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Sample records for interrogans serovar lai

  1. Identification and partial characterization of a novel hemolysin from Leptospira interrogans serovar lai.

    PubMed

    Lee, S H; Kim, K A; Park, Y G; Seong, I W; Kim, M J; Lee, Y J

    2000-08-22

    It has been suggested that leptospiral hemolysins are important in the virulence and pathogenesis of leptospirosis. We have isolated an Escherichia coli clone carrying the 7.8kb DNA insert from a genomic library of Leptospira interrogans serovar lai by plaque hybridization using a sequence derived from the sphingomyelinase C gene (sphA) of L. borgpetersenii. The clone showed a clear beta-hemolytic zone on sheep blood agar and high hemolytic activities on both human and sheep erythrocytes in liquid assays. The clone carried at least two genes responsible for the hemolytic activities, encoded by two open reading frames of 1662 and 816 nucleotides, which are named sphH and hap-1 (hemolysis associated protein-1), respectively. The SphH showed 75% homology to the SphA at the amino acid level, and the Hap-1 showed no significant homology in major databases. Interestingly, however, E. coli cells harboring sphH did not show sphingomyelinase or phospholipase activities. Moreover, SphH-mediated hemolysis was osmotically protected by polyethylene glycol 5000, suggesting that the hemolysis is likely to be caused by pore formation on the membrane. The SphH was successfully expressed in E. coli as a histidine (His)-SphH fusion protein. Both sphH and hap-1 were highly conserved among the Leptospira species, except for the absence of sphH in non-pathogenic L. biflexa serovar patoc. We concluded that the SphH is a novel hemolysin of a pathogenic Leptospira species, which may be a putative pore-forming protein.

  2. [Construction of genomic library of L. interrogans serovar lai using lambda gt11 as the vector and a study of recombiant plasmid pDL121].

    PubMed

    Liu, H; Dai, B; Jing, B; Wu, W; Li, S; Fang, Z; Zhao, H; Ye, D; Yan, R; Liu, J; Song, S; Yang, Y; Zhang, Y; Liu, F; Tu, Y; Yang, H; Huang, Z; Liang, L; Hu, L; Zhao, M

    1997-03-01

    A genomic library of L. interrogans serovar lai strain 017 has been constructed using lambda gt11 as the vector. DNA was partially digested by two blunt-end restriction enzymes, then methylated with EcoR I methylase; after EcoR I linker was added to the DNA, the linker-ended DNA was ligated to the dephosphorylated EcoR I digested lambda gt11 arms. The recombined DNA was packaged in vitro, and used to transduct E. coli Y1090 for amplification. There were 2.1 x 10(6) recombinant bacteriophages as recognized by their ability to form white plaques plated on Lac host in the presence of both IPTG and X-Ga1. A positive clone, designated lambda DL12, was screened with a rabbit anti-serum against L. interrogans serovar lai from the genomic library. The DNA from lambda DL12 was subcloned into plasmid pUC18. A recombinant (designated as pDL121) was obtained. SDS-PAGE analysis indicated that a 23 kd was expressed in E. coli JM 103 harboring pDL121. Western blotting analysis showed that a specific protein band molecular weight of 23 kd could be recognized by the rabbit antiserum against L. interrogans serovar lai strain 017.

  3. [Nucleotide sequence analysis of a species specific probe by an inserted fragment from recombinant plasmid pCX7 of L. interrogans sensu stricto serovar lai].

    PubMed

    Dai, B; Xiao, J; Yan, Z; Shen, C; Li, S; Fang, Z

    1998-12-01

    The etiological agents of leptospirosis are the pathogenic leptospires (L. interrogans sensu lato) which can be divided into 223 serovars organized into 23 serogroups. The serovar remains the basic taxon, but serotyping may now be accomplished and recognized by acceptable methods. Complementary molecular approaches are being used extensively to assess genetic relatedness amongst leptospires with restriction endonuclese analysis (REA), pulse field gel electrophoresis (PFGE) and DNA-DNA hybridization as well established tools. However, the method is cumbersome and unsuitable for routine application. To develop a sensitive and specific method for identification of pathogenic leptospires, a genomic library of L. interrogans sensu stricto serovar lai was constructed with the plasmid vector pUC9. A recombinant plasmid, designated pCX7 which has homologous fragment of pathogenic leptospires was screened from the bank. pCX7 could recognize pathogenic leptospiral DNA fragment 1.7 kb of strain 017 without cross hybridization to nonpathogenic leptospiral DNA. Inserted fragment of pCX7 DNA sequencing was performed by Dr. Yan Zhengxin (Max-Plank-Institut fur Biology, Tubingen, Germany). Insert fragment was cloned into pBluescript and sequenced by using ABI(Applied Bio. Systems, Model 373A). Nucleotide sequences were analyzed by Dr. Xiao Jianguo (Texas University Medical School and School of Public Health, Center for Infectious Diseases) using a suit of computer program (NIH). One open reading frame of 306 nucleotids were identified. There were identifiable initiation codons, terminators, pribnow box and sextama box within the sequenced regions. These results further confirmed that the little homology between L. interrogans sensu strito and L. borgpeterseni serovar javanica, L. inadai serovar ranarun and serovar manhao (L. genomospecies 2), L. biflexa serovar patoc, L. illini. pCX7 DNA probe could provide a base for identification and classification of leptospires.

  4. Cloning of a hemolysin gene from Leptospira interrogans serovar hardjo.

    PubMed Central

    del Real, G; Segers, R P; van der Zeijst, B A; Gaastra, W

    1989-01-01

    A DNA fragment encoding both hemolysin and sphingomyelinase C activity was cloned from the pathogenic bacterium Leptospira interrogans serovar hardjo. Initial clones were obtained by screening a genomic library in EMBL3 for hemolytic activity. Both hemolytic and sphingomyelinase C activities were coded for by a 3.9-kilobase BamHI fragment. The hemolysin was expressed from its own promoter in Escherichia coli K-12. Similar DNA sequences were also present in the serovars tarassovi and ballum. Images PMID:2744864

  5. Copurification of Leptospira interrogans serovar pomona hemolysin and sphingomyelinase C.

    PubMed Central

    Bernheimer, A W; Bey, R F

    1986-01-01

    The hemolytic and sphingomyelinase C activities of supernatants of cultures of Leptospira interrogans serovar pomona tended to copurify when isoelectric fractionation was carried out. Both activities focused primarily at pH 8.1. Considered in conjunction with other circumstantial evidence, the results led to the conclusion that sphingomyelinase C is responsible for hemolysis. PMID:3019890

  6. Complete genome sequence of Leptospira interrogans serovar Bratislava, strain PigK151

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genus Leptospira contains pathogens serologically classified into over 250 serovars, intermediate pathogens and saprophytes with genetic classification into 21 different species. Worldwide, leptospirosis is one of the most widespread zoonoses. L. interrogans serovar Bratislava has been isolated ...

  7. Whole Genome Sequencing Allows Better Understanding of the Evolutionary History of Leptospira interrogans Serovar Hardjo

    PubMed Central

    Llanes, Alejandro; Restrepo, Carlos Mario; Rajeev, Sreekumari

    2016-01-01

    The genome of a laboratory-adapted strain of Leptospira interrogans serovar Hardjo was sequenced and analyzed. Comparison of the sequenced genome with that recently published for a field isolate of the same serovar revealed relatively high sequence conservation at the nucleotide level, despite the different biological background of both samples. Conversely, comparison of both serovar Hardjo genomes with those of L. borgpetersenii serovar Hardjo showed extensive differences between the corresponding chromosomes, except for the region occupied by their rfb loci. Additionally, comparison of the serovar Hardjo genomes with those of different L. interrogans serovars allowed us to detect several genomic features that may confer an adaptive advantage to L. interrogans serovar Hardjo, including a possible integrated plasmid and an additional copy of a cluster encoding a membrane transport system known to be involved in drug resistance. A phylogenomic strategy was used to better understand the evolutionary position of the Hardjo serovar among L. interrogans serovars and other Leptospira species. The proposed phylogeny supports the hypothesis that the presence of similar rfb loci in two different species may be the result of a lateral gene transfer event. PMID:27442015

  8. Cytotoxic activity and probable apoptotic effect of Sph2, a sphigomyelinase hemolysin from Leptospira interrogans strain Lai.

    PubMed

    Zhang, Yi-Xuan; Geng, Yan; Yang, Jun-Wei; Guo, Xiao-Kui; Zhao, Guo-Ping

    2008-02-29

    Our previous work confirmed that Sph2/LA1029 was a sphigomyelinase-like hemolyisn of Leptospira interrogans serogroup Icterohaemorrhagiae serovar Lai. Characteristics of both hemolytic and cytotoxic activities of Sph2 were reported in this paper. Sph2 was a heat-labile neutral hemolysin and had similar hemolytic behavior as the typical sphingomyelinase C of Staphylococcus aureus upon sheep erythrocytes. The cytotoxic activity of Sph2 was shown in mammalian cells such as BALB/C mouse lymphocytes and macrophages, as well as human L-02 liver cells. Transmission electron microscopic observation showed that the Sph2 treated BALB/C mouse lymphocytes were swollen and ruptured with membrane breakage. They also demonstrated condensed chromatin as a high-density area. Cytoskeleton changes were observed via fluorescence confocal microscope in Sph2 treated BALB/C mouse lymphocytes and macrophages, where both cytokine IL-1beta and IL-6 were induced. In addition, typical apoptotic morphological features were observed in Sph2 treated L-02 cells via transmission electron microscope and the percentage of apoptotic cells did increase after the Sph2 treatment detected by flow cytometry. Therefore, Sph2 was likely an apoptosis-inducing factor of human L-02 liver cells.

  9. First Genome Sequence of Leptospira interrogans Serovar Pomona, Isolated from a Bovine Abortion

    PubMed Central

    Varni, Vanina; Koval, Ariel; Nagel, Ariel; Ruybal, Paula

    2016-01-01

    Leptospirosis is a widespread zoonosis and a re-emergent disease of global distribution with major relevance in veterinary production. Here, we report the whole-genome sequence of Leptospira interrogans serovar Pomona strain AKRFB, isolated from a bovine abortion during a leptospirosis outbreak in Argentina. PMID:27198013

  10. First Genome Sequence of Leptospira interrogans Serovar Pomona, Isolated from a Bovine Abortion.

    PubMed

    Varni, Vanina; Koval, Ariel; Nagel, Ariel; Ruybal, Paula; Caimi, Karina; Amadio, Ariel F

    2016-05-19

    Leptospirosis is a widespread zoonosis and a re-emergent disease of global distribution with major relevance in veterinary production. Here, we report the whole-genome sequence of Leptospira interrogans serovar Pomona strain AKRFB, isolated from a bovine abortion during a leptospirosis outbreak in Argentina.

  11. Transmission of Leptospira interrogans serovar Balcanica infection among socially housed brushtail possums in New Zealand.

    PubMed

    Day, T D; O'Connor, C E; Waas, J R; Pearson, A J; Matthews, L R

    1998-07-01

    Leptospira interrogans serovar balcanica is a potential vector being investigated for spreading a biological control agent among introduced brushtail possums (Trichosurus vulpecula) in New Zealand. As previous studies have shown that possums are unlikely to contract leptospirosis through a contaminated environment alone, the objective was to determine whether L. interrogans serovar balcanica could be transmitted between sexually mature, socially housed possums. Possums were infected experimentally with L. interrogans serovar balcanica and housed in pairs or groups with uninfected possums for either 70 or 140 days, during the breeding or non-breeding seasons. No transmission occurred between any infected and uninfected possums during the non-breeding season. However, transmission occurred between females that had been socially housed in pairs or groups in the breeding season. Mixed sex transmission also occurred in pairs and groups, both from males to females and from females to males. Mixed sex transmission usually occurred rapidly (< 44 days) and was not associated with the production of offspring. No transmission occurred between males during the breeding or the non-breeding seasons. Transmission probably occurs as a result of affiliative or sexual behaviour, but is unlikely to occur through fighting. The social transmission pathways determined in this study suggest that L. interrogans serovar balcanica may have the transmission attributes desired in a vector for biological control.

  12. Leptospira interrogans serovar hardjo in the kidneys and genital tracts of naturally infected sheep.

    PubMed

    Cerri, D; Nuvoloni, R; Ebani, V; Pedrini, A; Mani, P; Andreani, E; Farina, R

    1996-04-01

    A bacteriological study was carried out to identify possible renal and/or genital carriers of Leptospira interrogans serovar hardjo. L. hardjo was found at slaughter in the kidneys of three seropositive ewes, but not in uterus or salpinges of these animals.

  13. Leptospira interrogans serovar copenhageni harbors two lexA genes involved in SOS response.

    PubMed

    Fonseca, Luciane S; da Silva, Josefa B; Milanez, Juliana S; Monteiro-Vitorello, Claudia B; Momo, Leonardo; de Morais, Zenaide M; Vasconcellos, Silvio A; Marques, Marilis V; Ho, Paulo L; da Costa, Renata M A

    2013-01-01

    Bacteria activate a regulatory network in response to the challenges imposed by DNA damage to genetic material, known as the SOS response. This system is regulated by the RecA recombinase and by the transcriptional repressor lexA. Leptospira interrogans is a pathogen capable of surviving in the environment for weeks, being exposed to a great variety of stress agents and yet retaining its ability to infect the host. This study aims to investigate the behavior of L. interrogans serovar Copenhageni after the stress induced by DNA damage. We show that L. interrogans serovar Copenhageni genome contains two genes encoding putative LexA proteins (lexA1 and lexA2) one of them being potentially acquired by lateral gene transfer. Both genes are induced after DNA damage, but the steady state levels of both LexA proteins drop, probably due to auto-proteolytic activity triggered in this condition. In addition, seven other genes were up-regulated following UV-C irradiation, recA, recN, dinP, and four genes encoding hypothetical proteins. This set of genes is potentially regulated by LexA1, as it showed binding to their promoter regions. All these regions contain degenerated sequences in relation to the previously described SOS box, TTTGN 5CAAA. On the other hand, LexA2 was able to bind to the palindrome TTGTAN10TACAA, found in its own promoter region, but not in the others. Therefore, the L. interrogans serovar Copenhageni SOS regulon may be even more complex, as a result of LexA1 and LexA2 binding to divergent motifs. New possibilities for DNA damage response in Leptospira are expected, with potential influence in other biological responses such as virulence.

  14. Molecular characterization, serotyping, and antibiotic susceptibility profile of Leptospira interrogans serovar Copenhageni isolates from Brazil.

    PubMed

    Miraglia, Fabiana; Matsuo, Minekazo; Morais, Zenaide Maria; Dellagostin, Odir Antonio; Seixas, Fabiana Kömmling; Freitas, Julio César; Hartskeerl, Rudy; Moreno, Luisa Zanolli; Costa, Bárbara Letícia; Souza, Gisele Oliveira; Vasconcellos, Silvio Arruda; Moreno, Andrea Micke

    2013-11-01

    Leptospira interrogans serogroup Icterohaemorrhagiae is the major serogroup infecting humans worldwide, and rodents and dogs are the most significant transmission sources in urban environments. Knowledge of the prevalent serovars and their maintenance hosts is essential to understand the epidemiology of leptospirosis. In this study, 20 Leptospira isolates were evaluated by pulsed-field gel electrophoresis (PFGE), variable number tandem-repeat analysis (VNTR), serotyping, and determination of antimicrobial resistance profile. Isolates, originated from bovine, canine, human, and rodent sources, were characterized by microscopic agglutination test with polyclonal and monoclonal antibodies and were identified as L. interrogans serogroup Icterohaemorrhagiae serovar Copenhageni. MICs of antimicrobials often used in veterinary medicine were determined by broth microdilution test. Most of tested antibiotics were effective against isolates, including penicillin, ampicillin, and ceftiofur. Higher MIC variability was observed for fluoroquinolones and neomycin; all isolates were resistant to trimethoprim/sulfamethoxazole and sulphadimethoxine. Isolates were genotyped by PFGE and VNTR; both techniques were unable to discriminate between serovars Copenhageni and Icterohaemorrhagiae, as expected. PFGE clustered all isolates in 1 pulsotype, indicating that these serovars can be transmitted between species and that bovine, rodent, and dogs can maintain them in the environment endangering the human population.

  15. Effects of intrauterine challenge with Leptospira interrogans serovar hardjo on fertility in cattle.

    PubMed

    Vahdat, F; Bey, R F; Williamson, N B; Whitmore, H L; Zemjanis, R; Robinson, R A

    1983-11-01

    The purpose of this study was to determine the effects of Leptospira interrogans serovar hardio on fertility in cattle. Twenty seronegative mature dairy cows were assigned to two groups. Group I (challenged cows) was bred by a seronegative bull followed by intrauterine infusion (within 30 minutes) of Leptospira interrogans serovar hardjo. Group II was bred by the same bull followed by intrauterine infusion of 5 ml of sterile culture medium. Blood samples were collected at two-day intervals to monitor serum antibody titers. Daily blood cultures for 10 days and weekly urine cultures for five weeks were performed to monitor the animals for leptospiremia and leptospiuria. Cows were slaughtered 35 days post-breeding, and their reproductive tracts were examined. All animals remained clinically normal following intrauterine challenge. There was no difference in pregnancy rates (Group I, 7/10; Group II, 6/10). All embryos, reproductive tracts, and kidneys appeared normal. A microscopic agglutination test (MA) showed that 4 of 10 challenged cows developed serum antibody titers between 8 and 20 days after challenge. However, on the basis of the hamster passive protection test, all challenged cows had serum antibodies present. All blood and urine cultures were negative through the experimental period, as were the final kidney and uterine cultures. In a second experiment, six seronegative cows were infused with killed microorganisms immediately after insemination. Results of a microscopic agglutination test and a hamster passive protection test indicated that these cows did not develop humoral antibodies against serovar hardjo. These results indicated that intrauterine inoculation of Leptospira interrogans serovar hardjo (hamster-adapted strain) following breeding did not affect pregnancy rates despite an intrauterine challenge which caused the development of humoral antibodies.

  16. Geographical dissemination of Leptospira interrogans serovar Pomona during seasonal migration of California sea lions.

    PubMed

    Zuerner, Richard L; Cameron, Caroline E; Raverty, Stephen; Robinson, John; Colegrove, Kathleen M; Norman, Stephanie A; Lambourn, Dyanna; Jeffries, Steven; Alt, David P; Gulland, Frances

    2009-05-28

    Leptospirosis is one of the most widespread bacterial zoonoses in the world and affects most mammalian species. Although leptospirosis is well documented and characterized in terrestrial species, less information is available regarding the distribution and impact of leptospirosis in marine mammals. Additionally, the role of animal migrations on the geographical spread of leptospirosis has not been reported. Periodic epizootic outbreaks of acute leptospirosis among California sea lions (Zalophus californianus) have been reported since 1971. In this study, we collected samples from California sea lions stranded along the Pacific coast of North America during the most recent epidemic in 2004, and maintained leptospirosis surveillance of the California sea lion population along the California coast through 2007. Several isolates of Leptospira interrogans serovar Pomona were obtained from kidney and urine samples collected during this study, a finding consistent with serological evidence that California sea lions are persistently exposed to this leptospiral serovar. Combined, these data support a model whereby California sea lions are maintenance hosts for L. interrogans serovar Pomona, yet periodically undergo outbreaks of acute infection. During the 2004 outbreak, the incidence of new leptospirosis cases among California sea lions coincided with the seasonal movement of male sea lions from rookeries along the coast of central and southern California north as far as British Columbia. These data show that seasonal animal movement contributes to the distribution of leptospirosis across a large geographical region.

  17. [The serovars of Leptospira interrogans isolated from cases of human leptospirosis in São Paulo, Brazil].

    PubMed

    Sakata, E E; Yasuda, P H; Romero, E C; Silva, M V; Lomar, A V

    1992-01-01

    Eighteen strains of L. interrogans isolated from human cases were serotyped by the agglutinin-absorption test at Instituto Adolfo Lutz in São Paulo, Brazil. Fourteen were identified as serovar copenhageni (icterohaemorrhagiae serogroup), 2 as canicola (canicola serogroup), 1 as castellonis (Ballum serogroup) and 1 as pomona serogroup (serovar not yet defined). The frequency of serovar copenhageni in 100% of the isolates in icterohaemorrhagiae serogroup is emphasized and more studies to verify the real serovars prevalence as subsidy to the epidemiology of this infection are suggested by the authors.

  18. Restriction endonuclease DNA analysis of Leptospira interrogans serovars icterohaemorrhagiae and hebdomadis.

    PubMed Central

    Marshall, R B; Winter, P J; Yanagawa, R

    1984-01-01

    Antigenic variants of Leptospira interrogans serovars copenhageni and hebdomadis were examined by bacterial restriction endonuclease DNA analysis with EcoRI, XhoI, SalI, BstEII, and HindIII as the digesting enzymes. The antigenic variants were stable cloned strains which had been cultivated in media containing homologous immune serum. One of the strains examined has been reported elsewhere (R. Yanagawa and J. Takashima, Infect. Immun. 10:1439-1442) as having an antigenic makeup which more closely resembles serovar kremastos than the serovar hebdomadis parent. The closely antigenically related but naturally occurring serovars icterhaemorrhagiae strain RGA and copenhageni strain M20 were examined in parallel. No differences could be shown between the hebdomadis parent and any of its mutants. Serovars copenhageni and icterohaemorrhagiae produced patterns which differed in the high-molecular-weight bands only. The Shibaura parent strain did not differ from copenhageni M20, but the Shibaura M1 strain differed from the other mutants and from icterohaemorrhagiae RGA in its high-molecular-weight bands. Images PMID:6092434

  19. Experimental infection of calves and sheep with Leptospira interrogans serovar balcanica.

    PubMed

    Durfee, P T; Presidente, P J

    1979-10-01

    Two of four calves inoculated with Leptospira interrogans serovar balcanica developed low microscopic agglutinating (MA) titres to serovar hardjo. A third calf had an MA titre of 1:1024 by day 19 post-inoculation (PI). Transient leptospiruria was recorded in one calf on days 12 and 13 PI. An in-contact calf did not seroconvert. None of the calves had fever or other clinical signs of disease. Four ewes inoculated with balcanica developed MA titres to hardjo by day 13 PI, and a transient leptospiruria between days 14 and 25 PI. None of the ewes showed any evidence of clinical disease and three of them delivered healthy lambs 22 to 64 days PI. One ewe had mild lesions of focal interstitial nephritis.

  20. Variable Nucleotide Tandem-Repeat Analysis Revealing a Unique Group of Leptospira interrogans Serovar Pomona Isolates Associated with California Sea Lions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leptospira interrogans serovar Pomona is commonly isolated from a variety of wildlife and domesticated livestock. It is difficult to assess whether disease outbreaks with serovar Pomona in given animal populations are due to endemic infections or accidental exposure. Unlike many leptospiral serovars...

  1. Production and characterization of monoclonal antibodies specific for Leptospira borgpetersenii serovar hardjo type hardjobovis and Leptospira interrogans serovar hardjo type hardjoprajitno.

    PubMed Central

    Surujballi, O; Howlett, C; Henning, D

    1999-01-01

    Murine monoclonal antibodies were produced by immunizing BALB/c mice with a killed whole-cell antigen prepared from Leptospira borgpetersenii serovar hardjo type hardjobovis. Six of these antibodies recognized epitopes on the homologous antigen and on whole-cell antigen prepared from Leptospira interrogans serovar hardjo type hardjoprajitno. These antibodies did not cross-react with whole-cell antigens prepared from L. borgpetersenii serovar sejroe, 10 other pathogenic Leptospira serovars, or the saprophytic Leptospira biflexa serovar patoc. Three other monoclonal antibodies reacted with antigens prepared from the 2 hardjo serovars and serovar sejroe but not with antigens from the 10 other pathogenic serovars, or serovar patoc. The epitopes recognized by all of the hardjo-specific antibodies and 2 of the 3 hardjo/sejroe-specific antibodies were susceptible to sodium meta-periodate oxidation. All of the antibodies were characterized by Western blots with the hardjobovis whole-cell antigen. Each of the 9 monoclonal antibodies was inhibited from binding to the hardjobovis antigen by bovine sera which were obtained from cattle experimentally infected with hardjobovis and from field cattle, with anti-serovar hardjo microscopic agglutination test antibody titres ranging from 100 to 12800. Some of these antibodies may be suitable for incorporation into competitive enzyme immunoassays for the specific detection of antibodies to either of the hardjo serovars. Images Figure 1. PMID:9918336

  2. Leptospira interrogans serovar hardjo vaccination of pregnant beef cows and subsequent growth rate of progeny.

    PubMed

    Holroyd, R G

    1980-10-01

    Five experiments with Leptospira interrogans serovar hardjo vaccine were carried out over a 6-year period in pregnant Brahman-cross and Sahiwal-cross cows in the dry tropics on northern Queensland. The numbers ranged from 127 breeders aged 2 to 5 years in 1972 to 344 breeders aged 2 to 9 years in 1977. Half of the cows were vaccinated twice in mid-pregnancy except for 1977, when they were vaccinated once. In 1975-1977 inclusive, half of the heifers were given an additional dose of vaccine at commencement of mating. Vaccination caused a significant (P less than 0.01) reduction of prenatal loss but not of perinatal or postnatal losses. Growth rates of calves from vaccinated and unvaccinated dams were similar.

  3. Asymptomatic and chronic carriage of Leptospira interrogans serovar Pomona in California sea lions (Zalophus californianus).

    PubMed

    Prager, K C; Greig, Denise J; Alt, David P; Galloway, Renee L; Hornsby, Richard L; Palmer, Lauren J; Soper, Jennifer; Wu, Qingzhong; Zuerner, Richard L; Gulland, Frances M D; Lloyd-Smith, James O

    2013-05-31

    Since 1970, periodic outbreaks of leptospirosis, caused by pathogenic spirochetes in the genus Leptospira, have caused morbidity and mortality of California sea lions (Zalophus californianus) along the Pacific coast of North America. Yearly seasonal epizootics of varying magnitude occur between the months of July and December, with major epizootics occurring every 3-5 years. Genetic and serological data suggest that Leptospira interrogans serovar Pomona is the infecting serovar and is enzootic in the California sea lion population, although the mechanism of persistence is unknown. We report asymptomatic carriage of Leptospira in 39% (33/85) of wild, free-ranging sea lions sampled during the epizootic season, and asymptomatic seroconversion with chronic asymptomatic carriage in a rehabilitated sea lion. This is the first report of asymptomatic carriage in wild, free-ranging California sea lions and the first example of seroconversion and asymptomatic chronic carriage in a sea lion. Detection of asymptomatic chronic carriage of Leptospira in California sea lions, a species known to suffer significant disease and mortality from the same Leptospira strain, goes against widely-held notions regarding leptospirosis in accidental versus maintenance host species. Further, chronic carriage could provide a mechanism for persistent circulation of Leptospira in the California sea lion population, particularly if these animals shed infectious leptospires for months to years.

  4. Three case studies involving Leptospira interrogans serovar pomona infection in mixed farming units.

    PubMed

    Gummow, B; Myburgh, J G; Thompson, P N; van der Lugt, J J; Spencer, B T

    1999-03-01

    Three case studies involving Leptospira interrogans serovar pomona outbreaks within mixed farming systems in South Africa are described. On 2 farms, pigs constituted the main enterprise with cattle and sheep of secondary importance. On each of these 2 farms, abortion due to L. pomona in sows was confirmed by culture, and antibody titres to pomona were detected in cattle, sheep, horses and dogs. On the 3rd farm, a piggery was of secondary importance to cattle farming. Abortion and death in cows occurred on this farm and serology showed titres to various serovars, including pomona. L. pomona was also isolated from bovine urine, an aborted bovine foetus and kidneys from slaughtered pigs. This particular case study was regarded as clinically atypical in that adult Jersey cattle died of acute leptospirosis in a semiarid region of South Africa. In all 3 case studies, the poor management of pig effluent and of the drinking water and its sources played a pivotal role in the transmission of the disease. Inadequate vaccination of animals against Leptospira and poor record-keeping within the secondary farming enterprises were also contributing factors to the spread of leptospirosis.

  5. Sheep as maintenance host for Leptospira interrogans serovar hardjo subtype hardjobovis.

    PubMed

    Gerritsen, M J; Koopmans, M J; Peterse, D; Olyhoek, T

    1994-09-01

    Transmission of Leptospira interrogans serovar hardjo subtype hardjobovis from naturally infected sheep to uninfected sheep and calves was studied. A microscopic agglutination test and ELISA were used to determine specific antibody responses in serum. Polymerase chain reaction was used to detect bacterial shedding in urine. Six sheep were derived from a dairy farm where cows were infected with L hardjobovis. Three of these sheep were seropositive for L hardjobovis, and 1 also shed leptospires in the urine. The other 2 sheep shed leptospires in the urine 7 days after the first observation date. The 6 sheep were placed on an isolated pasture together with a second group of 6 noninfected sheep. During the observation period of 140 days, 1 sheep of the second group became infected with L hardjobovis. On 5 consecutive days, a urine mixture from the 4 infected sheep was sprayed on the heads of 4 noninfected calves. Within 56 days, all calves that had been sprayed with urine shed L hardjobovis in the urine and became seropositive for L hardjobovis.

  6. Whole-Genome Sequence of Leptospira interrogans Serovar Hardjo Subtype Hardjoprajitno Strain Norma, Isolated from Cattle in a Leptospirosis Outbreak in Brazil.

    PubMed

    Cosate, M R V; Soares, S C; Mendes, T A; Raittz, R T; Moreira, E C; Leite, R; Fernandes, G R; Haddad, J P A; Ortega, J Miguel

    2015-11-05

    Leptospirosis is caused by pathogenic bacteria of the genus Leptospira spp. This neglected re-emergent disease has global distribution and relevance in veterinary production. Here, we report the whole-genome sequence and annotation of Leptospira interrogans serovar Hardjo subtype Hardjoprajitno strain Norma, isolated from cattle in a livestock leptospirosis outbreak in Brazil.

  7. Whole-Genome Sequence of Leptospira interrogans Serovar Hardjo Subtype Hardjoprajitno Strain Norma, Isolated from Cattle in a Leptospirosis Outbreak in Brazil

    PubMed Central

    Soares, S. C.; Mendes, T. A.; Raittz, R. T.; Moreira, E. C.; Leite, R.; Fernandes, G. R.; Haddad, J. P. A.; Ortega, J. Miguel

    2015-01-01

    Leptospirosis is caused by pathogenic bacteria of the genus Leptospira spp. This neglected re-emergent disease has global distribution and relevance in veterinary production. Here, we report the whole-genome sequence and annotation of Leptospira interrogans serovar Hardjo subtype Hardjoprajitno strain Norma, isolated from cattle in a livestock leptospirosis outbreak in Brazil. PMID:26543126

  8. Management practices as risk factors for the presence of bulk milk antibodies to Salmonella, Neospora caninum and Leptospira interrogans serovar hardjo in Irish dairy herds.

    PubMed

    O' Doherty, E; Berry, D P; O' Grady, L; Sayers, R

    2014-06-01

    A survey of management practices in 309 Irish dairy herds was used to identify risk factors for the presence of antibodies to Salmonella, Neospora caninum and Leptospira interrogans serovar hardjo in extensively managed unvaccinated dairy herds. A previous study documented a herd-level seroprevalence in bulk milk of 49%, 19% and 86% for Salmonella, Neospora caninum and leptospira interrogans serovar hardjo, respectively in the unvaccinated proportion of these 309 herds in 2009. Association analyses in the present study were carried out using multiple logistic regression models. Herds where cattle were purchased or introduced had a greater likelihood of being positive to leptospira interrogans serovar hardjo (P<0.01) and Salmonella (P<0.01). Larger herds had a greater likelihood of recording a positive bulk milk antibody result to leptospira interrogans serovar hardjo (P<0.05). Herds that practiced year round calving were more likely to be positive to Neospora caninum (P<0.05) compared to herds with a spring-calving season, with no difference in risk between herds that practiced split calving compared to herds that practiced spring calving. No association was found between presence of dogs on farms and prevalence of Neospora caninum possibly due to limited access of dogs to infected materials including afterbirths. The information from this study will assist in the design of suitable control programmes for the diseases under investigation in pasture-based livestock systems.

  9. The enzyme-linked immunosorbent assay (ELISA) as a serological test for detecting antibodies against Leptospira interrogans serovar hardjo in sheep.

    PubMed

    Adler, B; Faine, S; Gordon, L M

    1981-09-01

    The enzyme-liked immunosorbent assay (ELISA) was compared with the standard microscopic agglutination test (MAT) as a method for detecting antibodies against Leptospira interrogans serovar hardjo in sheep. Peak antibody levels detected by the 2 tests occurred at different times following experimental infection of sheep. In serums from flocks of sheep with naturally acquired infection there was a 95% correlation between MAT and ELISA with respect to the presence or absence of antibody to serovar hardjo, although the levels of correlation of the titres of the 2 tests was low. The 2 tests appeared to measure different antigen-antibody systems. The ELISA would be a useful test for screening large numbers of serums for antibodies to L. interrogans serovar hardjo.

  10. Characterization of Leptospira interrogans Serovars by Polymorphism Variable Number Tandem Repeat Analysis

    PubMed Central

    Rezasoltani, Sama; Dabiri, Hossein; Khaki, Pejvak; Rostami Nejad, Mohammad; Karimnasab, Nasim; Modirrousta, Shiva

    2015-01-01

    Background: Leptospirosis is recognized as a re-emerging infectious disease; therefore, understanding the epidemiology of the disease is vital for designing intervention programs and diminishing its transmission. Recently, Multilocus variable number tandem repeat analysis (MLVA) is used for segregating and identifying Leptospira serovars. The method has potential application in investigating the molecular epidemiology of Leptospira. Objectives: The propose of this study was genomic identification of pathogenic Leptospires in Iran by MLVA. Materials and Methods: Leptospira serovars were obtained from National Reference Laboratory of Leptospira at Razi Vaccine and Serum Research Institute, Karaj, Iran. Serovars were cultured into the liquid EMJH medium and incubated at 28˚C for 7 days. DNA of serovars was extracted using the phenol-chloroform method. PCR was performed with 5 selected variable number tandem repeat analysis (VNTR) loci. The amplified products were analyzed by agarose gel electrophoresis. The size of the amplified products was estimated by 100 bp ladder and sequencing analysis. Results: The saprophytic serovar showed no amplified fragments. PCR products in all pathogenic serovars were observed. The 12 reference serovars used for the development of technique displayed distinct patterns. Conclusions: Results showed that MLVA technique with its range of polymorphism is a good marker for identification of pathogenic serovars. Some VNTR loci are more powerful than the other ones with regard to differentiation. Serovars from the same geographical area have more genetic similarity than same serovars from different places. MLVA is a suitable technique for epidemiological survey. PMID:26568805

  11. Experimental infections of brush-tailed possums, common wombats and water rats with Leptospira interrogans serovars balcanica and hardjo.

    PubMed

    Durfee, P T; Presidente, P J

    1979-06-01

    Of 12 brush-tailed possums (Trichosurus vulpecula) inoculated with Leptospira interrogans serovar balcanica 11 developed migroagglutination (MA) antibody to jardjo antigen by 14 days postincubation (PI). Leptospiruria was observed in 2 possums 117 to 145 days PI. Of 6 possums inoculated with serovar hardjo 4 developed low short-lived titres by day 18 PI. Two of 3 wombats (Vombatus ursinus) inoculated with balcanica had high MA titres (greater than or equal to 1:128) by day 16 PI and leptospiruria occurred by day 16. One wombat inoculated with hardjo developed a low MA titre. Low transitory MA titres to hardjo were found in 1 of 3 water rats (Hydromys chrysogaster) after inoculation with balcanica and 1 of 2 given hardjo. Histopathological examination of kidneys revealed mild to moderately severe focal interstitial nephritis in 4 of 8 possums, in 2 wombats and in 2 water rats following experimental infection with balcanica. Similar lesions were observed in 2 of 4 possums, 1 wombat and 2 water rats following experimental infection with hardjo.

  12. SEROPREVALENCE OF NINE LEPTOSPIRA INTERROGANS SEROVARS IN WILD CARNIVORES, UNGULATES, AND PRIMATES FROM A ZOO POPULATION IN A METROPOLITAN REGION OF CHILE.

    PubMed

    Moreno-Beas, Eduardo; Abalos, Pedro; Hidalgo-Hermoso, Ezequiel

    2015-12-01

    Serum samples from 130 individuals representing 42 species of carnivores, ungulates, and primates from a population of captive mammals in Metropolitan Region in Chile were tested for antibodies against nine serovars of Leptospira interrogans using the microscopic agglutination test. Ten percent of the animals were seropositive to one or more serovars. Seroprevalence was significantly higher in ungulates (20.4%) compared to carnivores (3.8%) and primates (3.4%). There were no significant differences in seroprevalence among sex and age ranges. The most frequent serovar detected was Autumnalis, present in 53.4% of antibody-positive animals. Most positive animals had titers of ≤1 : 200, except for a maned wolf ( Chrysocyon brachyurus ) with titers of 1 : 400 against serovar Hardjo. To the authors' knowledge, this is the first report of Leptospira exposure detected in native endangered pudu ( Pudu puda ) and the first confirmation of exposure to L. interrogans in captive wild mammals in Chile. Leptospirosis should be considered as a differential diagnosis in future disease presentation for hepatitis or abortions in captive mammals in Chile.

  13. Leptospira interrogans serovar canicola: a causal agent of sow abortions in Arequipa, Peru.

    PubMed

    Paz-Soldán, S V; Dianderas, M T; Windsor, R S

    1991-11-01

    An outbreak of abortions, stillbirths, mummified piglets and neonatal deaths in a pig herd in Arequipa, Peru is described. A total of 31 of 240 sows aborted between May and September 1988. When sera were examined 12 of 14 had very high titres of antibody to canicola PC125 and canicola Hond Utrecht, but there were also high titres of antibody to other leptospiral serovars. A detailed investigation was made and serovar canicola PC125 was isolated from the urine of four sows which had aborted and the kidney of one slaughter pig. Antibodies to various serovars of Leptospira were demonstrated in 11 of 17 sows which had aborted, two of six sows which had normal litters, nine of 18 boars, four of 39 slaughter pigs and four of 14 workers on the farm. The outbreak was brought under control by treatment and vaccination coupled with a thorough cleaning of the farm and control of the wild animal population. It is suggested that the infection was brought onto the farm by wild animals and that the disease is more common in Arequipa than was previously supposed.

  14. Prozone effects in microscopic agglutination tests for leptospirosis in the sera of mice infected with the pathogenic Leptospira interrogans serovar Canicola

    PubMed Central

    Shimabukuro, Fabio Hiroto; da Costa, Veruska Maia; da Silva, Rodrigo Costa; Langoni, Hélio; da Silva, Aristeu Vieira; de Carvalho, Lídia Raquel; Domingues, Paulo Francisco

    2013-01-01

    Mice experimentally infected with a pathogenic strain of Leptospira interrogans serovar Canicola produced false negative results (prozone effect) in a microscopic agglutination test (MAT). This prozone effect occurred in several serum samples collected at different post-infection times, but it was more prominent in samples collected from seven-42 days post-infection and for 1:50 and 1:100 sample dilutions. This phenomenon was correlated with increased antibody titres in the early post-infection phase. While prozone effects are often observed in serological agglutination assays for the diagnosis of animal brucellosis and human syphilis, they are not widely reported in leptospirosis MATs. PMID:23903987

  15. Bayesian inference for within-herd prevalence of Leptospira interrogans serovar Hardjo using bulk milk antibody testing.

    PubMed

    Lewis, Fraser I; Gunn, George J; McKendrick, Iain J; Murray, Fiona M

    2009-10-01

    Leptospirosis is the most widespread zoonosis throughout the world and human mortality from severe disease forms is high even when optimal treatment is provided. Leptospirosis is also one of the most common causes of reproductive losses in cattle worldwide and is associated with significant economic costs to the dairy farming industry. Herds are tested for exposure to the causal organism either through serum testing of individual animals or through testing bulk milk samples. Using serum results from a commonly used enzyme-linked immunosorbent assay (ELISA) test for Leptospira interrogans serovar Hardjo (L. hardjo) on samples from 979 animals across 12 Scottish dairy herds and the corresponding bulk milk results, we develop a model that predicts the mean proportion of exposed animals in a herd conditional on the bulk milk test result. The data are analyzed through use of a Bayesian latent variable generalized linear mixed model to provide estimates of the true (but unobserved) level of exposure to the causal organism in each herd in addition to estimates of the accuracy of the serum ELISA. We estimate 95% confidence intervals for the accuracy of the serum ELISA of (0.688, 0.987) and (0.975, 0.998) for test sensitivity and specificity, respectively. Using a percentage positivity cutoff in bulk milk of at most 41% ensures that there is at least a 97.5% probability of less than 5% of the herd being exposed to L. hardjo. Our analyses provide strong statistical evidence in support of the validity of interpreting bulk milk samples as a proxy for individual animal serum testing. The combination of validity and cost-effectiveness of bulk milk testing has the potential to reduce the risk of human exposure to leptospirosis in addition to offering significant economic benefits to the dairy industry.

  16. Multiple-locus variable-number tandem repeat analysis (MLVA) of Leptospira interrogans serovar Pomona from Argentina reveals four new genotypes.

    PubMed

    Pavan, María Elisa; Cairó, Fabián; Brihuega, Bibiana; Samartino, Luis

    2008-01-01

    Outbreaks of leptospirosis occur regularly in Argentina, but little is known about their epidemiological relationships. We have analyzed the genetic diversity of a collection of 16 strains of Leptospira interrogans serovar Pomona isolated from animals and humans in Argentina during the past 45 years. Genotyping was performed by multiple-locus variable-number tandem repeat analysis (MLVA) using the loci VNTR4, VNTR7, VNTR9, VNTR10, VNTR19, VNTR23 and VNTR31, as described by Majed et al. [Identification of variable-number tandem-repeat loci in Leptospira interrogans sensu stricto. J Clin Microbiol 2005;43:539-45]. Clustering analysis revealed four new distinct MLVA genotypes, with a dominant one. Strains with this genotype were consistently isolated since 1960 to the present, mainly from cows and pigs, but also from humans, representing 75% of the total strains studied. These strains coexisted temporally and geographically with isolates presenting the other new genotypes. VNTR4 locus, with four different alleles, presented the highest diversity between the VNTR loci analyzed. MLVA patterns obtained will be useful for future diagnostic and epidemiological tracing analysis.

  17. Effect of exposure to Neospora caninum, Salmonella, and Leptospira interrogans serovar Hardjo on the economic performance of Irish dairy herds.

    PubMed

    O' Doherty, E; Sayers, R; O' Grady, L; Shalloo, L

    2015-04-01

    The objective of the current study was to quantify the effects of exposure to Salmonella, Neospora caninum, and Leptospira interrogans serovar Hardjo (L. hardjo) on dairy farm profitability and to simulate the effect of vaccination for Salmonella and L. hardjo on dairy farm profitability. The production effects associated with exposure to each of these pathogens in study herds were defined under 3 categories: (1) milk production effects, (2) reproduction effects (including culling), and (3) mortality effects. The production effects associated with exposure to Salmonella, N. caninum, and L. hardjo were incorporated into the Moorepark Dairy Systems Model. In the analysis, herds negative for exposure to Salmonella, N. caninum, and L. hardjo were assumed baseline herds, with all results presented relative to this base. In simulations examining the effect of vaccination for Salmonella and L. hardjo on farm profitability, vaccinated herds (vaccination costs included) were considered as baseline herds and results were presented relative to this base. Total annual profits in unvaccinated herds were reduced by €77.31, €94.71, and €112.11 per cow at milk prices of €0.24, €0.29, and €0.34/L, respectively, as a result of exposure to Salmonella. In the current study, herds positive for exposure to Salmonella recorded a 316-kg reduction in milk yield, whereas no association was detected between exposure to N. caninum or L. hardjo and milk production. Exposure to both N. caninum and L. hardjo was associated with compromised reproductive performance. Herds positive for exposure to N. caninum and Salmonella had greater rates of adult cow mortality and calf mortality, respectively. Vaccination for both Salmonella and L. hardjo was associated with improved performance in study herds. Exposure to N. caninum resulted in a reduction in annual farm profits of €11.55, €12, and €12.44 per cow at each milk price, whereas exposure to L. hardjo resulted in a reduction in

  18. In Vivo-Expressed Proteins of Virulent Leptospira interrogans Serovar Autumnalis N2 Elicit Strong IgM Responses of Value in Conclusive Diagnosis

    PubMed Central

    Raja, Veerapandian; Shanmughapriya, Santhanam; Kanagavel, Murugesan; Artiushin, Sergey C.; Velineni, Sridhar; Timoney, John F.

    2015-01-01

    Leptospirosis is a serious zoonosis that is underdiagnosed because of limited access to laboratory facilities in Southeast Asia, Central and South America, and Oceania. Timely diagnosis of locally distributed serovars of high virulence is crucial for successful care and outbreak management. Using pooled patient sera, an expression gene library of a virulent Leptospira interrogans serovar Autumnalis strain N2 isolated in South India was screened. The identified genes were characterized, and the purified recombinant proteins were used as antigens in IgM enzyme-linked immunosorbent assay (ELISA) either singly or in combination. Sera (n = 118) from cases of acute leptospirosis along with sera (n = 58) from healthy subjects were tested for reactivity with the identified proteins in an ELISA designed to detect specific IgM responses. We have identified nine immunoreactive proteins, ArgC, RecA, GlpF, FliD, TrmD, RplS, RnhB, Lp28.6, and Lrr44.9, which were found to be highly conserved among pathogenic leptospires. Apparently, the proteins ArgC, RecA, GlpF, FliD, TrmD, and Lrr44.9 are expressed during natural infection of the host and undetectable in in vitro cultures. Among all the recombinant proteins used as antigens in IgM ELISA, ArgC had the highest sensitivity and specificity, 89.8% and 95.5%, respectively, for the conclusive diagnosis of leptospirosis. The use of ArgC and RecA in combination for IgM ELISA increased the sensitivity and specificity to 95.7% and 94.9%, respectively. ArgC and RecA thus elicited specific IgM responses and were therefore effective in laboratory confirmation of Leptospira infection. PMID:26607308

  19. Detection of leptospiral antigen (L. interrogans serovar copenhageni serogroup Icterohaemorrhagiae) by immunoelectron microscopy in the liver and kidney of experimentally infected guinea-pigs.

    PubMed Central

    De Brito, T.; Prado, M. J.; Negreiros, V. A.; Nicastri, A. L.; Sakata, E. E.; Yasuda, P. H.; Santos, R. T.; Alves, V. A.

    1992-01-01

    Guinea-pigs were experimentally infected with L. interrogans serovar copenhageni serogroup Icterohaemorrhagiae and their liver and kidney were studied by immunoelectron microscopy using the post embedding indirect immunogold labelling technique. Primary antibody was a purified rabbit anti-serum produced against the same leptospiral strain used in the inoculum. Gold-labelled leptospiral antigen (LAg) was found close to cell membranes of hepatocytes, kidney tubular cells and endothelial cells of the interstitial capillaries of the kidney. Afterwards it was internalized by hepatic and tubular cells, and eventually found in lysosomes. Phagolysosomes of Kupffer cells were also found to contain remnants of degraded leptospires and gold-labelled LAg. Gold-labelled intact leptospires were detected at the enlarged intercellular spaces between hepatocytes at the areas of hepatic cell plate disarray, showing the potential for leptospiral migration during the septicaemic phase of the disease potentially contributing to the pathogenesis of the lesions. The affinity of leptospiral antigenic material for cell membranes suggests an initial interaction with cell surface proteins followed by its internalization and cell damage. The nature of antigenic material detected, however, remains undefined; it may be a toxin, an enzyme or any other factor/s involved in leptospiral virulence. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 PMID:1419779

  20. Genomic Analysis of a New Serovar of Leptospira weilii Serogroup Manhao

    PubMed Central

    Zheng, Huajun; Zhang, Ying; Wang, Yuezhu; Zhang, Jinlong; Li, Zhe; Cui, Shenghui; Xin, Xiaofang; Ye, Qiang; Chang, Yung-Fu; Wang, Junzhi

    2017-01-01

    Leptospirosis, caused by pathogenic Leptospira spp., is recognized as an important emerging zoonotic disease throughout the world. In this study, multiple approaches were used to characterize the recently discovered serovar Heyan strain L231. This strain can infect guinea pigs and belonged to the pathogenic species L. weilii. Genome sequencing analysis revealed the draft genome of 4.2 M bp with a G+C content of 40.67% for strain L231, and a total of 4,794 ORFs were identified. The strain L231 genome was found to have a larger LPS biosynthesis locus than that of strains L. interrogans serovar Lai and L. borgpetersenii serovar Hardjobovis. Phylogenomic reconstructions showed that the evolutionary position of L. weilii serovar Heyan was different from that of other serovars from serogroup Manhao. These findings may lead us to a better understanding of Leptospira pathogenesis and evolution. PMID:28210253

  1. Leptospira interrogans in the genital tract of sheep. Research on ewes and rams experimentally infected with serovar hardjo (hardjobovis).

    PubMed

    Farina, R; Cerri, D; Renzoni, G; Andreani, E; Mani, P; Ebani, V; Pedrini, A; Nuvoloni, R

    1996-07-01

    To verify if Leptospira hardjo can colonize the male and female genital organs of sheep, 9 animals (6 non pregnant ewes and 3 mature rams) were infected with a strain of L. hardjobovis recently recovered from the kidneys of a seropositive ewe. Postinfection controls (bacteriologic, serologic, immunohistochemistry and electron microscopy) failed to disclose the presence of leptospires in the uterus and oviducts, testicles, epididymis, prostate and bulbourethral glands of animals used for the experiment and slaughtered from 37 to 242 postinfection days. All animals showed a renal localization of L. hardjobovis lasting for the entire period of the study (over 8 months). These results emphasize the important role of sheep as maintenance hosts of the serovar.

  2. Safety and efficacy of a new octavalent combined Erysipelas, Parvo and Leptospira vaccine in gilts against Leptospira interrogans serovar Pomona associated disease and foetal death.

    PubMed

    Jacobs, A A C; Harks, F; Hoeijmakers, M; Collell, M; Segers, R P A M

    2015-07-31

    The safety and protective efficacy of a new octavalent combination vaccine containing inactivated Erysipelothrix rhusiopathiae, Parvovirus, and Leptospira interrogans (sensu lato) serogroups Canicola, Icterohaemorrhagiae, Australis (Bratislava), Grippotyphosa, Pomona and Tarassovi - Porcilis(®) Ery+Parvo+Lepto - was evaluated in laboratory studies and under field conditions. The safety (2× overdose and repeated dose) was tested in 26 gilts. In this study, neither vaccine related temperature increase nor other systemic reactions were observed after intramuscular vaccination. No local reactions were observed except for one animal that had a small local reaction (2cm diameter) that lasted for 5 days after the third vaccination. Efficacy was tested in 40 gilts. A group of 20 gilts was vaccinated at 20 and 24 weeks of age with Porcilis(®) Ery+Parvo+Lepto and a group of 20 age- and source-matched animals served as the control group. The gilts were inseminated at 41 weeks or 66 weeks of age and were challenged with serovar Pomona 10 weeks after insemination, corresponding to 6 months (n=2×10) and 12 months (n=2×10) after the last vaccination. After both the 6- and 12-month challenges the control animals developed clinical signs (fever, lethargy and anorexia) and leptospiraemia as determined by positive blood culture. In addition, both the 6- and 12-month challenges resulted in death of 21% and 27% of the total number of foetuses in the control groups, respectively. Clinical signs and leptospiraemia were statistically significantly lower in vaccinated gilts after both the 6- and 12-month challenges. In addition, foetal death was statistically significantly lower (3% and 2%, respectively) in vaccinated gilts after both the 6- and 12 month challenges. The vaccine was tested further under field conditions on a Portuguese farm with a history of an increasing abortion rate associated with a Leptospira serovar Pomona infection (confirmed by PCR and serology). This study was

  3. [Construction of eukaryotic recombinant vector and expression in COS7 cell of LipL32-HlyX fusion gene from Leptospira serovar Lai].

    PubMed

    Huang, Bi; Bao, Lang; Zhong, Qi; Zhang, Huidong; Zhang, Ying

    2009-04-01

    This study was conducted to construct eukaryotic recombinant vector of LipL32-HlyX fusion gene from Leptospira serovar Lai and express it in mammalian cell. Both of LipL32 gene and HlyX gene were amplified from Leptospira strain O17 genomic DNA by PCR. Then with the two genes as template, LipL32-HlyX fusion gene was obtained by SOE PCR (gene splicing by overlap extension PCR). The fusion gene was then cloned into pcDNA3.1 by restriction nuclease digestion. Having been transformed into E. coli DH5alpha, the recombiant plasmid was identified by restriction nuclease digestion, PCR analysis and sequencing. The recombinant plasmid was then transfected into COS7 cell whose expression was detected by RT-PCR and Western blotting analysis. RT-PCR amplified a fragment about 2000 bp and Western blotting analysis found a specific band about 75 KD which was consistent with the expected fusion protein size. In conclusion, the successful construction of eukaryotic recombinant vector containing LipL32-HlyX fusion gene and the effective expression in mammalian have laid a foundation for the application of Leptospira DNA vaccine.

  4. Global Proteome Analysis of Leptospira interrogans

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Comparative global proteome analyses were performed on Leptospira interrogans serovar Copenhageni grown under conventional in vitro conditions and those mimicking in vivo conditions (iron limitation and serum presence). Proteomic analyses were conducted using iTRAQ and LC-ESI-tandem mass spectrometr...

  5. Antibodies against Leptospira interrogans in California sea lion pups from Gulf of California.

    PubMed

    Godínez, C R; Zelaya de Romillo, B; Aurioles-Gamboa, D; Verdugo-Rodríguez, A; Rodríguez-Reyes, E A; De la Peña-Moctezuma, A

    1999-01-01

    One hundred and twenty-five serum samples from California sea lion (Zalophus californianus californianus) pups, and one from an adult female from eight reproductive rookeries located in seven islands in the Gulf of California (Mexico), were collected during the 1994-96 reproductive seasons. These were tested for antibodies to 19 serovars of Leptospira interrogans using a Microscopic Agglutination Test (MAT). Forty-one samples (32%) had antibody levels from 1:20 to 1:320 to one or more serovars. The most frequently detected serotypes were Leptospira interrogans hardjo (n = 13), cynopteri (8), ballum (6), and szwajizak (5). Serovars with the highest prevalence were Leptospira interrogans hardjo and serjoe (1:320), ballum (1:160), and cynopteri, girppotyphosa, and tarassovi (1:80). Based on these results, exposure of sea lions to L. interrogans serovar hardjo seems to be relatively common among colonies located in the islands of the Gulf of California in contrast with those located on the Pacific coast, where the most frequently detected serovar is L. interrogans serovar pomona.

  6. Role of sph2 Gene Regulation in Hemolytic and Sphingomyelinase Activities Produced by Leptospira interrogans

    PubMed Central

    Narayanavari, Suneel A.; Lourdault, Kristel; Sritharan, Manjula; Haake, David A.; Matsunaga, James

    2015-01-01

    Pathogenic members of the genus Leptospira are the causative agents of leptospirosis, a neglected disease of public and veterinary health concern. Leptospirosis is a systemic disease that in its severest forms leads to renal insufficiency, hepatic dysfunction, and pulmonary failure. Many strains of Leptospira produce hemolytic and sphingomyelinase activities, and a number of candidate leptospiral hemolysins have been identified based on sequence similarity to well-characterized bacterial hemolysins. Five of the putative hemolysins are sphingomyelinase paralogs. Although recombinant forms of the sphingomyelinase Sph2 and other hemolysins lyse erythrocytes, none have been demonstrated to contribute to the hemolytic activity secreted by leptospiral cells. In this study, we examined the regulation of sph2 and its relationship to hemolytic and sphingomyelinase activities produced by several L. interrogans strains cultivated under the osmotic conditions found in the mammalian host. The sph2 gene was poorly expressed when the Fiocruz L1-130 (serovar Copenhageni), 56601 (sv. Lai), and L495 (sv. Manilae) strains were cultivated in the standard culture medium EMJH. Raising EMJH osmolarity to physiological levels with sodium chloride enhanced Sph2 production in all three strains. In addition, the Pomona subtype kennewicki strain LC82-25 produced substantially greater amounts of Sph2 during standard EMJH growth than the other strains, and sph2 expression increased further by addition of salt. When 10% rat serum was present in EMJH along with the sodium chloride supplement, Sph2 production increased further in all strains. Osmotic regulation and differences in basal Sph2 production in the Manilae L495 and Pomona strains correlated with the levels of secreted hemolysin and sphingomyelinase activities. Finally, a transposon insertion in sph2 dramatically reduced hemolytic and sphingomyelinase activities during incubation of L. interrogans at physiologic osmolarity

  7. [Presence of IgM antibodies for Leptospira interrogans in wild animals from Tocantins State, 2002].

