 aerobic bacteria; these increased during wilting. Based on morphological and biochemical characteristics, and 16S rRNA gene sequence analysis, natural strains from both grasses were identified as L. plantarum, L. casei, Lactobacillus acidipiscis, Leuconostoc pseudomesenteroides, Leuconostoc garlicum, Weissella confusa, and Lactococcus lactis. Lactobacillus plantarum and L. casei are the dominant species and could grow at lower pH and produce more lactic acid than the other isolates. Crude protein and neutral detergent fiber were 5.8 and 83.7% of dry matter (DM) for Guinea grass, and 7.5 and 77.1% of DM for Napier grass. Guinea grass had a low level of water-soluble carbohydrates (0.39% of DM). Guinea grass silage treated with cellulase had a lower pH and higher lactic acid content than control and LAB treatments. The 0.1% AC and MC treatments had the best result for fermentation quality. All high water-soluble carbohydrate (2.38% DM) Napier grass silages showed good fermentation quality. Compared with control and LAB-inoculated silage, the cellulase-treated silages had significantly higher crude protein content and
Biodegradation of chlorpyrifos by lactic acid bacteria during kimchi fermentation.
Cho, Kye Man; Math, Reukaradhya K; Islam, Shah Md Asraful; Lim, Woo Jin; Hong, Su Young; Kim, Jong Min; Yun, Myoung Geun; Cho, Ji Joong; Yun, Han Dae
2009-03-11
We examined the role of microorganisms in the degradation of the organophosphorus (OP) insecticide chlorpyrifos (CP) during kimchi fermentation. During the fermentation of kimchi, 30 mg L(-1) of CP was added and its stability assayed during fermentation. CP was degraded rapidly until day 3 (83.3%) and degraded completely by day 9. Four CP-degrading lactic acid bacteria (LAB) were isolated from kimchi fermentation in the presence of 200 mg L(-1) CP and were identified as Leuconostoc mesenteroides WCP907, Lactobacillus brevis WCP902, Lactobacillus plantarum WCP931, and Lactobacillus sakei WCP904. CP could be utilized by these four strains as the sole source of carbon and phosphorus. Coumaphos (CM), diazinon (DZ), parathion (PT), and methylparathion (MPT) were also degraded by WCP907, WCP902, WCP931, and WCP904 when provided as sole sources of carbon and phosphorus.
NASA Astrophysics Data System (ADS)
Susilowati, Agustine; Melanie, Hakiki; Maryati, Yati; Aspiyanto
2017-01-01
Fermentation of Lactobacillus Acid Bacteria (LAB) which are mixtures of Lactobacillus acidophilus, Bifidobacteriumbifidum, Lactobacillus bulgaricus and Streptococcus thermophillus on hydrolysate as a result of inulin hydrolysis using inulinase enzymes obtained from endophytic fungi ofScopulariopsis sp.-CBS1 (inulin hydrolysate of S) and Class of Deuteromycetes-CBS4 (inulin hydrolysate of D) generate potential fermented inulin fiber as cholesterol binder. Fermentation process was conducted under concentrations of inulin hydrolysate 50% (w/v), LAB 15% (v/v) and skim milk 12.5% (w/v) at room temperature and 40°C for 0, 12, 24, 36 and 48 hours, respectively. Result of experimental work showed that longer time of LAB fermentation increased total acids, TPC and CBC at pH 2, but decreased total sugar, reducing, IDF, SDF, CBC pH 2 and CBC pH 7. Based on Cholesterol Binding Capacity (CBC), optimization of fermentation process on inulin hydrolysate of S was achieved by combining treatment at 40°C for 24 hours resulted in CBC pH 2 of 19.11 mg/g TDF and inulin hydrolysate of D was achieved by fermentation at 40 °C for 48 hours resulted in CBC pH 2 of 24.28 mg/g TDF. Inulin hydrolysate of class of Deutrymecetes CBS4 fermented by LAB had better functional property as cholesterol binder than that inulin hydrolysate of S fermented by LAB. This is due to cholesterol binder and cholesterol derivatives as a result of degradation of LAB on digestive system (stomach) when compared to higher colon under optimal process condition.
Tang, Meizhen; Li, Zhengtao; Yang, Yuewei; Chen, Junfeng; Jiang, Jie
2018-04-01
Constructed wetlands (CWs) have been used globally in wastewater treatment for years. CWs represent an efficient ecological system which is both energy-saving and low in investment for construction and operational cost. In addition, CWs also have the advantage of being easy to operate and maintain. However, the operation of CWs at northern latitudes (both mid and high) is sometimes quite demanding, due to the inhibitory effect of low temperatures that often occur in winter. To evaluate the wastewater treatment performance of a culture of mixed Psychrotrophic bacteria strains in an integrated vertical-flow CW, the removal rates of ammonia nitrogen (NH 3 -N), chemical oxygen demand (COD), nitrite nitrogen [Formula: see text], nitrate nitrogen [Formula: see text] and total phosphorus (TP) were quantified at different bacterial dosages to determine the best bacterial dosage and establish kinetic degradation models of the mixed strains. The bacterial culture was made up of Psychrobacter TM-1, Sphingobacterium TM-2 and Pseudomonas TM-3, mixed together at a volume/volume ratio of 1 : 1 : 1 (at bacterial suspension concentrations of 4.4 × 10 9 ml -1 ). Results showed that the organic pollutants (nitrogen and phosphorus) in the sewage could be efficiently removed by the culture of mixed Psychrotrophic bacteria. The optimal dosage of this mixed bacteria strain was 2.5%, and the treatment efficiency of COD, NH 3 -N, [Formula: see text], [Formula: see text], total nitrogen and TP were stable at 91.8%, 91.1%, 88.0%, 93.8%, 94.8% and 95.2%, respectively, which were 1.5, 2.0, 2.1, 1.5, 2.2 and 1.3 times those of the control group. In addition, a pseudo-first-order degradation model was a good fit for the degradation pattern observed for each of these pollutants.
Narbutaite, V; Fernandez, A; Horn, N; Juodeikiene, G; Narbad, A
2008-12-01
To evaluate the effect of four different baking enzymes on the inhibitory activity of five bacteriocin-like inhibitory substances (BLIS) produced by lactic acid bacteria (LAB) isolated from Lithuanian sourdoughs. The overlay assay and the Bioscreen methods revealed that the five BLIS exhibited an inhibitory effect against spore germination and vegetative outgrowth of Bacillus subtilis, the predominant species causing ropiness in bread. The possibility that the observed antibacterial activity of BLIS might be lost after treatment with enzymes used for baking purposes was also examined. The enzymes tested; hemicellulase, lipase, amyloglucosidase and amylase had little or no effect on the majority of the antimicrobial activities associated with the five BLIS studied. This study suggests a potential application in the sourdough baking industry for these antimicrobial producing LAB strains in the control of B. subtilis spore germination and vegetative outgrowth.
Lin, Xiao-Li; Pan, Qin-Jian; Tian, Hong-Gang; Douglas, Angela E; Liu, Tong-Xian
2015-03-01
Microbial abundance and diversity of different life stages (fourth instar larvae, pupae and adults) of the diamondback moth, Plutella xylostella L., collected from field and reared in laboratory, were investigated using bacteria culture-dependent method and PCR-DGGE analysis based on the sequence of bacteria 16S rRNA V3 region gene. A large quantity of bacteria was found in all life stages of P. xylostella. Field population had higher quantity of bacteria than laboratory population, and larval gut had higher quantity than pupae and adults. Culturable bacteria differed in different life stages of P. xylostella. Twenty-five different bacterial strains were identified in total, among them 20 strains were presented in larval gut, only 8 strains in pupae and 14 strains in adults were detected. Firmicutes bacteria, Bacillus sp., were the most dominant species in every life stage. 15 distinct bands were obtained from DGGE electrophoresis gel. The sequences blasted in GenBank database showed these bacteria belonged to six different genera. Phylogenetic analysis showed the sequences of the bacteria belonged to the Actinobacteri, Proteobacteria and Firmicutes. Serratia sp. in Proteobacteria was the most abundant species in larval gut. In pupae, unculturable bacteria were the most dominant species, and unculturable bacteria and Serratia sp. were the most dominant species in adults. Our study suggested that a combination of molecular and traditional culturing methods can be effectively used to analyze and to determine the diversity of gut microflora. These known bacteria may play important roles in development of P. xylostella. © 2013 Institute of Zoology, Chinese Academy of Sciences.
Zago, Miriam; Lanza, Barbara; Rossetti, Lia; Muzzalupo, Innocenzo; Carminati, Domenico; Giraffa, Giorgio
2013-05-01
Fermented table olives (Olea europaea L.) are largely diffused in the Mediterranean area. Olives are picked at different stages of maturity and after harvesting, processed to eliminate the characteristic bitterness caused by the presence of the oleuropein glucoside and to become suitable for human consumption. The spontaneous fermentation of table olives mainly depends on lactic acid bacteria (LAB), and in particular on Lactobacillus plantarum which plays an important role in the degradation of oleuropein. The hydrolysis of oleuropein is attributed to the β-glucosidase and esterase activities of the indigenous LAB microflora. This study investigated the potential of L. plantarum strains isolated from dairy products and olives to be used as starters for fermented table olives. Forty-nine strains were typed by RAPD-PCR and investigated for the presence of the β-glucosidase (bglH) gene. The full sequence of the bglH gene was carried out. All the 49 L. plantarum strains were also tested for phage resistance. A total of six strains were selected on the basis of genotypic polymorphism, bglH gene sequence analysis, and phage resistance profile. These strains were further characterized to assess the acidifying capability, the growth at different temperatures, the tolerance to different NaCl concentrations, and the oleuropeinolytic activity. Although further characterizations are required, especially concerning the influence on sensory properties, L. plantarum proved to have the potential to be used as a debittering and fermentative agent in starter culture for fermented table olives. Copyright © 2012 Elsevier Ltd. All rights reserved.
Settanni, L; Di Grigoli, A; Tornambé, G; Bellina, V; Francesca, N; Moschetti, G; Bonanno, A
2012-04-02
The present work was undertaken to evaluate the influence of the wooden dairy plant equipment on the microbiological characteristics of curd to be transformed into Caciocavallo Palermitano cheese. Traditional raw milk productions were performed concomitantly with standard cheese making trials carried out in stainless steel vat inoculated with a commercial starter. Milk from two different farms (A and B) was separately processed. The wooden vat was found to be a reservoir of lactic acid bacteria (LAB), while unwanted (spoilage and/or pathogenic) microorganisms were not hosted or were present at very low levels. All microbial groups were numerically different in bulk milks, showing higher levels for the farm B. LAB, especially thermophilic cocci, dominated the whole cheese making process of all productions. Undesired microorganisms decreased in number or disappeared during transformation, particularly after curd stretching. LAB were isolated from the wooden vat surface and from all dairy samples, subjected to phenotypic and genetic characterization and identification. Streptococcus thermophilus was the species found at the highest concentration in all samples analyzed and it also dominated the microbial community of the wooden vat. Fourteen other LAB species belonging to six genera (Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Streptococcus and Weissella) were also detected. All S. thermophilus isolates were genetically differentiated and a consortium of four strains persisted during the whole traditional production process. As confirmed by pH and the total acidity after the acidification step, indigenous S. thermophilus strains acted as a mixed starter culture. Copyright © 2012 Elsevier B.V. All rights reserved.
Lab Simulates Outdoor Algae Growth
DOE Office of Scientific and Technical Information (OSTI.GOV)
None
Algae can be turned into renewable biofuel, which is why scientists want to discover an inexpensive, fast-growing strain of algae. Scientists at Pacific Northwest National Laboratory have developed a system to speed up this search. The unique climate-simulating system uses temperature controls and multi-colored LED lights to mimic the constantly changing conditions of an outdoor algae pond. By simulating outdoor climates inside the lab, the system saves researchers time and expense.
SHIMADA, Ayumi; NODA, Masafumi; MATOBA, Yasuyuki; KUMAGAI, Takanori; KOZAI, Katsuyuki; SUGIYAMA, Masanori
2015-01-01
Previous studies have demonstrated that the presence of lactic acid bacteria (LAB), especially those classified into the genus Lactobacillus, is associated with the progression of dental caries in preschool children. Nevertheless, the kinds of species of LAB and the characteristics that are important for dental caries have been unclear. The aims of this study were: (1) to investigate the distribution of oral LAB among Japanese preschool children with various prevalence levels of caries; and (2) to reveal the characteristics of these isolated LAB species. Seventy-four Japanese preschool children were examined for caries scores and caries progression, and their dental cavity samples were collected for LAB isolation and identification. The saliva-induced agglutination rate and the resistance to acidic environments of the identified strains were measured. Statistical analysis showed that preschool children carrying Lactobacillus (L.) salivarius or Streptococcus mutans have a significantly higher prevalence of dental caries, the growth ability in acidic environments correlates with the caries scores of individuals with L. salivarius, and the caries scores exhibit positive correlation with saliva-induced agglutination in L. salivarius. These results show that specific Lactobacillus species are associated with dental caries based on the level of carious lesion severity. The present study suggests that these specific Lactobacillus species, especially those with easily agglutinated properties and acid resistance, affect the dental caries scores of preschool children, and that these properties may provide useful information for research into the prevention of dental caries. PMID:25918670
Shimada, Ayumi; Noda, Masafumi; Matoba, Yasuyuki; Kumagai, Takanori; Kozai, Katsuyuki; Sugiyama, Masanori
2015-01-01
Previous studies have demonstrated that the presence of lactic acid bacteria (LAB), especially those classified into the genus Lactobacillus, is associated with the progression of dental caries in preschool children. Nevertheless, the kinds of species of LAB and the characteristics that are important for dental caries have been unclear. The aims of this study were: (1) to investigate the distribution of oral LAB among Japanese preschool children with various prevalence levels of caries; and (2) to reveal the characteristics of these isolated LAB species. Seventy-four Japanese preschool children were examined for caries scores and caries progression, and their dental cavity samples were collected for LAB isolation and identification. The saliva-induced agglutination rate and the resistance to acidic environments of the identified strains were measured. Statistical analysis showed that preschool children carrying Lactobacillus (L.) salivarius or Streptococcus mutans have a significantly higher prevalence of dental caries, the growth ability in acidic environments correlates with the caries scores of individuals with L. salivarius, and the caries scores exhibit positive correlation with saliva-induced agglutination in L. salivarius. These results show that specific Lactobacillus species are associated with dental caries based on the level of carious lesion severity. The present study suggests that these specific Lactobacillus species, especially those with easily agglutinated properties and acid resistance, affect the dental caries scores of preschool children, and that these properties may provide useful information for research into the prevention of dental caries.
Functional Properties of Lactobacillus mucosae Strains Isolated from Brazilian Goat Milk.
de Moraes, Georgia Maciel Dias; de Abreu, Louricélia Rodrigues; do Egito, Antônio Silvio; Salles, Hévila Oliveira; da Silva, Liana Maria Ferreira; Nero, Luís Augusto; Todorov, Svetoslav Dimitrov; Dos Santos, Karina Maria Olbrich
2017-09-01
The search for probiotic candidates among lactic acid bacteria (LAB) isolated from food may uncover new strains with promising health and technological properties. Lactobacillus mucosae strains attracted recent research attention due to their ability to adhere to intestinal mucus and to inhibit pathogens in the gastrointestinal tract, both related to a probiotic potential. Properties of interest and safety aspects of three Lb. mucosae strains (CNPC006, CNPC007, and CNPC009) isolated from goat milk were investigated employing in vitro tests. The presence of genetic factors related to bile salt hydrolase production (bsh), intestinal adhesion properties (msa, map, mub, and ef-tu), virulence, and biogenic amine production were also verified. All strains exhibited the target map, mub, and ef-tu sequences; the msa gene was detected in CNPC006 and CNPC007 strains. Some of the searched sequences for virulence factors were detected, especially in the CNPC009 strain; all strains carried the hyl gene, related to the production of hyaluronidase. Lb. mucosae CNPC007 exhibited a high survival rate in simulated gastric and enteric conditions. Besides, all strains exhibited the bsh sequence, and CNPC006 and CNPC007 were able to deconjugate salts of glycodeoxycholic acid (GDC). Regarding technological properties for dairy product applications, a relatively higher milk acidification and clotting capacity, diacetyl production, and proteolytic activity were registered for CNPC007 in comparison to the other strains. Collectively, the results aim at Lb. mucosae CNPC007 as a promising probiotic candidate for application in dairy products, deserving further studies to confirm and explore its potential.
Antagonism of Lactic Acid Bacteria against Phytopathogenic Bacteria
Visser, Ronèl; Holzapfel, Wilhelm H.; Bezuidenhout, Johannes J.; Kotzé, Johannes M.
1986-01-01
A variety of lactic acid bacteria, isolated from plant surfaces and plant-associated products, were found to be antagonistic to test strains of the phytopathogens Xanthomonas campestris, Erwinia carotovora, and Pseudomonas syringae. Effective “in vitro” inhibition was found both on agar plates and in broth cultures. In pot trials, treatment of bean plants with a Lactobacillus plantarum strain before inoculation with P. syringae caused a significant reduction of the disease incidence. Images PMID:16347150
Polysaccharide production by lactic acid bacteria: from genes to industrial applications.
Zeidan, Ahmad A; Poulsen, Vera Kuzina; Janzen, Thomas; Buldo, Patrizia; Derkx, Patrick M F; Øregaard, Gunnar; Neves, Ana Rute
2017-08-01
The ability to produce polysaccharides with diverse biological functions is widespread in bacteria. In lactic acid bacteria (LAB), production of polysaccharides has long been associated with the technological, functional and health-promoting benefits of these microorganisms. In particular, the capsular polysaccharides and exopolysaccharides have been implicated in modulation of the rheological properties of fermented products. For this reason, screening and selection of exocellular polysaccharide-producing LAB has been extensively carried out by academia and industry. To further exploit the ability of LAB to produce polysaccharides, an in-depth understanding of their biochemistry, genetics, biosynthetic pathways, regulation and structure-function relationships is mandatory. Here, we provide a critical overview of the latest advances in the field of glycosciences in LAB. Surprisingly, the understanding of the molecular processes involved in polysaccharide synthesis is lagging behind, and has not accompanied the increasing commercial value and application potential of these polymers. Seizing the natural diversity of polysaccharides for exciting new applications will require a concerted effort encompassing in-depth physiological characterization of LAB at the systems level. Combining high-throughput experimentation with computational approaches, biochemical and structural characterization of the polysaccharides and understanding of the structure-function-application relationships is essential to achieve this ambitious goal. © FEMS 2017.
Ayala, D I; Chen, J C; Bugarel, M; Loneragan, G H; den Bakker, H C; Kottapalli, K R; Brashears, M M; Nightingale, K K
2018-04-17
Lactobacillus animalis NP51 is a direct-fed microbial strain (DFM) extensively used as a pre-harvest food safety mitigation in feedlot cattle due to its antagonistic effects against human foodborne pathogens such as Salmonella and Escherichia coli O157:H7. NP51 not only promotes overall gut health but interferes with the ability of these pathogens to colonize the gastrointestinal tract of cattle. As a result, NP51 reduces fecal shedding of Salmonella and E. coli O157:H7 in cattle presented for harvest and the load of these pathogens that enter the human food chain. Cattle are administered a high dose (1 × 10 9 CFU/head/day) of NP51 to reduce fecal shedding of foodborne pathogens. Ensiled animal feedstuffs naturally contain a high load of lactic acid bacteria (LAB) and it is not possible to detect and quantify the level of a specific LAB strain (e.g., NP51) in this matrix using traditional microbiological culture. The purpose of this study was to develop a molecular method to detect and quantify viable populations of a specific LAB strain (e.g., NP51) in cattle feedstuffs. The NP51 whole genome sequence was aligned with closely related LAB clustering within the same well-supported clade in a LAB phylogeny derived from 30 conserved amino acid encoding sequence to identify orthologs. A sequence encoding recombinational DNA repair protein RecT was found to be unique to NP51 and used to design primers and a probe for molecular detection and quantification of NP51. The primers and probe were confirmed to be specific to NP51 in vitro. Total RNA was extracted from silage samples, including samples naturally inoculated in the field and control samples that were artificially spiked with a range of NP51 concentrations in the laboratory. Reverse-transcriptase quantitative real-time (RT-qRTi) PCR was used to quantify cDNA copies in samples and cycle threshold (Ct) values were compared to a standard curve to estimate NP51 concentrations. Our results indicate this novel
Pothakos, Vasileios; Samapundo, Simbarashe; Devlieghere, Frank
2012-12-01
The major objective of this study was to determine the role of psychrotrophic lactic acid bacteria (LAB) in spoilage-associated phenomena at the end of the shelf-life of 86 various packaged (air, vacuum, modified-atmosphere) chilled-stored retail food products. The current microbiological standards, which are largely based on the total viable mesophilic counts lack discriminatory capacity to detect psychrotrophic LAB. A comparison between the total viable counts on plates incubated at 30 °C (representing the mesophiles) and at 22 °C (indicating the psychrotrophs) for 86 food samples covering a wide range - ready-to-eat vegetable salads, fresh raw meat, cooked meat products and composite food - showed that a consistent underestimation of the microbial load occurs when the total aerobic mesophilic counts are used as a shelf-life parameter. In 38% of the samples, the psychrotrophic counts had significantly higher values (+0.5-3 log CFU/g) than the corresponding total aerobic mesophilic counts. A total of 154 lactic acid bacteria, which were unable to proliferate at 30 °C were isolated. In addition, a further 43 with a poor recovery at this temperature were also isolated. This study highlights the potential fallacy of the total aerobic mesophilic count as a reference shelf-life parameter for chilled food products as it can often underestimate the contamination levels at the end of the shelf-life. Copyright © 2012 Elsevier Ltd. All rights reserved.
Ho, Van Thi Thuy; Fleet, Graham H; Zhao, Jian
2018-08-20
Cocoa beans (Theobroma cacao L.) are the raw material for chocolate production. Fermentation of the bean pulp by microorganisms is essential for developing the precursors of chocolate flavour. Currently, the cocoa fermentation is still conducted by an uncontrolled traditional process via a consortium of indigenous species of yeasts, lactic acid bacteria and acetic acid bacteria. Although the essential contribution of yeasts to the production of good quality beans and, typical chocolate character is generally agreed, the roles of lactic acid bacteria and acetic acid bacteria are less certain. The objective of this study was to investigate the contribution of LAB and AAB in cocoa bean fermentation by conducting small scale laboratory fermentations under aseptic conditions, inoculated with different groups of microorganisms previously isolated from spontaneous cocoa fermentations. The inoculation protocols were: (1) four yeasts Hanseniaspora guilliermondii, Pichia kudriavzevii, Kluyveromyces marxianus and Saccharomyces cerevisiae; (2) four yeasts plus the lactic acid bacteria Lactobacillus plantarum and Lactobacillus fermentum; (3) four yeasts plus the acetic acid bacteria Acetobacter pasteurianus and Gluconobacter frateuri and (4) four yeasts plus two lactic acid bacteria and two acetic acid bacteria. Only the inoculated species were detected in the microbiota of their respective fermentations. Beans from the inoculated fermentations showed no significant differences in colour, shell weights and concentrations of residual sugars, alcohols and esters (p>0.05), but they were slightly different in contents of lactic acid and acetic acid (p<0.05). All beans were fully brown and free of mould. Residual sugar levels were less than 2.6 mg/g while the shell contents and ethanol were in the range of 11-13.4% and 4.8-7 mg/g, respectively. Beans fermented in the presence of LAB contained higher levels of lactic acid (0.6-1.2 mg/g) whereas higher concentrations of acetic acid
Palla, Michela; Cristani, Caterina; Giovannetti, Manuela; Agnolucci, Monica
2017-06-05
Sourdough fermentation has been increasingly used worldwide, in accordance with the demand of consumers for tasty, natural and healthy food. The high diversity of lactic acid bacteria (LAB) and yeast species, detected in sourdoughs all over the world, may affect nutritional, organoleptic and technological traits of leavened baked goods. A wide regional variety of traditional sourdough breads, over 200 types, has been recorded in Italy, including special types selected as worthy of either Protected Geographical Indication (PGI) or Protected Designation of Origin (PDO), whose sourdough microbiota has been functionally and molecularly characterized. As, due to the very recent designation, the microbiota of Tuscan bread sourdough has not been investigated so far, the aim of the present work was to isolate and characterize the species composition of LAB and yeasts of PDO Tuscan bread sourdough by culture-independent and dependent methods. A total of 130 yeasts from WLN medium and 193 LAB from both mMRS and SDB media were isolated and maintained to constitute the germplasm bank of PDO Tuscan bread. Ninety six LAB from mMRS medium and 68 yeasts from WLN medium were randomly selected and molecularly identified by ARDRA (Amplified Ribosomal DNA Restriction Analysis) and PCR-RFLP analysis of the ITS region, respectively, and sequencing. The yeast identity was confirmed by 26S D1/D2 sequencing. All bacterial isolates showed 99% identity with Lactobacillus sanfranciscensis, 65 yeast isolates were identified as Candida milleri, and 3 as Saccharomyces cerevisiae. Molecular characterization of PDO Tuscan bread sourdough by PCR-DGGE confirmed such data. The distinctive tripartite species association, detected as the microbiota characterizing the sourdough used to produce PDO Tuscan bread, encompassed a large number of L. sanfranciscensis and C. milleri strains, along with a few of S. cerevisiae. The relative composition and specific physiological characteristics of such microbiota
Biotechnological and in situ food production of polyols by lactic acid bacteria.
Ortiz, Maria Eugenia; Bleckwedel, Juliana; Raya, Raúl R; Mozzi, Fernanda
2013-06-01
Polyols such as mannitol, erythritol, sorbitol, and xylitol are naturally found in fruits and vegetables and are produced by certain bacteria, fungi, yeasts, and algae. These sugar alcohols are widely used in food and pharmaceutical industries and in medicine because of their interesting physicochemical properties. In the food industry, polyols are employed as natural sweeteners applicable in light and diabetic food products. In the last decade, biotechnological production of polyols by lactic acid bacteria (LAB) has been investigated as an alternative to their current industrial production. While heterofermentative LAB may naturally produce mannitol and erythritol under certain culture conditions, sorbitol and xylitol have been only synthesized through metabolic engineering processes. This review deals with the spontaneous formation of mannitol and erythritol in fermented foods and their biotechnological production by heterofermentative LAB and briefly presented the metabolic engineering processes applied for polyol formation.
Activity and cellular localization of amylases of rabbit cecal bacteria.
Sirotek, K; Marounek, M; Suchorská, O
2006-01-01
Five 11-week-old rabbits, fed a commercial granulated feed, were slaughtered and cecal starch-degrading bacteria enumerated; total concentration of cultivable bacteria utilizing starch averaged 5.5 x 10(10) CFU/g. The activity and cellular localization of amylases was determined in 9 bacteria identified as Actinomyces israeli (strains AA2 and AD4), Bacteroides spp. (strain AA3), Dichelobacter nodosus (strain AA4), Mitsuokella multiacidus (strain AA6), Eubacterium spp. (strains AA7 and AB2), Clostridium spp. (strains AD1 and AA5). Four strains (AA3, AA4, AA5, AD4) produced extracellular amylases with an activity of 26-35 micromol of reducing sugars per h per mg of protein; in five strains (AA2, AA6, AA7, AB2, AD1) amylases were membrane-bound with an activity of 14-18 micromol of reducing sugars per h per mg of protein. All strains exhibited a low intracellular amylolytic activity. The pH optimum of amylases was 6.8-7.0. In strains producing extracellular amylases a substantial loss of viscosity was observed during incubations of cultivation supernatant with starch, similar to viscosity reduction in starch solutions treated with alpha-amylase; this indicates an endo-type (random cleavage) of extracellular amylase reaction in the bacteria under study. No strain possessed glucoamylase activity.
[Lactic acid bacteria proteinase and quality of fermented dairy products--A review].
Zhang, Shuang; Zhang, Lanwei; Han, Xue
2015-12-04
Lactic acid bacteria (LAB) could synthesize cell envelope proteinase with weak activity, which primarily degrades casein. In addition to its crucial role in the rapid growth of LAB in milk, LAB proteinases are also of industrial importance due to their contribution to the formation of texture and flavor of many fermented dairy products. The proteolytic system, properties of proteinase, the degradation product of casein and its effect on the quality of fermented dairy products were reviewed in this manuscript.
NASA Astrophysics Data System (ADS)
Putra, T. F.; Suprapto, H.; Tjahjaningsih, W.; Pramono, H.
2018-04-01
Peda is an Indonesian traditional fermented whole fish prepared by addition of salt prior to fermentation and drying process. Salt used to control the growth of the lactic acid bacteria for the fermentation process. The objectives of this study were isolating and characterize the potential lactic acid bacteria (LAB) from peda as culture starter candidate, particularly its activity against pathogenic bacteria. A total of five samples from five regions of East Java Province was collected and subjected to LAB isolation. Fifty-seven of 108 colonies that show clear zone in de Man, Rogosa and Sharpe (MRS) agar supplemented with 0.5% CaCO3 were identified as LAB. Twenty-seven of the LAB isolates were exhibit inhibition against Staphylococcus aureus ATCC 6538 and Pseudomonas aeruginosa ATCC 27853. Isolate Aerococcus NJ-20 was exhibited strong inhibition against S. aureus ATCC 6538 (7.6 ± 1.35 mm inhibition zone) but was not produce bacteriocin. This finding suggests that the isolate Aerococcus NJ-20 can be applied as biopreservative culture starter on peda production. Further analysis on technological properties of isolates will be needed prior to application.
Stets, Maria Isabel; Alqueres, Sylvia Maria Campbell; Souza, Emanuel Maltempi; Pedrosa, Fábio de Oliveira; Schmid, Michael; Hartmann, Anton; Cruz, Leonardo Magalhães
2015-10-01
Azospirillum is a rhizobacterial genus containing plant growth-promoting species associated with different crops worldwide. Azospirillum brasilense strains exhibit a growth-promoting effect by means of phytohormone production and possibly by N2 fixation. However, one of the most important factors for achieving an increase in crop yield by plant growth-promoting rhizobacteria is the survival of the inoculant in the rhizosphere, which is not always achieved. The objective of this study was to develop quantitative PCR protocols for the strain-specific quantification of A. brasilense FP2. A novel approach was applied to identify strain-specific DNA sequences based on a comparison of the genomic sequences within the same species. The draft genome sequences of A. brasilense FP2 and Sp245 were aligned, and FP2-specific regions were filtered and checked for other possible matches in public databases. Strain-specific regions were then selected to design and evaluate strain-specific primer pairs. The primer pairs AzoR2.1, AzoR2.2, AzoR5.1, AzoR5.2, and AzoR5.3 were specific for the A. brasilense FP2 strain. These primer pairs were used to monitor quantitatively the population of A. brasilense in wheat roots under sterile and nonsterile growth conditions. In addition, coinoculations with other plant growth-promoting bacteria in wheat were performed under nonsterile conditions. The results showed that A. brasilense FP2 inoculated into wheat roots is highly competitive and achieves high cell numbers (∼10(7) CFU/g [fresh weight] of root) in the rhizosphere even under nonsterile conditions and when coinoculated with other rhizobacteria, maintaining the population at rather stable levels for at least up to 13 days after inoculation. The strategy used here can be applied to other organisms whose genome sequences are available. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
Stets, Maria Isabel; Alqueres, Sylvia Maria Campbell; Souza, Emanuel Maltempi; Pedrosa, Fábio de Oliveira; Schmid, Michael
2015-01-01
Azospirillum is a rhizobacterial genus containing plant growth-promoting species associated with different crops worldwide. Azospirillum brasilense strains exhibit a growth-promoting effect by means of phytohormone production and possibly by N2 fixation. However, one of the most important factors for achieving an increase in crop yield by plant growth-promoting rhizobacteria is the survival of the inoculant in the rhizosphere, which is not always achieved. The objective of this study was to develop quantitative PCR protocols for the strain-specific quantification of A. brasilense FP2. A novel approach was applied to identify strain-specific DNA sequences based on a comparison of the genomic sequences within the same species. The draft genome sequences of A. brasilense FP2 and Sp245 were aligned, and FP2-specific regions were filtered and checked for other possible matches in public databases. Strain-specific regions were then selected to design and evaluate strain-specific primer pairs. The primer pairs AzoR2.1, AzoR2.2, AzoR5.1, AzoR5.2, and AzoR5.3 were specific for the A. brasilense FP2 strain. These primer pairs were used to monitor quantitatively the population of A. brasilense in wheat roots under sterile and nonsterile growth conditions. In addition, coinoculations with other plant growth-promoting bacteria in wheat were performed under nonsterile conditions. The results showed that A. brasilense FP2 inoculated into wheat roots is highly competitive and achieves high cell numbers (∼107 CFU/g [fresh weight] of root) in the rhizosphere even under nonsterile conditions and when coinoculated with other rhizobacteria, maintaining the population at rather stable levels for at least up to 13 days after inoculation. The strategy used here can be applied to other organisms whose genome sequences are available. PMID:26187960
Ouattara, Hadja D; Ouattara, Honoré G; Droux, Michel; Reverchon, Sylvie; Nasser, William; Niamke, Sébastien L
2017-09-01
Microbial fermentation is an indispensable process for high quality chocolate from cocoa bean raw material. lactic acid bacteria (LAB) are among the major microorganisms responsible for cocoa fermentation but their exact role remains to be elucidated. In this study, we analyzed the diversity of LAB in six cocoa producing regions of Ivory Coast. Ribosomal 16S gene sequence analysis showed that Lactobacillus plantarum and Leuconostoc mesenteroides are the dominant LAB species in these six regions. In addition, other species were identified as the minor microbial population, namely Lactobacillus curieae, Enterococcus faecium, Fructobacillus pseudoficulneus, Lactobacillus casei, Weissella paramesenteroides and Weissella cibaria. However, in each region, the LAB microbial population was composed of a restricted number of species (maximum 5 species), which varied between the different regions. LAB implication in the breakdown of citric acid was investigated as a fundamental property for a successful cocoa fermentation process. High citrate lyase producer strains were characterized by rapid citric acid consumption, as revealed by a 4-fold decrease in citric acid concentration in the growth medium within 12h, concomitant with an increase in acetic acid and lactic acid concentration. The production of citrate lyase was strongly dependent on environmental conditions, with optimum production at acidic pH (pH<5), and moderate temperature (30-40°C), which corresponds to conditions prevailing in the early stage of natural cocoa fermentation. This study reveals that one of the major roles of LAB in the cocoa fermentation process involves the breakdown of citric acid during the early stage of cocoa fermentation through the activity of citrate lyase. Copyright © 2017 Elsevier B.V. All rights reserved.