    PubMed

    de Souza Júnior, Milton Formiga; Lobato, Zélia Inês Portela; Lobato, Francisco Carlos Faria; Moreira, Elvio Carlos; de Oliveira, Rogério Rodrigues; Leite, Geysa Goulart; Freitas, Theonys Diógenes; de Assis, Ronnie Antunes

    2006-01-01

    Four hundred and twenty-seven serum samples of wild animals were tested against 18 serovars of Leptospira interrogans. Of 286 samples of Cebus apella, 46 (16.1%) were positive for the serovars pomona, brasiliensis, mini, swajizak, grippotyphosa, sarmin, fluminense, autumnalis, hebdomadis, guaratuba, javanica and icterohaemorrhagiae. Of 82 samples of Alouatta caraya, 2 (2.4%) were positive for the serovars mangus and fluminense. Of 31 samples of Nasua nasua, 4 (12.9%) were positive for the serovars fluminense and javanica, and of 10 samples of Cerdocyon thous, 2 (20 %) were positive for the serovars fluminense and brasiliensis. Seven samples of Dasyprocta sp, 6 of Tamandua tetradactyla and 5 of Euphractus sexcintus did not present reactivity.

  8. Seroprevalence and risk factors associated with within-flock transmission of Leptospira interrogans in transhumant farming systems in Mexico.

    PubMed

    Arteaga-Troncoso, G; Jiménez-Estrada, J M; Montes De Oca-Jimenez, R; López-Hurtado, M; Luna-Alvarez, M; Hernandez-Andrade, L; Moreno-Alfaro, A; Galan-Herrera, J F; Guerra-Infante, F M

    2015-10-01

    A number of recent reports emphasize the risk of zoonotic diseases and the high degree of prevalence of asymptomatic animals infected with Leptospira interrogans. This report sought to assess the prevalence of antibodies to certain serovars of L. interrogans, and to describe the association between seropositivity and risk factors associated with within-flock transmission in a mountainous region of Mexico. Overall seroprevalence to L. interrogans was 54·5% (95% confidence interval 48·3-60·7); the most frequent serovar was Icterohaemorrhagiae. The accumulation of placentas and fetuses at a site close to lambing paddocks can play a significant role as a risk factor for within-flock transmission of L. interrogans in transhumant farming systems in the municipality of Xalatlaco. The high prevalence of L. interrogans antibodies supports the hypothesis that natural foci of this zoonosis are present in sheep flocks in this area. These findings emphasize the need for planning and implementation of control programmes for ovine leptospirosis in Mexico and elsewhere.

  9. Cytotoxic activities of Leptospira interrogans hemolysin SphH as a pore-forming protein on mammalian cells.

    PubMed

    Lee, Seoung Hoon; Kim, Sangduk; Park, Seung Chul; Kim, Min Ja

    2002-01-01

    Leptospirosis is a spirochetal zoonosis that causes an acute febrile systemic illness in humans. Leptospira sp. hemolysins have been shown to be virulence factors for the pathogenesis of leptospirosis. Previously, we cloned a hemolysin SphH of Leptospira interrogans serovar lai, a homologue of L. borgpetersenii sphingomyelinase (SphA), from a genomic library (S. H. Lee, K. A. Kim, Y. K. Kim, I. W. Seong, M. J. Kim, and Y. J. Lee, Gene 254:19-28, 2000). Escherichia coli lysate harboring the sphH showed high hemolytic activities on sheep erythrocytes. However, it neither showed sphingomyelinase nor phospholipase activities, in contrast to SphA which was known to have sphingomyelinase activity. Interestingly, the SphH-mediated hemolysis on erythrocytes was osmotically protected by PEG 5000, suggesting that the SphH might have caused pore formation on the erythrocyte membrane. In the present study, we have prepared the Leptospira hemolysin SphH and investigated its hemolytic and cytotoxic activities on mammalian cells. SphH was shown to be a pore-forming protein on several mammalian cells: When treated with the SphH, the sheep erythrocyte membranes formed pores, which were morphologically confirmed by transmission electron microscopy. Furthermore, the SphH-mediated cytotoxicities on mammalian cells were demonstrated by the release of LDH and by inverted microscopic examinations. Finally, the immune serum against the full-length hemolysin could effectively neutralize the SphH-mediated hemolytic and cytotoxic activities. In conclusion, these results suggest that the virulence of Leptospira SphH was due to the pore formation on mammalian cell membranes.

  10. Expansion of the in vitro assay for Leptospira potency testing to other serovars: case study with Leptospira Hardjo.

    PubMed

    Alt, David P; Wilson-Welder, Jennifer

    2013-09-01

    Evaluation of leptospiral vaccines for potency against Leptospira interrogans serovars Pomona, Icterohaemorrhagiae, Canicola, and Grippotyphosa is accomplished using the hamster potency test method described in 9 CFR 113.101-104. Applicability of this method to evaluation of bacterins developed for immunization against infection with L. interrogans serovar Hardjo or Leptospira borgpetersenii serovar Hardjo is complicated by several issues. Information from research on target host animal efficacy studies and evaluation of the immune response elicited using effective whole-cell bacterin formulations have revealed problems in relating these studies to either hamster-based or other potency testing methods. Future work on serovar Hardjo vaccines employing recombinant proteins will require preliminary testing methods in models other than the host animal. These models may also prove applicable to evaluation of potency for protein-based vaccines. Both an acute lethal infection model and a chronic infection model have been developed using two different strains of serovar Hardjo and will be described.

  11. Phenotypic and Molecular Characterization of Leptospira interrogans Isolated from Canis familiaris in Southern Brazil.

    PubMed

    Jorge, Sérgio; Monte, Leonardo G; De Oliveira, Natasha R; Collares, Thais F; Roloff, Bárbara C; Gomes, Charles K; Hartwig, Daiane D; Dellagostin, Odir A; Hartleben, Cláudia P

    2015-10-01

    Leptospirosis is a zoonotic disease caused by pathogenic spirochetes from the genus Leptospira, which includes 20 species and more than 300 serovars. Canines are important hosts of pathogenic leptospires and can transmit the pathogen to humans via infected urine. Here, we report the phenotypic and molecular characterization of Leptospira interrogans isolated from Canis familiaris in Southern Brazil. The isolated strain was characterized by variable-number tandem-repeats analysis as L. interrogans, serogroup Icterohaemorrhagiae. In addition, the isolate was recognized by antibodies from human and canine serum samples previously tested by microscopic agglutination test. Ultimately, the expression of membrane-associated antigens (LipL32 and leptospiral immunoglobulin-like proteins) from pathogenic leptospires using monoclonal antibodies was detected by indirect immunofluorescence assay. In conclusion, identification of new strains of Leptospira can help in the diagnosis and control of leptospirosis.

  12. First isolation of Leptospira interrogans from Lycalopex griseus (South American gray fox) in Argentina shows new MLVA genotype.

    PubMed

    Scialfa, Exequiel; Brihuega, Bibiana; Venzano, Agustín; Morris, Winston Eduardo; Bolpe, Jorge; Schettino, Mateo

    2013-01-01

    To identify carriers of Leptospira spp. in Argentina, wild animals were trapped in Buenos Aires Province during three nights, capturing 12 Didelphis albiventris (white-eared opossum), six Chaetophractus villosus (big hairy armadillo), five Lycalopex griseus (South American gray fox), and two Conepatus chinga (Molina's hog-nosed skunk). All were tested by microscopic agglutination test, and five (two gray foxes, two armadillos, and one skunk) were positive for Leptospira interrogans serovars Canicola and Icterohaemorrhagiae, L. borgpetersenii serovar Castellonis, and L. kirschneri serovar Grippotyphosa, at titers of 1:50 and 1:100. Kidney tissue from all animals was cultured, and one isolate of L. interrogans from a gray fox was obtained. Hamsters inoculated with the isolate died after 6 days with no macroscopic lesions at necropsy. However, histologic examination revealed glomerulonephritis, interstitial nephritis, and pneumonia. The Leptospira strain from the South American gray fox was analyzed serologically and its pathogenicity was established. Genotyping through multiple-locus variable-number tandem repeat analysis showed that the strain was a new genotype related to the L. interrogans serogroup Icterohaemorrhagiae.

  13. Response of Leptospira interrogans to physiologic osmolarity: relevance in signaling the environment-to-host transition.

    PubMed

    Matsunaga, James; Lo, Miranda; Bulach, Dieter M; Zuerner, Richard L; Adler, Ben; Haake, David A

    2007-06-01

    Transmission of pathogenic Leptospira between mammalian hosts usually involves dissemination via soil or water contaminated by the urine of carrier animals. The ability of Leptospira to adapt to the diverse conditions found inside and outside the host is reflected in its relatively large genome size and high percentage of signal transduction genes. An exception is Leptospira borgpetersenii serovar Hardjo, which is transmitted by direct contact and appears to have lost genes necessary for survival outside the mammalian host. Invasion of host tissues by Leptospira interrogans involves a transition from a low osmolar environment outside the host to a higher physiologic osmolar environment within the host. Expression of the lipoprotein LigA and LigB adhesins is strongly induced by an upshift in osmolarity to the level found in mammalian host tissues. These data suggest that Leptospira utilizes changes in osmolarity to regulate virulence characteristics. To better understand how L. interrogans serovar Copenhageni adapts to osmolar conditions that correspond with invasion of a mammalian host, we quantified alterations in transcript levels using whole-genome microarrays. Overnight exposure in leptospiral culture medium supplemented with sodium chloride to physiologic osmolarity significantly altered the transcript levels of 6% of L. interrogans genes. Repressed genes were significantly more likely to be absent or pseudogenes in L. borgpetersenii, suggesting that osmolarity is relevant in studying the adaptation of L. interrogans to host conditions. Genes induced by physiologic osmolarity encoded a higher than expected number of proteins involved in signal transduction. Further, genes predicted to encode lipoproteins and those coregulated by temperature were overrepresented among both salt-induced and salt-repressed genes. In contrast, leptospiral homologues of hyperosmotic or general stress genes were not induced at physiologic osmolarity. These findings suggest that

  14. Serosurvey for canine distemper virus, canine adenovirus, Leptospira interrogans, and Toxoplasma gondii in free-ranging canids in Scandinavia and Svalbard.

    PubMed

    Akerstedt, Johan; Lillehaug, Atle; Larsen, Inger-Lise; Eide, Nina E; Arnemo, Jon M; Handeland, Kjell

    2010-04-01

    Prevalence of antibodies reactive to canine distemper virus (CDV), canine adenovirus type 1 (CAV-1), Leptospira interrogans serovars Canicola and Icterohaemorrhagiae, and Toxoplasma gondii were examined in free-ranging Scandinavian canids. Sampling included 275 red foxes (Vulpes vulpes) from mainland Norway, 60 arctic foxes (Vulpes lagopus) from the high-arctic islands of Svalbard, and 98 wolves (Canis lupus) from the joint Swedish-Norwegian population. Methods used included virus neutralization tests for CDV and CAV-1, a microscopic agglutination test for L. interrogans, and a direct agglutination test for T. gondii. High prevalence of antibody to CAV-1 was identified in red foxes (59.6%), wolves (67.7%), and arctic foxes (37.8%). The prevalence of antibody to CDV varied between 9.6% and 12.3% in the three species. Antibodies to L. interrogans serovar Icterohaemorrhagiae were found in 9.9% of the red foxes and 8.4% of the wolves sampled, whereas no antibody-positive arctic foxes were found. All animals were antibody-negative for L. interrogans serovar Canicola. Antibodies to T. gondii were found in 66.9, 51.7, and 18.6% of red foxes, arctic foxes and wolves, respectively. Significantly more adults than juveniles were antibody-positive for CDV in red foxes and arctic foxes, for CAV-1 in wolves, and for T. gondii in red foxes and wolves. There was a general tendency for adult female red foxes to have a higher prevalence of antibodies for CDV than adult males; this difference was statistically significant. The results indicate that CDV and CAV-1 are endemic in red foxes and wolves on the Scandinavian mainland and in arctic foxes on Svalbard. Although infection with L. interrogans serovar Icterohaemorrhagiae was relatively common in wild canids on mainland Norway, it was not found on Svalbard, where the maintenance host (Rattus norvegicus) is absent. All three species are commonly exposed to T. gondii through predation on infected intermediate hosts.

  15. Seasonal prevalence of antibodies to Leptospira interrogans in Antillean manatees from a landlocked lake in Tabasco, Mexico.

    PubMed

    Aragón-Martínez, Arianna; Olivera-Gómez, León D; Jiménez-Domínguez, Darwin

    2014-07-01

    Factors that alter the dynamics of ecologic systems can influence transmission of infectious diseases and may lead to decreases in natural populations. Leptospirosis is a cosmopolitan disease of zoonotic importance that affects most mammals. At the southern Gulf of Mexico, Antillean manatees (Trichechus manatus manatus) inhabit highly variable environments, with extended floods during the rainy season and drought conditions during the dry season that affect food availability and the thermal environment for manatees. We tested for changes in prevalence and titers of antibodies to 12 serovars of Leptospira interrogans in manatees between dry and rainy seasons. We determined titers for L. interrogans through microscopic agglutination tests (MAT) from 10 manatees, six during the dry season (DS), and six during the rainy season (RS) in Laguna de las Ilusiones, a landlocked lake hosting a population of about 20 manatees. All individuals were antibody positive (titers ≥ 100) to at least one serovar. The serovars bataviae, bratislava, canicola, and icterohaemorrhagiae had overall prevalences ≥ 50%; bataviae, bratislava, and canicola had prevalences ≥ 50% during both seasons. Serovars icterohaemorrhagiae and pyrogenes had prevalences ≥ 50% during DS and pomona, tarassovi, wolfii, and autumnalis during RS. Significant differences in prevalence between seasons were found for pomona, tarassovi, and autumnalis. Titers of tarassovi, wolfii, autumnalis, and bataviae were significantly higher during RS. There was a high prevalence of L. interrogans during the RS independent of high availability of plant foods, coinciding with the epizootiology of the bacteria that are endemic to tropical regions. Another factor possibly influencing prevalence is high anthropogenic pressure at the lake, causing an increase in potential sources of infection. Because of possible cross-reaction in MAT, further research is needed on the molecular discrimination of serovars in animals in the

  16. Risk factors associated with prevalence of antibodies to Leptospira interrogans in a metapopulation of black-tailed prairie dogs in Mexico.

    PubMed

    Montiel-Arteaga, Ana; Atilano, Daniel; Ayanegui, Alejandra; Ceballos, Gerardo; Suzán, Gerardo

    2015-01-01

    Interest in the study of infectious diseases of wildlife has grown in recent decades and now focuses on understanding host-parasite dynamics and factors involved in disease occurrence. The black-tailed prairie dog (Cynomys ludovicianus) is a useful species for this type of investigation because it lives in heterogeneous landscapes where human activities take place, and its populations are structured as a metapopulation. Our goal was to determine if colony area, density, and proximity to human settlements are associated with prevalence of antibodies to Leptospira interrogans in black-tailed prairie dogs of northwestern Chihuahua State, Mexico. We captured 266 prairie dogs in 11 colonies in 2009 and analyzed 248 serum samples with the microscopic agglutination test (MAT) for antibody to any of the 12 pathogenic serovars of L. interrogans. Serologically positive test results for only serovars Bratislava, Canicola, Celledoni, and Tarassovi were considered for statistical analysis. Almost 80% of sera were positive for at least one pathogenic serovar (MAT titer ≥1∶80). The highest recorded antibody prevalences were to serovars Bratislava and Canicola. Correlation analysis showed a negative relationship between L. interrogans antibody prevalence and colony area (r = -0.125, P<0.005), suggesting that animals living in larger colonies were at a lower risk than those in smaller colonies. The correlation between the serovar Canicola and distance was negative (r = -0.171, P<0.007), and this relationship may be explained by the presence of domestic dogs associated with human dwellings. This is the first study of Leptospira spp. antibody prevalence in prairie dogs, and it provides valuable insights into the dynamics of leptospirosis in threatened wildlife species. Further studies are needed to evaluate the impact of Leptospira serovars in metapopulations of prairie dogs and other domestic and wild mammals in grassland communities.

  17. Immunological and molecular characterization of Leptospira interrogans isolated from a bovine foetus.

    PubMed

    Monte, Leonardo Garcia; Ridieri, Karine Forster; Jorge, Sérgio; Oliveira, Natasha Rodrigues; Hartwig, Daiane Drawanz; Amaral, Marta Gonçalves; Hartleben, Cláudia Pinho; Dellagostin, Odir Antonio

    2015-06-01

    Cattle are commonly infected with pathogenic leptospires, and similarly to rodents, they excrete the bacteria in their urine and can transmit the pathogen from animal to animal or animal to human. Thus, surveillance and monitoring systems for detection of new Leptospira serovars are important for the control of leptospirosis. Here, we report the isolation of a spirochete from a stillborn bovine foetus and its characterization by immunological and molecular techniques. A variable number tandem repeat profile using seven discriminatory primers identified the spirochete as belonging to species Leptospira interrogans serogroup Australis serovar Muenchen. A phenotypic analysis using monoclonal antibodies (mAbs) against leptospiral membrane-associated proteins confirmed the expression of important virulence and pathogenicity factors (LipL32 and LigBrep). Out of 120 reference sera tested, 22 positive (36.66%) and 9 negative (15%) also reacted with the new isolate. Furthermore, the serovar Muenchen isolate was virulent in hamster model. The animal inoculated developed acute lethal infection characterized by hepatic, pulmonary and renal lesions. Local isolates exhibited unique characteristics that differed from those of reference strains; therefore, isolation of leptospires is useful in the surveillance of local pathogenic serovars. In conclusion, the data obtained from this study can contribute to the epidemiological understanding and control of leptospirosis in southern Brazil.

  18. Serovar Diversity of Pathogenic Leptospira Circulating in the French West Indies

    PubMed Central

    Bourhy, Pascale; Herrmann Storck, Cécile; Theodose, Rafaelle; Olive, Claude; Nicolas, Muriel; Hochedez, Patrick; Lamaury, Isabelle; Zinini, Farida; Brémont, Sylvie; Landier, Annie; Cassadou, Sylvie; Rosine, Jacques; Picardeau, Mathieu

    2013-01-01

    Background Leptospirosis is one of the most important neglected tropical bacterial diseases in Latin America and the Caribbean. However, very little is known about the circulating etiological agents of leptospirosis in this region. In this study, we describe the serological and molecular features of leptospires isolated from 104 leptospirosis patients in Guadeloupe (n = 85) and Martinique (n = 19) and six rats captured in Guadeloupe, between 2004 and 2012. Methods and Findings Strains were studied by serogrouping, PFGE, MLVA, and sequencing 16SrRNA and secY. DNA extracts from blood samples collected from 36 patients in Martinique were also used for molecular typing of leptospires via PCR. Phylogenetic analyses revealed thirteen different genotypes clustered into five main clades that corresponded to the species: L. interrogans, L. kirschneri, L. borgpetersenii, L. noguchi, and L. santarosai. We also identified L. kmetyi in at least two patients with acute leptospirosis. This is the first time, to our knowledge, that this species has been identified in humans. The most prevalent genotypes were associated with L. interrogans serovars Icterohaemorrhagiae and Copenhageni, L. kirschneri serovar Bogvere, and L. borgpetersenii serovar Arborea. We were unable to identify nine strains at the serovar level and comparison of genotyping results to the MLST database revealed new secY alleles. Conclusions The overall serovar distribution in the French West Indies was unique compared to the neighboring islands. Typing of leptospiral isolates also suggested the existence of previously undescribed serovars. PMID:23516654

  19. Dual nuclease activity of a Cas2 protein in CRISPR-Cas subtype I-B of Leptospira interrogans.

    PubMed

    Dixit, Bhuvan; Ghosh, Karukriti Kaushik; Fernandes, Gary; Kumar, Pankaj; Gogoi, Prerana; Kumar, Manish

    2016-04-01

    Leptospira interrogans serovar Copenhageni strain Fiocruz L1-130 carries a set of cas genes associated with CRISPR-Cas subtype I-B. Herein, we report for the first time active transcription of a set of cas genes (cas1 to cas8) of L. interrogans where cas4, cas1, cas2 and cas6, cas3, cas8, cas7, cas5 are clustered together in two independent operons. As an initial step toward comprehensive understanding of CRISPR-Cas system in spirochete, the biochemical study of one of the core Leptospira Cas2 proteins (Lep_Cas2) showed nuclease activity on both DNA and RNA in a nonspecific manner. Additionally, unlike other known Cas2 proteins, Lep_Cas2 showed metal-independent RNase activity and preferential activity on RNA over DNA. These results provide insight for understanding Cas2 diversity existing in the prokaryotic adaptive immune system.

  20. High virulence in hamsters of four dominant Leptospira serovars isolated from rats in the Philippines.

    PubMed

    Villanueva, Sharon Y A M; Saito, Mitsumasa; Tsutsumi, Yutaka; Segawa, Takaya; Baterna, Rubelia A; Chakraborty, Antara; Asoh, Tatsuma; Miyahara, Satoshi; Yanagihara, Yasutake; Cavinta, Lolita L; Gloriani, Nina G; Yoshida, Shin-ichi

    2014-02-01

    Leptospirosis is caused by pathogenic species of Leptospira. The aim of this study was to determine and characterize the pathogenicity of four dominant Leptospira isolates prevailing among rats in the Philippines. The isolates were Leptospira interrogans serovar Manilae strain K64, L. interrogans serovar Losbanos strain K37, L. interrogans serovar Ratnapura strain K5 and Leptospira borgpetersenii serovar Javanica strain K6. Pathogenicities were studied using hamsters, which reproduce severe human leptospirosis. The minimum lethal doses were 10(0) ( = 1) leptospires for K64, K37 and K5, and 10(1) leptospires for K6. Weight loss amongst the Leptospira-infected hamsters was observed from 1 day before death (K64-, K37- and K5-infected hamsters) to as much as 1 week before death for K6-infected hamsters. Similar and varied gross and microscopic lesions were observed amongst infected hamsters, even for strains belonging to the same species (i.e. L. interrogans). The most significant and common histopathological findings were congestion of the glomerulus, disarrangement of hepatic cords and erythrophagocytosis. Other findings were foamy splenic macrophages for K6, severe petechial pulmonary haemorrhage for K64, and hematuria and severe pulmonary congestion for K37. Immunostaining and culture revealed the presence of leptospires in different organs of the infected hamsters. Based on these results, Leptospira isolates from rats in the Philippines were shown to be highly virulent, causing pulmonary haemorrhage, severe hepato-renal damage and death in hamsters even at lower doses. The present findings on experimental leptospirosis support clinical data showing that patients with severe manifestations of leptospirosis, such as pulmonary haemorrhage, are increasing in the Philippines. These findings may serve as a basis to strengthen the early diagnosis and treatment of human leptospirosis.

  1. Kinetics of Leptospira interrogans Infection in Hamsters after Intradermal and Subcutaneous Challenge

    PubMed Central

    Coutinho, Mariana L.; Matsunaga, James; Wang, Long-Chieh; de la Peña Moctezuma, Alejandro; Lewis, Michael S.; Babbitt, Jane T.; Aleixo, Jose Antonio G.; Haake, David A.

    2014-01-01

    Background Leptospirosis is a zoonosis caused by highly motile, helically shaped bacteria that penetrate the skin and mucous membranes through lesions or abrasions, and rapidly disseminate throughout the body. Although the intraperitoneal route of infection is widely used to experimentally inoculate hamsters, this challenge route does not represent a natural route of infection. Methodology/Principal Findings Here we describe the kinetics of disease and infection in hamster model of leptospirosis after subcutaneous and intradermal inoculation of Leptospira interrogans serovar Copenhageni, strain Fiocruz L1-130. Histopathologic changes in and around the kidney, including glomerular and tubular damage and interstitial inflammatory changes, began on day 5, and preceded deterioration in renal function as measured by serum creatinine. Weight loss, hemoconcentration, increased absolute neutrophil counts (ANC) in the blood and hepatic dysfunction were first noted on day 6. Vascular endothelial growth factor, a serum marker of sepsis severity, became elevated during the later stages of infection. The burden of infection, as measured by quantitative PCR, was highest in the kidney and peaked on day 5 after intradermal challenge and on day 6 after subcutaneous challenge. Compared to subcutaneous challenge, intradermal challenge resulted in a lower burden of infection in both the kidney and liver on day 6, lower ANC and less weight loss on day 7. Conclusions/Significance The intradermal and subcutaneous challenge routes result in significant differences in the kinetics of dissemination and disease after challenge with L. interrogans serovar Copenhageni strain Fiocruz L1-130 at an experimental dose of 2×106 leptospires. These results provide new information regarding infection kinetics in the hamster model of leptospirosis. PMID:25411782

  2. Leptospira interrogans in Rodents from Cape Verde.

    PubMed

    Plata-Luis, Josué; Foronda, Pilar; Martín-Alonso, Aaron; Feliu, Carlos; Alves, Joana; Gil, Horacio; Valladares, Basilio

    2016-11-01

    Leptospirosis is an important worldwide zoonotic disease that can infect both animals and humans. In most cases, leptospirosis is a nonspecific self-limiting illness, but some patients can develop a severe form with a high mortality. This study was carried out in Santiago Island, Cape Verde, in 2012-2013. A total of 62 wild rodents (Rattus rattus and Mus domesticus) were analyzed. The lipL32 gene, present only in pathogenic Leptospira spp., was amplified by PCR, and 16 samples were positive (25.8%). In both rodent species, Leptospira interrogans was identified. The results show the presence of pathogenic Leptospira in the three localities analyzed in Santiago. The presence of L. interrogans demonstrates a serious health risk for the population, since this species has been associated with the most severe form of leptospirosis, the Weil's disease in humans, a severe infection with jaundice, renal failure, and hemorrhage.

  3. A Spatio-Temporal Enhancement Method for medium resolution LAI (STEM-LAI)

    NASA Astrophysics Data System (ADS)

    Houborg, Rasmus; McCabe, Matthew F.; Gao, Feng

    2016-05-01

    Satellite remote sensing has been used successfully to map leaf area index (LAI) across landscapes, but advances are still needed to exploit multi-scale data streams for producing LAI at both high spatial and temporal resolution. A multi-scale Spatio-Temporal Enhancement Method for medium resolution LAI (STEM-LAI) has been developed to generate 4-day time-series of Landsat-scale LAI from existing medium resolution LAI products. STEM-LAI has been designed to meet the demands of applications requiring frequent and spatially explicit information, such as effectively resolving rapidly evolving vegetation dynamics at sub-field (30 m) scales. In this study, STEM-LAI is applied to Moderate Resolution Imaging Spectroradiometer (MODIS) based LAI data and utilizes a reference-based regression tree approach for producing MODIS-consistent, but Landsat-based, LAI. The Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM) is used to interpolate the downscaled LAI between Landsat acquisition dates, providing a high spatial and temporal resolution improvement over existing LAI products. STARFM predicts high resolution LAI by blending MODIS and Landsat based information from a common acquisition date, with MODIS data from a prediction date. To demonstrate its capacity to reproduce fine-scale spatial features observed in actual Landsat LAI, the STEM-LAI approach is tested over an agricultural region in Nebraska. The implementation of a 250 m resolution LAI product, derived from MODIS 1 km data and using a scale consistent approach based on the Normalized Difference Vegetation Index (NDVI), is found to significantly improve accuracies of spatial pattern prediction, with the coefficient of efficiency (E) ranging from 0.77-0.94 compared to 0.01-0.85 when using 1 km LAI inputs alone. Comparisons against an 11-year record of in-situ measured LAI over maize and soybean highlight the utility of STEM-LAI in reproducing observed LAI dynamics (both characterized by r2 = 0.86) over a

  4. Molecular characterization by LSSP-PCR and DNA sequencing of a pathogenic isolate of Leptospira interrogans from Brazil.

    PubMed

    Cosate, M R V; Barouni, A S; Moreira, E C; Veloso, I F; Gomes, M T R; Salas, C E

    2012-09-01

    We report the initial characterization of a leptospiral isolate, Leptospira interrogans, serogroup Sejroe, serovar Hardjo, genotype Hardjoprajitno, strain Norma, and its relatedness with L. interrogans, serogroup Sejroe, serovar Hardjo, genotype Hardjoprajitno, strain Hardjo and Leptospira borgpetersenii, serogroup Sejroe, serovar Hardjo, genotype Hardjobovis, strain Sponselee. The Norma strain singled out during a leptospirosis outbreak in cattle immunized with antigens from the reference strain Hardjoprajitno (OMS). By applying a microscopic agglutination serological test (MAT) to cattle (n = 2966) with symptoms of leptospirosis between 2003 and 2007, more than 50% of sera were found positive for one of the following serotypes: Hardjoprajitno (31-21%), Hardjo Norma (46-40%), Hardjo hardjobovis (18-10%), Mini (8-4%) and Wolffi (7-4%). In immunization trials using six isolates plus Norma isolate, the remission of MAT in these isolates was observed following 6 months of the initial vaccination. To provide molecular ground for the high MAT Norma frequency found in these isolates, a DNA polymorphic analysis was conducted by comparing the Norma isolate with reference strains Hardjoprajitno and Sponselee. The polymorphic analysis in secY showed five base changes in Norma relative to Hardjoprajitno strain, corresponding to 98% identity, while Sponselee displayed 49 polymorphic sites relative to the Hardjoprajitno strain, representing 80% identity. The alignment of secY translated sequences shows no differences between Hardjoprajitno and Norma, and eight polymorphisms between genotype hardjoprajttno and strain Sponselee. Three-dimensional modelling located these variations within the loop region connecting helices 7 and 8 from secY which is less conserved. DNA sequencing of 23S ribosomal conserved fragment revealed a single polymorphism between Hardjoprajitno and Norma, and 13 polymorphisms between strains Sponselee, Hardjoprajitno and Norma. The differences between

  5. Isolation and characterization of Leptospira interrogans from pigs slaughtered in São Paulo State, Brazil

    PubMed Central

    Miraglia, Fabiana; Moreno, Andréa Mike; Gomes, Cleise Ribeiro; Paixão, Renata; Liuson, Esequiel; Morais, Zenaide Maria; Maiorka, Paulo; Seixas, Fabiana Kömmling; Dellagostin, Odir Antonio; Vasconcellos, Silvio Arruda

    2008-01-01

    With the aim of isolating Leptospira spp., blood serum, kidney, liver and genital tract of 137 female swine (40 sows and 97 gilts) and also urine samples from 22 sows were collected in a slaughterhouse in the State of São Paulo, from April 2003 to August 2004. Four isolates were obtained from animals that presented microagglutination test (MAT) titers ≥ 100 for the serovar Pomona and one was obtained from an animal negative by MAT in which Leptospira was isolated from the liver and reproductive tract. The presence of leptospiral DNA was investigated by PCR, and positive results were found in kidneys of 11 females, liver of two, genital tract of two and urine of one of them. Nephrosis, interstitial multifocal nephritis, moderate to severe changing, hyalines cylinders and hemorrhagic focuses, hepatic and uterine horns congestion were histological lesions observed in higher frequency in animals positive for leptospira. The silver impregnation (Warthin Starry) confirmed the presence of spirochetes in renal tubules of four females with positive leptospira cultures from kidneys. The serogroup of the five isolates was identified as Pomona by cross agglutination with reference polyclonal antibodies. Molecular characterization of the isolates was carried out by variable-number tandem-repeats analysis. All the isolates revealed a pattern distinct from the L. interrogans Pomona type strain, but identical to a previously identified pattern from strains isolated in Argentina belonging to serovar Pomona. PMID:24031254

  6. Comparison of Bacterial Burden and Cytokine Gene Expression in Golden Hamsters in Early Phase of Infection with Two Different Strains of Leptospira interrogans.

    PubMed

    Fujita, Rie; Koizumi, Nobuo; Sugiyama, Hiromu; Tomizawa, Rina; Sato, Ryoichi; Ohnishi, Makoto

    2015-01-01

    Leptospirosis, a zoonotic infection with worldwide prevalence, is caused by pathogenic spirochaetes of Leptospira spp., and exhibits an extremely broad clinical spectrum in human patients. Although previous studies indicated that specific serovars or genotypes of Leptospira spp. were associated with severe leptospirosis or its outbreak, the mechanism underlying the difference in virulence of the various Leptospira serotypes or genotypes remains unclear. The present study addresses this question by measuring and comparing bacterial burden and cytokine gene expression in hamsters infected with strains of two L. interrogans serovars Manilae (highly virulent) and Hebdomadis (less virulent). The histopathology of kidney, liver, and lung tissues was also investigated in infected hamsters. A significantly higher bacterial burden was observed in liver tissues of hamsters infected with serovar Manilae than those infected with serovar Hebdomadis (p < 0.01). The average copy number of the leptospiral genome was 1,302 and 20,559 in blood and liver, respectively, of hamsters infected with serovar Manilae and 1,340 and 4,896, respectively, in hamsters infected with serovar Hebdomadis. The expression levels of mip1alpha in blood; tgfbeta, il1beta, mip1alpha, il10, tnfalpha and cox2 in liver; and tgfbeta, il6, tnfalpha and cox2 in lung tissue were significantly higher in hamsters infected with serovar Manilae than those infected with serovar Hebdomadis (p < 0.05). In addition, infection with serovar Manilae resulted in a significantly larger number of hamsters with tnfalpha upregulation (p = 0.04). Severe distortion of tubular cell arrangement and disruption of renal tubules in kidney tissues and hemorrhage in lung tissues were observed in Manilae-infected hamsters. These results demonstrate that serovar Manilae multiplied more efficiently in liver tissues and induced significantly higher expression of genes encoding pro- and anti-inflammatory cytokines than serovar Hebdomadis

  7. Detecting signals of chronic shedding to explain pathogen persistence: Leptospira interrogans in California sea lions.

    PubMed

    Buhnerkempe, Michael G; Prager, Katherine C; Strelioff, Christopher C; Greig, Denise J; Laake, Jeff L; Melin, Sharon R; DeLong, Robert L; Gulland, Frances M D; Lloyd-Smith, James O

    2017-05-01

    Identifying mechanisms driving pathogen persistence is a vital component of wildlife disease ecology and control. Asymptomatic, chronically infected individuals are an oft-cited potential reservoir of infection, but demonstrations of the importance of chronic shedding to pathogen persistence at the population-level remain scarce. Studying chronic shedding using commonly collected disease data is hampered by numerous challenges, including short-term surveillance that focuses on single epidemics and acutely ill individuals, the subtle dynamical influence of chronic shedding relative to more obvious epidemic drivers, and poor ability to differentiate between the effects of population prevalence of chronic shedding vs. intensity and duration of chronic shedding in individuals. We use chronic shedding of Leptospira interrogans serovar Pomona in California sea lions (Zalophus californianus) as a case study to illustrate how these challenges can be addressed. Using leptospirosis-induced strands as a measure of disease incidence, we fit models with and without chronic shedding, and with different seasonal drivers, to determine the time-scale over which chronic shedding is detectable and the interactions between chronic shedding and seasonal drivers needed to explain persistence and outbreak patterns. Chronic shedding can enable persistence of L. interrogans within the sea lion population. However, the importance of chronic shedding was only apparent when surveillance data included at least two outbreaks and the intervening inter-epidemic trough during which fadeout of transmission was most likely. Seasonal transmission, as opposed to seasonal recruitment of susceptibles, was the dominant driver of seasonality in this system, and both seasonal factors had limited impact on long-term pathogen persistence. We show that the temporal extent of surveillance data can have a dramatic impact on inferences about population processes, where the failure to identify both short- and

  8. Estimating Leaf Area Index (LAI) in Vineyards Using the PocketLAI Smart-App.

    PubMed

    Orlando, Francesca; Movedi, Ermes; Coduto, Davide; Parisi, Simone; Brancadoro, Lucio; Pagani, Valentina; Guarneri, Tommaso; Confalonieri, Roberto

    2016-11-26

    Estimating leaf area index (LAI) of Vitis vinifera using indirect methods involves some critical issues, related to its discontinuous and non-homogeneous canopy. This study evaluates the smart app PocketLAI and hemispherical photography in vineyards against destructive LAI measurements. Data were collected during six surveys in an experimental site characterized by a high level of heterogeneity among plants, allowing us to explore a wide range of LAI values. During the last survey, the possibility to combine remote sensing data and in-situ PocketLAI estimates (smart scouting) was evaluated. Results showed a good agreement between PocketLAI data and direct measurements, especially for LAI ranging from 0.13 to 1.41 (R² = 0.94, RRMSE = 17.27%), whereas the accuracy decreased when an outlying value (vineyard LAI = 2.84) was included (R² = 0.77, RRMSE = 43.00%), due to the saturation effect in case of very dense canopies arising from lack of green pruning. The hemispherical photography showed very high values of R², even in presence of the outlying value (R² = 0.94), although it showed a marked and quite constant overestimation error (RRMSE = 99.46%), suggesting the need to introduce a correction factor specific for vineyards. During the smart scouting, PocketLAI showed its reliability to monitor the spatial-temporal variability of vine vigor in cordon-trained systems, and showed a potential for a wide range of applications, also in combination with remote sensing.

  9. Isolation of Leptospira interrogans Hardjoprajitno from vaginal fluid of a clinically healthy ewe suggests potential for venereal transmission.

    PubMed

    Director, A; Penna, B; Hamond, C; Loureiro, A P; Martins, G; Medeiros, M A; Lilenbaum, W

    2014-09-01

    A total of 15 adult ewes from one flock known to be seroreactive for leptospirosis was studied. Urine and vaginal fluid were collected from each animal to test for the presence of leptospires using bacterial culture and conventional PCR methods. One pure culture of Leptospira sp. was obtained from the vaginal fluid sample of a non-pregnant ewe. The isolate was characterized by DNA sequencing of the rrs and secY genes, variable-number of tandem-repeats (VNTR) analysis and serogrouping, and the isolate was typed as Leptospira interrogans serogroup Sejroe serovar Hardjo type Hardjoprajitno. This report indicates the presence of viable Leptospira in the vaginal fluid of a ewe, suggesting the potential for venereal transmission of leptospires in sheep.

  10. Stray dogs as reservoirs of the zoonotic agents Leptospira interrogans, Trypanosoma cruzi, and Aspergillus spp. in an urban area of Chiapas in southern Mexico.

    PubMed

    Jimenez-Coello, Matilde; Ortega-Pacheco, Antonio; Guzman-Marin, Eugenia; Guiris-Andrade, Dario M; Martinez-Figueroa, Laura; Acosta-Viana, Karla Y

    2010-03-01

    This investigation determined the presence and prevalence of the zoonotic agents Leptospira interrogans, Trypanosoma cruzi, and Aspergillus spp. in the stray dog population (a total of 224 stray dogs) in an urban area of Southern Mexico. Blood serum samples were taken from all dogs, and root hair samples were taken from dogs with skin lesions and partial alopecia. IgG antibodies for L. interrogans from 10 serovars were detected using the microscopic agglutination test. Immunofluorescence antibody test and Western blot assay were used for serologic diagnosis of T. cruzi. The Sabouraud medium was used to isolate Aspergillus spp. Prevalence of L. interrogans was 4.9%, which was determined by identifying only serovars Pyrogenes, which accounted for 3.6%, and Tarassovi, which constituted 1.3%, with titers from 1:100 to 1:800. Additionally, T. cruzi antibodies were detected in 4.5% of the dogs. Skin lesions were found in 43% of the dogs (98/224), and 35 cultures were positive for Aspergillus spp. (35.7%, p < 0.05, 95% confidence interval 2.45-3.67), identified as A. niger (82.8%), A. flavus (14.3%), and A. terreus (2.9%). This study demonstrates the presence of certain zoonotic agents (bacteria, protozoa, and fungi) in stray dogs living within the studied area. Dogs play an important role in the transmission of diseases that are potentially harmful to humans. Although the prevalence of canine leptospirosis and trypanosomiasis is not high in Southern Mexico compared with other tropical regions of Mexico, the presence of these zoonotic agents in the stray dog population demonstrates that the stray dog population in this region is a significant reservoir and potential source of infection in humans. Special care should be taken when handling stray dogs that exhibit skin lesions with partial alopecia, since a pathological Aspergillus sp. fungus may be present.

  11. Lai Products and Validation For Hydrological Processes

    NASA Astrophysics Data System (ADS)

    Baret, Frédéric; Combal, Bruno; Moulin, Sophie; Bacour, Cédric; Weiss, Marie; Garrigues, Sébastien

    Leaf area index (LAI) is a very important variable required in many hydrological processes. It controls evapotranspiration in several ways, rain interception and run- off. However, because LAI may change rapidly with space and time, estimates derived from remote sensing data could be used as input to spatially distributed hydrological models running at a range of scales. The derivation of LAI from remote sensing data is not straightforward since several factors may confound LAI effect on reflectance. We propose to use radiative transfer model inversion to estimate LAI from top of canopy reflectance measurements. Several inversion approaches are compared, with emphasis put on the regularisation of the inverse process by introducing prior information on the variables. Applications of this approach is made over several agricultural data sets at high spatial resolution (few 10th meters) thanks to hyperspectral (CASI, HYMAP) and BRDF (POLDER) airborne sensors. It includes the ReSeDA experiment on the Alpilles site in 1997 based on POLDER sensor, the Blue Earth experiment based on CASI in 1997, the DAISEX experiment in 1999 with POLDER and HYMAP and the Laon experiment based on CASI data in 2000 and 2001. The limitations of these approaches are discussed, with due attention on the way to derive prior information, inverse techniques, uncertainties on measurements and models, and scaling effects.

  12. First Observation of Leptospira interrogans in the Lungs of Rattus norvegicus

    PubMed Central

    Belli, Patrick; Artois, Marc; Djelouadji, Zoheira

    2016-01-01

    We report the first two cases of pulmonary presence of leptospires in apparently healthy rats captured in a city park in Lyon (France). Only renal carriage of Leptospira has been described in the literature. Blood serology was performed in parallel with molecular and histological analyses of the kidney and lung samples. We isolated leptospires from the kidneys of two out of three seropositive wild rats. These results were confirmed by specific detection of pathogenic Leptospira by real-time PCR. Moreover, Leptospira DNA was detected in lung tissues. Immunohistochemistry and Warthin-Starry staining revealed that leptospires were present on the surface of the ciliated epithelium of the bronchi. Using PCR of the rrs (16S) gene and Multispacer Sequence Typing, DNA extracts of the kidney and lung were identified as belonging to Leptospira interrogans serovar Icterohaemorrhagiae “CHU Réunion.” This first observation of the presence Leptospira in the lung with simultaneous renal carriage will require further study in future on several target organs to gain a better understanding of the Leptospira infection in wild rat. PMID:27800495

  13. Estimating Leaf Area Index (LAI) in Vineyards Using the PocketLAI Smart-App

    PubMed Central

    Orlando, Francesca; Movedi, Ermes; Coduto, Davide; Parisi, Simone; Brancadoro, Lucio; Pagani, Valentina; Guarneri, Tommaso; Confalonieri, Roberto

    2016-01-01

    Estimating leaf area index (LAI) of Vitis vinifera using indirect methods involves some critical issues, related to its discontinuous and non-homogeneous canopy. This study evaluates the smart app PocketLAI and hemispherical photography in vineyards against destructive LAI measurements. Data were collected during six surveys in an experimental site characterized by a high level of heterogeneity among plants, allowing us to explore a wide range of LAI values. During the last survey, the possibility to combine remote sensing data and in-situ PocketLAI estimates (smart scouting) was evaluated. Results showed a good agreement between PocketLAI data and direct measurements, especially for LAI ranging from 0.13 to 1.41 (R2 = 0.94, RRMSE = 17.27%), whereas the accuracy decreased when an outlying value (vineyard LAI = 2.84) was included (R2 = 0.77, RRMSE = 43.00%), due to the saturation effect in case of very dense canopies arising from lack of green pruning. The hemispherical photography showed very high values of R2, even in presence of the outlying value (R2 = 0.94), although it showed a marked and quite constant overestimation error (RRMSE = 99.46%), suggesting the need to introduce a correction factor specific for vineyards. During the smart scouting, PocketLAI showed its reliability to monitor the spatial-temporal variability of vine vigor in cordon-trained systems, and showed a potential for a wide range of applications, also in combination with remote sensing. PMID:27898028

  14. Asymptomatic and chronic carriage of Leptospira interrogans serovar Pomona in California sea lions (Zalophus californianus)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since 1970, periodic outbreaks of leptospirosis, caused by pathogenic spirochetes in the genus Leptospira, have caused morbidity and mortality of California sea lions (Zalophus californianus) along the Pacific coast of North America. Yearly seasonal epizootics of varying magnitude occur between the ...

  15. Severe Leptospira interrogans serovar Icterohaemorrhagiae infection with hepato-renal-pulmonary involvement treated with corticosteroids

    PubMed Central

    Schulze, Marco H; Raschel, Heribert; Langen, Heinz-Jakob; Stich, August; Tappe, Dennis

    2014-01-01

    Key Clinical Message The traditional concept of immediate antibiotic treatment in suspected leptospirosis seems to be especially important for patients up to day 4 of clinical illness. As immune mechanisms probably play a crucial role in advanced leptospirosis with presumed pulmonary hemorrhages, patients might benefit from corticosteroids or other immunosuppressive agents beside antibiotics. PMID:25614810

  16. Post-translational Modification of LipL32 during Leptospira interrogans Infection

    PubMed Central

    Witchell, Timothy D.; Eshghi, Azad; Nally, Jarlath E.; Hof, Rebecca; Boulanger, Martin J.; Wunder, Elsio A.; Ko, Albert I.; Haake, David A.; Cameron, Caroline E.

    2014-01-01

    Background Leptospirosis, a re-emerging disease of global importance caused by pathogenic Leptospira spp., is considered the world's most widespread zoonotic disease. Rats serve as asymptomatic carriers of pathogenic Leptospira and are critical for disease spread. In such reservoir hosts, leptospires colonize the kidney, are shed in the urine, persist in fresh water and gain access to a new mammalian host through breaches in the skin. Methodology/Principal Findings Previous studies have provided evidence for post-translational modification (PTM) of leptospiral proteins. In the current study, we used proteomic analyses to determine the presence of PTMs on the highly abundant leptospiral protein, LipL32, from rat urine-isolated L. interrogans serovar Copenhageni compared to in vitro-grown organisms. We observed either acetylation or tri-methylation of lysine residues within multiple LipL32 peptides, including peptides corresponding to regions of LipL32 previously identified as epitopes. Intriguingly, the PTMs were unique to the LipL32 peptides originating from in vivo relative to in vitro grown leptospires. The identity of each modified lysine residue was confirmed by fragmentation pattern analysis of the peptide mass spectra. A synthetic peptide containing an identified tri-methylated lysine, which corresponds to a previously identified LipL32 epitope, demonstrated significantly reduced immunoreactivity with serum collected from leptospirosis patients compared to the peptide version lacking the tri-methylation. Further, a subset of the identified PTMs are in close proximity to the established calcium-binding and putative collagen-binding sites that have been identified within LipL32. Conclusions/Significance The exclusive detection of PTMs on lysine residues within LipL32 from in vivo-isolated L. interrogans implies that infection-generated modification of leptospiral proteins may have a biologically relevant function during the course of infection. Although

  17. Isolation and molecular characterization of Leptospira borgpetersenii serovar Hardjo strain Hardjobovis in the urine of naturally infected cattle in Brazil.

    PubMed

    Chideroli, R T; Pereira, U P; Gonçalves, D D; Nakamura, A Y; Alfieri, A A; Alfieri, A F; Freitas, J C

    2016-02-19

    Most epidemiologic studies on bovine leptospirosis are based on serological tests that use antibodies against several serotypes, including the serovar Hardjo, which is widespread and considered to be the most adapted to bovine hosts. However, using only serological studies is not sufficient to identify and distinguish species of leptospires. The aim of this study was report the first isolation in Brazil of two strains serovar Hardjo obtained in urine samples from naturally infected cows in a small Brazilian dairy herd and find the genetic species and consequently the type strain Hardjobovis by molecular characterization. Fifteen dairy cows with a history of reproductive failure, such as abortion and infertility, were selected. Urine samples obtained from each animal were immediately seeded in tubes containing Ellinghausen-McCullough-Johnson-Harris culture medium. The identification of the isolates was performed by Multilocus variable-number tandem-repeat analysis (MLVA) technique and phylogenetic analysis of partial sequence of gene sec Y. From the 15 urine samples evaluated, two Leptospira were found and identified as the Londrina 49 and Londrina 54 strains. The MLVA profiles and sequencing of gene sec Y characterized the isolates as L. borgpetersenii serovar Hardjo strain Hadjobovis because it has different genetic pattern of Leptospira interrogans serovar Hardjo strain Hardjoprajitno. Therefore, more studies are needed including isolation and molecular characterization from regional strains to obtain a better knowledge about epidemiology of serovar Hardjo in bovine which may assist in future strategies of prevention and control of bovine leptospirosis.

  18. New wildlife hosts of Leptospira interrogans in Campeche, Mexico.

    PubMed

    Espinosa-Martínez, Deborah V; Sánchez-Montes, Daniel Sokani; León-Paniagua, Livia; Ríos-Muñoz, César A; Berzunza-Cruz, Miriam; Becker, Ingeborg

    2015-01-01

    Leptospira interrogans has been identified to cause leptospirosis, a widespread zoonotic disease that has been identified in domestic and wild animals. This work analyzed kidneys from two species of wild rodents from the state of Campeche, Mexico. Analyses were made by PCR using specific primers for detection of Leptospira interrogans DNA. The rodent species that tested positive were Heteromys gaumeri and Ototylomys phyllotis, both of which are new hosts for the bacteria in Southeastern Mexico. These records provide new insights into the disease's transmission that should be studied carefully in order to identify other potential host species, including humans, which are at risk of becoming infected if they are in contact with infected wildlife.

  19. NEW WILDLIFE HOSTS OF Leptospira interrogans IN CAMPECHE, MEXICO

    PubMed Central

    ESPINOSA-MARTÍNEZ, Deborah V.; SÁNCHEZ-MONTES, Daniel Sokani; LEÓN-PANIAGUA, Livia; RÍOS-MUÑOZ, César A.; BERZUNZA-CRUZ, Miriam; BECKER, Ingeborg

    2015-01-01

    Leptospira interrogans has been identified to cause leptospirosis, a widespread zoonotic disease that has been identified in domestic and wild animals. This work analyzed kidneys from two species of wild rodents from the state of Campeche, Mexico. Analyses were made by PCR using specific primers for detection of Leptospira interrogans DNA. The rodent species that tested positive were Heteromys gaumeri and Ototylomys phyllotis, both of which are new hosts for the bacteria in Southeastern Mexico. These records provide new insights into the disease’s transmission that should be studied carefully in order to identify other potential host species, including humans, which are at risk of becoming infected if they are in contact with infected wildlife. PMID:25923901

  20. Seasonal LAI in slash pine estimated with LANDSAT TM

    NASA Technical Reports Server (NTRS)

    Curran, Paul J.; Dungan, Jennifer L.; Gholz, Henry L.

    1990-01-01

    The leaf area index (LAI, total area of leaves per unit area of ground) of most forest canopies varies throughout the year, yet for logistical reasons it is difficult to estimate anything more detailed than a seasonal maximum LAI. To determine if remotely sensed data can be used to estimate LAI seasonally, field measurements of LAI were compared to normalized difference vegetation index (NDVI) values derived using LANDSAT Thematic Mapper (TM) data, for 16 fertilized and control slash pine plots on 3 dates. Linear relationships existed between NDVI and LAI with R(sup 2) values of 0.35, 0.75, and 0.86 for February 1988, September 1988, and March, 1989, respectively. This is the first reported study in which NDVI is related to forest LAI recorded during the month of sensor overpass. Predictive relationships based on data from eight of the plots were used to estimate the LAI of the other eight plots with a root-mean-square error of 0.74 LAI, which is 15.6 percent of the mean LAI. This demonstrates the potential use of LANDSAT TM data for studying seasonal dynamics in forest canopies.

  1. Seasonal LAI in slash pine estimated with Landsat TM

    NASA Technical Reports Server (NTRS)

    Curran, Paul J.; Dungan, Jennifer L.; Gholz, Henry L.

    1992-01-01

    The leaf area index (LAI, total area of leaves per unit area of ground) of most forest canopies varies throughout the year, yet for logistical reasons it is difficult to estimate anything more detailed than a seasonal maximum LAI. To determine if remotely sensed data can be used to estimate LAI seasonally, field measurements of LAI were compared to normalized difference vegetation index (NDVI) values derived using Lnandsat Thematic Mapper (TM) data, for 16 fertilized and control slash pine plots on 3 dates. Linear relationships existed between NDVI and LAI with R (sup 2) values of 0.35, 0.75, and 0.86 for February 1988, September 1988, and March, 1989, respectively. This is the first reported study in which NDVI is related to forest LAI recorded during the month of sensor overpass. Predictive relationships based on data from eight of the plots were used to estimate the LAI of the other eight plots with a root-mean-square error of 0.74 LAI, which is 15.6 percent of the mean LAI. This demonstrates the potential use of Landsat TM data for studying seasonal dynamics in forest canopies.

  2. Distribution of Leptospira interrogans by Multispacer Sequence Typing in Urban Norway Rats (Rattus norvegicus): A Survey in France in 2011-2013

    PubMed Central

    Bicout, Dominique J.; Kodjo, Angeli; Artois, Marc; Djelouadji, Zoheira

    2015-01-01

    Background Urban leptospirosis has increasingly been reported in both developing and developed countries. The control of the disease is limited because our understanding of basic aspects of the epidemiology, including the transmission routes of leptospires among rat populations, remains incomplete. Through the ability to distinguish among Leptospira strains in rats, multispacer sequence typing (MST) could provide a modern understanding of Leptospira epidemiology; however, to our knowledge, the distribution of Leptospira strains among urban rat colonies has not been investigated using MST. Aims and Methodology The objective of this study was to identify the Leptospira strains present in rats (Rattus norvegicus) in Lyon (France) using MST and to characterize their spatial distribution. Kidneys and urine were collected from rats trapped live in seven locations in the city and in one suburban location. Each location was considered to represent a rat colony. Bacterial cultures and quantitative polymerase chain reaction (qPCR) assays were performed, and the L. interrogans DNA identified was then genotyped using MST. The distributions of Leptospira strains were spatially described. Key Results Among 84 wild rats, MST profiles were obtained in 35 of 37 rats that had a positive result for L. interrogans by bacterial culture and/or qPCR analyses. All of the MST profiles were related to reference strains previously isolated from human patients that belong to the serogroup Icterohaemorrhagiae and the serovars [strain(s)] Copenhageni [Wijinberg or M20] (n = 26), Icterohaemorrhagiae [CHU Réunion] (n = 7), Icterohaemorrhagiae [R1] (n = 1) and Copenhageni [Shibaura 9] (n = 1). Each colony was infected with leptospires having the same MST profile. Major Conclusions This study demonstrated that MST could be used for the purpose of field studies, either on culture isolates or on DNA extracted from kidneys and urine, to distinguish among L. interrogans isolates in rats. MST could

  3. The Effect of Lidar Point Density on LAI Estimation

    NASA Astrophysics Data System (ADS)

    Cawse-Nicholson, K.; van Aardt, J. A.; Romanczyk, P.; Kelbe, D.; Bandyopadhyay, M.; Yao, W.; Krause, K.; Kampe, T. U.

    2013-12-01

    Leaf Area Index (LAI) is an important measure of forest health, biomass and carbon exchange, and is most commonly defined as the ratio of the leaf area to ground area. LAI is understood over large spatial scales and describes leaf properties over an entire forest, thus airborne imagery is ideal for capturing such data. Spectral metrics such as the normalized difference vegetation index (NDVI) have been used in the past for LAI estimation, but these metrics may saturate for high LAI values. Light detection and ranging (lidar) is an active remote sensing technology that emits light (most often at the wavelength 1064nm) and uses the return time to calculate the distance to intercepted objects. This yields information on three-dimensional structure and shape, which has been shown in recent studies to yield more accurate LAI estimates than NDVI. However, although lidar is a promising alternative for LAI estimation, minimum acquisition parameters (e.g. point density) required for accurate LAI retrieval are not yet well known. The objective of this study was to determine the minimum number of points per square meter that are required to describe the LAI measurements taken in-field. As part of a larger data collect, discrete lidar data were acquired by Kucera International Inc. over the Hemlock-Canadice State Forest, NY, USA in September 2012. The Leica ALS60 obtained point density of 12 points per square meter and effective ground sampling distance (GSD) of 0.15m. Up to three returns with intensities were recorded per pulse. As part of the same experiment, an AccuPAR LP-80 was used to collect LAI estimates at 25 sites on the ground. Sites were spaced approximately 80m apart and nine measurements were made in a grid pattern within a 20 x 20m site. Dominant species include Hemlock, Beech, Sugar Maple and Oak. This study has the benefit of very high-density data, which will enable a detailed map of intra-forest LAI. Understanding LAI at fine scales may be particularly useful

  4. Three Different Methods of Estimating LAI in a Small Watershed

    NASA Astrophysics Data System (ADS)

    Speckman, H. N.; Ewers, B. E.; Beverly, D.

    2015-12-01

    Leaf area index (LAI) is a critical input of models that improve predictive understanding of ecology, hydrology, and climate change. Multiple techniques exist to quantify LAI, most of which are labor intensive, and all often fail to converge on similar estimates. . Recent large-scale bark beetle induced mortality greatly altered LAI, which is now dominated by younger and more metabolically active trees compared to the pre-beetle forest. Tree mortality increases error in optical LAI estimates due to the lack of differentiation between live and dead branches in dense canopy. Our study aims to quantify LAI using three different LAI methods, and then to compare the techniques to each other and topographic drivers to develop an effective predictive model of LAI. This study focuses on quantifying LAI within a small (~120 ha) beetle infested watershed in Wyoming's Snowy Range Mountains. The first technique estimated LAI using in-situ hemispherical canopy photographs that were then analyzed with Hemisfer software. The second LAI estimation technique was use of the Kaufmann 1982 allometrerics from forest inventories conducted throughout the watershed, accounting for stand basal area, species composition, and the extent of bark beetle driven mortality. The final technique used airborne light detection and ranging (LIDAR) first DMS returns, which were used to estimating canopy heights and crown area. LIDAR final returns provided topographical information and were then ground-truthed during forest inventories. Once data was collected, a fractural analysis was conducted comparing the three methods. Species composition was driven by slope position and elevation Ultimately the three different techniques provided very different estimations of LAI, but each had their advantage: estimates from hemisphere photos were well correlated with SWE and snow depth measurements, forest inventories provided insight into stand health and composition, and LIDAR were able to quickly and

  5. Methylation and in vivo expression of the surface-exposed Leptospira interrogans outer-membrane protein OmpL32

    PubMed Central

    Eshghi, Azad; Pinne, Marija; Haake, David A.; Zuerner, Richard L.; Frank, Ami

    2012-01-01

    Recent studies have revealed that bacterial protein methylation is a widespread post-translational modification that is required for virulence in selected pathogenic bacteria. In particular, altered methylation of outer-membrane proteins has been shown to modulate the effectiveness of the host immune response. In this study, 2D gel electrophoresis combined with MALDI-TOF MS identified a Leptospira interrogans serovar Copenhageni strain Fiocruz L1-130 protein, corresponding to ORF LIC11848, which undergoes extensive and differential methylation of glutamic acid residues. Immunofluorescence microscopy implicated LIC11848 as a surface-exposed outer-membrane protein, prompting the designation OmpL32. Indirect immunofluorescence microscopy of golden Syrian hamster liver and kidney sections revealed expression of OmpL32 during colonization of these organs. Identification of methylated surface-exposed outer-membrane proteins, such as OmpL32, provides a foundation for delineating the role of this post-translational modification in leptospiral virulence. PMID:22174381

  6. Occurrence of antibodies anti -Toxoplasma gondii, Neospora caninum and Leptospira interrogans in a captive deer herd in Southern Brazil.

    PubMed

    Zimpel, Cristina Kraemer; Grazziotin, Ana Laura; de Barros Filho, Ivan Roque; Guimaraes, Ana Marcia de Sa; dos Santos, Leonilda Correia; de Moraes, Wanderlei; Cubas, Zalmir Silvino; de Oliveira, Marcos Jose; Pituco, Edviges Maristela; Lara, Maria do Carmo Custódio de Souza Hunold; Villalobos, Eliana Monteforte Cassaro; Silva, Lília Marcia Paulin; Cunha, Elenice Maria Sequetin; Castro, Vanessa; Biondo, Alexander Welker

    2015-01-01

    A large number of Brazilian zoos keep many endangered species of deer, however, very few disease surveillance studies have been conducted among captive cervids. Blood samples from 32 Brazilian deer (Blastocerus dichotomus, Mazama nana and Mazama americana) kept in captivity at Bela Vista Biological Sanctuary (Foz do Iguaçu, Brazil) were investigated for 10 ruminant pathogens, with the aims of monitoring deer health status and evaluating any potential zoonotic risk. Deer serum samples were tested for Brucella abortus, Leptospira (23 serovars), Toxoplasma gondii, Neospora caninum, bovine viral diarrhea virus, infectious bovine rhinotracheitis virus, foot-and-mouth disease virus, western equine encephalitis virus, eastern equine encephalitis virus and Venezuelan equine encephalitis virus. Antibodies against T. gondii (15.6%), N. caninum (6.2%) and L. interrogans serogroup Serjoe (3.1%) were detected. The serological results for all other infectious agents were negative. The deer were considered to be clinically healthy and asymptomatic regarding any disease. Compared with studies on free-ranging deer, the prevalences of the same agents tested among the captive deer kept at the Sanctuary were lower, thus indicating good sanitary conditions and high-quality management practices at the zoo.

  7. 75 FR 8081 - Patrick J. Lais: Debarment Order

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-23

    ... a.m. and 4 p.m., Monday through Friday. Dated: January 26, 2010. Brenda Holman, Acting Director... HUMAN SERVICES Food and Drug Administration Patrick J. Lais: Debarment Order AGENCY: Food and Drug... the Federal Food, Drug, and Cosmetic Act (the act) permanently debarring Patrick J. Lais...

  8. Brown and green LAI mapping through spectral indices

    NASA Astrophysics Data System (ADS)

    Delegido, Jesús; Verrelst, Jochem; Rivera, Juan P.; Ruiz-Verdú, Antonio; Moreno, José

    2015-03-01

    When crops senescence, leaves remain until they fall off or are harvested. Hence, leaf area index (LAI) stays high even when chlorophyll content degrades to zero. Current LAI approaches from remote sensing techniques are not optimized for estimating LAI of senescent vegetation. In this paper a two-step approach has been proposed to realize simultaneous LAI mapping over green and senescent croplands. The first step separates green from brown LAI by means of a newly proposed index, 'Green Brown Vegetation Index (GBVI)'. This index exploits two shortwave infrared (SWIR) spectral bands centred at 2100 and 2000 nm, which fall right in the dry matter absorption regions, thereby providing positive values for senescent vegetation and negative for green vegetation. The second step involves applying linear regression functions based on optimized vegetation indices to estimate green and brown LAI estimation respectively. While the green LAI index uses a band in the red and a band in the red-edge, the brown LAI index uses bands located in the same spectral region as GBVI, i.e. an absorption band located in the region of maximum absorption of cellulose and lignin at 2154 nm, and a reference band at 1635 nm where the absorption of both water and dry matter is low. The two-step approach was applied to a HyMap image acquired over an agroecosystem at the agricultural site Barrax, Spain.

  9. Uncertainty Analysis in the Creation of a Fine-Resolution Leaf Area Index (LAI) Reference Map for Validation of Moderate Resolution LAI Products

    EPA Science Inventory

    The validation process for a moderate resolution leaf area index (LAI) product (i.e., MODIS) involves the creation of a high spatial resolution LAI reference map (Lai-RM), which when scaled to the moderate LAI resolution (i.e., >1 km) allows for comparison and analysis with this ...

  10. Pathogenic Leptospira interrogans Exoproteins Are Primarily Involved in Heterotrophic Processes

    PubMed Central

    Eshghi, Azad; Pappalardo, Elisa; Hester, Svenja; Thomas, Benjamin; Pretre, Gabriela

    2015-01-01

    Leptospirosis is a life-threatening and emerging zoonotic disease with a worldwide annual occurrence of more than 1 million cases. Leptospirosis is caused by spirochetes belonging to the genus Leptospira. The mechanisms of disease manifestation in the host remain elusive, and the roles of leptospiral exoproteins in these processes have yet to be determined. Our aim in this study was to assess the composition and quantity of exoproteins of pathogenic Leptospira interrogans and to construe how these proteins contribute to disease pathogenesis. Label-free quantitative mass spectrometry of proteins obtained from Leptospira spirochetes cultured in vitro under conditions mimicking infection identified 325 exoproteins. The majority of these proteins are conserved in the nonpathogenic species Leptospira biflexa, and proteins involved in metabolism and energy-generating functions were overrepresented and displayed the highest relative abundance in culture supernatants. Conversely, proteins of unknown function, which represent the majority of pathogen-specific proteins (presumably involved in virulence mechanisms), were underrepresented. Characterization of various L. interrogans exoprotein mutants in the animal infection model revealed host mortality rates similar to those of hosts infected with wild-type L. interrogans. Collectively, these results indicate that pathogenic Leptospira exoproteins primarily function in heterotrophic processes (the processes by which organisms utilize organic substances as nutrient sources) to maintain the saprophytic lifestyle rather than the virulence of the bacteria. The underrepresentation of proteins homologous to known virulence factors, such as toxins and effectors in the exoproteome, also suggests that disease manifesting from Leptospira infection is likely caused by a combination of the primary and potentially moonlight functioning of exoproteins. PMID:25987703

  11. [Qijie theory of LAI's Tongyuan acupuncture technique].

    PubMed

    Zhuang, Juanjuan; Wang, Jihong; Lai, Xinsheng

    2016-05-01

    Qijie theory is one of the important components of TCM meridian and collateral system. It is the shortcut for the communication from the exterior to the interior and for the transverse connection, strengthens the therapeutic effects of acupuncture and moxibustion on the disorders of internal organs and enlarges the indications of acupoints. Professor LAI Xinsheng originally creats Tongyuan acupuncture technique. It is a kind of acupuncture therapeutic methods, including promoting the circulation of the governor vessel, regulating the mind and conducting qi to the origin. In order to analyze the connection between Tongyuan acupuncture technique and traditional meridian and collateral theory, the connotations of Tongyuan acupuncture technique and qijie, as well as the in-terrelationship between them are taken as the basis in the paper. By tracing the literature records, the original concept of qijie is detected. Through proving clinically Tongyuan acupuncture technique, it is revealed that qijie is the arrowhead on the main road of meridian qi circulation and is the essential connotation of the direct path of the body surface connecting with the deep layers of the body as well as the zangfu organs and tissues. It is summarized that the traditional qijie theory provides the powerful theoretic evidence for the treatment with Tongyuan acupuncture technique.

  12. Modelling LAI at a regional scale with ISBA-A-gs: comparison with satellite-derived LAI over southwestern France

    NASA Astrophysics Data System (ADS)

    Brut, A.; Rüdiger, C.; Lafont, S.; Roujean, J.-L.; Calvet, J.-C.; Jarlan, L.; Gibelin, A.-L.; Albergel, C.; Le Moigne, P.; Soussana, J.-F.; Klumpp, K.

    2009-04-01

    A CO2-responsive land surface model (the ISBA-A-gs model of Météo-France) is used to simulate photosynthesis and Leaf Area Index (LAI) in southwestern France for a 3-year period (2001-2003). A domain of about 170 000 km2 is covered at a spatial resolution of 8 km. The capability of ISBA-A-gs to reproduce the seasonal and the inter-annual variability of LAI at a regional scale, is assessed with two satellite-derived LAI products. One originates from the CYCLOPES programme using SPOT/VEGETATION data, and the second is based on MODIS data. The comparison reveals discrepancies between the two satellite LAI estimates and between satellite and simulated LAI values, both in their intensity and in the timing of the leaf onset. The model simulates higher LAI values for the C3 crops and coniferous trees than the satellite observations, which may be due to a saturation effect within the satellite signal. The simulated leaf onset presents a significant delay for mountainous grasslands. In-situ observations at a mid-altitude grassland site show that the generic temperature response of photosynthesis used in the model is not appropriate for plants adapted to the cold climatic conditions of the mountainous areas. This study demonstrates the potential of LAI remote sensing products for identifying and locating models' shortcomings at a regional scale.

  13. Modelling LAI at a regional scale with ISBA-A-gs: comparison with satellite-derived LAI over southwestern France

    NASA Astrophysics Data System (ADS)

    Brut, A.; Rüdiger, C.; Lafont, S.; Roujean, J.-L.; Calvet, J.-C.; Jarlan, L.; Gibelin, A.-L.; Albergel, C.; Le Moigne, P.; Soussana, J.-F.; Klumpp, K.; Guyon, D.; Wigneron, J.-P.; Ceschia, E.

    2009-08-01

    A CO2-responsive land surface model (the ISBA-A-gs model of Météo-France) is used to simulate photosynthesis and Leaf Area Index (LAI) in southwestern France for a 3-year period (2001-2003). A domain of about 170 000 km2 is covered at a spatial resolution of 8 km. The capability of ISBA-A-gs to reproduce the seasonal and the interannual variability of LAI at a regional scale, is assessed with satellite-derived LAI products. One originates from the CYCLOPES programme using SPOT/VEGETATION data, and two products are based on MODIS data. The comparison reveals discrepancies between the satellite LAI estimates and between satellite and simulated LAI values, both in their intensity and in the timing of the leaf onset. The model simulates higher LAI values for the C3 crops than the satellite observations, which may be due to a saturation effect within the satellite signal or to uncertainties in model parameters. The simulated leaf onset presents a significant delay for C3 crops and mountainous grasslands. In-situ observations at a mid-altitude grassland site show that the generic temperature response of photosynthesis used in the model is not appropriate for plants adapted to the cold climatic conditions of the mountainous areas. This study demonstrates the potential of LAI remote sensing products for identifying and locating models' shortcomings at a regional scale.

  14. BOREAS RSS-7 LAI, Gap Fraction, and FPAR Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Chen, Jing

    2000-01-01

    The BOREAS RSS-7 team collected various data sets to develop and validate an algorithm to allow the retrieval of the spatial distribution of Leaf Area Index (LAI) from remotely sensed images. Ground measurements of LAI and Fraction of Photosynthetically Active Radiation (FPAR) absorbed by the plant canopy were made using the LAI-2000 and TRAC optical instruments during focused periods from 09-Aug-1993 to 19-Sep-1994. The measurements were intensive at the NSA and SSA tower sites, but were made just once or twice at auxiliary sites. The final processed LAI and FPAR data set is contained in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884).

  15. Retrieving LAI and FPAR from MERIS Data With Advanced Algorithms

    NASA Technical Reports Server (NTRS)

    Myneni, Ranga B.

    2001-01-01

    The primary motivation of this research activity is to document the feasibility of deriving global fields of LAI (leaf area index) and FPAR (fraction of photosynthetically active radiation absorbed by vegetation) from atmosphere corrected ESA (European Space Agency) MERIS (Medium Resolution Imaging Spectrometer) data, validate and evaluate the MERIS LAI and FPAR products by intercomparison with MODIS (Moderate Resolution Imaging Spectrometer) LAI and FPAR products and with field data collected at the EOS Core sites distributed around the world. Our activities during Year 1 (January through December, 2001) have focused on the modification of the MODIS LAI/FPAR algorithm to facilitate its ability to process MERIS data. We considered a related but wider problem, i.e., fusion of biophysical parameters derived from data acquired by spectroradiometers of different spectral bands and different resolutions.

  16. Use of luminescent Leptospira interrogans for enumeration in biological assays.

    PubMed

    Murray, Gerald L; King, Amy M; Srikram, Amporn; Sermswan, Rasana W; Adler, Ben

    2010-06-01

    Rapid and reliable in vitro methods for the detection of pathogenic leptospires, such as Leptospira interrogans, are lacking. The present study investigated the use of luminescence to replace the existing enumeration techniques. Transposon TnSC189 was modified to incorporate the luxCDABE cassette from Photorhabdus luminescens and was used to construct luminescent Leptospira spp. There was a linear relationship between luminescence and cell number, with the theoretical detection limit being less than 10(4) leptospires. A comparison of enumeration by a standard method (counting by dark-field microscopy) and enumeration by luminescence was conducted with luminescent L. interrogans. There was a good correlation between the two methods of enumeration (R(2) = 0.766), although variation in the luminescence early and late in growth phase reduced the degree of correlation. To demonstrate the utility of luminescence as a viability and cell number reporter, in vitro assays, including MIC determination, an extracellular matrix binding experiment, and a complement killing experiment, were conducted. In each case, the results obtained by luminescence matched those obtained by traditional means with high correlations (binding assay R(2) = 0.916, complement killing assay R(2) = 0.988). A strain expressing the luxCDABE transposon retained virulence in the hamster model of infection. Despite some variation in luminescence as a result of the growth phase or the particular assay conditions, enumeration by luminescence was found to be a quick, reliable, and highly sensitive method for the in vitro detection of leptospires that has the potential to replace more time-consuming methods of enumeration.

  17. Characterization of two new putative adhesins of Leptospira interrogans.

    PubMed

    Figueredo, Jupciana M; Siqueira, Gabriela H; de Souza, Gisele O; Heinemann, Marcos B; Vasconcellos, Silvio A; Chapola, Erica G B; Nascimento, Ana L T O

    2017-01-01

    We here report the characterization of two novel proteins encoded by the genes LIC11122 and LIC12287, identified in the genome sequences of Leptospira interrogans, annotated, respectively, as a putative sigma factor and a hypothetical protein. The CDSs LIC11122 and LIC12287 have signal peptide SPII and SPI and are predicted to be located mainly at the cytoplasmic membrane of the bacteria. The genes were cloned and the proteins expressed using Escherichia coli. Proteinase K digestion showed that both proteins are surface exposed. Evaluation of interaction of recombinant proteins with extracellular matrix components revealed that they are laminin binding and they were called Lsa19 (LIC11122) and Lsa14 (LIC12287), for Leptospiral-surface adhesin of 19 and 14 kDa, respectively. The bindings were dose-dependent on protein concentration, reaching saturation, fulfilling the ligand-binding criteria. Reactivity of the recombinant proteins with leptospirosis human sera has shown that Lsa19 and, to a lesser extent, Lsa14, are recognized by antibodies, suggesting that, most probably, Lsa19 is expressed during infection. The proteins interact with plasminogen and generate plasmin in the presence of urokinase-type plasminogen activator. Plasmin generation in Leptospira has been associated with tissue penetration and immune evasion strategies. The presence of a sigma factor on the cell surface playing a secondary role, probably mediating host -pathogen interaction, suggests that LIC11122 is a moonlighting protein candidate. Although the biological significance of these putative adhesins will require the generation of mutants, our data suggest that Lsa19 is a potential candidate for future evaluation of its role in adhesion/colonization activities during L. interrogans infection.

  18. Comparison among normalized vegetation indices for the determination of LAI

    NASA Astrophysics Data System (ADS)

    Bernasconi, Luca; Pippi, Ivan; Raddi, Sabrina

    2003-03-01

    Airborne hyperspectral images collected over San Rossore Natural Park (Pisa, Italy) by the Multispectral Infrared and Visible Imaging Spectrometer (MIVIS) on June 21st, 2000 were analyzed in order to assess the best indices for forest LAI estimation. Hemispherical photography was used for ground truth measurements, simultaneously with the overflights, in hardwood and conifer stands characterized by a LAI ranging between 1.2 and 4.5. All band combinations expressed as simple ratios and normalized indices (a total of 89 single bands, and 7832 and 3916 indices, respectively) were linearly correlated to LAI in order to detect the best correlations. Determination coefficients were analyzed by means of a graphical matrix to highlight relevant spectral regions. Normalized indices composed by the red chlorophyll absorption wavelength (680 nm) and the wavelengths after the green reflectance peak (580-640 nm) in the orange region were strongly correlated to LAI. Best results were obtained with the newly proposed Orange Slope Vegetation Index [OSVI=(ρ620-ρ680)/(ρ620+ρ680), R2=0.88, RMSE=0.5). The index performed better than the normalized difference vegetation index (NDVI=(ρ780-ρ680)/(ρ780+ρ680), R2=0.47) Using SAIL radiative transfer model, canopy reflectance at different viewing angles and a wide range of LAI was simulated in order to verify the sensitivity of OSVI and NDVI. For LAI between 0.25 and 8 both indices resulted stable for viewing zenith angles between -60° and +60°. OSVI, being saturated with values greater than 4, could be used to estimate a wider range of LAI than NDVI. Application of GeoSail model resulted in a good agreement between simulated and measured OSVI.

  19. Framework for automated spatio-temporal enhancement of coarse resolution leaf area index (FASE-LAI) – Application to MODIS LAI

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A multi-scale satellite-based Framework for Automated Spatio-temporal Enhancement of coarse-resolution leaf area index (LAI) products (FASE-LAI) has ben established to generate 4-day time-series of Landsat-scale LAI, thereby meeting the critical demands of applications needing frequent and high spat...

  20. A Comprehensive Approach to Identification of Surface-Exposed, Outer Membrane-Spanning Proteins of Leptospira interrogans

    PubMed Central

    Pinne, Marija; Haake, David A.

    2009-01-01

    Leptospirosis is a zoonosis with worldwide distribution caused by pathogenic spirochetes belonging to the genus Leptospira. The leptospiral life cycle involves transmission via fresh water and colonization of the renal tubules of their reservoir hosts or infection of accidental hosts, including humans. Bacterial outer membrane proteins (OMPs), particularly those with surface-exposed regions, play crucial roles in virulence mechanisms of pathogens and the adaptation to various environmental conditions, including those of the mammalian host. Little is known about the surface-exposed OMPs in Leptospira, particularly those with outer membrane-spanning domains. Herein, we describe a comprehensive strategy for identification and characterization of leptospiral transmembrane OMPs. The genomic sequence of L. interrogans serovar Copenhageni strain Fiocruz L1–130 allowed us to employ the β-barrel prediction programs, PRED-TMBB and TMBETA-NET, to identify potential transmembrane OMPs. Several complementary methods were used to characterize four novel OMPs, designated OmpL36, OmpL37, OmpL47 and OmpL54. In addition to surface immunofluorescence and surface biotinylation, we describe surface proteolysis of intact leptospires as an improved method for determining the surface exposure of leptospiral proteins. Membrane integration was confirmed using techniques for removal of peripheral membrane proteins. We also demonstrate deficiencies in the Triton X-114 fractionation method for assessing the outer membrane localization of transmembrane OMPs. Our results establish a broadly applicable strategy for the elucidation of novel surface-exposed outer membrane-spanning proteins of Leptospira, an essential step in the discovery of potential virulence factors, diagnostic antigens and vaccine candidates. PMID:19562037

  1. Characterization of Leptospira isolates from serovar hardjo by ribotyping, arbitrarily primed PCR, and mapped restriction site polymorphisms.

    PubMed

    Perolat, P; Merien, F; Ellis, W A; Baranton, G

    1994-08-01

    Leptospira serovar hardjo isolates of the hardjoprajitno and hardjobovis genotypes were characterized by ribotyping, arbitrarily primed PCR (AP-PCR) fingerprinting, and the study of mapped restriction site polymorphisms (MRSPs) in rrs and rrl genes. After restriction of chromosomal DNA with BglII, EcoRI, or HindIII, each genotype was individualized with a distinct ribotype. The fingerprints produced by AP-PCR with seven primers clearly separated the two groups; primers KF and RSP produced species-specific products which assigned hardjoprajitno and hardjobovis isolates to the species L. interrogans sensu stricto and L. borgpetersenii, respectively. Furthermore, AP-PCR fingerprints gave evidence of a considerable genomic heterogeneity at the strain level among the hardjobovis group. Conversely, the hardjoprajitno group was homogeneous. MRSP profiles in ribosomal genes indicated that hardjoprajitno and hardjobovis isolates belonged to L. interrogans MRSP group B and L. borgpetersenii group C, respectively. AP-PCR and determination of MRSPs in ribosomal genes proved to be quick and reliable methods for typing Leptospira strains and for studying intraspecific population structures.

  2. Transcriptional response of Leptospira interrogans to iron limitation and characterization of a PerR homolog

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leptospira interrogans is the causative agent of leptospirosis, a zoonosis of global significance. Iron is essential for growth of most bacterial species. Since availability of iron is low in the host, pathogens have evolved complex iron acquisition mechanisms to survive and establish infection. In ...

  3. Spatially and temporally continuous LAI datasets based on the mixed pixel decomposition method.

    PubMed

    Zhao, Jianjun; Wang, Yanying; Zhang, Hongyan; Zhang, Zhengxiang; Guo, Xiaoyi; Yu, Shan; Du, Wala

    2016-01-01

    The leaf area index (LAI) is a key biophysical parameter that determines the state of plant growth. A global LAI has been routinely produced by the Moderate Resolution Imaging Spectro-radiometer (MODIS) and Advanced Very High Resolution Radiometer (AVHRR). However, the MODIS and AVHRR LAI products cannot be synchronized with the same spatial and temporal resolution. The LAI features are not discernible when a global LAI product is implemented at the regional scale because it has low resolution and different land cover types. To obtain high spatial and temporal resolution of LAI products, an empirical model based on the pixel scale was developed. The approach to generate a long (multi-decade) time series of a 1-km spatial resolution LAI normally integrates both AVHRR and MODIS datasets for different land cover types. In this paper, a regression-based model for generating a vegetation LAI was developed using the AVHRR Global Inventory Modelling and Mapping Studies Normalized Difference Vegetation Index (NDVI), MODIS LAI and land cover as input data; the model was evaluated by using relevant data from the same period data from 2000 to 2006. The results of this method show a good consistency in LAI values retrieved from the AVHRR NDVI and MODIS LAI. This simple method has no specific-limited data requirements and can provide improved spatial and temporal resolution in a region without ground data.

  4. Linking in situ LAI and fine resolution remote sensing data to map reference LAI over cropland and grassland using geostatistical regression method

    NASA Astrophysics Data System (ADS)

    He, Yaqian; Bo, Yanchen; Chai, Leilei; Liu, Xiaolong; Li, Aihua

    2016-08-01

    Leaf Area Index (LAI) is an important parameter of vegetation structure. A number of moderate resolution LAI products have been produced in urgent need of large scale vegetation monitoring. High resolution LAI reference maps are necessary to validate these LAI products. This study used a geostatistical regression (GR) method to estimate LAI reference maps by linking in situ LAI and Landsat TM/ETM+ and SPOT-HRV data over two cropland and two grassland sites. To explore the discrepancies of employing different vegetation indices (VIs) on estimating LAI reference maps, this study established the GR models for different VIs, including difference vegetation index (DVI), normalized difference vegetation index (NDVI), and ratio vegetation index (RVI). To further assess the performance of the GR model, the results from the GR and Reduced Major Axis (RMA) models were compared. The results show that the performance of the GR model varies between the cropland and grassland sites. At the cropland sites, the GR model based on DVI provides the best estimation, while at the grassland sites, the GR model based on DVI performs poorly. Compared to the RMA model, the GR model improves the accuracy of reference LAI maps in terms of root mean square errors (RMSE) and bias.

  5. Modeling the effect of photosynthetic vegetation properties on the NDVI--LAI relationship.

    PubMed

    Steltzer, Heidi; Welker, Jeffrey M

    2006-11-01

    Developing a relationship between the normalized difference vegetation index (NDVI) and the leaf area index (LAI) is essential to describe the pattern of spatial or temporal variation in LAI that controls carbon, water, and energy exchange in many ecosystem process models. Photosynthetic vegetation (PV) properties can affect the estimation of LAI, but no models integrate the effects of multiple species. We developed four alternative NDVI-LAI models, three of which integrate PV effects: no PV effects, leaf-level effects, canopy-level effects, and effects at both levels. The models were fit to data across the natural range of variation in NDVI for a widespread High Arctic ecosystem. The weight of evidence supported the canopy-level model (Akaike weight, wr = 0.98), which includes species-specific canopy coefficients that primarily scale fractional PV cover to LAI by accounting for the area of unexposed PV. Modeling the canopy-level effects improved prediction of LAI (R2 = 0.82) over the model with no PV effect (R2 = 0.71) across the natural range of variation in NDVI but did not affect the site-level estimate of LAI. Satellite-based methods to estimate species composition, a variable in the model, will need to be developed. We expect that including the effects of PV properties in NDVI-LAI models will improve prediction of LAI where species composition varies across space or changes over time.

  6. Modeling uncertainties in estimation of canopy LAI from hyperspectral remote sensing data - A Bayesian approach

    NASA Astrophysics Data System (ADS)

    Varvia, Petri; Rautiainen, Miina; Seppänen, Aku

    2017-04-01

    Hyperspectral remote sensing data carry information on the leaf area index (LAI) of forests, and thus in principle, LAI can be estimated based on the data by inverting a forest reflectance model. However, LAI is usually not the only unknown in a reflectance model; especially, the leaf spectral albedo and understory reflectance are also not known. If the uncertainties of these parameters are not accounted for, the inversion of a forest reflectance model can lead to biased estimates for LAI. In this paper, we study the effects of reflectance model uncertainties on LAI estimates, and further, investigate whether the LAI estimates could recover from these uncertainties with the aid of Bayesian inference. In the proposed approach, the unknown leaf albedo and understory reflectance are estimated simultaneously with LAI from hyperspectral remote sensing data. The feasibility of the approach is tested with numerical simulation studies. The results show that in the presence of unknown parameters, the Bayesian LAI estimates which account for the model uncertainties outperform the conventional estimates that are based on biased model parameters. Moreover, the results demonstrate that the Bayesian inference can also provide feasible measures for the uncertainty of the estimated LAI.

  7. Leptospira interrogans catalase is required for resistance to H2O2 and for virulence.

    PubMed

    Eshghi, Azad; Lourdault, Kristel; Murray, Gerald L; Bartpho, Thanatchaporn; Sermswan, Rasana W; Picardeau, Mathieu; Adler, Ben; Snarr, Brendan; Zuerner, Richard L; Cameron, Caroline E

    2012-11-01

    Pathogenic Leptospira spp. are likely to encounter higher concentrations of reactive oxygen species induced by the host innate immune response. In this study, we characterized Leptospira interrogans catalase (KatE), the only annotated catalase found within pathogenic Leptospira species, by assessing its role in resistance to H(2)O(2)-induced oxidative stress and during infection in hamsters. Pathogenic L. interrogans bacteria had a 50-fold-higher survival rate under H(2)O(2)-induced oxidative stress than did saprophytic L. biflexa bacteria, and this was predominantly catalase dependent. We also characterized KatE, the only annotated catalase found within pathogenic Leptospira species. Catalase assays performed with recombinant KatE confirmed specific catalase activity, while protein fractionation experiments localized KatE to the bacterial periplasmic space. The insertional inactivation of katE in pathogenic Leptospira bacteria drastically diminished leptospiral viability in the presence of extracellular H(2)O(2) and reduced virulence in an acute-infection model. Combined, these results suggest that L. interrogans KatE confers in vivo resistance to reactive oxygen species induced by the host innate immune response.

  8. Evaluation and Validation of Updated MODIS C6 and VIIRS LAI/FPAR

    NASA Astrophysics Data System (ADS)

    Yan, K.; Park, T.; Chen, C.; Yang, B.; Yan, G.; Knyazikhin, Y.; Myneni, R. B.; CHOI, S.

    2015-12-01

    Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (0.4-0.7 μm) absorbed by vegetation (FPAR) play a key role in characterizing vegetation canopy functioning and energy absorption capacity. With radiative transfer realization, MODIS onboard NASA EOS Terra and Aqua satellites has provided globally continuous LAI/FPAR since 2000 and continuously updated the products with better quality. And NPP VIIRS shows the measurement capability to extend high-quality LAI/FPAR time series data records as a successor of MODIS. The primary objectives of this study are 1) to evaluate and validate newly updated MODIS Collection 6 (C6) LAI/FPAR product which has finer resolution (500m) and improved biome type input, and 2) to examine and adjust VIIRS LAI/FPAR algorithm for continuity with MODIS'. For MODIS C6 investigation, we basically measure the spatial coverage (i.e., main radiative transfer algorithm execution), continuity and consistency with Collection 5 (C5), and accuracy with field measured LAI/FPAR. And we also validate C6 LAI/FPAR via comparing other possible global LAI/FPAR products (e.g., GLASS and CYCLOPES) and capturing co-varying seasonal signatures with climatic variables (e.g., temperature and precipitation). For VIIRS evaluation and adjustment, we first quantify possible difference between C5 and MODIS heritage based VIIRS LAI/FPAR. Then based on the radiative transfer theory of canopy spectral invariants, we find VIIRS- and biome-specific configurable parameters (single scattering albedo and uncertainty). These two practices for MODIS C6 and VIIRS LAI/FPAR products clearly suggest that (a) MODIS C6 has better coverage and accuracy than C5, (b) C6 shows consistent spatiotemporal pattern with C5, (c) VIIRS has the potential for producing MODIS-like global LAI/FPAR Earth System Data Records.

  9. Comparing LAI estimates of corn and soybean from vegetation indices of multi-resolution satellite images

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaf area index (LAI) is important in explaining the ability of the crop to intercept solar energy for biomass production and in understanding the impact of crop management practices. This paper describes a procedure for estimating LAI as a function of image-derived vegetation indices from temporal ...

  10. Sensitivity analysis for leaf area index (LAI) estimation from CHRIS/PROBA data

    NASA Astrophysics Data System (ADS)

    Cao, Jianjun; Gu, Zhujun; Xu, Jianhua; Duan, Yushan; Liu, Yongmei; Liu, Yongjuan; Li, Dongliang

    2014-09-01

    Sensitivity analyses were conducted for the retrieval of vegetation leaf area index (LAI) from multiangular imageries in this study. Five spectral vegetation indices (VIs) were derived from Compact High Resolution Imaging Spectrometer onboard the Project for On Board Autonomy (CHRIS/PROBA) images, and were related to LAI, acquired from in situ measurement in Jiangxi Province, China, for five vegetation communities. The sensitivity of LAI retrieval to the variation of VIs from different observation angles was evaluated using the ratio of the slope of the best-fit linear VI-LAI model to its root mean squared error. Results show that both the sensitivity and reliability of VI-LAI models are influenced by the heterogeneity of vegetation communities, and that performance of vegetation indices in LAI estimation varies along observation angles. The VI-LAI models are more reliable for tall trees than for low growing shrub-grasses and also for forests with broad leaf trees than for coniferous forest. The greater the tree height and leaf size, the higher the sensitivity. Forests with broad-leaf trees have higher sensitivities, especially at oblique angles, while relatively simple-structured coniferous forests, shrubs, and grasses show similar sensitivities at all angles. The multi-angular soil and/or atmospheric parameter adjustments will hopefully improve the performance of VIs in LAI estimation, which will require further investigation.

  11. Retrieving LAI from Remotely Sensed Images: Spectral Indices vs. Spatial Texture

    NASA Astrophysics Data System (ADS)

    Song, C.; Gray, J. M.; Zhang, S.

    2008-12-01

    Leaves are the interface where energy and gas exchanges between the atmosphere and forest ecosystems occur. Accurate knowledge of the amount leaves is essential to successfully modeling the fluxes of water and carbon through the earth's forests. Leaf area index (LAI) is a parameter used to quantify the abundance of leaves in a given stand. Remote sensing offers the only feasible way to quantify LAI over large areas. Tremendous efforts have been devoted to this task by remote sensing scientists, but there is still a lack of concensus on how LAI can be best retrieved. Though global LAI products are available, their accuracy has remained unsatisfactory for regional applications. Previous work has primarily focused on using the spectral information in remotely sensed imagery. In this study, we compared the potential of LAI retrieval from various spectral indices derived from Landsat TM images with retrieval using the spatial information, image texture, derived from the Ikonos images. LAI on the ground was derived from allometry, LAI-2000 and the TRAC device in the Duke Forest area in central North Carolina. Our results show that the commonly used spectral indices, normalized difference vegetation index (NDVI) and simple ratio vegetation index (SRVI) were not the best choice for LAI retrieval. We found that Landsat TM derived Structural Index (SI=TM4/TM5) and normalized difference water index (NDWI), as well as Ikonos image texture are much better alternatives.

  12. Towards an improved LAI collection protocol via simulated field-based PAR sensing

    DOE PAGES

    Yao, Wei; Van Leeuwen, Martin; Romanczyk, Paul; ...

    2016-07-14

    In support of NASA’s next-generation spectrometer—the Hyperspectral Infrared Imager (HyspIRI)—we are working towards assessing sub-pixel vegetation structure from imaging spectroscopy data. Of particular interest is Leaf Area Index (LAI), which is an informative, yet notoriously challenging parameter to efficiently measure in situ. While photosynthetically-active radiation (PAR) sensors have been validated for measuring crop LAI, there is limited literature on the efficacy of PAR-based LAI measurement in the forest environment. This study (i) validates PAR-based LAI measurement in forest environments, and (ii) proposes a suitable collection protocol, which balances efficiency with measurement variation, e.g., due to sun flecks and various-sized canopymore » gaps. A synthetic PAR sensor model was developed in the Digital Imaging and Remote Sensing Image Generation (DIRSIG) model and used to validate LAI measurement based on first-principles and explicitly-known leaf geometry. Simulated collection parameters were adjusted to empirically identify optimal collection protocols. Furthermore, these collection protocols were then validated in the field by correlating PAR-based LAI measurement to the normalized difference vegetation index (NDVI) extracted from the “classic” Airborne Visible Infrared Imaging Spectrometer (AVIRIS-C) data (R2 was 0.61). The results indicate that our proposed collecting protocol is suitable for measuring the LAI of sparse forest (LAI < 3–5 ( m2/m2)).« less

  13. Towards an improved LAI collection protocol via simulated field-based PAR sensing

    SciTech Connect

    Yao, Wei; Van Leeuwen, Martin; Romanczyk, Paul; van Aardt, Jan; Kelbe, David

    2016-07-14

    In support of NASA’s next-generation spectrometer—the Hyperspectral Infrared Imager (HyspIRI)—we are working towards assessing sub-pixel vegetation structure from imaging spectroscopy data. Of particular interest is Leaf Area Index (LAI), which is an informative, yet notoriously challenging parameter to efficiently measure in situ. While photosynthetically-active radiation (PAR) sensors have been validated for measuring crop LAI, there is limited literature on the efficacy of PAR-based LAI measurement in the forest environment. This study (i) validates PAR-based LAI measurement in forest environments, and (ii) proposes a suitable collection protocol, which balances efficiency with measurement variation, e.g., due to sun flecks and various-sized canopy gaps. A synthetic PAR sensor model was developed in the Digital Imaging and Remote Sensing Image Generation (DIRSIG) model and used to validate LAI measurement based on first-principles and explicitly-known leaf geometry. Simulated collection parameters were adjusted to empirically identify optimal collection protocols. Furthermore, these collection protocols were then validated in the field by correlating PAR-based LAI measurement to the normalized difference vegetation index (NDVI) extracted from the “classic” Airborne Visible Infrared Imaging Spectrometer (AVIRIS-C) data (R2 was 0.61). The results indicate that our proposed collecting protocol is suitable for measuring the LAI of sparse forest (LAI < 3–5 ( m2/m2)).

  14. Towards an Improved LAI Collection Protocol via Simulated and Field-Based PAR Sensing

    PubMed Central

    Yao, Wei; Kelbe, David; van Leeuwen, Martin; Romanczyk, Paul; van Aardt, Jan

    2016-01-01

    In support of NASA’s next-generation spectrometer—the Hyperspectral Infrared Imager (HyspIRI)—we are working towards assessing sub-pixel vegetation structure from imaging spectroscopy data. Of particular interest is Leaf Area Index (LAI), which is an informative, yet notoriously challenging parameter to efficiently measure in situ. While photosynthetically-active radiation (PAR) sensors have been validated for measuring crop LAI, there is limited literature on the efficacy of PAR-based LAI measurement in the forest environment. This study (i) validates PAR-based LAI measurement in forest environments, and (ii) proposes a suitable collection protocol, which balances efficiency with measurement variation, e.g., due to sun flecks and various-sized canopy gaps. A synthetic PAR sensor model was developed in the Digital Imaging and Remote Sensing Image Generation (DIRSIG) model and used to validate LAI measurement based on first-principles and explicitly-known leaf geometry. Simulated collection parameters were adjusted to empirically identify optimal collection protocols. These collection protocols were then validated in the field by correlating PAR-based LAI measurement to the normalized difference vegetation index (NDVI) extracted from the “classic” Airborne Visible Infrared Imaging Spectrometer (AVIRIS-C) data (R2 was 0.61). The results indicate that our proposed collecting protocol is suitable for measuring the LAI of sparse forest (LAI < 3–5 (m2/m2)). PMID:27428969

  15. Jointly assimilating MODIS LAI and ET products into SWAP model for winter wheat yield estimation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaf Area Index (LAI) and Evapotranspiration (ET) are two key biophysical variables related to crop growth and grain yield. This study presents a framework to assimilate MODIS LAI products (MCD15A3) and MODIS ET products (MOD16A2) into the soil water atmosphere plant (SWAP) model to improve estimate...

  16. Application and Evaluation of MODIS LAI, fPAR, and Albedo Products in the WRFCMAQ System

    EPA Science Inventory

    Leaf area index (LAI), vegetation fraction (VF), and surface albedo are important parameters in the land surface model (LSM) for meteorology and air quality modeling systems such as WRF/CMAQ. LAI and VF control not only leaf to canopy level evapotranspiration flux scaling but al...

  17. [The study of LAI estimation using a new vegetation index based on CHRIS data].

    PubMed

    Wang, Li-Juan; Niu, Zheng; Hou, Xue-Hui; Gao, Shuai

    2013-04-01

    Leaf area index (LAI) is an important structural parameter of vegetation canopy, the correct estimation of which has been the focus in the remote sensing community. As a kind of hyperspectral and multi-angle remote sensing data with higher resolution (17 m), PROBA/CHRIS has significant application value in LAI inversion. In the present paper, the analytical two-layer canopy reflectance model (ACRM) was used to simulate a series of reflectances with different LAI values. Based on this, a new vegetation index was built and successfully applied to LAI inversion of PROBA/CHRIS image data. Our results indicated that: compared with the spectral index NDVI and multi-angle index HDS, the new index could make better use of spectrum and multi-angle messages and have a better correlation with LAI of the study area; moreover, the correlation coefficient R2 reached up to 0.734 7. And in order to obtain the figure of LAI distribution of the study area, we used the optimal fit equation between LAI and HDVI to estimate LAI, and the accuracy of the RMSE was 0.619 8.

  18. Towards an Improved LAI Collection Protocol via Simulated and Field-Based PAR Sensing.

    PubMed

    Yao, Wei; Kelbe, David; Leeuwen, Martin van; Romanczyk, Paul; Aardt, Jan van

    2016-07-14

    In support of NASA's next-generation spectrometer-the Hyperspectral Infrared Imager (HyspIRI)-we are working towards assessing sub-pixel vegetation structure from imaging spectroscopy data. Of particular interest is Leaf Area Index (LAI), which is an informative, yet notoriously challenging parameter to efficiently measure in situ. While photosynthetically-active radiation (PAR) sensors have been validated for measuring crop LAI, there is limited literature on the efficacy of PAR-based LAI measurement in the forest environment. This study (i) validates PAR-based LAI measurement in forest environments, and (ii) proposes a suitable collection protocol, which balances efficiency with measurement variation, e.g., due to sun flecks and various-sized canopy gaps. A synthetic PAR sensor model was developed in the Digital Imaging and Remote Sensing Image Generation (DIRSIG) model and used to validate LAI measurement based on first-principles and explicitly-known leaf geometry. Simulated collection parameters were adjusted to empirically identify optimal collection protocols. These collection protocols were then validated in the field by correlating PAR-based LAI measurement to the normalized difference vegetation index (NDVI) extracted from the "classic" Airborne Visible Infrared Imaging Spectrometer (AVIRIS-C) data ( R 2 was 0.61). The results indicate that our proposed collecting protocol is suitable for measuring the LAI of sparse forest (LAI < 3-5 ( m 2 / m 2 )).

  19. Deriving Leaf Area Index (LAI) from multiple lidar remote sensing systems

    NASA Astrophysics Data System (ADS)

    Tang, H.; Dubayah, R.; Zhao, F.

    2012-12-01

    LAI is an important biophysical variable linking biogeochemical cycles of earth systems. Observations with passive optical remote sensing are plagued by saturation and results from different passive and active sensors are often inconsistent. Recently lidar remote sensing has been applied to derive vertical canopy structure including LAI and its vertical profile. In this research we compare LAI retrievals from three different types of lidar sensors. The study areas include the La Selva Biological Station in Costa Rica and Sierra Nevada Forest in California. We first obtain independent LAI estimates from different lidar systems including airborne lidar (LVIS), spaceborne lidar (GLAS) and ground lidar (Echidna). LAI retrievals are then evaluated between sensors as a function of scale, land cover type and sensor characteristics. We also assess the accuracy of these LAI products against ground measurements. By providing a link between ground observations, ground lidar, aircraft and space-based lidar we hope to demonstrate a path for deriving more accurate estimates of LAI on a global basis, and to provide a more robust means of validating passive optical estimates of this important variable.

  20. Purification and characterization of a Na+, K+ ATPase inhibitor found in an endotoxin of Leptospira interrogans.

    PubMed Central

    Burth, P; Younes-Ibrahim, M; Gonçalez, F H; Costa, E R; Faria, M V

    1997-01-01

    We showed previously that the glycolipoprotein fraction prepared from Leptospira interrogans inhibited the Na+,K+ ATPase enzyme purified from brain or kidney and in isolated nephron segments (M. Younes-Ibrahim, P. Burth, M. V. Castro Faria, B. Buffin-Meyer, S. Marsy, C. Barlet-Bas, L. Cheval, and A. Doucet, C. R. Acad. Sci. Paris Ser. III 318:619-625, 1995). In the present communication, we have demonstrated that unsaturated fatty acids such as oleic and palmitoleic acids, which are adsorbed to this fraction, are effective inhibitors of the enzyme. PMID:9119504

  1. Estimating forest LAI profiles and structural parameters using a ground-based laser called 'Echidna'.

    PubMed

    Jupp, David L B; Culvenor, D S; Lovell, J L; Newnham, G J; Strahler, A H; Woodcock, C E

    2009-02-01

    There are many techniques for measuring leaf area index (LAI) and forest canopy foliage profiles but their accuracy is questionable. This paper briefly reviews current methods of estimating forest LAI and presents a novel, ground-based laser system, Echidna that can make a wide range of measurements of forest structure, including LAI. Here, use of the system to provide field data and derived gap probabilities in the form of a 'hemispherical photograph with range' is demonstrated. The results show consistency and reproducibility and do not depend on special conditions for the natural light field.

  2. Constructing seasonal LAI trajectory by data-model fusion for global evergreen needle-leaf forests

    NASA Astrophysics Data System (ADS)

    Wang, R.; Chen, J.; Mo, G.

    2010-12-01

    For decades, advancements in optical remote sensors made it possible to produce maps of a biophysical parameter--the Leaf Area Index (LAI), which is critically necessary in regional and global modeling of exchanges of carbon, water, energy and other substances, across large areas in a fast way. Quite a few global LAI products have been generated since 2000, e.g. GLOBCARBON (Deng et al., 2006), MODIS Collection 5 (Shabanov et al., 2007), CYCLOPES (Baret et al., 2007), etc. Albeit these progresses, the basic physics behind the technology restrains it from accurate estimation of LAI in winter, especially for northern high-latitude evergreen needle-leaf forests. Underestimation of winter LAI in these regions has been reported in literature (Yang et al., 2000; Cohen et al., 2003; Tian et al., 2004; Weiss et al., 2007; Pisek et al., 2007), and the distortion is usually attributed to the variations of canopy reflectance caused by understory change (Weiss et al., 2007) as well as by the presence of ice and snow on leaves and ground (Cohen, 2003; Tian et al., 2004). Seasonal changes in leaf pigments can also be another reason for low LAI retrieved in winter. Low conifer LAI values in winter retrieved from remote sensing make them unusable for surface energy budget calculations. To avoid these drawbacks of remote sensing approaches, we attempt to reconstruct the seasonal LAI trajectory through model-data fusion. A 1-degree LAI map of global evergreen needle-leaf forests at 10-day interval is produced based on the carbon allocation principle in trees. With net primary productivity (NPP) calculated by the Boreal Ecosystems Productivity Simulator (BEPS) (Chen et al., 1999), carbon allocated to needles is quantitatively evaluated and then can be further transformed into LAI using the specific leaf area (SLA). A leaf-fall scheme is developed to mimic the carbon loss caused by falling needles throughout the year. The seasonally maximum LAI from remote sensing data for each pixel

  3. Directional effects on NDVI and LAI retrievals from MODIS: A case study in Brazil with soybean

    NASA Astrophysics Data System (ADS)

    Breunig, Fábio Marcelo; Galvão, Lênio Soares; Formaggio, Antônio Roberto; Epiphanio, José Carlos Neves

    2011-02-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) is largely used to estimate Leaf Area Index (LAI) using radiative transfer modeling (the "main" algorithm). When this algorithm fails for a pixel, which frequently occurs over Brazilian soybean areas, an empirical model (the "backup" algorithm) based on the relationship between the Normalized Difference Vegetation Index (NDVI) and LAI is utilized. The objective of this study is to evaluate directional effects on NDVI and subsequent LAI estimates using global (biome 3) and local empirical models, as a function of the soybean development in two growing seasons (2004-2005 and 2005-2006). The local model was derived from the pixels that had LAI values retrieved from the main algorithm. In order to keep the reproductive stage for a given cultivar as a constant factor while varying the viewing geometry, pairs of MODIS images acquired in close dates from opposite directions (backscattering and forward scattering) were selected. Linear regression relationships between the NDVI values calculated from these two directions were evaluated for different view angles (0-25°; 25-45°; 45-60°) and development stages (<45; 45-90; >90 days after planting). Impacts on LAI retrievals were analyzed. Results showed higher reflectance values in backscattering direction due to the predominance of sunlit soybean canopy components towards the sensor and higher NDVI values in forward scattering direction due to stronger shadow effects in the red waveband. NDVI differences between the two directions were statistically significant for view angles larger than 25°. The main algorithm for LAI estimation failed in the two growing seasons with gradual crop development. As a result, up to 94% of the pixels had LAI values calculated from the backup algorithm at the peak of canopy closure. Most of the pixels selected to compose the 8-day MODIS LAI product came from the forward scattering view because it displayed larger LAI values than the

  4. A Bioinformatic Approach to Inter Functional Interactions within Protein Sequences

    DTIC Science & Technology

    2009-02-23

    22] and Mycobacterium leprae [23], and secondly more closely related pathogenic genomes of Leptospira interrogans serovars Lai [24] and Leptospira... Mycobacterium leprae : a minimal mycobacterial gene set. Genome biology 2001, 2(8):REVIEWS1023. 24. Ren SX, Fu G, Jiang XG, Zeng R, Miao YG, Xu H...operons. Basic evaluation was performed by aligning two pairs of genomes, first relatively distant genomes of Mycobacterium tuberculosis H37Rv [21

  5. LAI estimation in a Mediterranean grassland by in situ radiometric measurements and MODIS satellite data

    NASA Astrophysics Data System (ADS)

    Balzarolo, M.; Arriga, N.; Papale, D.

    2009-04-01

    Leaf Area Index (LAI) is one of a key variables in studying and understanding biogeochemical cycle mechanisms and ecosystem functionalities and, then, one of a main inputs for ecological modeling. Leaf area surface is related to the main interactions between leaves and the atmosphere as water interception, radiation extinction, energy, mass and gas exchange. Therefore LAI reduction, consequently the loss of productivity, is expression of any physiological and biochemical change of plant status due for example to summer water stress in Mediterranean areas. A good knowledge of seasonal trend and spatial variability of LAI can helps not only modelers but also local farmer to manage grasslands in a sustainable way (grazing, harvesting). In situ LAI measurements are often limited to relatively small areas whit a small number of samplings that can be sporadic, destructive and time-consuming. Nowadays an interesting alternative to estimate LAI is provided by a large variety of radiometric sensors (ground, airborne and satellite based) whit several spatial, temporal and spectral resolutions. However, few studies shown the effect of different radiometers set-up on VIs-LAI relationships that are also differently sensible to different ranges of LAI, management and to which method is used for LAI measurements. In this work, we analyzed the relations between several spectral vegetation indexes (VIs) and LAI for the Mediterranean grassland of Amplero, in the Abruzzo Region, Italy. In situ measurements were carried out in 2005 and 2006. Contemporaneously to destructive LAI measurements, radiometric measurements over the grass herbage were made by two different radiometric sensors: by hyperspectral Hand Held ASD spettroradiometer (HYS) field samplings and by broad band measurements (BNR) of incoming and outgoing global (shortwave) solar radiation components and of incident and reflected photosintetically active radiation (PAR). In addition we included in this analysis VIs

  6. ASSESSMENT OF MODIS LAI (W4) IN LOBLOLLY PINE (P. TAEDA) FOREST TYPE, APPOMATTOX, VIRGINIA

    EPA Science Inventory

    The United States Environmental Protection Agency initiated MODIS MODI5A2LAI validation research (2002) in the evergreen needle leaf biome, as defined in the MOD12 classification, in a regional study located in the southeastern United States.

  7. LAI inversion from optical reflectance using a neural network trained with a multiple scattering model

    NASA Technical Reports Server (NTRS)

    Smith, James A.

    1992-01-01

    The inversion of the leaf area index (LAI) canopy parameter from optical spectral reflectance measurements is obtained using a backpropagation artificial neural network trained using input-output pairs generated by a multiple scattering reflectance model. The problem of LAI estimation over sparse canopies (LAI < 1.0) with varying soil reflectance backgrounds is particularly difficult. Standard multiple regression methods applied to canopies within a single homogeneous soil type yield good results but perform unacceptably when applied across soil boundaries, resulting in absolute percentage errors of >1000 percent for low LAI. Minimization methods applied to merit functions constructed from differences between measured reflectances and predicted reflectances using multiple-scattering models are unacceptably sensitive to a good initial guess for the desired parameter. In contrast, the neural network reported generally yields absolute percentage errors of <30 percent when weighting coefficients trained on one soil type were applied to predicted canopy reflectance at a different soil background.

  8. Collection of LAI and FPAR Data Over The Terra Core Sites

    NASA Technical Reports Server (NTRS)

    Myneni, Ranga B.; Knjazihhin, J.; Tian, Y.; Wang, Y.

    2001-01-01

    The objective of our effort was to collect and archive data on LAI (leaf area index) and FPAR (Fraction of Photosynthetically active Radiation absorbed by vegetation) at the EOS Core validation sites as well as to validate and evaluate global fields of LAI and FPAR derived from atmospherically corrected MODIS (Moderate Resolution Imaging Spectrometer) surface reflectance data by comparing these fields with the EOS Core validation data set. The above has been accomplished by: (a) the participation in selected field campaigns within the EOS Validation Program; (b) the processing of the collected data so that suitable comparison between field measurements and the MODIS LAI/FPAR fields can be made; (c) the comparison of the MODAS LAI/FRAM fields with the EOS Terra Core validation data set.