Orihuel, Alejandra; Terán, Lucrecia; Renaut, Jenny; Vignolo, Graciela M; De Almeida, André M; Saavedra, María L; Fadda, Silvina
2018-01-01
Human infection by Enterohemorrhagic Escherichia (E.) coli (EHEC) occurs through the ingestion of contaminated foods such as milk, vegetable products, water-based drinks, and particularly minced meats. Indeed EHEC is a pathogen that threatens public health and meat industry. The potential of different Lactic Acid Bacteria (LAB) strains to control EHEC in a meat-based medium was evaluated by using a simple and rapid method and by analyzing the growth kinetics of co-cultures (LAB-EHEC) in a meat-based medium. The activity of LAB toward EHEC in co-cultures showed variable inhibitory effect. Although, LAB were able to control EHEC, neither the produced acid nor bacteriocins were responsible of the inhibition. The bacteriocinogenic Enteroccus (Ent.) mundtii CRL35 presented one of the highest inhibition activities. A proteomic approach was used to evaluate bacterial interaction and antagonistic mechanisms between Ent. mundtii and EHEC. Physiological observations, such as growth kinetics, acidification ability and EHEC inhibitory potential were supported by the proteomic results, demonstrating significant differences in protein expression in LAB: (i) due to the presence of the pathogen and (ii) according to the growth phase analyzed. Most of the identified proteins belonged to carbohydrate/amino acid metabolism, energy production, transcription/translation, and cell division. These results contribute to the knowledge of competition strategies used by Ent. mundtii during its co-culture with EHEC setting new perspectives for the use of LAB to control this pathogen in meat.
Primary souring: A novel bacteria-free method for sour beer production.
Osburn, Kara; Amaral, Justin; Metcalf, Sara R; Nickens, David M; Rogers, Cody M; Sausen, Christopher; Caputo, Robert; Miller, Justin; Li, Hongde; Tennessen, Jason M; Bochman, Matthew L
2018-04-01
In the beverage fermentation industry, especially at the craft or micro level, there is a movement to incorporate as many local ingredients as possible to both capture terroir and stimulate local economies. In the case of craft beer, this has traditionally only encompassed locally sourced barley, hops, and other agricultural adjuncts. The identification and use of novel yeasts in brewing lags behind. We sought to bridge this gap by bio-prospecting for wild yeasts, with a focus on the American Midwest. We isolated 284 different strains from 54 species of yeast and have begun to determine their fermentation characteristics. During this work, we found several isolates of five species that produce lactic acid and ethanol during wort fermentation: Hanseniaspora vineae, Lachancea fermentati, Lachancea thermotolerans, Schizosaccharomyces japonicus, and Wickerhamomyces anomalus. Tested representatives of these species yielded excellent attenuation, lactic acid production, and sensory characteristics, positioning them as viable alternatives to lactic acid bacteria (LAB) for the production of sour beers. Indeed, we suggest a new LAB-free paradigm for sour beer production that we term "primary souring" because the lactic acid production and resultant pH decrease occurs during primary fermentation, as opposed to kettle souring or souring via mixed culture fermentation. Copyright © 2017 Elsevier Ltd. All rights reserved.
Rodriguez, A V; Baigorí, M D; Alvarez, S; Castro, G R; Oliver, G
2001-10-16
Phosphatidylinositol-specific phospholipase C (PI-PLC) activity was investigated in 25 different lactic acid bacteria (LAB) strains belonging to the genera Lactobacillus, Weisella, and Enterococcus. PI-PLC activity was detected in 44% of the strains studied in culture medium without carbon source. From the PI-PLC positive strains, Lactobacillus rhamnosus ATCC 7469 was selected for translocation studies. Healthy mice were orally administered with a daily dose of 2.0 x 10(9) of viable L. rhamnosus suspension. Viable bacteria were detected in liver and spleen of mice fed with LAB for 7 days. Bacterial colonies isolated from liver were biochemically characterized, and further subjected to randomly amplified polymorphic DNA. Amplification patterns of five strains displayed identical profiles to L. rhamnosus. PI-PLC activity was determined in the strains recovered from liver.
Screening of antagonistic bacteria isolated from Amorphophallus konjac rhizosphere soil
NASA Astrophysics Data System (ADS)
Lin, Tianxing; Gong, Mingfu; Guan, Qinlan; Huang, Ying; Qin, Fang
2018-04-01
Bacteria lived in Amorphaphallus konjac rhizosphere soil have the potential ability of antagonistic bacterial pathogen activity against to Erwinia carotovora subsp carotovora (Ecc). The paper was to study and analyze all strains of 18 bacteria isolated from A. konjac rhizosphere soil with strong antagonistic effect against to Ecc and to identify antagonistic bacteria with morphology, physiology and biochemistry characteristic. The antagonistic bacterial pathogen activity of different bacterial strains were significantly different. Five of 18 strains isolated from A. konjac rhizosphere soil, including AKSB03, AKSB05, AKSB08, AKSB13 and AKSB16 was screened with antagonistic wider more than 15 mm in first screening test. Strain AKSB08 and strain AKSB16 had a strong antagonism activity for Ecc with antagonistic wider more than 20 mm in second screening test. Strain AKSB08 and strain AKSB16 belonged to Bacillus with morphology, physiology and biochemistry characteristic.
Chaikaew, Siriporn; Baipong, Sasitorn; Sone, Teruo; Kanpiengjai, Apinun; Chui-Chai, Naradorn; Asano, Kozo; Khanongnuch, Chartchai
2017-09-01
The microbiota of lactic acid bacteria (LAB) in thirty-five samples of Miang, a traditional fermented tea leaf product, collected from twenty-two different regions of eight provinces in upper northern Thailand was revealed through the culture-dependent technique. A total of 311 presumptive LAB strains were isolated and subjected to clustering analysis based on repetitive genomic element-PCR (rep-PCR) fingerprinting profiles. The majority of the strains belonged to the Lactobacillus genera with an overwhelming predominance of the Lb. plantarum group. Further studies of species-specific PCR showed that 201 of 252 isolates in the Lb. plantarum group were Lb. plantarum which were thus considered as the predominant LAB in Miang, while the other 51 isolates belonged to Lb. pentosus. In contrast to Lb. plantarum, there is a lack of information on the tannase gene and the tea tannin-tolerant ability of Lb. pentosus. Of the 51 Lb. pentosus isolates, 33 were found to harbor the genes encoding tannase and shared 93-99% amino acid identity with tannase obtained from Lb. pentosus ATCC 8041 T . Among 33 tannase gene-positive isolates, 23 isolates exhibited high tannin- tolerant capabilities when cultivated on de Man Rogosa and Sharpe agar-containing bromocresol purple (0.02 g/L, MRS-BCP) supplemented with 20% (v/v) crude tea extract, which corresponded to 2.5% (w/v) tannins. These Lb. pentosus isolates with high tannin-tolerant capacity are expected to be the high potential strains for functional tannase production involved in Miang fermentation as they will bring about certain benefits and could be used to improve the fermentation of tea products.
Biodegradation of Mixed PAHs by PAH-Degrading Endophytic Bacteria.
Zhu, Xuezhu; Ni, Xue; Waigi, Michael Gatheru; Liu, Juan; Sun, Kai; Gao, Yanzheng
2016-08-09
Endophytic bacteria can promote plant growth, induce plant defence mechanisms, and increase plant resistance to organic contaminants. The aims of the present study were to isolate highly PAH-degrading endophytic bacteria from plants growing at PAH-contaminated sites and to evaluate the capabilities of these bacteria to degrade polycyclic aromatic hydrocarbons (PAHs) in vitro, which will be beneficial for re-colonizing target plants and reducing plant PAH residues through the inoculation of plants with endophytic bacteria. Two endophytic bacterial strains P₁ (Stenotrophomonas sp.) and P₃ (Pseudomonas sp.), which degraded more than 90% of phenanthrene (PHE) within 7 days, were isolated from Conyza canadensis and Trifolium pretense L., respectively. Both strains could use naphthalene (NAP), PHE, fluorene (FLR), pyrene (PYR), and benzo(a)pyrene (B(a)P) as the sole sources of carbon and energy. Moreover, these bacteria reduced the contamination of mixed PAHs at high levels after inoculation for 7 days; strain P₁ degraded 98.0% NAP, 83.1% FLR, 87.8% PHE, 14.4% PYR, and 1.6% B(a)P, and strain P₃ degraded 95.3% NAP, 87.9% FLR, 90.4% PHE, 6.9% PYR, and negligible B(a)P. Notably, the biodegradation of PAHs could be promoted through additional carbon and nitrogen nutrients; therein, beef extract was suggested as the optimal co-substrate for the degradation of PAHs by these two strains (99.1% PHE was degraded within 7 days). Compared with strain P₁, strain P₃ has more potential for the use in the removal of PAHs from plant tissues. These results provide a novel perspective in the reduction of plant PAH residues in PAH-contaminated sites through inoculating plants with highly PAH-degrading endophytic bacteria.
Bio-transformation of selenium in Se-enriched bacterial strains of Lactobacillus casei.
Kurek, Eliza; Ruszczyńska, Anna; Wojciechowski, Marcin; Łuciuk, Anna; Michalska-Kacymirow, Magdalena; Motyl, Ilona; Bulska, Ewa
Selenium is an element of very great importance for the proper functioning of the human body, mainly due to its antioxidant properties. Selenium exhibits a preventive effect in the case of cardiovascular disease, the immune system, male infertility and inhibits the toxic action of other agents. Selenium is important for Hashimoto's disease. Intake of selenium in the diet slows the aging process. The biological and toxicological effects of selenium strongly depend on its chemical form. Some organisms for example: plant, yeast, are capable of metabolizing low bioavailable selenium compounds (inorganic selenium) into its high bioavailable forms (organic selenium). The aim of this study was to investigate the bio-transformation of selenium by Lactobacillus bacteria towards the characterisation of selenium metabolites. The speciation of selenium was evaluated by high performance liquid chromatography with inductively coupled plasma mass spectrometry detector. The extraction of selenium species from lyophilized bacteria was executed with water, the mixture of lipase and protease, as well as lisozyme and sodium dodecyl sulphate. All investigated bacteria strains cultivated in the presence of Na2SeO3 effectively uptake selenium. Surprisingly, none of the applied extraction media exhibited a strong power to release the majority of the uptaken selenium compounds. Thus a maximum of 10% of the selenium was extracted from bacteria exposed to the enzymes. However, it was found that Lactobacillus bacteria are able to metabolize inorganic ions of selenium (IV) into Se-methionine, Se-methyloselenocysteine and other unidentified forms. The study confirmed the ability of probiotic bacteria to biotransform inorganic selenium into its organic derivatives. Therefore, Se-enriched bacteria can be considered as an addition to the functional food. selenium speciation, extraction procedure, Lactobacillus casei bacteria, Lactic acid bacteria (LAB), HPLC ICP-MS, functional food.
de Llano, Dolores González; Arroyo, Amalia; Cárdenas, Nivia; Rodríguez, Juan Miguel; Moreno-Arribas, M Victoria; Bartolomé, Begoña
2017-06-01
Urinary tract infections (UTIs), one of most common infections worldwide, face high recurrence rates and increasing antimicrobial resistance. Probiotic bacteria, especially of the genus Lactobacillus, are considered a promising preventive and/or treatment therapy against UTIs. In order to elucidate the mechanisms involved in these beneficial effects, we studied the impact of different Lactobacillus strains (Lactobacillus salivarius UCM572, L. plantarum CLC17 and L. acidophilus 01) in the adherence of reference and clinical uropathogenic strains (Escherichia coli ATCC® 53503, E. coli 10791, Enterococcus faecalis 04-1, En. faecalis 08-1 and Staphylococcus epidermidis 08-3) to T24 epithelial bladder cells. In general, the Lactobacillus strains with previous in vivo evidence of beneficial effects against UTIs (L. salivarius UCM572 and L. acidophilus 01) significantly inhibited the adherence of the five uropathogens to T24 cells, displaying percentages of inhibition ranging between 22.2% and 43.9%, and between 16.5% and 53.7%, respectively. On the other hand, L. plantarum CLC17, a strain with no expected effects on UTIs, showed almost negligible anti-adherence effects.Therefore, these in vitro results suggest that inhibition of the adherence of uropathogens to epithelial bladder cells may be one of the mechanisms involved in the potential beneficial effects of probiotics against UTIs in vivo. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Gaspar, Paula; Carvalho, Ana L; Vinga, Susana; Santos, Helena; Neves, Ana Rute
2013-11-01
The lactic acid bacteria (LAB) are a functionally related group of low-GC Gram-positive bacteria known essentially for their roles in bioprocessing of foods and animal feeds. Due to extensive industrial use and enormous economical value, LAB have been intensively studied and a large body of comprehensive data on their metabolism and genetics was generated throughout the years. This knowledge has been instrumental in the implementation of successful applications in the food industry, such as the selection of robust starter cultures with desired phenotypic traits. The advent of genomics, functional genomics and high-throughput experimentation combined with powerful computational tools currently allows for a systems level understanding of these food industry workhorses. The technological developments in the last decade have provided the foundation for the use of LAB in applications beyond the classic food fermentations. Here we discuss recent metabolic engineering strategies to improve particular cellular traits of LAB and to design LAB cell factories for the bioproduction of added value chemicals. Copyright © 2013 Elsevier Inc. All rights reserved.
Grounta, Athena; Harizanis, Paschalis; Mylonakis, Eleftherios; Nychas, George-John E.; Panagou, Efstathios Z.
2016-01-01
The use of Galleria mellonella as a model host to elucidate microbial pathogenesis and search for novel drugs and therapies has been well appreciated over the past years. However, the effect of microorganisms with functional appeal in the specific host remains scarce. The present study investigates the effect of treatment with selected lactic acid bacteria (LAB) with probiotic potential, as potential protective agents by using live or heat-killed cells at 6 and 24 h prior to infection with Listeria monocytogenes and Staphylococcus aureus or as potential therapeutic agents by using cell-free supernatants (CFS) after infection with the same pathogens. The employed LAB strains were Lactobacillus pentosus B281 and Lactobacillus plantarum B282 (isolated from table olive fermentations) along with Lactobacillus rhamnosus GG (inhabitant of human intestinal tract). Kaplan-Meier survival curves were plotted while the pathogen’s persistence in the larval hemolymph was determined by microbiological analysis. It was observed that the time (6 or 24 h) and type (live or heat-killed cells) of challenge period with LAB prior to infection greatly affected the survival of infected larvae. The highest decrease of L. monocytogenes population in the hemolymph was observed in groups challenged for 6 h with heat-killed cells by an average of 1.8 log units compared to non challenged larvae for strains B281 (p 0.0322), B282 (p 0.0325), and LGG (p 0.0356). In the case of S. aureus infection, the population of the pathogen decreased in the hemolymph by 1 log units at 8 h post infection in the groups challenged for 6 h with heat-killed cells of strains B281 (p 0.0161) and B282 (p 0.0096) and by 1.8 log units in groups challenged with heat-killed cells of LGG strain (p 0.0175). Further use of CFS of each LAB strain did not result in any significant prolonged survival but interestingly it resulted in pronounced decrease of L. monocytogenes in the hemolymph at 24 h and 48 h after infection by
NASA Astrophysics Data System (ADS)
Jamilah, It; Priyani, Nunuk; Lusia Natalia, Santa
2018-03-01
Lactic acid bacteria (LAB) has been added to various food products as a probiotic agent because it has been known to provide beneficial health effects in humans. In the application of LAB, cell viability often decreased as influenced by environment stresses. Encapsulation technique is one of the cell protection techniques using a coating material. Effective coating material is required to produce maximum protection of LAB cells. In this study, candidate of probiotic LAB (isolate US7) was encapsulated with alginate-mung bean flour and alginate-gram flour with inulin prebiotic by extrusion technique. Viability of encapsulated LAB cells were able to survive by up to 108CFU g‑1 after 4 weeks of storage at 4 °C. Beads were incubated in simulated liquid gastric acid (pH=2) for 2 hrs and simulated intestinal fluid (pH=6) for 3 hrs at 37 °C. The results showed that encapsulated LAB cells maintained the survival rate of 97% with the number of cells at 9.07 Log CFU g‑1in the simulated liquid gastric acid and then followed by releasing cells in simulated intestinal fluid. In general, this study indicates that encapsulation with alginate-mung bean flour and alginategram flour with inulin successfullyprotect probiotic bacteria against simulated human gastrointestinal conditions.
Jabłońska-Ryś, Ewa; Sławińska, Aneta; Radzki, Wojciech; Gustaw, Waldemar
2016-01-01
The available literature does not provide data on the application of probiotic strains in mushroom processing. The aim of the study was to evaluate the potential to use the L. plantarum 299v strain with documented probiotic properties in the process of lactic fermentation of button mushroom fruiting bodies (Agaricus bisporus). Fresh button mushroom fruiting bodies and cultures of lactic acid bacteria L. plantarum Ib and a probiotic strain L. plantarum 299v were the material analysed. Sensory evaluation was performed with a 5-point scale, an instrumental method of colour measurement based on the CIA L*a*b* scale, total phenolic compounds were determined with the Folin method, antioxidant properties were assayed with the DPPH radical test, and reducing power was determined using the FRAP method. After a week-long lactic fermentation, the pH value in the samples declined to a level of 3.6 (L. plantarum Ib) and 3.75 (L. plantarum 299v); these values persisted or decreased slightly during the period of maturation of the fermented samples under refrigeration. Fermented mushrooms were assigned high grades in the organoleptic evaluation. The colour analysis revealed significant changes in the values of the L*a*b* parameters in the fermented product, in comparison with fresh mushrooms. Blanching contributed to a significant decrease in the content of total phenolic compounds in the mushroom fruiting bodies and to a decline in antioxidant activity. Mushrooms fermented with the probiotic strain were characterised by higher phenolic compound content and higher antioxidant activity. L. plantarum 299v strain with documented probiotic properties can be applied in fermentation of button mushroom fruiting bodies. Products obtained with the use of both strains were characterised by good sensory properties. The type of strain used in the lactic fermentation of mushroom fruiting bodies had an effect on the phenolic compound content and antioxidant properties of the final product.
Mogna, Luca; Del Piano, Mario; Deidda, Francesca; Nicola, Stefania; Soattini, Liliana; Debiaggi, Rosaria; Sforza, Filomena; Strozzi, Gianpaolo; Mogna, Giovanni
2012-10-01
Lactobacilli and bifidobacteria are often associated with health-promoting effects. These live microorganisms, defined as probiotics, are commonly consumed as part of fermented foods, such as yoghurt and fermented milks, or as dietary supplements. Escherichia coli is a gram-negative, rod-shaped bacterium commonly found in the lower intestine of warm-blooded organisms. As a part of the normal gut microbiota, this microorganism colonizes the gastrointestinal tract of animals and humans within a few hours after birth. All E. coli strains can produce a wide variety of biogenic amines responsible for potentially harmful systemic intoxications. Enterohemorrhagic E. coli serotype O157:H7 is a pathotype of diarrhoeagenic strains with a large virulence plasmid pO157 able to produce 1 or more Shiga toxins. The overall aim of this study was to determine the inhibitory effects of different strains of probiotics on E. coli serotypes, including E. coli O157:H7 (CQ9485). In particular, the antagonistic activity of 4 Bifidobacterium strains (Probiotical SpA, Italy) and 16 lactic acid bacteria, more specifically 14 Lactobacillus spp. and 2 Streptococcus spp., was assessed against selected E. coli biotypes (ATCC 8739, ATCC 10536, ATCC 35218, and ATCC 25922). The diarrhoeagenic serotype O157:H7 was also tested. The experimental data collected demonstrated an in vitro significant inhibitory effect of 6 Lactobacillus strains, namely L. rhamnosus LR04, L. rhamnosus LR06, L. plantarum LP01, L. plantarum LP02, L. pentosus LPS01, and L. delbrueckii subsp. delbrueckii LDD01, and 2 Bifidobacterium strains, B. breve BR03 and B. breve B632. The inhibiting extent was slightly different among these strains, with L. delbrueckii subsp. delbrueckii LDD01 showing the highest activity on E. coli O157:H7. Most of the probiotics studied are able to antagonize the growth of the 5 strains of E. coli tested, including the O157:H7 biotype, well known for their characteristic to produce a wide variety of
Silva, I; Campos, F M; Hogg, T; Couto, J A
2011-08-01
To evaluate the effect of wine phenolic compounds on the production of volatile phenols (4-vinylphenol [4VP] and 4-ethylphenol [4EP]) from the metabolism of p-coumaric acid by lactic acid bacteria (LAB). Lactobacillus plantarum, Lactobacillus collinoides and Pediococcus pentosaceus were grown in MRS medium supplemented with p-coumaric acid, in the presence of different phenolic compounds: nonflavonoids (hydroxycinnamic and benzoic acids) and flavonoids (flavonols and flavanols). The inducibility of the enzymes involved in the p-coumaric acid metabolism was studied in resting cells. The hydroxycinnamic acids tested stimulated the capacity of LAB to synthesize volatile phenols. Growth in the presence of hydroxycinnamic acids, especially caffeic acid, induced the production of 4VP by resting cells. The hydroxybenzoic acids did not significantly affect the behaviour of the studied strains. Some of the flavonoids showed an effect on the production of volatile phenols, although strongly dependent on the bacterial species. Relatively high concentrations (1 g l(-1) ) of tannins inhibited the synthesis of 4VP by Lact. plantarum. Hydroxycinnamic acids were the main compounds stimulating the production of volatile phenols by LAB. The results suggest that caffeic and ferulic acids induce the synthesis of the cinnamate decarboxylase involved in the metabolism of p-coumaric acid. On the other hand, tannins exert an inhibitory effect. This study highlights the capacity of LAB to produce volatile phenols and that this activity is markedly influenced by the phenolic composition of the medium. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.
Purification of bacteriocins produced by lactic acid bacteria.
Saavedra, Lucila; Castellano, Patricia; Sesma, Fernando
2004-01-01
Bacteriocins are antibacterial substances of a proteinaceous nature that are produced by different bacterial species. Lactic acid bacteria (LAB) produce biologically active peptides or protein complexes that display a bactericidal mode of action almost exclusively toward Gram-positive bacteria and particularly toward closely related species. Generally they are active against food spoilage and foodborne pathogenic microorganisms including Bacillus cereus, Clostridium perfringens, Staphylococcus aureus, and Listeria monocytogenes. There is an increased tendency to use natural occurring metabolites to prevent the growth of undesirable flora in foodstuffs. These metabolites could replace the use of chemical additives such as sorbic acid, sulfur dioxide, nitrite, nitrate, and others. For instance, bacteriocins produced by LAB may be promising for use as bio-preservaties. Bacteriocins of lactic acid bacteria are typically cationic, hydrophobic peptides and differ widely in many characteristics including molecular weight, presence of particular groups of amino acids, pI, net positive charge, and post-translational modifications of certain amino acids. This heterogeneity within the LAB bacteriocins may explain the different procedures for isolation and purification developed so far. The methods most frequently used for isolation, concentration, and purification involve salt precipitation of bacteriocins from culture supernatants, followed by various combinations of gel filtration, ion-exchange chromatography, and reverse-phase high-performance liquid chromatography (RP-HPLC). In this chapter, a protocol is described that combines several methods used in our laboratory for the purification of two cationic bacteriocins, Lactocin 705AL and Enterocin CRL10, produced by Lactobacillus casei CRL705 and Enterococcus mundtii CRL10, respectively.
Makransky, Guido; Thisgaard, Malene Warming; Gadegaard, Helen
2016-01-01
To investigate if a virtual laboratory simulation (vLAB) could be used to replace a face to face tutorial (demonstration) to prepare students for a laboratory exercise in microbiology. A total of 189 students who were participating in an undergraduate biology course were randomly selected into a vLAB or demonstration condition. In the vLAB condition students could use a vLAB at home to 'practice' streaking out bacteria on agar plates in a virtual environment. In the demonstration condition students were given a live demonstration from a lab tutor showing them how to streak out bacteria on agar plates. All students were blindly assessed on their ability to perform the streaking technique in the physical lab, and were administered a pre and post-test to determine their knowledge of microbiology, intrinsic motivation to study microbiology, and self-efficacy in the field of microbiology prior to, and after the experiment. The results showed that there were no significant differences between the two groups on their lab scores, and both groups had similar increases in knowledge of microbiology, intrinsic motivation to study microbiology, as well as self-efficacy in the field of microbiology. Our data show that vLABs function just as well as face to face tutorials in preparing students for a physical lab activity in microbiology. The results imply that vLABs could be used instead of face to face tutorials, and a combination of virtual and physical lab exercises could be the future of science education.
Synthesis of High-Molecular-Weight Polyhydroxyalkanoates by Marine Photosynthetic Purple Bacteria
Higuchi-Takeuchi, Mieko; Morisaki, Kumiko; Toyooka, Kiminori; Numata, Keiji
2016-01-01
Polyhydroxyalkanoate (PHA) is a biopolyester/bioplastic that is produced by a variety of microorganisms to store carbon and increase reducing redox potential. Photosynthetic bacteria convert carbon dioxide into organic compounds using light energy and are known to accumulate PHA. We analyzed PHAs synthesized by 3 purple sulfur bacteria and 9 purple non-sulfur bacteria strains. These 12 purple bacteria were cultured in nitrogen-limited medium containing acetate and/or sodium bicarbonate as carbon sources. PHA production in the purple sulfur bacteria was induced by nitrogen-limited conditions. Purple non-sulfur bacteria accumulated PHA even under normal growth conditions, and PHA production in 3 strains was enhanced by nitrogen-limited conditions. Gel permeation chromatography analysis revealed that 5 photosynthetic purple bacteria synthesized high-molecular-weight PHAs, which are useful for industrial applications. Quantitative reverse transcription polymerase chain reaction analysis revealed that mRNA levels of phaC and PhaZ genes were low under nitrogen-limited conditions, resulting in production of high-molecular-weight PHAs. We conclude that all 12 tested strains are able to synthesize PHA to some degree, and we identify 5 photosynthetic purple bacteria that accumulate high-molecular-weight PHA molecules. Furthermore, the photosynthetic purple bacteria synthesized PHA when they were cultured in seawater supplemented with acetate. The photosynthetic purple bacteria strains characterized in this study should be useful as host microorganisms for large-scale PHA production utilizing abundant marine resources and carbon dioxide. PMID:27513570
Zadravec, Petra; Štrukelj, Borut
2015-01-01
Safety and probiotic properties make lactic acid bacteria (LAB) attractive hosts for surface display of heterologous proteins. Protein display on nonrecombinant microorganisms is preferred for therapeutic and food applications due to regulatory requirements. We displayed two designed ankyrin repeat proteins (DARPins), each possessing affinity for the Fc region of human IgG, on the surface of Lactococcus lactis by fusing them to the Usp45 secretion signal and to the peptidoglycan-binding C terminus of AcmA, containing lysine motif (LysM) repeats. Growth medium containing a secreted fusion protein was used to test its heterologous binding to 10 strains of species of the genus Lactobacillus, using flow cytometry, whole-cell enzyme-linked immunosorbent assay (ELISA), and fluorescence microscopy. The fusion proteins bound to the surfaces of all lactobacilli; however, binding to the majority of bacteria was only 2- to 5-fold stronger than that of the control. Lactobacillus salivarius ATCC 11741 demonstrated exceptionally strong binding (32- to 55-fold higher than that of the control) and may therefore be an attractive host for nonrecombinant surface display. Genomic comparison of the species indicated the exopolysaccharides of Lb. salivarius as a possible reason for the difference. Additionally, a 15-fold concentration-dependent increase in nonrecombinant surface display on L. lactis was demonstrated by growing bacteria with sublethal concentrations of the antibiotics chloramphenicol and erythromycin. Nonrecombinant surface display on LAB, based on LysM repeats, was optimized by selecting Lactobacillus salivarius ATCC 11741 as the optimal host and by introducing antibiotics as additives for increasing surface display on L. lactis. Additionally, effective display of DARPins on the surfaces of nonrecombinant LAB has opened up several new therapeutic possibilities. PMID:25576617
Toshimitsu, T; Ozaki, S; Mochizuki, J; Furuichi, K; Asami, Y
2017-04-01
Studies on the health-promoting effects of lactic acid bacteria (LAB) are numerous, but few provide examples of the relationship between LAB function and culture conditions. We verified the effect of differences in culture conditions on Lactobacillus plantarum OLL2712 functionality; this strain exhibits anti-inflammatory activity and preventive effects against metabolic disorders. We measured interleukin-10 (IL-10) and IL-12 production in murine immune cells treated with OLL2712 cells prepared under various culture conditions. The results showed that the IL-10-inducing activities of OLL2712 cells on murine immune cells differed dramatically between OLL2712 groups at different culture phases and using different culture medium components, temperatures, and neutralizing pHs. In particular, exponential-phase cells had much more IL-10-inducing activity than stationary-phase cells. We confirmed that the Toll-like receptor 2 (TLR2) stimulation activity of OLL2712 cells depended on culture conditions in conjunction with IL-10-inducing activity. We also demonstrated functional differences by culture phases in vivo ; OLL2712 cells at exponential phase had more anti-inflammatory activity and anti-metabolic-disorder effects on obese and diabetic mice than those by their stationary-phase counterparts. These results suggest that culture conditions affect the functionality of anti-inflammatory LAB. IMPORTANCE While previous studies demonstrated that culture conditions affected the immunomodulatory properties of lactic acid bacteria (LAB), few have comprehensively investigated the relationship between culture conditions and LAB functionality. In this study, we demonstrated several culture conditions of Lactobacillus plantarum OLL2712 for higher anti-inflammatory activity. We also showed that culture conditions concretely influenced the health-promoting functions of OLL2712 in vivo , particularly against metabolic disorders. Further, we characterized a novel mechanism by which
Quilodrán-Vega, Sandra Rayén; Villena, Julio; Valdebenito, José; Salas, María José; Parra, Cristian; Ruiz, Alvaro; Kitazawa, Haruki; García, Apolinaria
2016-06-01
Probiotics are usually isolated from the gastrointestinal tract of humans and animals. The search of probiotics in human milk is a recent field of research, as the existence of the human milk microbiome was discovered only about a decade ago. To our knowledge, no reports regarding the potential probiotic effect of bacteria from swine milk have been published. In this work, we isolated several lactic acid bacteria from swine milk and evaluated them for them potential as probiotics. Among the isolated strains, Lactobacillus curvatus TUCO-5E showed antagonistic effects against swine-associated gastrointestinal pathogens. TUCO-5E was able to reduce the growth of enterotoxigenic and enterohemorrhagic Escherichia coli strains as well as pathogenic salmonella. In vitro exclusion and displacement assays in intestinal epithelial cells showed a remarkable antagonistic effect for L. curvatus TUCO-5E against Salmonella sp. strain TUCO-I7 and Salmonella enterica ATCC 13096. Moreover, by using a mouse model of Salmonella infection, we were able to demonstrate that preventative administration of L. curvatus TUCO-5E for 5 consecutive days was capable of decreasing the number of Salmonella enterica serovar Typhimurium in the liver and spleen of treated mice, compared with the controls, and prevented dissemination of the pathogen to the blood stream. Therefore, we have demonstrated here that swine milk is an interesting source of beneficial bacteria. In addition, the results of this work suggest that L. curvatus TUCO-5E is a good candidate to study in vivo the protective effect of probiotics against intestinal infection and damage induced by Salmonella infection in the porcine host.
Lactic acid bacteria isolated from soy sauce mash in Thailand.
Tanasupawat, Somboon; Thongsanit, Jaruwan; Okada, Sanae; Komagata, Kazuo
2002-08-01
Fourteen sphere-shaped and 30 rod-shaped lactic acid bacteria were isolated from soy sauce mash of two factories in Thailand. These strains were separated into two groups, Group A and Group B, by cell shape and DNA-DNA similarity. Group A contained 14 tetrad-forming strains, and these strains were identified as Tetragenococcus halophilus by DNA similarity. Group B contained 30 rod-shaped bacteria, and they were further divided into four Subgroups, B1, B2, B3, and B4, and three ungrouped strains by phenotypic characteristics and DNA similarity. Subgroup B1 contained 16 strains, and these strains were identified as Lactobacillus acidipiscis by DNA similarity. Subgroup B2 included two strains, and the strains were identified as Lactobacillus farciminis by DNA similarity. Subgroup B3 contained five strains. The strains had meso-diaminopimelic acid in the cell wall, and were identified as Lactobacillus pentosus by DNA similarity. The strains tested produced DL-lactic acid from D-glucose. Subgroup B4 contained four strains. The strains had meso-diaminopimelic acid in the cell wall, and they were identified as Lactobacillus plantarum by DNA similarity. Two ungrouped strains were homofermentative, and one was heterofermentative. They showed a low degree of DNA similarity with the type strains tested, and were left unnamed. The distribution of lactic acid bacteria in soy sauce mash in Thailand is discussed.
The Occurrence of Beer Spoilage Lactic Acid Bacteria in Craft Beer Production.
Garofalo, Cristiana; Osimani, Andrea; Milanović, Vesna; Taccari, Manuela; Aquilanti, Lucia; Clementi, Francesca
2015-12-01
Beer is one of the world's most ancient and widely consumed fermented alcoholic beverages produced with water, malted cereal grains (generally barley and wheat), hops, and yeast. Beer is considered an unfavorable substrate of growth for many microorganisms, however, there are a limited number of bacteria and yeasts, which are capable of growth and may spoil beer especially if it is not pasteurized or sterile-filtered as craft beer. The aim of this research study was to track beer spoilage lactic acid bacteria (LAB) inside a brewery and during the craft beer production process. To that end, indoor air and work surface samples, collected in the brewery under study, together with commercial active dry yeasts, exhausted yeasts, yeast pellet (obtained after mature beer centrifugation), and spoiled beers were analyzed through culture-dependent methods and PCR-DGGE in order to identify the contaminant LAB species and the source of contamination. Lactobacillus brevis was detected in a spoiled beer and in a commercial active dry yeast. Other LAB species and bacteria ascribed to Staphylococcus sp., Enterobaceriaceae, and Acetobacter sp. were found in the brewery. In conclusion, the PCR-DGGE technique coupled with the culture-dependent method was found to be a useful tool for identifying the beer spoilage bacteria and the source of contamination. The analyses carried out on raw materials, by-products, final products, and the brewery were useful for implementing a sanitization plan to be adopted in the production plant. © 2015 Institute of Food Technologists®
Characterization of Lactobacillus brevis L62 strain, highly tolerant to copper ions.
Mrvčić, Jasna; Butorac, Ana; Solić, Ema; Stanzer, Damir; Bačun-Družina, Višnja; Cindrić, Mario; Stehlik-Tomas, Vesna
2013-01-01
Lactic acid bacteria (LAB) as starter culture in food industry must be suitable for large-scale industrial production and possess the ability to survive in unfavorable processes and storage conditions. Approaches taken to address these problems include the selection of stress-resistant strains. In food industry, LAB are often exposed to metal ions induced stress. The interactions between LAB and metal ions are very poorly investigated. Because of that, the influence of non-toxic, toxic and antioxidant metal ions (Zn, Cu, and Mn) on growth, acid production, metal ions binding capacity of wild and adapted species of Leuconostoc mesenteroides L3, Lactobacillus brevis L62 and Lactobacillus plantarum L73 were investigated. The proteomic approach was applied to clarify how the LAB cells, especially the adapted ones, protect themselves and tolerate high concentrations of toxic metal ions. Results have shown that Zn and Mn addition into MRS medium in the investigated concentrations did not have effect on the bacterial growth and acid production, while copper ions were highly toxic, especially in static conditions. Leuc. mesenteroides L3 was the most efficient in Zn binding processes among the chosen LAB species, while L. plantarum L73 accumulated the highest concentration of Mn. L. brevis L62 was the most copper resistant species. Adaptation had a positive effect on growth and acid production of all species in the presence of copper. However, the adapted species incorporated less metal ions than the wild species. The exception was adapted L. brevis L62 that accumulated high concentration of copper ions in static conditions. The obtained results showed that L. brevis L62 is highly tolerant to copper ions, which allows its use as starter culture in fermentative processes in media with high concentration of copper ions.
Yang, Xu; Yesil, Mustafa; Xiaoli, Lingzi; Dudley, Edward G.
2017-01-01
ABSTRACT Brevibacillus laterosporus OSY-I1 is a Gram-positive spore-forming bacterium isolated from soil. The bacterium produces brevibacillin, an antimicrobial lipopeptide effective against several drug-resistant Gram-positive bacteria. Here, we present the draft genome sequence of the strain OSY-I1 and the gene cluster responsible for the biosynthesis of brevibacillin. PMID:29025947
Antibiotic Production by Anaerobic Bacteria1
Sturgen, Nancy O.; Casida, L. E.
1962-01-01
Soils from aerobic and anaerobic sources were investigated for the possible presence of bacteria which produce antibiotics under anaerobic conditions of growth. The screening techniques devised for this study yielded 157 soil bacteria which, during anaerobic growth, produced antibiotic activity against aerobic test bacteria. Studies on choice of media, presence of oxygen, and changes in antibiotic activity during growth indicated that representative strains of these bacteria produced mixtures of antibiotics. The activity was heat labile. PMID:13918037
Ačai, P; Valík, L'; Medved'ová, A; Rosskopf, F
2016-09-01
Modelling and predicting the simultaneous competitive growth of Escherichia coli and starter culture of lactic acid bacteria (Fresco 1010, Chr. Hansen, Hørsholm, Denmark) was studied in milk at different temperatures and Fresco inoculum concentrations. The lactic acid bacteria (LAB) were able to induce an early stationary state in E. coli The developed model described and tested the growth inhibition of E. coli (with initial inoculum concentration 10(3) CFU/mL) when LAB have reached maximum density in different conditions of temperature (ranging from 12 ℃ to 30 ℃) and for various inoculum sizes of LAB (ranging from approximately 10(3) to 10(7) CFU/mL). The prediction ability of the microbial competition model (the Baranyi and Roberts model coupled with the Gimenez and Dalgaard model) was first performed only with parameters estimated from individual growth of E. coli and the LAB and then with the introduced competition coefficients evaluated from co-culture growth of E. coli and LAB in milk. Both the results and their statistical indices showed that the model with incorporated average values of competition coefficients improved the prediction of E. coli behaviour in co-culture with LAB. © The Author(s) 2015.
Tahir, Muhammad; Khalid, Umaira; Ijaz, Muhammad; Shah, Ghulam Mustafa; Naeem, Muhammad Asif; Shahid, Muhammad; Mahmood, Khalid; Ahmad, Naveed; Kareem, Fazal
2018-04-24
This study was aimed to investigate the effect of bio-organic phosphate either alone or in combination with phosphorus solubilizing bacteria strain (Bacillus MWT-14) on the growth and productivity of two wheat cultivars (Galaxy-2013 and Punjab-2011) along with recommended (150-100NPkgha -1 ) and half dose (75-50NPkgha -1 ) of fertilizers. The combined application of bio-organic phosphate and the phosphorous solubilizing bacteria strain at either fertilizer level significantly improved the growth, yield parameters and productivity of both wheat cultivars compared to non-inoculated control treatments. The cultivar Punjab-2011 produced the higher chlorophyll contents, crop growth rate, and the straw yield at half dose of NP fertilizer; while Galaxy-2013, with the combined application of bio-organic phosphate and phosphorous solubilizing bacteria under recommended NP fertilizer dose. Combined over both NP fertilizer levels, the combined use of bio-organic phosphate and phosphorous solubilizing bacteria enhanced the grain yield of cultivar Galaxy-2013 by 54.3% and that of cultivar Punjab-2011 by 83.3%. The combined application of bio-organic phosphate and phosphorous solubilizing bacteria also increased the population of phosphorous solubilizing bacteria, the soil organic matter and phosphorous contents in the soil. In conclusion, the combined application of bio-organic phosphate and phosphorous solubilizing bacteria offers an eco-friendly option to harvest the better wheat yield with low fertilizer input under arid climate. Copyright © 2018 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.
Diversity and distribution of culturable lactic acid bacterial species in Indonesian Sayur Asin.
Mangunwardoyo, Wibowo; Abinawanto; Salamah, Andi; Sukara, Endang; Sulistiani; Dinoto, Achmad
2016-08-01
Lactic acid bacteria (LAB) play important roles in processing of Sayur Asin (spontaneously fermented mustard). Unfortunately, information about LAB in Indonesian Sayur Asin, prepared by traditional manufactures which is important as baseline data for maintenance of food quality and safety, is unclear. The aim of this study was to describe the diversity and distribution of culturable lactic acid bacteria in Sayur Asin of Indonesia. Four Sayur Asin samples (fermentation liquor and fermented mustard) were collected at harvesting times (3-7 days after fermentation) from two traditional manufactures in Tulung Agung (TA) and Kediri (KDR), East Java provinces, Indonesia. LAB strains were isolated by using MRS agar method supplemented with 1% CaCO 3 and characterized morphologically. Identification of the strains was performed basedon 16S rDNA analysis and the phylogenetic tree was drawn to understand the phylogenetic relationship of the collected strains. Different profiles were detected in total count of the plates, salinity and pH of fermenting liquor of Sayur Asin in TA and KDR provinces. A total of 172 LAB isolates were successfully isolated and identified based on their 16S rDNA sequences. Phylogenetic analysis of 27 representative LAB strains from Sayur Asin showed that these strains belonged to 5 distinct species namely Lactobacilus farciminis (N=32), L. fermentum (N=4), L. namurensis (N=15), L. plantarum (N=118) and L. parafarraginis (N=1). Strains D5-S-2013 and B4-S-2013 showed a close phylogenetic relationship with L. composti and L. paralimentarius, respectively where as the sequence had slightly lower similarity of lower than 99%, suggesting that they may be classified into novel species and need further investigation due to exhibition of significant differences in their nucleotide sequences. Lactobacillus plantarum was found being dominant in all sayur asin samples. Lactobacilli were recognized as the major group of lactic acid bacteria in Sayur Asin
Wound infections with multi-drug resistant bacteria.
Pîrvănescu, H; Bălăşoiu, M; Ciurea, M E; Bălăşoiu, A T; Mănescu, R
2014-01-01
Wound infections remain a public health problem, despite the progress made on improving surgical techniques and antibiotic prophylaxis application. Misuse of antibiotics to prevent bacterial infections leads to increased bacterial resistance and their dissemination. The study refers to 470 samples taken from wound infections of which only multi-drug resistant strains were selected for study, using two special culture mediums (Metistaph-2 for methicillin-resistant staphylococci and ESBLs-Agar for extended-spectrum betalactamases secreting bacteria). Sensitivity of these strains was tested using the diffusion method. Of all studied samples, a rate of 27.6 bacterial strains showed multi-drug resistance. Among them stood primarily Staphylococcus aureus; both MRSA strains and ESBL Gram negative bacteria studied showed high resistance to aminoglycosides, quinolones, third generation cephalosporins and low to fourth generation cephalosporins. No vancomycin resitant nor vancomycin-intermediate Staphylococcus aureus strains were isolated. Knowing the antibiotic resistance is very useful in antibiotic "cycling"application, avoiding this way the emergence of increased resistant strains. Celsius.
Gulfam, Ali; Guo, Gang; Tajebe, Seare; Chen, Lei; Liu, Qinhua; Yuan, Xianjun; Bai, Yunfeng; Saho, Tao
2017-04-01
The poor fermentation quality of silage is an important issue for silage production during the high temperatures of summer. Pediococcus acidilactici GG13 (GG13) and Lactobacillus rhamnosus GG26 (GG26) isolated from Italian ryegrass (Lolium multiflorum Lam.) silage were characterised by morphological and physiological tests and 16S rRNA sequencing analysis, and their effects, along with those of a commercial lactic acid bacteria (LAB) inoculant (CB), on the fermentation quality of facultative halophyte Napier grass (Pennisetum purpureum Schumach) ensiled at 30 °C, 40 °C and 50 °C were studied, respectively. The strains GG13 and GG26 grew well at 50 °C and pH 3.5, and were tolerant to 6.5% NaCl. After ensiling for 50 days, the strains GG13 and GG26 and the CB decreased (P < 0.001) the pH and acetic acid and ammonia-N contents and increased (P < 0.001) the lactic acid contents at 30 °C, and decreased (P < 0.001) the ammonia-N contents at 40 °C in Napier grass. CB did not affect the fermentation quality at 50 °C, whereas both isolated strains improved the fermentation quality of Napier grass silage as indicated by the lower (P < 0.001) pH, butyric acid and ammonia-N contents and higher (P < 0.001) lactic acid contents. The strain GG13 is better than GG26 with regard to improvement in fermentation quality of Napier grass silage. The results of this study suggested that strain GG13 is a good LAB inoculant for producing well-fermented silages during the high temperatures of summer times. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.
Information about the Current Strain of Clostridium difficile
... rubs may not be as effective against spore-forming bacteria. Contact precautions Environmental cleaning and disinfection strategies. ... Detection of VISA/VRSA S.E.A.R.C.H. Labs Role in the Search and Containment of ...
Fasseas, Michael K; Fasseas, Costas; Mountzouris, Konstantinos C; Syntichaki, Popi
2013-03-01
This study examined the effects of three lactic acid bacteria (LAB) strains on the nematode Caenorhabditis elegans. Lactobacillus salivarius, Lactobacillus reuteri, and Pediococcus acidilactici were found to inhibit the development and growth of the worm. Compared to Escherichia coli used as the control, L. reuteri and P. acidilactici reduced the lifespan of wild-type and short-lived daf-16 worms. On the contrary, L. salivarius extended the lifespan of daf-16 worms when used live, but reduced it as UV-killed bacteria. The three LAB induced the expression of genes involved in pathogen response and inhibited the growth of tumor-like germ cells, without affecting DAF16 localization or increasing corpse cells. Our results suggest the possible use of C. elegans as a model for studying the antitumor attributes of LAB. The negative effects of these LAB strains on the nematode also indicate their potential use against parasitic nematodes.
Hayashi, Atsushi; Kimura, Makoto; Nakamura, Yusaku; Yasui, Hisako
2009-05-01
We investigated the anti-allergic effects of one strain (T120) of a lactic acid bacteria (LAB) isolated from Mongolian fermented milk using atopic dermatitis (AD) model mice (NC/Nga mice). Strain T120 has already been identified as Enterococcus faecium and shown to induce strong production of IL-12 (Kimura et al. 2006). In in vitro studies, strain T120 suppressed total IgE production and induced IL-12 and IFN-gamma production by splenocytes of NC/Nga mice. The additional examination of various neutralization antibodies was performed to elucidate in detail the mechanism of depressed IgE production by strain T120. As a result, it became clear that IL-12 induced by strain T120 increased production of IFN-gamma and total IgE production was mainly controlled by the IFN-gamma. In order to define the cells which produce IL-12 powerfully by this strain, antigen-presenting cells (APCs) such as macrophages and dendritic cells (DCs) were removed from the splenocytes, and the reactivity of these cells to the strain was examined. Induction of IL-12 and IFN-gamma by strain T120 became significantly very low by removal of APCs from splenocytes. Therefore, it was clear that strain T120 acted on APCs and induced production of IL-12. Further, this strain enhanced the production of IL-10 by splenocytes. In in vivo studies, intraperitoneal injection of strain T120 inhibited serum IgE elevation and atopic dermatitis symptoms in NC/Nga mice. These results suggest that an anti-allergic effect of strain T120 depends on the increased production of IL-12 by APCs activated by the strain and following the increased production of IFN-gamma. Further, activation of regulatory T cells by strain T120 may inhibit atopic disease.
Numerical taxonomy of phenanthrene-degrading bacteria isolated from the Chesapeake Bay
DOE Office of Scientific and Technical Information (OSTI.GOV)
West, P.A.; Okpokwasili, G.C.; Brayton, P.R.
1984-11-01
Phenanthrene-degrading bacteria were isolated from Chesapeake Bay samples by the use of a solid medium which had been overlaid with an ethanol solution of phenanthrene before inoculation. Eighteen representative strains of phenanthrene-degrading bacteria with 21 type and reference bacteria were examined for 123 characteristics representing physiological, biochemical, and nutritional properties. Relationships between strains were computed with several similarity coefficients. The phenogram constructed by unweighted-pair-group arithmetic average linkage and use of the simple Jaccard (S/sub J/) coefficient was used to identify seven phena. Phenanthrene-degrading bacteria were identified as Vibrio parahaemolyticus and Vibrio fluvialis by their clustering with type and reference strains.more » Several phenanthrene-degrading bacteria resembled Enterobacteriaceae family members, although some Vibrio-like phenanthrene degraders could not be identified. 22 references, 1 figure, 2 tables.« less
Soria, M Cecilia; Audisio, M Carina
2014-12-01
Bacillus cereus is an endospore-forming, Gram-positive bacterium able to cause foodborne diseases. Lactic acid bacteria (LAB) are known for their ability to synthesize organic acids and bacteriocins, but the potential of these compounds against B. cereus has been scarcely documented in food models. The present study has examined the effect of the metabolites produced by Lactobacillus johnsonii CRL1647 and Enterococcus faecium SM21 on the viability of select B. cereus strains. Furthermore, the effect of E. faecium SM21 metabolites against B. cereus strains has also been investigated on a rice food model. L. johnsonii CRL1647 produced 128 mmol/L of lactic acid, 38 mmol/L of acetic acid and 0.3 mmol/L of phenyl-lactic acid. These organic acids reduced the number of vegetative cells and spores of the B. cereus strains tested. However, the antagonistic effect disappeared at pH 6.5. On the other hand, E. faecium SM21 produced only lactic and acetic acid (24.5 and 12.2 mmol/L, respectively) and was able to inhibit both vegetative cells and spores of the B. cereus strains, at a final fermentation pH of 5.0 and at pH 6.5. This would indicate the action of other metabolites, different from organic acids, present in the cell-free supernatant. On cooked rice grains, the E. faecium SM21 bacteriocin(s) were tested against two B. cereus strains. Both of them were significantly affected within the first 4 h of contact; whereas B. cereus BAC1 cells recovered after 24 h, the effect on B. cereus 1 remained up to the end of the assay. The LAB studied may thus be considered to define future strategies for biological control of B. cereus.
Bacteriophage sensitivity patterns among bacteria isolated from marine waters
NASA Astrophysics Data System (ADS)
Moebus, K.; Nattkemper, H.
1981-09-01
Phage-host cross-reaction tests were performed with 774 bacterial strains and 298 bacteriophages. The bacteria (bacteriophages) were isolated at different times from water samples collected in the Atlantic Ocean between the European continental shelf and the Sargasso Sea: 733 (258) strains; in the North Sea near Helgoland: 31 (31) strains; and in the Bay of Biscay: 10 (9) strains. Of the Atlantic Ocean bacteria 326 were found to be susceptible to one or more Atlantic Ocean bacteriophage(s). The bacteriophage sensitivity patterns of these bacteria vary considerably, placing 225 of them in two large clusters of bacteriophage-host systems. Taking all into account, 250 of the 326 Atlantic Ocean bacteria are different from each other. This high degree of variation among the bacteria distinguishes microbial populations derived from widely separated eastern and western regions of the Atlantic Ocean. It also sets apart from each other the populations derived from samples collected at successive stations some 200 miles apart, although to a lesser degree. With bacterial populations found from samples collected on the way back and forth between Europe and the Sargasso Sea a gradual change was observed from "western" phage sensitivity patterns to "eastern" ones. Sixty-nine Atlantic Ocean bacteria are sensitive to bacteriophages isolated from the North Sea and the Bay of Biscay; of these only 26 strains are also susceptible to Atlantic Ocean phages. The interpretation of the results is based on the hydrographical conditions prevailing in the northern Atlantic Ocean including the North Sea, and on the assumption that the microbial populations investigated have undergone genetic changes while being transported within water masses from west to east.
Isolation of lactic acid bacteria with potential protective culture characteristics from fruits
NASA Astrophysics Data System (ADS)
Hashim, Nurul Huda; Sani, Norrakiah Abdullah
2015-09-01
Lactic acid bacteria are also known as beneficial microorganisms abundantly found in fermented food products. In this study, lactic acid bacteria were isolated from fresh cut fruits obtained from local markets. Throughout the isolation process from 11 samples of fruits, 225 presumptive lactic acid bacteria were isolated on MRS agar medium. After catalase and oxidase tests, 149 resulted to fit the characteristics of lactic acid bacteria. Further identification using Gram staining was conducted to identify the Gram positive bacteria. After this confirmation, the fermentation characteristics of these isolates were identified. It was found that 87 (58.4%) isolates were heterofermentative, while the rest of 62 (41.6%) are homofermentative lactic acid bacteria. Later, all these isolates were investigated for the ability to inhibit growth of Staphylococcus aureus using agar spot assay method. Seven (4.7%) isolates showed strong antagonistic capacity, while 127 (85.2%) and 8 (5.4%) isolates have medium and weak antagonistic capacity, respectively. The other 7 (4.7%) isolates indicated to have no antagonistic effect on S. aureus. Results support the potential of LAB isolated in this study which showed strong antagonistic activity against S. aureus may be manipulated to become protective cultures in food products. While the homofermentative or heterofermentative LAB can be utilized in fermentation of food and non-food products depending on the by-products required during the fermentation.
Samelis, John; Lianou, Alexandra; Kakouri, Athanasia; Delbès, Céline; Rogelj, Irena; Bogovic-Matijasić, Bojana; Montel, Marie-Christine
2009-04-01
The microbiological quality, safety, and composition of mixtures of ewe's and goat's milk (90:10) used for cheesemaking were evaluated before and after thermization at 60 and 67 degrees C for 30 s. Such mild thermal treatments are commonly applied to reduce natural contaminants of raw milk before processing for traditional hard Greek cheeses. Raw milk samples had an average total bacterial count of 7.3 log CFU/ml; most of these bacteria were lactic acid bacteria (LAB) and pseudomonads. The LAB flora of raw milk was dominated by enterococci (40.8%), followed by lactococci (20.4%), leuconostocs (18.4%), and mesophilic lactobacilli (10.2%). Enterococcus faecalis (30.1%) and Enterococcus faecium (13.7%) were the most common LAB isolates, followed by Enterococcus durans, Lactococcus lactis subsp. lactis, Lactobacillus plantarum, and Leuconostoc lactis. Thermization at 60 degrees C for 30 s was effective for reducing raw milk contamination by enterobacteria (5.1 log CFU/ml), coagulase-positive staphylococci (3.3 log CFU/ml), and Listeria (present in 25-ml samples) to safe levels, but it also reduced mesophilic lactococci, leuconostocs, lactobacilli, and selected enterococci (72.0%) in thermized milk. Thermization at 67 degrees C for 30 s had a major inactivation effect on all bacterial groups. Two nisin-producing L. lactis subsp. lactis strains (M78 and M104) were isolated from raw milk, but neither nisin-producing nor other bacteriocin-producing LAB strains were isolated from thermized milk. Thus, thermization treatments control harmful bacteria but also may have a negative impact on milk quality by reducing desirable LAB and the biodiversity of raw milk bacteria overall, inactivating potentially protective LAB strains and enhancing the ability of potentially pathogenic enterococci to grow in fresh cheese curds.
Love the Lab, Hate the Lab Report?
ERIC Educational Resources Information Center
Bjorn, Genevive
2018-01-01
In the author's large, urban high school, enrollment in a laboratory science is mandatory. While the student participation rate for lab activities is over 98%, the turn-in rate for traditional lab reports averages just 35% to 85%. Those students who don't produce a lab report miss a critical opportunity to improve their skills in scientific…
Yang, Dan-Dan; Li, Qian; Huang, Jing-Jing; Chen, Min
2012-11-01
Soil and saline water samples were collected from the Daishan Saltern of East China, and the halophilic bacteria were isolated and cultured by using selective media, aimed to investigate the diversity and enzyme-producing activity of culturable halophilic bacteria in saltern environment. A total of 181 strains were isolated by culture-dependent method. Specific primers were used to amplify the 16S rRNA gene of bacteria and archaea. The operation taxonomy units (OTUs) were determined by ARDRA method, and the representative strain of each OTU was sequenced. The phylogenetic position of all the isolated strains was determined by 16S rRNA sequencing. The results showed that the isolated 181 strains displayed 21 operational taxonomic units (OTUs), of which, 12 OTUs belonged to halophilic bacteria, and the others belonged to halophilic archaea. Phylogenetic analysis indicated that there were 7 genera presented among the halophilic bacteria group, and 4 genera presented among the halophilic archaea group. The dominant halophilic strains were of Halomonas and Haloarcula, with 46.8% in halophilic bacteria and 49.1% in halophilic archaea group, respectively. Enzyme-producing analysis indicated that most strains displayed enzyme-producing activity, including the activities of producing amylase, proteinase and lipase, and the dominant strains capable of enzyme-producing were of Haloarcula. Our results showed that in the environment of Daishan Saltern, there existed a higher diversity of halophilic bacteria, being a source sink for screening enzyme-producing bacterial strains.
Cha, Kyoung Je; Kim, Dong Sung
2011-10-01
In this paper, we propose a novel portable and disposable pressure pump using a porous polydimethylsiloxane (PDMS) sponge and demonstrate its application to a microfluidic lab-on-a-chip. The porous PDMS sponge was simply fabricated by a sugar leaching technique based on capillary suction of pre-cured PDMS into lumps of sugar, thereby enabling us to achieve the porous PDMS sponge composed of interconnected micropores. To indicate the characteristics of the porous PDMS sponge and pump, we measured the average porosities of them whose values were 0.64 and 0.34, respectively. A stress-strain relationship of the fabricated portable pressure pump represented a linear behavior in the compressive strain range of 0 to 20%. Within this range, a pumping volume of the pressure pump could be linearly controlled by the compressed strain. Finally, the fabricated porous PDMS pump was successfully demonstrated as a portable pressure pump for a disposable microfluidic lab-on-a-chip for efficient detection of agglutination. The proposed portable pressure pump can be potentially applicable to various disposable microfluidic lab-on-a-chip systems.
Michalak, Magdalena; Gustaw, Klaudia; Waśko, Adam; Polak-Berecka, Magdalena
2018-01-01
The present work is the first report on spontaneous fermentation of curly kale and characteristics of autochthonous lactic acid bacteria (LAB). Our results indicate that curly kale fermentation is the new possibility of the technological use of this vegetable. Bacteria representing ten different species were isolated from three phases of curly kale fermentation and identified by MALDI-TOF mass spectrometry and 16S rRNA gene sequencing. Among them, four species were identified as Lactobacillus spp. (Lb. plantarum 332, Lb. paraplantarum G2114, Lb. brevis R413, Lb. curvatus 154), two as Weissella spp. (W. hellenica 152, W. cibaria G44), two as Pediococcus spp. (P. pentosaceus 45AN, P. acidilactici 2211), one as Leuconostoc mesenteroides 153, and one as Lactococcus lactis 37BN. The functional properties of isolates, i.e. acid, NaCl and bile salt tolerance, enzyme activities, adhesion to hydrocarbons, and antibiotic resistance, were examined. Among the tested strains, Lb. plantarum 332, Lb. paraplantarum G2114, P. pentosaceus 2211, and Lb. brevis R413 exhibited the best hydrophobicity value and high tolerance to bile salts, NaCl, and low pH. Copyright © 2017 Elsevier GmbH. All rights reserved.
Hisbergues, M; Magi, M; Rigaux, P; Steuve, J; Garcia, L; Goudercourt, D; Pot, B; Pestel, J; Jacquet, A
2007-09-01
Lactic acid bacteria (LAB) were reported to reduce some allergic manifestations in mice and humans but their impact on the aeroallergen-dependent immune mechanisms is still debated. The potential capacities of Lactobacillus plantarum NCIMB8826 to reduce the allergic response induced by Der p 1, the major house dust mite allergen of Dermatophagoides pteronyssinus, were evaluated in vivo and in vitro. Methods First, the effect of the intranasal co-administration of LAB and purified Der p 1 allergen before a sensitization protocol was evaluated. The allergen-specific antibody and cellular responses as well as airway inflammation were measured. Second, the impact of LAB on the cytokine profile of spleens cells from Der p 1-sensitized mice was assessed. Third, upon stimulation with LAB, the levels of cytokine produced by dendritic cells derived from the bone marrow (BMDCs) of wild-type, Toll-like receptor 2 (TLR2)-, TLR4- and MyD88-KO mice were compared. Results The co-application of L. plantarum and Der p 1 induced a T-helper type 1 (Th1)-biased allergen-specific IgG response, the absence of specific IgE response and favoured the production of INF-gamma upon allergen re-stimulation. Moreover, the previous LAB administration reduced the development of bronchoalveolar lavage eosinophilia usually induced by aerosol exposure. Additionally, the studied LAB strain was shown to modify in vitro the cytokine level produced by Der p 1-sensitized spleen cells mainly towards a Th1 profile. Finally, L. plantarum stimulated high IL-12 and moderate IL-10 production in mouse BMDCs notably through the TLR2-, MyD88-dependent and TLR4-independent pathway. In vivo co-administration of probiotic LAB with Der p 1 might prevent the development of the mite allergic response. The probiotic L. plantarum was shown to display in vitro therapeutic potentials for the treatment of allergy and to trigger the immune system by a TLR2- and MyD88-dependent signalling pathway.
del Carmen, Silvina; de Moreno de LeBlanc, Alejandra; Martin, Rebeca; Chain, Florian; Langella, Philippe; Bermúdez-Humarán, Luis G.
2014-01-01
The aims of this study were to develop strains of lactic acid bacteria (LAB) having both immunomodulatory and antioxidant properties and to evaluate their anti-inflammatory effects both in vitro, in different cellular models, and in vivo, in a mouse model of colitis. Different Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus strains were cocultured with primary cultures of mononuclear cells. Analysis of the pro- and anti-inflammatory cytokines secreted by these cells after coincubation with candidate bacteria revealed that L. delbrueckii subsp. bulgaricus CRL 864 and S. thermophilus CRL 807 display the highest anti-inflammatory profiles in vitro. Moreover, these results were confirmed in vivo by the determination of the cytokine profiles in large intestine samples of mice fed with these strains. S. thermophilus CRL 807 was then transformed with two different plasmids harboring the genes encoding catalase (CAT) or superoxide dismutase (SOD) antioxidant enzymes, and the anti-inflammatory effects of recombinant streptococci were evaluated in a mouse model of colitis induced by trinitrobenzenesulfonic acid (TNBS). Our results showed a decrease in weight loss, lower liver microbial translocation, lower macroscopic and microscopic damage scores, and modulation of the cytokine production in the large intestines of mice treated with either CAT- or SOD-producing streptococci compared to those in mice treated with the wild-type strain or control mice without any treatment. Furthermore, the greatest anti-inflammatory activity was observed in mice receiving a mixture of both CAT- and SOD-producing streptococci. The addition of L. delbrueckii subsp. bulgaricus CRL 864 to this mixture did not improve their beneficial effects. These findings show that genetically engineering a candidate bacterium (e.g., S. thermophilus CRL 807) with intrinsic immunomodulatory properties by introducing a gene expressing an antioxidant enzyme enhances its anti
Ventorino, Valeria; Cavella, Silvana; Fagnano, Massimo; Brugno, Rachele
2013-01-01
In the last few years the need to produce food with added value has fueled the search for new ingredients and health-promoting compounds. In particular, to improve the quality of bakery products with distinct nutritional properties, the identification of new raw materials, appropriate technologies, and specific microbial strains is necessary. In this study, different doughs were prepared, with 10% and 20% flour from immature wheat grain blended with type “0 America” wheat flour. Immature flour was obtained from durum wheat grains harvested 1 to 2 weeks after anthesis. Doughs were obtained by both the straight-dough and sourdough processes. Two selected exopolysaccharide-producing strains of lactic acid bacteria (LAB), Leuconostoc lactis A95 and Lactobacillus curvatus 69B2, were used as starters. Immature flour contained 2.21 g/100 g (dry weight) of fructo-oligosaccharides. Twenty percent immature flour in dough resulted in a shorter leavening time (4.23 ± 0.03 h) than with the control and dough with 10% immature flour. The total titratable acidity of sourdough with 20% immature flour was higher (12.75 ± 0.15 ml 0.1 N NaOH) than in the control and sourdough with 10% immature wheat flour (9.20 ml 0.1 N NaOH). Molecular analysis showed that all samples contained three LAB species identified as L. lactis, L. curvatus, and Pediococcus acidilactici. A larger amount of exopolysaccharide was found in sourdough obtained with 20% immature flour (5.33 ± 0.032 g/kg), positively influencing the exopolysaccharide content of the bread prepared by the sourdough process (1.70 ± 0.03 g/kg). The addition of 20% immature flour also led to a greater presence of fructo-oligosaccharides in the bread (900 mg/100 g dry weight), which improved its nutritional characteristics. While bread volume decreased as the concentration of immature wheat flour increased, its mechanical characteristics (stress at a strain of 30%) were the same in all samples obtained with different percentages
Effect of smokeless tobacco products on human oral bacteria growth and viability
Liu, Min; Jin, Jinshan; Pan, Hongmiao; Feng, Jinhui; Cerniglia, Carl E.; Yang, Maocheng; Chen, Huizhong
2017-01-01
To evaluate the toxicity of smokeless tobacco products (STPs) on oral bacteria, seven smokeless tobacco aqueous extracts (STAEs) from major brands of STPs and three tobacco-specific N-nitrosamines (TSNAs) were used in a growth and viability test against 38 oral bacterial species or subspecies. All seven STAEs showed concentration-dependent effects on the growth and viability of tested oral bacteria under anaerobic culture conditions, although there were strain-to-strain variations. In the presence of 1 mg/ml STAEs, the growth of 4 strains decreased over 0.32–2.14 log10 fold, while 14 strains demonstrated enhanced growth of 0.3–1.76 log10 fold, and the growth of 21 strains was not significantly affected. In the presence of 10 mg/ml STAEs, the growth of 17 strains was inhibited 0.3–2.11 log10 fold, 18 strains showed enhanced growth of 0.3–0.97 log10 fold, and 4 strains were not significantly affected. In the presence of 50 mg/ml STAEs, the growth of 32 strains was inhibited 0.3–2.96 log10 fold, 8 strains showed enhanced growth of 0.3–1.0 log10 fold, and 2 strains were not significantly affected. All seven STAEs could promote the growth of 4 bacterial strains, including Eubacterium nodatum, Peptostreptococcus micros, Streptococcus anginosus, and Streptococcus constellatus. Exposure to STAEs modulated the viability of some bacterial strains, with 21.1–66.5% decrease for 4 strains at 1 mg/ml, 20.3–85.7% decrease for 10 strains at 10 mg/ml, 20.0–93.3% decrease for 27 strains at 50 mg/ml, and no significant effect for 11 strains at up to 50 mg/ml. STAEs from snuffs inhibited more tested bacterial strains than those from snus indicating that the snuffs may be more toxic to the oral bacteria than snus. For TSNAs, cell growth and viability of 34 tested strains were not significantly affected at up to 100 μg/ml; while the growth of P. micros was enhanced 0.31–0.54 log10 fold; the growth of Veillonella parvula was repressed 0.33–0.36 log10 fold; and the
Lee, Sang H; Lee, Seonki; Lee, Kibaek; Nahm, Chang H; Kwon, Hyeokpil; Oh, Hyun-Suk; Won, Young-June; Choo, Kwang-Ho; Lee, Chung-Hak; Park, Pyung-Kyu
2016-08-16
Recently, membrane bioreactors (MBRs) with quorum quenching (QQ) bacteria entrapping beads have been reported as a new paradigm in biofouling control because, unlike conventional post-biofilm control methods, bacterial QQ can inhibit biofilm formation through its combined effects of physical scouring of the membrane and inhibition of quorum sensing (QS). In this study, using a special reporter strain (Escherichia coli JB525), the interaction between QS signal molecules and quorum quenching bacteria entrapping beads (QQ-beads) was elucidated through visualization of the QS signal molecules within a QQ-bead using a fluorescence microscope. As a result, under the conditions considered in this study, the surface area of QQ-media was likely to be a dominant parameter in enhancing QQ activity over total mass of entrapped QQ bacteria because QQ bacteria located near the core of a QQ-bead were unable to display their QQ activities. On the basis of this information, a more efficient QQ-medium, a QQ hollow cylinder (QQ-HC), was designed and prepared. In batch experiments, QQ-HCs showed greater QQ activity than QQ-beads as a result of their higher surface area and enhanced physical washing effect because of their larger impact area against the membrane surface. Furthermore, it was shown that such advantages of QQ-HCs resulted in more effective mitigation of membrane fouling than from QQ-beads in lab-scale continuous MBRs.