  9. Generation of mammalian host-adapted Leptospira interrogans by cultivation in peritoneal dialysis membrane chamber implantation in rats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leptospira interrogans can infect a myriad of mammalian hosts, including humans (Bharti, Nally et al. 2003, Ko, Goarant et al. 2009). Following acquisition by a suitable host, leptospires disseminate via the bloodstream to multiple tissues, including the kidneys, where they adhere to and colonize th...

  10. A putative regulatory genetic locus modulates virulence in the pathogen Leptospira interrogans.

    PubMed

    Eshghi, Azad; Becam, Jérôme; Lambert, Ambroise; Sismeiro, Odile; Dillies, Marie-Agnès; Jagla, Bernd; Wunder, Elsio A; Ko, Albert I; Coppee, Jean-Yves; Goarant, Cyrille; Picardeau, Mathieu

    2014-06-01

    Limited research has been conducted on the role of transcriptional regulators in relation to virulence in Leptospira interrogans, the etiological agent of leptospirosis. Here, we identify an L. interrogans locus that encodes a sensor protein, an anti-sigma factor antagonist, and two genes encoding proteins of unknown function. Transposon insertion into the gene encoding the sensor protein led to dampened transcription of the other 3 genes in this locus. This lb139 insertion mutant (the lb139(-) mutant) displayed attenuated virulence in the hamster model of infection and reduced motility in vitro. Whole-transcriptome analyses using RNA sequencing revealed the downregulation of 115 genes and the upregulation of 28 genes, with an overrepresentation of gene products functioning in motility and signal transduction and numerous gene products with unknown functions, predicted to be localized to the extracellular space. Another significant finding encompassed suppressed expression of the majority of the genes previously demonstrated to be upregulated at physiological osmolarity, including the sphingomyelinase C precursor Sph2 and LigB. We provide insight into a possible requirement for transcriptional regulation as it relates to leptospiral virulence and suggest various biological processes that are affected due to the loss of native expression of this genetic locus.

  11. A New Global LAI Product and Its Use for Terrestrial Carbon Cycle Estimation

    NASA Astrophysics Data System (ADS)

    Chen, J. M.; Liu, R.; Ju, W.; Liu, Y.

    2014-12-01

    For improving the estimation of the spatio-temporal dynamics of the terrestrial carbon cycle, a new time series of the leaf area index (LAI) is generated for the global land surface at 8 km resolution from 1981 to 2012 by combining AVHRR and MODIS satellite data. This product differs from existing LAI products in the following two aspects: (1) the non-random spatial distribution of leaves with the canopy is considered, and (2) the seasonal variation of the vegetation background is included. The non-randomness of the leaf spatial distribution in the canopy is considered using the second vegetation structural parameter named clumping index (CI), which quantifies the deviation of the leaf spatial distribution from the random case. Using the MODIS Bidirectional Reflectance Distribution Function product, a global map of CI is produced at 500 m resolution. In our LAI algorithm, CI is used to convert the effective LAI obtained from mono-angle remote sensing into the true LAI, otherwise LAI would be considerably underestimated. The vegetation background is soil in crop, grass and shrub but includes soil, grass, moss, and litter in forests. Through processing a large volume of MISR data from 2000 to 2010, monthly red and near-infrared reflectances of the vegetation background is mapped globally at 1 km resolution. This new LAI product has been validated extensively using ground-based LAI measurements distributed globally. In carbon cycle modeling, the use of CI in addition to LAI allows for accurate separation of sunlit and shaded leaves as an important step in terrestrial photosynthesis and respiration modeling. Carbon flux measurements over 100 sites over the globe are used to validate an ecosystem model named Boreal Ecosystem Productivity Simulator (BEPS). The validated model is run globally at 8 km resolution for the period from 1981 to 2012 using the LAI product and other spatial datasets. The modeled results suggest that changes in vegetation structure as quantified

  12. Estimation of Leaf Area Index (LAI) Through the Acquisition of Ground Truth Data in Yosemite National Park

    NASA Astrophysics Data System (ADS)

    Basson, G.; Hawk, A.; Lue, E.; Ottman, D.; Schiffman, B.; Ghosh, M.; Melton, F.; Schmidt, C.; Skiles, J.

    2007-12-01

    Leaf area index (LAI) is an important indicator of ecosystem health. Remote sensing offers the only feasible method of estimating LAI at global and regional scales. Land managers can efficiently monitor changes in vegetation by using NASA data products such as the MODIS LAI 1km product. To increase confidence in use of the MODIS LAI product in Yosemite National Park, we investigated the accuracy of remotely sensed LAI data and created LAI maps using three optical in-situ instruments: the LAI-2000 instrument, digital hemispheric photography (DHP), and the Tracing Radiation and Architecture of Canopies (TRAC) instrument. We compared our in-situ data with three spectral vegetation indices derived from Landsat Thematic Mapper imagery: Reduced Simple Ratio (RSR), Simple Ratio (SR), and Normalized Difference Vegetation Index (NDVI) to produce models which created LAI maps at 30m and 1km resolution. The strongest correlations occurred between DHP LAI values and RSR. Pixel values from the 1km LAI map were then compared to pixel values from a MODIS LAI map. A strong correlation exists between our in-situ data and MODIS LAI values which confirms its accuracy for use by the National Park Service as a decision support tool in Yosemite. The MODIS LAI product is particularly useful because of its high temporal resolution of 1-2 days and can be used to monitor current and future vegetation changes. The model created using the in-situ data can also be applied to Landsat data to provide thirty years of historical LAI values.

  13. Space-time LAI variability in Northern Puglia (Italy) from SPOT VGT data.

    PubMed

    Balacco, Gabriella; Figorito, Benedetto; Tarantino, Eufemia; Gioia, Andrea; Iacobellis, Vito

    2015-07-01

    The vegetation space-time variability during 1999-2010 in the North of the Apulian region (Southern Italy) was analysed using SPOT VEGETATION (VGT) sensor data. Three bands of VEGETATION (RED, NIR and SWIR) were used to implement the vegetation index named reduced simple ratio (RSR) to derive leaf area index (LAI). The monthly average LAI is an indicator of biomass and canopy cover, while the difference between the annual maximum and minimum LAI is an indicator of annual leaf turnover. The space-time distribution of LAI at the catchment scale was analysed over the examined period to detect the consistency of vegetation dynamics in the study area. A diffuse increase of LAI was observed in the examined years that cannot be directly explained only in terms of increasing water availability. Thus, in order to explain such a general behaviour in terms of climatic factors, the analysis was performed upon stratification of land cover classes, focusing on the most widespread species: forest and wheat. An interesting ascending-descending behaviour was observed in the relationship between inter-annual increments of maximum LAI and rainfall, and in particular, a strong negative correlation was found when the rainfall amount in January and February exceeded a critical threshold of about 100 mm.

  14. Salmonella enterica: Survival, Colonization, and Virulence Differences among Serovars

    PubMed Central

    Andino, A.; Hanning, I.

    2015-01-01

    Data indicate that prevalence of specific serovars of Salmonella enterica in human foodborne illness is not correlated with their prevalence in feed. Given that feed is a suboptimal environment for S. enterica, it appears that survival in poultry feed may be an independent factor unrelated to virulence of specific serovars of Salmonella. Additionally, S. enterica serovars appear to have different host specificity and the ability to cause disease in those hosts is also serovar dependent. These differences among the serovars may be related to gene presence or absence and expression levels of those genes. With a better understanding of serovar specificity, mitigation methods can be implemented to control Salmonella at preharvest and postharvest levels. PMID:25664339

  15. Salmonella enterica: survival, colonization, and virulence differences among serovars.

    PubMed

    Andino, A; Hanning, I

    2015-01-01

    Data indicate that prevalence of specific serovars of Salmonella enterica in human foodborne illness is not correlated with their prevalence in feed. Given that feed is a suboptimal environment for S. enterica, it appears that survival in poultry feed may be an independent factor unrelated to virulence of specific serovars of Salmonella. Additionally, S. enterica serovars appear to have different host specificity and the ability to cause disease in those hosts is also serovar dependent. These differences among the serovars may be related to gene presence or absence and expression levels of those genes. With a better understanding of serovar specificity, mitigation methods can be implemented to control Salmonella at preharvest and postharvest levels.

  16. Comparison of the New LEAF Area INDEX (LAI 3G) with the Kazahstan-Wide LEAF Area INDEX DATA SET (GGRS-LAI) over Central ASIA

    NASA Astrophysics Data System (ADS)

    Kappas, M.; Propastin, P.; Degener, J.; Renchin, T.

    2014-12-01

    Long-term global data sets of Leaf Area Index (LAI) are important for monitoring global vegetation dynamics. LAI indicating phenological development of vegetation is an important state variable for modeling land surface processes. The comparison of long-term data sets is based on two recently available data sets both derived from AVHRR time series. The LAI 3g data set introduced by Zaichun Zhu et al. (2013) is developed from the new improved third generation Global Inventory Modeling and Mapping Studies (GIMMS) Normalized Difference Vegetation Index (NDVI3g) and best-quality MODIS LAI data. The second long-term data set is based on the 8 km spatial resolution GIMMS-AVHRR data (GGRS-data set by Propastin et al. 2012). The GGRS-LAI product uses a three-dimensional physical radiative transfer model which establishes relationship between LAI, vegetation fractional cover and given patterns of surface reflectance, view-illumination conditions and optical properties of vegetation. The model incorporates a number of site/region specific parameters, including the vegetation architecture variables such as leaf angle distribution, clumping index, and light extinction coefficient. For the application of the model to Kazakhstan, the vegetation architecture variables were computed at the local (pixel) level based on extensive field surveys of the biophysical properties of vegetation in representative grassland areas of Kazakhstan. The comparison of both long-term data sets will be used to interpret their quality for scientific research in other disciplines. References:Propastin, P., Kappas, M. (2012). Retrieval of coarse-resolution leaf area index over the Republic of Kazakhstan using NOAA AVHRR satellite data and ground measurements," Remote Sensing, vol. 4, no. 1, pp. 220-246. Zaichun Zhu, Jian Bi, Yaozhong Pan, Sangram Ganguly, Alessandro Anav, Liang Xu, Arindam Samanta, Shilong Piao, Ramakrishna R. Nemani and Ranga B. Myneni (2013). Global Data Sets of Vegetation Leaf Area

  17. Linoleic acid isomerase gene FgLAI12 affects sensitivity to salicylic acid, mycelial growth and virulence of Fusarium graminearum

    PubMed Central

    Zhang, Ya-Zhou; Wei, Zhen-Zhen; Liu, Cai-Hong; Chen, Qing; Xu, Bin-Jie; Guo, Zhen-Ru; Cao, Yong-Li; Wang, Yan; Han, Ya-Nan; Chen, Chen; Feng, Xiang; Qiao, Yuan-Yuan; Zong, Lu-Juan; Zheng, Ting; Deng, Mei; Jiang, Qian-Tao; Li, Wei; Zheng, You-Liang; Wei, Yu-Ming; Qi, Peng-Fei

    2017-01-01

    Fusarium graminearum is the major causal agent of fusarium head blight in wheat, a serious disease worldwide. Linoleic acid isomerase (LAI) catalyses the transformation of linoleic acid (LA) to conjugated linoleic acid (CLA), which is beneficial for human health. We characterised a cis-12 LAI gene of F. graminearum (FGSG_02668; FgLAI12), which was downregulated by salicylic acid (SA), a plant defence hormone. Disruption of FgLAI12 in F. graminearum resulted in decreased accumulation of cis-9,trans-11 CLA, enhanced sensitivity to SA, and increased accumulation of LA and SA in wheat spikes during infection. In addition, mycelial growth, accumulation of deoxynivalenol, and pathogenicity in wheat spikes were reduced. Re-introduction of a functional FgLAI12 gene into ΔFgLAI12 recovered the wild-type phenotype. Fluorescent microscopic analysis showed that FgLAI12 protein was usually expressed in the septa zone of conidia and the vacuole of hyphae, but was expressed in the cell membrane of hyphae in response to exogenous LA, which may be an element of LA metabolism during infection by F. graminearum. The cis-12 LAI enzyme encoded by FgLAI12 is critical for fungal response to SA, mycelial growth and virulence in wheat. The gene FgLAI12 is potentially valuable for biotechnological synthesis of cis-9,trans-11 CLA. PMID:28387243

  18. Digital cover photography for estimating leaf area index (LAI) in apple trees using a variable light extinction coefficient.

    PubMed

    Poblete-Echeverría, Carlos; Fuentes, Sigfredo; Ortega-Farias, Samuel; Gonzalez-Talice, Jaime; Yuri, Jose Antonio

    2015-01-28

    Leaf area index (LAI) is one of the key biophysical variables required for crop modeling. Direct LAI measurements are time consuming and difficult to obtain for experimental and commercial fruit orchards. Devices used to estimate LAI have shown considerable errors when compared to ground-truth or destructive measurements, requiring tedious site-specific calibrations. The objective of this study was to test the performance of a modified digital cover photography method to estimate LAI in apple trees using conventional digital photography and instantaneous measurements of incident radiation (Io) and transmitted radiation (I) through the canopy. Leaf area of 40 single apple trees were measured destructively to obtain real leaf area index (LAI(D)), which was compared with LAI estimated by the proposed digital photography method (LAI(M)). Results showed that the LAI(M) was able to estimate LAI(D) with an error of 25% using a constant light extinction coefficient (k = 0.68). However, when k was estimated using an exponential function based on the fraction of foliage cover (f(f)) derived from images, the error was reduced to 18%. Furthermore, when measurements of light intercepted by the canopy (Ic) were used as a proxy value for k, the method presented an error of only 9%. These results have shown that by using a proxy k value, estimated by Ic, helped to increase accuracy of LAI estimates using digital cover images for apple trees with different canopy sizes and under field conditions.

  19. Retrieval of Vertical LAI Profiles Over Tropical Rain Forests using Waveform Lidar at La Selva, Costa Rica

    NASA Technical Reports Server (NTRS)

    Tang, Hao; Dubayah, Ralph; Swatantra, Anu; Hofton, Michelle; Sheldon, Sage; Clark, David B.; Blair, Bryan

    2012-01-01

    This study explores the potential of waveform lidar in mapping the vertical and spatial distributions of leaf area index (LAI) over the tropical rain forest of La Selva Biological Station in Costa Rica. Vertical profiles of LAI were derived at 0.3 m height intervals from the Laser Vegetation Imaging Sensor (LVIS) data using the Geometric Optical and Radiative Transfer (GORT) model. Cumulative LAI profiles obtained from LVIS were validated with data from 55 ground to canopy vertical transects using a modular field tower to destructively sample all vegetation. Our results showed moderate agreement between lidar and field derived LAI (r2=0.42, RMSE=1.91, bias=-0.32), which further improved when differences between lidar and tower footprint scales (r2=0.50, RMSE=1.79, bias=0.27) and distance of field tower from lidar footprint center (r2=0.63, RMSE=1.36, bias=0.0) were accounted for. Next, we mapped the spatial distribution of total LAI across the landscape and analyzed LAI variations over different land cover types. Mean values of total LAI were 1.74, 5.20, 5.41 and 5.62 over open pasture, secondary forests, regeneration forests after selective-logging and old-growth forests respectively. Lastly, we evaluated the sensitivities of our LAI retrieval model to variations in canopy/ground reflectance ratio and to waveform noise such as induced by topographic slopes. We found for both, that the effects were not significant for moderate LAI values (about 4). However model derivations of LAI might be inaccurate in areas of high-slope and high LAI (about 8) if ground return energies are low. This research suggests that large footprint waveform lidar can provide accurate vertical LAI profile estimates that do not saturate even at the high LAI levels in tropical rain forests and may be a useful tool for understanding the light transmittance within these canopies.

  20. [Change of LAI and spectral response for rice under flood and waterlogging stress].

    PubMed

    Xu, Peng; Gu, Xiao-He; Meng, Lu-Min; Qiu, He; Wang, Hui-Fang

    2013-12-01

    In order to provide the foundational theoretical support for flood loss estimation of rice with RS, the change of leaf area index (LAI) and canopy spectral response during four developmental stages and three waterlogging depths were studied, and the LAI estimation model was established with spectra characteristics parameter using regression analysis method. The results show that LAI value decreases as water depth increases in tillering, jointing and heading stages, and LAI value under complete submergence decreased by 36. 36% than CK in jointing stages. "Double-Peak" presented in the canopy first derivative spectra of 680-760 nm where the red edge parameters existed, and the main peak is located in the 724-737 nm with 701 and 718 nm exhibiting secondary peak. With water depth increasing, "Triple-Peak" emerges especially. The red edge position moves to long-wavelength direction in each developmental stage. Blue shift of red edge amplitude and red edge area was detected in tillering, jointing and filling stages, while red shift appeared in heading stage. The relationship between spectra characteristics parameters and LAI were investigated during 4 growth stages, results were not consistently significant at any wavelengths, and the leaf area indices were significantly correlative to the spectra parameters before heading stage, so the spectra parameters before heading stage can be used to estimate the leaf area indices, and a regression model based on parameter D(lambda737)/D(lambda718) was recommended. Therefore the variation range of LAI for rice could response to the stress intensity directly, and the regression model LAI= 3. 138(D(lambda737)/D(lambda718))-0. 806 can precisely estimate the leaf area index under flooding and waterlogging stress.

  1. [A Novel Method of Soil Moisture Content Monitoring by Land Surface Temperature and LAI].

    PubMed

    Gao, Zhong-ling; Zheng, Xiao-po; Sun, Yue-jun; Wang, Jian-hua

    2015-11-01

    Land surface temperature (Ts) is influenced by soil background and vegetation growing conditions, and the combination of Ts and vegetation indices (Vis) can indicate the status of surface soil moisture content (SMC). In this study, Advanced Temperature Vegetation Dryness Index (ATVDI) used for monitoring SMC was proposed on the basis of the simulation results with agricultural climate model CUPID. Previous studies have concluded that Normalized Difference Vegetation Index (NDVI) easily reaches the saturation point, andLeaf Area Index (LAI) was then used instead of NDVI to estimate soil moisture content in the paper. With LAI-Ts scatter diagram established by the simulation results of CUPID model; how Ts varied with LAI and SMC was found. In the case of the identical soil background, the logarithmic relations between Ts and LAI were more accurate than the linear relations included in Temperature Vegetation Dryness Index (TVDI), based on which ATVDI was then developed. LAI-Ts scatter diagram with satellite imagery were necessary for determining the expression of the upper and lower logarithmic curves while ATVDI was used for monitoring SMC. Ts derived from satellite imagery were then transformed to the Ts-value which has the same SMC and the minimum LAI in study area with look-up table. The measured SMC from the field sites in Weihe Plain, Shanxi Province, China, and the products of LAI and Ts (MOD15A2 and MOD11A2, respectively) produced by the image derived from Moderate Resolution Imaging Spectrometer (MODIS) were collected to validate the new method proposed in this study. The validation results shown that ATVDI (R² = 0.62) was accurate enough to monitor SMC, and it achieved better result than TVDI. Moreover, ATVDI-derived result were Ts values with some physical meanings, which made it comparative in different periods. Therefore, ATVDI is a promising method for monitoring SMC in different time-spatial scales in agricultural fields.

  2. Leptospira interrogans at the human-wildlife interface in northern Botswana: a newly identified public health threat.

    PubMed

    Jobbins, S E; Sanderson, C E; Alexander, K A

    2014-03-01

    Leptospirosis is the most widespread zoonosis in the world. In northern Botswana, humans live in close proximity to a diversity of wildlife and peridomestic rodents and may be exposed to a variety of zoonotic pathogens. Little is known regarding the occurrence and epidemiology of L. interrogans in Africa despite the recognized global importance of this zoonotic disease and the threat it poses to public health. In Botswana, banded mongooses (Mungos mungo) live in close proximity to humans across protected and unprotected landscapes and may be a useful sentinel species for assessing the occurrence of zoonotic organisms, such as L. interrogans. We utilized PCR to screen banded mongoose kidneys for leptospiral DNA and identified 41.5% prevalence of renal carriage of L. interrogans (exact binomial 95% CI 27.7-56.7%, n = 41). Renal carriage was also detected in one Selous' mongoose (Paracynictis selousi). This is the first published confirmation of carriage of L. interrogans in either species. This is also the first report of L. interrogans occurrence in northern Botswana and the only report of this organism in a wildlife host in the country. Pathogenic Leptospira are usually transmitted indirectly to humans through soil or water contaminated with infected urine. Other avenues, such as direct contact between humans and wildlife, as well as consumption of mongooses and other wildlife as bushmeat, may pose additional exposure risk and must be considered in public health management of this newly identified zoonotic disease threat. There is a critical need to characterize host species involvement and pathogen transmission dynamics, including human-wildlife interactions that may increase human exposure potential and infection risk. We recommend that public health strategy be modified to include sensitization of medical practitioners to the presence of L. interrogans in the region, the potential for human infection, and implementation of clinical screening. This study

  3. Gene inactivation of a chemotaxis operon in the pathogen Leptospira interrogans.

    PubMed

    Lambert, Ambroise; Wong Ng, Jérôme; Picardeau, Mathieu

    2015-01-01

    Chemotaxis may have an important role in the infection process of pathogenic Leptospira spp.; however, little is known about the regulation of flagellar-based motility in these atypical bacteria. We generated a library of random transposon mutants of the pathogen L. interrogans, which included a mutant with insertion in the first gene of an operon containing the chemotaxis genes cheA, cheW, cheD, cheB, cheY and mcp. The disrupted gene encodes a putative histidine kinase (HK). The HK mutant was motile and virulent, but swarm plate and capillary assays suggested that chemotaxis was reduced in this mutant. Further analysis of bacterial trajectories by videomicroscopy showed that the ability of this mutant to reverse was significantly impaired in comparison to wild-type strain. Our data therefore show that this operon is required for full chemotaxis of Leptospira spp.

  4. An Intercomparison of Passive Terrestrial Remote Sensing Technologies to Derive Lai and Canopy Cover Metrics

    NASA Astrophysics Data System (ADS)

    Woodgate, W. L.

    2012-07-01

    Forest indicators such as Leaf Area Index (LAI) and vegetation cover type are recognised as Essential Climate Variables (ECVs) which support the '…research, modelling, analysis, and capacity-building activities…' requirements of the United Nations Framework Convention on Climate Change. This research compares the use of passive terrestrial remote sensing technologies for LAI and canopy cover metrics. The passive sensors used are the LAI-2200 and Digital Hemispherical Photography (DHP). The research was conducted at a Victorian reference site containing tree species with predominantly erectophile leaf angle distributions, which are significantly under-represented in the literature. The reference site contributes to a network of sites representative of Victorian land systems and is considered to be in good condition. Preliminary results indicate a low correlation (R2=0.46) between the LAI-2200 and DHP. Further comparisons to be conducted include adding a passive CI-110 plant canopy analyser and an active Terrestrial Laser Scanner. The future objective is to scale the in situ data to aerial and satellite remotely sensed datasets. The aerial remotely sensed data include LiDAR flown by a Riegl LMS Q560, and high resolution multispectral and hyperspectral imagery flown by the ASIA Eagle and Hawk system. The in situ data can be utilised for both calibration and validation of the coincident aerial imagery and LiDAR. Finally, the derived datasets are intended for use to validate the global MODIS LAI product.

  5. Analysis and validation of MODIS and ASTER LAI products inverted by PROSAIL

    NASA Astrophysics Data System (ADS)

    Li, Shumin; Li, Hong; Zhou, Liandi; Sun, Danfeng

    2009-06-01

    PROSAIL model is a coupler of PROSPECT leaf optical properties and SAIL canopy reflectance models. Its usage in leaf area index inversion could help avoid the shortages of the experience model. To identify the feasibility of leaf area index (LAI) inversion and the stability of PROSAIL model used in different scales and types of remote sensing data, this paper retrieves LAI of winter wheat in Beijing based on MODIS and ASTER by using the method of PROSAIL model inversion. Firstly, to determine the input parameters of the PROSAIL model, the sensitivity of the five parameters was analyzed. These parameters include chlorophyll a+b concentration, water depth, leaf mesophyll structure parameter, leaf area index, and mean leaf inclination angle. Secondly, the model reproduced the spectral reflectance of the winter wheat, using the determined parameters. Then, inversion was performed to retrieve leaf area index from MODIS and ASTER, and the simulated LAI was validated with field measurements. Because of the distinct scale difference between MODIS and field measurements, ASTER was used to upscale the field measurements by aggregating area-weighted of higher-resolution LAI to acquire LAI of corresponding lower-resolution. The results indicated that there was a high correlation between leaf area index inverted by PROSAIL and actual measurements with a reasonable spatial distribution. Furthermore, it is reliable to use PROSAIL model in remote sensing data with different scales.

  6. Model simulation for sensitivity of hyperspectral indices to LAI, leaf chlorophyll, and internal structure parameter

    NASA Astrophysics Data System (ADS)

    Yuan, Jinguo; Niu, Zheng; Fu, Wenxue

    2007-06-01

    The sensitivity of hyperspectral indices to LAI, chlorophyll contents and leaf internal structure at canopy level are investigated using simulated canopy reflectance dataset, this method can avoid expensive and impractical surface reflectance measurement, providing a theoretical basis for satellite-borne remote sensing. The model employed is PROSAIL that couples leaf reflectance model PROSPECT and canopy radiative transfer model SAIL. Hyperspectral indices used are NDVI, EVI, GI, RI, TVI, SIPI, PRI, TCARI, OSAVI, TCARI/ OSAVI, mNDVI705 and NDWI. Using PROSAIL model, leaf and canopy reflectance under different chlorophyll contents, leaf internal structures, LAI and water contents are first simulated and compared. Then using PROSAIL simulated canopy reflectance data, different hyperspectral indices are calculated, the sensitivity of vegetation indices to LAI and chlorophyll contents is analyzed in detail. And the sensitivity of vegetation indices to leaf internal structure is also analyzed. Results show that relationships between hyperspectral indices and LAI are approximately logarithmic while the relationship between hyperspectral indices and leaf internal structure is linear. EVI and TVI are good indicators to estimate LAI. GI, RI, TCARI, MNDVI 705 can be used to estimate chlorophyll content. N has great influence on hyperspectral indices.

  7. Retrieving Leaf Area Index (LAI) Using Remote Sensing: Theories, Methods and Sensors

    PubMed Central

    Zheng, Guang; Moskal, L. Monika

    2009-01-01

    The ability to accurately and rapidly acquire leaf area index (LAI) is an indispensable component of process-based ecological research facilitating the understanding of gas-vegetation exchange phenomenon at an array of spatial scales from the leaf to the landscape. However, LAI is difficult to directly acquire for large spatial extents due to its time consuming and work intensive nature. Such efforts have been significantly improved by the emergence of optical and active remote sensing techniques. This paper reviews the definitions and theories of LAI measurement with respect to direct and indirect methods. Then, the methodologies for LAI retrieval with regard to the characteristics of a range of remotely sensed datasets are discussed. Remote sensing indirect methods are subdivided into two categories of passive and active remote sensing, which are further categorized as terrestrial, aerial and satellite-born platforms. Due to a wide variety in spatial resolution of remotely sensed data and the requirements of ecological modeling, the scaling issue of LAI is discussed and special consideration is given to extrapolation of measurement to landscape and regional levels. PMID:22574042

  8. Retrieving Leaf Area Index (LAI) Using Remote Sensing: Theories, Methods and Sensors.

    PubMed

    Zheng, Guang; Moskal, L Monika

    2009-01-01

    The ability to accurately and rapidly acquire leaf area index (LAI) is an indispensable component of process-based ecological research facilitating the understanding of gas-vegetation exchange phenomenon at an array of spatial scales from the leaf to the landscape. However, LAI is difficult to directly acquire for large spatial extents due to its time consuming and work intensive nature. Such efforts have been significantly improved by the emergence of optical and active remote sensing techniques. This paper reviews the definitions and theories of LAI measurement with respect to direct and indirect methods. Then, the methodologies for LAI retrieval with regard to the characteristics of a range of remotely sensed datasets are discussed. Remote sensing indirect methods are subdivided into two categories of passive and active remote sensing, which are further categorized as terrestrial, aerial and satellite-born platforms. Due to a wide variety in spatial resolution of remotely sensed data and the requirements of ecological modeling, the scaling issue of LAI is discussed and special consideration is given to extrapolation of measurement to landscape and regional levels.

  9. Recovery of Salmonella enterica serovar Enteritidis from hens initially infected with serovar Kentucky

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovars Enteritidis and Kentucky differ greatly in epidemiology. We wanted to know if the non-pathogenic serotype Kentucky impacted the recovery of the pathogen Enteritidis from chickens. To explore this issue, 4 groups of hens were treated as follows: i) hens were inoculated or...

  10. Molecular differentiation between Salmonella enterica subsp enterica serovar Pullorum and Salmonella enterica subsp enterica serovar Gallinarum

    PubMed Central

    Ribeiro, Simone Alves Mendes; de Paiva, Jaqueline Boldrin; Zotesso, Fábio; Lemos, Manoel Victor Franco; Berchieri Jánior, Ângelo

    2009-01-01

    S. Pullorum (SP) and S. Gallinarum (SG) are very similar. They are the agents of pullorum disease and fowl typhoid, respectively, and the two diseases are responsible for economic losses in poultry production. Although SP and SG are difficult to be differentiated in routine laboratory procedures, the ability to metabolize ornithine is a biochemical test that may be used to achieve this aim. While SP is able to decarboxylate this amino acid, SG is not. However, the isolation of strains showing atypical biochemical behavior has made this differentiation difficult. One of the genes associated with the metabolization of the amino acid ornithine is called speC, and is found in both serovars. The analysis of 21 SP and 15 SG strains by means of PCR did not enable the differentiation of the two serovars, because fragments produced were identical. However, after enzymatic treatment with restriction enzyme Eco RI, the band pattern of each serovar showed to be different, even in samples of atypical biochemical behavior. This fact enabled the standardization of the technique for a quick and safe differentiation of serovars Pullorum and Gallinarum. PMID:24031341

  11. [Monitoring of farmland drought based on LST-LAI spectral feature space].

    PubMed

    Sui, Xin-Xin; Qin, Qi-Ming; Dong, Heng; Wang, Jin-Liang; Meng, Qing-Ye; Liu, Ming-Chao

    2013-01-01

    Farmland drought has the characteristics of wide range and seriously affecting on agricultural production, so real-time dynamic monitored has been a challenging problem. By using MODIS land products, and constructing the spectral space of LST and LAI, the temperature LAI drought index (TLDI) was put forward and validated using ground-measured 0-10 cm averaged soil moisture of Ningxia farmland. The results show that the coefficient of determination (R2) of both them varies from 0.43 to 0.86. Compared to TVDI, the TLDI has higher accuracy for farmland moisture monitoring, and solves the saturation of NDVI during the late development phases of the crop. Furthermore, directly using MODIS land products LST and LAI and avoiding the complicated process of using the original MODIS data provide a new technical process to the regular operation of farmland drought monitoring.

  12. Analyzing C-band SAR polarimetric information for LAI and crop yield estimations

    NASA Astrophysics Data System (ADS)

    Molijn, Ramses A.; Iannini, Lorenzo; Mousivand, Ali; Hanssen, Ramon F.

    2014-10-01

    In this study, space remote sensing data and crop specific information from the ESA-led AgriSAR 2009 campaign are used for studying the profiles of C-band SAR backscatter signals and multispectral-based leaf area index (LAI) over the growth period of canola, pea and wheat. In addition, the correlations between radar backscatter parameters and the crop yields were analyzed, based on extracted statistics of temporal profiles. The results show that the HV backscatter and LAI are correlated differently before and after LAI peak. In addition, the coefficient of determination between peakrelated statistics from polarimetric indicator profiles and yield for pea fields can reach up to 0.68, and for canola and wheat up to 0.47 and 0.5, respectively. HV backscatter and coherence between HH and VV are most.

  13. [Estimation of rice LAI by using NDVI at different spectral bandwidths].

    PubMed

    Wang, Fu-min; Huang, Jing-feng; Tang, Yan-lin; Wang, Xiu-zhen

    2007-11-01

    The canopy hyperspectral reflectance data of rice at its different development stages were collected from field measurement, and the corresponding NDVIs as well as the correlation coefficients of NDVIs and LAI were computed at extending bandwidth of TM red and near-infrared (NIR) spectra. According to the variation characteristics of best fitted R2 with spectral bandwidth, the optimal bandwidth was determined. The results showed that the correlation coefficients of LAI and ND-VI and the maximum R2 of the best fitted functions at different spectral bandwidths had the same variation trend, i.e., decreased with increasing bandwidth when the bandwidth was less than 60 nm. However, when the bandwidth was beyond 60 nm, the maximum R2 somewhat fluctuated due to the effect of NIR. The analysis of R2 variation with bandwidth indicated that 15 nm was the optimal bandwidth for the estimation of rice LAI by using NDVI.

  14. A landscape view of biomass, LAI, and photosynthetic capacity for FIFE

    NASA Technical Reports Server (NTRS)

    Kittel, T. G. F.; Knapp, A. K.; Seastedt, T.; Schimel, D. S.

    1990-01-01

    Canopy properties in the tallgrass prairie are examined in terms of spatial and temporal variability to determine how the variability constrains the ecosystem-atmosphere exchange of H2O, CO2, and momentum. Canopy structure and photosynthetic capacity are examined by measuring soil properties, canopy biomass, and canopy nitrogen along continuous strips. Special attention is given to sites of maximum and minimum biomass where parameters such as leaf-area index (LAI), photosynthetic rate, chemistry, and structures for both burned and unburned areas. The LAI/biomass data and the canopy attributes show that soil properties are shaped by soil-forming and geomorphic processes. The variables that cause the greatest variation in LAI, canopy stratification, and photosynthetic capacity are found to be management (burning and/or grazing) and landscape position.

  15. Genome Sequences of Bacillus thuringiensis Serovar kurstaki Strain BP865 and B. thuringiensis Serovar aizawai Strain HD-133

    PubMed Central

    Jeong, Haeyoung

    2017-01-01

    ABSTRACT We report the draft genome sequences of two insecticidal strains against lepidopteran pests, Bacillus thuringiensis serovar kurstaki strain BP865, an isolate from the South Korean phylloplane, and strain HD-133, a reference strain of B. thuringiensis serovar aizawai. PMID:28153898

  16. Characterizing leaf area index (LAI) and vertical foliage profile (VFP) over the United States

    NASA Astrophysics Data System (ADS)

    Tang, H.; Ganguly, S.; Zhang, G.; Hofton, M. A.; Nelson, R. F.; Dubayah, R.

    2016-01-01

    Leaf area index (LAI) and vertical foliage profile (VFP) are among the important canopy structural variables. Recent advances in lidar remote sensing technology have demonstrated the capability of accurately mapping LAI and VFP over large areas. The primary objective of this study was to derive and validate a LAI and VFP product over the contiguous United States (CONUS) using spaceborne waveform lidar data. This product was derived at the footprint level from the Geoscience Laser Altimeter System (GLAS) using a biophysical model. We validated GLAS-derived LAI and VFP across major forest biomes using airborne waveform lidar. The comparison results showed that GLAS retrievals of total LAI were generally accurate with little bias (r2 = 0.67, bias = -0.13, RMSE = 0.75). The derivations of GLAS retrievals of VFP within layers were not as accurate overall (r2 = 0.36, bias = -0.04, RMSE = 0.26), and these varied as a function of height, increasing from understory to overstory - 0 to 5 m layer: r2 = 0.04, bias = 0.09, RMSE = 0.31; 10 to 15 m layer: r2 = 0.53, bias = -0.08, RMSE = 0.22; and 15 to 20 m layer: r2 = 0.66, bias = -0.05, RMSE = 0.20. Significant relationships were also found between GLAS LAI products and different environmental factors, in particular elevation and annual precipitation. In summary, our results provide a unique insight into vertical canopy structure distribution across North American ecosystems. This data set is a first step towards a baseline of canopy structure needed for evaluating climate and land use induced forest changes at the continental scale in the future, and should help deepen our understanding of the role of vertical canopy structure in terrestrial ecosystem processes across varying scales.

  17. BOREAS RSS-7 Landsat TM LAI IMages of the SSA and NSA

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Chen, Jing; Cihlar, Josef

    2000-01-01

    The BOReal Ecosystem-Atmosphere Study Remote Sensing Science (BOREAS RSS-7) team used Landsat Thematic Mapper (TM) images processed at CCRS to produce images of Leaf Area Index (LAI) for the BOREAS study areas. Two images acquired on 06-Jun and 09-Aug-1991 were used for the SSA, and one image acquired on 09-Jun-1994 was used for the NSA. The LAI images are based on ground measurements and Landsat TM Reduced Simple Ratio (RSR) images. The data are stored in binary image-format files.

  18. Validation of NDVI/LAI Empirical Model to Force a Pasture Growth Model: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Alexandre, C.; Lajoie, G.; Tillard, E.; Salgado, P.

    2016-08-01

    Estimating forage biomass is nowadays essential for a good farm management. To answer to this problem we can use mathematic models that use meteorological, soil, grass data. However, in specifics territories as Reunion Island, they are not efficient. That is why we want to force this kind of model to improve the biomass prediction. The Leaf Area Index (LAI) is one parameter used in growth models. Estimate this parameter from satellite images could a solution to predict better the forage biomass. Preliminary results show a strong relation between LAI and NDVI (Normalized Vegetation Index).

  19. LruA and LruB, Novel Lipoproteins of Pathogenic Leptospira interrogans Associated with Equine Recurrent Uveitis

    PubMed Central

    Verma, Ashutosh; Artiushin, Sergey; Matsunaga, James; Haake, David A.; Timoney, John F.

    2005-01-01

    Recurrent uveitis as a sequela to Leptospira infection is the most common infectious cause of blindness and impaired vision of horses worldwide. Leptospiral proteins expressed during prolonged survival in the eyes of horses with lesions of chronic uveitis were identified by screening a phage library of Leptospira interrogans DNA fragments with eye fluids from uveitic horses. Inserts of reactive phages encoded several known leptospiral proteins and two novel putative lipoproteins, LruA and LruB. LruA was intrinsically labeled during incubation of L. interrogans in medium containing [14C]palmitic acid, confirming that it is a lipoprotein. lruA and lruB were detected by Southern blotting in infectious Leptospira interrogans but not in nonpathogenic Leptospira biflexa. Fractionation data from cultured Leptospira indicate that LruA and LruB are localized in the inner membrane. Uveitic eye fluids contained significantly higher levels of immunoglobulin A (IgA) and IgG specific for each protein than did companion sera, indicating strong local antibody responses. Moreover, LruA- and LruB-specific antisera reacted with equine ocular components, suggesting an immunopathogenic role in leptospiral uveitis. PMID:16239521

  20. Spatial and seasonal variations of leaf area index (LAI) in subtropical secondary forests related to floristic composition and stand characters

    NASA Astrophysics Data System (ADS)

    Zhu, Wenjuan; Xiang, Wenhua; Pan, Qiong; Zeng, Yelin; Ouyang, Shuai; Lei, Pifeng; Deng, Xiangwen; Fang, Xi; Peng, Changhui

    2016-07-01

    Leaf area index (LAI) is an important parameter related to carbon, water, and energy exchange between canopy and atmosphere and is widely applied in process models that simulate production and hydrological cycles in forest ecosystems. However, fine-scale spatial heterogeneity of LAI and its controlling factors have yet to be fully understood in Chinese subtropical forests. We used hemispherical photography to measure LAI values in three subtropical forests (Pinus massoniana-Lithocarpus glaber coniferous and evergreen broadleaved mixed forests, Choerospondias axillaris deciduous broadleaved forests, and L. glaber-Cyclobalanopsis glauca evergreen broadleaved forests) from April 2014 to January 2015. Spatial heterogeneity of LAI and its controlling factors were analysed using geostatistical methods and the generalised additive models (GAMs) respectively. Our results showed that LAI values differed greatly in the three forests and their seasonal variations were consistent with plant phenology. LAI values exhibited strong spatial autocorrelation for the three forests measured in January and for the L. glaber-C. glauca forest in April, July, and October. Obvious patch distribution pattern of LAI values occurred in three forests during the non-growing period and this pattern gradually dwindled in the growing season. Stem number, crown coverage, proportion of evergreen conifer species on basal area basis, proportion of deciduous species on basal area basis, and forest types affected the spatial variations in LAI values in January, while stem number and proportion of deciduous species on basal area basis affected the spatial variations in LAI values in July. Floristic composition, spatial heterogeneity, and seasonal variations should be considered for sampling strategy in indirect LAI measurement and application of LAI to simulate functional processes in subtropical forests.

  1. Generation of Mammalian Host-adapted Leptospira interrogans by Cultivation in Peritoneal Dialysis Membrane Chamber Implantation in Rats.

    PubMed

    Grassmann, André Alex; McBride, Alan John Alexander; Nally, Jarlath E; Caimano, Melissa J

    2015-07-20

    Leptospira interrogans can infect a myriad of mammalian hosts, including humans (Bharti et al., 2003; Ko et al., 2009). Following acquisition by a suitable host, leptospires disseminate via the bloodstream to multiple tissues, including the kidneys, where they adhere to and colonize the proximal convoluted renal tubules (Athanazio et al., 2008). Infected hosts shed large number of spirochetes in their urine and the leptospires can survive in different environmental conditions before transmission to another host. Differential gene expression by Leptospira spp. permits adaption to these new conditions. Here we describe a protocol for the cultivation of Leptospira interrogans within Dialysis Membrane Chambers (DMCs) implanted into the peritoneal cavities of Sprague-Dawley rats (Caimano et al., 2014). This technique was originally developed to study mammalian adaption by the Lyme disease spirochete, Borrelia burgdorferi (Akins et al., 1998; Caimano, 2005). The small pore size (8,000 MWCO) of the dialysis membrane tubing used for this procedure permits access to host nutrients but excludes host antibodies and immune effector cells. Given the physiological and environmental similarities between DMCs and the proximal convoluted renal tubule, we reasoned that the DMC model would be suitable for studying in vivo gene expression by L. interrogans. In a 20 to 30 min procedure, DMCs containing virulent leptospires are surgically-implanted into the rat peritoneal cavity. Nine to 11 days post-implantation, DMCs are explanted and organisms recovered. Typically, a single DMC yields ~10(9) mammalian host-adapted leptospires (Caimano et al., 2014). In addition to providing a facile system for studying the transcriptional and physiologic changes pathogenic L. interrogans undergo within the mammal, the DMC model also provides a rationale basis for selecting new targets for mutagenesis and the identification of novel virulence determinants. Caution: Leptospira interrogans is a BSL-2

  2. [New vegetation index fusing visible-infrared and shortwave infrared spectral feature for winter wheat LAI retrieval].

    PubMed

    Li, Xin-chuan; Bao, Yan-song; Xu, Xin-gang; Jin, Xiu-liang; Zhang, Jing-cheng; Song, Xiao-yu

    2013-09-01

    Considering the great relationships between shortwave infrared (SWIR) and leaf area index (LAI), innovative indices based on water vegetation indices and visible-infrared vegetation indices were presented. In the present work, PROSAIL model was used to study the saturation sensitivity of new vegetation indices to LAI. The estimate models about LAI of winter wheat were built on the basis of the experiment data in 2009 acting as train sample and their precisions were evaluated and tested on the basis of the experiment data in 2008. Ten visible-infrared vegetation indices and five water vegetation indices were used to construct new indices. The result showed that newly developed indices have significant relationships with LAI by numerical simulations and in-situ measurements. In particular, by implementing modified standardized LAI Determining Index (sLAIDI *), all new indices were neither sensitive to water variations nor affected by saturation at high LAI levels. The evaluation models could improve prediction accuracy and have well reliability for LAI retrieval. The result indicated that visible-infrared vegetation indices combined with water index have greater advantage for LAI estimation.

  3. Healthcare cost reductions associated with the use of LAI formulations of antipsychotic medications versus oral among patients with schizophrenia.

    PubMed

    Lin, Jay; Wong, Bruce; Offord, Steve; Mirski, Dario

    2013-07-01

    Real-world medication adherence and healthcare costs of patients with schizophrenia initiating long-acting injectable (LAI) vs. oral antipsychotics were compared. Patients with schizophrenia initiating LAI or oral antipsychotics (index event) were identified from MarketScan Commercial and Medicare claims databases and their medication possession ratios (MPR), pre- and post-index costs for inpatient/outpatient care were compared. Of 3,004 patients, 394 initiated LAI antipsychotics and 2,610 oral antipsychotics. Post-index, the mean MPR was greater for the LAI cohort (0.67 ± 0.34 vs. 0.56 ± 0.35; p < 0.001). Schizophrenia-related hospital costs for LAI users were reduced during the follow-up period in comparison to the pre-index period, but were increased for patients using oral antipsychotics (-$5,981 ± $16,554 vs. 758 ± 14,328, p < 0.001). The change in costs of outpatient care also favored LAI medications ($134 ± 8,280 vs. 658 ± 3,260, p = 0.023). Drug costs of LAI antipsychotics were higher ($4,132 ± 4,533 vs. 2,562 ± 2,714, p < 0.001). Schizophrenia patients initiating LAI antipsychotics incur less healthcare costs in comparison to patients initiating oral antipsychotics.

  4. A novel moisture adjusted vegetation index (MAVI) to reduce background reflectance and topographical effects on LAI retrieval.

    PubMed

    Zhu, Gaolong; Ju, Weimin; Chen, J M; Liu, Yibo

    2014-01-01

    A new moisture adjusted vegetation index (MAVI) is proposed using the red, near infrared, and shortwave infrared (SWIR) reflectance in band-ratio form in this paper. The effectiveness of MAVI in retrieving leaf area index (LAI) is investigated using Landsat-5 data and field LAI measurements in two forest and two grassland areas. The ability of MAVI to retrieve forest LAI under different background conditions is further evaluated using canopy reflectance of Jack Pine and Black Spruce forests simulated by the 4-Scale model. Compared with several commonly used two-band vegetation index, such as normalized difference vegetation index, soil adjusted vegetation index, modified soil adjusted vegetation index, optimized soil adjusted vegetation index, MAVI is a better predictor of LAI, on average, which can explain 70% of variations of LAI in the four study areas. Similar to other SWIR-related three-band vegetation index, such as modified normalized difference vegetation index (MNDVI) and reduced simple ratio (RSR), MAVI is able to reduce the background reflectance effects on forest canopy LAI retrieval. MAVI is more suitable for retrieving LAI than RSR and MNDVI, because it avoids the difficulty in properly determining the maximum and minimum SWIR values required in RSR and MNDVI, which improves the robustness of MAVI in retrieving LAI of different land cover types. Moreover, MAVI is expressed as ratios between different spectral bands, greatly reducing the noise caused by topographical variations, which makes it more suitable for applications in mountainous area.

  5. Spatial Upscaling of Long-term In Situ LAI Measurements from Global Network Sites for Validation of Remotely Sensed Products

    NASA Astrophysics Data System (ADS)

    Xu, B.; Jing, L.; Qinhuo, L.; Zeng, Y.; Yin, G.; Fan, W.; Zhao, J.

    2015-12-01

    Leaf area index (LAI) is a key parameter in terrestrial ecosystem models, and a series of global LAI products have been derived from satellite data. To effectively apply these LAI products, it is necessary to evaluate their accuracy reasonablely. The long-term LAI measurements from the global network sites are an important supplement to the product validation dataset. However, the spatial scale mismatch between the site measurement and the pixel grid hinders the utilization of these measurements in LAI product validation. In this study, a pragmatic approach based on the Bayesian linear regression between long-term LAI measurements and high-resolution images is presented for upscaling the point-scale measurements to the pixel-scale. The algorithm was evaluated using high-resolution LAI reference maps provided by the VALERI project at the Järvselja site and was implemented to upscale the long-term LAI measurements at the global network sites. Results indicate that the spatial scaling algorithm can reduce the root mean square error (RMSE) from 0.42 before upscaling to 0.21 after upscaling compared with the aggregated LAI reference maps at the pixel-scale. Meanwhile, the algorithm shows better reliability and robustness than the ordinary least square (OLS) method for upscaling some LAI measurements acquired at specific dates without high-resolution images. The upscaled LAI measurements were employed to validate three global LAI products, including MODIS, GLASS and GEOV1. Results indicate that (i) GLASS and GEOV1 show consistent temporal profiles over most sites, while MODIS exhibits temporal instability over a few forest sites. The RMSE of seasonality between products and upscaled LAI measurement is 0.25-1.72 for MODIS, 0.17-1.29 for GLASS and 0.36-1.35 for GEOV1 along with different sites. (ii) The uncertainty for products varies over different months. The lowest and highest uncertainty for MODIS are 0.67 in March and 1.53 in August, for GLASS are 0.67 in November

  6. LEAF AREA INDEX (LAI) CHANGE DETECTION ON LOBLOLLY PINE FOREST STANDS WITH COMPLETE UNDERSTORY REMOVAL

    EPA Science Inventory

    The confounding effect of understory vegetation contributions to satellite derived estimates of leaf area index (LAI) was investigated on two loblolly pine forest stands located in the southeastern United States. Previous studies have shown that understory can account from 0-40%...

  7. War Criminals, War Victims: Andersonville, Nuremburg, Hiroshima, My Lai. Crises in World Order.

    ERIC Educational Resources Information Center

    Metcalf, Lawrence, Ed.; And Others

    This pamphlet, intended for senior high school students, examines the complexities of applying international law to questions of individual rights and responsibilities in time of war. Case studies of four actual courtroom trials are presented. Events leading up to the trials (relating to Andersonville, Nuremberg, Hiroshima, and My Lai) are…

  8. Impact of Spatial LAI Heterogeneity on Estimate of Directional Gap Fraction from SPOT-Satellite Data.

    PubMed

    Ma, Lingling; Li, Chuanrong; Tang, Bohui; Tang, Lingli; Bi, Yuyin; Zhou, Beiyan; Li, Zhao-Liang

    2008-06-06

    Directional gap probability or gap fraction is a basic parameter in the optical remote sensing modeling. Although some approaches have been proposed to estimate this gap probability from remotely sensed measurements, few efforts have been made to investigate the scaling effects of this parameter. This paper analyzes the scaling effect through aggregating the high-resolution directional gap probability (pixel size of 20 meters) estimated from leaf area index (LAI) images of VALERI database by means of Beer's law and introduces an extension of clumping index, Ĉ, to compensate the scaling bias. The results show that the scaling effect depends on both the surface heterogeneity and the nonlinearity degree of the retrieved function. Analytical expressions for the scaling bias of gap probability and Ĉ are established in function of the variance of LAI and the mean value of LAI in a coarse pixel. With the VALERI dataset, the study in this paper shows that relative scaling bias of gap probability increases with decreasing spatial resolution for most of land cover types. Large relative biases are found for most of crops sites and a mixed forest site due to their relative large variance of LAI, while very small biases occur over grassland and shrubs sites. As for Ĉ, it varies slowly in the pure forest, grassland and shrubs sites, while more significantly in crops and mixed forest.

  9. LEAF AREA INDEX (LAI) CHANGE DETECTION ANALYSIS ON LOBLOLLY PINE (PINUS TAEDA) FOLLOWING COMPLETE UNDERSTORY REMOVAL

    EPA Science Inventory

    The confounding effect of understory vegetation contributions to satellite-derived estimates of leaf area index (LAI) was investigated on two loblolly pine (Pinus taeda) forest stands located in Virginia and North Carolina. In order to separate NDVI contributions of the dominantc...

  10. A 30+ Year AVHRR LAI and FAPAR Climate Data Record: Algorithm Description, Validation, and Case Study

    NASA Technical Reports Server (NTRS)

    Claverie, Martin; Matthews, Jessica L.; Vermote, Eric F.; Justice, Christopher O.

    2016-01-01

    In- land surface models, which are used to evaluate the role of vegetation in the context ofglobal climate change and variability, LAI and FAPAR play a key role, specifically with respect to thecarbon and water cycles. The AVHRR-based LAIFAPAR dataset offers daily temporal resolution,an improvement over previous products. This climate data record is based on a carefully calibratedand corrected land surface reflectance dataset to provide a high-quality, consistent time-series suitablefor climate studies. It spans from mid-1981 to the present. Further, this operational dataset is availablein near real-time allowing use for monitoring purposes. The algorithm relies on artificial neuralnetworks calibrated using the MODIS LAI/FAPAR dataset. Evaluation based on cross-comparisonwith MODIS products and in situ data show the dataset is consistent and reliable with overalluncertainties of 1.03 and 0.15 for LAI and FAPAR, respectively. However, a clear saturation effect isobserved in the broadleaf forest biomes with high LAI (greater than 4.5) and FAPAR (greater than 0.8) values.

  11. LEAF AREA INDEX (LAI) CHANGE DETECTION ON LOBLOLLY PINE FOREST STANDS WITH COMPLETE UNDERSTORY REMOVAL

    EPA Science Inventory

    The confounding effect of understory vegetation contributions to satellite derived
    estimates of leaf area index (LAI) was investigated on two loblolly pine (Pinus taeda) forest stands located in the southeastern United States. Previous studies have shown that understory can a...

  12. LAI and chlorophyll estimation for a heterogeneous grassland using hyperspectral measurements

    NASA Astrophysics Data System (ADS)

    Darvishzadeh, Roshanak; Skidmore, Andrew; Schlerf, Martin; Atzberger, Clement; Corsi, Fabio; Cho, Moses

    The study shows that leaf area index (LAI), leaf chlorophyll content (LCC) and canopy chlorophyll content (CCC) can be mapped in a heterogeneous Mediterranean grassland from canopy spectral reflectance measurements. Canopy spectral measurements were made in the field using a GER 3700 spectroradiometer, along with concomitant in situ measurements of LAI and LCC. We tested the utility of univariate techniques involving narrow band vegetation indices and the red edge inflection point, as well as multivariate calibration techniques, including stepwise multiple linear regression and partial least squares regression. Among the various investigated models, CCC was estimated with the highest accuracy ( Rcv2=0.74, nRMSE=0.35). All methods failed to estimate LCC ( Rcv2≤0.40), while LAI was estimated with intermediate accuracy ( Rcv2 values ranged from 0.49 to 0.69). Compared with narrow band indices and red edge inflection point, stepwise multiple linear regression generally improved the estimation of LAI. The estimations were further improved when partial least squares regression was used. When a subset of wavelengths was analyzed, it was found that partial least squares regression had reduced the error in the retrieved parameters. The results of the study highlight the significance of multivariate techniques, such as partial least squares regression, rather than univariate methods such as vegetation indices in estimating heterogeneous grass canopy characteristics.

  13. The Laboratory Structure and Task Analysis Inventory (LAI): A Users' Handbook. Technical Report No. 14.

    ERIC Educational Resources Information Center

    Fuhrman, M.; And Others

    The Laboratory Structure and Task Analysis Inventory (LAI) is an instrument designed to facilitate the analysis of laboratory investigations in secondary school science. It yields a quantitative picture of the kinds of activities required of a student in performing laboratory investigations. The report includes guidelines for the use of the…

  14. On Some Aspects of the Semantics and Tonal Behavior of Taiwanese "lai"

    ERIC Educational Resources Information Center

    Lin, Shuang-fu

    1975-01-01

    Explores the semantic distinctions and tonal behaviors of four types of "lai" in Taiwanese. It is concluded that some types cannot be fully understood without reference to the underlying structure, the surface structure being often insufficient for determining the tonal shape of the syllable in utterance. (CLK)

  15. Golden Girl: Mary Lai Reflects as She Marks Her 50th Anniversary.

    ERIC Educational Resources Information Center

    Iwanowski, Jay

    1996-01-01

    The career and administrative style of Mary M. Lai, who celebrates her 50th year as chief financial officer at Long Island University (New York), are discussed. Her perspectives on change in higher education and in the institution during that time, the administrator's role, current challenges for financial officers, and the college environment as…

  16. Daily mapping of Landsat-like LAI and correlation to grape yield

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wine grape quality and quantity are affected by vine growing condition during some critical growing stages. In this paper, MODIS and Landsat were used to map daily LAI in the two Grape Remote sensing Atmospheric Profiling and Evapotranspiration eXperiment (GRAPEX) experiment fields near Lodi, Califo...