Sandes, Sávio; Alvim, Luige; Silva, Bruno; Acurcio, Leonardo; Santos, Cinara; Campos, Márcia; Santos, Camila; Nicoli, Jacques; Neumann, Elisabeth; Nunes, Álvaro
2017-07-01
From the birth, since their mucosal microbiota and immune system are not fully developed, newborn calves are susceptible to several mucosal pathogenic microorganisms. Operating through humoral and non-humoral mechanisms in the host, several lactic acid bacteria strains bearing probiotic features are often employed in livestock as food supplement, improving animal production performance, promoting health and reducing the severity of mucosal infections. Accordingly, we isolated, species-level identified and screened for their probiotic potentials seventy lactic acid bacteria strains from upper airway, vaginal and intestinal mucosa of healthy calves. Based on in vitro approaches, we selected three strains: Lactobacillus fermentum V3B-08 isolated from upper airway mucosa, Weissella hellenica V1V-30 isolated from vaginal mucosa and Lactobacillus farciminis B4F-06 isolated from intestinal mucosa were used to mono-colonize germ-free mice in the same site in which these strains were isolated, aiming to characterize their immunomodulatory features. These strains were able to colonize germ-free mice mucosa and trigger sIgA synthesis at a local level, in addition to stimulating, in different ways, adaptive immune responses at a systemic level. Copyright © 2017 Elsevier GmbH. All rights reserved.
Antibiotic-Resistant Bacteria.
ERIC Educational Resources Information Center
Longenecker, Nevin E.; Oppenheimer, Dan
1982-01-01
A study conducted by high school advanced bacteriology students appears to confirm the hypothesis that the incremental administration of antibiotics on several species of bacteria (Escherichia coli, Staphylococcus epidermis, Bacillus sublitus, Bacillus megaterium) will allow for the development of antibiotic-resistant strains. (PEB)
[Experimental interaction of halophilic prokaryotes and opportunistic bacteria in brine].
Selivanova, E A; Nemtseva, N V
2013-01-01
Study the effect of extremely halophilic archaea and moderately halophilic bacteria on preservation of opportunistic bacteria in brine. 17 strains of moderately halophilic bacteria and 2 strains of extremely halophilic archaea were isolated from continental hypersaline lake Razval of Sol-Iletsk area of Orenburg Region. Identification of pure cultures of prokaryotes was carried out taking into account their phenotype properties and based on determination of 16S RNA gene sequence. The effect of halophilic prokaryote on elimination of Escherichia coli from brine was evaluated during co-cultivation. Antagonistic activity of cell extracts of the studied microorganisms was evaluated by photometric method. A more prolonged preservation of an E. coli strain in brine in the presence of live cells of extremely halophilic archaea Halorubrum tebenquichense and moderately halophilic bacteria Marinococcus halophilus was established. Extracts of cells of extremely halophilic archaea and moderately halophilic bacteria on the contrary displayed antagonistic activity. The protective effect of live cells of halophilic prokaryotes and antagonistic activity of their cell extracts change the period of conservation of opportunistic bacteria in brine that regulates inter-microbial interactions and changes the period of self-purification that reflects the sanitary condition of a hypersaline water body.
Genomic encyclopedia of bacteria and archaea: sequencing a myriad of type strains.
Kyrpides, Nikos C; Hugenholtz, Philip; Eisen, Jonathan A; Woyke, Tanja; Göker, Markus; Parker, Charles T; Amann, Rudolf; Beck, Brian J; Chain, Patrick S G; Chun, Jongsik; Colwell, Rita R; Danchin, Antoine; Dawyndt, Peter; Dedeurwaerdere, Tom; DeLong, Edward F; Detter, John C; De Vos, Paul; Donohue, Timothy J; Dong, Xiu-Zhu; Ehrlich, Dusko S; Fraser, Claire; Gibbs, Richard; Gilbert, Jack; Gilna, Paul; Glöckner, Frank Oliver; Jansson, Janet K; Keasling, Jay D; Knight, Rob; Labeda, David; Lapidus, Alla; Lee, Jung-Sook; Li, Wen-Jun; Ma, Juncai; Markowitz, Victor; Moore, Edward R B; Morrison, Mark; Meyer, Folker; Nelson, Karen E; Ohkuma, Moriya; Ouzounis, Christos A; Pace, Norman; Parkhill, Julian; Qin, Nan; Rossello-Mora, Ramon; Sikorski, Johannes; Smith, David; Sogin, Mitch; Stevens, Rick; Stingl, Uli; Suzuki, Ken-Ichiro; Taylor, Dorothea; Tiedje, Jim M; Tindall, Brian; Wagner, Michael; Weinstock, George; Weissenbach, Jean; White, Owen; Wang, Jun; Zhang, Lixin; Zhou, Yu-Guang; Field, Dawn; Whitman, William B; Garrity, George M; Klenk, Hans-Peter
2014-08-01
Microbes hold the key to life. They hold the secrets to our past (as the descendants of the earliest forms of life) and the prospects for our future (as we mine their genes for solutions to some of the planet's most pressing problems, from global warming to antibiotic resistance). However, the piecemeal approach that has defined efforts to study microbial genetic diversity for over 20 years and in over 30,000 genome projects risks squandering that promise. These efforts have covered less than 20% of the diversity of the cultured archaeal and bacterial species, which represent just 15% of the overall known prokaryotic diversity. Here we call for the funding of a systematic effort to produce a comprehensive genomic catalog of all cultured Bacteria and Archaea by sequencing, where available, the type strain of each species with a validly published name (currently∼11,000). This effort will provide an unprecedented level of coverage of our planet's genetic diversity, allow for the large-scale discovery of novel genes and functions, and lead to an improved understanding of microbial evolution and function in the environment.
NASA Astrophysics Data System (ADS)
Gong, Mingfu; Lin, Tianxing; Huang, Jiao; Zeng, Bo
2018-04-01
Konjac soft rot has a serious impact on the production of konjac, the use of endophytic bacteria to inhibit konjac soft rot bacteria have many advantages. Twenty-three endophytic bacteria isolated from the medicinal plants were used to determine the antagonistic effects of endophytic bacteria on konjac soft rot in the Oxford cups. Of the strain. The results showed that 23 strains of endophytic bacteria had different antagonistic activities against konjac soft rot, 8 strains had very significant antibacterial effect, and YC06 and YC09 had strong antibacterial ability of two endophytic bacteria. Konjac soft rot fungi also have a strong antibacterial capacity.
Fish skin bacteria: Colonial and cellular hydrophobicity.
Sar, N; Rosenberg, E
1987-05-01
Bacteria were desorbed from the skin of healthy, fast-swimming fish by several procedures, including brief exposure to sonic oscillation and treatment with nontoxic surface active agents. The surface properties of these bacteria were studied by measuring their adhesion to hexadecane, as well as by a newly developed, simple method for studying the hydrophobicity of bacterial lawns. This method, referred to as the "Direction of Spreading" (DOS) method, consists of recording the direction to which a water drop spreads when introduced at the border between bacterial lawns and other surfaces. Of the 13 fish skin isolates examined, two strains were as hydrophobic as polystyrene by the DOS method. Suspended cells of one of these strains adhered strongly to hexadecane (84%), whereas cells of the other strain adhered poorly (13%). Another strain which was almost as hydrophobic as polystyrene by the DOS method did not adhere to hexadecane at all. Similarly, lawns of three other strains were more hydrophobic than glass by the DOS method, but cell suspensions prepared from these colonies showed little or no adhesion to hexadecane. The high colonial but relatively low cellular hydrophobicity could be due to a hydrophobic slime that is removed during the suspension and washing procedures. The possibility that specific bacteria assist in fish locomotion by changing the surface properties of the fish skin and by producing drag-reducing polymers is discussed.
Unexpected photoreactivation of Vibrio harveyi bacteria living in ionization environment
DOE Office of Scientific and Technical Information (OSTI.GOV)
Alifano, P.; Tala, A.; Tredici, S. M.
2011-05-15
Bacteria undergoing environmental effects is extremely interesting for structural, mechanistic, and evolutionary implications. Luminescent bacteria that have evolved in a specific ambient have developed particular responses and their behavior can give us new suggestions on the task and production of luciferina proteins. To analyze the UV interaction under controlled laboratory conditions, we used photoluminescent bacterial strains belonging to a new species evolutionarily close to Vibrio harveyi sampled from a coastal cave with a high radon content that generates ionizing radiation. The survival of the bacterial strains was analyzed, in the light and in the dark, following a variety of genotoxicmore » treatments including UV radiation exposure. The strains were irradiated by a germicide lamp. The results demonstrated that most of the strains exhibited a low rate of survival after the UV exposure. After irradiation by visible light following the UV exposure, all strains showed a high capability of photoreactivation when grown. This capability was quite unexpected because these bacteria were sampled from a dark ambient without UV radiation. This leads us to hypothesize that the photoreactivation in these bacteria might have been evolved to repair DNA lesions also induced by different radiation sources other than UV (e.g., x-ray) and that the luminescent bacteria might use their own light emission to carry out the photoreactivation. The high capability of photoreactivation of these bacteria was also justified by the results of deconvolution. The deconvolution was applied to the emission spectra and it was able to show evidence of different light peaks. The presence of the visible peak could control the photolysis enzyme.« less
Selected KSC Applied Physics Lab Responses to Shuttle Processing Measurement Requests
NASA Technical Reports Server (NTRS)
Youngquist, Robert C.
2010-01-01
The KSC Applied Physics Lab has been supporting Shuttle Ground Processing for over 20 years by solving problems brought to us by Shuttle personnel. Roughly half of the requests to our lab have been to find ways to make measurements, or to improve on an existing measurement process. This talk will briefly cover: 1) Centering the aft end of the External Tank between the Solid Rocket Boosters; 2) Positioning the GOX Vent Hood over the External Tank; 3) Remote Measurements of External Tank Damage; 4) Strain Measurement in the Orbiter Sling; and 5) Over-center Distance Measurement in an Over-center Mechanism.
Vázquez, Clotilde; Botella-Carretero, José I; García-Albiach, Raimundo; Pozuelo, María J; Rodríguez-Baños, Mercedes; Baquero, Fernando; Baltadjieva, María A; del Campo, Rosa
2013-01-01
Genetic diversity and resistance of Lactobacillus bulgaricus sbsp. delbrueckii collection with 100 isolates from different home-made yogurt in rural Bulgarian areas were determined. The strain K98 was the most resistant to bile salts and low pH. Survival and effects on short chain fatty acids production were tested in 20 healthy volunteers. High genetic diversity was observed in the L. bulgaricus collection by RAPD, whereas the ability of tolerate high deoxycholic acid concentrations, and different acid pHs was variable. The strain K98 was selected and used to prepare a homemade yogurt which was administered to 20 healthy volunteers (500 ml/day during 15d). A basal faecal sample and another after yogurt intake were recovered. DGGE experiments, using both universal and Lactic Acid Bacteria (LAB) primers, demonstrated no significant changes in the qualitative composition of gut microbiota. A band corresponding to L. bulgaricus was observed in all 20 samples. Viable L. bulgaricus K98 strain was only recovered in one volunteer. After yogurt intake we found an increase of LAB and Clostridium perfringens, and a decrease of Bacteroides- Prevotella-Porphyromonas. In addition, increases of acetic, butyric and 2-hydroxy-butyric acids in faeces were detected. Genetic diversity of L. delbrueckii subsp. bulgaricus especie is high We have isolated a probiotic resistant strain to bile and high acidity, L. delbrueckii subsp. bulgaricus-K98. Qualitative and quantitative changes in the intestinal microbiota are found after ingestion of a homemade yogurt containing this strain, with a concomitant increase in faecal SCFA. Our findings support the interest in developing further studies providing different amounts of L. delbrueckii subsp. bulgaricus-K98, and should evaluate its clinical effects in human disease. Copyright © AULA MEDICA EDICIONES 2013. Published by AULA MEDICA. All rights reserved.
Soltani, Aboozar; Vatandoost, Hassan; Oshaghi, Mohammad Ali; Enayati, Ahmad Ali; Chavshin, Ali Reza
2017-09-01
In the current study, the effects of the presence of symbiotic bacteria on the activity of the enzymes involved in An. stephensi resistance to temephos are evaluated for the first time. Four different strains (I. susceptible strain, II. resistant strain, III. resistant strain + antibiotic, and IV. resistant strain + bacteria) were considered in order to determine the possible effects of the symbiotic bacteria on their hosts' resistance to temephos. The median values of all enzymes of susceptible strain were compared with those of other resistant strains. The results of this study indicated a direct relationship between the presence of bacteria in the symbiotic organs of An. stephensi and resistance to temephos. The profile of enzymatic activities in the resistant strain changed to a susceptible status after adding antibiotic. The resistance of An. stephensi to temephos could be completely broken artificially by removing their bacterial symbionts in a resistant population.
Potential application of algicidal bacteria for improved lipid recovery with specific algae.
Lenneman, Eric M; Wang, Ping; Barney, Brett M
2014-05-01
The utility of specific strains of natural algicidal bacteria isolated from shallow wetland sediments was evaluated against several strains of algae with potential immediate or future commercial value. Two strains of bacteria, Pseudomonas pseudoalcaligenes AD6 and Aeromonas hydrophila AD9, were identified and demonstrated to have algicidal activity against the microalgae Neochloris oleoabundans and Dunaliella tertiolecta. These bacteria were further evaluated for the potential to improve lipid extraction using a mild solvent extraction approach. Aeromonas hydrophila AD9 showed a nearly 12-fold increase in lipid extraction with D. tertiolecta, while both bacteria showed a sixfold improvement in lipid extraction with N. oleoabundans. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.
Muñoz, R; Arena, M.E.; Silva, J.; González, S.N.
2010-01-01
The effect of different fermenting microorganisms on growth of a mycotoxin- producing Aspergillus nomius was assayed. Two lactic acid bacteria, Lactobacillus fermentum and Lactobacillus rhamnosus, and Saccharomyces cerevisiae, all of which are widely used in fermentation and preservation of food, were assayed on their fungus inhibitory properties. Assays were carried out by simultaneous inoculation of one of the possible inhibiting microorganisms and the fungus or subsequent inoculation of one of the microorganisms followed by the fungus. All three microorganisms assayed showed growth inhibition of the mycotoxin-producing Aspergillus strain. L. rhamnosus O236, isolated from sheep milk and selected for its technological properties, showed highest fungal inhibition of the microorganisms assayed. The use of antifungal LAB with excellent technological properties rather than chemical preservatives would enable the food industry to produce organic food without addition of chemical substances. PMID:24031582
Muñoz, R; Arena, M E; Silva, J; González, S N
2010-10-01
The effect of different fermenting microorganisms on growth of a mycotoxin- producing Aspergillus nomius was assayed. Two lactic acid bacteria, Lactobacillus fermentum and Lactobacillus rhamnosus, and Saccharomyces cerevisiae, all of which are widely used in fermentation and preservation of food, were assayed on their fungus inhibitory properties. Assays were carried out by simultaneous inoculation of one of the possible inhibiting microorganisms and the fungus or subsequent inoculation of one of the microorganisms followed by the fungus. All three microorganisms assayed showed growth inhibition of the mycotoxin-producing Aspergillus strain. L. rhamnosus O236, isolated from sheep milk and selected for its technological properties, showed highest fungal inhibition of the microorganisms assayed. The use of antifungal LAB with excellent technological properties rather than chemical preservatives would enable the food industry to produce organic food without addition of chemical substances.
Cui, J; Xiao, M; Liu, M; Wang, Z; Liu, F; Guo, L; Meng, H; Zhang, H; Yang, J; Deng, D; Huang, S; Ma, Y; Liu, C
2017-11-01
To demonstrate a nonempirical workflow to select host-specific probiotics for aquaculture industry. Using both culture-dependent and culture-independent methods, we have systematically investigated, for the first time, the gut microbiota of twelve subtropical aquatic animal species. We found that the diversity, abundance and distribution of gut micro-organisms of these animals were host-specific and that lactic acid bacteria (LAB) were predominant among the indigenous probiotic microbes. Using culturing method, we isolated and characterized ninety-eight LAB strains; however, only a few strains was representative of the dominant LAB OTUs recovered by culture-independent analysis. Two cultured LAB strains, Enterococcus faecalis LS1-2 and Enterococcus faecium Z1-2, capturing the major LAB OTUs in the sequencing data set of the most animal samples and showing significant antimicrobial activities against shrimp pathogens, were suggested to be the candidates of shrimp probiotics. Disease outbreak and the consequential abuse of antibiotics have been the constraints to the aquaculture industry. However, the selection of probiotic bacteria is currently still an empirical process due to our limited knowledge on the gastrointestinal microbiota of aquatic organisms. Our study points to a nonempirical selection process by which host-specific probiotics can be developed. © 2017 The Society for Applied Microbiology.
Lee, WonWoo; Oh, Jae Young; Kim, Eun-A; Kang, Nalae; Kim, Kil-Nam; Ahn, Ginnae; Jeon, You-Jin
2016-07-01
In this study, the beneficial prebiotic roles of Ecklonia cava (E. cava, EC) were evaluated on the growth of lactic acid bacteria (LAB) and pathogen bacteria and the mortality of pathogen-bacteria infected zebrafish model. The result showed that the original E. cava (EC) led to the highest growth effects on three LABs (Lactobacillus brevis, L. brevis; Lactobacillus pentosus, L. pentosus; Lactobacillus plantarum; L. plantarum) and it was dose-dependent manners. Also, EC, its Celluclast enzymatic (ECC) and 100% ethanol extracts (ECE) showed the anti-bacterial activities on the fish pathogenic bacteria such as (Edwardsiella tarda; E. tarda, Streptococcus iniae; S. iniae, and Vibrio harveyi; V. harveyi). Interestingly, EC induced the higher production of the secondary metabolites from L. plantarum in MRS medium. The secondary metabolites produced by EC significantly inhibited the growth of pathogen bacteria. In further in vivo study, the co-treatment of EC and L. plantarum improved the growth and mortality of E. tarda-infected zebrafish as regulating the expression of inflammatory molecules such as iNOS and COX2. Taken together, our present study suggests that the EC plays an important role as a potential prebiotic and has a protective effect against the infection caused by E. tarda injection in zebrafish. Also, our conclusion from this evidence is that EC can be used and applied as a useful prebiotic. Copyright © 2016 Elsevier Ltd. All rights reserved.
Antibiotic-producing bacteria from stag beetle mycangia.
Miyashita, Atsushi; Hirai, Yuuki; Sekimizu, Kazuhisa; Kaito, Chikara
2015-02-01
The search for new antibiotics or antifungal agents is crucial for the chemotherapies of infectious diseases. The limited resource of soil bacteria makes it difficult to discover such new drug candidate. We, therefore, focused on another bacterial resource than soil bacteria, the microbial flora of insect species. In the present study, we isolated 40 strains of bacteria and fungi from the mycangia of three species of stag beetle, Dorcus hopei binodulosus, Dorcus rectus, and Dorcus titanus pilifer. We identified those species with their ribosomal DNA sequences, and revealed that Klebsiella spp. are the most frequent symbiont in the stag beetle mycangia. We examined whether these microorganisms produce antibiotics against a Gram-negative bacterium, Escherichia coli, a Gram-positive bacterium, Staphylococcus aureus, or a fungus, Cryptococcus neoformans. Culture supernatants from 33, 29, or 18 strains showed antimicrobial activity against E. coli, S. aureus, or C. neoformans, respectively. These findings suggest that bacteria present in the mycangia of stag beetles are useful resources for screening novel antibiotics.
Kwaw, Emmanuel; Ma, Yongkun; Tchabo, William; Apaliya, Maurice Tibiru; Wu, Meng; Sackey, Augustina Sackle; Xiao, Lulu; Tahir, Haroon Elrasheid
2018-06-01
This study was conducted to investigate the effect of lactic acid bacteria (LAB) strains on color properties, phenolic profile and antioxidant activities of mulberry juice. Mulberry juice was separately fermented at 37 °C for 36 h using Lactobacillus plantarum, Lactobacillus acidophilus and Lactobacillus paracasei. The results showed that lactic acid fermentation impacted on the color of the juice. Moreover, the study demonstrated that LABs impacted on the phenolic profile of the juice. Syringic acid, cyanidin-3-O-rutinoside and quercetin were the predominant phenolic acid, anthocyanin and flavonol respectively in the lactic-acid-fermented mulberry juice. The degree of radical scavenging activity was species-specific with the L. plantarum fermented juice having the highest radical scavenging activities. The correlation analysis demonstrated that flavonols and anthocyanins were mostly responsible for the increased in 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) scavenging activity while phenolic acids and flavonols were responsible for 2,2-diphenyl-1-picrylhydrazyl scavenging activity and reducing power capacity of the fermented juice. Copyright © 2018 Elsevier Ltd. All rights reserved.
Terzic-Vidojevic, Amarela; Mihajlovic, Sanja; Uzelac, Gordana; Veljovic, Katarina; Tolinacki, Maja; Nikolic, Milica; Topisirovic, Ljubisa; Kojic, Milan
2014-05-01
The aim of this study was to investigate the composition of lactic acid bacteria (LAB) in autochthonous young cheeses, sweet creams and sweet kajmaks produced in the Vlašić mountain region of central Bosnia and Herzegovina near the town of Travnik over a four season period. These three products were made from cow's milk by a traditional method without the addition of a starter culture. Preliminary characterization with phenotype-based assays and identification using rep-PCR with a (GTG)5 primer and 16S rDNA sequence analysis were undertaken for 460 LAB isolates obtained from all the examined samples. Fifteen species were identified as follows: Lactococcus lactis, Lactococcus raffinolactis, Lactococcus garviae, Lactobacillus casei, Lactobacillus plantarum, Lactobacillus helveticus, Enterococcus faecium, Enterococcus durans, Enterococcus faecalis, Enterococcus italicus, Leuconostoc mesenteroides, Leuconostoc pseudomesenteroides, Leuconostoc lactis, Streptococcus thermophilus and Streptococcus mitis. A wide genotypic and phenotypic heterogeneity of the species was observed, particularly within the Lc. lactis strains. In all of the tested dairy products across four seasons, a significantly positive correlation (r = 0.690) between the presence of lactococci and enterococci and a negative correlation (r = 0.722) between the presence of lactococci and leuconostocs were recorded. Forty-five percent of the lactobacilli and 54.4% of the lactococci exhibited proteolytic activity, whereas 18.7% of the total LAB isolates exhibited antimicrobial activity. Copyright © 2013 Elsevier Ltd. All rights reserved.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Mahony, Jennifer, E-mail: j.mahony@ucc.ie; Ainsworth, Stuart; Stockdale, Stephen
Dairy fermentations are among the oldest food processing applications, aimed at preservation and shelf-life extension through the use of lactic acid bacteria (LAB) starter cultures, in particular strains of Lactococcus lactis, Streptococcus thermophilus, Lactobacillus spp. and Leuconostoc spp. Traditionally this was performed by continuous passaging of undefined cultures from a finished fermentation to initiate the next fermentation. More recently, consumer demands on consistent and desired flavours and textures of dairy products have led to a more defined approach to such processes. Dairy (starter) companies have responded to the need to define the nature and complexity of the starter culture mixes,more » and dairy fermentations are now frequently based on defined starter cultures of low complexity, where each starter component imparts specific technological properties that are desirable to the product. Both mixed and defined starter culture approaches create the perfect environment for the proliferation of (bacterio)phages capable of infecting these LAB. The repeated use of the same starter cultures in a single plant, coupled to the drive towards higher and consistent production levels, increases the risk and negative impact of phage infection. In this review we will discuss recent advances in tracking the adaptation of phages to the dairy industry, the advances in understanding LAB phage-host interactions, including evolutionary and genomic aspects.« less
Castellano, Patricia; Pérez Ibarreche, Mariana; Fontana, Cecilia; Vignolo, Graciela M.
2017-01-01
The globalization of trade and lifestyle ensure that the factors responsible for the emergence of diseases are more present than ever. Despite biotechnology advancements, meat-based foods are still under scrutiny because of the presence of pathogens, which causes a loss of consumer confidence and consequently a fall in demand. In this context, Lactic Acid Bacteria (LAB) as GRAS organisms offer an alternative for developing pathogen-free foods, particularly avoiding Listeria monocytogenes, with minimal processing and fewer additives while maintaining the foods’ sensorial characteristics. The use of LAB strains, enabling us to produce antimicrobial peptides (bacteriocins) in addition to lactic acid, with an impact on quality and safety during fermentation, processing, and/or storage of meat and ready-to-eat (RTE) meat products, constitutes a promising tool. A number of bacteriocin-based strategies including the use of bioprotective cultures, purified and/or semi-purified bacteriocins as well as their inclusion in varied packaging materials under different storage conditions, have been investigated. The application of bacteriocins as part of hurdle technology using non-thermal technologies was explored for the preservation of RTE meat products. Likewise, considering that food contamination with L. monocytogenes is a consequence of the post-processing manipulation of RTE foods, the role of bacteriocinogenic LAB in the control of biofilms formed on industrial surfaces is also discussed. PMID:28696370
Gómez-Sala, Beatriz; Herranz, Carmen; Díaz-Freitas, Belén; Hernández, Pablo E; Sala, Ana; Cintas, Luis M
2016-04-16
In this work we describe the development of a biopreservation strategy for fresh fish based on the use of bacteriocinogenic LAB of marine origin. For this purpose, two multibacteriocinogenic LAB strains, Lactobacillus curvatus BCS35 and Enterococcus faecium BNM58, previously isolated from fish and fish products were selected owing to their capability to inhibit the growth of several fish-spoilage and food-borne pathogenic bacteria. Two commercially important fish species were chosen, young hake (Merluccius merluccius) and megrim (Lepidorhombus boscii), and the specimens were acquired at the Marín (Pontevedra, Spain) retail fish market, after one night in the chilled hold of a near-shore fishing vessel. The biopreservation potential and the application strategies of these two LAB strains were first tested at a laboratory scale, where several batches of fresh fish were inoculated with: (i) the multibacteriocinogenic LAB culture(s) as protective culture(s); and/or (ii) their cell-free culture supernatant(s) as food ingredient(s), and (iii) the lyophilized bacteriocin preparation(s) as lyophilized food ingredient(s). All batches were stored in polystyrene boxes, permanently filled with ice at 0-2 °C, for 14 days. Microbiological analyses, as well as sensorial analyses, were carried out during the biopreservation trials. Subsequently, Lb. curvatus BCS35 was selected to up-scale the trials, and combinations of the three application methods were assayed. For this purpose, this strain was grown in a semi-industrial scale fermentor (150l) in modified MRS broth, and three batches of fresh fish were inoculated with the protective culture and/or food ingredient, and stored on ice in a chilled chamber at 0-2 °C at the Marín retail fish market for 14 days. Microbiological analyses were carried out during the storage period, showing that when Lb. curvatus BCS35 culture or the corresponding cell-free culture supernatant was used as protective culture or food ingredient
Discrimination of wine lactic acid bacteria by Raman spectroscopy.
Rodriguez, Susan B; Thornton, Mark A; Thornton, Roy J
2017-08-01
Species of Lactobacillus, Pediococcus, Oenococcus, and Leuconostoc play an important role in winemaking, as either inoculants or contaminants. The metabolic products of these lactic acid bacteria have considerable effects on the flavor, aroma, and texture of a wine. However, analysis of a wine's microflora, especially the bacteria, is rarely done unless spoilage becomes evident, and identification at the species or strain level is uncommon as the methods required are technically difficult and expensive. In this work, we used Raman spectral fingerprints to discriminate 19 strains of Lactobacillus, Pediococcus, and Oenococcus. Species of Lactobacillus and Pediococcus and strains of O. oeni and P. damnosus were classified with high sensitivity: 86-90 and 84-85%, respectively. Our results demonstrate that a simple, inexpensive method utilizing Raman spectroscopy can be used to accurately identify lactic acid bacteria isolated from wine.
Doan, N T L; Van Hoorde, K; Cnockaert, M; De Brandt, E; Aerts, M; Le Thanh, B; Vandamme, P
2012-10-01
To evaluate the potential use of MALDI-TOF MS for fast and reliable classification and identification of lactic acid bacteria (LAB) from traditional fermented foods. A total of 119 strains of LAB from fermented meat (nem chua) were analysed with both (GTG)(5)-PCR fingerprinting and MALDI-TOF MS. Cluster analysis of the profiles revealed five species represented by a single isolate both in (GTG)(5)-PCR and in MALDI-TOF MS; five species grouped alike for (GTG)(5)-PCR and for MALDI-TOF MS; however, differences in minimal similarity between the delineated (GTG)(5)-PCR and MALDI-TOF MS clusters could be observed; three species showed more heterogeneity in their MALDI-TOF MS profiles compared to their (GTG)(5)-PCR profiles; two species, each represented by a single MALDI-TOF cluster, were subdivided in the corresponding (GTG)(5)-PCR dendrogram. As proof of the identification potential of MALDI-TOF MS, LAB diversity from one fermented mustard sample was analysed using MALDI-TOF MS. PheS gene sequencing was used for validation. MALDI-TOF MS is a powerful, fast, reliable and cost-effective technique for the identification of LAB associated with the production of fermented foods. Food LAB can be identified using MALDI-TOF MS, and its application could possibly be extended to other food matrices and/or other food-derived micro-organisms. © 2012 The Authors. Letters in Applied Microbiology © 2012 The Society for Applied Microbiology.
Monteagudo-Mera, A; Caro, I; Rodríguez-Aparicio, L B; Rúa, J; Ferrero, M A; García-Armesto, M R
2011-08-01
The present work was aimed at characterizing 12 strains of lactic acid bacteria (LAB) to obtain improved potential starter or probiotic cultures that could be used for making dairy products from ewe's milk and cow's milk. Eight strains with antimicrobial properties, isolated from ewe's milk and from cheese made from ewe's and/or cow's milk, were studied. They were identified as Enterococcus faecalis (five strains), Lactococcus lactis subsp. cremoris, Leuconostoc mesenteroides, and Lactobacillus paracasei subsp. paracasei (one strain of each species). Additionally, four strains were obtained from the American Type Culture Collection: Lactobacillus casei 393 (isolated from cheese), L. lactis subsp. lactis 11454 (origin nonspecified and a producer of nisin), and two strains isolated from human feces (L. paracasei subsp. paracasei 27092 and Lactobacillus rhamnosus 53103, antibacterial agent producer). All E. faecalis strains showed at least one virulence factor (either hemolysin or gelatinase), which emphasizes the importance of these studies in this species. Both L. lactis strains and most Lactobacillus spp. were good acidifiers in ewe's milk and cow's milk at 30°C. High β-galactosidase activity, as well as aminopeptidase activities that favor the development of desirable flavors in cheese, were detected in all Lactobacillus spp. strains. Furthermore, L. rhamnosus ATCC 53103 showed α-fucosidase activity (thought to help colonization of the intestine) and lack of α-glucosidase activity (a trait considered positive for diabetic and obese humans). This last enzymatic activity was also lacking in L. lactis ATCC 11454. L. mesenteroides was the only strain D(2)-lactic acid producer. The selection of any particular strain for probiotic or dairy cultures should be performed according to the technological and/or functional abilities needed.
de la Fuente-Salcido, Norma M; Castañeda-Ramírez, José Cristobal; García-Almendárez, Blanca E; Bideshi, Dennis K; Salcedo-Hernández, Rubén; Barboza-Corona, José E
2015-01-01
Mexican Tuba (M-Tuba) and Tepache are Mexican fermented beverages prepared mainly with pineapple pulp and coconut palm, respectively. At present, reports on the microbiota and nutritional effects of both beverages are lacking. The purpose of this study was to determine whether M-Tuba and Tepache contain cultivable lactic acid bacteria (LAB) capable of producing bacteriocins. Tepache and M-Tuba contain mesophilic aerobic bacteria, LAB, and yeast. Bacillus subtilis, Listeria monocytogenes, Listeria innocua, Streptococcus agalactiae, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Salmonella typhimurium, and Salmonella spp, were the microorganisms most susceptible to metabolites produced by bacterial isolates. M-Tuba and Tepache contain bacteria that harbor genes coding for nisin and enterocin, but not pediocin. The presence of Lactococcus lactis and E. faecium in M-Tuba and Tepache, was identified by 16S rDNA. These bacteria produced bacteriocins of ∼3.5 kDa and 4.0–4.5 kDa, respectively. Partial purified bacteriocins showed inhibitory effect against Micrococcus luteus, L. monocytogenes, L. innocua, Str. agalactiae, S. aureus, Bacillus cereus, B. subtilis, E. faecalis, and K. pneumoniae. We characterized, for the first time, cultivable microbiota of M-Tuba and Tepache, and specifically, identified candidate lactic bacteria (LAB) present in these beverages that were capable of synthesizing antimicrobial peptides, which collectively could provide food preservative functions. PMID:26405529
NASA Astrophysics Data System (ADS)
Tang, Yali; Cheng, Dongmei; Guan, Baohua; Zhang, Xiufeng; Liu, Zhengwen; Liu, Zejun
2017-05-01
Bacteria capable of degrading cyanobacteria Microcystis are crucial for determining the ecological consequences of Microcystis blooms in freshwater lakes. Scum derived from Microcystis blooms tends to accumulate in bays of large lakes and then sink to the sediments where it is finally consumed by benthic bacteria. Understanding the response of benthic bacterial communities to massive Microcystis deposition events may help identify the bacteria best suited to Microcystis hydrolyzation and even bloom control. For that purpose, an experimental system was set up in which intact sediment cores were incubated in the laboratory with normal and heavy deposits of Microcystis detritus. Pyrosequencing was performed in order to describe a phylogenetic inventory of bacterial communities in samples taken at 0-1, 1-2 and 2-3 cm depths in incubated sediments and in original untreated sediment. A hierarchical cluster tree was constructed expose differences between sediments. Similarity percentage calculations were also performed to identify the bacterial species contributing to variation. The results of this study suggest that: (1) deposition of Microcystis scums exerts a strong effect on the bacterial community composition in the surface (0-1 cm) and sub-surface (1-2 cm) sediment layers; (2) bacterial community responses to Microcystis detritus deposition vary across vertical gradients. A list of bacteria with potential roles in Microcystis degradation was compiled. These findings may inform the development of future measures for Microcystis bloom control in lakes.
Lee, Do Kyung; Jang, Seok; Baek, Eun Hye; Kim, Mi Jin; Lee, Kyung Soon; Shin, Hea Soon; Chung, Myung Jun; Kim, Jin Eung; Lee, Kang Oh; Ha, Nam Joo
2009-06-11
Lactic acid bacteria (LAB) are beneficial probiotic organisms that contribute to improved nutrition, microbial balance, and immuno-enhancement of the intestinal tract, as well as lower cholesterol. Although present in many foods, most trials have been in spreads or dairy products. Here we tested whether Bifidobacteria isolates could lower cholesterol, inhibit harmful enzyme activities, and control fecal water content. In vitro culture experiments were performed to evaluate the ability of Bifidobacterium spp. isolated from healthy Koreans (20 approximately 30 years old) to reduce cholesterol-levels in MRS broth containing polyoxyethanylcholesterol sebacate. Animal experiments were performed to investigate the effects on lowering cholesterol, inhibiting harmful enzyme activities, and controlling fecal water content. For animal studies, 0.2 ml of the selected strain cultures (108 approximately 109 CFU/ml) were orally administered to SD rats (fed a high-cholesterol diet) every day for 2 weeks. B. longum SPM1207 reduced serum total cholesterol and LDL levels significantly (p < 0.05), and slightly increased serum HDL. B. longum SPM1207 also increased fecal LAB levels and fecal water content, and reduced body weight and harmful intestinal enzyme activities. Daily consumption of B. longum SPM1207 can help in managing mild to moderate hypercholesterolemia, with potential to improve human health by helping to prevent colon cancer and constipation.
McNeely, Damian; Chanyi, Ryan M; Dooley, James S; Moore, John E; Koval, Susan F
2017-04-01
Bdellovibrio and like organisms are predatory bacteria that have the unusual property of using the cytoplasmic constituents of other Gram-negative bacteria as nutrients. These predators may thus provide an alternative approach to the biocontrol of human and plant pathogens. Predators were isolated on Burkholderia cenocepacia K56-2 and J2315 as prey cells, in enrichment cultures with soil and sewage. Three isolates (DM7C, DM8A, and DM11A) were identified as Bdellovibrio bacteriovorus on the basis of morphology, a periplasmic life cycle, and 16S rRNA gene sequencing. The prey range of these isolates was tested on Burkholderia cepacia complex bacteria and several phytopathogenic bacteria of agricultural importance. Of 31 strains of the Burkholderia cepacia complex tested, only 4 were resistant to predation by strain DM7C. A subset of 9 of the prey tested were also susceptible to strains DM8A and DM11A. Of 12 phytopathogens tested, 4 were resistant to strains DM7C and DM8A, and only 2 were resistant to strain DM11A. Thus, Bdellovibrio bacteriovorus strains retrieved from environmental samples on 2 Burkholderia cenocepacia isolates from cystic fibrosis patients did not distinguish in their prey range between other isolates of that pathogen or phytopathogens. Such strains hold promise as potential wide-spectrum biocontrol agents.
Kim, Sung Hwan; Jeung, Woonhee; Choi, Il-Dong; Jeong, Ji-Woong; Lee, Dong Eun; Huh, Chul-Sung; Kim, Geun-Bae; Hong, Seong Soo; Shim, Jae-Jung; Lee, Jung Lyoul; Sim, Jae-Hun; Ahn, Young-Tae
2016-06-28
To evaluate the effects of lactic acid bacteria (LAB) on Peyer's patch cells, mice were treated with a high dose of kanamycin to disturb the gut microbial environment. The overarching goal was to explore the potential of LAB for use as a dietary probiotic that buffers the negative consequences of antibiotic treatment. In vitro, LAB stimulated the production of immunoglobulin A (IgA) from isolated Peyer's patch cells. Inflammation-related genes (TNF-α, IL-1β, and IL-8) were up-regulated in Caco-2 cells stimulated with lipopolysaccharide (LPS), while tight-junction-related genes (ZO-1 and occludin) were down-regulated; the effects of LPS on inflammatory gene and tight-junction gene expression were reversed by treatment with LAB. Mice treated with a high dose of kanamycin showed increased serum IgE levels and decreases in serum IgA and fecal IgA levels; the number of Peyer's patch cells decreased with kanamycin treatment. However, subsequent LAB treatment was effective in reducing the serum IgE level and recovering the serum IgA and fecal IgA levels, as well as the number of Peyer's patch cells. In addition, ZO-1 and occludin mRNA levels were up-regulated in the ileum tissues of mice receiving LAB treatment. Lactic acid bacteria can enhance the intestinal immune system by improving the integrity of the intestinal barrier and increasing the production of IgA in Peyer's patches. Lactic acid bacteria should be considered a potential probiotic candidate for improving intestinal immunity, particularly in mitigating the negative consequences of antibiotic use.
Feng, Cuijie; Li, Jiangwei; Qin, Dan; Chen, Lixiang; Zhao, Feng; Chen, Shaohua; Hu, Hongbo; Yu, Chang-Ping
2014-01-01
Microorganisms capable of generating electricity in microbial fuel cells (MFCs) have gained increasing interest. Here fourteen exoelectrogenic bacterial strains were isolated from the anodic biofilm in an MFC before and after copper (Cu) shock load by Hungate roll-tube technique with solid ferric (III) oxide as an electron acceptor and acetate as an electron donor. Phylogenetic analysis of the 16S rRNA gene sequences revealed that they were all closely related to Enterobacter ludwigii DSM 16688T within the Enterobacteriaceae family, although these isolated bacteria showed slightly different morphology before and after Cu shock load. Two representative strains R2B1 (before Cu shock load) and B4B2 (after Cu shock load) were chosen for further analysis. B4B2 is resistant to 200 mg L−1 of Cu(II) while R2B1 is not, which indicated the potential selection of the Cu shock load. Raman analysis revealed that both R2B1 and B4B2 contained c-type cytochromes. Cyclic voltammetry measurements revealed that strain R2B1 had the capacity to transfer electrons to electrodes. The experimental results demonstrated that strain R2B1 was capable of utilizing a wide range of substrates, including Luria-Bertani (LB) broth, cellulose, acetate, citrate, glucose, sucrose, glycerol and lactose to generate electricity, with the highest current density of 440 mA·m−2 generated from LB-fed MFC. Further experiments indicated that the bacterial cell density had potential correlation with the current density. PMID:25412475
Grünberger, Alexander; Paczia, Nicole; Probst, Christopher; Schendzielorz, Georg; Eggeling, Lothar; Noack, Stephan; Wiechert, Wolfgang; Kohlheyer, Dietrich
2012-05-08
In the continuously growing field of industrial biotechnology the scale-up from lab to industrial scale is still a major hurdle to develop competitive bioprocesses. During scale-up the productivity of single cells might be affected by bioreactor inhomogeneity and population heterogeneity. Currently, these complex interactions are difficult to investigate. In this report, design, fabrication and operation of a disposable picolitre cultivation system is described, in which environmental conditions can be well controlled on a short time scale and bacterial microcolony growth experiments can be observed by time-lapse microscopy. Three exemplary investigations will be discussed emphasizing the applicability and versatility of the device. Growth and analysis of industrially relevant bacteria with single cell resolution (in particular Escherichia coli and Corynebacterium glutamicum) starting from one single mother cell to densely packed cultures is demonstrated. Applying the picolitre bioreactor, 1.5-fold increased growth rates of C. glutamicum wild type cells were observed compared to typical 1 litre lab-scale batch cultivation. Moreover, the device was used to analyse and quantify the morphological changes of an industrially relevant l-lysine producer C. glutamicum after artificially inducing starvation conditions. Instead of a one week lab-scale experiment, only 1 h was sufficient to reveal the same information. Furthermore, time lapse microscopy during 24 h picolitre cultivation of an arginine producing strain containing a genetically encoded fluorescence sensor disclosed time dependent single cell productivity and growth, which was not possible with conventional methods.
Detection of heavy metal resistance bioluminescence bacteria using microplate bioassay method.
Ranjitha, P; Karthy, E S
2012-01-01
Effects of different heavy metals on Vibrio harveyi, V. fischeri, Photobacterium phosphoreum and P. leiognathi were examined. Checkerboard assay was used for the detection of the natural metal tolerance levels of a large number of marine luminous eubacteria. 57 strains of luminous bacteria were investigated for their natural patterns of heavy metal tolerance. The behaviors of these strains were not homogeneous with respect to all metals tested, even within the strains belonging to the same genus. At least 1 to 4 different MICs were detected for every metal except barium and cobalt. Isolated bacteria were tested for the presence of plasmids using the modified alkaline lysis method, was effective for identification of plasmids of different sizes. This study revealed the frequency of the occurrence of plasmids in heavy metal resistance bacteria and inferred that plasmids are highly ubiquitous and predominant in most heavy metal resistant bacteria.
NASA Astrophysics Data System (ADS)
Sari, Melia; Suryanto, Dwi; Yurnaliza
2018-03-01
Bekasam is an Indonesian fermented food made of fish. As a fermented food, this food may contain some beneficial bacteria like lactic acid bacteria (LAB), which usually have antimicrobial properties such as organic acid, hydrogen peroxide, and a bacteriocin. A study on antimicrobial activity of LAB isolated from bekasam against some pathogenic bacteria has been conducted. The purpose of this study was to know the ability of crude bacteriocin produced LAB of bekasam against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Salmonella sp. Bekasam sample was taken from South Sumatera. LAB isolation was done using de Man Rogosa and Sharpe agar. A bacterial colony with clear zone was selected and purified to get a single colony. The antagonistic assay of the LAB was conducted in Muller-Hinton agar Selected isolates with higher clearing zone were assayed for antibacterial effect of their crude bacteriocin of different culture incubation time of 6, 9, and 12 hours. The results showed that the crude extract bacteriocin of isolate MS2 of 9 hours culture incubation time inhibited more in Staphylococcus aureus ATCC 25923 with inhibition zone of 13.1 mm, whereas isolate MS9 of 9 hours culture incubation time inhibited more in Escherichia coli ATCC 25922 and Salmonella sp. with inhibition zone of 12.7 and 7.3 mm, respectively.
Diversity and distribution of culturable lactic acid bacterial species in Indonesian Sayur Asin
Mangunwardoyo, Wibowo; Abinawanto; Salamah, Andi; Sukara, Endang; Sulistiani; Dinoto, Achmad
2016-01-01
Background and Objectives: Lactic acid bacteria (LAB) play important roles in processing of Sayur Asin (spontaneously fermented mustard). Unfortunately, information about LAB in Indonesian Sayur Asin, prepared by traditional manufactures which is important as baseline data for maintenance of food quality and safety, is unclear. The aim of this study was to describe the diversity and distribution of culturable lactic acid bacteria in Sayur Asin of Indonesia. Materials and Methods: Four Sayur Asin samples (fermentation liquor and fermented mustard) were collected at harvesting times (3–7 days after fermentation) from two traditional manufactures in Tulung Agung (TA) and Kediri (KDR), East Java provinces, Indonesia. LAB strains were isolated by using MRS agar method supplemented with 1% CaCO 3 and characterized morphologically. Identification of the strains was performed basedon 16S rDNA analysis and the phylogenetic tree was drawn to understand the phylogenetic relationship of the collected strains. Results: Different profiles were detected in total count of the plates, salinity and pH of fermenting liquor of Sayur Asin in TA and KDR provinces. A total of 172 LAB isolates were successfully isolated and identified based on their 16S rDNA sequences. Phylogenetic analysis of 27 representative LAB strains from Sayur Asin showed that these strains belonged to 5 distinct species namely Lactobacilus farciminis (N=32), L. fermentum (N=4), L. namurensis (N=15), L. plantarum (N=118) and L. parafarraginis (N=1). Strains D5-S-2013 and B4-S-2013 showed a close phylogenetic relationship with L. composti and L. paralimentarius, respectively where as the sequence had slightly lower similarity of lower than 99%, suggesting that they may be classified into novel species and need further investigation due to exhibition of significant differences in their nucleotide sequences. Lactobacillus plantarum was found being dominant in all sayur asin samples. Conclusion: Lactobacilli were
Contribution of increased mutagenesis to the evolution of pollutants-degrading indigenous bacteria
Ilmjärv, Tanel; Naanuri, Eve; Kivisaar, Maia
2017-01-01
Bacteria can rapidly evolve mechanisms allowing them to use toxic environmental pollutants as a carbon source. In the current study we examined whether the survival and evolution of indigenous bacteria with the capacity to degrade organic pollutants could be connected with increased mutation frequency. The presence of constitutive and transient mutators was monitored among 53 pollutants-degrading indigenous bacterial strains. Only two strains expressed a moderate mutator phenotype and six were hypomutators, which implies that constitutively increased mutability has not been prevalent in the evolution of pollutants degrading bacteria. At the same time, a large proportion of the studied indigenous strains exhibited UV-irradiation-induced mutagenesis, indicating that these strains possess error-prone DNA polymerases which could elevate mutation frequency transiently under the conditions of DNA damage. A closer inspection of two Pseudomonas fluorescens strains PC20 and PC24 revealed that they harbour genes for ImuC (DnaE2) and more than one copy of genes for Pol V. Our results also revealed that availability of other nutrients in addition to aromatic pollutants in the growth environment of bacteria affects mutagenic effects of aromatic compounds. These results also implied that mutagenicity might be affected by a factor of how long bacteria have evolved to use a particular pollutant as a carbon source. PMID:28777807
Growth of probiotic bacteria and bifidobacteria in a soy yogurt formulation.
Farnworth, E R; Mainville, I; Desjardins, M-P; Gardner, N; Fliss, I; Champagne, C
2007-05-01
Soy beverage and cows' milk yogurts were produced with Steptococcus thermophilus (ATCC 4356) and Lactobacillus delbrueckii subsp. bulgaricus (IM 025). The drop in pH during fermentation was faster in the soy beverage than in cows' milk, but the final pH values were similar. Yogurts were prepared with a yogurt starter in conjunction with either the probiotic bacteria Lactobacillus johnsonii NCC533 (La-1), Lactobacillus rhamnosus ATCC 53103 (GG) or human derived bifidobacteria. The presence of the probiotic bacteria did not affect the growth of the yogurt strains. Approximately 2 log increases in both L. rhamnosus GG and L. johnsonii La-1 were observed when each was added with the yogurt strains in both cows' milk and the soy beverage. Two of the five bifidobacteria strains grew well in the cows' milk and soy beverage during fermentation with the yogurt bacteria. High pressure liquid chromatography (HPLC) analyses showed that the probiotic bacteria and the bifidobacteria were using different sugars to support their growth, depending on whether the bacteria were growing in cows' milk or soy beverage.
Merckoll, Patricia; Jonassen, Tom Øystein; Vad, Marie Elisabeth; Jeansson, Stig L; Melby, Kjetil K
2009-01-01
Chronically infected wounds are a costly source of suffering. An important factor in the failure of a sore to heal is the presence of multiple species of bacteria, living cooperatively in highly organized biofilms. The biofilm protects the bacteria from antibiotic therapy and the patient's immune response. Honey has been used as a wound treatment for millennia. The components responsible for its antibacterial properties are now being elucidated. The study aimed to determine the effects of different concentrations of 'Medihoney' therapeutic honey and Norwegian Forest Honey 1) on the real-time growth of typical chronic wound bacteria; 2) on biofilm formation; and 3) on the same bacteria already embedded in biofilm. Reference strains of MRSE, MRSA, ESBL Klebsiella pneumoniae and Pseudomonas aeruginosa were incubated with dilution series of the honeys in microtitre plates for 20 h. Growth of the bacteria was assessed by measuring optical density every 10 min. Growth curves, biofilm formation and minimum bactericidal concentrations are presented. Both honeys were bactericidal against all the strains of bacteria. Biofilm was penetrated by biocidal substances in honey. Reintroduction of honey as a conventional wound treatment may help improve individual wound care, prevent invasive infections, eliminate colonization, interrupt outbreaks and thereby preserve current antibiotic stocks.
Carvalho, B F; Ávila, C L S; Bernardes, T F; Pereira, M N; Santos, C; Schwan, R F
2017-03-01
The aim of this study was to evaluate the chemical and microbiological characteristics and to identify the lactic acid bacteria (LAB) and yeasts involved in rehydrated corn kernel silage. Four replicates for each fermentation time: 5, 15, 30, 60, 90, 150, 210 and 280 days were prepared. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and PCR-based identification were utilized to identify LAB and yeasts. Eighteen bacteria and four yeast species were identified. The bacteria population reached maximum growth after 15 days and moulds were detected up to this time. The highest dry matter (DM) loss was 7·6% after 280 days. The low concentration of water-soluble carbohydrates (20 g kg -1 of DM) was not limiting for fermentation, although the reduction in pH and acid production occurred slowly. Storage of the rehydrated corn kernel silage increased digestibility up to day 280. This silage was dominated by LAB but showed a slow decrease in pH values. This technique of corn storage on farms increased the DM digestibility. This study was the first to evaluate the rehydrated corn kernel silage fermentation dynamics and our findings are relevant to optimization of this silage fermentation. © 2016 The Society for Applied Microbiology.
Xie, Wen; Liu, Yang; Wang, Shaoli; Wu, Qingjun; Pan, Huipeng; Yang, Xin; Guo, Litao; Zhang, Youjun
2014-01-01
Abstract Whitefly biotypes B and Q are the two most damaging members of the Bemisia tabaci (Hemiptera: Aleyrodidae) species complex. Control of B. tabaci (and especially of Q) has been impaired by resistance to commonly used insecticides. To find new insecticides for B. tabaci management in China, we investigated the sensitivity of eggs, larvae, and adults of laboratory strains of B and Q (named Lab-B and Lab-Q) and field strains of Q to several insecticides. For eggs, larvae, and adults of B. tabaci and for six insecticides (cyantraniliprole, chlorantraniliprole, pyriproxyfen, buprofezin, acetamiprid, and thiamethoxam), LC 50 values were higher for Lab-Q than for Lab-B; avermectin LC 50 values, however, were low for adults of both Lab-Q and Lab-B. Based on the laboratory results, insecticides were selected to test against eggs, larvae, and adults of four field strains of B. tabaci Q. Although the field strains differed in their sensitivity to the insecticides, the eggs and larvae of all strains were highly sensitive to cyantraniliprole, and the adults of all strains were highly sensitive to avermectin. The eggs, larvae, and adults of B. tabaci Q were generally more resistant than those of B. tabaci B to the tested insecticides. B. tabaci Q eggs and larvae were sensitive to cyantraniliprole and pyriproxyfen, whereas B. tabaci Q adults were sensitive to avermectin. Field trials should be conducted with cyantraniliprole, pyriproxyfen, and avermectin for control of B. tabaci Q and B in China. PMID:25434040
Gevertz, Diane; Telang, Anita J.; Voordouw, Gerrit; Jenneman, Gary E.
2000-01-01
Bacterial strains CVO and FWKO B were isolated from produced brine at the Coleville oil field in Saskatchewan, Canada. Both strains are obligate chemolithotrophs, with hydrogen, formate, and sulfide serving as the only known energy sources for FWKO B, whereas sulfide and elemental sulfur are the only known electron donors for CVO. Neither strain uses thiosulfate as an energy source. Both strains are microaerophiles (1% O2). In addition, CVO grows by denitrification of nitrate or nitrite whereas FWKO B reduces nitrate only to nitrite. Elemental sulfur is the sole product of sulfide oxidation by FWKO B, while CVO produces either elemental sulfur or sulfate, depending on the initial concentration of sulfide. Both strains are capable of growth under strictly autotrophic conditions, but CVO uses acetate as well as CO2 as its sole carbon source. Neither strain reduces sulfate; however, FWKO B reduces sulfur and displays chemolithoautotrophic growth in the presence of elemental sulfur, hydrogen, and CO2. Both strains grow at temperatures between 5 and 40°C. CVO is capable of growth at NaCl concentrations as high as 7%. The present 16s rRNA analysis suggests that both strains are members of the epsilon subdivision of the division Proteobacteria, with CVO most closely related to Thiomicrospira denitrifcans and FWKO B most closely related to members of the genus Arcobacter. The isolation of these two novel chemolithotrophic sulfur bacteria from oil field brine suggests the presence of a subterranean sulfur cycle driven entirely by hydrogen, carbon dioxide, and nitrate. PMID:10831429
Characterization of Eight Kinds of Marine Magnetotactic Bacteria
NASA Astrophysics Data System (ADS)
Du, H.; Pan, H.; Zhang, W.; Wu, L. F.; Xiao, T.
2017-12-01
Eight marine magnetotactic bacteria were isolated from intertidal sediments. Six of them are magnetococci (RO-1, RO-2, RO-3, RO-4, SC-1 and SC-2), and two of them are manetospirilla (SH-1 and HH-1). Strain RO-1, RO-2, RO-3, and RO-4 were from Lake Yuehu, Rongcheng (the Yellow Sea). Strain SC-1, SC-2 and SH-1 were from Sanya (the South China Sea). Strain HH-1 was from Huiquan Bay, Qingdao (the Yellow Sea). Magnetosomes arranged in a disorganized cluster in RO-1 and RO-4, two chains in SC-2, and in one chain in others. All the magnetosome crystals were prismatic magnetites. Phylogenetic analysis revealed that they all belonged to the Alphaproteobacteria. Strain RO-1, RO-2, RO-3, RO-4, SC-2 and SH-1 are novel cultured magnetotactic bacteria.
Antifouling activities of marine bacteria associated with sponge ( Sigmadocia sp.)
NASA Astrophysics Data System (ADS)
Satheesh, S.; Soniamby, A. R.; Sunjaiy Shankar, C. V.; Mary Josephine Punitha, S.
2012-09-01
The present study aimed at assessing the antifouling activity of bacteria associated with marine sponges. A total of eight bacterial strains were isolated from the surface of sponge Sigmadocia sp., of them, SS02, SS05 and SS06 showed inhibitory activity against biofilm-forming bacteria. The extracts of these 3 strains considerably affected the extracellular polymeric substance producing ability and adhesion of biofilm-forming bacterial strains. In addition to disc diffusion assay, microalgal settlement assay was carried out with the extracts mixed with polyurethane wood polish and coated onto stainless steel coupons. The extract of strain SS05 showed strong microalgal settlement inhibitory activity. Strain SS05 was identified as Bacillus cereus based on its 16S rRNA gene. Metabolites of the bacterial strains associated with marine invertebrates promise to be developed into environment-friendly antifouling agents.
Delamuta, Jakeline Renata Marçon; Ribeiro, Renan Augusto; Menna, Pâmela; Bangel, Eliane Villamil; Hungria, Mariangela
2012-04-01
Symbiotic association of several genera of bacteria collectively called as rhizobia and plants belonging to the family Leguminosae (=Fabaceae) results in the process of biological nitrogen fixation, playing a key role in global N cycling, and also bringing relevant contributions to the agriculture. Bradyrhizobium is considered as the ancestral of all nitrogen-fixing rhizobial species, probably originated in the tropics. The genus encompasses a variety of diverse bacteria, but the diversity captured in the analysis of the 16S rRNA is often low. In this study, we analyzed twelve Bradyrhizobium strains selected from previous studies performed by our group for showing high genetic diversity in relation to the described species. In addition to the 16S rRNA, five housekeeping genes (recA, atpD, glnII, gyrB and rpoB) were analyzed in the MLSA (multilocus sequence analysis) approach. Analysis of each gene and of the concatenated housekeeping genes captured a considerably higher level of genetic diversity, with indication of putative new species. The results highlight the high genetic variability associated with Bradyrhizobium microsymbionts of a variety of legumes. In addition, the MLSA approach has proved to represent a rapid and reliable method to be employed in phylogenetic and taxonomic studies, speeding the identification of the still poorly known diversity of nitrogen-fixing rhizobia in the tropics.
Ricciardi, Annamaria; Blaiotta, Giuseppe; Di Cerbo, Alessandro; Succi, Mariantonietta; Aponte, Maria
2014-06-02
The survival of the autochthonous microflora, of samples collected during Pecorino di Carmasciano cheese manufacturing, was evaluated along the passage through a model mimicking the gastro-intestinal tract. The aim was the selection of lactic acid bacteria potentially able to arrive alive and metabolically active to the colon. The dynamics of lactic microbiota, throughout simulated digestion of cheese samples, were evaluated by means of an approach PCR-DGGE-based. Dominant species after cheese digestion could be related to the Lactobacillus plantarum and Lactobacillus casei groups. Sixty-three strains, which survived to simulated gastro-intestinal transit, were further evaluated for technological features and tolerance to human digestion in several experimental conditions, according to routinely used protocols. Bacterial survival appeared to be, more than strain-specific, strongly affected by experimental conditions, i.e. some strains showed an acceptable survival when resuspended in skim milk but not in ewe milk and vice versa. Nevertheless according to data, one gram of fresh Pecorino di Carmasciano cheese may convey to human colon about the same amount of viable LAB of a probiotic drink. Although it cannot be assumed that lactobacilli introduced with Pecorino have beneficial effects on the host, the healthy impact of autochthonous lactic acid bacteria of naturally fermented food has a broad consensus in the current literature. Copyright © 2014 Elsevier B.V. All rights reserved.
Genomic Encyclopedia of Bacteria and Archaea: Sequencing a Myriad of Type Strains
Kyrpides, Nikos C.; Hugenholtz, Philip; Eisen, Jonathan A.; ...
2014-08-05
Microbes hold the key to life. They hold the secrets to our past (as the descendants of the earliest forms of life) and the prospects for our future (as we mine their genes for solutions to some of the planet's most pressing problems, from global warming to antibiotic resistance). However, the piecemeal approach that has defined efforts to study microbial genetic diversity for over 20 years and in over 30,000 genome projects risks squandering that promise. These efforts have covered less than 20% of the diversity of the cultured archaeal and bacterial species, which represent just 15% of the overallmore » known prokaryotic diversity. Here we call for the funding of a systematic effort to produce a comprehensive genomic catalog of all cultured Bacteria and Archaea by sequencing, where available, the type strain of each species with a validly published name (currently~11,000). This effort will provide an unprecedented level of coverage of our planet's genetic diversity, allow for the large-scale discovery of novel genes and functions, and lead to an improved understanding of microbial evolution and function in the environment.« less
Genomic Encyclopedia of Bacteria and Archaea: Sequencing a Myriad of Type Strains
Kyrpides, Nikos C.; Hugenholtz, Philip; Eisen, Jonathan A.; Woyke, Tanja; Göker, Markus; Parker, Charles T.; Amann, Rudolf; Beck, Brian J.; Chain, Patrick S. G.; Chun, Jongsik; Colwell, Rita R.; Danchin, Antoine; Dawyndt, Peter; Dedeurwaerdere, Tom; DeLong, Edward F.; Detter, John C.; De Vos, Paul; Donohue, Timothy J.; Dong, Xiu-Zhu; Ehrlich, Dusko S.; Fraser, Claire; Gibbs, Richard; Gilbert, Jack; Gilna, Paul; Glöckner, Frank Oliver; Jansson, Janet K.; Keasling, Jay D.; Knight, Rob; Labeda, David; Lapidus, Alla; Lee, Jung-Sook; Li, Wen-Jun; MA, Juncai; Markowitz, Victor; Moore, Edward R. B.; Morrison, Mark; Meyer, Folker; Nelson, Karen E.; Ohkuma, Moriya; Ouzounis, Christos A.; Pace, Norman; Parkhill, Julian; Qin, Nan; Rossello-Mora, Ramon; Sikorski, Johannes; Smith, David; Sogin, Mitch; Stevens, Rick; Stingl, Uli; Suzuki, Ken-ichiro; Taylor, Dorothea; Tiedje, Jim M.; Tindall, Brian; Wagner, Michael; Weinstock, George; Weissenbach, Jean; White, Owen; Wang, Jun; Zhang, Lixin; Zhou, Yu-Guang; Field, Dawn; Whitman, William B.; Garrity, George M.; Klenk, Hans-Peter
2014-01-01
Microbes hold the key to life. They hold the secrets to our past (as the descendants of the earliest forms of life) and the prospects for our future (as we mine their genes for solutions to some of the planet's most pressing problems, from global warming to antibiotic resistance). However, the piecemeal approach that has defined efforts to study microbial genetic diversity for over 20 years and in over 30,000 genome projects risks squandering that promise. These efforts have covered less than 20% of the diversity of the cultured archaeal and bacterial species, which represent just 15% of the overall known prokaryotic diversity. Here we call for the funding of a systematic effort to produce a comprehensive genomic catalog of all cultured Bacteria and Archaea by sequencing, where available, the type strain of each species with a validly published name (currently∼11,000). This effort will provide an unprecedented level of coverage of our planet's genetic diversity, allow for the large-scale discovery of novel genes and functions, and lead to an improved understanding of microbial evolution and function in the environment. PMID:25093819
Bacteria Facilitate Enteric Virus Co-infection of Mammalian Cells and Promote Genetic Recombination.
Erickson, Andrea K; Jesudhasan, Palmy R; Mayer, Melinda J; Narbad, Arjan; Winter, Sebastian E; Pfeiffer, Julie K
2018-01-10
RNA viruses exist in genetically diverse populations due to high levels of mutations, many of which reduce viral fitness. Interestingly, intestinal bacteria can promote infection of several mammalian enteric RNA viruses, but the mechanisms and consequences are unclear. We screened a panel of 41 bacterial strains as a platform to determine how different bacteria impact infection of poliovirus, a model enteric virus. Most bacterial strains, including those extracted from cecal contents of mice, bound poliovirus, with each bacterium binding multiple virions. Certain bacterial strains increased viral co-infection of mammalian cells even at a low virus-to-host cell ratio. Bacteria-mediated viral co-infection correlated with bacterial adherence to cells. Importantly, bacterial strains that induced viral co-infection facilitated genetic recombination between two different viruses, thereby removing deleterious mutations and restoring viral fitness. Thus, bacteria-virus interactions may increase viral fitness through viral recombination at initial sites of infection, potentially limiting abortive infections. Copyright © 2017 Elsevier Inc. All rights reserved.
Zannini, Emanuele; Waters, Deborah M; Coffey, Aidan; Arendt, Elke K
2016-02-01
Exopolysaccharides (EPS)-producing lactic acid bacteria (LAB) are industrially important microorganisms in the development of functional food products and are used as starter cultures or coadjutants to develop fermented foods. There is large variability in EPS production by LAB in terms of chemical composition, quantity, molecular size, charge, presence of side chains, and rigidity of the molecules. The main body of the review will cover practical aspects concerning the structural diversity structure of EPS, and their concrete application in food industries is reported in details. To strengthen the food application and process feasibility of LAB EPS at industrial level, a future academic research should be combined with industrial input to understand the technical shortfalls that EPS can address.
Pellegrino, M; Berardo, N; Giraudo, J; Nader-Macías, M E F; Bogni, C
2017-08-24
The use of lactic acid bacteria (LAB) in animal feed, constitute an alternative tool for bovine mastitis prevention. Previously, two LAB strains were isolated from bovine milk and selected for their probiotics properties. So far, immune response of inoculating LAB in bovine udders at dry-off period has not been investigated. The immunoglobulin isotype levels and memory cell proliferation in blood and milk of animals inoculated with Lactobacillus lactis subsp. lactis CRL1655 and Lactobacillus perolens CRL1724 at dry-off period was studied. Ten animals were inoculated intramammarily with 10 6 cells of each LAB (IG) and 2 animals used as control (NIG). Milk and blood samples were taken before inoculation and 1, 2, 4, 6, 12 and 24 h and 7 and 14 days after inoculation. Somatic cell count (SCC) in milk, the presence of bovine mastitis pathogens, the levels of antibodies and lymphocyte proliferation were determined. In the IG, the SCC was <250,000 cells/ml up to 4 h after intramammary inoculation. Six and 12 h after inoculation, the SCC increased up to 600,000 and 2,000,000 cells/ml, respectively. In the NIG, the SCC reached the maximum value 7 days after inoculation. Microbiological analysis showed that all samples were negative for major bovine mastitis pathogens after 24-48 h of incubation. In general, LAB inoculation increased the amount of IgG isotypes in blood and milk, and these antibodies were able to recognise Staphylococcus aureus epitopes. Lymphocytes proliferation was significantly higher in the IG at all time points assayed, following LAB or S. aureus stimulation. The lymphocytes of animals inoculated with LAB do not react in vitro to the presence of S. aureus antigen.. The results showed that probiotic microorganisms could be a natural and effective alternative in the prevention of bovine mastitis at dry-off period and act as immunomodulatory stimulating local and systemic defence lines.