  17. [Hyperspectral Estimation of Apple Tree Canopy LAI Based on SVM and RF Regression].

    PubMed

    Han, Zhao-ying; Zhu, Xi-cun; Fang, Xian-yi; Wang, Zhuo-yuan; Wang, Ling; Zhao, Geng-Xing; Jiang, Yuan-mao

    2016-03-01

    Leaf area index (LAI) is the dynamic index of crop population size. Hyperspectral technology can be used to estimate apple canopy LAI rapidly and nondestructively. It can be provide a reference for monitoring the tree growing and yield estimation. The Red Fuji apple trees of full bearing fruit are the researching objects. Ninety apple trees canopies spectral reflectance and LAI values were measured by the ASD Fieldspec3 spectrometer and LAI-2200 in thirty orchards in constant two years in Qixia research area of Shandong Province. The optimal vegetation indices were selected by the method of correlation analysis of the original spectral reflectance and vegetation indices. The models of predicting the LAI were built with the multivariate regression analysis method of support vector machine (SVM) and random forest (RF). The new vegetation indices, GNDVI527, ND-VI676, RVI682, FD-NVI656 and GRVI517 and the previous two main vegetation indices, NDVI670 and NDVI705, are in accordance with LAI. In the RF regression model, the calibration set decision coefficient C-R2 of 0.920 and validation set decision coefficient V-R2 of 0.889 are higher than the SVM regression model by 0.045 and 0.033 respectively. The root mean square error of calibration set C-RMSE of 0.249, the root mean square error validation set V-RMSE of 0.236 are lower than that of the SVM regression model by 0.054 and 0.058 respectively. Relative analysis of calibrating error C-RPD and relative analysis of validation set V-RPD reached 3.363 and 2.520, 0.598 and 0.262, respectively, which were higher than the SVM regression model. The measured and predicted the scatterplot trend line slope of the calibration set and validation set C-S and V-S are close to 1. The estimation result of RF regression model is better than that of the SVM. RF regression model can be used to estimate the LAI of red Fuji apple trees in full fruit period.

  18. Relation of MODIS EVI and LAI across time, vegetation types and hydrological regimes

    NASA Astrophysics Data System (ADS)

    Alexandridis, Thomas; Ovakoglou, George

    2015-04-01

    Estimation of the Leaf Area Index (LAI) of a landscape is considered important to describe the ecosystems activity and is used as an important input parameter in hydrological and biogeochemical models related to water and carbon cycle, desertification risk, etc. The measurement of LAI in the field is a laborious and costly process and is mainly done by indirect methods, such as hemispherical photographs that are processed by specialized software. For this reason there have been several attempts to estimate LAI with multispectral satellite images, using theoretical biomass development models, or empirical equations using vegetation indices and land cover maps. The aim of this work is to study the relation of MODIS EVI and LAI across time, vegetation type, and hydrological regime. This was achieved by studying 120 maps of EVI and LAI which cover a hydrological year and five hydrologically diverse areas: river Nestos in Greece, Queimados catchment in Brazil, Rijnland catchment in The Netherlands, river Tamega in Portugal, and river Umbeluzi in Mozambique. The following Terra MODIS composite datasets were downloaded for the hydrological year 2012-2013: MOD13A2 "Vegetation Indices" and MCD15A2 "LAI and FPAR", as well as the equivalent quality information layers (QA). All the pixels that fall in a vegetation land cover (according to the MERIS GLOBCOVER map) were sampled for the analysis, with the exception of those that fell at the border between two vegetation or other land cover categories, to avoid the influence of mixed pixels. Using linear regression analysis, the relationship between EVI and LAI was identified per date, vegetation type and study area. Results show that vegetation type has the highest influence in the variation of the relationship between EVI and LAI in each study area. The coefficient of determination (R2) is high and statistically significant (ranging from 0.41 to 0.83 in 90% of the cases). When plotting the EVI factor from the regression equation

  19. Purification, crystallization and preliminary crystallographic studies on 2-dehydro-3-deoxygalactarate aldolase from Leptospira interrogans

    PubMed Central

    Li, Xu; Huang, Hua; Song, Xiaomin; Wang, Yanli; Xu, Hang; Teng, Maikun; Gong, Weimin

    2006-01-01

    2-Dehydro-3-deoxygalactarate (DDG) aldolase is a member of the class II aldolase family and plays an important role in the pyruvate-metabolism pathway, catalyzing the reversible aldol cleavage of DDG to pyruvate and tartronic semialdehyde. As it is a potential novel antibiotic target, it is necessary to elucidate the catalytic mechanism of DDG aldolase. To determine the crystal structure, crystals of DDG aldolase from Leptospira interrogans were obtained by the hanging-drop vapour-diffusion method. The crystals diffracted to 2.2 Å resolution using a Cu Kα rotating-anode X-ray source. The crystal belonged to space group C2, with unit-cell parameters a = 293.5, b = 125.6, c = 87.6 Å, β = 100.9°. The V M is calculated to be 2.4 Å3 Da−1, assuming there to be 12 protein molecules in the asymmetric unit. PMID:17142914

  20. High Resolution Simulation of LAI, Carbon and Water Fluxes over France

    NASA Astrophysics Data System (ADS)

    Lafont, Sebastien; Zhao, Yang; Barbu, Alina; Dominique, Carrer; Calvet, Jean Christophe; Peylin, Philippe; Weiss, Marie

    2011-01-01

    The vegetation/land component of GMES is called “Land Monitoring Core service” (LMCS). The geoland2 European project (FP7, 2008-2012) is a demonstrator of the evolution of the LMCS, including the consolidation of prototype services and the test of their operational capacity. The main mission of the land carbon core information service (LC-CIS) of geoland2 is to assess the impact of weather and climate variability on terrestrial biospheric carbon fluxes, in the context of international conventions. The LC-CIS aims at monitoring the global terrestrial carbon fluxes (e.g. to support reporting obligations in the course of the Kyoto Protocol) and setting-up pre-operational infrastructures for providing global products, both in near real time and off-line mode. A multi-model carbon accounting system is developed, coupled with EO data assimilation schemes. Emphasis is put on validation (in-situ data), with downscaling on reference European countries (F, NL, HU). The C-TESSEL and SURFEX modelling platforms (of ECMWF and Météo-France, respectively) are used for production. The ORCHIDEE modelling platform (LSCE) is used for benchmarking and validation purposes. We will present first test of the Geoland2 SURFEX model without data assimilation (Open-loop) over the French domain. We will focus on the simulation of the Leaf Area Index (LAI) and of carbon and water fluxes. The LAI is an important characteristics of the vegetation. It is a good measure of the amount of active vegetation and is linked to the canopy resistance, the water and carbon fluxes between the atmosphere and the vegetation. In this study, we compare 4 different estimations of LAI over France area : two LAI products derived from visible remote sensing and simulated LAI from 2 land surface models. The simulated LAI originates from two land surface models, The ISBA-A-gs model (developed by CNRM) and the ORCHIDEE model (developed by IPSL). The atmospheric forcing for the models is the SAFRAN dataset, a high

  1. Development of a global LAI estimation algorithm for JAXA's new earth observation satellite sensor, GCOM-C/SGLI

    NASA Astrophysics Data System (ADS)

    Ono, Y.; Murakami, H.; Kobayashi, H.; Nasahara, K. N.; Kajiwara, K.; Honda, Y.

    2014-12-01

    Leaf Area Index (LAI) is defined as the one-side green leaf area per unit ground surface area. Global LAI products, such as MOD15 (Terra&Aqua/MODIS) and CYCLOPES (SPOT/VEGETATION) are used for many global terrestrial carbon models. Japan Aerospace eXploration Agency (JAXA) is planning to launch GCOM-C (Global Change Observation Mission-Climate) which carries SGLI (Second-generation GLobal Imager) in the Japanese Fiscal Year 2017. SGLI has the features, such as 17-channel from near ultraviolet to thermal infrared, 250-m spatial resolution, polarization, and multi-angle (nadir and ±45-deg. along-track slant) observation. In the GCOM-C/SGLI land science team, LAI is scheduled to be generated from GCOM-C/SGLI observation data as a standard product (daily 250-m). In extisting algorithms, LAI is estimated by the reverse analysis of vegetation radiative transfer models (RTMs) using multi-spectral and mono-angle observation data. Here, understory layer in vegetation RTMs is assumed by plane parallel (green leaves + soil) which set up arbitrary understroy LAI. However, actual understory consists of various elements, such as green leaves, dead leaves, branches, soil, and snow. Therefore, if understory in vegetation RTMs differs from reality, it will cause an error of LAI to estimate. This report describes an algorithm which estimates LAI in consideration of the influence of understory using GCOM-C/SGLI multi-spectral and multi-angle observation data.

  2. Evaluating the potential of vegetation indices for winter wheat LAI estimation under different fertilization and water conditions

    NASA Astrophysics Data System (ADS)

    Xie, Qiaoyun; Huang, Wenjiang; Dash, Jadunandan; Song, Xiaoyu; Huang, Linsheng; Zhao, Jinling; Wang, Renhong

    2015-12-01

    Leaf area index (LAI) is an important indicator for monitoring crop growth conditions and forecasting grain yield. Many algorithms have been developed for remote estimation of the leaf area index of vegetation, such as using spectral vegetation indices, inversion of radiative transfer models, and supervised learning techniques. Spectral vegetation indices, mathematical combination of reflectance bands, are widely used for LAI estimation due to their computational simplicity and their applications ranged from the leaf scale to the entire globe. However, in many cases, their applicability is limited to specific vegetation types or local conditions due to species specific nature of the relationship used to transfer the vegetation indices to LAI. The overall objective of this study is to investigate the most suitable vegetation index for estimating winter wheat LAI under eight different types of fertilizer and irrigation conditions. Regression models were used to estimate LAI using hyperspectral reflectance data from the Pushbroom Hyperspectral Imager (PHI) and in-situ measurements. Our results showed that, among six vegetation indices investigated, the modified soil-adjusted vegetation index (MSAVI) and the normalized difference vegetation index (NDVI) exhibited strong and significant relationships with LAI, and thus were sensitive across different nitrogen and water treatments. The modified triangular vegetation index (MTVI2) confirmed its potential on crop LAI estimation, although second to MSAVI and NDVI in our study. The enhanced vegetation index (EVI) showed moderate performance. However, the ratio vegetation index (RVI) and the modified simple ratio index (MSR) predicted the least accurate estimations of LAI, exposing the simple band ratio index's weakness under different treatment conditions. The results support the use of vegetation indices for a quick and effective LAI mapping procedure that is suitable for winter wheat under different management practices.

  3. Generating and Evaluation Leaf Area Index (LAI) from MODIS MultiAngle Implementation of Atmospheric Correction (MAIAC) Surface Reflectance Dataset

    NASA Astrophysics Data System (ADS)

    Chen, C.; Park, T.; Yan, K.; Lyapustin, A.; Wang, Y.; CHOI, S.; Yang, B.; Knyazikhin, Y.; Myneni, R. B.

    2015-12-01

    This study generates and evaluates prototype Leaf Area Index (LAI) product based on MODerate resolution Imaging Spectroradiometer's (MODIS) Bidirectional Reflectance Factor (BRF, commonly known as surface reflectance) which is a product of MultiAngle Implementation of Atmospheric Correction (MAIAC) package. LAI is a key parameter of vegetation in characterizing interactions of energy and mass between the Earth's surface and atmosphere. On the other hand, MAIAC BRF is retrieved from a new atmospheric correction algorithm, which has higher spatial resolution and is believed to have more reliable cloud/aerosol detection technique than standard MODIS BRF product. Two main objectives of this study are: 1). Maintaining the radiative transfer theory based LAI algorithm's look up table (LUT) unchanged, to compare LAI product retrieved from different versions of BRF products (MODIS collection 5, collection 6 and MAIAC); 2). To adjust the LUT to resolve LAI's possible systematic discrepancies resulting from atmospheric correction methods within the input BRF other than our LAI algorithm. Before the LUT adjusting, comparing to standard MODIS products shows that MAIAC LAI product will overestimate among herbaceous biome types which have low LAI values, while underestimate among woody biome types which have relatively higher values. Based on the theory of radiative transfer of canopy spectral invariants, two biome and MAIAC specific configurable parameters (Single Scattering Albedo and Uncertainty) in the LUT are adjusted to minimize the inconsistency due to input BRFs. Experiments shows that our new result: 1). has good agreement with field measured data (e.g. DIRECT); 2) is consistent with standard MODIS LAI product.

  4. LaI2@(18,3)SWNT: the unprecedented structure of a LaI2 "Crystal," encapsulated within a single-walled carbon nanotube.

    PubMed

    Friedrichs, Steffi; Kirkland, Angus I; Meyer, Rüdiger R; Sloan, Jeremy; Green, Malcolm L H

    2005-10-01

    The novel crystallization properties of nano-materials represent a great challenge to researchers across all disciplines of materials science. Simple binary solids can be found to adopt unprecedented structures, when confined into nanometer-sized cavities, such as the inner cylindrical bore of single-walled carbon nanotubes (SWNT). Lanthanum iodide was encapsulated within SWNTs and the resulting encapsulation composite was analyzed using energy-dispersive X-ray microanalysis (EDX) and high-resolution transmission electron microscopy (HRTEM) imaging techniques, to reveal a one-dimensional crystal fragment, with the stoichiometry of LaI2, crystallizing in the structure of LaI3 with one third of the iodine positions unoccupied. A complete characterization of the encapsulation composite was achieved using an enhanced image restoration technique, which restores the object wave from a focal series of HRTEM images, providing information about the precise structural data of both filling material and host SWNT, and thereby enabling the identification of the SWNT chirality.

  5. A Highly Stable Plastidic-Type Ferredoxin-NADP(H) Reductase in the Pathogenic Bacterium Leptospira interrogans

    PubMed Central

    Catalano-Dupuy, Daniela L.; Musumeci, Matías A.; López-Rivero, Arleth; Ceccarelli, Eduardo A.

    2011-01-01

    Leptospira interrogans is a bacterium that is capable of infecting animals and humans, and its infection causes leptospirosis with a range of symptoms from flu-like to severe illness and death. Despite being a bacteria, Leptospira interrogans contains a plastidic class ferredoxin-NADP(H) reductase (FNR) with high catalytic efficiency, at difference from the bacterial class FNRs. These flavoenzymes catalyze the electron transfer between NADP(H) and ferredoxins or flavodoxins. The inclusion of a plastidic FNR in Leptospira metabolism and in its parasitic life cycle is not currently understood. Bioinformatic analyses of the available genomic and proteins sequences showed that the presence of this enzyme in nonphotosynthetic bacteria is restricted to the Leptospira genus and that a [4Fe-4S] ferredoxin (LB107) encoded by the Leptospira genome may be the natural substrate of the enzyme. Leptospira FNR (LepFNR) displayed high diaphorase activity using artificial acceptors and functioned as a ferric reductase. LepFNR displayed cytochrome c reductase activity with the Leptospira LB107 ferredoxin with an optimum at pH 6.5. Structural stability analysis demonstrates that LepFNR is one of the most stable FNRs analyzed to date. The persistence of a native folded LepFNR structure was detected in up to 6 M urea, a condition in which the enzyme retains 38% activity. In silico analysis indicates that the high LepFNR stability might be due to robust interactions between the FAD and the NADP+ domains of the protein. The limited bacterial distribution of plastidic class FNRs and the biochemical and structural properties of LepFNR emphasize the uniqueness of this enzyme in the Leptospira metabolism. Our studies show that in L. interrogans a plastidic-type FNR exchanges electrons with a bacterial-type ferredoxin, process which has not been previously observed in nature. PMID:22039544

  6. Genome-Wide Transcriptional Start Site Mapping and sRNA Identification in the Pathogen Leptospira interrogans

    PubMed Central

    Zhukova, Anna; Fernandes, Luis Guilherme; Hugon, Perrine; Pappas, Christopher J.; Sismeiro, Odile; Coppée, Jean-Yves; Becavin, Christophe; Malabat, Christophe; Eshghi, Azad; Zhang, Jun-Jie; Yang, Frank X.; Picardeau, Mathieu

    2017-01-01

    Leptospira are emerging zoonotic pathogens transmitted from animals to humans typically through contaminated environmental sources of water and soil. Regulatory pathways of pathogenic Leptospira spp. underlying the adaptive response to different hosts and environmental conditions remains elusive. In this study, we provide the first global Transcriptional Start Site (TSS) map of a Leptospira species. RNA was obtained from the pathogen Leptospira interrogans grown at 30°C (optimal in vitro temperature) and 37°C (host temperature) and selectively enriched for 5′ ends of native transcripts. A total of 2865 and 2866 primary TSS (pTSS) were predicted in the genome of L. interrogans at 30 and 37°C, respectively. The majority of the pTSSs were located between 0 and 10 nucleotides from the translational start site, suggesting that leaderless transcripts are a common feature of the leptospiral translational landscape. Comparative differential RNA-sequencing (dRNA-seq) analysis revealed conservation of most pTSS at 30 and 37°C. Promoter prediction algorithms allow the identification of the binding sites of the alternative sigma factor sigma 54. However, other motifs were not identified indicating that Leptospira consensus promoter sequences are inherently different from the Escherichia coli model. RNA sequencing also identified 277 and 226 putative small regulatory RNAs (sRNAs) at 30 and 37°C, respectively, including eight validated sRNAs by Northern blots. These results provide the first global view of TSS and the repertoire of sRNAs in L. interrogans. These data will establish a foundation for future experimental work on gene regulation under various environmental conditions including those in the host. PMID:28154810

  7. Temporal Stability of the NDVI-LAI Relationship in a Napa Valley Vineyard

    NASA Technical Reports Server (NTRS)

    Johnson, L. F.

    2003-01-01

    Remotely sensed normalized difference vegetation index (NDVI) values, derived from high-resolution satellite images, were compared with ground measurements of vineyard leaf area index (LAI) periodically during the 2001 growing season. The two variables were strongly related at six ground calibration sites on each of four occasions (r squared = 0.91 to 0.98). Linear regression equations relating the two variables did not significantly differ by observation date, and a single equation accounted for 92 percent of the variance in the combined dataset. Temporal stability of the relationship opens the possibility of transforming NDVI maps to LAI in the absence of repeated ground calibration fieldwork. In order to take advantage of this circumstance, however, steps should be taken to assure temporal consistency in spectral data values comprising the NDVI.

  8. BOREAS RSS-7 Regional LAI and FPAR Images From 10-Day AVHRR-LAC Composites

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Chen, Jing; Cihlar, Josef

    2000-01-01

    The BOReal Ecosystem-Atmosphere Study Remote Sensing Science (BOREAS RSS-7) team collected various data sets to develop and validate an algorithm to allow the retrieval of the spatial distribution of Leaf Area Index (LAI) from remotely sensed images. Advanced Very High Resolution Radiometer (AVHRR) level-4c 10-day composite Normalized Difference Vegetation Index (NDVI) images produced at CCRS were used to produce images of LAI and the Fraction of Photosynthetically Active Radiation (FPAR) absorbed by plant canopies for the three summer IFCs in 1994 across the BOREAS region. The algorithms were developed based on ground measurements and Landsat Thematic Mapper (TM) images. The data are stored in binary image format files.

  9. Evaluation of a canopy reflectance model for LAI estimation through its inversion. [leaf area index

    NASA Technical Reports Server (NTRS)

    Goel, N. S.; Deering, D. W.

    1985-01-01

    A technique for estimating leaf area indices (LAIs) based on bidirectional canopy reflectance (CR) data is applied to three plant canopies: a naturally growing healthy soybean canopy; and a clumped and tufted orchardgrass canopy, respectively. The CR data were collected using a PARABOLA instrument which is capable of acquiring complete sky-and-ground looking hemispheres in 11 seconds. The model fit and LAI estimates were good for the soybean and clumped orchardgrass canopies, but poor for the tufted orchardgrass canopy when the maximum zenith angle was less than 50 percent. It is shown that the biophysical parameter estimation based on CR measurements applied well to homogeneous herbaceous vegetation types, while better CR models are needed to adequately represent discontinuous plant canopies.

  10. Spatiotemporal NDVI, LAI, albedo, and surface temperature dynamics in the southwest of the Brazilian Amazon forest

    NASA Astrophysics Data System (ADS)

    Querino, Carlos Alexandre Santos; Beneditti, Cristina Aparecida; Machado, Nadja Gomes; da Silva, Marcelo José Gama; da Silva Querino, Juliane Kayse Albuquerque; dos Santos Neto, Luiz Alves; Biudes, Marcelo Sacardi

    2016-04-01

    During the last decades, the Amazon rainforest underwent uncontrolled exploitation that modified its environmental variables. The current paper analyzes the spatiotemporal dynamics of the normalized difference vegetation index (NDVI), leaf area index (LAI), and surface albedo, and temperature in two different vegetation covers, preserved and deforested areas. We calculated the remote-sensing products using Landsat 5 TM images obtained during the dry season 1984, 1991, 2000, and 2011 of the central region of the State of Rondônia, Brazil. The results showed a reduction of vegetation indexes NDVI (˜0.70 in 1984 to ˜0.27 in 2011) and LAI (˜1.8 in 1984 to ˜0.3 in 2011), with an increase of surface albedo (0.12 in 1984 to 0.20 in 2011) and temperature (˜24°C in 1984 to 30°C in 2011) as the effect of the rainforest converted in grassland during the study period. No changes in any variables were observed in the protected area. Forest conversion into grassland resulted in a decrease of 69% in NDVI and 110% in LAI and a rise of 59% and 24% in albedo and surface temperature, respectively.

  11. Discovery of a trachyte ignimbrite sequence at Hualālai, Hawaii

    NASA Astrophysics Data System (ADS)

    Shea, Thomas; Owen, Jacqueline

    2016-05-01

    Ignimbrites are common in many intraplate ocean islands but have been missing from the known geological record in Hawaii. During a recent field campaign, the remnants of a trachytic ignimbrite sequence have been discovered at Hualālai volcano, fortuitously preserved from subsequent basaltic lava flow cover. We provide a preliminary description of these deposits, as well as bulk and glass chemical analyses to determine their potential relationship with other nearby trachytes from Pu'u Wa'awa'a (PWW) and Pu'u Anahulu (PA). The results suggest that these ignimbrites are from neither PWW nor PA, but instead may relate to trachytes that are found as maar wallrock blocks some 20 km distant. Therefore, despite being rare overall in Hawaii, the ignimbrites—and more generally trachytes—were probably widespread around Hualālai. Compared to other intraplate ocean islands, the combination of a fast-moving plate, high magma supply, and eruption rates underneath Hawaiian volcanoes may explain the scarcity of ignimbrites preserved at the surface. Their presence at Hualālai could reflect unusual conditions of edifice stress during the transition from shield to post-shield volcanism.

  12. Suicide Prevention in Schizophrenia: Do Long-Acting Injectable Antipsychotics (LAIs) have a role?

    PubMed

    Pompili, Maurizio; Orsolini, Laura; Lamis, Dorian A; Goldsmith, David R; Nardella, Adele; Falcone, Giulia; Corigliano, Valentina; Luciano, Mario; Fiorillo, Andrea

    2017-02-23

    Suicide risk is a major cause of death among patients with schizophrenia. Death by suicide has been reported in approximately 5% of schizophrenia patients although such figure appears an underestimation of the problem. A number of risk factors are routinely reported as associated with suicide risk among these patients, some of which are modifiable by targeted therapeutic strategies. Clozapine is the only compound that gathered evidence as an effective treatment for reducing suicide risk in schizophrenia. Long-Acting Injectable Antipsychotics (LAIs) have a range of advantages in terms of efficacy, safety and tolerability in the treatment of schizophrenia, and one area of interest is whether LAI-treatment may decrease suicidality by indirectly acting on a range of risk factors for suicide specific to schizophrenia patients. This background encouraged the present, review of research pertaining to LAI in relation to modifiable risk factors for suicide in schizophrenia. We viewed our task as gathering, speculatingand critically appraising the available research relevant to the topic, with the aim of formulating a hypothesis to be tested with further research.

  13. Geographic Portability of the Relationships Between LAI, FPAR, and Spectral Vegetation Reflectance

    NASA Astrophysics Data System (ADS)

    Gibbs, H. K.; Washington-Allen, R. A.; King, A. W.; Sale, M. J.

    2002-05-01

    Accurate spatial prediction of biophysical parameters such as leaf area index (LAI) and the fraction of photosynthetically active radiation absorbed by vegetation (FPAR) is critical for many modeling and monitoring applications. Traditional methods that derive these parameters from satellite data require time-consuming and expensive ground measurements to establish relationships with spectral vegetation indices (SVI) or to calibrate bidirectional reflectance distribution function (BRDF) models. Consequently, correlations and model calibrations established for one site are frequently transferred to another site. We assess this geographic transfer and develop potential corrections as part of a multi-laboratory Department of Energy project investigating hydrometeorological processes in the Walnut River Watershed in southeast Kansas. We apply LAI-SVI correlations and BRDF model parameterizations developed for the North America Great Plains and the Konza Prairie Long Term Ecological Research sites to the Walnut River Watershed. Advanced Very High Resolution Radiometer biweekly Normalized Difference Vegetation Index (NDVI) composites from 1999 and 2000 and NDVI derived from Landsat Thematic Mapper scenes from 1999, 2000, and 2001 were used to evaluate and improve the geographic transfer to the watershed. Preliminary analysis indicates that simple corrections using site-specific satellite data to adjust model parameters (e.g., NDVI of bare ground) improve predictions of the ported LAI-SVI relationships and BRDF model calibrations.

  14. Fitness of Salmonella enterica serovar Thompson in the cilantro phyllosphere.

    PubMed

    Brandl, Maria T; Mandrell, Robert E

    2002-07-01

    The epiphytic fitness of Salmonella enterica was assessed on cilantro plants by using a strain of S. enterica serovar Thompson that was linked to an outbreak resulting from cilantro. Salmonella serovar Thompson had the ability to colonize the surface of cilantro leaves, where it was detected by confocal laser scanning microscopy (CLSM) at high densities on the veins and in natural lesions. The population sizes of two common colonizers of plant surfaces, Pantoea agglomerans and Pseudomonas chlororaphis, were 10-fold higher than that of the human pathogen on cilantro incubated at 22 degrees C. However, Salmonella serovar Thompson achieved significantly higher population levels and accounted for a higher proportion of the total culturable bacterial flora on cilantro leaves when the plants were incubated at warm temperatures, such as 30 degrees C, after inoculation, indicating that the higher growth rates exhibited by Salmonella serovar Thompson at warm temperatures may increase the competitiveness of this organism in the phyllosphere. The tolerance of Salmonella serovar Thompson to dry conditions on plants at 60% relative humidity was at least equal to that of P. agglomerans and P. chlororaphis. Moreover, after exposure to low humidity on cilantro, Salmonella serovar Thompson recovered under high humidity to achieve its maximum population size in the cilantro phyllosphere. Visualization by CLSM of green fluorescent protein-tagged Salmonella serovar Thompson and dsRed-tagged P. agglomerans inoculated onto cilantro revealed that the human pathogen and the bacterial epiphyte formed large heterogeneous aggregates on the leaf surface. Our studies support the hypothesis that preharvest contamination of crops by S. enterica plays a role in outbreaks linked to fresh fruits and vegetables.

  15. Complete genome sequence of Leptospira alstonii serovar room 22, strain GWTS#1

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report the complete genome sequence of Leptospira alstonii serovar room 22 strain GWTS#1. This is the first isolate of L. alstonii to be cultured from a mammal, in Western Europe, and represents a new serovar of pathogenic leptospires....

  16. Leptospira interrogans lpxD Homologue Is Required for Thermal Acclimatization and Virulence.

    PubMed

    Eshghi, Azad; Henderson, Jeremy; Trent, M Stephen; Picardeau, Mathieu

    2015-11-01

    Leptospirosis is an emerging disease with an annual occurrence of over 1 million human cases worldwide. Pathogenic Leptospira bacteria are maintained in zoonotic cycles involving a diverse array of mammals, with the capacity to survive outside the host in aquatic environments. Survival in the diverse environments encountered by Leptospira likely requires various adaptive mechanisms. Little is known about Leptospira outer membrane modification systems, which may contribute to the capacity of these bacteria to successfully inhabit and colonize diverse environments and animal hosts. Leptospira bacteria carry two genes annotated as UDP-3-O-[3-hydroxymyristoyl] glucosamine N-acyltransferase genes (la0512 and la4326 [lpxD1 and lpxD2]) that in other bacteria are involved in the early steps of biosynthesis of lipid A, the membrane lipid anchor of lipopolysaccharide. Inactivation of only one of these genes, la0512/lpxD1, imparted sensitivity to the host physiological temperature (37°C) and rendered the bacteria avirulent in an animal infection model. Polymyxin B sensitivity assays revealed compromised outer membrane integrity in the lpxD1 mutant at host physiological temperature, but structural analysis of lipid A in the mutant revealed only minor changes in the lipid A moiety compared to that found in the wild-type strain. In accordance with this, an in trans complementation restored the phenotypes to a level comparable to that of the wild-type strain. These results suggest that the gene annotated as lpxD1 in Leptospira interrogans plays an important role in temperature adaptation and virulence in the animal infection model.

  17. Adipose tissue is the first colonization site of Leptospira interrogans in subcutaneously infected hamsters

    PubMed Central

    Ozuru, Ryo; Saito, Mitsumasa; Kanemaru, Takaaki; Miyahara, Satoshi; Villanueva, Sharon Y. A. M.; Murray, Gerald L.; Adler, Ben; Fujii, Jun; Yoshida, Shin-ichi

    2017-01-01

    Leptospirosis is one of the most widespread zoonoses in the world, and its most severe form in humans, “Weil’s disease,” may lead to jaundice, hemorrhage, renal failure, pulmonary hemorrhage syndrome, and sometimes,fatal multiple organ failure. Although the mechanisms underlying jaundice in leptospirosis have been gradually unraveled, the pathophysiology and distribution of leptospires during the early stage of infection are not well understood. Therefore, we investigated the hamster leptospirosis model, which is the accepted animal model of human Weil’s disease, by using an in vivo imaging system to observe the whole bodies of animals infected with Leptospira interrogans and to identify the colonization and growth sites of the leptospires during the early phase of infection. Hamsters, infected subcutaneously with 104 bioluminescent leptospires, were analyzed by in vivo imaging, organ culture, and microscopy. The results showed that the luminescence from the leptospires spread through each hamster’s body sequentially. The luminescence was first detected at the injection site only, and finally spread to the central abdomen, in the liver area. Additionally, the luminescence observed in the adipose tissue was the earliest detectable compared with the other organs, indicating that the leptospires colonized the adipose tissue at the early stage of leptospirosis. Adipose tissue cultures of the leptospires became positive earlier than the blood cultures. Microscopic analysis revealed that the leptospires colonized the inner walls of the blood vessels in the adipose tissue. In conclusion, this is the first study to report that adipose tissue is an important colonization site for leptospires, as demonstrated by microscopy and culture analyses of adipose tissue in the hamster model of Weil’s disease. PMID:28245231

  18. Leptospira interrogans lpxD Homologue Is Required for Thermal Acclimatization and Virulence

    PubMed Central

    Eshghi, Azad; Henderson, Jeremy; Trent, M. Stephen

    2015-01-01

    Leptospirosis is an emerging disease with an annual occurrence of over 1 million human cases worldwide. Pathogenic Leptospira bacteria are maintained in zoonotic cycles involving a diverse array of mammals, with the capacity to survive outside the host in aquatic environments. Survival in the diverse environments encountered by Leptospira likely requires various adaptive mechanisms. Little is known about Leptospira outer membrane modification systems, which may contribute to the capacity of these bacteria to successfully inhabit and colonize diverse environments and animal hosts. Leptospira bacteria carry two genes annotated as UDP-3-O-[3-hydroxymyristoyl] glucosamine N-acyltransferase genes (la0512 and la4326 [lpxD1 and lpxD2]) that in other bacteria are involved in the early steps of biosynthesis of lipid A, the membrane lipid anchor of lipopolysaccharide. Inactivation of only one of these genes, la0512/lpxD1, imparted sensitivity to the host physiological temperature (37°C) and rendered the bacteria avirulent in an animal infection model. Polymyxin B sensitivity assays revealed compromised outer membrane integrity in the lpxD1 mutant at host physiological temperature, but structural analysis of lipid A in the mutant revealed only minor changes in the lipid A moiety compared to that found in the wild-type strain. In accordance with this, an in trans complementation restored the phenotypes to a level comparable to that of the wild-type strain. These results suggest that the gene annotated as lpxD1 in Leptospira interrogans plays an important role in temperature adaptation and virulence in the animal infection model. PMID:26283339

  19. The Importance of Measurement Errors for Deriving Accurate Reference Leaf Area Index Maps for Validation of Moderate-Resolution Satellite LAI Products

    NASA Technical Reports Server (NTRS)

    Huang, Dong; Yang, Wenze; Tan, Bin; Rautiainen, Miina; Zhang, Ping; Hu, Jiannan; Shabanov, Nikolay V.; Linder, Sune; Knyazikhin, Yuri; Myneni, Ranga B.

    2006-01-01

    The validation of moderate-resolution satellite leaf area index (LAI) products such as those operationally generated from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor data requires reference LAI maps developed from field LAI measurements and fine-resolution satellite data. Errors in field measurements and satellite data determine the accuracy of the reference LAI maps. This paper describes a method by which reference maps of known accuracy can be generated with knowledge of errors in fine-resolution satellite data. The method is demonstrated with data from an international field campaign in a boreal coniferous forest in northern Sweden, and Enhanced Thematic Mapper Plus images. The reference LAI map thus generated is used to assess modifications to the MODIS LAI/fPAR algorithm recently implemented to derive the next generation of the MODIS LAI/fPAR product for this important biome type.

  20. How Universal Is the Relationship Between Remotely Sensed Vegetation Indices (VI) and Crop Leaf Area Index (LAI)?

    NASA Technical Reports Server (NTRS)

    Kang, Yanghui; Ozdogan, Mutlu; Zipper, Samuel C.; Roman, Miguel

    2016-01-01

    Global LAI-VI relationships are statistically significant, crop-specific, and mostly non-linear. This research enables the operationalization of large-area crop modeling and, by extension, has relevance to both fundamental and applied agroecosystem research.

  1. The α-hydroxyketone LAI-1 regulates motility, Lqs-dependent phosphorylation signalling and gene expression of Legionella pneumophila.

    PubMed

    Schell, Ursula; Simon, Sylvia; Sahr, Tobias; Hager, Dominik; Albers, Michael F; Kessler, Aline; Fahrnbauer, Felix; Trauner, Dirk; Hedberg, Christian; Buchrieser, Carmen; Hilbi, Hubert

    2016-02-01

    The causative agent of Legionnaires' disease, Legionella pneumophila, employs the autoinducer compound LAI-1 (3-hydroxypentadecane-4-one) for cell-cell communication. LAI-1 is produced and detected by the Lqs (Legionella quorum sensing) system, comprising the autoinducer synthase LqsA, the sensor kinases LqsS and LqsT, as well as the response regulator LqsR. Lqs-regulated processes include pathogen-host interactions, production of extracellular filaments and natural competence for DNA uptake. Here we show that synthetic LAI-1 promotes the motility of L. pneumophila by signalling through LqsS/LqsT and LqsR. Upon addition of LAI-1, autophosphorylation of LqsS/LqsT by [γ-(32) P]-ATP was inhibited in a dose-dependent manner. In contrast, the Vibrio cholerae autoinducer CAI-1 (3-hydroxytridecane-4-one) promoted the phosphorylation of LqsS (but not LqsT). LAI-1 did neither affect the stability of phospho-LqsS or phospho-LqsT, nor the dephosphorylation by LqsR. Transcriptome analysis of L. pneumophila treated with LAI-1 revealed that the compound positively regulates a number of genes, including the non-coding RNAs rsmY and rsmZ, and negatively regulates the RNA-binding global regulator crsA. Accordingly, LAI-1 controls the switch from the replicative to the transmissive growth phase of L. pneumophila. In summary, the findings indicate that LAI-1 regulates motility and the biphasic life style of L. pneumophila through LqsS- and LqsT-dependent phosphorylation signalling.

  2. Digital Cover Photography for Estimating Leaf Area Index (LAI) in Apple Trees Using a Variable Light Extinction Coefficient

    PubMed Central

    Poblete-Echeverría, Carlos; Fuentes, Sigfredo; Ortega-Farias, Samuel; Gonzalez-Talice, Jaime; Yuri, Jose Antonio

    2015-01-01

    Leaf area index (LAI) is one of the key biophysical variables required for crop modeling. Direct LAI measurements are time consuming and difficult to obtain for experimental and commercial fruit orchards. Devices used to estimate LAI have shown considerable errors when compared to ground-truth or destructive measurements, requiring tedious site-specific calibrations. The objective of this study was to test the performance of a modified digital cover photography method to estimate LAI in apple trees using conventional digital photography and instantaneous measurements of incident radiation (Io) and transmitted radiation (I) through the canopy. Leaf area of 40 single apple trees were measured destructively to obtain real leaf area index (LAID), which was compared with LAI estimated by the proposed digital photography method (LAIM). Results showed that the LAIM was able to estimate LAID with an error of 25% using a constant light extinction coefficient (k = 0.68). However, when k was estimated using an exponential function based on the fraction of foliage cover (ff) derived from images, the error was reduced to 18%. Furthermore, when measurements of light intercepted by the canopy (Ic) were used as a proxy value for k, the method presented an error of only 9%. These results have shown that by using a proxy k value, estimated by Ic, helped to increase accuracy of LAI estimates using digital cover images for apple trees with different canopy sizes and under field conditions. PMID:25635411

  3. Draft genome of the Leptospira interrogans strains, Acegua, RCA, Prea, and Capivara, obtained from wildlife maintenance hosts and infected domestic animals

    PubMed Central

    Kremer, Frederico S; Eslabão, Marcus R; Jorge, Sérgio; Oliveira, Natasha R; Labonde, Julia; Santos, Monize NP; Monte, Leonardo G; Grassmann, André A; Cunha, Carlos EP; Forster, Karine M; Moreno, Luísa Z; Moreno, Andrea M; Campos, Vinicius F; McBride, Alan JA; Pinto, Luciano S; Dellagostin, Odir A

    2016-01-01

    In the present paper, we announce new draft genomes of four Leptospira interrogans strains named Acegua, RCA, Prea, and Capivara. These strains were isolated in the state of Rio Grande do Sul, Brazil, from cattle, dog, Brazilian guinea pig, and capybara, respectively. PMID:27074260

  4. Draft genome of the Leptospira interrogans strains, Acegua, RCA, Prea, and Capivara, obtained from wildlife maintenance hosts and infected domestic animals.

    PubMed

    Kremer, Frederico S; Eslabão, Marcus R; Jorge, Sérgio; Oliveira, Natasha R; Labonde, Julia; Santos, Monize N P; Monte, Leonardo G; Grassmann, André A; Cunha, Carlos E P; Forster, Karine M; Moreno, Luísa Z; Moreno, Andrea M; Campos, Vinicius F; McBride, Alan J A; Pinto, Luciano S; Dellagostin, Odir A

    2016-04-01

    In the present paper, we announce new draft genomes of four Leptospira interrogans strains named Acegua, RCA, Prea, and Capivara. These strains were isolated in the state of Rio Grande do Sul, Brazil, from cattle, dog, Brazilian guinea pig, and capybara, respectively.

  5. Protective Immunity and Reduced Renal Colonization Induced by Vaccines Containing Recombinant Leptospira interrogans Outer Membrane Proteins and Flagellin Adjuvant

    PubMed Central

    Monaris, D.; Sbrogio-Almeida, M. E.; Dib, C. C.; Canhamero, T. A.; Souza, G. O.; Vasconcellos, S. A.; Ferreira, L. C. S.

    2015-01-01

    Leptospirosis is a global zoonotic disease caused by different Leptospira species, such as Leptospira interrogans, that colonize the renal tubules of wild and domestic animals. Thus far, attempts to develop effective leptospirosis vaccines, both for humans and animals, have failed to induce immune responses capable of conferring protection and simultaneously preventing renal colonization. In this study, we evaluated the protective immunity induced by subunit vaccines containing seven different recombinant Leptospira interrogans outer membrane proteins, including the carboxy-terminal portion of the immunoglobulinlike protein A (LigAC) and six novel antigens, combined with aluminum hydroxide (alum) or Salmonella flagellin (FliC) as adjuvants. Hamsters vaccinated with the different formulations elicited high antigen-specific antibody titers. Immunization with LigAC, either with alum or flagellin, conferred protective immunity but did not prevent renal colonization. Similarly, animals immunized with LigAC or LigAC coadministered with six leptospiral proteins with alum adjuvant conferred protection but did not reduce renal colonization. In contrast, immunizing animals with the pool of seven antigens in combination with flagellin conferred protection and significantly reduced renal colonization by the pathogen. The present study emphasizes the relevance of antigen composition and added adjuvant in the efficacy of antileptospirosis subunit vaccines and shows the complex relationship between immune responses and renal colonization by the pathogen. PMID:26108285

  6. Protective Immunity and Reduced Renal Colonization Induced by Vaccines Containing Recombinant Leptospira interrogans Outer Membrane Proteins and Flagellin Adjuvant.

    PubMed

    Monaris, D; Sbrogio-Almeida, M E; Dib, C C; Canhamero, T A; Souza, G O; Vasconcellos, S A; Ferreira, L C S; Abreu, P A E

    2015-08-01

    Leptospirosis is a global zoonotic disease caused by different Leptospira species, such as Leptospira interrogans, that colonize the renal tubules of wild and domestic animals. Thus far, attempts to develop effective leptospirosis vaccines, both for humans and animals, have failed to induce immune responses capable of conferring protection and simultaneously preventing renal colonization. In this study, we evaluated the protective immunity induced by subunit vaccines containing seven different recombinant Leptospira interrogans outer membrane proteins, including the carboxy-terminal portion of the immunoglobulinlike protein A (LigA(C)) and six novel antigens, combined with aluminum hydroxide (alum) or Salmonella flagellin (FliC) as adjuvants. Hamsters vaccinated with the different formulations elicited high antigen-specific antibody titers. Immunization with LigA(C), either with alum or flagellin, conferred protective immunity but did not prevent renal colonization. Similarly, animals immunized with LigA(C) or LigA(C) coadministered with six leptospiral proteins with alum adjuvant conferred protection but did not reduce renal colonization. In contrast, immunizing animals with the pool of seven antigens in combination with flagellin conferred protection and significantly reduced renal colonization by the pathogen. The present study emphasizes the relevance of antigen composition and added adjuvant in the efficacy of antileptospirosis subunit vaccines and shows the complex relationship between immune responses and renal colonization by the pathogen.

  7. Il-10 deficient mice express IFN-γ mRNA and clear Leptospira interrogans from their kidneys more rapidly than normal C57BL/6 mice.

    PubMed

    Devlin, Amy A; Halvorsen, Priya J; Miller, Jennifer C; Laster, Scott M

    2017-02-10

    Leptospira interrogans (L. interrogans), the causative agent of leptospirosis, is a widespread zoonotic spirochete that lives a dual lifestyle. L. interrogans infects mice, rats, and wildlife in a persistent and asymptomatic fashion, while also causing productive and acute infections in other mammals such as humans and hamsters. Infections in humans can be fatal, accompanied by a cytokine storm and shock-like symptoms. Production of IL-10 has been noted in both rodent and human infections which has led a number of investigators to hypothesize that IL-10 plays a role in the pathogenesis of this disease. To test this hypothesis we have compared bacteremia and the cytokine response of normal and IL-10 deficient C57Bl/6 mice following ip infection with L. interrogans. In normal mice bacterial 16s mRNA was detected in both lung and kidney tissues within a day after infection. Levels of 16s mRNA then dropped in both organs with complete elimination from the lung by day 3 but persistence in the kidney for 7days after infection. In contrast, in IL-10 deficient mice, the organism was eliminated more rapidly from the kidney. We found that infection of both control and IL-10 deficient mice produced similar levels of a number of pro-inflammatory cytokine mRNAs. On the other hand, IFN-γ mRNA was only induced in IL-10 deficient mice. These results support the hypothesis that L. interrogans ability to induce IL-10, which in turn prevents production of IFN-γ and inhibits T cell immunity, may contribute to the persistent growth of this microorganism in the murine kidney.

  8. Serovars of Leptospira isolated from dogs and rodents.

    PubMed

    Suepaul, S M; Carrington, C V F; Campbell, M; Borde, G; Adesiyun, A A

    2010-07-01

    We determined the frequency of isolation of Leptospira from dogs and rodents, the serovars of Leptospira, and the clinical, gross and histological manifestations in dogs with leptospirosis in Trinidad. From dogs, samples of urine, blood and kidney were collected while only kidney and blood samples of trapped rodents were used. Isolates were cultured and serotyped using a panel of 23 international serovars and monoclonal antibodies. The risk factors for leptospirosis were also determined in owned dogs using a standard questionnaire. Of a total of 468 animals investigated for Leptospira, 70 (15.0%) were positive, comprising nine (18.0%) of 50 suspected canine leptospirosis cases, seven (3.4%) of 207 stray dogs and 54 (25.6%) of 211 rodents. The observation that rodents have a statistically (P<0.05, chi2) higher frequency of isolation emphasizes the importance of rodents as reservoirs of leptospirosis in the country. Copenhageni was the predominant serovar found in 100.0% (7/7), 33.3% (2/6) and 68.5% (37/54) of isolates from suspected canine leptospirosis cases, stray dogs and rodents, respectively. Serovars Icterohaemorrhagiae and Canicola, the two serovars present in the commercial vaccines used locally, were detected in one (1.5%) and zero (0.0%) isolates respectively of the 67 tested. Data provided suggest that the apparent vaccine failure may be a consequence of the fact that the predominant serovar (Copenhageni) detected in sick, apparently healthy dogs and in rodents is not contained in the vaccines used locally to protect dogs against canine leptospirosis.

  9. Development of a global LAI/ FAPAR estimation algorithm for JAXA's new earth observation satellite,GCOM-C1

    NASA Astrophysics Data System (ADS)

    Ono, Y.; Murakami, H.; Kobayashi, H.; Nasahara, K.; Kajiwara, K.; Honda, Y.

    2013-12-01

    Japan Aerospace eXploration Agency (JAXA) is planning to launch a new earth observation satellite, GCOM-C1 (Global Change Observation Mission 1st-Climate) in the Japanese Fiscal Year 2016. SGLI (Second generation GLobal Imager) is a radiometer, which has 17 channels from near ultraviolet to thermal infrared. Furthermore, it has the features, such as 250m spatial resolution, polarization, and multi-angle observation. In the GCOM-C1 land science team, vegetation index, above ground biomass, LAI (Leaf Area Index), FAPAR (Fraction of Absorbed Photosynthetically Active Radiation), etc. are scheduled to be generated from SGLI data as standard products. These are important in order to estimate terrestrial carbon cycle. In this study, we propose a new LAI and FAPAR estimation algorithm from SGLI data and the proposed algorithm was applied to Terra/ MODIS data. The relation between LAI and BRF (Bidirectional Reflectance Factor) in red and near infrared bands or FAPAR are dependent on crown cover ratio. Therefore, LUT (Look Up Table) of crown cover ratio, LAI and BRF in red and near infrared or FAPAR are created by FLiES which is 3-dimensional radiative transfer model (Kobayashi, H. and H. Iwabuchi (2008), A coupled 1-D atmosphere and 3-D canopy radiative transfer model for canopy reflectance, light environment, and photosynthesis simulation in a heterogeneous landscape, Remote Sensing of Environment, 112, 173-185). First, crown cover ratio is estimated from multiple land surface reflecntace in red and near infrared bands based on LUT of BRF in red and near infrared bands. Next, LAI and FAPAR are estimated from land surface reflectance in red and near infrared band based on estimated crown cover ratio and LUT of BRF in red and near infrared and FAPAR. As a result of applying Terra/ MODIS land surface reflectance product (MOD09), estimated LAI and FAPAR agreed with LAI and FAPAR observed at the AmeriFlux sites.

  10. Specificity of Salmonella Typhimurium strain (ATCC 14028) growth responses to Salmonella serovar-generated spent media.

    PubMed

    Calo, Juliany Rivera; Park, Si Hong; Baker, Christopher A; Ricke, Steven C

    2015-01-01

    Salmonella enterica is one of the most prevalent pathogens responsible for foodborne illness worldwide. Numerous Salmonella serovars have been associated with the consumption of a variety of products, and limiting food-borne illness due to Salmonella serovars is a continuing problem for food producers and public health. The emergence and prevalence of Salmonella serovars has been studied but the predominant serovars have varied somewhat over the years. The aims of this research were to compare the aerobic growth responses of selected predominant foodborne Salmonella serovars, and evaluate how the spent media from different serovars affects the growth of a well-characterized Salmonella Typhimurium strain. Growth responses were similar for most strains in spent media except for S. Typhimurium (ATCC 14028), which exhibited a decrease in growth in the presence of Salmonella Heidelberg (ARI-14) spent media. This research will provide a better understanding of the growth differences among several Salmonella serovars in nutrient limited spent media.

  11. Chu Lai MCAF, Vietnam. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

    DTIC Science & Technology

    1971-03-01

    unlimited distribution of this report to the public at large, or by DTIC to the National Technical Information Service (NTIS). This technical report has...FOM 0-8 5 (01. 1) PREVIOUS EDITION$ OF THIS FORM ARE OSSOLETE AA_ 64 "~ Z* 4 DATA PROCESSING DIVISIONETA+C/USAF SURFACE WINDS 2 AIR WEATER SERVICE /AC...DOCUMENT PROCESSING SHEETDTIC A T 19 70A CHU LAI UWs ETAO DS-&l/017t-~AD A098 605 DATA PROCESSING DIVISION USAF ETAC Air Weather Service ( MAC ) H . Li

  12. Relationship Between LAI and NDVI For IRS LISS and LANDSAT Tm Bands

    NASA Astrophysics Data System (ADS)

    Gupta, R. K.; Prasad, T. S.; Vijayan, D.

    Owing to a highly non-linear relationship between leaf area index and normalized difference vegetation index, polynomials of orders 1 to 4 were fitted to LAI and NDVI for wheat and onion crops using the data collected over their crop growth cycles. It was found that fourth or higher order curve fit better for wheat data whereas polynomials of the order 2 or higher fit the data well for onion. Using the coefficients of the polynomials, NDVI values were computed for LISS-I/II and correlated with actual NDVI values and results were significant at 99% confidence level

  13. BOREAS RSS-4 1994 Southern Study Area Jack Pine LAI and FPAR Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Plummer, Stephen

    2000-01-01

    The RSS-4 team collected several data sets related to leaf, plant, and stand physical, optical, and chemical properties. This data set contains leaf area indices and FPAR measurements that were taken at the three conifer sites in the BOREAS SSA during August 1993 and at the jack pine tower flux and a subset of auxiliary sites during July and August 1994. The measurements were made with LAI-2000 and Ceptometer instruments. The measurements were taken for the purpose of model parameterization and to test empirical relationships that were hypothesized between biophysical parameters and remotely sensed data. The data are stored in tabular ASCII files.

  14. Multiple activities of LigB potentiate virulence of Leptospira interrogans: inhibition of alternative and classical pathways of complement.

    PubMed

    Choy, Henry A

    2012-01-01

    Microbial pathogens acquire the immediate imperative to avoid or counteract the formidable defense of innate immunity as soon as they overcome the initial physical barriers of the host. Many have adopted the strategy of directly disrupting the complement system through the capture of its components, using proteins on the pathogen's surface. In leptospirosis, pathogenic Leptospira spp. are resistant to complement-mediated killing, in contrast to the highly vulnerable non-pathogenic strains. Pathogenic L. interrogans uses LenA/LfhA and LcpA to respectively sequester and commandeer the function of two regulators, factor H and C4BP, which in turn bind C3b or C4b to interrupt the alternative or classical pathways of complement activation. LigB, another surface-proximal protein originally characterized as an adhesin binding multiple host proteins, has other activities suggesting its importance early in infection, including binding extracellular matrix, plasma, and cutaneous repair proteins and inhibiting hemostasis. In this study, we used a recent model of ectopic expression of LigB in the saprophyte, L. biflexa, to test the hypothesis that LigB also interacts with complement proteins C3b and C4b to promote the virulence of L. interrogans. The surface expression of LigB partially rescued the non-pathogen from killing by 5% normal human serum, showing 1.3- to 48-fold greater survival 4 to 6 d following exposure to complement than cultures of the non-expressing parental strain. Recombinant LigB7'-12 comprising the LigB-specific immunoglobulin repeats binds directly to human complement proteins, C3b and C4b, with respective K(d)s of 43±26 nM and 69±18 nM. Repeats 9 to 11, previously shown to contain the binding domain for fibronectin and fibrinogen, are also important in LigB-complement interactions, which interfere with the alternative and classical pathways measured by complement-mediated hemolysis of erythrocytes. Thus, LigB is an adaptable interface for L. interrogans

  15. A data fusion Kalman filter algorithm to estimate leaf area index evolution by using Modis LAI and PROBA-V top of canopy synthesis data

    NASA Astrophysics Data System (ADS)

    Novelli, Antonio

    2016-08-01

    Leaf Area Index (LAI) is essential in ecosystem and agronomic studies, since it measures energy and gas exchanges between vegetation and atmosphere. In the last decades, LAI values have widely been estimated from passive remotely sensed data. Common approaches are based on semi-empirical/statistic techniques or on radiative transfer model inversion. Although the scientific community has been providing several LAI retrieval methods, the estimated results are often affected by noise and measurement uncertainties. The sequential data assimilation theory provides a theoretical framework to combine an imperfect model with incomplete observation data. In this document a data fusion Kalman filter algorithm is proposed in order to estimate the time evolution of LAI by combining MODIS LAI data and PROBA-V surface reflectance data. The reflectance data were linked to LAI by using the Reduced Simple Ratio index. The main working hypotheses were lacking input data necessary for climatic models and canopy reflectance models.

  16. Combined Use of Airborne Lidar and DBInSAR Data to Estimate LAI in Temperate Mixed Forests

    NASA Technical Reports Server (NTRS)

    Peduzzi, Alicia; Wynne, Randolph Hamilton; Thomas, Valerie A.; Nelson, Ross F.; Reis, James J.; Sanford, Mark

    2012-01-01

    The objective of this study was to determine whether leaf area index (LAI) in temperate mixed forests is best estimated using multiple-return airborne laser scanning (lidar) data or dual-band, single-pass interferometric synthetic aperture radar data (from GeoSAR) alone, or both in combination. In situ measurements of LAI were made using the LiCor LAI-2000 Plant Canopy Analyzer on 61 plots (21 hardwood, 36 pine, 4 mixed pine hardwood; stand age ranging from 12-164 years; mean height ranging from 0.4 to 41.2 m) in the Appomattox-Buckingham State Forest, Virginia, USA. Lidar distributional metrics were calculated for all returns and for ten one meter deep crown density slices (a new metric), five above and five below the mode of the vegetation returns for each plot. GeoSAR metrics were calculated from the X-band backscatter coefficients (four looks) as well as both X- and P-band interferometric heights and magnitudes for each plot. Lidar metrics alone explained 69% of the variability in LAI, while GeoSAR metrics alone explained 52%. However, combining the lidar and GeoSAR metrics increased the R2 to 0.77 with a CV-RMSE of 0.42. This study indicates the clear potential for X-band backscatter and interferometric height (both now available from spaceborne sensors), when combined with small-footprint lidar data, to improve LAI estimation in temperate mixed forests.

  17. Spatial Heterogeneity of Leaf Area Index (LAI) and Its Temporal Course on Arable Land: Combining Field Measurements, Remote Sensing and Simulation in a Comprehensive Data Analysis Approach (CDAA).