NASA Astrophysics Data System (ADS)
Ayuningrum, D.; Kristiana, R.; Asagabaldan, M. A.; Sabdono, A.; Radjasa, O. K.; Nuryadi, H.; Trianto, A.
2017-02-01
Pavona sp. is highly spread over Indonesian waters including Panjang Island. Several studies showed that bacteria symbionts hardcoral were the big source of antibiotic product, but there was limited research of the bacteria symbionts with hardcoral Pavona sp. In this research bacteria symbionts from hardcoral Pavona sp. had been collected from Panjang Island, Jepara. Marine bacteria symbionts were isolated by serial dillution method, while antibacterial activity was performed by using overlay and agar block method. The total of 2 from 5 isolates were active to MDR bacteria such as Enterobacter aerogenes and Acinetobacter baumanii, the code were PHC 44/04 and PHC 44/05. Then both of them were identified by morphological and molecular DNA characterization using 16 S rRNA gene sequence. The result of 16 S rRNA identification shows PHC 44/04 has 99% similarities with Virgibacillus salarius strain sa-Vb 1, while PHC 44/05 shows 99% similarities with Pseudoalteromonas flavipulchra strain NCIMB 2033.
Lactic acid bacteria with potential to eliminate fungal spoilage in foods.
Rouse, S; Harnett, D; Vaughan, A; van Sinderen, D
2008-03-01
To investigate antifungal activity produced by lactic acid bacteria (LAB) isolated from malted cereals and to determine if such LAB have the capacity to prevent fungal growth in a particular food model system. The effect of pH, temperature and carbon source on production of antifungal activity by four LAB was determined. Pediococcus pentosaceus was used to conduct a trial to determine if it is feasible to eliminate Penicillium expansum, the mould responsible for apple rot, using an apple model. Penicillium expansum was incapable of growth during the trial on apple-based agar plates inoculated with the antifungal-producing culture, whereas the mould did grow on apple plates inoculated with an LAB possessing no antifungal activity. Partial characterization of the antifungal compounds indicates that their activity is likely to be because of production of antifungal peptides. The trial conducted showed that the antifungal culture has the ability to prevent growth of the mould involved in apple spoilage, using apples as a model. The ability of an LAB to prevent growth of Pen. expansum using the apple model suggests that these antifungal LAB have potential applications in the food industry to prevent fungal spoilage of food.
Berkeley Lab Berkeley Lab A-Z Index Phone Book Jobs Search DOE Help Berkeley Lab Training Welcome Welcome to Berkeley Lab Training! Login to access your LBNL Training Profile. This provides quick access to all of the courses you need. Look below, to learn about different types of training available at
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.
NASA Astrophysics Data System (ADS)
Cho, Gyu Sung; Do, Hyung Ki
2006-06-01
Seventeen lactic acid bacterial strains (LAB) were isolated using MRS agar medium from Jeotgal, a Korean fermented food, purchased at the Jukdo market of Pohang. To identify the strains isolated, they were tested by examining their cell morphologies, gram-staining, catalase activity, arginine hydrolase activity, D-L lactate form and carbohydrate fermentation. According to the phenotypic characteristics, three strains were tent atively identified as Lactobacillus spp., ten were Enterococcus spp. (or Streptococcus spp., or Pediococcus spp.) and the rest were Leuconostoc spp. (or Weissella spp.). Five strains among 17 were chosen by preliminary bacteriocin activity test. Four bacterial strains which inhibited both indicator microorganisms were identified by 16S rRNA sequencing. The results are as follows; Leuconostoc mesenteroides (HK 4), Leuconostoc mesenteroides (HK 5), Leuconostoc mesenteroides(HK 11), Streptococcus salivarius(HK 8). In order to check LAB which are showing a high survival rate in gut, we investigated three strains inhibiting both indicator microorganisms in artificial gastric acid and bile juice -all except HK8. The three strains mentioned above grew in extreme low acid conditions.
In vitro testing of commercial and potential probiotic lactic acid bacteria.
Jensen, Hanne; Grimmer, Stine; Naterstad, Kristine; Axelsson, Lars
2012-02-01
Probiotics are defined as live microorganisms which when administered in adequate amounts confer a health benefit on the host. The objective of this study was to investigate the diversity of selected commercial and potential probiotic lactic acid bacteria using common in vitro screening assays such as transit tolerance in the upper human gastrointestinal tract, adhesion capacity to human intestinal cell lines and effect on epithelial barrier function. The selected bacteria include strains of Lactobacillus plantarum, Lactobacillus pentosus, Lactobacillus farciminis, Lactobacillus sakei, Lactobacillus gasseri, Lactobacillus rhamnosus, Lactobacillus reuteri and Pediococcus pentosaceus. Viable counts after simulated gastric transit tolerance showed that L. reuteri strains and P. pentosaceus tolerate gastric juice well, with no reduction of viability, whereas L. pentosus, L. farciminis and L. sakei strains lost viability over 180min. All strains tested tolerate the simulated small intestinal juice well. The bacterial adhesion capacity to human intestinal cells revealed major species and strain differences. Overall, L. plantarum MF1298 and three L. reuteri strains had a significant higher adhesion capacity compared to the other strains tested. All strains, both living and UV-inactivated, had little effect on the epithelial barrier function. However, living L. reuteri strains revealed a tendency to increase the transepithelial electrical resistance (TER) from 6 to 24h. This work demonstrates the diversity of 18 potential probiotic bacteria, with major species and strain specific effects in the in vitro screening assays applied. Overall, L. reuteri strains reveal some interesting characteristics compared to the other strains investigated. Copyright © 2011 Elsevier B.V. All rights reserved.
Survival differences among freeze-dried genetically engineered and wild-type bacteria.
Israeli, E; Shaffer, B T; Hoyt, J A; Lighthart, B; Ganio, L M
1993-01-01
Because the death mechanisms of freeze-dried and air-dried bacteria are thought to be similar, freeze-drying was used to investigate the survival differences between potentially airborne genetically engineered microorganisms and their wild types. To this end, engineered strains of Escherichia coli and Pseudomonas syringae were freeze-dried and exposed to air, visible light, or both. The death rates of all engineered strains were significantly higher than those of their parental strains. Light and air exposure were found to increase the death rates of all strains. Application of death rate models to freeze-dried engineered bacteria to be released into the environment is discussed. PMID:8434925
Tomazetto, Geizecler; Hahnke, Sarah; Maus, Irena; Wibberg, Daniel; Pühler, Alfred; Schlüter, Andreas; Klocke, Michael
2014-12-20
The bacterium Peptoniphilus sp. strain ING2-D1G (DSM 28672), a mesophilic and obligate anaerobic bacterium belonging to the order Clostridiales was isolated from a biogas-producing lab-scale completely stirred tank reactor (CSTR) optimized for anaerobic digestion of maize silage in co-fermentation with pig and cattle manure. In this study, the whole genome sequence of Peptoniphilus sp. strain ING2-D1G, a new isolate potentially involved in protein breakdown and acidogenesis during biomass degradation, is reported. The chromosome of this strain is 1.6Mb in size and encodes genes predicted to be involved in the production of acetate, lactate and butyrate specifying the acidogenic metabolism of the isolate. Copyright © 2014 Elsevier B.V. All rights reserved.
2013-01-01
Background The microorganisms intended for use as probiotics in aquaculture should exert antimicrobial activity and be regarded as safe not only for the aquatic hosts but also for their surrounding environments and humans. The objective of this work was to investigate the antimicrobial/bacteriocin activity against fish pathogens, the antibiotic susceptibility, and the prevalence of virulence factors and detrimental enzymatic activities in 99 Lactic Acid Bacteria (LAB) (59 enterococci and 40 non-enterococci) isolated from aquatic animals regarded as human food. Results These LAB displayed a broad antimicrobial/bacteriocin activity against the main Gram-positive and Gram-negative fish pathogens. However, particular safety concerns based on antibiotic resistance and virulence factors were identified in the genus Enterococcus (86%) (Enterococcus faecalis, 100%; E. faecium, 79%). Antibiotic resistance was also found in the genera Weissella (60%), Pediococcus (44%), Lactobacillus (33%), but not in leuconostocs and lactococci. Antibiotic resistance genes were found in 7.5% of the non-enterococci, including the genera Pediococcus (12.5%) and Weissella (6.7%). One strain of both Pediococcus pentosaceus and Weissella cibaria carried the erythromycin resistance gene mef(A/E), and another two P. pentosaceus strains harboured lnu(A) conferring resistance to lincosamides. Gelatinase activity was found in E. faecalis and E. faecium (71 and 11%, respectively), while a low number of E. faecalis (5%) and none E. faecium exerted hemolytic activity. None enterococci and non-enterococci showed bile deconjugation and mucin degradation abilities, or other detrimental enzymatic activities. Conclusions To our knowledge, this is the first description of mef(A/E) in the genera Pediococcus and Weissella, and lnu(A) in the genus Pediococcus. The in vitro subtractive screening presented in this work constitutes a valuable strategy for the large-scale preliminary selection of putatively safe LAB
In vitro suppression of fungi caused by combinations of apparently non-antagonistic soil bacteria.
de Boer, Wietse; Wagenaar, Anne-Marieke; Klein Gunnewiek, Paulien J A; van Veen, Johannes A
2007-01-01
We hypothesized that apparently non-antagonistic soil bacteria may contribute to suppression of fungi during competitive interactions with other bacteria. Four soil bacteria (Brevundimonas sp., Luteibacter sp., Pedobacter sp. and Pseudomonas sp.) that exhibited little or no visible antifungal activity on different agar media were prescribed. Single and mixed strains of these species were tested for antagonism on a nutrient-poor agar medium against the plant pathogenic fungi Fusarium culmorum and Rhizoctonia solani and the saprotrophic fungus Trichoderma harzianum. Single bacterial strains caused little to moderate growth reduction of fungi (quantified as ergosterol), most probably due to nutrient withdrawal from the media. Growth reduction of fungi by the bacterial mixture was much stronger than that by the single strains. This appeared to be mostly due to competitive interactions between the Pseudomonas and Pedobacter strains. We argue that cohabitation of these strains triggered antibiotic production via interspecific interactions and that the growth reduction of fungi was a side-effect caused by the sensitivity of the fungi to bacterial secondary metabolites. Induction of gliding behavior in the Pedobacter strain by other strains was also observed. Our results indicate that apparently non-antagonistic soil bacteria may be important contributors to soil suppressiveness and fungistasis when in a community context.
Xie, Wen; Liu, Yang; Wang, Shaoli; Wu, Qingjun; Pan, Huipeng; Yang, Xin; Guo, Litao; Zhang, Youjun
2014-01-01
Whitefly biotypes B and Q are the two most damaging members of the Bemisia tabaci (Hemiptera: Aleyrodidae) species complex. Control of B. tabaci (and especially of Q) has been impaired by resistance to commonly used insecticides. To find new insecticides for B. tabaci management in China, we investigated the sensitivity of eggs, larvae, and adults of laboratory strains of B and Q (named Lab-B and Lab-Q) and field strains of Q to several insecticides. For eggs, larvae, and adults of B. tabaci and for six insecticides (cyantraniliprole, chlorantraniliprole, pyriproxyfen, buprofezin, acetamiprid, and thiamethoxam), LC50 values were higher for Lab-Q than for Lab-B; avermectin LC50 values, however, were low for adults of both Lab-Q and Lab-B. Based on the laboratory results, insecticides were selected to test against eggs, larvae, and adults of four field strains of B. tabaci Q. Although the field strains differed in their sensitivity to the insecticides, the eggs and larvae of all strains were highly sensitive to cyantraniliprole, and the adults of all strains were highly sensitive to avermectin. The eggs, larvae, and adults of B. tabaci Q were generally more resistant than those of B. tabaci B to the tested insecticides. B. tabaci Q eggs and larvae were sensitive to cyantraniliprole and pyriproxyfen, whereas B. tabaci Q adults were sensitive to avermectin. Field trials should be conducted with cyantraniliprole, pyriproxyfen, and avermectin for control of B. tabaci Q and B in China. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.
Probiotic bacteria affect the composition of salivary pellicle and streptococcal adhesion in vitro.
Haukioja, A; Loimaranta, V; Tenovuo, J
2008-08-01
The use of probiotic bacteria is increasing worldwide and at least some of them can transiently colonize the oral cavity. Several studies have shown that probiotic bacteria, which are often thought of in relation only to intestinal health, can also affect the oral ecology, but the mechanisms for this are largely unknown. The aim of this study was to investigate in vitro if the probiotic bacteria used in commercial products affect the protein composition of the salivary pellicle and the adherence of other oral bacteria. Salivary pellicle on hydroxyapatite and the adhesion of two oral streptococci, Streptococcus mutans and Streptococcus gordonii, were used as a model. Probiotic bacteria that bound to saliva-coated hydroxyapatite reduced the adhesion of S. mutans but the inhibitory effect on the adherence of S. gordonii was weaker. Salivary pellicle protein composition was modified by all the strains tested. The modifications in the pellicle affected the adherence of S. mutans but not of S. gordonii. Two of the proteins missing from the pellicles made of saliva-treated with the probiotic bacteria were identified as salivary agglutinin gp340 and salivary peroxidase. All bacterial strains bound salivary agglutinin gp340. The ability of the probiotic bacteria to degrade peroxidase was demonstrated with purified bovine lactoperoxidase and two of the probiotic strains. This in vitro study showed that probiotic strains used in commercial products may affect the oral ecology by specifically preventing the adherence of other bacteria and by modifying the protein composition of the salivary pellicle.
Dunlap, Paul V.; Ast, Jennifer C.
2005-01-01
Bacteria forming light-organ symbiosis with deep-sea chlorophthalmid fishes (Aulopiformes: Chlorophthalmidae) are considered to belong to the species Photobacterium phosphoreum. The identification of these bacteria as P. phosphoreum, however, was based exclusively on phenotypic traits, which may not discriminate between phenetically similar but evolutionarily distinct luminous bacteria. Therefore, to test the species identification of chlorophthalmid symbionts, we carried out a genomotypic (repetitive element palindromic PCR genomic profiling) and phylogenetic analysis on strains isolated from the perirectal light organ of Chlorophthalmus albatrossis. Sequence analysis of the 16S rRNA gene of 10 strains from 5 fish specimens placed these bacteria in a cluster related to but phylogenetically distinct from the type strain of P. phosphoreum, ATCC 11040T, and the type strain of Photobacterium iliopiscarium, ATCC 51760T. Analysis of gyrB resolved the C. albatrossis strains as a strongly supported clade distinct from P. phosphoreum and P. iliopiscarium. Genomic profiling of 109 strains from the 5 C. albatrossis specimens revealed a high level of similarity among strains but allowed identification of genomotypically different types from each fish. Representatives of each type were then analyzed phylogenetically, using sequence of the luxABFE genes. As with gyrB, analysis of luxABFE resolved the C. albatrossis strains as a robustly supported clade distinct from P. phosphoreum. Furthermore, other strains of luminous bacteria reported as P. phosphoreum, i.e., NCIMB 844, from the skin of Merluccius capensis (Merlucciidae), NZ-11D, from the light organ of Nezumia aequalis (Macrouridae), and pjapo.1.1, from the light organ of Physiculus japonicus (Moridae), grouped phylogenetically by gyrB and luxABFE with the C. albatrossis strains, not with ATCC 11040T. These results demonstrate that luminous bacteria symbiotic with C. albatrossis, together with certain other strains of
Dunlap, Paul V; Ast, Jennifer C
2005-02-01
Bacteria forming light-organ symbiosis with deep-sea chlorophthalmid fishes (Aulopiformes: Chlorophthalmidae) are considered to belong to the species Photobacterium phosphoreum. The identification of these bacteria as P. phosphoreum, however, was based exclusively on phenotypic traits, which may not discriminate between phenetically similar but evolutionarily distinct luminous bacteria. Therefore, to test the species identification of chlorophthalmid symbionts, we carried out a genomotypic (repetitive element palindromic PCR genomic profiling) and phylogenetic analysis on strains isolated from the perirectal light organ of Chlorophthalmus albatrossis. Sequence analysis of the 16S rRNA gene of 10 strains from 5 fish specimens placed these bacteria in a cluster related to but phylogenetically distinct from the type strain of P. phosphoreum, ATCC 11040(T), and the type strain of Photobacterium iliopiscarium, ATCC 51760(T). Analysis of gyrB resolved the C. albatrossis strains as a strongly supported clade distinct from P. phosphoreum and P. iliopiscarium. Genomic profiling of 109 strains from the 5 C. albatrossis specimens revealed a high level of similarity among strains but allowed identification of genomotypically different types from each fish. Representatives of each type were then analyzed phylogenetically, using sequence of the luxABFE genes. As with gyrB, analysis of luxABFE resolved the C. albatrossis strains as a robustly supported clade distinct from P. phosphoreum. Furthermore, other strains of luminous bacteria reported as P. phosphoreum, i.e., NCIMB 844, from the skin of Merluccius capensis (Merlucciidae), NZ-11D, from the light organ of Nezumia aequalis (Macrouridae), and pjapo.1.1, from the light organ of Physiculus japonicus (Moridae), grouped phylogenetically by gyrB and luxABFE with the C. albatrossis strains, not with ATCC 11040(T). These results demonstrate that luminous bacteria symbiotic with C. albatrossis, together with certain other strains of
Sudenko, V I; Groma, L I; Podgorskiĭ, V S
1996-01-01
Study of antagonistic properties of microaerophilic bacteria isolated from human and mink gastroenteric tract have helped to establish differences in species composition, quantity and level of antagonistic activity of the studied microorganisms in respect to pathogenic microflora. It is shown that lactic acid bacteria identified as Lactobacillus fermentum and L. reuteri prevail among the strains isolated from the stomach and thin intestine of minks kept in the 30-km zone of Chernobyl NPP. Species composition of microaerophilic bacteria isolated from the digestive tract of the control minks is more variable. Antagonistically active bifidobacteria prevail in large intestine of experimental and control animals. Strains of lactic acid bacteria with the expressed antagonistic activity belonging to L. bavaricus, L. reuteri, L. coryniformis and L. maltaromicus have been found parallel with such known producers of antibiotic-like substances as L. fermentum. L. acidophilum. Streptococcus faecalis and bifidobacteria. L. maltaromicus most frequently occurred among antagonistically active strains revealed in feces of people which stayed in the zone of liquidation of the Chernobyl accident. Microaerophilic strains of bacteria (lactic acid, bifidobacteria and enterococci) manifest the expressed antagonistic activity connected with the capacity to not only acid formation but also to accumulation of antibiotic products of unknown nature. A strain of lactic acid bacteria L. fermentum 91 has been isolated from the contents of human gastroenteric tract. These bacteria are distinguished by most expressed and stable antagonism and characterized by the lack of pathogenicity in respect of albino mice that may be used to raise the microorganism resistance to gastric diseases.
Abdelmaksoud, Abdallah A.; Koparde, Vishal N.; Sheth, Nihar U.; Serrano, Myrna G.; Glascock, Abigail L.; Fettweis, Jennifer M.; Strauss, Jerome F.; Buck, Gregory A.
2016-01-01
Vaginal lactobacilli can inhibit colonization by and growth of other bacteria, thereby preventing development of bacterial vaginosis (BV). Amongst the lactobacilli, Lactobacillus crispatus appears to be particularly effective at inhibiting growth of BV-associated bacteria. Nonetheless, some women who are colonized with this species can still develop clinical BV. Therefore, we sought to determine whether strains of L. crispatus that colonize women with lactobacilli-dominated vaginal microbiomes are distinct from strains that colonize women who develop BV. The genomes of L. crispatus isolates from four women with lactobacilli-dominated vaginal microbiomes ( < 1 % 16S rRNA reads above threshold from genera other than Lactobacillus) and four women with microbiomes containing BV-associated bacteria (>12 % 16S rRNA reads from bacterial taxa associated with BV) were sequenced and compared. Lactic acid production by the different strains was quantified. Phage induction in the strains was also analysed. There was considerable genetic diversity between strains, and several genes were exclusive to either the strains from Lactobacillus-dominated microbiomes or those containing BV-associated bacteria. Overall, strains from microbiomes dominated by lactobacilli did not differ from strains from microbiomes containing BV-associated bacteria with respect to lactic acid production. All of the strains contained multiple phage, but there was no clear distinction between the presence or absence of BV-associated bacteria with respect to phage-induced lysis. Genes found to be exclusive to the Lactobacillus-dominated versus BV-associated bacteria-containing microbiomes could play a role in the maintenance of vaginal health and the development of BV, respectively. PMID:26747455
Abdelmaksoud, Abdallah A; Koparde, Vishal N; Sheth, Nihar U; Serrano, Myrna G; Glascock, Abigail L; Fettweis, Jennifer M; Strauss, Jerome F; Buck, Gregory A; Jefferson, Kimberly K
2016-03-01
Vaginal lactobacilli can inhibit colonization by and growth of other bacteria, thereby preventing development of bacterial vaginosis (BV). Amongst the lactobacilli, Lactobacillus crispatus appears to be particularly effective at inhibiting growth of BV-associated bacteria. Nonetheless, some women who are colonized with this species can still develop clinical BV. Therefore, we sought to determine whether strains of L. crispatus that colonize women with lactobacilli-dominated vaginal microbiomes are distinct from strains that colonize women who develop BV. The genomes of L. crispatus isolates from four women with lactobacilli-dominated vaginal microbiomes ( <1% 16S rRNA reads above threshold from genera other than Lactobacillus) and four women with microbiomes containing BV-associated bacteria (>12% 16S rRNA reads from bacterial taxa associated with BV) were sequenced and compared. Lactic acid production by the different strains was quantified. Phage induction in the strains was also analysed. There was considerable genetic diversity between strains, and several genes were exclusive to either the strains from Lactobacillus-dominated microbiomes or those containing BV-associated bacteria. Overall, strains from microbiomes dominated by lactobacilli did not differ from strains from microbiomes containing BV-associated bacteria with respect to lactic acid production. All of the strains contained multiple phage, but there was no clear distinction between the presence or absence of BV-associated bacteria with respect to phage-induced lysis. Genes found to be exclusive to the Lactobacillus-dominated versus BV-associated bacteria-containing microbiomes could play a role in the maintenance of vaginal health and the development of BV, respectively.
Liu, Chengcheng; Hu, Min; Ma, Dandan; Lei, Jin'e; Xu, Jiru
2016-02-01
The worldwide increase in bacterial antibiotic resistance has led to a search for alternative antibacterial therapies. A promising approach to killing antibiotic-resistant bacteria is photodynamic antimicrobial chemotherapy, which uses light in combination with a photosensitizer to induce a phototoxic reaction. We evaluated the photodynamic inactivation (PDI) efficiency of hematoporphyrin monomethyl ether (HMME) on antibiotic-resistant bacteria and biofilms. HMME exhibited no significant dark toxicity and provided dose-dependent inactivation of antibiotic-resistant bacteria and biofilms. After incubation with 100-μM HMME and irradiation with 72-J cm(-2) white light, 4.19-7.59 log10 reductions in survival were achieved in planktonic suspension. Antibiotic-resistant strains were as susceptible to PDI in biofilms as in planktonic suspensions, but the inactivation of bacterial cells in biofilms was attenuated. In addition, gram-positive bacterial strains and biofilms were more susceptible than gram-negative strains and biofilms to the PDI effect of HMME. Thus, HMME is a promising photosensitizer for the treatment of infectious diseases caused by antibiotic-resistant bacteria, especially gram-positive bacteria.
Gisi, Daniel; Willi, Laurent; Traber, Hubert; Leisinger, Thomas; Vuilleumier, Stéphane
1998-01-01
Methylobacterium sp. strain DM4 and Methylophilus sp. strain DM11 can grow with dichloromethane (DCM) as the sole source of carbon and energy by virtue of homologous glutathione-dependent DCM dehalogenases with markedly different kinetic properties (the kcat values of the enzymes of these strains are 0.6 and 3.3 s−1, respectively, and the Km values are 9 and 59 μM, respectively). These strains, as well as transconjugant bacteria expressing the DCM dehalogenase gene (dcmA) from DM11 or DM4 on a broad-host-range plasmid in the background of dcmA mutant DM4-2cr, were investigated by growing them under growth-limiting conditions and in the presence of an excess of DCM. The maximal growth rates and maximal levels of dehalogenase for chemostat-adapted bacteria were higher than the maximal growth rates and maximal levels of dehalogenase for batch-grown bacteria. The substrate saturation constant of strain DM4 was much lower than the Km of its associated dehalogenase, suggesting that this strain is adapted to scavenge low concentrations of DCM. Strains and transconjugants expressing the DCM dehalogenase from strain DM11, on the other hand, had higher growth rates than bacteria expressing the homologous dehalogenase from strain DM4. Competition experiments performed with pairs of DCM-degrading strains revealed that a strain expressing the dehalogenase from DM4 had a selective advantage in continuous culture under substrate-limiting conditions, while strains expressing the DM11 dehalogenase were superior in batch culture when there was an excess of substrate. Only DCM-degrading bacteria with a dcmA gene similar to that from strain DM4, however, were obtained in batch enrichment cultures prepared with activated sludge from sewage treatment plants. PMID:9546153
NASA Astrophysics Data System (ADS)
Lestari, R. P.; Nissa, C.; Afifah, D. N.; Anjani, G.; Rustanti, N.
2018-02-01
Alternative treatment for metabolic syndrome can be done by providing a diet consist of functional foods or beverages. Synbiotic yoghurt containing binahong leaf extract which high in antioxidant, total LAB and fiber can be selected to reduce the risk of metabolic syndrome. The effect of binahong leaf extract in synbiotic yoghurt against total LAB, antioxidant activity, and acceptance were analyzed. The experiment was done with complete randomized design with addition of binahong leaf extract 0% (control); 0.12%; 0.25%; 0.5% in synbiotic yoghurt. Analysis of total LAB using Total Plate Count test, antioxidant activity using DPPH, and acceptance were analyzed by hedonic test. The addition of binahong leaf extract in various doses in synbiotic yoghurt decreased total LAB without significant effect (p=0,145). There was no effect of addition binahong leaf extract on antioxidant activity (p=0,297). The addition of binahong leaf extract had an effect on color, but not on aroma, texture and taste. The best result was yoghurt synbiotic with addition of 0,12% binahong leaf extract. Conclusion of the research was the addition of binahong leaf extract to synbiotic yogurt did not significantly affect total LAB, antioxidant activity, aroma, texture and taste; but had a significant effect on color.
Watanabe, Masanori; Techapun, Charin; Kuntiya, Ampin; Leksawasdi, Noppol; Seesuriyachan, Phisit; Chaiyaso, Thanongsak; Takenaka, Shinji; Maeda, Isamu; Koyama, Masahiro; Nakamura, Kozo
2017-02-01
A lactic acid producing bacterium, Lactobacillus rhamnosus M-23, newly isolated from a rice washing drainage storage tank was found to produce l-(+)-lactic acid from a non-sterilized mixture of rice washing drainage and rice bran without any additions of nutrients under the simultaneous saccharification and fermentation (SSF) process. This strain has the ability to utilize the non-sterilized rice washing drainage and rice bran as a source of carbohydrate, saccharifying enzymes and nutrients for lactic acid production. Observation of extracellular protease activity in SSF culture broth showed that a higher protease activity was present in strain M-23 than in other isolated lactic acid producing bacteria (LABs). To investigate the structural changes of solid particles of rice washing drainage throughout LAB cultivation, scanning electron microscopic (SEM) observation and Fourier transform infrared-spectroscopy (FT-IR) analysis were performed. The results of the SEM observation showed that the surface material could be removed from solid particles of rice washing drainage treated by culture broth (supernatant) of strain M-23, thus exposing the crystal structure of the starch particle surface. The results of the FT-IR analysis revealed that the specific transmittance decrease of the CC and CO stretching and OH group of the solid particles of the rice washing drainage were highly correlated with the produced lactic acid concentration and extracellular protease activity, respectively. These results demonstrate the high lactic acid producing ability of strain M-23 from a non-sterilized mixture of rice washing drainage and rice bran under the SSF condition due to the removal of proteinaceous material and exposure of the starch particle surface by extracellular protease. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.
Method for construction of bacterial strains with increased succinic acid production
Donnelly, Mark I.; Sanville-Millard, Cynthia; Chatterjee, Ranjini
2000-01-01
A fermentation process for producing succinic acid is provided comprising selecting a bacterial strain that does not produce succinic acid in high yield, disrupting the normal regulation of sugar metabolism of said bacterial strain, and combining the mutant bacterial strain and selected sugar in anaerobic conditions to facilitate production of succinic acid. Also provided is a method for changing low yield succinic acid producing bacteria to high yield succinic acid producing bacteria comprising selecting a bacterial strain having a phosphotransferase system and altering the phosphotransferase system so as to allow the bacterial strain to simultaneously metabolize different sugars.
Bai, Hongjuan; Cochet, Nelly; Pauss, André; Lamy, Edvina
2017-02-01
Experimental and modeling studies were performed to investigate bacteria deposition behavior in unsaturated porous media. The coupled effect of different forces, acting on bacteria at solid-air-water interfaces and their relative importance on bacteria deposition mechanisms was explored by calculating Derjaguin-Landau-Verwey-Overbeek (DLVO) and non-DLVO interactions such as hydrophobic, capillary and hydrodynamic forces. Negatively charged non-motile bacteria and quartz sands were used in packed column experiments. The breakthrough curves and retention profiles of bacteria were simulated using the modified Mobile-IMmobile (MIM) model, to identify physico-chemical attachment or physical straining mechanisms involved in bacteria retention. These results indicated that both mechanisms might occur in both sand. However, the attachment was found to be a reversible process, because attachment coefficients were similar to those of detachment. DLVO calculations supported these results: the primary minimum did not exist, suggesting no permanent retention of bacteria to solid-water and air-water interfaces. Calculated hydrodynamic and resisting torques predicted that bacteria detachment in the secondary minimum might occur. The capillary potential energy was greater than DLVO, hydrophobic and hydrodynamic potential energies, suggesting that film straining by capillary forces might largely govern bacteria deposition under unsaturated conditions. Copyright © 2016 Elsevier B.V. All rights reserved.
Romaidi; Ueki, Tatsuya
2016-06-01
Isolation of naturally occurring bacterial strains from metal-rich environments has gained popularity due to the growing need for bioremediation technologies. In this study, we found that the vanadium concentration in the intestine of the vanadium-rich ascidian Ascidia sydneiensis samea could reach 0.67 mM, and thus, we isolated vanadium-resistant bacteria from the intestinal contents and determined the ability of each bacterial strain to accumulate vanadium and other heavy metals. Nine strains of vanadium-resistant bacteria were successfully isolated, of which two strains, V-RA-4 and S-RA-6, accumulated vanadium at a higher rate than did the other strains. The maximum vanadium absorption by these bacteria was achieved at pH 3, and intracellular accumulation was the predominant mechanism. Each strain strongly accumulated copper and cobalt ions, but accumulation of nickel and molybdate ions was relatively low. These bacterial strains can be applied to protocols for bioremediation of vanadium and heavy metal toxicity.
Beer spoilage bacteria and hop resistance.
Sakamoto, Kanta; Konings, Wil N
2003-12-31
For brewing industry, beer spoilage bacteria have been problematic for centuries. They include some lactic acid bacteria such as Lactobacillus brevis, Lactobacillus lindneri and Pediococcus damnosus, and some Gram-negative bacteria such as Pectinatus cerevisiiphilus, Pectinatus frisingensis and Megasphaera cerevisiae. They can spoil beer by turbidity, acidity and the production of unfavorable smell such as diacetyl or hydrogen sulfide. For the microbiological control, many advanced biotechnological techniques such as immunoassay and polymerase chain reaction (PCR) have been applied in place of the conventional and time-consuming method of incubation on culture media. Subsequently, a method is needed to determine whether the detected bacterium is capable of growing in beer or not. In lactic acid bacteria, hop resistance is crucial for their ability to grow in beer. Hop compounds, mainly iso-alpha-acids in beer, have antibacterial activity against Gram-positive bacteria. They act as ionophores which dissipate the pH gradient across the cytoplasmic membrane and reduce the proton motive force (pmf). Consequently, the pmf-dependent nutrient uptake is hampered, resulting in cell death. The hop-resistance mechanisms in lactic acid bacteria have been investigated. HorA was found to excrete hop compounds in an ATP-dependent manner from the cell membrane to outer medium. Additionally, increased proton pumping by the membrane bound H(+)-ATPase contributes to hop resistance. To energize such ATP-dependent transporters hop-resistant cells contain larger ATP pools than hop-sensitive cells. Furthermore, a pmf-dependent hop transporter was recently presented. Understanding the hop-resistance mechanisms has enabled the development of rapid methods to discriminate beer spoilage strains from nonspoilers. The horA-PCR method has been applied for bacterial control in breweries. Also, a discrimination method was developed based on ATP pool measurement in lactobacillus cells. However
Pereira, Tomás Pellizzaro; do Amaral, Fernanda Plucani; Dall'Asta, Pamela; Brod, Fábio Cristiano Angonesi; Arisi, Ana Carolina Maisonnave
2014-07-01
The plant growth promoting bacteria Herbaspirillum seropedicae SmR1 is an endophytic diazotroph found in several economically important crops. Considering that methods to monitor the plant-bacteria interaction are required, our objective was to develop a real-time PCR method for quantification of PGPB H. seropedicae in the rhizosphere of maize seedlings. Primer pairs were designed, and their specificity was verified using DNA from 12 different bacterial species. Ten standard curves of qPCR assay using HERBAS1 primers and tenfold serial dilutions of H. seropedicae SmR1 DNA were performed, and PCR efficiency of 91 % and correlation coefficient of 0.99 were obtained. H. seropedicae SmR1 limit of detection was 10(1) copies (corresponding to 60.3 fg of bacterial DNA). qPCR assay using HERBAS1 was used to detect and quantify H. seropedicae strain SmR1 in inoculated maize roots, cultivated in vitro and in pots, harvested 1, 4, 7, and 10 days after inoculation. The estimated bacterial DNA copy number per gram of root was in the range 10(7)-10(9) for plants grown in vitro and it was around 10(6) for plants grown in pots. Primer pair HERBAS1 was able to quantify H. seropedicae SmR1, and this assay can be useful for monitoring plant-bacteria interaction.
Papalexandratou, Zoi; Vrancken, Gino; De Bruyne, Katrien; Vandamme, Peter; De Vuyst, Luc
2011-10-01
Spontaneous organic cocoa bean box fermentations were carried out on two different farms in Brazil. Physical parameters, microbial growth, bacterial species diversity [mainly lactic acid bacteria (LAB) and acetic acid bacteria (AAB)], and metabolite kinetics were monitored, and chocolates were produced from the fermented dry cocoa beans. The main end-products of the catabolism of the pulp substrates (glucose, fructose, and citric acid) by yeasts, LAB, and AAB were ethanol, lactic acid, mannitol, and/or acetic acid. Lactobacillus fermentum and Acetobacter pasteurianus were the predominating bacterial species of the fermentations as revealed through (GTG)(5)-PCR fingerprinting of isolates and PCR-DGGE of 16S rRNA gene PCR amplicons of DNA directly extracted from fermentation samples. Fructobacillus pseudoficulneus, Lactobacillus plantarum, and Acetobacter senegalensis were among the prevailing species during the initial phase of the fermentations. Also, three novel LAB species were found. This study emphasized the possible participation of Enterobacteriaceae in the cocoa bean fermentation process. Tatumella ptyseos and Tatumella citrea were the prevailing enterobacterial species in the beginning of the fermentations as revealed by 16S rRNA gene-PCR-DGGE. Finally, it turned out that control over a restricted bacterial species diversity during fermentation through an ideal post-harvest handling of the cocoa beans will allow the production of high-quality cocoa and chocolates produced thereof, independent of the fermentation method or farm. Copyright © 2011 Elsevier Ltd. All rights reserved.
Lactic acid bacteria contribution to gut microbiota complexity: lights and shadows
Pessione, Enrica
2012-01-01
Lactic Acid Bacteria (LAB) are ancient organisms that cannot biosynthesize functional cytochromes, and cannot get ATP from respiration. Besides sugar fermentation, they evolved electrogenic decarboxylations and ATP-forming deiminations. The right balance between sugar fermentation and decarboxylation/deimination ensures buffered environments thus enabling LAB to survive in human gastric trait and colonize gut. A complex molecular cross-talk between LAB and host exists. LAB moonlight proteins are made in response to gut stimuli and promote bacterial adhesion to mucosa and stimulate immune cells. Similarly, when LAB are present, human enterocytes activate specific gene expression of specific genes only. Furthermore, LAB antagonistic relationships with other microorganisms constitute the basis for their anti-infective role. Histamine and tyramine are LAB bioactive catabolites that act on the CNS, causing hypertension and allergies. Nevertheless, some LAB biosynthesize both gamma-amino-butyrate (GABA), that has relaxing effect on gut smooth muscles, and beta-phenylethylamine, that controls satiety and mood. Since LAB have reduced amino acid biosynthetic abilities, they developed a sophisticated proteolytic system, that is also involved in antihypertensive and opiod peptide generation from milk proteins. Short-chain fatty acids are glycolytic and phosphoketolase end-products, regulating epithelial cell proliferation and differentiation. Nevertheless, they constitute a supplementary energy source for the host, causing weight gain. Human metabolism can also be affected by anabolic LAB products such as conjugated linoleic acids (CLA). Some CLA isomers reduce cancer cell viability and ameliorate insulin resistance, while others lower the HDL/LDL ratio and modify eicosanoid production, with detrimental health effects. A further appreciated LAB feature is the ability to fix selenium into seleno-cysteine. Thus, opening interesting perspectives for their utilization as
Weinberg, Z G; Chen, Y; Volchinski, V; Sela, S; Ogunade, I M; Adesogan, A
2016-07-01
Previous studies have shown that silages treated with lactic acid bacteria (LAB) inoculants enhance ruminants' performance. The objective of the current experiments was to develop an in vitro model to study interactions between LAB silage inoculants and inoculated silages and Escherichia coli (EC) in rumen fluid (RF). Our hypothesis was that some inoculants inhibit EC in RF. For that purpose buffered RF was incubated under anaerobic conditions at 39°C with commercial strains of LAB silage inoculants or with laboratory corn and wheat silages treated with these LAB, an EC strain and with various ruminant feed ingredients. The EC strain was originally isolated from cattle manure and tagged with a plasmid expressing the green fluorescence protein and kanamycin and streptomycin resistance. Results indicate that the LAB or the treated silages did not suppress EC numbers in the RF. When the pH of the RF decreased below 5·0 the EC disappeared. We conclude that both LAB inoculants for silage and EC survived in RF for several days; however, the inoculants and silages treated with such inoculants did not inhibit EC in RF in vitro. Forage crops, silage and hay are initial stages of the food chain for humans. Cattle harbours and sheds enterobacteria regularly, some strains of which are pathogens. These can contaminate forage crops through field fertilization with cattle manure. The objective of this study was to develop an in vitro model to test whether lactic acid bacteria, which are used in silage inoculants, alone or in treated silages can inhibit Escherichia coli in rumen fluid. This study presents safety aspects and it is also part of a broad research effort aimed at finding out how LAB silage inoculants and inoculated silages enhance ruminant performance or exert probiotic effects in ruminants. © 2016 The Society for Applied Microbiology.
Kopf, Matthias; Klähn, Stephan; Scholz, Ingeborg; Hess, Wolfgang R; Voß, Björn
2015-04-22
In all studied organisms, a substantial portion of the transcriptome consists of non-coding RNAs that frequently execute regulatory functions. Here, we have compared the primary transcriptomes of the cyanobacteria Synechocystis sp. PCC 6714 and PCC 6803 under 10 different conditions. These strains share 2854 protein-coding genes and a 16S rRNA identity of 99.4%, indicating their close relatedness. Conserved major transcriptional start sites (TSSs) give rise to non-coding transcripts within the sigB gene, from the 5'UTRs of cmpA and isiA, and 168 loci in antisense orientation. Distinct differences include single nucleotide polymorphisms rendering promoters inactive in one of the strains, e.g., for cmpR and for the asRNA PsbA2R. Based on the genome-wide mapped location, regulation and classification of TSSs, non-coding transcripts were identified as the most dynamic component of the transcriptome. We identified a class of mRNAs that originate by read-through from an sRNA that accumulates as a discrete and abundant transcript while also serving as the 5'UTR. Such an sRNA/mRNA structure, which we name 'actuaton', represents another way for bacteria to remodel their transcriptional network. Our findings support the hypothesis that variations in the non-coding transcriptome constitute a major evolutionary element of inter-strain divergence and capability for physiological adaptation.
Kopf, Matthias; Klähn, Stephan; Scholz, Ingeborg; Hess, Wolfgang R.; Voß, Björn
2015-01-01
In all studied organisms, a substantial portion of the transcriptome consists of non-coding RNAs that frequently execute regulatory functions. Here, we have compared the primary transcriptomes of the cyanobacteria Synechocystis sp. PCC 6714 and PCC 6803 under 10 different conditions. These strains share 2854 protein-coding genes and a 16S rRNA identity of 99.4%, indicating their close relatedness. Conserved major transcriptional start sites (TSSs) give rise to non-coding transcripts within the sigB gene, from the 5′UTRs of cmpA and isiA, and 168 loci in antisense orientation. Distinct differences include single nucleotide polymorphisms rendering promoters inactive in one of the strains, e.g., for cmpR and for the asRNA PsbA2R. Based on the genome-wide mapped location, regulation and classification of TSSs, non-coding transcripts were identified as the most dynamic component of the transcriptome. We identified a class of mRNAs that originate by read-through from an sRNA that accumulates as a discrete and abundant transcript while also serving as the 5′UTR. Such an sRNA/mRNA structure, which we name ‘actuaton’, represents another way for bacteria to remodel their transcriptional network. Our findings support the hypothesis that variations in the non-coding transcriptome constitute a major evolutionary element of inter-strain divergence and capability for physiological adaptation. PMID:25902393
González-Quijano, Génesis Karendash; Dorantes-Alvarez, Lidia; Hernández-Sánchez, Humberto; Jaramillo-Flores, María Eugenia; de Jesús Perea-Flores, María; Vera-Ponce de León, Arturo; Hernández-Rodríguez, César
2014-08-01
The microbiota associated with spontaneous fermentation of vegetables in a saline substrate may represent an important group of bacteria in the food industry. In this work, the lactic acid bacteria (LAB) Weissella cibaria, Lactobacillus plantarum, Lactobacillus paraplantarum, and Leuconostoc citreum were identified by partial 16S rRNA gene sequence analysis. In addition, entophytic bacteria such as Pantoea eucalypti, Pantoea anthophila, Enterobacter cowanii, and Enterobacter asburiae were detected, but they were irrelevant for the fermentation process and were inhibited after 12 h of fermentation when the pH decreased from 6.5 to 4.9. Moreover, 2 species of yeast were isolated and identified as Hanseniaspora pseudoguilliermondii and Kodamaea ohmeri by their partial 26S rRNA gene sequence. The growth of LAB was evaluated at different sodium chloride contents. L. citreum was the most halotolerant species followed by L. plantarum and W. cibaria with a concentration index to obtain a 50% population reduction (IC(50)) of 7.2%, 6.6%, and 5.2%, respectively. Furthermore, the growth of LAB and Escherichia coli O157:H7 was evaluated in the presence of the main phenylpropanoids from chilli peppers such as p-coumaric and ferulic acid. It was determined that LAB can grow in both acids at 4 mM, unlike E. coli O157:H7, whose growth is inhibited in the presence of these acids. © 2014 Institute of Food Technologists®
Biological and Chemical Diversity of Bacteria Associated with a Marine Flatworm.
Lin, Hui-Na; Wang, Kai-Ling; Wu, Ze-Hong; Tian, Ren-Mao; Liu, Guo-Zhu; Xu, Ying
2017-09-01
The aim of this research is to explore the biological and chemical diversity of bacteria associated with a marine flatworm Paraplanocera sp., and to discover the bioactive metabolites from culturable strains. A total of 141 strains of bacteria including 45 strains of actinomycetes and 96 strains of other bacteria were isolated, identified and fermented on a small scale. Bioactive screening (antibacterial and cytotoxic activities) and chemical screening (ultra-performance liquid chromatography-mass spectrometry (UPLC-MS)) yielded several target bacterial strains. Among these strains, the ethyl acetate (EA) crude extract of Streptomyces sp. XY-FW47 fermentation broth showed strong antibacterial activity against methicillin-resistant Staphylococcus aureus ATCC43300 (MRSA ATCC43300) and potent cytotoxic effects on HeLa cells. The UPLC-MS spectral analysis of the crude extract indicated that the strain XY-FW47 could produce a series of geldanamycins (GMs). One new geldanamycin (GM) analog, 4,5-dihydro-17-O-demethylgeldanamycin (1), and three known GMs (2-4) were obtained. All of these compounds were tested for antibacterial, cytotoxic, and antifungal activities, yet only GM (3) showed potent cytotoxic (HeLa cells, EC 50 = 1.12 μg/mL) and antifungal ( Setosphaeria turcica MIC = 2.40 μg/mL) activities. Their structure-activity relationship (SAR) was also preliminarily discussed in this study.
Effects of Bacteria on Artemia franciscana Cultured in Different Gnotobiotic Environments
Marques, Antonio; Dinh, Thi; Ioakeimidis, Christos; Huys, Geert; Swings, Jean; Verstraete, Willy; Dhont, Jean; Sorgeloos, Patrick; Bossier, Peter
2005-01-01
The use of probiotics is receiving considerable attention as an alternative approach to control microbiota in aquaculture farms, especially in hatching facilities. However, application with consistent results is hampered by insufficient information on their modes of action. To investigate whether dead bacteria (allowing investigation of their nutritional effect) or live bacteria (allowing evaluation of their probiotic effect) have any beneficial effect towards Artemia franciscana and, subsequently, if live bacteria have probiotic effects beyond the effects observed with dead bacteria, a model system was employed using gnotobiotic Artemia as a test organism. Nauplii were cultured in the presence of 10 bacterial strains combined with four different major axenic live feeds (two strains of Saccharomyces cerevisiae and two strains of Dunaliella tertiolecta) differing in their nutritional values. In combination with poor- and medium-quality live feeds, dead bacteria exerted a strong effect on Artemia survival but a rather weak or no effect on individual length and constituted a maximum of only 5.9% of the total ash-free dry weight supplied. These effects were reduced or even disappeared when medium- to good-quality major feed sources were used, possibly due to improvements in the health status of Artemia. Some probiotic bacteria, such as GR 8 (Cytophaga spp.), improved (not always significantly) the performance of nauplii beyond the effect observed with dead bacteria, independently of the feed supplied. The present approach can be an excellent system to study the exact mode of action of bacteria, especially if combined with challenge tests or other types of analysis (e.g., transcriptome and proteonomic analysis). PMID:16085818
[Isolation and identification of rumen bacteria for cellulolytic enzyme production].
Aihemaiti, Maierhaba; Zhen, Fan; Li, Yuezhong; Aibaidoula, Gulisimayi; Yimit, Wusiman
2013-05-04
We screened aerobic bacteria with cellulolytic activity from ruminal fluid of sheep, cattle and camel in Xinjiang. Fresh ruminal fluid was inoculated on sterilized sodium carboxymethylcellulose agar plates. Highly cellulolytic aerobic bacteria were screened out by using Congo red staining and liquid secondary screening culture media. The combination of morphological and biochemical test with 16SrDNA sequence analysis were used to classify the strains. Enzymatic activities of four strains with strong cellulose-decomposing abilities were studied under different culture conditions. Out 84 isolated cellulolytic strains, 40 exhibited strong abilities in decomposing cellulose. They are including 37 Gram-negative isolates and 3 Gram-positive strains. Identification of these 40 strains shows that they belong to 11 species of 6 genera, 16 strains in Stenotrophomonas maltophilia, 10 Ochrobactrum, 5 Sphingobacterium, 3 Microbacterium, 3 Paracoccus and 2 Pseudomonas. The results of the enzymatic studies of four strains with strong cellulolytic abilities indicates that the strains have the best enzyme producing property when straw powder was chosen as the carbon source; the pH at 5.5 -6.0 and temperature at 37 degrees C. The strains with highly cellulolytic abilities isolated from ruminal fluid show strong abilities in cellulose decomposition.
Yang, Zhiwei; Zhou, Feng; Ji, Baoping; Li, Bo; Luo, Yangchao; Yang, Li; Li, Tao
2010-01-01
Gluconacetobacter sp. A4 (G. sp. A4), which had strong ability to produce d-saccharic acid 1, 4 lactone (DSL), was the key functional bacteria isolated from the kombucha preserved. This paper investigated the interaction between G. sp. A4 and ten different strains of lactic acid bacteria (LAB) obtained from kefir. The result suggested that the LAB promoted DSL production of G. sp. A4 to different extents, ranging from 4.86% to 86.70%. Symbiosis between G. sp. A4 and LAB was studied. LAB's metabolites, xylitol, and acetic acid, were utilized by G. sp. A4, and it promoted the growth of G. sp. A4 and yield of DSL. Therefore, in developing starter cultures for kombucha fermentation process, a mixed flora of LAB and G. sp. A4 would be the optimal combination.
Surveillance of multidrug resistant uropathogenic bacteria in hospitalized patients in Indian
Mishra, Monali Priyadarsini; Debata, Nagen Kumar; Padhy, Rabindra Nath
2013-01-01
Objective To record surveillance, antibiotic resistance of uropathogens of hospitalized patients over a period of 18 months. Methods Urine samples from wards and cabins were used for isolating urinary tract infection (UTI)-causing bacteria that were cultured on suitable selective media and identified by biochemical tests; and their antibiograms were ascertained by Kirby-Bauer's disc diffusion method, in each 6-month interval of the study period, using 18 antibiotics of five different classes. Results From wards and cabins, 1 245 samples were collected, from which 996 strains of bacteria belonging to 11 species were isolated, during April 2011 to September 2012. Two Gram-positive, Staphylococcus aureus (S. aureus) and Enterococcus faecalis (E. faecalis), and nine Gram-negative bacteria, Acinetobacter baumannii, Citrobacter sp., Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Klebsiella oxytoca, Proteus mirabilis, Proteus vulgaris and Pseudomonas aeruginosa were isolated. Both S. aureus and E. faecalis were vancomycin resistant, and resistant-strains of all pathogens increased in each 6-month period of study. Particularly, all Gram-negatives were resistant to nitrofurantoin and co-trimoxazole, the most preferred antibiotics of empiric therapy for UTI. Conclusions Antibiograms of 11 UTI-causing bacteria recorded in this study indicated moderately higher numbers of strains resistant to each antibiotic studied, generating the fear of precipitating fervent episodes in public health particularly with bacteria, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae and S. aureus. Moreover, vancomycin resistance in strains of S. aureus and E. faecalis is a matter of concern. PMID:23620859
Adhesion of Biodegradative Anaerobic Bacteria to Solid Surfaces
van Schie, Paula M.; Fletcher, Madilyn
1999-01-01
In order to exploit the ability of anaerobic bacteria to degrade certain contaminants for bioremediation of polluted subsurface environments, we need to understand the mechanisms by which such bacteria partition between aqueous and solid phases, as well as the environmental conditions that influence partitioning. We studied four strictly anaerobic bacteria, Desulfomonile tiedjei, Syntrophomonas wolfei, Syntrophobacter wolinii, and Desulfovibrio sp. strain G11, which theoretically together can constitute a tetrachloroethylene- and trichloroethylene-dechlorinating consortium. Adhesion of these organisms was evaluated by microscopic determination of the numbers of cells that attached to glass coverslips exposed to cell suspensions under anaerobic conditions. We studied the effects of the growth phase of the organisms on adhesion, as well as the influence of electrostatic and hydrophobic properties of the substratum. Results indicate that S. wolfei adheres in considerably higher numbers to glass surfaces than the other three organisms. Starvation greatly decreases adhesion of S. wolfei and Desulfovibrio sp. strain G11 but seems to have less of an effect on the adhesion of the other bacteria. The presence of Fe3+ on the substratum, which would be electropositive, significantly increased the adhesion of S. wolfei, whereas the presence of silicon hydrophobic groups decreased the numbers of attached cells of all species. Measurements of transport of cells through hydrophobic-interaction and electrostatic-interaction columns indicated that all four species had negatively charged cell surfaces and that D. tiedjei and Desulfovibrio sp. strain G11 possessed some hydrophobic cell surface properties. These findings are an early step toward understanding the dynamic attachment of anaerobic bacteria in anoxic environments. PMID:10543826
Probing minority population of antibiotic-resistant bacteria.
Huang, Tianxun; Zheng, Yan; Yan, Ya; Yang, Lingling; Yao, Yihui; Zheng, Jiaxin; Wu, Lina; Wang, Xu; Chen, Yuqing; Xing, Jinchun; Yan, Xiaomei
2016-06-15
The evolution and spread of antibiotic-resistant pathogens has become a major threat to public health. Advanced tools are urgently needed to quickly diagnose antibiotic-resistant infections to initiate appropriate treatment. Here we report the development of a highly sensitive flow cytometric method to probe minority population of antibiotic-resistant bacteria via single cell detection. Monoclonal antibody against TEM-1 β-lactamase and Alexa Fluor 488-conjugated secondary antibody were used to selectively label resistant bacteria green, and nucleic acid dye SYTO 62 was used to stain all the bacteria red. A laboratory-built high sensitivity flow cytometer (HSFCM) was applied to simultaneously detect the side scatter and dual-color fluorescence signals of single bacteria. By using E. coli JM109/pUC19 and E. coli JM109 as the model systems for antibiotic-resistant and antibiotic-susceptible bacteria, respectively, as low as 0.1% of antibiotic-resistant bacteria were accurately quantified. By monitoring the dynamic population change of a bacterial culture with the administration of antibiotics, we confirmed that under the antimicrobial pressure, the original low population of antibiotic-resistant bacteria outcompeted susceptible strains and became the dominant population after 5hours of growth. Detection of antibiotic-resistant infection in clinical urine samples was achieved without cultivation, and the bacterial load of susceptible and resistant strains can be faithfully quantified. Overall, the HSFCM-based quantitative method provides a powerful tool for the fundamental studies of antibiotic resistance and holds the potential to provide rapid and precise guidance in clinical therapies. Copyright © 2016 Elsevier B.V. All rights reserved.
[Application of anaerobic bacteria detection in oral and maxillofacial infection].
Bao, Zhen-ying; Lin, Qin; Meng, Yan-hong; He, Chun; Su, Jia-zeng; Peng, Xin
2016-02-18
To investigate the distribution and drug resistance of anaerobic bacteria in the patients with oral and maxillofacial infection. Aerobic and anaerobic bacteria cultures from 61 specimens of pus from the patients with oral and maxillofacial infection in the Department of Oral and Maxillofacial Surgery, Peking University School of Stomatology were identified. The culture type was evaluated by API 20A kit and drug resistance test was performed by Etest method. The clinical data and antibacterial agents for the treatment of the 61 cases were collected, and the final outcomes were recorded. The bacteria cultures were isolated from all the specimens, with aerobic bacteria only in 6 cases (9.8%), anaerobic bacteria only in 7 cases (11.5%), and both aerobic and anaerobic bacteria in 48 cases (78.7%). There were 55 infected cases (90.2%) with anaerobic bacteria, and 81 anaerobic bacteria stains were isolated. The highest bacteria isolation rate of Gram positive anaerobic bacteria could be found in Peptostreptococcus, Bifidobacterium and Pemphigus propionibacterium. No cefoxitin, amoxicillin/carat acid resistant strain was detected in the above three Gram positive anaerobic bacteria. The highest bacteria isolation rate of Gram negative anaerobic bacteria could be detected in Porphyromonas and Prevotella. No metronidazole, cefoxitin, amoxicillin/carat acid resistant strain was found in the two Gram negative anaerobic bacteria. In the study, 48 patients with oral and maxillofacial infection were treated according to the results of drug resistance testing, and the clinical cure rate was 81.3%. Mixed aerobic and anaerobic bacteria cultures are very common in most oral and maxillofacial infection patients. Anaerobic bacteria culture and drug resistance testing play an important role in clinical treatment.
Krzymińska, Sylwia; Szczuka, Ewa; Kaznowski, Adam
2012-11-01
The aim of this study was to investigate the interaction of Staphylococcus haemolyticus strains with a macrophage cell line. Infection with the strains resulted in macrophage injury. All strains exhibited cytotoxic effects towards J774 cells. Moreover, the bacteria triggered apoptosis of the cells. The lowest apoptotic index did not exceed 21 %, whereas the highest reached 70 % at 24 h and 85 % at 48 h after infection. Incubation with the bacteria caused loss of mitochondrial membrane potential (ΔΨm) in macrophages. The pro-apoptotic activity of the strains was blocked by a pan-caspase inhibitor z-VAD-fmk, indicating the involvement of caspases in the bacteria-mediated cell death. We observed that the induction of macrophage apoptosis could constitute an important mechanism of pathogenesis by which S. haemolyticus strains evade host immune defences and cause disease.
Suleiman, Marcel; Zecher, Karsten; Yücel, Onur; Jagmann, Nina; Philipp, Bodo
2016-12-15
Methylamines occur ubiquitously in the oceans and can serve as carbon, nitrogen, and energy sources for heterotrophic bacteria from different phylogenetic groups within the marine bacterioplankton. Diatoms, which constitute a large part of the marine phytoplankton, are believed to be incapable of using methylamines as a nitrogen source. As diatoms are typically associated with heterotrophic bacteria, the hypothesis came up that methylotrophic bacteria may provide ammonium to diatoms by degradation of methylamines. This hypothesis was investigated with the diatom Phaeodactylum tricornutum and monomethylamine (MMA) as the substrate. Bacteria supporting photoautotrophic growth of P. tricornutum with MMA as the sole nitrogen source could readily be isolated from seawater. Two strains, Donghicola sp. strain KarMa, which harbored genes for both monomethylamine dehydrogenase and the N methylglutamate pathway, and Methylophaga sp. strain M1, which catalyzed MMA oxidation by MMA dehydrogenase, were selected for further characterization. While strain M1 grew with MMA as the sole substrate, strain KarMa could utilize MMA as a nitrogen source only when, e.g., glucose was provided as a carbon source. With both strains, release of ammonium was detected during MMA utilization. In coculture with P. tricornutum, strain KarMa supported photoautotrophic growth with 2 mM MMA to the same extent as with the equimolar amount of NH 4 Cl. In coculture with strain M1, photoautotrophic growth of P. tricornutum was also supported, but to a much lower degree than by strain KarMa. This proof-of-principle study with a synthetic microbial community suggests that interkingdom cross-feeding of ammonium from methylamine-degrading bacteria is a contribution to phytoplankton growth which has been overlooked so far. Interactions between diatoms and heterotrophic bacteria are important for marine carbon cycling. In this study, a novel interaction is described. Bacteria able to degrade monomethylamine
Suleiman, Marcel; Zecher, Karsten; Yücel, Onur; Jagmann, Nina
2016-01-01
ABSTRACT Methylamines occur ubiquitously in the oceans and can serve as carbon, nitrogen, and energy sources for heterotrophic bacteria from different phylogenetic groups within the marine bacterioplankton. Diatoms, which constitute a large part of the marine phytoplankton, are believed to be incapable of using methylamines as a nitrogen source. As diatoms are typically associated with heterotrophic bacteria, the hypothesis came up that methylotrophic bacteria may provide ammonium to diatoms by degradation of methylamines. This hypothesis was investigated with the diatom Phaeodactylum tricornutum and monomethylamine (MMA) as the substrate. Bacteria supporting photoautotrophic growth of P. tricornutum with MMA as the sole nitrogen source could readily be isolated from seawater. Two strains, Donghicola sp. strain KarMa, which harbored genes for both monomethylamine dehydrogenase and the N methylglutamate pathway, and Methylophaga sp. strain M1, which catalyzed MMA oxidation by MMA dehydrogenase, were selected for further characterization. While strain M1 grew with MMA as the sole substrate, strain KarMa could utilize MMA as a nitrogen source only when, e.g., glucose was provided as a carbon source. With both strains, release of ammonium was detected during MMA utilization. In coculture with P. tricornutum, strain KarMa supported photoautotrophic growth with 2 mM MMA to the same extent as with the equimolar amount of NH4Cl. In coculture with strain M1, photoautotrophic growth of P. tricornutum was also supported, but to a much lower degree than by strain KarMa. This proof-of-principle study with a synthetic microbial community suggests that interkingdom cross-feeding of ammonium from methylamine-degrading bacteria is a contribution to phytoplankton growth which has been overlooked so far. IMPORTANCE Interactions between diatoms and heterotrophic bacteria are important for marine carbon cycling. In this study, a novel interaction is described. Bacteria able to degrade
Antigenotoxic properties of lactic acid bacteria in the S. typhimurium mutagenicity assay.
Pool-Zobel, B L; Münzner, R; Holzapfel, W H
1993-01-01
A high percentage of human tumors is reported to be related to dietary habits. One way to improve the nutritional impact is to increase the intake of protective factors, such as inhibitors of DNA damage and other types of anticarcinogens. Specific strains of lactic acid bacteria used to ferment milk are promising candidates that may be antimutagenic and anticarcinogenic. We have studied the antimutagenicity of 10 isolated strains of beneficial lactic acid bacteria. Four types of fermented milk products were also studied for their protective properties. The effect of these bacteria on the yield of revertants induced by nitrosated beef extract was investigated in the Salmonella typhimurium mutagenicity assay. Eight of 10 isolated Lactobacillus strains reduced the yield of his+ revertants almost back to the levels of the untreated controls. Different fermented fresh yogurts containing viable bacteria (probably Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus or Lactobacillus acidophilus and Bifidobacteria) showed protective effects as well. The degree of suppressing revertants was independent of the yogurt's fat content. In contrast, yogurt products that had been heat treated were not inhibitory. The other fresh fermented milk products (e.g., buttermilk, kefir, and "Dickmilch") were not antimutagenic in this study. The results imply that some bacteria used in milk processing have an antimutagenic potential and that this property is specific for the bacterial strain.
Sivolodsky, E P
2015-01-01
Development of a selective-differential nutrient medium for isolation of Shewanella genus bacteria. 73 strains of Shewanella bacteria (S. algae--3, S. baltica--26, S. putrefaciens--44) and 80 strains of 22 other bacteria genera were used. Shewanella species were identified by methods and criteria proposed by Nozue H. et al., 1992; Khashe S. et al., 1998. Nutrient media "Shewanella IRHLS Agar" for shewanella isolation was developed. Medium selective factors: irgazan DP-300 (I). 0.14-0.2 g/l and rifampicin (R) 0.0005-0.001 g/l. Shevanella colonies were detected by the production of hydrogen sulfide (H), lipase presence (L), lack of sorbitol fermentation (S). The medium suppressed the growth of hydrogen sulfide producers (Salmonella, Proteus) and blocked hydrogen sulfide production by Citrobacter. Growth of Escherichia, Enterobacter, Klebsiella, Shigella, Staphylococcus, Bacillus was also suppressed, Analytical sensitivity of the medium was 1-2 CFU/ml for Shewanella and Stenotrophomonas, Aerombnas, Serratia genera bacteria. 72 strains of Shewanella were isolated from water of Neva river in this medium, 91.7 ± 3.2% of those produced H2S. 1 strain of S. algae was isolated from clinical material. The developed media allows to use it in a complex for Stenotrophomo- nas sp., Aeromonas sp., Serratia sp., Citrobactersp. and Shewanella bacteria isolation.
Physiological characteristics of bacteria isolated from water brines within permafrost
NASA Astrophysics Data System (ADS)
Shcherbakova, V.; Rivkina, E.; Laurinavichuis, K.; Pecheritsina, S.; Gilichinsky, D.
2004-01-01
In the Arctic there are lenses of overcooled water brines (cryopegs) sandwiched within permafrost marine sediments 100 120 thousand years old. We have investigated the physiological properties of the pure cultures of anaerobic Clostridium sp. strain 14D1 and two strains of aerobic bacteria Psychrobacter sp. isolated from these cryopegs. The structural and physiological characteristics of new bacteria from water brines have shown their ability to survive and develop under harsh conditions, such as subzero temperatures and high salinity.
Bacteria Mediate Methylation of Iodine in Marine and Terrestrial Environments
Amachi, Seigo; Kamagata, Yoichi; Kanagawa, Takahiro; Muramatsu, Yasuyuki
2001-01-01
Methyl iodide (CH3I) plays an important role in the natural iodine cycle and participates in atmospheric ozone destruction. However, the main source of this compound in nature is still unclear. Here we report that a wide variety of bacteria including terrestrial and marine bacteria are capable of methylating the environmental level of iodide (0.1 μM). Of the strains tested, Rhizobium sp. strain MRCD 19 was chosen for further analysis, and it was found that the cell extract catalyzed the methylation of iodide with S-adenosyl-l-methionine as the methyl donor. These results strongly indicate that bacteria contribute to iodine transfer from the terrestrial and marine ecosystems into the atmosphere. PMID:11375186
Isolation of Lightning-Competent Soil Bacteria
Cérémonie, Hélène; Buret, François; Simonet, Pascal; Vogel, Timothy M.
2004-01-01
Artificial transformation is typically performed in the laboratory by using either a chemical (CaCl2) or an electrical (electroporation) method. However, laboratory-scale lightning has been shown recently to electrotransform Escherichia coli strain DH10B in soil. In this paper, we report on the isolation of two “lightning-competent” soil bacteria after direct electroporation of the Nycodenz bacterial ring extracted from prairie soil in the presence of the pBHCRec plasmid (Tcr, Spr, Smr). The electrotransformability of the isolated bacteria was measured both in vitro (by electroporation cuvette) and in situ (by lightning in soil microcosm) and then compared to those of E. coli DH10B and Pseudomonas fluorescens C7R12. The electrotransformation frequencies measured reached 10−3 to 10−4 by electroporation and 10−4 to 10−5 by simulated lightning, while no transformation was observed in the absence of electrical current. Two of the isolated lightning-competent soil bacteria were identified as Pseudomonas sp. strains. PMID:15466589
Genetics of Lactic Acid Bacteria
NASA Astrophysics Data System (ADS)
Zagorec, Monique; Anba-Mondoloni, Jamila; Coq, Anne-Marie Crutz-Le; Champomier-Vergès, Marie-Christine
Many meat (or fish) products, obtained by the fermentation of meat originating from various animals by the flora that naturally contaminates it, are part of the human diet since millenaries. Historically, the use of bacteria as starters for the fermentation of meat, to produce dry sausages, was thus performed empirically through the endogenous micro-biota, then, by a volunteer addition of starters, often performed by back-slopping, without knowing precisely the microbial species involved. It is only since about 50 years that well defined bacterial cultures have been used as starters for the fermentation of dry sausages. Nowadays, the indigenous micro-biota of fermented meat products is well identified, and the literature is rich of reports on the identification of lactic acid bacteria (LAB) present in many traditional fermented products from various geographical origin, obtained without the addition of commercial starters (See Talon, Leroy, & Lebert, 2007, and references therein).