    PubMed

    Reichenau, Tim G; Korres, Wolfgang; Montzka, Carsten; Fiener, Peter; Wilken, Florian; Stadler, Anja; Waldhoff, Guido; Schneider, Karl

    2016-01-01

    The ratio of leaf area to ground area (leaf area index, LAI) is an important state variable in ecosystem studies since it influences fluxes of matter and energy between the land surface and the atmosphere. As a basis for generating temporally continuous and spatially distributed datasets of LAI, the current study contributes an analysis of its spatial variability and spatial structure. Soil-vegetation-atmosphere fluxes of water, carbon and energy are nonlinearly related to LAI. Therefore, its spatial heterogeneity, i.e., the combination of spatial variability and structure, has an effect on simulations of these fluxes. To assess LAI spatial heterogeneity, we apply a Comprehensive Data Analysis Approach that combines data from remote sensing (5 m resolution) and simulation (150 m resolution) with field measurements and a detailed land use map. Test area is the arable land in the fertile loess plain of the Rur catchment on the Germany-Belgium-Netherlands border. LAI from remote sensing and simulation compares well with field measurements. Based on the simulation results, we describe characteristic crop-specific temporal patterns of LAI spatial variability. By means of these patterns, we explain the complex multimodal frequency distributions of LAI in the remote sensing data. In the test area, variability between agricultural fields is higher than within fields. Therefore, spatial resolutions less than the 5 m of the remote sensing scenes are sufficient to infer LAI spatial variability. Frequency distributions from the simulation agree better with the multimodal distributions from remote sensing than normal distributions do. The spatial structure of LAI in the test area is dominated by a short distance referring to field sizes. Longer distances that refer to soil and weather can only be derived from remote sensing data. Therefore, simulations alone are not sufficient to characterize LAI spatial structure. It can be concluded that a comprehensive picture of LAI spatial

  18. Method for the detection of Salmonella enterica serovar Enteritidis

    DOEpatents

    Agron, Peter G.; Andersen, Gary L.; Walker, Richard L.

    2008-10-28

    Described herein is the identification of a novel Salmonella enterica serovar Enteritidis locus that serves as a marker for DNA-based identification of this bacterium. In addition, three primer pairs derived from this locus that may be used in a nucleotide detection method to detect the presence of the bacterium are also disclosed herein.

  19. High-Throughput Parallel Sequencing to Measure Fitness of Leptospira interrogans Transposon Insertion Mutants during Acute Infection

    PubMed Central

    Matsunaga, James; Haake, David A.

    2016-01-01

    Pathogenic species of Leptospira are the causative agents of leptospirosis, a zoonotic disease that causes mortality and morbidity worldwide. The understanding of the virulence mechanisms of Leptospira spp is still at an early stage due to the limited number of genetic tools available for this microorganism. The development of random transposon mutagenesis in pathogenic strains a decade ago has contributed to the identification of several virulence factors. In this study, we used the transposon sequencing (Tn-Seq) technique, which combines transposon mutagenesis with massive parallel sequencing, to study the in vivo fitness of a pool of Leptospira interrogans mutants. We infected hamsters with a pool of 42 mutants (input pool), which included control mutants with insertions in four genes previously analyzed by virulence testing (loa22, ligB, flaA1, and lic20111) and 23 mutants with disrupted signal transduction genes. We quantified the mutants in different tissues (blood, kidney and liver) at 4 days post-challenge by high-throughput sequencing and compared the frequencies of mutants recovered from tissues to their frequencies in the input pool. Control mutants that were less fit in the Tn-Seq experiment were attenuated for virulence when tested separately in the hamster model of lethal leptospirosis. Control mutants with unaltered fitness were as virulent as the wild-type strain. We identified two mutants with the transposon inserted in the same putative adenylate/guanylate cyclase gene (lic12327) that had reduced in vivo fitness in blood, kidney and liver. Both lic12327 mutants were attenuated for virulence when tested individually in hamsters. Growth of the control mutants and lic12327 mutants in culture medium were similar to that of the wild-type strain. These results demonstrate the feasibility of screening large pools of L. interrogans transposon mutants for those with altered fitness, and potentially attenuated virulence, by transposon sequencing. PMID

  20. High-Throughput Parallel Sequencing to Measure Fitness of Leptospira interrogans Transposon Insertion Mutants during Acute Infection.

    PubMed

    Lourdault, Kristel; Matsunaga, James; Haake, David A

    2016-11-01

    Pathogenic species of Leptospira are the causative agents of leptospirosis, a zoonotic disease that causes mortality and morbidity worldwide. The understanding of the virulence mechanisms of Leptospira spp is still at an early stage due to the limited number of genetic tools available for this microorganism. The development of random transposon mutagenesis in pathogenic strains a decade ago has contributed to the identification of several virulence factors. In this study, we used the transposon sequencing (Tn-Seq) technique, which combines transposon mutagenesis with massive parallel sequencing, to study the in vivo fitness of a pool of Leptospira interrogans mutants. We infected hamsters with a pool of 42 mutants (input pool), which included control mutants with insertions in four genes previously analyzed by virulence testing (loa22, ligB, flaA1, and lic20111) and 23 mutants with disrupted signal transduction genes. We quantified the mutants in different tissues (blood, kidney and liver) at 4 days post-challenge by high-throughput sequencing and compared the frequencies of mutants recovered from tissues to their frequencies in the input pool. Control mutants that were less fit in the Tn-Seq experiment were attenuated for virulence when tested separately in the hamster model of lethal leptospirosis. Control mutants with unaltered fitness were as virulent as the wild-type strain. We identified two mutants with the transposon inserted in the same putative adenylate/guanylate cyclase gene (lic12327) that had reduced in vivo fitness in blood, kidney and liver. Both lic12327 mutants were attenuated for virulence when tested individually in hamsters. Growth of the control mutants and lic12327 mutants in culture medium were similar to that of the wild-type strain. These results demonstrate the feasibility of screening large pools of L. interrogans transposon mutants for those with altered fitness, and potentially attenuated virulence, by transposon sequencing.

  1. A Novel Shigella dysenteriae Serovar Isolated in Canada

    PubMed Central

    Melito, P. L.; Woodward, D. L.; Munro, J.; Walsh, J.; Foster, R.; Tilley, P.; Paccagnella, A.; Isaac-Renton, J.; Ismail, J.; Ng, L. K.

    2005-01-01

    The etiological agent most commonly associated with bacillary dysentery is Shigella. As part of its mandate, the Bacteriology and Enteric Disease Program of Health Canada identifies and serotypes unusual isolates of Shigella received from provincial laboratories of public health. In this report, six unusual isolates from three provinces were analyzed biochemically and serologically using slide and tube agglutinations and molecularly using standard pulsed-filed gel electrophoresis (PFGE), PCR, and PCR-restriction fragment length polymorphism (RFLP) techniques. All six isolates were identical. PFGE analysis grouped these strains; biochemically, they were mannitol negative and consistent with the profile of Shigella. Serologically, these strains produced weak reactions in Shigella dysenteriae serovars 4 and 16 and Escherichia coli O159 and O173 antisera. Molecular serotyping by PCR-RFLP of the rfb gene produced an S. dysenteriae serovar 2/E. coli O112ac pattern. They were positive by PCR for ipaH and ial enteroinvasive genes but negative for all other genes tested. Antiserum was prepared from one of the isolates and tested against Shigella and E. coli reference strains as well as the other isolates. The antiserum reacted with the five remaining isolates and showed cross-reactivity with S. dysenteriae serovars 1, 4, and 16; Shigella flexneri type 3; and E. coli O118, O159, O168, O172, and O173 antigens. Absorbing the sera with E. coli O159 and S. dysenteriae serovar 4 antigen removed all cross-reactions and only slightly reduced the homologous titer. Based on biochemical, molecular, and complete serological analysis, we propose that these six isolates represent a new provisional serovar of S. dysenteriae, type strain BEDP 02-5104. PMID:15695673

  2. Identification of genes associated with survival of salmonellaenterica serovar enteridis in chicken egg albumen

    SciTech Connect

    Clavijo, Raul I.; Loui, Cindy; Andersen, Gary L.; Riley, Lee W.; Lu, Sangwei

    2005-07-13

    Salmonella enterica consists of over 2,000 serovars that aremajor causes of morbidity and mortality associated with contaminatedfood. Despite similarities among serovars of Salmonella enterica, manydemonstrate unique host specificities, epidemiological characteristics,and clinical manifestations. One of the unique epidemiologicalcharacteristics of the serovar Enteritidis is that it is the onlybacterium routinely transmitted to humans through intact chicken eggs.Therefore, Salmonella enterica serovar Enteritidis must be able topersist inside chicken eggs to be transmitted to humans, and its survivalin egg is important for its transmission to the human population. Theability of Salmonella enterica serovar Enteritidis to survive in andtransmit through eggs may have contributed to its drastically increasedprevalence in the 1980s and 1990s. In the present study, usingtransposon-mediated mutagenesis, we have identified genes important forthe association of Salmonella enterica serovar Enteritidis with chickeneggs. Our results indicate that genes involved in cell wall structuraland functional integrity, and nucleic acid and amino acid metabolism areimportant for Salmonella enterica serovar Enteritidis to persist in eggalbumen. Two regions unique toSalmonella enterica serovar Enteritidiswere also identified, one of which enhanced the survival of a Salmonellaenterica serovar Typhimurium isolate in egg albumen. The implication ofour results to the serovar specificity of Salmonella enterica is alsoexplored in the present study.

  3. A live attenuated Salmonella enterica serovar Typhimurium vaccine provides cross-protection against Salmonella serovars to reduce disease severity and pathogen transmission

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A live attenuated Salmonella enterica serovar Typhimurium vaccine was developed to confer broad protection against multiple Salmonella serovars to prevent disease and reduce pathogen colonization and shedding. Two vaccine trials were performed in swine to determine the protection afforded by the vac...

  4. Comparative genomics of Salmonella enterica serovars Derby and Mbandaka, two prevalent serovars associated with different livestock species in the UK

    PubMed Central

    2013-01-01

    Background Despite the frequent isolation of Salmonella enterica sub. enterica serovars Derby and Mbandaka from livestock in the UK and USA little is known about the biological processes maintaining their prevalence. Statistics for Salmonella isolations from livestock production in the UK show that S. Derby is most commonly associated with pigs and turkeys and S. Mbandaka with cattle and chickens. Here we compare the first sequenced genomes of S. Derby and S. Mbandaka as a basis for further analysis of the potential host adaptations that contribute to their distinct host species distributions. Results Comparative functional genomics using the RAST annotation system showed that predominantly mechanisms that relate to metabolite utilisation, in vivo and ex vivo persistence and pathogenesis distinguish S. Derby from S. Mbandaka. Alignment of the genome nucleotide sequences of S. Derby D1 and D2 and S. Mbandaka M1 and M2 with Salmonella pathogenicity islands (SPI) identified unique complements of genes associated with host adaptation. We also describe a new genomic island with a putative role in pathogenesis, SPI-23. SPI-23 is present in several S. enterica serovars, including S. Agona, S. Dublin and S. Gallinarum, it is absent in its entirety from S. Mbandaka. Conclusions We discovered a new 37 Kb genomic island, SPI-23, in the chromosome sequence of S. Derby, encoding 42 ORFS, ten of which are putative TTSS effector proteins. We infer from full-genome synonymous SNP analysis that these two serovars diverged, between 182kya and 625kya coinciding with the divergence of domestic pigs. The differences between the genomes of these serovars suggest they have been exposed to different stresses including, phage, transposons and prolonged externalisation. The two serovars possess distinct complements of metabolic genes; many of which cluster into pathways for catabolism of carbon sources. PMID:23725633

  5. Sources of Uncertainty in the Prediction of LAI / fPAR from MODIS

    NASA Technical Reports Server (NTRS)

    Dungan, Jennifer L.; Ganapol, Barry D.; Brass, James A. (Technical Monitor)

    2002-01-01

    To explicate the sources of uncertainty in the prediction of biophysical variables over space, consider the general equation: where z is a variable with values on some nominal, ordinal, interval or ratio scale; y is a vector of input variables; u is the spatial support of y and z ; x and u are the spatial locations of y and z , respectively; f is a model and B is the vector of the parameters of this model. Any y or z has a value and a spatial extent which is called its support. Viewed in this way, categories of uncertainty are from variable (e.g. measurement), parameter, positional. support and model (e.g. structural) sources. The prediction of Leaf Area Index (LAI) and the fraction of absorbed photosynthetically active radiation (fPAR) are examples of z variables predicted using model(s) as a function of y variables and spatially constant parameters. The MOD15 algorithm is an example of f, called f(sub 1), with parameters including those defined by one of six biome types and solar and view angles. The Leaf Canopy Model (LCM)2, a nested model that combines leaf radiative transfer with a full canopy reflectance model through the phase function, is a simpler though similar radiative transfer approach to f(sub 1). In a previous study, MOD15 and LCM2 gave similar results for the broadleaf forest biome. Differences between these two models can be used to consider the structural uncertainty in prediction results. In an effort to quantify each of the five sources of uncertainty and rank their relative importance for the LAI/fPAR prediction problem, we used recent data for an EOS Core Validation Site in the broadleaf biome with coincident surface reflectance, vegetation index, fPAR and LAI products from the Moderate Resolution Imaging Spectrometer (MODIS). Uncertainty due to support on the input reflectance variable was characterized using Landsat ETM+ data. Input uncertainties were propagated through the LCM2 model and compared with published uncertainties from the MOD15

  6. LAI, FAPAR and FCOVER products derived from AVHRR long time series: principles and evaluation

    NASA Astrophysics Data System (ADS)

    Verger, A.; Baret, F.; Weiss, M.; Lacaze, R.; Makhmara, H.; Pacholczyk, P.; Smets, B.; Kandasamy, S.; Vermote, E.

    2012-04-01

    Continuous and long term global monitoring of the terrestrial biosphere has draught an intense interest in the recent years in the context of climate and global change. Developing methodologies for generating historical data records from data collected with different satellite sensors over the past three decades by taking benefits from the improvements identified in the processing of the new generation sensors is a new central issue in remote sensing community. In this context, the Bio-geophysical Parameters (BioPar) service within Geoland2 project (http://www.geoland2.eu) aims at developing pre-operational infrastructures for providing global land products both in near real time and off-line mode with long time series. In this contribution, we describe the principles of the GEOLAND algorithm for generating long term datasets of three key biophysical variables, leaf area index (LAI), Fraction of Absorbed Photosynthetic Active Radiation (FAPAR) and cover fraction (FCOVER), that play a key role in several processes, including photosynthesis, respiration and transpiration. LAI, FAPAR and FCOVER are produced globally from AVHRR Long Term Data Record (LTDR) for the 1981-2000 period at 0.05° spatial resolution and 10 days temporal sampling frequency. The proposed algorithm aims to ensure robustness of the derived long time series and consistency with the ones developed in the recent years, and particularly with GEOLAND products derived from VEGETATION sensor. The approach is based on the capacity of neural networks to learn a particular biophysical product (GEOLAND) from reflectances from another sensor (AVHRR normalized reflectances in the red and near infrared bands). Outliers due to possible cloud contamination or residual atmospheric correction are iteratively eliminated. Prior information based on the climatology is used to get more robust estimates. A specific gap filing and smoothing procedure was applied to generate continuous and smooth time series of decadal

  7. Live imaging of bioluminescent leptospira interrogans in mice reveals renal colonization as a stealth escape from the blood defenses and antibiotics.

    PubMed

    Ratet, Gwenn; Veyrier, Frédéric J; Fanton d'Andon, Martine; Kammerscheit, Xavier; Nicola, Marie-Anne; Picardeau, Mathieu; Boneca, Ivo G; Werts, Catherine

    2014-12-01

    Leptospira (L.) interrogans are bacteria responsible for a worldwide reemerging zoonosis. Some animals asymptomatically carry L. interrogans in their kidneys and excrete bacteria in their urine, which contaminates the environment. Humans are infected through skin contact with leptospires and develop mild to severe leptospirosis. Previous attempts to construct fluorescent or bioluminescent leptospires, which would permit in vivo visualization and investigation of host defense mechanisms during infection, have been unsuccessful. Using a firefly luciferase cassette and random transposition tools, we constructed bioluminescent chromosomal transformants in saprophytic and pathogenic leptospires. The kinetics of leptospiral dissemination in mice, after intraperitoneal inoculation with a pathogenic transformant, was tracked by bioluminescence using live imaging. For infective doses of 106 to 107 bacteria, we observed dissemination and exponential growth of leptospires in the blood, followed by apparent clearance of bacteria. However, with 2×108 bacteria, the septicemia led to the death of mice within 3 days post-infection. In surviving mice, one week after infection, pathogenic leptospires reemerged only in the kidneys, where they multiplied and reached a steady state, leading to a sustained chronic renal infection. These experiments reveal that a fraction of the leptospiral population escapes the potent blood defense, and colonizes a defined number of niches in the kidneys, proportional to the infective dose. Antibiotic treatments failed to eradicate leptospires that colonized the kidneys, although they were effective against L. interrogans if administered before or early after infection. To conclude, mice infected with bioluminescent L. interrogans proved to be a novel model to study both acute and chronic leptospirosis, and revealed that, in the kidneys, leptospires are protected from antibiotics. These bioluminescent leptospires represent a powerful new tool to

  8. Emergence of novel Leptospira serovars: a need for adjusting vaccination policies for dogs?

    PubMed

    Arent, Z J; Andrews, S; Adamama-Moraitou, K; Gilmore, C; Pardali, D; Ellis, W A

    2013-06-01

    A total of 855 sera from dogs in Greece were tested for antibodies to strains belonging to the Pomona, Grippotyphosa and Australis serogroups of Leptospira to assess exposure levels to these serogroups, possible associations with clinical disease and to evaluate whether these findings support the inclusion of additional serovars in dog vaccines. Antibodies were detected in 110 (12·9%) dogs. The highest seroprevalence (4·9%) was to the proposed novel serovar Altodouro belonging to the Pomona serogroup. This serovar also showed a statistically significant association with clinical disease. Serovar Bratislava antibodies were found in 3·4% of sera. Consideration should be given to the inclusion of serovars belonging to the Pomona serogroup and serovar Bratislava in future dog vaccines for the Greek market.

  9. Exact steady state manifold of a boundary driven spin-1 Lai-Sutherland chain

    NASA Astrophysics Data System (ADS)

    Ilievski, Enej; Prosen, Tomaž

    2014-05-01

    We present an explicit construction of a family of steady state density matrices for an open integrable spin-1 chain with bilinear and biquadratic interactions, also known as the Lai-Sutherland model, driven far from equilibrium by means of two oppositely polarizing Markovian dissipation channels localized at the boundary. The steady state solution exhibits n+1 fold degeneracy, for a chain of length n, due to existence of (strong) Liouvillian U(1) symmetry. The latter can be exploited to introduce a chemical potential and define a grand canonical nonequilibrium steady state ensemble. The matrix product form of the solution entails an infinitely-dimensional representation of a non-trivial Lie algebra (semidirect product of sl2 and a non-nilpotent radical) and hints to a novel Yang-Baxter integrability structure.

  10. Emplacement of the most recent lava flows on Hualālai Volcano, Hawai'i

    USGS Publications Warehouse

    Kauahikaua, James P.; Cashman, K.; Clague, D.; Champion, D.; Hagstrum, J.

    2002-01-01

    A detailed field and petrologic study of the ca. 1800 a.d. flows at Hualālai Volcano documents at least two eruptive episodes, the Hu‘ehu‘e flow field ending in 1801, and the Ka‘ūpūlehu flow several decades earlier. The morphology and stratigraphy of the Ka‘ūpūlehu flow require an emplacement duration of several days to weeks. Based on a comparison with recent eruptive activity at Mauna Loa volcano, the eruption cannot have occurred at the anomalously high rate (104–105 m3/s) proposed by previous workers. The hummocky flow surface of the later phase of the Hu‘ehu‘e eruption suggests a duration of months, based on a comparison with recent eruptive activity at Kīlauea Volcano. Although none of the ca. 1800 flows show evidence for extraordinarily fast emplacement or unusual fluid rheologies, both flows show unusual features. The abundant xenoliths for which the Ka‘ūpūlehu flow is famous were transported in numerous episodes of deposition and remobilization, during which they eroded the channel systems through which they traveled. Lava transport in proximal and medial regions of both flow fields was probably through lava tubes, as evidenced by preserved tubes and by the prevalence of pāhoehoe-lined channels that require thermally efficient transport of lava over great distances. Both flows also show abundant evidence for re-occupation of older cones and lava tubes, a characteristic that may typify infrequent eruptions of older volcanic systems. Although lava flows from Hualālai Volcano do not show anomalous eruptive behavior, they pose a substantial hazard for coastal communities of Kona.

  11. Draft Genome Sequences of Salmonella enterica subsp. enterica Serovars Typhimurium and Nottingham Isolated from Food Products

    PubMed Central

    Zheng, Jie; Ayers, Sherry; Melka, David C.; Curry, Phillip E.; Payne, Justin S.; Laasri, Anna; Wang, Charles; Hammack, Thomas S.; Brown, Eric W.

    2016-01-01

    A quantitative real-time PCR (qPCR) designed to detect Salmonella enterica subsp. enterica serovar Enteritidis, targeting the sdf gene, generated positive results for S. enterica subsp. enterica serovar Typhimurium (CFSAN033950) and S. enterica subsp. enterica serovar Nottingham (CFSAN006803) isolated from food samples. Both strains show pulsed-field gel electrophoresis (PFGE) patterns distinct from those of S. Enteritidis. Here, we report the genome sequences of these two strains. PMID:27445384

  12. EPIC-Simulated and MODIS-Derived Leaf Area Index (LAI) Comparisons Across mMltiple Spatial Scales RSAD Oral Poster based session

    EPA Science Inventory

    Leaf Area Index (LAI) is an important parameter in assessing vegetation structure for characterizing forest canopies over large areas at broad spatial scales using satellite remote sensing data. However, satellite-derived LAI products can be limited by obstructed atmospheric cond...

  13. Intercomparison and validation of MODIS and GLASS leaf area index (LAI) products over mountain areas: A case study in southwestern China

    NASA Astrophysics Data System (ADS)

    Jin, Huaan; Li, Ainong; Bian, Jinhu; Nan, Xi; Zhao, Wei; Zhang, Zhengjian; Yin, Gaofei

    2017-03-01

    The validation study of leaf area index (LAI) products over rugged surfaces not only gives additional insights into data quality of LAI products, but deepens understanding of uncertainties regarding land surface process models depended on LAI data over complex terrain. This study evaluated the performance of MODIS and GLASS LAI products using the intercomparison and direct validation methods over southwestern China. The spatio-temporal consistencies, such as the spatial distributions of LAI products and their statistical relationship as a function of topographic indices, time, and vegetation types, respectively, were investigated through intercomparison between MODIS and GLASS products during the period 2011-2013. The accuracies and change ranges of these two products were evaluated against available LAI reference maps over 10 sampling regions which standed for typical vegetation types and topographic gradients in southwestern China. The results show that GLASS LAI exhibits higher percentage of good quality data (i.e. successful retrievals) and smoother temporal profiles than MODIS LAI. The percentage of successful retrievals for MODIS and GLASS is vulnerable to topographic indices, especially to relief amplitude. Besides, the two products do not capture seasonal dynamics of crop, especially in spring over heterogeneously hilly regions. The yearly mean LAI differences between MODIS and GLASS are within ±0.5 for 64.70% of the total retrieval pixels over southwestern China. The spatial distribution of mean differences and temporal profiles of these two products are inclined to be dominated by vegetation types other than topographic indices. The spatial and temporal consistency of these two products is good over most area of grasses/cereal crops; however, it is poor for evergreen broadleaf forest. MODIS presents more reliable change range of LAI than GLASS through comparison with fine resolution reference maps over most of sampling regions. The accuracies of direct

  14. Leaf Area Index (LAI) in different type of agroforestry systems based on hemispherical photographs in Cidanau Watershed

    NASA Astrophysics Data System (ADS)

    Nur Khairiah, Rahmi; Setiawan, Yudi; Budi Prasetyo, Lilik; Ayu Permatasari, Prita

    2017-01-01

    Ecological functions of agroforestry systems have perceived benefit to people around Cidanau Watershed, especially in the protection of water quality. The main causes of the problems encountered in the Cidanau Watershed are associated with the human factors, especially encroachment and conversion of forest into farmland. The encroachment has made most forest in Cidanau Watershed become bare land. To preserve the ecological function of agroforestry systems in Cidanau Watershed, monitoring of the condition of the vegetation canopy in agroforestry systems is really needed. High intensity thinning of crown density due to deforestation can change stand leaf area index dramatically. By knowing LAI, we can assess the condition of the vegetation canopy in agroforestry systems. LAI in this research was obtained from Hemispherical Photographs analysis using the threshold method in HemiView Canopy Analysis Software. Our research results indicate that there are six types of agroforestry in Cidanau Watershed i.e. Sengon Agroforestry, Clove Agroforestry, Melinjo Agroforestry, Chocolate Agroforestry, Coffee Agroforestry, and Complex Agroforestry. Several factors potentially contribute to variations in the value of LAI in different types of agroforestry. The simple assumptions about differences ranges of LAI values on six types of agroforestry is closely related to leaf area and plant population density.

  15. Aspartic Peptide Hydrolases in Salmonella enterica Serovar Typhimurium

    PubMed Central

    Larsen, Rachel A.; Knox, Tina M.; Miller, Charles G.

    2001-01-01

    Two well-characterized enzymes in Salmonella enterica serovar Typhimurium and Escherichia coli are able to hydrolyze N-terminal aspartyl (Asp) dipeptides: peptidase B, a broad-specificity aminopeptidase, and peptidase E, an Asp-specific dipeptidase. A serovar Typhimurium strain lacking both of these enzymes, however, can still utilize most N-terminal Asp dipeptides as sources of amino acids, and extracts of such a strain contain additional enzymatic activities able to hydrolyze Asp dipeptides. Here we report two such activities from extracts of pepB pepE mutant strains of serovar Typhimurium identified by their ability to hydrolyze Asp-Leu. Although each of these activities hydrolyzes Asp-Leu at a measurable rate, the preferred substrates for both are N-terminal isoAsp peptides. One of the activities is a previously characterized isoAsp dipeptidase from E. coli, the product of the iadA gene. The other is the product of the serovar Typhimurium homolog of E. coli ybiK, a gene of previously unknown function. This gene product is a member of the N-terminal nucleophile structural family of amidohydrolases. Like most other members of this family, the mature enzyme is generated from a precursor protein by proteolytic cleavage and the active enzyme is a heterotetramer. Based on its ability to hydrolyze an N-terminal isoAsp tripeptide as well as isoAsp dipeptides, the enzyme appears to be an isoAsp aminopeptidase, and we propose that the gene encoding it be designated iaaA (isoAsp aminopeptidase). A strain lacking both IadA and IaaA in addition to peptidase B and peptidase E has been constructed. This strain utilizes Asp-Leu as a leucine source, and extracts of this strain contain at least one additional, as-yet-uncharacterized, peptidase able to cleave Asp dipeptides. PMID:11325937

  16. Aspartic peptide hydrolases in Salmonella enterica serovar typhimurium.

    PubMed

    Larsen, R A; Knox, T M; Miller, C G

    2001-05-01

    Two well-characterized enzymes in Salmonella enterica serovar Typhimurium and Escherichia coli are able to hydrolyze N-terminal aspartyl (Asp) dipeptides: peptidase B, a broad-specificity aminopeptidase, and peptidase E, an Asp-specific dipeptidase. A serovar Typhimurium strain lacking both of these enzymes, however, can still utilize most N-terminal Asp dipeptides as sources of amino acids, and extracts of such a strain contain additional enzymatic activities able to hydrolyze Asp dipeptides. Here we report two such activities from extracts of pepB pepE mutant strains of serovar Typhimurium identified by their ability to hydrolyze Asp-Leu. Although each of these activities hydrolyzes Asp-Leu at a measurable rate, the preferred substrates for both are N-terminal isoAsp peptides. One of the activities is a previously characterized isoAsp dipeptidase from E. coli, the product of the iadA gene. The other is the product of the serovar Typhimurium homolog of E. coli ybiK, a gene of previously unknown function. This gene product is a member of the N-terminal nucleophile structural family of amidohydrolases. Like most other members of this family, the mature enzyme is generated from a precursor protein by proteolytic cleavage and the active enzyme is a heterotetramer. Based on its ability to hydrolyze an N-terminal isoAsp tripeptide as well as isoAsp dipeptides, the enzyme appears to be an isoAsp aminopeptidase, and we propose that the gene encoding it be designated iaaA (isoAsp aminopeptidase). A strain lacking both IadA and IaaA in addition to peptidase B and peptidase E has been constructed. This strain utilizes Asp-Leu as a leucine source, and extracts of this strain contain at least one additional, as-yet-uncharacterized, peptidase able to cleave Asp dipeptides.

  17. Evaluation of Molecular Methods for Identification of Salmonella Serovars

    PubMed Central

    Gurnik, Simone; Ahmad, Aaminah; Blimkie, Travis; Murphy, Stephanie A.; Kropinski, Andrew M.; Nash, John H. E.

    2016-01-01

    Classification by serotyping is the essential first step in the characterization of Salmonella isolates and is important for surveillance, source tracking, and outbreak detection. To improve detection and reduce the burden of salmonellosis, several rapid and high-throughput molecular Salmonella serotyping methods have been developed. The aim of this study was to compare three commercial kits, Salm SeroGen (Salm Sero-Genotyping AS-1 kit), Check&Trace (Check-Points), and xMAP (xMAP Salmonella serotyping assay), to the Salmonella genoserotyping array (SGSA) developed by our laboratory. They were assessed using a panel of 321 isolates that represent commonly reported serovars from human and nonhuman sources globally. The four methods correctly identified 73.8% to 94.7% of the isolates tested. The methods correctly identified 85% and 98% of the clinically important Salmonella serovars Enteritidis and Typhimurium, respectively. The methods correctly identified 75% to 100% of the nontyphoidal, broad host range Salmonella serovars, including Heidelberg, Hadar, Infantis, Kentucky, Montevideo, Newport, and Virchow. The sensitivity and specificity of Salmonella serovars Typhimurium and Enteritidis ranged from 85% to 100% and 99% to 100%, respectively. It is anticipated that whole-genome sequencing will replace serotyping in public health laboratories in the future. However, at present, it is approximately three times more expensive than molecular methods. Until consistent standards and methodologies are deployed for whole-genome sequencing, data analysis and interlaboratory comparability remain a challenge. The use of molecular serotyping will provide a valuable high-throughput alternative to traditional serotyping. This comprehensive analysis provides a detailed comparison of commercial kits available for the molecular serotyping of Salmonella. PMID:27194688

  18. Occurrence of Salmonella enterica serovar Dublin in Austria.

    PubMed

    Allerberger, F; Liesegang, A; Grif, K; Prager, R; Danzl, J; Höck, F; Ottl, J; Dierich, M P; Berghold, C; Neckstaller, I; Tschäpe, H; Fisher, I

    2002-04-01

    In Austria, Salmonella enterica subsp. enterica serovar Dublin, a bovine-adapted serovar, rarely causes infections in humans. In 2000, Austria was within the European mean with an incidence of 0.1 per million inhabitants. Our data show that the vast majority of all serovar Dublin infections (human and non-human) can be traced epidemiologically to two districts in the Tyrol. This concentration of cases can be explained by a particularly traditional aspect of cattle farming in this area, the alpine pasture. There is an increased risk of cross infection due to the communal keeping of animals from various farms. Infected cattle are a source of infection for humans, and transmission usually occurs from eating beef and drinking cows milk. Using pulsed field gel electrophoresis and automated ribotyping, three out of five isolates from human infections could be traced to characteristic Tyrolean Dublin clones. Bacteriological screening for faecal carriage before the transfer of cattle from risk-herds to the alpine pastures and before the return from risk-pastures to the farms would be a possible starting point to prevent cross-contamination of large mixed herds and contamination of pasture through latently infected cattle. Appropriate research is necessary.

  19. Occurrence of Salmonella enterica serovar Dublin in Austria.

    PubMed

    Allerberger, Franz; Liesegang, Almut; Grif, Katharina; Khaschabi, Daryusch; Prager, Rita; Danzl, Johann; Höck, Franz; Ottl, Josef; Dierich, Manfred P; Berghold, Christian; Neckstaller, Ingeborg; Tschäpe, Helmut; Fisher, Ian

    2003-01-01

    In Austria, Salmonella enterica serovar Dublin, a bovine-adapted serovar, rarely causes human infections. In the year 2000, Austria was within the European mean with an incidence of 0.1 per million inhabitants. Our data show that the vast majority of all Austrian serovar Dublin infections can be traced to two Tyrolian districts. This concentration of cases can be explained by a particularly traditional aspect of cattle farming in Tyrol, the alpine pasture. There is increased risk of cross-infection due to the communal keeping of animals from various farms. Infected cattle are a source of infection for people, and contagion usually occurs from eating beef and drinking cow's milk. Using pulsed-field gel electrophoresis and automated ribotyping, 3 out of 5 available isolates from human infections could be traced to characteristic Tyrolian S. Dublin clones. Bacteriological screening of herds with a known history of S. Dublin infection would be a start to prevent future contamination of alpine pastures through latently infected cattle excreting potentially infectious feces. Bacteriological screening for fecal carriage before the return of cattle from pastures known to be connected with infections could prevent cross-contamination of large mixed herds.

  20. Generating pseudo large footprint waveforms from small footprint full-waveform airborne LiDAR data for the layered retrieval of LAI in orchards.

    PubMed

    Li, Wang; Niu, Zheng; Li, Jing; Chen, Hanyue; Gao, Shuai; Wu, Mingquan; Li, Dong

    2016-05-02

    Leaf area index (LAI) is a key parameter for the study of biogeochemical cycles in ecosystems. Remote sensing techniques have been widely used to estimate LAIs in a wide range of vegetation types. However, limited by the sensor detection capability, considerable fewer studies investigated the layered estimation of LAIs in the vertical direction, which can significantly affect the precision evaluation of vegetation biophysical and biochemical processes. This study tried to generate a kind of pseudo large footprint waveform from the small footprint full-waveform airborne LiDAR data by an aggregation approach. The layered distribution of canopy heights and LAIs were successfully retrieved based on the large footprint waveform data in an agricultural landscape of orchards with typical multi-layer vegetation covers. The Gaussian fitting was conducted on the normalized large footprint waveforms to identify the vertical positions for different vegetation layers. Then, the gap theory was applied to retrieve the layered LAIs. Statistically significant simple linear regression models were fitted between the LiDAR-retrieved and field-observed values for the canopy heights and LAIs in different layers. Satisfactory results were obtained with a root mean square error of 0.36 m for the overstorey canopy height (R2 = 0.82), 0.29 m for the understory canopy height (R2 = 0.76), 0.28 for overstorey LAI (R2 = 0.75), 0.40 for understory LAI (R2 = 0.64), and 0.38 for total LAI (R2 = 0.69), respectively. To conclude, estimating the layered LAIs in the multi-layer agriculture orchards from the pseudo large footprint waveforms is feasible and the estimation errors are acceptable, which will provide some new ideas and methods for the quantitative remote sensing with vegetation.

  1. A Unique Capsule Locus in the Newly Designated Actinobacillus pleuropneumoniae Serovar 16 and Development of a Diagnostic PCR Assay.

    PubMed

    Bossé, Janine T; Li, Yanwen; Sárközi, Rita; Gottschalk, Marcelo; Angen, Øystein; Nedbalcova, Katerina; Rycroft, Andrew N; Fodor, László; Langford, Paul R

    2017-03-01

    Actinobacillus pleuropneumoniae causes pleuropneumonia, an economically significant lung disease of pigs. Recently, isolates of A. pleuropneumoniae that were serologically distinct from the previously characterized 15 serovars were described, and a proposal was put forward that they comprised a new serovar, serovar 16. Here we used whole-genome sequencing of the proposed serovar 16 reference strain A-85/14 to confirm the presence of a unique capsular polysaccharide biosynthetic locus. For molecular diagnostics, primers were designed from the capsule locus of strain A-85/14, and a PCR was formulated that differentiated serovar 16 isolates from all 15 known serovars and other common respiratory pathogenic/commensal bacteria of pigs. Analysis of the capsule locus of strain A-85/14 combined with the previous serological data show the existence of a sixteenth serovar-designated serovar 16-of A. pleuropneumoniae.

  2. Draft Genome Sequence of Salmonella enterica subsp. enterica Serovar Give, Isolated from an Imported Chili Powder Product.

    PubMed

    Wang, Hua; Chen, Yi; Ayers, Sherry; Melka, David; Laasri, Anna; Payne, Justin S; Zheng, Jie; Son, Insook; Timme, Ruth; Kastanis, George; Hammack, Thomas S; Strain, Errol; Allard, Marc W; Evans, Peter S; Brown, Eric W

    2015-07-02

    We report the genome sequence of Salmonella enterica subsp. enterica serovar Give (CFSAN012622), isolated from imported chili powder in 2014. This genome contains genes previously reported to be specific only to S. enterica serovar Enteritidis. This strain shows a unique pulsed-field gel electrophoresis (PFGE) pattern clustering with serovar Enteritidis (JEG X01.0005).

  3. Draft Genome Sequences of 40 Salmonella enterica Serovar Typhimurium Strains Isolated from Humans and Food in Brazil

    PubMed Central

    Almeida, Fernanda; Medeiros, Marta Inês Cazentini; Rodrigues, Dália Prazeres; Payne, Justin; Timme, Ruth E.

    2016-01-01

    Salmonellosis is an important health problem worldwide and Salmonella enterica serovar Typhimurium is one of the most common isolated serovars. Here, we reported the draft genomes of 40 S. Typhimurium strains isolated from humans and food in Brazil. These draft genomes will improve phylogenetic analysis and will help enhance our understanding of strains of this serovar isolated in Brazil. PMID:27660768

  4. Draft Genome Sequences of 40 Salmonella enterica Serovar Typhimurium Strains Isolated from Humans and Food in Brazil.

    PubMed

    Almeida, Fernanda; Medeiros, Marta Inês Cazentini; Rodrigues, Dália Prazeres; Payne, Justin; Timme, Ruth E; Allard, Marc W; Falcão, Juliana Pfrimer

    2016-09-22

    Salmonellosis is an important health problem worldwide and Salmonella enterica serovar Typhimurium is one of the most common isolated serovars. Here, we reported the draft genomes of 40 S Typhimurium strains isolated from humans and food in Brazil. These draft genomes will improve phylogenetic analysis and will help enhance our understanding of strains of this serovar isolated in Brazil.

  5. Complete Genome Sequence of Leptospira alstonii Serovar Room22 Strain GWTS #1

    PubMed Central

    Bayles, Darrell O.; Hurley, Daniel; Fanning, Séamus; McMahon, Barry J.; Arent, Zbigniew

    2016-01-01

    We report here the complete genome sequence of Leptospira alstonii serovar Room22 strain GWTS #1. This is the first isolate of L. alstonii to be cultured from a mammal and in western Europe, and it represents a new serovar of pathogenic leptospires. PMID:27834698

  6. Genome-scale screening and validation of targets for identification of Salmonella enterica and serovar prediction

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica is the most common foodborne pathogen worldwide, with a great diversity of 2500 recognized serovars. Detection of S. enterica and its classification into serovars are essential for food safety surveillance and clinical diagnosis. Recently, the polymerase chain reaction (PCR) meth...

  7. Complete Genome Sequence of Salmonella enterica Serovar Enteritidis Bacteriophage f18SE, Isolated in Chile

    PubMed Central

    Segovia, Cristopher; Vasquez, Ignacio; Maracaja-Coutinho, Vinicius; Robeson, James

    2015-01-01

    Bacteriophage f18SE was isolated from poultry sewage in Olmue, Chile, and lytic activity was demonstrated against Salmonella enterica serovar Enteritidis and serovar Pullorum strains. This bacteriophage has a 41,868-bp double-stranded DNA (ds-DNA) genome encoding 53 coding sequences (CDSs) and belongs to the family Siphoviridae, subfamily Jerseyvirinae. PMID:26450716

  8. Differences in attachment of Salmonella enterica serovars to cabbage and lettuce leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigated the ability of five Salmonella enterica serovars to attach to and colonize intact and cut lettuce (Iceberg, Romaine) and cabbage surfaces. Biofilm assay and attachment of Salmonella serovars to intact and cut leaves were determined. Bacterial populations of loosely and strong...

  9. Development of Hamster Models for Acute and Chronic Infections with Leptospira borgpetersenii serovar Hardjo

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Golden Syrian hamster is frequently used as a small animal model to study acute leptospirosis. However, use of this small animal model to study Leptospira borgpetersenii serovar Hardjo infections has not been well documented. Cattle are the normal maintenance hosts of L. borgpetersenii serovar...

  10. Features of Two New Proteins with OmpA-Like Domains Identified in the Genome Sequences of Leptospira interrogans

    PubMed Central

    Teixeira, Aline F.; de Morais, Zenaide M.; Kirchgatter, Karin; Romero, Eliete C.; Vasconcellos, Silvio A.; Nascimento, Ana Lucia T. O.

    2015-01-01

    Leptospirosis is an acute febrile disease caused by pathogenic spirochetes of the genus Leptospira. It is considered an important re-emerging infectious disease that affects humans worldwide. The knowledge about the mechanisms by which pathogenic leptospires invade and colonize the host remains limited since very few virulence factors contributing to the pathogenesis of the disease have been identified. Here, we report the identification and characterization of two new leptospiral proteins with OmpA-like domains. The recombinant proteins, which exhibit extracellular matrix-binding properties, are called Lsa46 - LIC13479 and Lsa77 - LIC10050 (Leptospiral surface adhesins of 46 and 77 kDa, respectively). Attachment of Lsa46 and Lsa77 to laminin was specific, dose dependent and saturable, with KD values of 24.3 ± 17.0 and 53.0 ± 17.5 nM, respectively. Lsa46 and Lsa77 also bind plasma fibronectin, and both adhesins are plasminogen (PLG)-interacting proteins, capable of generating plasmin (PLA) and as such, increase the proteolytic ability of leptospires. The proteins corresponding to Lsa46 and Lsa77 are present in virulent L. interrogans L1-130 and in saprophyte L. biflexa Patoc 1 strains, as detected by immunofluorescence. The adhesins are recognized by human leptospirosis serum samples at the onset and convalescent phases of the disease, suggesting that they are expressed during infection. Taken together, our data could offer valuable information to the understanding of leptospiral pathogenesis. PMID:25849456

  11. Can key vegetation parameters be retrieved at the large-scale using LAI satellite products and a generic modelling approach ?

    NASA Astrophysics Data System (ADS)

    Dewaele, Helene; Calvet, Jean-Christophe; Carrer, Dominique; Laanaia, Nabil

    2016-04-01

    In the context of climate change, the need to assess and predict the impact of droughts on vegetation and water resources increases. The generic approaches permitting the modelling of continental surfaces at large-scale has progressed in recent decades towards land surface models able to couple cycles of water, energy and carbon. A major source of uncertainty in these generic models is the maximum available water content of the soil (MaxAWC) usable by plants which is constrained by the rooting depth parameter and unobservable at the large-scale. In this study, vegetation products derived from the SPOT/VEGETATION satellite data available since 1999 are used to optimize the model rooting depth over rainfed croplands and permanent grasslands at 1 km x 1 km resolution. The inter-annual variability of the Leaf Area Index (LAI) is simulated over France using the Interactions between Soil, Biosphere and Atmosphere, CO2-reactive (ISBA-A-gs) generic land surface model and a two-layer force-restore (FR-2L) soil profile scheme. The leaf nitrogen concentration directly impacts the modelled value of the maximum annual LAI. In a first step this parameter is estimated for the last 15 years by using an iterative procedure that matches the maximum values of LAI modelled by ISBA-A-gs to the highest satellite-derived LAI values. The Root Mean Square Error (RMSE) is used as a cost function to be minimized. In a second step, the model rooting depth is optimized in order to reproduce the inter-annual variability resulting from the drought impact on the vegetation. The evaluation of the retrieved soil rooting depth is achieved using the French agricultural statistics of Agreste. Retrieved leaf nitrogen concentrations are compared with values from previous studies. The preliminary results show a good potential of this approach to estimate these two vegetation parameters (leaf nitrogen concentration, MaxAWC) at the large-scale over grassland areas. Besides, a marked impact of the

  12. Modelling LAI, surface water and carbon fluxes at high-resolution over France: comparison of ISBA-A-gs and ORCHIDEE

    NASA Astrophysics Data System (ADS)

    Lafont, S.; Zhao, Y.; Calvet, J.-C.; Peylin, P.; Ciais, P.; Maignan, F.; Weiss, M.

    2011-07-01

    The Leaf Area Index (LAI) is a measure of the amount of photosynthetic leaves and governs the canopy conductance to water vapor and carbon dioxide. Four different estimates of LAI were compared over France: two LAI products derived from satellite remote sensing, and two LAI simulations derived from land surface modelling. The simulated LAI was produced by the ISBA-A-gs model and by the ORCHIDEE model (developed by CNRM-GAME and by IPSL, respectively), for the 1994-2007 period. The two models were driven by the same atmospheric variables and used the same land cover map (SAFRAN and ECOCLIMAP-II, respectively). The MODIS and CYCLOPES satellite LAI products were used. Both products were available from 2000 to 2007 and this relatively long period allowed to investigate the interannual and the seasonal variability of monthly LAI values. In particular the impact of the 2003 and 2005 droughts were analyzed. The two models presented contrasting results, with a difference of one month between the average leaf onset dates simulated by the two models, and a maximum interannual variability of LAI simulated at springtime by ORCHIDEE and at summertime by ISBA-A-gs. The comparison with the satellite LAI products showed that, in general, the seasonality was better represented by ORCHIDEE, while ISBA-A-gs tended to better represent the interannual variability, especially for grasslands. While the two models presented comparable values of net carbon fluxes, ORCHIDEE simulated much higher photosynthesis rates than ISBA-A-gs (+70 %), while providing lower transpiration estimates (-8 %).

  13. Modelling LAI, surface water and carbon fluxes at high-resolution over France: comparison of ISBA-A-gs and ORCHIDEE

    NASA Astrophysics Data System (ADS)

    Lafont, S.; Zhao, Y.; Calvet, J.-C.; Peylin, P.; Ciais, P.; Maignan, F.; Weiss, M.

    2012-01-01

    The Leaf Area Index (LAI) is a measure of the amount of photosynthetic leaves and governs the canopy conductance to water vapor and carbon dioxide. Four different estimates of LAI were compared over France: two LAI products derived from satellite remote sensing, and two LAI simulations derived from land surface modelling. The simulated LAI was produced by the ISBA-A-gs model and by the ORCHIDEE model (developed by CNRM-GAME and by IPSL, respectively), for the 1994-2007 period. The two models were driven by the same atmospheric variables and used the same land cover map (SAFRAN and ECOCLIMAP-II, respectively). The MODIS and CYCLOPES satellite LAI products were used. Both products were available from 2000 to 2007 and this relatively long period allowed to investigate the interannual and the seasonal variability of monthly LAI values. In particular the impact of the 2003 and 2005 droughts were analyzed. The two models presented contrasting results, with a difference of one month between the average leaf onset dates simulated by the two models, and a maximum interannual variability of LAI simulated at springtime by ORCHIDEE and at summertime by ISBA-A-gs. The comparison with the satellite LAI products showed that, in general, the seasonality was better represented by ORCHIDEE, while ISBA-A-gs tended to better represent the interannual variability, especially for grasslands. While the two models presented comparable values of net carbon fluxes, ORCHIDEE simulated much higher photosynthesis rates than ISBA-A-gs (+70%), while providing lower transpiration estimates (-8%).

  14. Inter-kingdom Signaling by the Legionella Quorum Sensing Molecule LAI-1 Modulates Cell Migration through an IQGAP1-Cdc42-ARHGEF9-Dependent Pathway.

    PubMed

    Simon, Sylvia; Schell, Ursula; Heuer, Natalie; Hager, Dominik; Albers, Michael F; Matthias, Jan; Fahrnbauer, Felix; Trauner, Dirk; Eichinger, Ludwig; Hedberg, Christian; Hilbi, Hubert

    2015-12-01

    Small molecule signaling promotes the communication between bacteria as well as between bacteria and eukaryotes. The opportunistic pathogenic bacterium Legionella pneumophila employs LAI-1 (3-hydroxypentadecane-4-one) for bacterial cell-cell communication. LAI-1 is produced and detected by the Lqs (Legionella quorum sensing) system, which regulates a variety of processes including natural competence for DNA uptake and pathogen-host cell interactions. In this study, we analyze the role of LAI-1 in inter-kingdom signaling. L. pneumophila lacking the autoinducer synthase LqsA no longer impeded the migration of infected cells, and the defect was complemented by plasmid-borne lqsA. Synthetic LAI-1 dose-dependently inhibited cell migration, without affecting bacterial uptake or cytotoxicity. The forward migration index but not the velocity of LAI-1-treated cells was reduced, and the cell cytoskeleton appeared destabilized. LAI-1-dependent inhibition of cell migration involved the scaffold protein IQGAP1, the small GTPase Cdc42 as well as the Cdc42-specific guanine nucleotide exchange factor ARHGEF9, but not other modulators of Cdc42, or RhoA, Rac1 or Ran GTPase. Upon treatment with LAI-1, Cdc42 was inactivated and IQGAP1 redistributed to the cell cortex regardless of whether Cdc42 was present or not. Furthermore, LAI-1 reversed the inhibition of cell migration by L. pneumophila, suggesting that the compound and the bacteria antagonistically target host signaling pathway(s). Collectively, the results indicate that the L. pneumophila quorum sensing compound LAI-1 modulates migration of eukaryotic cells through a signaling pathway involving IQGAP1, Cdc42 and ARHGEF9.

  15. Inter-kingdom Signaling by the Legionella Quorum Sensing Molecule LAI-1 Modulates Cell Migration through an IQGAP1-Cdc42-ARHGEF9-Dependent Pathway

    PubMed Central

    Simon, Sylvia; Schell, Ursula; Heuer, Natalie; Hager, Dominik; Albers, Michael F.; Matthias, Jan; Fahrnbauer, Felix; Trauner, Dirk; Eichinger, Ludwig; Hedberg, Christian; Hilbi, Hubert

    2015-01-01

    Small molecule signaling promotes the communication between bacteria as well as between bacteria and eukaryotes. The opportunistic pathogenic bacterium Legionella pneumophila employs LAI-1 (3-hydroxypentadecane-4-one) for bacterial cell-cell communication. LAI-1 is produced and detected by the Lqs (Legionella quorum sensing) system, which regulates a variety of processes including natural competence for DNA uptake and pathogen-host cell interactions. In this study, we analyze the role of LAI-1 in inter-kingdom signaling. L. pneumophila lacking the autoinducer synthase LqsA no longer impeded the migration of infected cells, and the defect was complemented by plasmid-borne lqsA. Synthetic LAI-1 dose-dependently inhibited cell migration, without affecting bacterial uptake or cytotoxicity. The forward migration index but not the velocity of LAI-1-treated cells was reduced, and the cell cytoskeleton appeared destabilized. LAI-1-dependent inhibition of cell migration involved the scaffold protein IQGAP1, the small GTPase Cdc42 as well as the Cdc42-specific guanine nucleotide exchange factor ARHGEF9, but not other modulators of Cdc42, or RhoA, Rac1 or Ran GTPase. Upon treatment with LAI-1, Cdc42 was inactivated and IQGAP1 redistributed to the cell cortex regardless of whether Cdc42 was present or not. Furthermore, LAI-1 reversed the inhibition of cell migration by L. pneumophila, suggesting that the compound and the bacteria antagonistically target host signaling pathway(s). Collectively, the results indicate that the L. pneumophila quorum sensing compound LAI-1 modulates migration of eukaryotic cells through a signaling pathway involving IQGAP1, Cdc42 and ARHGEF9. PMID:26633832

  16. [Salmonella serovars isolated in Turkey up to the end of year 2011].

    PubMed

    Töreci, Kurtuluş; Erdem, Birsel; Ongen, Betigül

    2013-07-01

    Bacteria in Salmonella genus are separated into more than 2600 serovars. It is important that the isolated serovars and their sources are known in a certain country. This will help the identification of new Salmonella serovars that will be isolated later on. Since there is no Salmonella reference center in Turkey, Salmonella serovars isolated in Turkey were mainly reported by the articles of Aksoycan's manuscripts in various years, and in the list of Töreci and Anğ in 1991. The aim of this meta-analysis was to detect and prepare a list for all the Salmonella serovars isolated from human and non-human samples in Turkey up to the end of 2011. In creating this serovar list, libraries, personal and institutional archives, theses, publication lists, books published after scientific meetings and congresses, and international and local periodicals have been explored, and members of Turkish Microbiology Society are communicated via the web site of the society and personal e-mail addresses, and their publications regarding Salmonella serovars were requested. The list also includes the modifications on the names and antigenic formulae of the serovars that were carried out in recent years. The number of serovars isolated in Turkey up to the end of 2011 is 129. Fifty three of them were isolated from humans, 38 from humans and non-human samples, and 38 from non-human samples. The total number of serovars isolated from humans is 91. Twenty seven serovars from serogrup 0:4 (B); 23 serovars from serogrup 0:7 (C1); 25 serovars from serogrup 0:8 (C2-C3); 16 serovars from serogrup 0:9 (D1); 8 serovars from serogrup 0:3,10 (E1) and 5 serovars from serogrup 0:28 (M) have been reported. Only two of the more than 2600 serovars known were isolated firstly in Turkey: S. Istanbul (8:z10: e,n,x) in 1969 and S. Adana (43:z10:1,5) in 1977. Previously, serovars containing 1 and 25 O antigen of S. Boecker ([1],6,14,[25]) were isolated in 1967 and 1971 for the first time in Turkey. In 1967, a

  17. Characterization of a Monoclonal Antibody Directed against Salmonella enterica Serovar Typhimurium and Serovar [4,5,12:i:−] ▿

    PubMed Central

    Rementeria, A.; Vivanco, A. B.; Ramirez, A.; Hernando, F. L.; Bikandi, J.; Herrera-León, S.; Echeita, A.; Garaizar, J.

    2009-01-01

    Flagellar extracts of Salmonella enterica serovars expressing phase 2 H1 antigenic complex (H:1,2, H:1,5, H:1,6, and H:1,7) and a mutant flagellin obtained by site-directed mutagenesis of the fljB gene from serovar Typhimurium at codon 218, transforming threonine to alanine, expressed in Escherichia coli (fljB218A) were used to analyze the H1 antigenic complex. Cross-reactions were detected by Western blotting and dot blotting using commercial polyclonal antibodies against the different wild-type extracts and mutant FljB218A. Therefore, we produced a monoclonal antibody (MAb), 23D4, isotyped as immunoglobulin M, against H:1,2 S. enterica serovar Typhimurium flagellin. The mutant flagellin was not recognized by this MAb. When a large number of phase 1 and phase 2 flagellin antigens of different serovars were used to characterize the 23D4 MAb, only extracts of serovars Typhimurium and [4,5,12:i:−] reacted. The protein composition of phase 1 and phase 2 extracts and highly purified H:1,2 flagellin from serovar Typhimurium strain LT2 and extract of strain 286 (serovar [4,5,12:i:−]), which reacted with the MAb, was studied. Phase 2 flagellin (FljBH:1,2) was detected in phase 1 and phase 2 flagellar heat extracts of serovar Typhimurium and was the single protein identified in all spots of purified H:1,2 flagellin. FliC, FlgK, and other proteins were detected in some immunoreactive spots and in the flagellar extract of serovar [4,5,12:i:−]. Immunoelectron microscopy of complete bacteria with 23D4 showed MAb attachment at the base of flagella, although the MAb failed to recognize the filament of flagella. Nevertheless, the results obtained by the other immunological tests (enzyme-linked immunosorbent assay, Western blotting, and dot blotting) indicate a reaction against flagellins. The epitopes could also be shared by other proteins on spots where FljB is not present, such as aminopeptidase B, isocitrate lyase, InvE, EF-TuA, enolase, DnaK, and others. In conclusion

  18. Spatial Heterogeneity of Leaf Area Index (LAI) and Its Temporal Course on Arable Land: Combining Field Measurements, Remote Sensing and Simulation in a Comprehensive Data Analysis Approach (CDAA)

    PubMed Central

    Korres, Wolfgang; Montzka, Carsten; Fiener, Peter; Wilken, Florian; Stadler, Anja; Waldhoff, Guido; Schneider, Karl

    2016-01-01

    The ratio of leaf area to ground area (leaf area index, LAI) is an important state variable in ecosystem studies since it influences fluxes of matter and energy between the land surface and the atmosphere. As a basis for generating temporally continuous and spatially distributed datasets of LAI, the current study contributes an analysis of its spatial variability and spatial structure. Soil-vegetation-atmosphere fluxes of water, carbon and energy are nonlinearly related to LAI. Therefore, its spatial heterogeneity, i.e., the combination of spatial variability and structure, has an effect on simulations of these fluxes. To assess LAI spatial heterogeneity, we apply a Comprehensive Data Analysis Approach that combines data from remote sensing (5 m resolution) and simulation (150 m resolution) with field measurements and a detailed land use map. Test area is the arable land in the fertile loess plain of the Rur catchment on the Germany-Belgium-Netherlands border. LAI from remote sensing and simulation compares well with field measurements. Based on the simulation results, we describe characteristic crop-specific temporal patterns of LAI spatial variability. By means of these patterns, we explain the complex multimodal frequency distributions of LAI in the remote sensing data. In the test area, variability between agricultural fields is higher than within fields. Therefore, spatial resolutions less than the 5 m of the remote sensing scenes are sufficient to infer LAI spatial variability. Frequency distributions from the simulation agree better with the multimodal distributions from remote sensing than normal distributions do. The spatial structure of LAI in the test area is dominated by a short distance referring to field sizes. Longer distances that refer to soil and weather can only be derived from remote sensing data. Therefore, simulations alone are not sufficient to characterize LAI spatial structure. It can be concluded that a comprehensive picture of LAI spatial

  19. Complete Genome and Methylome Sequences of Salmonella enterica subsp. enterica Serovar Panama (ATCC 7378) and Salmonella enterica subsp. enterica Serovar Sloterdijk (ATCC 15791)

    PubMed Central

    Yao, Kuan; Muruvanda, Tim; Roberts, Richard J.; Payne, Justin; Allard, Marc W.

    2016-01-01

    Salmonella enterica spp. are pathogenic bacteria commonly associated with food-borne outbreaks in human and animals. Salmonella enterica spp. are characterized into more than 2,500 different serotypes, which makes epidemiological surveillance and outbreak control more difficult. In this report, we announce the first complete genome and methylome sequences from two Salmonella type strains associated with food-borne outbreaks, Salmonella enterica subsp. enterica serovar Panama (ATCC 7378) and Salmonella enterica subsp. enterica serovar Sloterdijk (ATCC 15791). PMID:26988049

  20. Complete Genome and Methylome Sequences of Salmonella enterica subsp. enterica Serovar Panama (ATCC 7378) and Salmonella enterica subsp. enterica Serovar Sloterdijk (ATCC 15791).

    PubMed

    Yao, Kuan; Muruvanda, Tim; Roberts, Richard J; Payne, Justin; Allard, Marc W; Hoffmann, Maria

    2016-03-17

    Salmonella enterica spp. are pathogenic bacteria commonly associated with food-borne outbreaks in human and animals. Salmonella enterica spp. are characterized into more than 2,500 different serotypes, which makes epidemiological surveillance and outbreak control more difficult. In this report, we announce the first complete genome and methylome sequences from two Salmonella type strains associated with food-borne outbreaks, Salmonella enterica subsp. enterica serovar Panama (ATCC 7378) and Salmonella enterica subsp. enterica serovar Sloterdijk (ATCC 15791).

  1. Evaluation of Sentinel-2 red-edge bands for empirical estimation of green LAI and chlorophyll content.

    PubMed

    Delegido, Jesús; Verrelst, Jochem; Alonso, Luis; Moreno, José

    2011-01-01

    ESA's upcoming satellite Sentinel-2 will provide Earth images of high spatial, spectral and temporal resolution and aims to ensure continuity for Landsat and SPOT observations. In comparison to the latter sensors, Sentinel-2 incorporates three new spectral bands in the red-edge region, which are centered at 705, 740 and 783 nm. This study addresses the importance of these new bands for the retrieval and monitoring of two important biophysical parameters: green leaf area index (LAI) and chlorophyll content (Ch). With data from several ESA field campaigns over agricultural sites (SPARC, AgriSAR, CEFLES2) we have evaluated the efficacy of two empirical methods that specifically make use of the new Sentinel-2 bands. First, it was shown that LAI can be derived from a generic normalized difference index (NDI) using hyperspectral data, with 674 nm with 712 nm as best performing bands. These bands are positioned closely to the Sentinel-2 B4 (665 nm) and the new red-edge B5 (705 nm) band. The method has been applied to simulated Sentinel-2 data. The resulting green LAI map was validated against field data of various crop types, thereby spanning a LAI between 0 and 6, and yielded a RMSE of 0.6. Second, the recently developed "Normalized Area Over reflectance Curve" (NAOC), an index that derives Ch from hyperspectral data, was studied on its compatibility with simulated Sentinel-2 data. This index integrates the reflectance curve between 643 and 795 nm, thereby including the new Sentinel-2 bands in the red-edge region. We found that these new bands significantly improve the accuracy of Ch estimation. Both methods emphasize the importance of red-edge bands for operational estimation of biophysical parameters from Sentinel-2.

  2. Hemagglutinating activity of serovar reference strains of Ornithobacterium rhinotracheale.

    PubMed

    Vega, Vicente; Zepeda, Andrea; Ramírez, Saúl; Morales, Vladimir; Fernández, Pomposo; de Oca, Roberto Montes; Guerra-Infante, Fernando M; de Jesús de Haro-Cruz, María; Blackall, Patrick J; Soriano, Edgardo V

    2008-05-01

    In the present study, the hemagglutinating activity of 9 reference strains (serovars A-I) of Ornithobacterium rhinotracheale was investigated by using fresh erythrocytes from 15 different species: chicken (broiler, rooster, hen), turkey, pigeon, quail, duck, Harris hawk (Parabuteo unicinctus), house finch (Carpodacus mexicanus), cow, sheep, horse, dog, rabbit, pig, human (groups A, B, AB, and O), and rainbow trout (Oncorhynchus mykiss). All 9 strains agglutinated rabbit erythrocytes. None of the strains was able to agglutinate hen, cow, horse, or rainbow trout erythrocytes. The number of positive reactions among the remaining species varied. Results indicate that the use of rabbit erythrocytes is better suited for testing the hemagglutinating activity of O. rhinotracheale.

  3. Sensitivity of the Weather Research and Forecast/Community Multiscale Air Quality modeling system to MODIS LAI, FPAR, and albedo

    NASA Astrophysics Data System (ADS)

    Ran, Limei; Gilliam, Robert; Binkowski, Francis S.; Xiu, Aijun; Pleim, Jonathan; Band, Larry

    2015-08-01

    This study aims to improve land surface processes in a retrospective meteorology and air quality modeling system through the use of Moderate Resolution Imaging Spectroradiometer (MODIS) vegetation and albedo products for more realistic vegetation and surface representation. MODIS leaf area index (LAI), fraction of absorbed photosynthetically active radiation (FPAR), and albedo are incorporated into the Pleim-Xiu land surface model (PX LSM) used in a combined meteorology and air quality modeling system. The current PX LSM intentionally exaggerates vegetation coverage and LAI in western dry lands so that its soil moisture nudging scheme is more effective in simulating surface temperature and mixing ratio. Reduced vegetation coverage from the PX LSM with MODIS input results in hotter and dryer daytime conditions with reduced ozone dry deposition velocities in much of western North America. Evaluations of the new system indicate greater error and bias in temperature, but reduced error and bias in moisture with the MODIS vegetation input. Hotter daytime temperatures and reduced dry deposition result in greater ozone concentrations in the western arid regions even with deeper boundary layer depths. MODIS albedo has much less impact on the meteorology simulations than MODIS LAI and FPAR. The MODIS vegetation and albedo input does not have much influence in the east where differences in vegetation and albedo parameters are less extreme. Evaluation results showing increased temperature errors with more accurate representation of vegetation suggests that improvements are needed in the model surface physics, particularly the soil processes in the PX LSM.

  4. Gonococcal infection in Edinburgh and Newcastle: serovar prevalence in relation to clinical features and sexual orientation.

    PubMed Central

    Ross, J D; Wardropper, A; Sprott, M; Moyes, A; Young, H

    1994-01-01

    AIMS--The variable distribution of gonococcal serovars in different areas is well recognised but the factors that are important determinants of serovar prevalence are less clear. The aim of this study was to identify relevant clinical variables by comparing serovar prevalence in two cities over the same time period. METHODS--A prospective analysis of serovar prevalence was made between January and December 1992 in Edinburgh and Newcastle with respect to age, sex, sexual orientation, antibiotic sensitivity and presence of symptoms. RESULTS--224 infective episodes of gonorrhoea were studied. The serovar distribution varied between the two cities with serovar 1B-1 being more common in Edinburgh (20/91 cf. 4/133, p < 0.01) and serovar 1B-6 more common in Newcastle (26/133 cf. 2/91, p < 0.01). Serovar 1A-2 was associated with heterosexual infection (35/114 in heterosexuals cf. 0/85 in homosexuals, p < 0.01) and was more sensitive to penicillin than average (39/39 1A-2 strains highly penicillin sensitive cf. 98/184 for all other strains, p < 0.01) whilst 1B-6 was mostly acquired through homosexual contact (22/26 cf. 63/142 for all other strains, p < 0.01) and tended to show reduced penicillin susceptibility (13/28 1B-6 strains less penicillin sensitive cf. 45/195 for all other strains, p < 0.01). Infection with serovar 1A-2 was significantly less often symptomatic in heterosexuals than average (15/33 asymptomatic 1A-2 infections cf. 17/59 for all other serovars, p = 0.015). Subgroup analysis of male heterosexual infections confirms an association between asymptomatic infection and serovar 1A-2 (2/14 asymptomatic 1A-2 infections cf. 1/72 for all other serovars, p = 0.02). The distribution of infections over the year differed between the cities. CONCLUSIONS--A variety of factors including penicillin sensitivity and virulence may be important in determining the prevalence of gonococcal serovars within a given area. PMID:8300098

  5. A Unique Capsule Locus in the Newly Designated Actinobacillus pleuropneumoniae Serovar 16 and Development of a Diagnostic PCR Assay

    PubMed Central

    Li, Yanwen; Sárközi, Rita; Gottschalk, Marcelo; Angen, Øystein; Nedbalcova, Katerina; Rycroft, Andrew N.; Fodor, László

    2017-01-01

    ABSTRACT Actinobacillus pleuropneumoniae causes pleuropneumonia, an economically significant lung disease of pigs. Recently, isolates of A. pleuropneumoniae that were serologically distinct from the previously characterized 15 serovars were described, and a proposal was put forward that they comprised a new serovar, serovar 16. Here we used whole-genome sequencing of the proposed serovar 16 reference strain A-85/14 to confirm the presence of a unique capsular polysaccharide biosynthetic locus. For molecular diagnostics, primers were designed from the capsule locus of strain A-85/14, and a PCR was formulated that differentiated serovar 16 isolates from all 15 known serovars and other common respiratory pathogenic/commensal bacteria of pigs. Analysis of the capsule locus of strain A-85/14 combined with the previous serological data show the existence of a sixteenth serovar—designated serovar 16—of A. pleuropneumoniae. PMID:28053219

  6. Infection of Mice by Salmonella enterica Serovar Enteritidis Involves Additional Genes That Are Absent in the Genome of Serovar Typhimurium

    PubMed Central

    Silva, Cecilia A.; Blondel, Carlos J.; Quezada, Carolina P.; Porwollik, Steffen; Andrews-Polymenis, Helene L.; Toro, Cecilia S.; Zaldívar, Mercedes; Contreras, Inés

    2012-01-01

    Salmonella enterica serovar Enteritidis causes a systemic, typhoid-like infection in newly hatched poultry and mice. In the present study, a library of 54,000 transposon mutants of S. Enteritidis phage type 4 (PT4) strain P125109 was screened for mutants deficient in the in vivo colonization of the BALB/c mouse model using a microarray-based negative-selection screening. Mutants in genes known to contribute to systemic infection (e.g., Salmonella pathogenicity island 2 [SPI-2], aro, rfa, rfb, phoP, and phoQ) and enteric infection (e.g., SPI-1 and SPI-5) in this and other Salmonella serovars displayed colonization defects in our assay. In addition, a strong attenuation was observed for mutants in genes and genomic islands that are not present in S. Typhimurium or in most other Salmonella serovars. These genes include a type I restriction/modification system (SEN4290 to SEN4292), the peg fimbrial operon (SEN2144A to SEN2145B), a putative pathogenicity island (SEN1970 to SEN1999), and a type VI secretion system remnant SEN1001, encoding a hypothetical protein containing a lysin motif (LysM) domain associated with peptidoglycan binding. Proliferation defects for mutants in these individual genes and in exemplar genes for each of these clusters were confirmed in competitive infections with wild-type S. Enteritidis. A ΔSEN1001 mutant was defective for survival within RAW264.7 murine macrophages in vitro. Complementation assays directly linked the SEN1001 gene to phenotypes observed in vivo and in vitro. The genes identified here may perform novel virulence functions not characterized in previous Salmonella models. PMID:22083712

  7. Empirical and Statistical Approaches for the Improved Retrieval of Chlorohyll and LAI from Sentinel-2 Data

    NASA Astrophysics Data System (ADS)

    Verrelst, J.; Alonso, L.; Camps-Valls, G.; Delegido, J.; Guanter, L.; Contreras Marin, C. J.; Acosta Rubiano, J.; Meza Naranjo, C. M.; Moreno, J.

    2010-12-01

    This work evaluates two novel approaches, empirical and statistical, for the estimation of leaf chlorophyll (Chlab), leaf area index (LAI) and fractional vegetation cover (fCOVER). The empirical approach calculates the continuum spectral region sensitive to Chlab with the so-called Normalized Area Over reflectance curve (NAOC). The performance of NAOC was compared against the performance of established and generic narrowband vegetation indices. However, as not all available bands take part in these methods it remains ambiguous whether best fittings were achieved. Alternatively, the statistical approach is based on Gaussian processes (GP) and allows inclusion of all bands. GP builds a nonlinear regression as a linear combination of spectra mapped to a high dimensional space. Besides, GP provides an indication of the most contributing bands for each parameter, a weight for the most relevant spectra, and a confidence estimate of the retrieval. Hyperspectral CHRIS data and resampling to Sentinel-2 configuration was conducted in the experiments. Results from the Spanish Barrax test site shows that GP outperforms the empirical approaches in assess- ing the vegetation properties when using at least four out of 62 CHRIS bands. It was found that the most contributing bands were situated in the red and red edge spectra regions, and to a lower extent in the blue and NIR parts of the spectrum. Since the proposed empirical and statistical methods consist of simple relationships between the parameter and a few bands they can be easily applied to multispectral data, as long as the relevant bands are available, as it is the case with Sentinel-2.

  8. Kidney allograft pyelonephritis caused by Salmonella enterica serovar Schwarzengrund.

    PubMed

    Ito, Kenta; Nishio, Haruomi; Iwatani, Yuji; Yamada, Ryo; Okawa, Takao; Yamamoto, Takumi; Murakami, Masaaki; Matsuo, Yoko; Matsuo, Ken; Tanaka, Satoshi; Mori, Kiyoshi; Mori, Noriko

    2017-03-13

    Kidney transplant recipients (KTRs) taking immunosuppressive drugs have a 20-fold greater risk of nontyphoidal Salmonella (NTS) infection than the healthy adult population. Among KTRs, the urinary tract is the most common site of infection. However, few cases of urinary tract infection caused by NTS have been documented in KTRs, and only one in Japan. Furthermore, it frequently induces acute allograft rejection with high mortality. Salmonella enterica subsp. enterica serovar Schwarzengrund (S. Schwarzengrund) is now among the more common Salmonella serovars isolated in Japan and is likely to be invasive. We present a case of a 45-year old female with vesicoureteral reflux to her transplanted kidney who developed kidney allograft pyelonephritis caused by S. Schwarzengrund. She was admitted to our hospital with fever, urodynia, lower abdominal pain, gross hematuria, and cloudy urine. Urine cultures were positive for S. Schwarzengrund. Exposure to cats, especially stray cats, were identified as the most likely source. We administered antibiotics for 4 weeks (ceftriaxone then amoxicillin, each for 2 weeks) and educated her about pet safety. She experienced no recurrence of infection or clinical kidney allograft rejection for 3 months post-treatment. NTS should be considered as a possible pathogen of urinary tract infection among KTRs, especially in cases with animal exposure or structural urologic abnormalities. When the pathogen is NTS, appropriate antibiotics and treatment periods are essential for preventing recurrence and allograft rejection after the completion of treatment.

  9. Epidemiology of Leptospira weilii serovar Topaz infections in Australia.

    PubMed

    Slack, Andrew T; Symonds, Meegan L; Dohnt, Michael F; Corney, Bruce G; Smythe, Lee D

    2007-06-01

    Leptospirosis is a zoonotic disease with a worldwide distribution. Leptospira weilii serovar (sv.) Topaz is a newly described serovar first isolated in the far north of Queensland, Australia. The epidemiology of L. weilii sv. Topaz infections in Australia was characterised through the use of surveillance questionnaires and molecular studies. There have been 24 human and 2 animal (bovine and bandicoot) L. weilii sv. Topaz infections diagnosed since 1991. The majority of these infections have occurred in Far North Queensland, with the remaining infections occurring in South East Queensland and in Western Australia. The majority of patients with L. weilii sv. Topaz infections presented with classical leptospirosis symptoms including; fever, headaches, sweats, chills and myalgia. The occupations of human cases of L. weilii sv. Topaz infection included banana farming, dairy and beef cattle production and tourist related activities. Fluorescent amplified fragment length polymorphism (FAFLP) was performed on 15 L. weilii sv. Topaz isolates including 2 animal isolates. Clustering analysis grouped the 15 isolates into 5 main clades with 13 unique FAFLP profiles. A high level of relatedness was demonstrated between 2 animal and 2 human isolates.

  10. The distribution of Salmonella enterica serovars and subtypes in surface water from five agricultural regions across Canada.

    PubMed

    Jokinen, C C; Koot, J; Cole, L; Desruisseau, A; Edge, T A; Khan, I U H; Koning, W; Lapen, D R; Pintar, K D M; Reid-Smith, R; Thomas, J L; Topp, E; Wang, L Y; Wilkes, G; Ziebell, K; van Bochove, E; Gannon, V P J

    2015-06-01

    Serovar prevalence of the zoonotic pathogen, Salmonella enterica, was compared among 1624 surface water samples collected previously from five different Canadian agricultural watersheds over multiple years. Phagetyping, pulsed field gel electrophoresis (PFGE), and antimicrobial resistance subtyping assays were performed on serovars Enteritidis, Typhimurium, and Heidelberg. Serovars and subtypes from surface water were compared with those from animal feces, human sewage, and serovars reported to cause salmonellosis in Canadians. Sixty-five different serovars were identified in surface water; only 32% of these were isolated from multiple watersheds. Eleven of the 13 serovars most commonly reported to cause salmonellosis in Canadians were identified in surface water; isolates of these serovars constituted >40% of the total isolates. Common phagetypes and PFGE subtypes of serovars associated with illness in humans such as S. Enteritidis and S. Typhimurium were also isolated from surface water and animal feces. Antimicrobial resistance was generally low, but was highest among S. Typhimurium. Monitoring of these rivers helps to identify vulnerable areas of a watershed and, despite a relatively low prevalence of S. enterica overall, serovars observed in surface water are an indication of the levels of specific S. enterica serovars present in humans and animals.

  11. Development of two real-time polymerase chain reaction assays to detect Actinobacillus pleuropneumoniae serovars 1-9-11 and serovar 2.

    PubMed

    Marois-Créhan, Corinne; Lacouture, Sonia; Jacques, Mario; Fittipaldi, Nahuel; Kobisch, Marylène; Gottschalk, Marcelo

    2014-01-01

    Two real-time, or quantitative, polymerase chain reaction (qPCR) assays were developed to detect Actinobacillus pleuropneumoniae serovars 1-9-11 (highly related serovars with similar virulence potential) and serovar 2, respectively. The specificity of these assays was verified on a collection of 294 strains, which included all 16 reference A. pleuropneumoniae strains (including serovars 5a and 5b), 263 A. pleuropneumoniae field strains isolated between 1992 and 2009 in different countries, and 15 bacterial strains other than A. pleuropneumoniae. The detection levels of both qPCR tests were evaluated using 10-fold dilutions of chromosomal DNA from reference strains of A. pleuropneumoniae serovars 1 and 2, and the detection limit for both assays was 50 fg per assay. The analytical sensitivities of the qPCR tests were also estimated by using pure cultures and tonsils experimentally spiked with A. pleuropneumoniae. The detection threshold was 2.5 × 10(4) colony forming units (CFU)/ml and 2.9 × 10(5) CFU/0.1 g of tonsil, respectively, for both assays. These specific and sensitive tests can be used for the serotyping of A. pleuropneumoniae in diagnostic laboratories to control porcine pleuropneumonia.

  12. Experimental Sentinel-2 LAI estimation using parametric, non-parametric and physical retrieval methods - A comparison

    NASA Astrophysics Data System (ADS)

    Verrelst, Jochem; Rivera, Juan Pablo; Veroustraete, Frank; Muñoz-Marí, Jordi; Clevers, Jan G. P. W.; Camps-Valls, Gustau; Moreno, José

    2015-10-01

    Given the forthcoming availability of Sentinel-2 (S2) images, this paper provides a systematic comparison of retrieval accuracy and processing speed of a multitude of parametric, non-parametric and physically-based retrieval methods using simulated S2 data. An experimental field dataset (SPARC), collected at the agricultural site of Barrax (Spain), was used to evaluate different retrieval methods on their ability to estimate leaf area index (LAI). With regard to parametric methods, all possible band combinations for several two-band and three-band index formulations and a linear regression fitting function have been evaluated. From a set of over ten thousand indices evaluated, the best performing one was an optimized three-band combination according to (ρ560 -ρ1610 -ρ2190) / (ρ560 +ρ1610 +ρ2190) with a 10-fold cross-validation RCV2 of 0.82 (RMSECV : 0.62). This family of methods excel for their fast processing speed, e.g., 0.05 s to calibrate and validate the regression function, and 3.8 s to map a simulated S2 image. With regard to non-parametric methods, 11 machine learning regression algorithms (MLRAs) have been evaluated. This methodological family has the advantage of making use of the full optical spectrum as well as flexible, nonlinear fitting. Particularly kernel-based MLRAs lead to excellent results, with variational heteroscedastic (VH) Gaussian Processes regression (GPR) as the best performing method, with a RCV2 of 0.90 (RMSECV : 0.44). Additionally, the model is trained and validated relatively fast (1.70 s) and the processed image (taking 73.88 s) includes associated uncertainty estimates. More challenging is the inversion of a PROSAIL based radiative transfer model (RTM). After the generation of a look-up table (LUT), a multitude of cost functions and regularization options were evaluated. The best performing cost function is Pearson's χ -square. It led to a R2 of 0.74 (RMSE: 0.80) against the validation dataset. While its validation went fast

  13. Remote sensing of LAI, chlorophyll and leaf nitrogen pools of crop- and grasslands in five European landscapes

    NASA Astrophysics Data System (ADS)

    Boegh, E.; Houborg, R.; Bienkowski, J.; Braban, C. F.; Dalgaard, T.; van Dijk, N.; Dragosits, U.; Holmes, E.; Magliulo, V.; Schelde, K.; Di Tommasi, P.; Vitale, L.; Theobald, M. R.; Cellier, P.; Sutton, M.

    2012-08-01

    Leaf nitrogen and leaf surface area influence the exchange of gases between terrestrial ecosystems and the atmosphere, and they play a significant role in the global cycles of carbon, nitrogen and water. Remote sensing data from satellites can be used to estimate leaf area index (LAI), leaf chlorophyll (CHLl) and leaf nitrogen density (Nl). However, methods are often developed using plot scale data and not verified over extended regions that represent a variety of soil spectral properties and canopy structures. In this paper, field measurements and high spatial resolution (10-20 m) remote sensing images acquired from the HRG and HRVIR sensors aboard the SPOT satellites were used to assess the predictability of LAI, CHLl and Nl. Five spectral vegetation indices (SVIs) were used (the Normalized Difference Vegetation index, the Simple Ratio, the Enhanced Vegetation Index-2, the Green Normalized Difference Vegetation Index, and the green Chlorophyll Index) together with the image-based inverse canopy radiative transfer modelling system, REGFLEC (REGularized canopy reFLECtance). While the SVIs require field data for empirical model building, REGFLEC can be applied without calibration. Field data measured in 93 fields within crop- and grasslands of five European landscapes showed strong vertical CHLl gradient profiles in 20% of fields. This affected the predictability of SVIs and REGFLEC. However, selecting only homogeneous canopies with uniform CHLl distributions as reference data for statistical evaluation, significant (p < 0.05) predictions were achieved for all landscapes, by all methods. The best performance was achieved by REGFLEC for LAI (r2=0.7; rmse = 0.73), canopy chlorophyll content (r2=0.51; rmse = 439 mg m-2) and canopy nitrogen content (r2 = 0.53; rmse = 2.21 g m-2). Predictabilities of SVIs and REGFLEC simulations generally improved when constrained to single land use categories (wheat, maize, barley, grass) across the European landscapes, reflecting

  14. Remote sensing of LAI, chlorophyll and leaf nitrogen pools of crop- and grasslands in five European landscapes

    NASA Astrophysics Data System (ADS)

    Boegh, E.; Houborg, R.; Bienkowski, J.; Braban, C. F.; Dalgaard, T.; van Dijk, N.; Dragosits, U.; Holmes, E.; Magliulo, V.; Schelde, K.; Di Tommasi, P.; Vitale, L.; Theobald, M. R.; Cellier, P.; Sutton, M. A.

    2013-10-01

    Leaf nitrogen and leaf surface area influence the exchange of gases between terrestrial ecosystems and the atmosphere, and play a significant role in the global cycles of carbon, nitrogen and water. The purpose of this study is to use field-based and satellite remote-sensing-based methods to assess leaf nitrogen pools in five diverse European agricultural landscapes located in Denmark, Scotland (United Kingdom), Poland, the Netherlands and Italy. REGFLEC (REGularized canopy reFLECtance) is an advanced image-based inverse canopy radiative transfer modelling system which has shown proficiency for regional mapping of leaf area index (LAI) and leaf chlorophyll (CHLl) using remote sensing data. In this study, high spatial resolution (10-20 m) remote sensing images acquired from the multispectral sensors aboard the SPOT (Satellite For Observation of Earth) satellites were used to assess the capability of REGFLEC for mapping spatial variations in LAI, CHLland the relation to leaf nitrogen (Nl) data in five diverse European agricultural landscapes. REGFLEC is based on physical laws and includes an automatic model parameterization scheme which makes the tool independent of field data for model calibration. In this study, REGFLEC performance was evaluated using LAI measurements and non-destructive measurements (using a SPAD meter) of leaf-scale CHLl and Nl concentrations in 93 fields representing crop- and grasslands of the five landscapes. Furthermore, empirical relationships between field measurements (LAI, CHLl and Nl and five spectral vegetation indices (the Normalized Difference Vegetation Index, the Simple Ratio, the Enhanced Vegetation Index-2, the Green Normalized Difference Vegetation Index, and the green chlorophyll index) were used to assess field data coherence and to serve as a comparison basis for assessing REGFLEC model performance. The field measurements showed strong vertical CHLl gradient profiles in 26% of fields which affected REGFLEC performance as well

  15. Draft Genome Sequence of Salmonella enterica subsp. enterica Serovar Bardo Strain CRJJGF_00099 (Phylum Gammaproteobacteria)

    PubMed Central

    Gupta, Sushim K.; McMillan, Elizabeth A.; Jackson, Charlene R.; Desai, Prerak T.; Porwollik, Steffen; McClelland, Michael; Hiott, Lari M.; Humayoun, Shaheen B.

    2016-01-01

    Here, we report a 4.87-Mbp draft genome sequence of the multidrug-resistant (MDR) Salmonella enterica subsp. enterica serovar Bardo strain CRJJGF_00099, isolated from dairy cattle in 2005. PMID:27634995

  16. Interlaboratory Agreement of Pulsed-Field Gel Electrophoresis Identification of Leptospira Serovars

    PubMed Central

    Mende, Katrin; Galloway, Renee L.; Becker, Sara J.; Beckius, Miriam L.; Murray, Clinton K.; Hospenthal, Duane R.

    2013-01-01

    Leptospirosis may be caused by > 250 Leptospira serovars. Serovar classification is a complex task that most laboratories cannot perform. We assessed the interlaboratory reproducibility of a pulsed-field gel electrophoresis (PFGE) identification technique developed by the Centers for Disease Control and Prevention (CDC). Blinded exchange of 93 Leptospiraceae strains occurred between San Antonio Military Medical Center (SAMMC) and the CDC. PFGE was performed and gel images were analyzed and compared with patterns present in each laboratory's database (CDC database: > 800 strain patterns; SAMMC database: > 300 strain patterns). Overall, 93.7% (74 of 79) of strains present in each receiving laboratory's database were correctly identified. Five isolates were misidentified, and two isolates did not match serovar PFGE patterns in the receiving laboratory's database. Patterns for these seven isolates were identical between laboratories; four serovars represented misidentified reference strains. The PFGE methodology studied showed excellent interlaboratory reproducibility, enabling standardization and data sharing between laboratories. PMID:23817329

  17. Protective effect of Lai Fu Cheng Qi decoction on severe acute pancreatitis-induced myocardial injury in a rat model.

    PubMed

    Li, Nan; Tian, Ying; Wang, Chunli; Zhang, Peng; You, Shengyi

    2015-04-01

    The aim of the present study was to evaluate the effects of Lai Fu Cheng Qi decoction on myocardial injury in rats with severe acute pancreatitis (SAP). In total, 30 rats were randomly divided into sham, SAP and decoction treatment groups. SAP was induced by a retrograde pancreatic duct injection of 5% sodium taurocholate in the SAP and decoction treatment groups. Rats in decoction treatment group also received intragastric administration of Lai Fu Cheng Qi decoction. The serum levels of creatine kinase isoenzyme (CK-MB) and lactate dehydrogenase (LDH) were detected using an automatic biochemical analyzer. In addition, myocardial Na(+)-K(+)-ATPase activity was analyzed using a spectrophotometric method and the mitochondrial membrane potential was measured by flow cytometry. Myocardial apoptosis was assessed using a TUNEL assay and pathological changes to the heart and pancreas were detected by hematoxylin and eosin staining. Compared with the rats in the sham group, rats in the SAP and decoction treatment groups exhibited significantly higher levels of serum CK-MB and LDH, apoptosis index and pathological scores, and had significantly lower levels of Na(+)-K(+)-ATPase activity and mitochondrial membrane potential. However, when compared with the SAP group, the serum levels of CK-MB and LDH, the pathological scores of the pancreas and heart, and the myocardial cell apoptosis index in the decoction treatment group were significantly lower. Furthermore, the Na(+)-K(+)-ATPase activity and mitochondrial membrane potential were significantly increased in the decoction treatment group when compared with the SAP group. Therefore, Lai Fu Cheng Qi decoction was shown to exert a protective effect on myocardial injury induced by SAP in rats.

  18. Serovar identification, antimicrobial sensitivity, and virulence of Avibacterium paragallinarum isolated from chickens in Thailand.

    PubMed

    Chukiatsiri, Kridda; Sasipreeyajan, Jiroj; Blackall, Patrick J; Yuwatanichsampan, Sommai; Chansiripornchai, Niwat

    2012-06-01

    Avibacterium paragallinarum causes infectious coryza in chickens, an acute respiratory disease that has worldwide economic significance. The objectives of this study were to determine the serovars, antimicrobial resistance, and pathogenicity of A. paragallinarum isolated from chickens in Thailand. Eighteen field isolates of A. paragallinarum were confirmed by PCR. When examined by serotyping in a hemagglutination inhibition test, 10 isolates were serovar A, five isolates were serovar B, and three isolates were serovar C. The susceptibility of the isolates to 16 antimicrobial agents was tested by a disk diffusion method. All isolates were susceptible to amoxicillin-clavulanic acid. There was a high level of resistance to lincomycin and erythromycin. All isolates were resistant to cloxacillin and neomycin. A study of bacterial entry into, and survival within, chicken macrophages showed variation between isolates but no clear connection to serovar. A virulence test was performed by challenging 4-wk-old layers via the nasal route with 400 dl of bacteria (10(8) colony-forming units/ml). Clinical signs were observed daily for 7 days, and the birds were subjected to a postmortem necropsy at 7 days postchallenge. All 18 field isolates caused the typical clinical signs of infectious coryza and could be re-isolated at 7 days after challenge. There was no significant difference in the clinical scores of the isolates except that two isolates (112179 and 102984, serovars A and B, respectively) gave a significantly higher score than did isolate CMU1009 (a serovar A isolate). No correlation between serovar and severity of clinical signs was found.

  19. Comparative Genomic Analyses of Transport Proteins Encoded Within the Genomes of Leptospira Species

    PubMed Central

    Buyuktimkin, Bora; Saier, Milton H.

    2015-01-01

    Select species of the bacterial genus Leptospira are causative agents of leptospirosis, an emerging global zoonosis affecting nearly one million people worldwide annually. We examined two Leptospira pathogens, L. interrogans serovar Lai str. 56601 and L. borgpetersenii serovar Hardjo-bovis str. L550, as well as the free-living leptospiral saprophyte, L. biflexa serovar Patoc str. ‘Patoc 1 (Ames)’. The transport proteins of these leptospires were identified and compared using bioinformatics to gain an appreciation for which proteins may be related to pathogenesis and saprophytism. L. biflexa possesses a disproportionately high number of secondary carriers for metabolite uptake and environmental adaptability as well as an increased number of inorganic cation transporters providing ionic homeostasis and effective osmoregulation in a rapidly changing environment. L. interrogans and L. borgpetersenii possess far fewer transporters, but those that they have are remarkably similar, with near-equivalent representation in most transporter families. These two Leptospira pathogens also possess intact sphingomyelinases, holins, and virulence-related outer membrane porins. These virulence-related factors, in conjunction with decreased transporter substrate versatility, indicate that pathogenicity was accompanied by progressively narrowing ecological niches and the emergence of a limited set of proteins responsible for host invasion. The variability of host tropism and mortality rates by infectious leptospires suggests that small differences in individual sets of proteins play important physiological and pathological roles. PMID:26247102

  20. Amino acid sequences of proteins from Leptospira serovar pomona.

    PubMed

    Alves, S F; Lefebvre, R B; Probert, W

    2000-01-01

    This report describes a partial amino acid sequences from three putative outer envelope proteins from Leptospira serovar pomona. In order to obtain internal fragments for protein sequencing, enzymatic and chemical digestion was performed. The enzyme clostripain was used to digest the proteins 32 and 45 kDa. In situ digestion of 40 kDa molecular weight protein was accomplished using cyanogen bromide. The 32 kDa protein generated two fragments, one of 21 kDa and another of 10 kDa that yielded five residues. A fragment of 24 kDa that yielded nineteen residues of amino acids was obtained from 45 kDa protein. A fragment with a molecular weight of 20 kDa, yielding a twenty amino acids sequence from the 40 kDa protein.

  1. Salmonella enterica serovar Enteritidis, England and Wales, 1945-2011.

    PubMed

    Lane, Christopher R; LeBaigue, Susan; Esan, Oluwaseun B; Awofisyo, Adedoyin A; Adams, Natalie L; Fisher, Ian S T; Grant, Kathie A; Peters, Tansy M; Larkin, Lesley; Davies, Robert H; Adak, Goutam K

    2014-07-01

    In England and Wales, the emergence of Salmonella enterica serovar Enteritidis resulted in the largest and most persistent epidemic of foodborne infection attributable to a single subtype of any pathogen since systematic national microbiological surveillance was established. We reviewed 67 years of surveillance data to examine the features, underlying causes, and overall effects of S. enterica ser. Enteritidis. The epidemic was associated with the consumption of contaminated chicken meat and eggs, and a decline in the number of infections began after the adoption of vaccination and other measures in production and distribution of chicken meat and eggs. We estimate that >525,000 persons became ill during the course of the epidemic, which caused a total of 6,750,000 days of illness, 27,000 hospitalizations, and 2,000 deaths. Measures undertaken to control the epidemic have resulted in a major reduction in foodborne disease in England and Wales.

  2. Osteomyelitis caused by Salmonella enterica serovar derby in boa constrictor.

    PubMed

    de Souza, Suyene O; Casagrande, Renata A; Guerra, Priscila R; Cruz, Cláudio E F; Veit, Evandro; Cardoso, Marisa R I; Driemeier, David

    2014-09-01

    After demonstrating chronic weight loss, prostration, and muscle flaccidness, a captive-bred 9-mo-old boa constrictor (Boa constrictor constrictor) died and was submitted for necropsy. Along the spinal column there were multiple, yellowish white, macroscopic nodules of 1-5 mm in diameter in the ventral side of the vertebral body and in the intervertebral spaces. Severe multifocal necrotizing osteomyelitis associated with granulomatous inflammation was the main histologic finding in the vertebral column. In the liver, there was discrete but similar granulomatous changes. Positive anti-Salmonella immunostaining was observed in the spinal column and in the liver. Salmonella enterica serovar Derby was isolated from fragments of the spinal column. These bacteria are important cause of disease in captive reptiles.

  3. Salmonella enterica serovar Typhi and the pathogenesis of typhoid fever.

    PubMed

    Dougan, Gordon; Baker, Stephen

    2014-01-01

    Salmonella enterica serovar Typhi, the cause of typhoid, is host restricted to humans. S. Typhi has a monophyletic population structure, indicating that typhoid in humans is a relatively new disease. Antimicrobial usage is reshaping the current S. Typhi global population and may be driving the emergence of a specific haplotype, H58, that is well adapted to transmission in modern settings and is able to resist antimicrobial killing more efficiently than other S. Typhi. Evidence gathered through genomics and functional studies using the mouse and in vitro cell systems, together with clinical investigations, has provided insight into the mechanisms that underpin the pathogenesis of human typhoid and host restriction. Here we review the latest scientific advances in typhoid research and discuss how these novel approaches are changing our understanding of the disease.

  4. The emergence of Leptospira borgpetersenii serovar Arborea as the dominant infecting serovar following the summer of natural disasters in Queensland, Australia 2011.

    PubMed

    Wynwood, S J; Craig, S B; Graham, G C; Blair, B R; Burns, M A; Weier, S L; Collet, T A; McKay, D B

    2014-06-01

    The following research reports the emergence of Leptospira borgpetersenii serovar Arborea as the dominant infecting serovar following the summer of disasters and the ensuing clean up in Queensland, Australia during 2011. For the 12 month period (1 January to 31 December) L. borgpetersenii serovar Arborea accounted for over 49% of infections. In response to a flooding event public health officials need to issue community wide announcements warning the population about the dangers of leptospirosis and other water borne diseases. Communication with physicians working in the affected community should also be increased to update physicians with information such as clinical presentation of leptospirosis and other waterborne diseases. These recommendations will furnish public health officials with considerations for disease management when dealing with future disaster management programs.

  5. Novel haemolysins of Salmonella enterica spp. enterica serovar Gallinarum.

    PubMed

    Agrawal, Ravi Kant; Singh, B R; Babu, N; Chandra, Mudit

    2005-07-01

    Haemolysins of Salmonella are important due to their probable role in pathogenesis of systemic salmonellosis and use in sub-serovar level typing. The present study was undertaken to determine haemolytic potential of Salmonella Gallinarum strains through phenotypic and genotypic methods. Amplification of haemolysin gene (clyA) and cytolysin gene (slyA) was attempted in order to determine their role in haemolysin production. Study on 94 strains of S. Gallinarum revealed the production of two types of haemolysis viz., beneath the colony haemolysis (BCH) or contact haemolysis and clear zone haemolysis (CZH). Haemolysis was observed on blood agar prepared with blood of cattle, buffalo, sheep, goat, horse, rabbit, guinea pig, fowl, and human blood group A, B, AB and O. Although, haemolysis was also observed on blood agar prepared with whole blood, clarity of zone was more evident on blood agar made from washed erythrocytes. Clear zone haemolysis was best observed on blood agar prepared with washed erythrocytes of goat and a total of 12% (11 of 94) S. Gallinarum strains under study produced CZH on it. The clyA gene could not be detected in any of the 94 strains under study, while slyA gene could be amplified uniformly irrespective of haemolytic potential (CZH) and haemolytic pattern (BCH) of the strains. The study suggested that the two types of haemolysis (CZH and BCH) observed among S. Gallinarum strains may not be due to either slyA or clyA gene products and thus there may be some other gene responsible for haemolytic trait in Gallinarum serovar. Different haemolytic patterns of strains under study indicated multiplicity of haemolysins in S. Gallinarum.

  6. Intracellular Voyeurism: Examining the Modulation of Host Cell Activities bySalmonella enterica Serovar Typhimurium.

    PubMed

    Szeto, Jason; Brumell, John H

    2005-11-01

    Salmonella spp. can infect host cells by gaining entry through phagocytosis or by inducing host cell membrane ruffling that facilitates bacterial uptake. With its wide host range, Salmonella enterica serovar Typhimurium has proven to be an important model organism for studying intracellular bacterial pathogenesis. Upon entry into host cells, serovar Typhimurium typically resides within a membrane-bound compartment termed the Salmonella-containing vacuole (SCV). From the SCV, serovar Typhimurium can inject several effector proteins that subvert many normal host cell systems, including endocytic trafficking, cytoskeletal rearrangements, lipid signaling and distribution, and innate and adaptive host defenses. The study of these intracellular events has been made possible through the use of various imaging techniques, ranging from classic methods of transmission electron microscopy to advanced livecell fluorescence confocal microscopy. In addition, DNA microarrays have now been used to provide a "snapshot" of global gene expression in serovar Typhimurium residing within the infected host cell. This review describes key aspects of Salmonella-induced subversion of host cell activities, providing examples of imaging that have been used to elucidate these events. Serovar Typhimurium engages specific host cell machinery from initial contact with the host cell to replication within the SCV. This continuous interaction with the host cell has likely contributed to the extensive arsenal that serovar Typhimurium now possesses, including two type III secretion systems, a range of ammunition in the form of TTSS effectors, and a complex genetic regulatory network that coordinates the expression of hundreds of virulence factors.

  7. Presence of antibodies against Leptospira serovars in Chaetophractus villosus (Mammalia, Dasypodidae), La Pampa province, Argentina.

    PubMed

    Kin, Marta S; Brihuega, Bibiana; Fort, Marcelo; Delgado, Fernando; Bedotti, Daniel; Casanave, Emma B

    2015-01-01

    Leptospirosis is a zoonosis of worldwide distribution. The aim of this study was to examine the presence of antibodies against 21 Leptospira reactive serovars in Chaetophractus villosus in La Pampa province, Argentina, using the microscopic agglutination test (MAT). Pathologic changes compatible with leptospirosis and in situ detection of the agent by immunohistochemistry were studied in 24 and 3 individuals respectively. Only 35/150 (23.3%) serum samples had antibodies against Leptospira sp. Six percent of the samples reacted with serovar Canicola, 4.7% with serovar Castellonis, 1.3% with serovar Icterohemorrhagieae and 0.7% with serovar Hardjo. Sixteen (10.6%) serum samples agglutinated with Castellonis-Icterohemorrhagiae and Canicola-Castellonis serovars, both with 4.7%, and Canicola-Hardjo and Castellonis-Canicola-Icterohemorrhagiae both with 0.6%. Fourteen animals had variable degrees of lesions, which were more severe in animals with higher serological titers (3200), and Leptospira sp. was detected in 3 animals by immunohistochemistry. These results represent the first record of the presence of Leptospira in C. villosus in La Pampa.

  8. Leptospira Protein Expression During Infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We are characterizing protein expression in vivo during experimental leptospirosis using immunofluorescence microscopy. Coding regions for several proteins were identified through analysis of Leptospira interrogans serovar Copenhageni and L. borgpetersenii serovar Hardjo genomes. In addition, codi...

  9. Expansion of the in vitro assay for Leptospira potency testing to other Serovars: Case study with Leptospira hardjo

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Code for Federal Regulations (9 CFR 113:101-104) specifies how vaccine potency is evaluated in a hamster model for evaluation of leptospiral vaccines against pomona, icterohaemorrhagiae, canicola, and grippotyphosa serotypes of Leptospira interrogans. There are several issues which complicate th...

  10. Image based remote sensing method for modeling black-eyed beans (Vigna unguiculata) Leaf Area Index (LAI) and Crop Height (CH) over Cyprus

    NASA Astrophysics Data System (ADS)

    Papadavid, Giorgos; Fasoula, Dionysia; Hadjimitsis, Michael; Skevi Perdikou, P.; Hadjimitsis, Diofantos

    2013-03-01

    In this paper, Leaf Area Index (LAI) and Crop Height (CH) are modeled to the most known spectral vegetation index — NDVI — using remotely sensed data. This approach has advantages compared to the classic approaches based on a theoretical background. A GER-1500 field spectro-radiometer was used in this study in order to retrieve the necessary spectrum data for estimating a spectral vegetation index (NDVI), for establishing a semiempirical relationship between black-eyed beans' canopy factors and remotely sensed data. Such semi-empirical models can be used then for agricultural and environmental studies. A field campaign was undertaken with measurements of LAI and CH using the Sun-Scan canopy analyzer, acquired simultaneously with the spectroradiometric (GER1500) measurements between May and June of 2010. Field spectroscopy and remotely sensed imagery have been combined and used in order to retrieve and validate the results of this study. The results showed that there are strong statistical relationships between LAI or CH and NDVI which can be used for modeling crop canopy factors (LAI, CH) to remotely sensed data. The model for each case was verified by the factor of determination. Specifically, these models assist to avoid direct measurements of the LAI and CH for all the dates for which satellite images are available and support future users or future studies regarding crop canopy parameters.

  11. Image based remote sensing method for modeling black-eyed beans ( Vigna unguiculata) Leaf Area Index (LAI) and Crop Height (CH) over Cyprus

    NASA Astrophysics Data System (ADS)

    Papadavid, Giorgos; Fasoula, Dionysia; Hadjimitsis, Michael; Skevi Perdikou, P.; Hadjimitsis, Diofantos G.

    2013-03-01

    In this paper, Leaf Area Index (LAI) and Crop Height (CH) are modeled to the most known spectral vegetation index — NDVI — using remotely sensed data. This approach has advantages compared to the classic approaches based on a theoretical background. A GER-1500 field spectro-radiometer was used in this study in order to retrieve the necessary spectrum data for estimating a spectral vegetation index (NDVI), for establishing a semiempirical relationship between black-eyed beans' canopy factors and remotely sensed data. Such semi-empirical models can be used then for agricultural and environmental studies. A field campaign was undertaken with measurements of LAI and CH using the Sun-Scan canopy analyzer, acquired simultaneously with the spectroradiometric (GER1500) measurements between May and June of 2010. Field spectroscopy and remotely sensed imagery have been combined and used in order to retrieve and validate the results of this study. The results showed that there are strong statistical relationships between LAI or CH and NDVI which can be used for modeling crop canopy factors (LAI, CH) to remotely sensed data. The model for each case was verified by the factor of determination. Specifically, these models assist to avoid direct measurements of the LAI and CH for all the dates for which satellite images are available and support future users or future studies regarding crop canopy parameters.

  12. Urogenital Chlamydia trachomatis Serovars in Men and Women with a Symptomatic or Asymptomatic Infection: an Association with Clinical Manifestations?

    PubMed Central

    Morré, S. A.; Rozendaal, L.; van Valkengoed, I. G. M.; Boeke, A. J. P.; van Voorst Vader, P. C.; Schirm, J.; de Blok, S.; van den Hoek, J. A. R.; van Doornum, G. J. J.; Meijer, C. J. L. M.; van den Brule, A. J. C.

    2000-01-01

    To determine whether certain Chlamydia trachomatis serovars are preferentially associated with a symptomatic or an asymptomatic course of infection, C. trachomatis serovar distributions were analyzed in symptomatically and asymptomatically infected persons. Furthermore, a possible association between C. trachomatis serovars and specific clinical symptoms was investigated. C. trachomatis-positive urine specimens from 219 asymptomatically infected men and women were obtained from population-based screening programs in Amsterdam. Two hundred twenty-one C. trachomatis-positive cervical and urethral swabs from symptomatically and asymptomatically infected men and women were obtained from several hospital-based departments. Serovars were determined using PCR-based genotyping, i.e., restriction fragment length polymorphism analysis of the nested-PCR-amplified omp1 gene. The most prevalent C. trachomatis serovars, D, E, and F, showed no association with either a symptomatic or asymptomatic course of infection. The most prominent differences found were (i) the association of serovar Ga with symptoms in men (P = 0.0027), specifically, dysuria (P < 0.0001), and (ii) detection of serovar Ia more often in asymptomatically infected people (men and women) (P = 0.035). Furthermore, in women, serovar K was associated with vaginal discharge (P = 0.002) and serovar variants were found only in women (P = 0.045). PMID:10834991

  13. The relationship of Hyper-spectral Vegetation Indices with LAI over the growth cycle of Wheat and Chickpea at 3nm spectral resolution

    NASA Astrophysics Data System (ADS)

    Gupta, R.; Vijayan, D.; Prasad, T.

    Using 3 nm observations over wheat and chickpea, hyperspectral indices, hNDVI= [(R 774-R677)/(R774+R677)], hRVI=R7 7 4/R 677 and TM bandwidths based NDVI, RVI and SAVI were computed. Pigment specific ratios (PSR) with reflectance at 800 nm (R800) as numerator were computed for Chlorophyll-a (PSR a= R800 /R 680 ) , Chlorophyll-b (PSR b = R800 /R 635) and Chlorophyll- Carotenoid (PSRc= R800 /R 470 ) . Structure intensive pigment indices (SIPI) given by SIPIa=(R 800 -R 445)/(R 800 -R6 8 0) and SIPIb =[(R 800 -R445)/(R 680 -R4 4 5)] were computed. Acceptable confidence level (r2 in 0.90-0.96 and 0.86-0.91 for all the above mentioned ratios and normalized difference indices, respectively) in correlation of these indices with LAI for wheat was observed when LAI for growth and decline phases were regressed separately; for ratio and normalized indices for chickpea, the r2 (for relationship with LAI) was in 0.85-0.97 range for growth phase and in 0.64-0.85 range for decline phase. In case of chickp ea, the leaves becoming yellow do not fall or undergo change in interaction cross-section to incident light; thus, LAI does not change though spectral indices will change. The r2 for the correlations of LAI for wheat, with TMRVI, PSR a, PSR b , PSRc were in 0.92-0.96 range; with TM NDVI and TM SAVI r 2 were in 0.90-0.91 range and with SIPIa and SIPIb r2 were in 0.67-0.78 range. Correlations were also computed for LAI with all possible ratio indices as well as normalized indices using 3 nm bandwidths dat a sets in 368 to 950 nm region. The correlation coefficients of LAI, for wheat, with ratios of 729-950 nm spectral region to 564-693 nm spectral region were in 0.95-0.99 range for growth phase (of LAI) and in 0.96-0.968 range during declining phase (of LAI) while for chickpea the correlations were in 0.86-0.90 range for growth phase (of LAI) and 0.91-0.96 range during declining phase (of LAI) for the ratios of 711-798 nm spectral region to 673 - 685 nm (growth phase)/693-708 nm

  14. A serological survey of Leptospira interrogans serotype pomona in Alberta and Saskatchewan striped skunks and possible transmission between cattle and skunks.

    PubMed

    Schowalter, D B; Chalmers, G A; Johnson, G R; Gunson, J R; Wynnyk, W P

    1981-10-01

    The range of known occurrence of Leptospira interrogans serotype pomona is extended to Alberta in striped skunks (Mephitis mephitis); no evidence of L. sejroe was found. Reacting sera from skunks were confined to the southern portion of Alberta and adjacent Saskatchewan, although a number of reactors were found sufficiently further north in Saskatchewan suggesting that a different mode of infection may be functioning there. Of 95 skunk sera from near a dairy farm infected with serotype pomona 40% were reactors. Of 438 skunk sera from other areas only 5.7% were reactors; that difference was suggestive of transmission from cattle to skunks on the dairy farm. Of 22 skunk sera collected near the dairy farm in summer none were reactors, whereas 52% of skunk sera taken the previous and following winters were. That seasonal difference was not evident among sera from other locations.

  15. Expression of leptospiral immunoglobulin-like protein by Leptospira interrogans and evaluation of its diagnostic potential in a kinetic ELISA.

    PubMed

    Palaniappan, Raghavan U M; Chang, Yung-Fu; Hassan, Fahad; McDonough, Sean P; Pough, Margaret; Barr, Stephen C; Simpson, Kenneth W; Mohammed, Hussni O; Shin, Sang; McDonough, Patrick; Zuerner, Richard L; Qu, Jiaxin; Roe, Bruce

    2004-10-01

    The search for novel antigens suitable for improved vaccines and diagnostic reagents against leptospirosis led to the identification of LigA and LigB. LigA and LigB expression were not detectable at the translation level but were detectable at the transcription level in leptospires grown in vitro. Lig genes were present in pathogenic serovars of Leptospira, but not in non-pathogenic Leptospira biflexa. The conserved and variable regions of LigA and LigB (Con, VarA and VarB) were cloned, expressed and purified as GST-fusion proteins. Purified recombinant LigA and LigB were evaluated for their diagnostic potential in a kinetic ELISA (KELA) using sera from vaccinated and microscopic agglutination test (MAT)-positive dogs. Sera from vaccinated dogs showed reactivity to whole-cell antigens of leptospires but did not show reactivity in the KELA assay with recombinant antigens, suggesting a lack of antibodies to Lig proteins in the vaccinated animals. The diagnostic potential of recombinant Lig antigens in the KELA assay was evaluated by using 67 serum samples with MAT > or =1600, which showed reactivity of 76, 41 and 35% to rConA, rVarA and rVarB, respectively. These findings suggest that recombinant antigen to the conserved region of LigA and LigB can differentiate between vaccinated and naturally infected animals.

  16. The relationship of hyper-spectral vegetation indices with leaf area index (LAI) over the growth cycle of wheat and chickpea at 3 nm spectral resolution

    NASA Astrophysics Data System (ADS)

    Gupta, R. K.; Vijayan, D.; Prasad, T. S.

    2006-01-01

    Hyperspectral ratio and normalized difference vegetation indices were computed from the 3 nm bandwidth ground-based spectral data taken in 400-950 nm wave length region over the crop growth cycle (CGC) of wheat and chickpea. Synthesized broad band Landsat TM-RVI, TM-NDVI and TM-SAVI were also computed using this narrow bandwidth spectral observations. Regression analysis was carried out for these indices with leaf area index (LAI) for wheat and chickpea over CGC and the r2 values were found poor in 0.2-0.53 range for wheat and in 0.41-0.82 range for chickpea. Significant relationship with LAI were found for wheat ( r2 in 0.86-0.97 range) when growth and decline phases were analyzed independently. Here, r2 values for chickpea were less than that for wheat. The high difference in rate of change of slope for hRVI is a good discriminator for high ET (wheat) and low ET (chickpea) crops. To find out the potential hyperspectral ratios and normalized difference indices that could provide strong relationship with LAI, a correlation-based analysis was carried out for LAI with all the possible combinations of ratios and normalized difference indices in 400-950 nm region (at 3 nm spectral interval) independently for growth and decline phases of LAI and found that in addition to traditional near-IR and red pairs, the pairs within near-IR, near-IR and visible extending to near-IR were also significantly related to LAI.