NASA Astrophysics Data System (ADS)
Gordillo-Delgado, F.; Marín, E.; Calderón, A.
2013-09-01
The effect of titanium dioxide photocatalysis against bacteria that are dangerous for human health has been investigated in the past, suggesting the possibility of using a specific behavior for each microorganism during this process for its discrimination. In this study, the behavior of some plants’ growth promoting bacteria ( Burkholderia unamae (Strain MTI 641), Acetobacter diazotrophicus (Strain PAl 5T), A. diazotrophicus (Strain CFN-Cf 52), and B. unamae (Strain TATl-371)) interacting with light and bactericidal titanium dioxide films have been analyzed using the photoacoustic technique. The monitoring of these interactions shows particular characteristics that could serve for identifying these species.
Lactobacillus salivarius: bacteriocin and probiotic activity.
Messaoudi, S; Manai, M; Kergourlay, G; Prévost, H; Connil, N; Chobert, J-M; Dousset, X
2013-12-01
Lactic acid bacteria (LAB) antimicrobial peptides typically exhibit antibacterial activity against food-borne pathogens, as well as spoilage bacteria. Therefore, they have attracted the greatest attention as tools for food biopreservation. In some countries LAB are already extensively used as probiotics in food processing and preservation. LAB derived bacteriocins have been utilized as oral, topical antibiotics or disinfectants. Lactobacillus salivarius is a promising probiotic candidate commonly isolated from human, porcine, and avian gastrointestinal tracts (GIT), many of which are producers of unmodified bacteriocins of sub-classes IIa, IIb and IId. It is a well-characterized bacteriocin producer and probiotic organism. Bacteriocins may facilitate the introduction of a producer into an established niche, directly inhibit the invasion of competing strains or pathogens, or modulate the composition of the microbiota and influence the host immune system. This review gives an up-to-date overview of all L. salivarius strains, isolated from different origins, known as bacteriocin producing and/or potential probiotic. Copyright © 2013 Elsevier Ltd. All rights reserved.
Biodiversity analysis by polyphasic study of marine bacteria associated with biocorrosion phenomena.
Boudaud, N; Coton, M; Coton, E; Pineau, S; Travert, J; Amiel, C
2010-07-01
A polyphasic approach was used to study the biodiversity bacteria associated with biocorrosion processes, in particular sulfate-reducing bacteria (SRB) and thiosulfate-reducing bacteria (TRB) which are described to be particularly aggressive towards metallic materials, notably via hydrogen sulfide release. To study this particular flora, an infrared spectra library of 22 SRB and TRB collection strains were created using a Common Minimum Medium (CMM) developed during this study and standardized culture conditions. The CMM proved its ability to allow for growth of both SRB and TRB strains. These sulfurogen collection strains were clearly discriminated and differentiated at the genus level by fourier transform infrared (FT-IR) spectroscopy. In a second step, infrared spectra of isolates, recovered from biofilms formed on carbon steel coupons immersed for 1 year in three different French harbour areas, were compared to the infrared reference spectra library. In parallel, molecular methods (M13-PCR and 16S rRNA gene sequencing) were used to qualitatively evaluate the intra- and inter-species genetic diversity of biofilm isolates. The biodiversity study indicated that strains belonging to the Vibrio genus were the dominant population; strains belonging to the Desulfovibrio genus (SRB) and Peptostreptococcaceae were also identified. Overall, the combination of the FT-IR spectroscopy and molecular approaches allowed for the taxonomic and ecological study of a bacterial flora, cultivated on CMM, associated with microbiology-induced corrosion (MIC) processes. Via the use of the CMM medium, the culture of marine bacteria (including both SRB and TRB bacteria) was allowed, and the implication of nonsulforogen bacteria in MIC was observed. Their involvement in the biocorrosion phenomena will have to be studied and taken into account in the future. © 2009 The Authors. Journal compilation © 2009 The Society for Applied Microbiology.
Rongies, Witold; Wultańska, Dorota; Kot, Katarzyna; Bogusz, Aleksandra; Rongies, Magdalena; Świercz, Paweł; Swierszcz, Paweł; Lewandowska, Monika; Cholewińska, Grazyna; Meisel-Mikołajczyk, Felicja
2011-01-01
Infections in human body caused by various microbes are a significant problem in modern medicine. Special attention is put to infections of wounds, which are a significant threat to the life of patients. Attempts to treat these wounds base mainly on the application of various chemical preparations (locally) and systematic antibiotic treatment. UV radiation, because of its anti-bacterial activity, appear a complementary issue in therapy. AIM OF THE SURVEY: The aim of this study was an examination of the sensitivity of bacteria strains isolated from patients hospitalised in the Warsaw Medical University clinics, and prove that antibiotics and operation of UV B and C radiation with Endolamp 474 may become a complementary or alternative method of treatment. The study used 65 strains grown aerobically (15 strains of Escherichia coli, 20 strains of Pseudomonas aeruginosa, 15 strains of Staphylococcus aureus, 15 strains of Streptococcus and Enterococcus sp). The same strains were planted on different excipients and were subjected to UV radiation using Endolamp 474. Correctly prepared strains were radiated from a 25 cm distance in various durations (from 5 seconds to 105 seconds). As a result of UV irradiation of microorganisms studied B and C using 474 Endolampy received varied, but the great sensitivity to the effects of this radiation, in all tested bacterial strains. UV radiation on microorganisms requires further study, also in vivo.
[Biodiversity of phosphate-dissolving and plant growth--promoting endophytic bacteria of two crops].
Huang, Jing; Sheng, Xiafang; He, Linyan
2010-06-01
We isolated and characterized phosphate-dissolving endophytic bacteria from two commonly cultivated crops. Phosphate-dissolving endophytic bacteria were isolated by plating and screening from interior tissues of rape and maize plants on NBRIP medium with tricalcium phosphate as sole phosphate source. Bacteria were characterized regarding characteristics that may be relevant for a beneficial plant-microbe interaction-indoleacetic acid, siderophore and 1-aminocyclopropane-1-carboxylic acid deaminase production,and further classified by restriction analysis of 16S rDNA. Eleven typical strains were identified by 16S rDNA sequence analysis. Thirty-two phosphate-dissolving endophytic bacteria were isolated from maize and rape plants and classified by restriction analysis of 16S rDNA in 8 different taxonomic groups at the similarity level of 76%. All the isolates could release phosphate from tricalcium phosphate and decrease the pH of the medium. The maximum phosphate content (537.6 mg/L) in the solution was obtained with strain M1L5. Thirteen isolates isolated from rape produced indoleacetic acid and siderophore, 68.4% and 63.2% of the strains isolated from maize produced indoleacetic acid and siderophore,respectively. 63.2% of the strains isolated from maize were able to grow on 1-aminocyclopropane-1-carboxylic acid as the sole nitrogen source. The eleven strains belonged to five different genera including Pantoea, Pseudomonas, Burkholderia, Acinetobacter and Ralstonia. Phosphate-dissolving endophytic bacteria isolated from rape and maize plants have abundant characteristics relative to promoting plant growth and genetic diversity.
EVALUATION OF THE TEA TREE OIL ACTIVITY TO ANAEROBIC BACTERIA--IN VITRO STUDY.
Ziółkowska-Klinkosz, Marta; Kedzia, Anna; Meissner, Hhenry O; Kedzia, Andrzej W
2016-01-01
The study of the sensitivity to tea tree oil (Australian Company TTD International Pty. Ltd. Sydney) was carried out on 193 strains of anaerobic bacteria isolated from patients with various infections within the oral cavity and respiratory tracts. The susceptibility (MIC) of anaerobes was determined by means of plate dilution technique in Brucella agar supplemented with 5% defibrinated sheep blood, menadione and hemin. Inoculum contained 10(5) CFU per spot was cultured with Steers replicator upon the surface of agar with various tea tree oil concentrations or without oil (anaerobes growth control). Incubation the plates was performed in anaerobic jars under anaerobic conditions at 37 degrees C for 48 h. MIC was defined as the lowest concentrations of the essential oil completely inhibiting growth of anaerobic bacteria. Test results indicate, that among Gram-negative bacteria the most sensitive to essential oil were strains of Veillonella and Porphyromonas species. Essential oil in low concentrations (MIC in the range of = 0.12 - 0.5 mg/mL) inhibited growth of accordingly 80% and 68% strains. The least sensitive were strains of the genus Tannerella, Parabacteroides and Dialister (MIC 1.0 - 2.0 mg/mL). In the case of Gram-positive anaerobic bacteria the tea tree oil was the most active to strains of cocci of the genus Anaerococcus and Ruminococcus (MIC in range = 0.12 - 0.5 mg/mL) or strains of rods of the genus Eubacterium and Eggerthella (MIC = 0.25 mg/mL). Among Gram-positive rods the least sensitive were the strains of the genus Bifidobacterium ( MIC = 2.0 mg/mL). The tea tree oil was more active to Gram-positive than to Gram-negative anaerobic bacteria.
Genetic and physiological interactions in the amoeba-bacteria symbiosis.
Jeon, Kwang W
2004-01-01
Amoebae of the xD strain of Amoeba proteus that arose from the D strain by spontaneous infection of Legionella-like X-bacteria are now dependent on their symbionts for survival. Each xD amoeba contains about 42,000 symbionts within symbiosomes, and established xD amoebae die if their symbionts are removed. Thus, harmful infective bacteria changed into necessary cell components. As a result of harboring X-bacteria. xD amoebae exhibit various physiological and genetic characteristics that are different from those of symbiont-free D amoebae. One of the recent findings is that bacterial symbionts control the expression of a host's house-keeping gene. Thus, the expression of the normal amoeba sams gene (sams1) encoding one form of S-adenosylmethionine synthetase is switched to that of sams2 by endosymbiotic X-bacteria. Possible mechanisms for the switching of sams genes brought about by endosymbionts and its significance are discussed.
NASA Astrophysics Data System (ADS)
Mohottala, Hashini
2014-03-01
The general student population enrolled in any college level class is highly diverse. An increasing number of ``nontraditional'' students return to college and most of these students follow distance learning degree programs while engaging in their other commitments, work and family. However, those students tend to avoid taking science courses with labs, mostly because of the incapability of remotely completing the lab components in such courses. In order to address this issue, we have come across a method where introductory level physics labs can be taught remotely. In this process a lab kit with the critical lab components that can be easily accessible are conveniently packed into a box and distributed among students at the beginning of the semester. Once the students are given the apparatus they perform the experiments at home and gather data All communications with reference to the lab was done through an interactive user-friendly webpage - Wikispaces (WikiS). Students who create pages on WikiS can submit their lab write-ups, embed videos of the experiments they perform, post pictures and direct questions to the lab instructor. The students who are enrolled in the same lab can interact with each other through WikiS to discuss labs and even get assistance.
Single-step ethanol production from lignocellulose using novel extremely thermophilic bacteria.
Svetlitchnyi, Vitali A; Kensch, Oliver; Falkenhan, Doris A; Korseska, Svenja G; Lippert, Nadine; Prinz, Melanie; Sassi, Jamaleddine; Schickor, Anke; Curvers, Simon
2013-02-28
Consolidated bioprocessing (CBP) of lignocellulosic biomass to ethanol using thermophilic bacteria provides a promising solution for efficient lignocellulose conversion without the need for additional cellulolytic enzymes. Most studies on the thermophilic CBP concentrate on co-cultivation of the thermophilic cellulolytic bacterium Clostridium thermocellum with non-cellulolytic thermophilic anaerobes at temperatures of 55°C-60°C. We have specifically screened for cellulolytic bacteria growing at temperatures >70°C to enable direct conversion of lignocellulosic materials into ethanol. Seven new strains of extremely thermophilic anaerobic cellulolytic bacteria of the genus Caldicellulosiruptor and eight new strains of extremely thermophilic xylanolytic/saccharolytic bacteria of the genus Thermoanaerobacter isolated from environmental samples exhibited fast growth at 72°C, extensive lignocellulose degradation and high yield ethanol production on cellulose and pretreated lignocellulosic biomass. Monocultures of Caldicellulosiruptor strains degraded up to 89-97% of the cellulose and hemicellulose polymers in pretreated biomass and produced up to 72 mM ethanol on cellulose without addition of exogenous enzymes. In dual co-cultures of Caldicellulosiruptor strains with Thermoanaerobacter strains the ethanol concentrations rose 2- to 8.2-fold compared to cellulolytic monocultures. A co-culture of Caldicellulosiruptor DIB 087C and Thermoanaerobacter DIB 097X was particularly effective in the conversion of cellulose to ethanol, ethanol comprising 34.8 mol% of the total organic products. In contrast, a co-culture of Caldicellulosiruptor saccharolyticus DSM 8903 and Thermoanaerobacter mathranii subsp. mathranii DSM 11426 produced only low amounts of ethanol. The newly discovered Caldicellulosiruptor sp. strain DIB 004C was capable of producing unexpectedly large amounts of ethanol from lignocellulose in fermentors. The established co-cultures of new Caldicellulosiruptor
Kaškonienė, Vilma; Stankevičius, Mantas; Bimbiraitė-Survilienė, Kristina; Naujokaitytė, Gintarė; Šernienė, Loreta; Mulkytė, Kristina; Malakauskas, Mindaugas; Maruška, Audrius
2017-02-01
The scientific interest for the search of natural means of microbial inhibitors has not faded for several years. A search of natural antibiotics, so-called bacteriocins which are produced by lactic acid bacteria (LAB), gains a huge attention of the scientists in the last century, in order to reduce the usage of synthetic food additives. Pure bacteriocins with wide spectra of antibacterial activity are promising among the natural biopreservatives. The usage of bacteriocin(s) producing LAB as starter culture for the fermentation of some food products, in order to increase their shelf-life, when synthetic preservatives are not allowable, is also possible. There are a lot of studies focusing on the isolation of new bacteriocins from traditional fermented food, dairy products and other foods or sometimes even from unusual non-food matrices. Bacteriocins producing bacteria have been isolated from different sources with the different antibacterial activity against food-borne microorganisms. This review covers the classification of bacteriocins, diversity of sources of bacteriocin(s) producing LAB, antibacterial spectra of isolated bacteriocins and analytical methods for the bacteriocin purification and analysis within the last 15 years.
Isolation, identification and characterization of lignin-degrading bacteria from Qinling, China.
Yang, C-X; Wang, T; Gao, L-N; Yin, H-J; Lü, X
2017-12-01
Lignin is an aromatic heteropolymer forming a physical barrier and it is a big challenge in biomass utilization. This paper first investigated lignin-degradation bacteria from rotten wood in Qinling Mountain. Nineteen potential strains were selected and ligninolytic enzyme activities were determined over 84 h. Strains that had higher enzyme activities were selected. Further, the biodegradation of wheat straw lignin and alkali lignin was evaluated indicating that Burkholderia sp. H1 had the highest capability. It was confirmed by gel permeation chromatography and field emission scanning electron microscope that alkali lignin was depolymerized into small fragments. The degraded products were analysed using gas chromatography-mass spectrometry. The total ion chromatograph of products treated for 7 days showed the formation of aromatic compounds, an important intermediate from lignin degradation. Interestingly, they disappeared in 15 days while the aldehyde and ester compounds increased. The results suggest that the lignin-degrading bacteria are abundant in rotten wood and strain H1 has high potential to break down lignin. The diversity of lignin-degrading bacteria in Qinling Mountain is revealed. The study of Burkholderia sp. H1 expands the range of bacteria for lignin degradation and provides novel bacteria for application to lignocellulosic biomass. © 2017 The Society for Applied Microbiology.
Co-culturing Effects of Coexisting Bacteria on Wood Degradation by Trametes versicolor.
Kamei, Ichiro
2017-01-01
White-rot fungi are the main decomposers of wood cell-wall polymer in forest ecosystems. Little is known, however, about the interactions between white-rot fungi and other coexisting microorganisms in decayed wood. A white-rot fungus, Trametes versicolor strain TN6F, was isolated from a fruit body, and 44 strains of coexisting cultivable bacteria were isolated from its substrate, natural white rot-decayed wood. The effects of these bacteria on fungal growth were examined by an in vitro confrontation growth assay. Among the isolates, nine bacterial strains inhibited the growth of strain TN6F, while 35 strains did not affect the growth of TN6F. However, when co-cultured with strain TN6F on wood powder, many bacterial strains promoted the weight loss of the substrate. A subsequent chemical composition analysis showed that co-culturing accelerated delignification. Higher laccase activity was detected when strain TN6F was co-cultured on wood powder medium with bacterial strains TN6W-26 or TN6W-27. These results indicate that some bacterial strains might promote wood degradation.
Structurally altered capsular polysaccharides produced by mutant bacteria
NASA Technical Reports Server (NTRS)
Petersen, Gene R. (Inventor); Kern, Roger G. (Inventor); Richards, Gil F. (Inventor)
1995-01-01
Structurally altered capsular polysaccharides are produced by mutant bacteria. These polysaccharides are isolated by selecting a wild type bacterial strain and a phage producing degradative enzymes that have substrate specificity for the capsular polysaccharides produced by the wild type bacteria. Phage-resistant mutants producing capsular polysaccharides are selected and the structurally altered capsular polysaccharide is isolated therefrom.
KAMIYA, Seitaro; OGASAWARA, Masayoshi; ARAKAWA, Masayuki; HAGIMORI, Masayori
2013-01-01
Thrombosis is characterized by congenital and acquired procatarxis. Lactic acid bacteria-fermented soybean milk products (FS-LAB) inhibit hepatic lipid accumulation and prevent atherosclerotic plaque formation. However, the therapeutic efficacy of FS-LAB against thrombosis has yet to be investigated. In this study, FS-LAB were administered subcutaneously into the tails of rats, with the subsequent intravenous administration of κ-carrageenan 12 hr after the initial injection. In general, administration of κ-carrageenan induces thrombosis. The length of the infarcted tail regions was significantly shorter in the rats administered a single-fold or double-fold concentration of the FS-LAB solution compared with the region in control rats. Therefore, FS-LAB exhibited significant antithrombotic effects. Our study is the first to characterize the properties of FS-LAB and, by testing their efficacy on an in vivo rat model of thrombosis, demonstrate the potency of their antithrombotic effect. PMID:24936368
Abbaszadeh, S; Tavakoli, R; Sharifzadeh, A; Shokri, H
2015-12-01
The aim of this study was to assess the potential of lactic acid bacteria (LAB) such as Lactobacillus acidophilus, L. rhamnosus, L. casei, L. paracasei and Bifidobacterium bifidum to inhibit the outgrowth of some common food-spoiling fungi including Aspergillus niger, A. flavus, A. parasiticus and Penicillium chrysogenum. Bacterial isolates were cultured on Mann Rogosa Sharpe (MRS) broth and liquid cultures and supernatants were prepared. The antifungal activity was tested using the agar well diffusion method. Both liquid culture and supernatant of L. casei isolate exhibited high antifungal activity, followed by L. acidophilus and L. paracasei isolates. The least activity was recorded for the isolates B. bifidum, while the isolate L. rhamnosus was moderately active against tested fungi. The antifungal activity of the supernatants obtained from all probiotic isolates against fungi was significantly less than that of liquid cultures (P<0.05). Antifungal activity evaluation showed that A. flavus was the most inhibited fungus by probiotic bacteria, followed by P. chrysogenum, A. niger and A. parasiticus. These results suggest that probiotic bacteria strains have the ability to prevent the growth of pathogenic and mycotoxigenic fungi as antifungal agents for various biomedical applications. Copyright © 2015 Elsevier Masson SAS. All rights reserved.
Church, Deirdre L; Chow, Barbara L; Lloyd, Tracie; Gregson, Daniel B
2011-06-01
Automated repetitive PCR (rep-PCR; DiversiLab) was compared to PCR ribotyping of the 16S-23S RNA intergenic spacer of Clostridium difficile (CD) as the "gold standard" method for CD typing. PCR products were separated on DiversiLab LabChips (bioMérieux, St. Laurent, Quebec, Canada) utilizing a 2100 Bioanalyzer (Agilent Technologies, Santa Clara, CA) operating the DiversiLab v1.4 assay. Bioanalyzer data were exported to a secure DiversiLab website and analyzed with DiversiLab v3.4 software. Replicability of each method was verified by confirming that the 5 CD reference strains (RS) formed distinct clusters (CD4, CD6, VL0047, VL0013 [ribotype 027], VL0018 [ribotype 001]) by both typing methods. Ninety randomly selected clinical isolates (CS) were analyzed by both methods: 49 from community-acquired and 41 from hospital-acquired cases. A similarity index (SI) of ≥90% was used to define clusters when comparing the known RS cluster to the PCR ribotyping and rep-PCR patterns of CS. Fourteen different PCR-ribotype clusters were identified, but most CS formed 4 major clusters (i.e., CD4 [15/90; 17%], CD6 [17%], 027 [12%], and 001 [9%]). A total of 7 rep-PCR types were identified, but most CS formed 2 major rep-PCR clusters (i.e., CD4 [29/90; 32%] and CD6 [23%]); several PCR ribotypes occurred within a single rep-PCR cluster. Rep-PCR did not distinguish 027 or 001 isolates; i) 027 RS strain did not cluster, ii) eleven 027 CS strains clustered as CD4, iii) no 027 CS strains clustered with the 027 RS, and iv) only 2 001 CS clustered with the RS. Agreement between the PCR-ribotype and rep-PCR clusters only occurred for 35/90 (39%) of the CS using a rep-PCR SI of ≥90%. Rep-PCR time to results was similar, but the annual costs of routinely using this method are 32% higher than PCR ribotyping. Routine use of rep-PCR for CD typing is limited by its lack of definitive separation of the hypertoxigenic 027 or 001 outbreak CD strains. Copyright © 2011 Elsevier Inc. All rights
Pereira, Gilberto Vinícius de Melo; Miguel, Maria Gabriela da Cruz Pedrozo; Ramos, Cíntia Lacerda; Schwan, Rosane Freitas
2012-08-01
Spontaneous cocoa bean fermentations performed under bench- and pilot-scale conditions were studied using an integrated microbiological approach with culture-dependent and culture-independent techniques, as well as analyses of target metabolites from both cocoa pulp and cotyledons. Both fermentation ecosystems reached equilibrium through a two-phase process, starting with the simultaneous growth of the yeasts (with Saccharomyces cerevisiae as the dominant species) and lactic acid bacteria (LAB) (Lactobacillus fermentum and Lactobacillus plantarum were the dominant species), which were gradually replaced by the acetic acid bacteria (AAB) (Acetobacter tropicalis was the dominant species). In both processes, a sequence of substrate consumption (sucrose, glucose, fructose, and citric acid) and metabolite production kinetics (ethanol, lactic acid, and acetic acid) similar to that of previous, larger-scale fermentation experiments was observed. The technological potential of yeast, LAB, and AAB isolates was evaluated using a polyphasic study that included the measurement of stress-tolerant growth and fermentation kinetic parameters in cocoa pulp media. Overall, strains L. fermentum UFLA CHBE8.12 (citric acid fermenting, lactic acid producing, and tolerant to heat, acid, lactic acid, and ethanol), S. cerevisiae UFLA CHYC7.04 (ethanol producing and tolerant to acid, heat, and ethanol), and Acetobacter tropicalis UFLA CHBE16.01 (ethanol and lactic acid oxidizing, acetic acid producing, and tolerant to acid, heat, acetic acid, and ethanol) were selected to form a cocktail starter culture that should lead to better-controlled and more-reliable cocoa bean fermentation processes.
Pereira, Gilberto Vinícius de Melo; Miguel, Maria Gabriela da Cruz Pedrozo; Ramos, Cíntia Lacerda
2012-01-01
Spontaneous cocoa bean fermentations performed under bench- and pilot-scale conditions were studied using an integrated microbiological approach with culture-dependent and culture-independent techniques, as well as analyses of target metabolites from both cocoa pulp and cotyledons. Both fermentation ecosystems reached equilibrium through a two-phase process, starting with the simultaneous growth of the yeasts (with Saccharomyces cerevisiae as the dominant species) and lactic acid bacteria (LAB) (Lactobacillus fermentum and Lactobacillus plantarum were the dominant species), which were gradually replaced by the acetic acid bacteria (AAB) (Acetobacter tropicalis was the dominant species). In both processes, a sequence of substrate consumption (sucrose, glucose, fructose, and citric acid) and metabolite production kinetics (ethanol, lactic acid, and acetic acid) similar to that of previous, larger-scale fermentation experiments was observed. The technological potential of yeast, LAB, and AAB isolates was evaluated using a polyphasic study that included the measurement of stress-tolerant growth and fermentation kinetic parameters in cocoa pulp media. Overall, strains L. fermentum UFLA CHBE8.12 (citric acid fermenting, lactic acid producing, and tolerant to heat, acid, lactic acid, and ethanol), S. cerevisiae UFLA CHYC7.04 (ethanol producing and tolerant to acid, heat, and ethanol), and Acetobacter tropicalis UFLA CHBE16.01 (ethanol and lactic acid oxidizing, acetic acid producing, and tolerant to acid, heat, acetic acid, and ethanol) were selected to form a cocktail starter culture that should lead to better-controlled and more-reliable cocoa bean fermentation processes. PMID:22636007
Ranjbar, Reza; Behzadi, Payam; Najafi, Ali; Roudi, Raheleh
2017-01-01
A rapid, accurate, flexible and reliable diagnostic method may significantly decrease the costs of diagnosis and treatment. Designing an appropriate microarray chip reduces noises and probable biases in the final result. The aim of this study was to design and construct a DNA Microarray Chip for a rapid detection and identification of 10 important bacterial agents. In the present survey, 10 unique genomic regions relating to 10 pathogenic bacterial agents including Escherichia coli (E.coli), Shigella boydii, Sh.dysenteriae, Sh.flexneri, Sh.sonnei, Salmonella typhi, S.typhimurium, Brucella sp., Legionella pneumophila, and Vibrio cholera were selected for designing specific long oligo microarray probes. For this reason, the in-silico operations including utilization of the NCBI RefSeq database, Servers of PanSeq and Gview, AlleleID 7.7 and Oligo Analyzer 3.1 was done. On the other hand, the in-vitro part of the study comprised stages of robotic microarray chip probe spotting, bacterial DNAs extraction and DNA labeling, hybridization and microarray chip scanning. In wet lab section, different tools and apparatus such as Nexterion® Slide E, Qarray mini spotter, NimbleGen kit, TrayMix TM S4, and Innoscan 710 were used. A DNA microarray chip including 10 long oligo microarray probes was designed and constructed for detection and identification of 10 pathogenic bacteria. The DNA microarray chip was capable to identify all 10 bacterial agents tested simultaneously. The presence of a professional bioinformatician as a probe designer is needed to design appropriate multifunctional microarray probes to increase the accuracy of the outcomes.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Deveau, Aurelie; Labbe, Jessy
This chapter focuses on the Mycorrhiza Helper Bacteria (MHB), a generic name given to bacteria which stimulate the formation of mycorrhizal symbiosis. By extension, some bacterial strains that positively impact the functioning of mycorrhizal symbiosis are also called MHB. These bacteria have applicative interests, as they indirectly improve the health and growth of tree seedlings. MHB are not restricted to a specific type of ecosystem, but are rather generalist in the way that they associate with both herbaceous and woody mycorrhizal plants from boreal, temperate, arid and tropical ecosystems. However, understanding the molecular mechanisms and their specificities will help usmore » to know more about the ecology of the MHB. The process of acquisition varies between fungal species; while ectomycorrhizal fungi most probably recurrently acquire them from the environment, the association between bacterial endosymbionts and Glomeromycota probably dates back to very ancient times, and has since been vertically transmitted.« less
Use of thermophilic bacteria for bioremediation of petroleum contaminants
DOE Office of Scientific and Technical Information (OSTI.GOV)
Al-Maghrabi, I.M.A.; Bin Aqil, A.O.; Chaalal, O.
1999-01-01
Several strains of thermophilic bacteria were isolated from the environment of the United Arab Emirates. These bacteria show extraordinary resistance to heat and have their maximum growth rate around 60--80 C. This article investigates the potential of using these facultative bacteria for both in situ and ex situ bioremediation of petroleum contaminants. In a series of batch experiments, bacterial growth was observed using a computer image analyzer following a recently developed technique. These experiments showed clearly that the growth rate is enhanced in the presence of crude oil. This is coupled with a rapid degradation of the crude oil. Thesemore » bacteria were found to be ideal for breaking down long-chain organic molecules at a temperature of 40 C, which is the typical ambient temperature of the Persian Gulf region. The same strains of bacteria are also capable of surviving in the presence of the saline environment that can prevail in both sea water and reservoir connate water. This observation prompted further investigation into the applicability of the bacteria in microbial enhanced oil recovery. In the United Arab Emirates, the reservoirs are typically at a temperature of around 85 C. Finally, the performance of the bacteria is tested in a newly developed bioreactor that uses continuous aeration through a transverse slotted pipe. This reactor also uses mixing without damaging the filamentous bacteria. In this process, the mechanisms of bioremediation are identified.« less
[Occurrence of bacteria of the Yersinia genus in surface water].
Krogulska, B; Maleszewska, J
1992-01-01
The aim of the study was determination of the frequency of occurrence of Yersinia genus bacteria in surface waters polluted to various degrees with bacteria of the coliform and of fecal coli. For detection of Yersinia rods the previously elaborated medium Endo MLCe and the membrane filter method were applied. Samples of 42 surface waters were examined, including 26 from rivers and 16 from lakes, ponds and clay-pits. On the basis of sanitary bacteriological analysis 16 surface waters were classified to class I purity, 10 to class II, the remaining ones to class III or beyond classification. Yersinia rods were detected in 15 water bodies that is 35.7% of the examined waters. A total of 27 Yersinia strains were identified with dominance of Y. intermedia (14 strains) and Y. enterocolitica (10 strains). Three strains represented by the species Yersinia frederiksenii. Most of the Y. enterocolitica strains belonged to biotype 1, the particular strains being represented by various serotypes. Hence their different origin may be concluded. The pathogenic serotypes 0:3 and 0:9 of Yersinia enterocolitica were not detected.
Colonization by aerobic bacteria in karst: Laboratory and in situ experiments
Personne, J.-C.; Poty, F.; Mahler, B.J.; Drogue, C.
2004-01-01
Experiments were carried out to investigate the potential for bacterial colonization of different substrates in karst aquifers and the nature of the colonizing bacteria. Laboratory batch experiments were performed using limestone and PVC as substrates, a natural bacterial isolate and a known laboratory strain (Escherichia coli [E. coli]) as inocula, and karst ground water and a synthetic formula as growth media. In parallel, fragments of limestone and granite were submerged in boreholes penetrating two karst aquifers for more than one year; the boreholes are periodically contaminated by enteric bacteria from waste water. Once a month, rock samples were removed and the colonizing bacteria quantified and identified. The batch experiments demonstrated that the natural isolate and E. coli both readily colonized limestone surfaces using karst ground water as the growth medium. In contrast, bacterial colonization of both the limestone and granite substrates, when submerged in the karst, was less intense. More than 300 bacterial strains were isolated over the period sampled, but no temporal pattern in colonization was seen as far as strain, and colonization by E. coli was notably absent, although strains of Salmonella and Citrobacter were each observed once. Samples suspended in boreholes penetrating highly fractured zones were less densely colonized than those in the borehole penetrating a less fractured zone. The results suggest that contamination of karst aquifers by enteric bacteria is unlikely to be persistent. We hypothesize that this may be a result of the high flow velocities found in karst conduits, and of predation of colonizing bacteria by autochthonous zooplankton.
Digestion of rice straw and oil palm fronds by microflora from rumen and termite bacteria, in vitro.
Ramin, M; Alimon, A R; Panandam, J M; Sijam, K; Javanmard, A; Abdullah, N
2008-02-15
The digestion and Volatile Fatty Acid (VFA) production from rice straw and oil palm fronds by cellulolytic bacteria isolated from the termite Coptotermes curvignathus were investigated. The bacteria were Acinetobacter strain Raminalimon, Enterobacter aerogenes strain Razmin C, Enterobacter cloacae strain Razmin B, Bacillus cereus strain Razmin A and Chryseobacterium kwangyangense strain Cb. Acinetobacter strain Raminalimon is an aerobic bacterium, while the other species are facultative anaerobes. There were significant differences (p<0.05) among the bacteria for Dry Matter (DM) lost and acetic acid production from rice straw and Acinetobacter strain Raminalimon showed the highest activity. The facultative bacteria C. kwangyangense strain Cb (cfu mL(-1) 231 x 10(-6), OD: 0.5), E. cloacae (cfu mL(-1) 68 x 10(-7), OD: 0.5) and E. aerogenes (cfu mL(-1) 33 x 10(-7), OD: 0.5) were used for digestion study with the rumen fluid microflora. The in vitro gas production technique was applied for the comparative study and the parameters measured were pH, gas (volume), dry matter lost, acetic acid, propionic acid and butyric acid concentrations. pH was not significantly (p<0.05) different among the five treatments. The bacterium C. kwangyangense strain Cb showed the highest activity (p<0.05) for DM lost, acetic acid, propionic acid and butyric acid production from rice straw when compared to the other bacterial activities. There was no significance (p<0.05) difference between the three bacteria for the dry matter lost of oil palm fronds but the production of Volatile Fatty Acids (VFA) was significantly (p<0.05) high in the treatment which was inoculated with C. kwangyangense strain Cb. The Gen Bank NCBI/EMBL accession numbers for the bacterial strains are EU332791, EU305608, EU305609, EU294508 and EU169201.