  17. Population Structure of Salmonella enterica Serovar 4,[5],12:b:− Strains and Likely Sources of Human Infection

    PubMed Central

    Toboldt, Anne; Tietze, Erhard; Helmuth, Reiner; Junker, Ernst; Fruth, Angelika

    2013-01-01

    Salmonella enterica serovar 4,[5],12:b:− is a monophasic serovar not able to express the second-phase flagellar antigen (H2 antigen). In Germany, the serovar is occasionally isolated from poultry, reptiles, fish, food, and humans. In this study, a selection of 67 epidemiologically unrelated Salmonella enterica serovar 4,[5],12:b:− strains isolated in Germany between 2000 and 2011 from the environment, animal, food, and humans was investigated by phenotypic and genotypic methods to better understand the population structure and to identify potential sources of human infections. Strains of this monophasic serovar were highly diverse. Within the 67 strains analyzed, we identified 52 different pulsed-field gel electrophoresis XbaI profiles, 12 different multilocus sequence types (STs), and 18 different pathogenicity array types. The relatedness of strains based on the pathogenicity gene repertoire (102 markers tested) was in good agreement with grouping by MLST. S. enterica serovar 4,[5],12:b:− is distributed across multiple unrelated eBurst groups and consequently is highly polyphyletic. Two sequence types (ST88 and ST127) were linked to S. enterica serovar Paratyphi B (d-tartrate positive), two single-locus variants of ST1583 were linked to S. enterica serovar Abony, and one sequence type (ST1484) was associated with S. enterica serovar Mygdal, a recently defined, new serovar. From the characterization of clinical isolates and those of nonhuman origin, it can be concluded that the potential sources of sporadic human infections with S. enterica serovar 4,[5],12:b:− most likely are mushrooms, shellfish/fish, and poultry. PMID:23793625

  18. Differences in innate immune responses (in vitro) to HeLa cells infected with nondisseminating serovar E and disseminating serovar L2 of Chlamydia trachomatis.

    PubMed

    Dessus-Babus, Sophie; Darville, Toni L; Cuozzo, Francis P; Ferguson, Kaethe; Wyrick, Priscilla B

    2002-06-01

    The inflammatory response associated with Chlamydia trachomatis genital infections is thought to be initiated by the release of proinflammatory cytokines from infected epithelial cells. This study focuses on the interactions between C. trachomatis-infected HeLa cells and immune cells involved in the early stages of infection, i.e., neutrophils and macrophages. First, we showed that the expression of interleukin-11 (IL-11), an anti-inflammatory cytokine mainly active on macrophages, was upregulated at the mRNA level in the genital tracts of infected mice. Second, incubation of differentiated THP-1 (dTHP-1) cells or monocyte-derived macrophages (MdM) with basal culture supernatants from C. trachomatis serovar E- or serovar L2-infected HeLa cells resulted in macrophage activation with a differential release of tumor necrosis factor alpha (TNF-alpha) and upregulation of indoleamine 2,3-deoxygenase (IDO) but not of Toll-like receptor 2 and 4 mRNA expression. Third, coculture of infected HeLa cells with dTHP-1 cells resulted in a reduction in chlamydial growth, which was more dramatic for serovar E than for L2 and which was partially reversed by the addition of anti-TNF-alpha antibodies for serovar E or exogenous tryptophan for both serovars but was not reversed by the addition of superoxide dismutase or anti-IL-8 or anti-IL-1beta antibodies. A gamma interferon-independent IDO mRNA upregulation was also detected in dTHP-1 cells from infected cocultures. Lastly, with a two-stage coculture system, we found that (i) supernatants from neutrophils added to the apical side of infected HeLa cell cultures were chlamydicidal and induced MdM to express antichlamydial activity and (ii) although polymorphonuclear leukocytes released more proinflammatory cytokines in response to serovar E- than in response to L2-infected cells, MdM were strongly activated by serovar L2 infection, indicating that the early inflammatory response generated with a nondisseminating or a disseminating

  19. Map-Based Comparative Genomic Analysis of Virulent Haemophilus Parasuis Serovars 4 and 5

    PubMed Central

    Lawrence, Paulraj; Bey, Russell

    2015-01-01

    Haemophilus parasuis is a commensal bacterium of the upper respiratory tract of healthy pigs. However, in conjunction with viral infections in immunocompromised animals H. parasuis can transform into a pathogen that is responsible for causing Glasser's disease which is typically characterized by fibrinous polyserositis, polyarthritis, meningitis and sometimes acute pneumonia and septicemia in pigs. Haemophilus parasuis serovar 5 is highly virulent and more frequently isolated from respiratory and systemic infection in pigs. Recently a highly virulent H. parasuis serovar 4 was isolated from the tissues of diseased pigs. To understand the differences in virulence and virulence-associated genes between H. parasuis serovar 5 and highly virulent H. parasuis serovar 4 strains, a genomic library was generated by TruSeq preparation and sequenced on Illumina HiSeq 2000 obtaining 50 bp PE reads. A three-way comparative genomic analysis was conducted between two highly virulent H. parasuis serovar 4 strains and H. parasuis serovar 5. Haemophilus parasuis serovar 5 GenBank isolate SH0165 (GenBank accession number CP001321.1) was used as reference strain for assembly. Results of these analysis revealed the highly virulent H. parasuis serovar 4 lacks genes encoding for, glycosyl transferases, polysaccharide biosynthesis protein capD, spore coat polysaccharide biosynthesis protein C, polysaccharide export protein and sialyltransferase which can modify the lipopolysaccharide forming a short-chain LPS lacking O-specific polysaccharide chains often referred to as lipooligosaccharide (LOS). In addition, it can modify the outer membrane protein (OMP) structure. The lack of sialyltransferase significantly reduced the amount of sialic acid incorporated into LOS, a major and essential component of the cell wall and an important virulence determinant. These molecules may be involved in various stages of pathogenesis through molecular mimicry and by causing host cell cytotoxicity, reduced

  20. Circulating serovars of Leptospira in cart horses of central and southern Ethiopia and associated risk factors.

    PubMed

    Tsegay, K; Potts, A D; Aklilu, N; Lötter, C; Gummow, B

    2016-03-01

    Little work has been done on diseases of horses in Ethiopia or tropical regions of the world. Yet, Ethiopia has the largest horse population in Africa and their horses play a pivotal role in their economy as traction animals. A serological and questionnaire survey was therefore conducted to determine the circulating serovars of Leptospira and their association with potential risk factors in the cart horse population of Central and Southern Ethiopia. A total of 184 out of 418 cart horses from 13 districts had antibody titres of 1:100 or greater to at least one of 16 serovars of Leptospira species in Central and Southern Ethiopian horses. A significantly higher seropositivity (62.1%) was noted in horses from the highland agroecology followed by midland (44.4%) and lowland (39.8%). Serovar Bratislava (34.5%) was the predominant serovar followed by serovars Djasiman (9.8%), Topaz (5.98%) and Pomona (5.3%). Age and location proved to be associated with seropositive horses with older horses being more commonly affected and the districts of Ziway (Batu) (Apparent Prevalence (AP)=65.5%), Shashemene (AP=48.3%) and Sebeta (AP=41.4%) having the highest prevalence. Multivariable logistic regression found risk factors significantly associated with Leptospira seropositive horses were drinking river water (OR=2.8) and horses 7-12 years old (OR=5) and risk factors specifically associated with serovar Bratislava seropositive horses were drinking river water (OR=2.5), horses ≥13 years (OR=3.5) and the presence of dogs in adjacent neighbouring properties (OR=0.3). Dogs had a protective effect against seropositivity to serovars Bratislava and Djasiman, which may be due to their ability to control rodents. The high seroprevalence confirm that leptospirosis is endemic among horses of Central and Southern Ethiopia. The predominance of serovar Bratislava supports the idea that serovar Bratislava may be adapted to and maintained by the horse population of Central and Southern Ethiopia

  1. Complete Genome and Methylome Sequences of Salmonella enterica subsp. enterica Serovars Typhimurium, Saintpaul, and Stanleyville from the SARA/SARB Collection

    PubMed Central

    Yao, Kuan; Roberts, Richard J.; Allard, Marc W.

    2017-01-01

    ABSTRACT In this announcement, we report the complete genome and methylome sequences of three Salmonella enterica strains from the SARA and SARB collection: S. enterica subsp. enterica serovar Typhimurium (SARA13), S. enterica subsp. enterica serovar Saintpaul (SARA26), and S. enterica subsp. enterica serovar Stanleyville (SARB61). PMID:28302778

  2. Rapid multiplex PCR and Real-Time TaqMan PCR assays for detection of Salmonella enterica and the highly virulent serovars Choleraesuis and Paratyphi C

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica is a human pathogen with over 2,500 serovars characterized. S. enterica serovars Choleraesuis (Cs) and Paratyphi C (Pc) are two globally distributed serovars. We have developed a rapid molecular typing method to detect Cs and Pc in food samples by using a comparative genomics ap...

  3. Genomic Comparison of the Closely-Related Salmonella enterica Serovars Enteritidis, Dublin and Gallinarum

    PubMed Central

    Matthews, T. David; Schmieder, Robert; Silva, Genivaldo G. Z.; Busch, Julia; Cassman, Noriko; Dutilh, Bas E.; Green, Dawn; Matlock, Brian; Heffernan, Brian; Olsen, Gary J.; Farris Hanna, Leigh; Schifferli, Dieter M.; Maloy, Stanley; Dinsdale, Elizabeth A.; Edwards, Robert A.

    2015-01-01

    The Salmonella enterica serovars Enteritidis, Dublin, and Gallinarum are closely related but differ in virulence and host range. To identify the genetic elements responsible for these differences and to better understand how these serovars are evolving, we sequenced the genomes of Enteritidis strain LK5 and Dublin strain SARB12 and compared these genomes to the publicly available Enteritidis P125109, Dublin CT 02021853 and Dublin SD3246 genome sequences. We also compared the publicly available Gallinarum genome sequences from biotype Gallinarum 287/91 and Pullorum RKS5078. Using bioinformatic approaches, we identified single nucleotide polymorphisms, insertions, deletions, and differences in prophage and pseudogene content between strains belonging to the same serovar. Through our analysis we also identified several prophage cargo genes and pseudogenes that affect virulence and may contribute to a host-specific, systemic lifestyle. These results strongly argue that the Enteritidis, Dublin and Gallinarum serovars of Salmonella enterica evolve by acquiring new genes through horizontal gene transfer, followed by the formation of pseudogenes. The loss of genes necessary for a gastrointestinal lifestyle ultimately leads to a systemic lifestyle and niche exclusion in the host-specific serovars. PMID:26039056

  4. Physiological and Molecular Responses of Lactuca sativa to Colonization by Salmonella enterica Serovar Dublin▿

    PubMed Central

    Klerks, M. M.; van Gent-Pelzer, M.; Franz, E.; Zijlstra, C.; van Bruggen, A. H. C.

    2007-01-01

    This paper describes the physiological and molecular interactions between the human-pathogenic organism Salmonella enterica serovar Dublin and the commercially available mini Roman lettuce cv. Tamburo. The association of S. enterica serovar Dublin with lettuce plants was first determined, which indicated the presence of significant populations outside and inside the plants. The latter was evidenced from significant residual concentrations after highly efficient surface disinfection (99.81%) and fluorescence microscopy of S. enterica serovar Dublin in cross sections of lettuce at the root-shoot transition region. The plant biomass was reduced significantly compared to that of noncolonized plants upon colonization with S. enterica serovar Dublin. In addition to the physiological response, transcriptome analysis by cDNA amplified fragment length polymorphism analysis also provided clear differential gene expression profiles between noncolonized and colonized lettuce plants. From these, generally and differentially expressed genes were selected and identified by sequence analysis, followed by reverse transcription-PCR displaying the specific gene expression profiles in time. Functional grouping of the expressed genes indicated a correlation between colonization of the plants and an increase in expressed pathogenicity-related genes. This study indicates that lettuce plants respond to the presence of S. enterica serovar Dublin at physiological and molecular levels, as shown by the reduction in growth and the concurrent expression of pathogenicity-related genes. In addition, it was confirmed that Salmonella spp. can colonize the interior of lettuce plants, thus potentially imposing a human health risk when processed and consumed. PMID:17513585

  5. Innate immune control of Salmonella enterica serovar Typhimurium: mechanisms contributing to combating systemic Salmonella infection.

    PubMed

    Wick, Mary Jo

    2011-01-01

    Infections with Salmonella enterica serovars remain a serious problem worldwide. While serovar Typhi causes significant morbidity and mortality that is restricted to humans, serovar Typhimurium causes gastroenteritidis in humans and can also infect other animals. As mice with the susceptible Nramp1 locus get systemic infection with serovar Typhimurium, murine infection models using this serovar have been widely used to decipher the immune mechanisms required to survive systemic Salmonella infection. This review summarizes recent studies in murine infection models that have advanced our understanding of the events that occur during the first days after oral Salmonella infection. The pathways of bacterial penetration across the intestinal epithelium, bacterial spread to draining (mesenteric) lymph nodes and dissemination to systemic tissues is discussed. The response of myeloid cell populations, including dendritic cells, inflammatory monocytes and neutrophils, during the early stage of infection is also discussed. Finally, the mechanisms driving recruitment of myeloid cells to infected intestinal lymphoid tissues and what is known about Toll-like receptor signaling pathways in innate immunity to Salmonella infection is also discussed.

  6. Tissue colonization and circulating T lymphocytes in laying hens upon oral challenge with Salmonella enterica serovars.

    PubMed

    Balan, Kannan V; Bigley, Elmer C; Gaines, Dennis W; Babu, Uma S

    2016-12-01

    Evaluating the potential of Salmonella serovars for tissue colonization and egg contamination in laying hens is critical due to widespread consumption of poultry and egg-containing products. The 2009 FDA Egg Rule was implemented to target the eradication of Salmonella enterica Enteritidis (SE) from layers; however, other Salmonella serovars, such as Heidelberg (SH) and Typhimurium (ST), have also been associated with poultry-related outbreaks. We conducted this study to see if serovars other than SE could colonize in laying hens, cause egg contamination, and modulate circulating T-cell populations. Laying hens were orally gavaged with 10(7) colony forming units (CFU) of SE, SH, or ST and assessed for colonization in spleen, ovaries, and oviduct 10 d postchallenge. Splenic colonization was similar for all the serovars; however, colonization of ovaries and oviducts was significantly higher with SH compared to SE and ST. Furthermore, SH challenge resulted in egg contamination, while SE and ST did not result in contaminated eggs. Phenotypic evaluation of peripheral blood lymphocytes showed significant reduction in CD4 cells in SH-challenged birds and lower CD8α and CD8β cells in SE-challenged birds compared to controls. Our data showed that non-SE serovars have equal or higher potential to colonize reproductive tissues of laying hens and may be accompanied by altered lymphocyte populations.

  7. Genomic comparison of the closely-related Salmonella enterica serovars enteritidis, dublin and gallinarum

    DOE PAGES

    Matthews, T. David; Schmieder, Robert; Silva, Genivaldo G. Z.; ...

    2015-06-03

    The Salmonella enterica serovars Enteritidis, Dublin, and Gallinarum are closely related but differ in virulence and host range. To identify the genetic elements responsible for these differences and to better understand how these serovars are evolving, we sequenced the genomes of Enteritidis strain LK5 and Dublin strain SARB12 and compared these genomes to the publicly available Enteritidis P125109, Dublin CT 02021853 and Dublin SD3246 genome sequences. We also compared the publicly available Gallinarum genome sequences from biotype Gallinarum 287/91 and Pullorum RKS5078. Using bioinformatic approaches, we identified single nucleotide polymorphisms, insertions, deletions, and differences in prophage and pseudogene content betweenmore » strains belonging to the same serovar. Through our analysis we also identified several prophage cargo genes and pseudogenes that affect virulence and may contribute to a host-specific, systemic lifestyle. These results strongly argue that the Enteritidis, Dublin and Gallinarum serovars of Salmonella enterica evolve by acquiring new genes through horizontal gene transfer, followed by the formation of pseudogenes. The loss of genes necessary for a gastrointestinal lifestyle ultimately leads to a systemic lifestyle and niche exclusion in the host-specific serovars.« less

  8. Genotyping, pathogenicity, and immunogenicity of Avibacterium paragallinarum serovar B-1 isolates from the Americas.

    PubMed

    Morales-Erasto, V; Fernández-Rosas, P; Negrete-Abascal, E; Salazar-García, F; Blackall, P J; Soriano-Vargas, E

    2014-06-01

    The bacterium Avibacterium paragallinarum is the etiologic agent of infectious coryza of chickens. Among the nine Kume serovars currently recognized in this bacterium, serovar B-1 is a common serovar in the Americas. In the current study, serovar B-1 isolates from Ecuador (seven isolates), Mexico (seven isolates) and Panama (two isolates) were genotyped. In addition one Panamanian, one Ecuadorian, and two Mexican isolates were used in a vaccination-challenge trial in which the vaccine was based on the 2671 serovar B-1 reference strain. Genotyping by enterobacterial repetitive intergenic consensus-based PCR (ERIC-PCR) resulted in ten distinguishable ERIC patterns for the 16 isolates and the two reference strains of Av. paragallinarum included in the study. No ERIC patterns were shared among isolates of the three different countries. In the vaccination-challenge trial, one isolate from Panama showed a significantly lower virulence than did the three other isolates. In terms of cross-protection, chickens vaccinated with reference strain 2671 and challenged with an Ecuadorian strain showed 40% protection, a significantly lower protection than the homologous protection level. The other three field isolates gave a similar protection level to the homologous challenge.

  9. Chlamydial conjunctivitis: prevalence and serovar distribution of Chlamydia trachomatis in adults.

    PubMed

    Petrovay, Fruzsina; Németh, István; Balázs, Andrea; Balla, Eszter

    2015-09-01

    The extragenital manifestation of Chlamydia trachomatis infection frequently results in non-specific conjunctivitis among sexually active adults. The aims of the present study were to determine the prevalence of C. trachomatis, to describe the distribution of serovars among patients with conjunctivitis and to characterize the relationship between the prevalence and patient demographics such as age and gender. A total of 245 conjunctival specimens were screened for C. trachomatis DNA targeting the plasmid gene. Serovar determination of the C. trachomatis-positive specimens was carried out by an omp1 PCR-based RFLP analysis method. Statistical analysis was done using a generalized linear model. C. trachomatis was detected in 53 cases (21.6 %) of adult conjunctivitis. Molecular genotyping differentiated seven distinct urogenital serovars, the most prevalent being serovar E (16/53), followed by F (15/53), D (6/53), K (6/53), G (4/53), H (4/53) and J (2/53). Statistical analysis showed higher C. trachomatis prevalence in the younger age groups, and this peaked at younger age in women than in men. The high prevalence of this pathogen found in ocular samples should alert ophthalmologists to focus on the role of C. trachomatis in adult conjunctivitis. The serovar distribution indicated that ocular chlamydial infections usually have a genital source. Nevertheless, conjunctivitis might be the only sign of this sexually transmitted infection. Further comparative genotyping of C. trachomatis in ocular and genital specimens might give more detailed epidemiological information about the aetiology of the disease.

  10. Genomic Comparison of the Closely-Related Salmonella enterica Serovars Enteritidis, Dublin and Gallinarum.

    PubMed

    Matthews, T David; Schmieder, Robert; Silva, Genivaldo G Z; Busch, Julia; Cassman, Noriko; Dutilh, Bas E; Green, Dawn; Matlock, Brian; Heffernan, Brian; Olsen, Gary J; Farris Hanna, Leigh; Schifferli, Dieter M; Maloy, Stanley; Dinsdale, Elizabeth A; Edwards, Robert A

    2015-01-01

    The Salmonella enterica serovars Enteritidis, Dublin, and Gallinarum are closely related but differ in virulence and host range. To identify the genetic elements responsible for these differences and to better understand how these serovars are evolving, we sequenced the genomes of Enteritidis strain LK5 and Dublin strain SARB12 and compared these genomes to the publicly available Enteritidis P125109, Dublin CT 02021853 and Dublin SD3246 genome sequences. We also compared the publicly available Gallinarum genome sequences from biotype Gallinarum 287/91 and Pullorum RKS5078. Using bioinformatic approaches, we identified single nucleotide polymorphisms, insertions, deletions, and differences in prophage and pseudogene content between strains belonging to the same serovar. Through our analysis we also identified several prophage cargo genes and pseudogenes that affect virulence and may contribute to a host-specific, systemic lifestyle. These results strongly argue that the Enteritidis, Dublin and Gallinarum serovars of Salmonella enterica evolve by acquiring new genes through horizontal gene transfer, followed by the formation of pseudogenes. The loss of genes necessary for a gastrointestinal lifestyle ultimately leads to a systemic lifestyle and niche exclusion in the host-specific serovars.

  11. Diverse distribution of Toxin-Antitoxin II systems in Salmonella enterica serovars

    PubMed Central

    Di Cesare, Andrea; Losasso, Carmen; Barco, Lisa; Eckert, Ester M.; Conficoni, Daniele; Sarasini, Giulia; Corno, Gianluca; Ricci, Antonia

    2016-01-01

    Type II Toxin-Antitoxin systems (TAs), known for their presence in virulent and antibiotic resistant bacterial strains, were recently identified in Salmonella enterica isolates. However, the relationships between the presence of TAs (ccdAB and vapBC) and the epidemiological and genetic features of different non-typhoidal Salmonella serovars are largely unknown, reducing our understanding of the ecological success of different serovars. Salmonella enterica isolates from different sources, belonging to different serovars and epidemiologically unrelated according to ERIC profiles, were investigated for the presence of type II TAs, plasmid content, and antibiotic resistance. The results showed the ubiquitous presence of the vapBC gene in all the investigated Salmonella isolates, but a diverse distribution of ccdAB, which was detected in the most widespread Salmonella serovars, only. Analysis of the plasmid toxin ccdB translated sequence of four selected Salmonella isolates showed the presence of the amino acid substitution R99W, known to impede in vitro the lethal effect of CcdB toxin in the absence of its cognate antitoxin CcdA. These findings suggest a direct role of the TAs in promoting adaptability and persistence of the most prevalent Salmonella serovars, thus implying a wider eco-physiological role for these type II TAs. PMID:27357537

  12. Serological studies on British isolates of the Sejroe serogroup of leptospira. II. An evaluation of the factor analysis method of identifying leptospires using strains belonging to the Sejroe serogroup.

    PubMed Central

    Little, T. W.; Stevens, A. E.; Hathaway, S. C.

    1987-01-01

    Twelve British isolates of leptospira belonging to the Sejroe serogroup were examined using a series of six factor sera prepared by a number of different absorption methods. Ten of the isolates were identified as Leptospira interrogans serovar hardjo and two as L. interrogans serovar saxkoebing. These isolates had previously been identified using the cross agglutination absorption method. PMID:3609168

  13. A Leptospira borgpetersenii Serovar Hardjo vaccine induces a Th1 response, activates NK cells, and reduces renal colonization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chronic infection of cattle with Leptospira borgpetersenii serovar Hardjo reduces animal production through reproductive failure and presents a persistent health threat to workers in the animal industry. Cattle are maintenance hosts for serovar Hardjo and development of a protective vaccine has bee...

  14. Genome Sequences of Salmonella enterica subsp. enterica Serovar Infantis Strains from Hungary Representing Two Peak Incidence Periods in Three Decades

    PubMed Central

    Wilk, Tímea; Szabó, Móni; Szmolka, Ama; Kiss, János

    2017-01-01

    ABSTRACT Four strains of Salmonella enterica subsp. enterica serovar Infantis isolated from humans (1980 to 1982) and broiler chickens (2016) have been sequenced. They represent the early and recent peak incidences of this serovar in Hungary. Genome sequences of these isolates provide comparative data on the evolution and rise of an endemic S. Infantis clone in Hungary. PMID:28254986

  15. Prevalence, serovars and antimicrobial susceptibility of Salmonella spp. from wild and domestic green iguanas (Iguana iguana) in Grenada, West Indies.

    PubMed

    Sylvester, W R B; Amadi, V; Pinckney, R; Macpherson, C N L; McKibben, J S; Bruhl-Day, R; Johnson, R; Hariharan, H

    2014-09-01

    Cloacal swabs from 62 green iguanas (Iguana iguana), including 47 wild and 15 domestic ones from five parishes of Grenada, were sampled during a 4-month period of January to April 2013 and examined by enrichment and selective culture for the presence of Salmonella spp. Fifty-five per cent of the animals were positive, and eight serovars of Salmonella were isolated. The most common serovar was Rubislaw (58.8%), a serovar found recently in many cane toads in Grenada, followed by Oranienburg (14.7%), a serovar that has been causing serious human disease outbreaks in Japan. Serovar IV:48:g,z51 :- (formerly, S. Marina) highly invasive and known for serious infections in children in the United States, constituted 11.8% of the isolates, all of them being from domestic green iguanas. Salmonella Newport, a serovar recently found in a blue land crab in Grenada, comprised 11.8% of the isolates from the green iguanas. The remaining four less frequent serovars included S. Javiana and S. Glostrup. Antimicrobial susceptibility tests conducted by a disc diffusion method against amoxicillin-clavulanic acid, ampicillin, cefotaxime, ceftazidime, ciprofloxacin, enrofloxacin, gentamicin, nalidixic acid, streptomycin, tetracycline and trimethoprim-sulfamethoxazole showed that drug resistance is minimal, with intermediate susceptibility, mainly to streptomycin, tetracycline and cefotaxime. This is the first report of isolation and antimicrobial susceptibilities of various Salmonella serovars from wild and domestic green iguanas in Grenada, West Indies.

  16. Salmonella enterica serovar Kentucky isolates from dairy cows and poultry demonstrate different evolutionary histories and host-specific polymorphisms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica subsp. enterica serovar Kentucky is commonly isolated from dairy cows and poultry in the United States. Although it is not among the most frequently isolated serovars from cases of human salmonellosis, its high prevalence in livestock and poultry indicate it is a potential public...

  17. Evaluation of a multiplex PCR to identify and serotype Actinobacillus pleuropneumoniae serovars 1, 5, 7, 12 and 15.

    PubMed

    Turni, C; Singh, R; Schembri, M A; Blackall, P J

    2014-10-01

    The aim of this study was to validate a multiplex PCR for the species identification and serotyping of Actinobacillus pleuropneumoniae serovars 1, 5, 7, 12 and 15. All 15 reference strains and 411 field isolates (394 from Australia, 11 from Indonesia, five from Mexico and one from New Zealand) of A. pleuropneumoniae were tested with the multiplex PCR. The specificity of this multiplex PCR was validated on 26 non-A. pleuropneumoniae species. The multiplex PCR gave the expected results with all 15 serovar reference strains and agreed with conventional serotyping for all field isolates from serovars 1 (n = 46), 5 (n = 81), 7 (n = 80), 12 (n = 16) and serovar 15 (n = 117). In addition, a species-specific product was amplified in the multiplex PCR with all 411 A. pleuropneumoniae field isolates. Of 25 nontypeable field isolates only two did not yield a serovar-specific band in the multiplex PCR. This multiplex PCR for serovars 1, 5, 7, 12 and 15 is species specific and capable of serotyping isolates from diverse locations. Significance and impact of the study: A multiplex PCR that can recognize serovars 1, 5, 7, 12 and 15 of A. pleuropneumoniae was developed and validated. This novel diagnostic tool will enable frontline laboratories to provide key information (the serovar) to guide targeted prevention and control programmes for porcine pleuropneumonia, a serious economic disease of pigs. The previous technology, traditional serotyping, is typically provided by specialized reference laboratories, limiting the capacity to respond to this key disease.

  18. Refined live attenuated Salmonella enterica serovar Typhimurium and Enteritidis vaccines mediate homologous and heterologous serogroup protection in mice.

    PubMed

    Tennant, Sharon M; Schmidlein, Patrick; Simon, Raphael; Pasetti, Marcela F; Galen, James E; Levine, Myron M

    2015-12-01

    Invasive nontyphoidal Salmonella (NTS) infections constitute a major health problem among infants and toddlers in sub-Saharan Africa; these infections also occur in infants and the elderly in developed countries. We genetically engineered a Salmonella enterica serovar Typhimurium strain of multilocus sequence type 313, the predominant genotype circulating in sub-Saharan Africa. We evaluated the capacities of S. Typhimurium and Salmonella enterica serovar Enteritidis ΔguaBA ΔclpX live oral vaccines to protect mice against a highly lethal challenge dose of the homologous serovar and determined protection against other group B and D serovars circulating in sub-Saharan Africa. The vaccines S. Typhimurium CVD 1931 and S. Enteritidis CVD 1944 were immunogenic and protected BALB/c mice against 10,000 50% lethal doses (LD50) of S. Typhimurium or S. Enteritidis, respectively. S. Typhimurium CVD 1931 protected mice against the group B serovar Salmonella enterica serovar Stanleyville (91% vaccine efficacy), and S. Enteritidis CVD 1944 protected mice against the group D serovar Salmonella enterica serovar Dublin (85% vaccine efficacy). High rates of survival were observed when mice were infected 12 weeks postimmunization, indicating that the vaccines elicited long-lived protective immunity. Whereas CVD 1931 did not protect against S. Enteritidis R11, CVD 1944 did mediate protection against S. Typhimurium D65 (81% efficacy). These findings suggest that a bivalent (S. Typhimurium and S. Enteritidis) vaccine would provide broad protection against the majority of invasive NTS infections in sub-Saharan Africa.

  19. Refined Live Attenuated Salmonella enterica Serovar Typhimurium and Enteritidis Vaccines Mediate Homologous and Heterologous Serogroup Protection in Mice

    PubMed Central

    Schmidlein, Patrick; Simon, Raphael; Pasetti, Marcela F.; Galen, James E.; Levine, Myron M.

    2015-01-01

    Invasive nontyphoidal Salmonella (NTS) infections constitute a major health problem among infants and toddlers in sub-Saharan Africa; these infections also occur in infants and the elderly in developed countries. We genetically engineered a Salmonella enterica serovar Typhimurium strain of multilocus sequence type 313, the predominant genotype circulating in sub-Saharan Africa. We evaluated the capacities of S. Typhimurium and Salmonella enterica serovar Enteritidis ΔguaBA ΔclpX live oral vaccines to protect mice against a highly lethal challenge dose of the homologous serovar and determined protection against other group B and D serovars circulating in sub-Saharan Africa. The vaccines S. Typhimurium CVD 1931 and S. Enteritidis CVD 1944 were immunogenic and protected BALB/c mice against 10,000 50% lethal doses (LD50) of S. Typhimurium or S. Enteritidis, respectively. S. Typhimurium CVD 1931 protected mice against the group B serovar Salmonella enterica serovar Stanleyville (91% vaccine efficacy), and S. Enteritidis CVD 1944 protected mice against the group D serovar Salmonella enterica serovar Dublin (85% vaccine efficacy). High rates of survival were observed when mice were infected 12 weeks postimmunization, indicating that the vaccines elicited long-lived protective immunity. Whereas CVD 1931 did not protect against S. Enteritidis R11, CVD 1944 did mediate protection against S. Typhimurium D65 (81% efficacy). These findings suggest that a bivalent (S. Typhimurium and S. Enteritidis) vaccine would provide broad protection against the majority of invasive NTS infections in sub-Saharan Africa. PMID:26351285

  20. Draft Genome Sequence of Salmonella enterica subsp. diarizonae Serovar 61:k:1,5,(7) Strain CRJJGF_00165 (Phylum Gammaproteobacteria)

    PubMed Central

    Gupta, Sushim K.; McMillan, Elizabeth A.; Jackson, Charlene R.; Desai, Prerak T.; Porwollik, Steffen; McClelland, Michael; Hiott, Lari M.; Humayoun, Shaheen B.; Barrett, John B.

    2016-01-01

    Here, we report a 4.78-Mb draft genome sequence of the Salmonella enterica subsp. diarizonae serovar 61:k:1,5,(7) strain CRJJGF_00165 [also called S. enterica subsp. IIIb serovar 61:k:1,5,(7) strain CRJJGF_00165], isolated from ground beef in 2007. PMID:27881547

  1. Genome Sequences of Salmonella enterica subsp. enterica Serovar Infantis Strains from Hungary Representing Two Peak Incidence Periods in Three Decades.

    PubMed

    Wilk, Tímea; Szabó, Móni; Szmolka, Ama; Kiss, János; Olasz, Ferenc; Nagy, Béla

    2017-03-02

    Four strains of Salmonella enterica subsp. enterica serovar Infantis isolated from humans (1980 to 1982) and broiler chickens (2016) have been sequenced. They represent the early and recent peak incidences of this serovar in Hungary. Genome sequences of these isolates provide comparative data on the evolution and rise of an endemic S Infantis clone in Hungary.

  2. Rapid determination of lymphogranuloma venereum serovars of Chlamydia trachomatis by quantitative high-resolution melt analysis (HRMA).

    PubMed

    Twin, Jimmy; Stevens, Matthew P; Garland, Suzanne M; Zaia, Angelo M; Tabrizi, Sepehr N

    2012-11-01

    A quantitative high-resolution melt analysis assay was developed to differentiate lymphogranuloma venereum-causing serovars of Chlamydia trachomatis (L1 to L3) from other C. trachomatis serovars (D to K). The detection limit of this assay is approximately 10 copies per reaction, comparable to the limits of other quantitative-PCR-based methods.

  3. Validating GEOV3 LAI, FAPAR and vegetation cover estimates derived from PROBA-V observations at 333m over Europe

    NASA Astrophysics Data System (ADS)

    Camacho, Fernando; Sánchez, Jorge; Lacaze, Roselyne; Weiss, Marie; Baret, Frédéric; Verger, Aleixandre; Smets, Bruno; Latorre, Consuelo

    2016-04-01

    The Copernicus Global Land Service (http://land.copernicus.eu/global/) is delivering surface biophysical products derived from satellite observations at global scale. Fifteen years of LAI, FAPAR, and vegetation cover (FCOVER) products among other indicators have been generated from SPOT/VGT observations at 1 km spatial resolution (named GEOV1, GEOV2). The continuity of the service since the end of SPOT/VGT mission (May, 2014) is achieved thanks to PROBA-V, which offers observations at a finer spatial resolution (1/3 km). In the context of the FP7 ImagineS project (http://fp7-imagines.eu/), a new algorithm (Weiss et al., this conference), adapted to PROBA-V spectral and spatial characteristics, was designed to provide vegetation products (named GEOV3) as consistent as possible with GEOV1 and GEOV2 whilst providing near real-time estimates required by some users. It is based on neural network techniques completed with a data filtering and smoothing process. The near real-time estimates are improved through a consolidation period of six dekads during which observations are accumulated every new dekad. The validation of these products is mandatory to provide associated uncertainties for efficient use of this source of information. This work presents an early validation over Europe of the GEOV3 LAI, FAPAR and vegetation cover (FCOVER) products derived from PROBA-V observation at 333 m and 10-days frequency during the year 2014. The validation has been conducted in agreement with the CEOS LPV best practices for global LAI products. Several performance criteria were investigated for the several GEOV3 modes (near real-time, and successive consolidated estimates) including completeness, spatial and temporal consistency, precision and accuracy. The spatial and temporal consistency was evaluated using as reference PROBA-V GEOV1 and MODC5 1 km similar products using a network of 153 validation sites over Europe (EUVAL). The accuracy was assessed with concomitant data collected

  4. Vertical Chlorophyll Canopy Structure Affects the Remote Sensing Based Predictability of LAI, Chlorophyll and Leaf Nitrogen in Agricultural Fields

    NASA Astrophysics Data System (ADS)

    Boegh, E.; Houborg, R.; Bienkowski, J.; Braban, C. F.; Dalgaard, T.; van Dijk, N.; Dragosits, U.; Holmes, E.; Magliulo, V.; Schelde, K.; Di Tommasi, P.; Vitale, L.; Theobald, M.; Cellier, P.; Sutton, M.

    2012-12-01

    Leaf nitrogen and leaf surface area influence the exchange of gases between terrestrial ecosystems and the atmosphere, and they play a significant role in the global cycles of carbon, nitrogen and water. Remote sensing can be used to estimate leaf area index (LAI), chlorophyll content (CHL) and leaf nitrogen (N), but methods are often developed using plot-scale data and not verified over extended regions characterized by variations in environmental boundary conditions (soil, atmosphere) and canopy structures. Estimation of N can be indirect due to its association with CHL, however N is also included in pigments such as carotenoids and anthocyanin which have different spectral signatures than CHL. Photosynthesis optimization theory suggests that plants will distribute their N resources in proportion to the light gradient within the canopy. Such vertical variation in CHL and N complicates the evaluation of remote sensing-based methods. Typically remote sensing studies measure CHL of the upper leaf, which is then multiplied by the green LAI to represent canopy chlorophyll content, or random sampling is used. In this study, field measurements and high spatial resolution (10-20 m) remote sensing images acquired from the HRG and HRVIR sensors aboard the SPOT satellites were used to assess the predictability of LAI, CHL and N in five European agricultural landscapes located in Denmark, Scotland (United Kingdom), Poland, The Netherlands and Italy . All satellite images were atmospherically using the 6SV1 model with atmospheric inputs estimated by MODIS and AIRS data. Five spectral vegetation indices (SVIs) were calculated (the Normalized Difference Vegetation index, the Simple Ratio, the Enhanced Vegetation Index-2, the Green Normalized Difference Vegetation Index, and the green Chlorophyll Index), and an image-based inverse canopy radiative transfer modelling system, REGFLEC (REGularized canopy reFLECtance) was applied to each of the five European landscapes. While the

  5. The new pLAI (lux regulon based auto-inducible) expression system for recombinant protein production in Escherichia coli

    PubMed Central

    2012-01-01

    Background After many years of intensive research, it is generally assumed that no universal expression system can exist for high-level production of a given recombinant protein. Among the different expression systems, the inducible systems are the most popular for their tight regulation. However, induction is in many cases less favorable due to the high cost and/or toxicity of inducers, incompatibilities with industrial scale-up or detrimental growth conditions. Expression systems using autoinduction (or self-induction) prove to be extremely versatile allowing growth and induction of recombinant proteins without the need to monitor cell density or add inducer. Unfortunately, almost all the actual auto inducible expression systems need endogenous or induced metabolic changes during the growth to trigger induction, both frequently linked to detrimental condition to cell growth. In this context, we use a simple modular approach for a cell density-based genetic regulation in order to assemble an autoinducible recombinant protein expression system in E. coli. Result The newly designed pLAI expression system places the expression of recombinant proteins in Escherichia coli under control of the regulatory genes of the lux regulon of Vibrio fischeri's Quorum Sensing (QS) system. The pLAI system allows a tight regulation of the recombinant gene allowing a negligible basal expression and expression only at high cell density. Sequence optimization of regulative genes of QS of V. fischeri for expression in E. coli upgraded the system to high level expression. Moreover, partition of regulative genes between the plasmid and the host genome and introduction of a molecular safety lock permitted tighter control of gene expression. Conclusion Coupling gene expression to cell density using cell-to-cell communication provides a promising approach for recombinant protein production. The system allows the control of expression of the target recombinant gene independently from external

  6. Transforming Pinus pinaster forest to recreation site: preliminary effects on LAI, some forest floor, and soil properties.

    PubMed

    Öztürk, Melih; Bolat, İlyas

    2014-04-01

    This study investigates the effects of forest transformation into recreation site. A fragment of a Pinus pinaster plantation forest was transferred to a recreation site in the city of Bartın located close to the Black Sea coast of northwestern Turkey. During the transformation, some of the trees were selectively removed from the forest to generate more open spaces for the recreationists. As a result, Leaf Area Index (LAI) decreased by 0.20 (about 11%). Additionally, roads and pathways were introduced into the site together with some recreational equipment sealing parts of the soil surface. Consequently, forest environment was altered with a semi-natural landscape within the recreation site. The purpose of this study is to assess the effects of forest transformation into recreation site particularly in terms of the LAI parameter, forest floor, and soil properties. Preliminary monitoring results indicate that forest floor biomass is reduced by 26% in the recreation site compared to the control site. Soil temperature is increased by 15% in the recreation site where selective removal of trees expanded the gaps allowing more light transmission. On the other hand, the soil bulk density which is an indicator of soil compaction is unexpectedly slightly lower in the recreation site. Organic carbon (C(org)) and total nitrogen (N(total)) together with the other physical and chemical parameter values indicate that forest floor and soil have not been exposed to much disturbance. However, subsequent removal of trees that would threaten the vegetation, forest floor, and soil should not be allowed. The activities of the recreationists are to be concentrated on the paved spaces rather than soil surfaces. Furthermore, long-term monitoring and management is necessary for both the observation and conservation of the site.

  7. Ocular sensitization of mice by live (but not irradiated) Chlamydia trachomatis serovar A

    SciTech Connect

    Colley, D.G.; Goodman, T.G.; Barsoum, I.S.

    1986-10-01

    Ocular exposure of mice to live elementary bodies of Chlamydia trachomatis serovar A results in immunological sensitization of the mice. This reactivity is manifested by the development of early (5 h) and delayed-type (24 h) dermal reactivity and serovar-specific antibody formation against either live or irradiated (100 kilorads) elementary bodies. Parallel ocular exposure of mice to irradiated elementary bodies does not result in this sensitization. The early and late dermal immune responses induced by ocular exposure to live organisms can be transferred to unexposed mice by serum and lymphoid cell transfers, respectively. It appears that successful murine ocular sensitization by human C. trachomatis serovar A elementary bodies is an ability manifested by live organisms and not by inactivated but antigenic organisms.

  8. Repeated isolation of Salmonella enterica Goverdhan, a very rare serovar, from Danish poultry surveillance samples.

    PubMed

    Pedersen, Karl; Sørensen, Gitte; Szabo, Istvan; Hächler, Herbert; Le Hello, Simon

    2014-12-05

    We report here the appearance of a very rare serovar of Salmonella, S. enterica subsp. enterica serovar Goverdhan, in routine Salmonella surveillance samples from Danish poultry production. S. Goverdhan was found on nine occasions: in one broiler breeder farm in October 2010, four broiler farms and one broiler breeder farm in June-September 2012, two broiler breeder flocks simultaneously in June 2013, and one layer flock in July 2013. The five isolates from 2012 and the three isolates from 2013 had identical pulsed-field gel electrophoresis profiles, whereas the profile of the isolate from 2010 deviated in a single band. It is the first time this serovar has been described in samples from poultry. The origin of the bacterium is still unknown, but it is suggested that it may have been a pseudo-outbreak caused by contaminated sampling material.

  9. Comparative genomic analysis of Brazilian Leptospira kirschneri serogroup Pomona serovar Mozdok

    PubMed Central

    Moreno, Luisa Z; Kremer, Frederico S; Miraglia, Fabiana; Loureiro, Ana P; Eslabao, Marcus R; Dellagostin, Odir A; Lilenbaum, Walter; Moreno, Andrea M

    2016-01-01

    Leptospira kirschneri is one of the pathogenic species of the Leptospira genus. Human and animal infection from L. kirschneri gained further attention over the last few decades. Here we present the isolation and characterisation of Brazilian L. kirschneri serogroup Pomona serovar Mozdok strain M36/05 and the comparative genomic analysis with Brazilian human strain 61H. The M36/05 strain caused pulmonary hemorrhagic lesions in the hamster model, showing high virulence. The studied genomes presented high symmetrical identity and the in silico multilocus sequence typing analysis resulted in a new allelic profile (ST101) that so far has only been associated with the Brazilian L. kirschneri serogroup Pomona serovar Mozdok strains. Considering the environmental conditions and high genomic similarity observed between strains, we suggest the existence of a Brazilian L. kirschneri serogroup Pomona serovar Mozdok lineage that could represent a high public health risk; further studies are necessary to confirm the lineage significance and distribution. PMID:27581124

  10. Cross-protection study of the nine serovars of Haemophilus paragallinarum in the Kume haemagglutinin scheme.

    PubMed

    Soriano, Edgardo V; Garduño, Manuel Longinos; Téllez, Guillermo; Rosas, Pomposo Fernández; Suárez-Güemes, Francisco; Blackall, Patrick J

    2004-10-01

    The cross-protection and haemagglutination-inhibition antibodies present in chickens vaccinated with one of the nine currently recognized Kume haemagglutinin serovars of Haemophilus paragallinarum were investigated. The results confirmed the widely accepted dogma that serogroups A, B, and C represent three distinct immunovars. Within Kume serogroup A, there was generally good cross-protection among all four serovars. However, within Kume serogroup C, there was evidence of a reduced level of cross-protection between some of the four serovars. The haemagglutination-inhibition antibody levels generally showed the same trend as with the cross-protection results. This study suggests that some apparent field failures of infectious coryza vaccines may be due to a lack of cross-protection between the vaccine strains and the field strains. Our results will help guide the selection of strains for inclusion in infectious coryza vaccines.

  11. Prevalence of antibodies to Leptospira serovars in sheep and goats in Alto Adige-South Tyrol.

    PubMed

    Ciceroni, L; Lombardo, D; Pinto, A; Ciarrocchi, S; Simeoni, J

    2000-04-01

    Serum samples from 313 sheep and 95 goats were collected during November 1993 in 26 localities in Alto Adige-South Tyrol and tested by microscopic agglutination test for antibodies to 28 serovars of the genus Leptospira. At the time of blood collection all the animals appeared healthy with no clinical sign suggestive of leptospirosis. The observed seroprevalence in sheep was 6.1%, whereas the seropositivity rate for goat serum samples was 2.1%. The highest serological prevalence in sheep was recorded for serovar castellonis, followed by poi, sejroe, hardjo subtype hardjobovis, copenhageni, and cynopteri. Titres to poi were the only ones found in goats. These findings, which are proof of Leptospira infection in Alto Adige-South Tyrol, indicate that foci of several serovars exist in this region.

  12. Same species, different diseases: how and why typhoidal and non-typhoidal Salmonella enterica serovars differ

    PubMed Central

    Gal-Mor, Ohad; Boyle, Erin C.; Grassl, Guntram A.

    2014-01-01

    Human infections by the bacterial pathogen Salmonella enterica represent major disease burdens worldwide. This highly ubiquitous species consists of more than 2600 different serovars that can be divided into typhoidal and non-typhoidal Salmonella (NTS) serovars. Despite their genetic similarity, these two groups elicit very different diseases and distinct immune responses in humans. Comparative analyses of the genomes of multiple Salmonella serovars have begun to explain the basis of the variation in disease manifestations. Recent advances in modeling both enteric fever and intestinal gastroenteritis in mice will facilitate investigation into both the bacterial- and host-mediated mechanisms involved in salmonelloses. Understanding the genetic and molecular mechanisms responsible for differences in disease outcome will augment our understanding of Salmonella pathogenesis, host immunity, and the molecular basis of host specificity. This review outlines the differences in epidemiology, clinical manifestations, and the human immune response to typhoidal and NTS infections and summarizes the current thinking on why these differences might exist. PMID:25136336

  13. Comparative genomic analysis of Brazilian Leptospira kirschneri serogroup Pomona serovar Mozdok.

    PubMed

    Moreno, Luisa Z; Kremer, Frederico S; Miraglia, Fabiana; Loureiro, Ana P; Eslabao, Marcus R; Dellagostin, Odir A; Lilenbaum, Walter; Moreno, Andrea M

    2016-08-01

    Leptospira kirschneri is one of the pathogenic species of the Leptospira genus. Human and animal infection from L. kirschneri gained further attention over the last few decades. Here we present the isolation and characterisation of Brazilian L. kirschneri serogroup Pomona serovar Mozdok strain M36/05 and the comparative genomic analysis with Brazilian human strain 61H. The M36/05 strain caused pulmonary hemorrhagic lesions in the hamster model, showing high virulence. The studied genomes presented high symmetrical identity and the in silico multilocus sequence typing analysis resulted in a new allelic profile (ST101) that so far has only been associated with the Brazilian L. kirschneri serogroup Pomona serovar Mozdok strains. Considering the environmental conditions and high genomic similarity observed between strains, we suggest the existence of a Brazilian L. kirschneri serogroup Pomona serovar Mozdok lineage that could represent a high public health risk; further studies are necessary to confirm the lineage significance and distribution.

  14. Utility of an image-based canopy reflectance modeling tool for remote estimation of LAI and leaf chlorophyll content at the field scale

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A REGularized canopy reFLECtance (REGFLEC) modeling tool that couples leaf optics (PROSPECT), canopy reflectance (ACRM), and atmospheric radiative transfer (6SV1) models is described and the model output of leaf chlorophyll (Cab) and total leaf area index (LAI) is validated against ground measuremen...

  15. Statistical derivation of fPAR and LAI for irrigated cotton and rice in arid Uzbekistan by combining multi-temporal RapidEye data and ground measurements

    NASA Astrophysics Data System (ADS)

    Ehammer, Andrea; Fritsch, Sebastian; Conrad, Christopher; Lamers, John; Dech, Stefan

    2010-10-01

    Land surface biophysical parameters such as the fraction of photosynthetic active radiation (fPAR) and leaf area index (LAI) are keys for monitoring vegetation dynamics and in particular for biomass and carbon flux simulation. This study aimed at deriving accurate regression equations from the newly available RapidEye satellite sensor to be able to map regional fPAR and LAI which could be used as inputs for crop growth simulations. Therefore, multi-temporal geo- and atmospherically corrected RapidEye scenes were segmented to derive homogeneous patches within the experimental fields. Various vegetation indices (VI) were calculated for each patch focusing on indices that include RapidEye's red edge band and further correlated with in situ measured fPAR and LAI values of cotton and rice. Resulting coefficients of determination ranged from 0.55 to 0.95 depending on the indices analysed, object scale, crop type and regression function type. The general relationships between VI and fPAR were found to be linear. Nonlinear models gave a better fit for VI-LAI relation. VIs derived from the red edge channel did not prove to be generally superior to other VIs.

  16. Comparison of satellite-derived LAI and precipitation anomalies over Brazil with a thermal infrared-based Evaporative Stress Index for 2003-2013

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shortwave vegetation index (VI) and leaf area index (LAI) remote sensing products yield inconsistent depictions of biophysical response to drought and pluvial events that have occurred in Brazil over the past decade. Conflicting reports of severity of drought impacts on vegetation health and funct...

  17. LAI (in situ, simulated, Landsat-derived, and MODIS): A comparison within an Oak-Hickory Forest Complex in southwestern Virginia, USA.

    EPA Science Inventory

    The United States Environmental Protection Agency’s Environmental Sciences and Atmospheric Modeling Analysis Divisions are investigating the viability of simulated (i.e., ‘modeled’) leaf area index (LAI) inputs into various regional and local scale air quality models. Satellite L...

  18. Diversity and antimicrobial susceptibility of Salmonella enterica serovars isolated from pig farms in Ibadan, Nigeria.

    PubMed

    Fashae, Kayode; Hendriksen, Rene S

    2014-01-01

    Animals including food animals play a significant role in the epidemiology of Salmonella enterica. The control requires identification of sources and institution of targeted interventions. This study investigates the diversity of S. enterica serovars, antimicrobial susceptibility, and occurrence of plasmid-mediated quinolone resistance (PMQR) genes in pigs in Ibadan, Nigeria. Pooled fresh pen floor fecal samples of pigs collected from 31 pig farms were cultured; the Salmonella isolates were serotyped and their antimicrobial susceptibility was determined. PMQR genes were screened by polymerase chain reaction. The 229 Salmonella isolates were made of 50 serovars predominated by rare serovars Salmonella Give (n = 36; 15.7 %), Salmonella Brancaster (n = 17; 7.4 %), Salmonella Colindale (n = 15; 6.6 %), Salmonella Elisaberthville (n = 13; 5.7 %), Salmonella Hillingdon (n = 13; 5.7 %), and Salmonella Kingston (n = 13; 5.7 %). The most widely distributed serovars among the farms were Salmonella Give (six farms) and Salmonella Elisaberthville (six farms). Resistance to chloramphenicol, sulfonamides, nalidixic acid, streptomycin, and tetracycline ranged from 11.6 % (n = 26) to 22.8 % (n = 51). Resistance ciprofloxacin and gentamicin was low (n = 2; 0.9 %). Multiply resistant isolates included Salmonella Kentucky, the most resistant serovar. qnrB19 was found in two isolates of Salmonella Corvallis and one isolate of Salmonella Larochelle, respectively, while qnrS1 was found in two isolates of Salmonella Derby. Other PMQR genes were not detected. Pigs constitute an important source of diverse Salmonella serovars in Ibadan. The isolates were more resistant to old antimicrobials with some multiple resistant. Control measures and regulation of antimicrobials are warranted.

  19. Antibiotic resistance profiles of Salmonella serovars isolated from retail pork and chicken meat in North Vietnam.

    PubMed

    Thai, Truong Ha; Hirai, Takuya; Lan, Nguyen Thi; Yamaguchi, Ryoji

    2012-05-15

    The spread of antibiotic resistance via meat poses a serious public health concerns. During 2007-2009, a total of 586 retail meat samples (318 pork and 268 chicken meats) were collected from three provinces (Bac Ninh, Ha Noi and Ha Tay) of North Vietnam to determine the prevalence of Salmonella. Isolates were characterized by serotyping and antibiotic susceptibility testing. Approximately 39.6% (n=126) of pork and 42.9% (n=115) of chicken samples were Salmonella-positive, and 14 Salmonella serovars were identified. Anatum (15.8%) was the most common serovar, followed by Infantis (13.3%), Emek (10.4%), Derby and Rissen (9.5%), Typhimurium (9.1%), Reading (7.5%) and London (6.2%). The isolation frequency of serovars Enteritidis, Albany, Hadar, Weltevreden, Newport and Blockey ranged from 1.2%-5.8%. Resistance to at least one antibiotic agent was detected in 78.4% of isolates (n=189) and the most frequent resistance were to tetracycline (58.5%), sulphonamides (58.1%), streptomycin (47.3%), ampicillin (39.8%), chloramphenicol (37.3%), trimethoprim (34.0%) and nalidixic acid (27.8%). No Salmonella isolates were resistant to ceftazidime. Chicken isolates had higher resistance to antibiotic agents than pork isolates (P<0.05). It showed that 159 Salmonella isolates belong to the 14 serovars were multidrug resistant (MDR) and 50 MDR patterns were found. This study indicated that Salmonella serovars isolated from retail meat samples were resistant to multiple antibiotics and this resistance was widespread among different serovars. The widespread resistance may have arisen from misuse or overuse of antibiotics during animal husbandry in North Vietnam.

  20. Detection of Vibrio cholerae with monoclonal antibodies specific for serovar O1 lipopolysaccharide.

    PubMed Central

    Adams, L B; Henk, M C; Siebeling, R J

    1988-01-01

    Six hybridoma cell lines, each of which produced a monoclonal antibody (MAb) against Vibrio cholerae O1 lipopolysaccharide (LPS), were established. Each MAb was active serologically by both enzyme-linked immunosorbent assay (ELISA) and the slide agglutination test. In the ELISA, each MAb was tested against 7 O1 and 9 non-O1 LPS preparations. Three MAbs reacted with both Inaba and Ogawa serovars (A antigen), two MAbs reacted with the Ogawa serovars only (B antigen), and one MAb reacted with the Inaba serovars only (C antigen). Each MAb was also tested in the ELISA against whole-cell preparations of 37 O1 and 52 non-O1 V. cholerae serovars, 20 heterologous Vibrio species, and 37 heterologous bacterial species. The MAbs reacted with V. cholerae O1 cells only, except for one anti-A antigen MAb which reacted weakly with five V. cholerae non-O1 serovars and Serratia marcescens. Each anti-A antigen MAb was labeled with fluorescein isothiocyanate (FITC) and tested by direct immunofluorescence against selected O1 and non-O1 serovars. Each MAb-FITC conjugate, when tested alone, exhibited O1-specific fluorescence; however, mixtures of the MAb-FITC dramatically enhanced fluorescence intensity on O1 cells. This finding was also visualized by immunoelectron microscopy on both thin-sectioned and negatively stained O1 cells by using an anti-mouse immunoglobulin-colloidal gold conjugate. These results suggest that the A antigen can be described by more than one epitope and that a superior serotyping reagent can be prepared from a defined mixture of MAbs. Images PMID:3053778

  1. Low-stringency PCR with diagnostically useful primers for identification of Leptospira serovars.

    PubMed Central

    de Caballero, O L; Dias Neto, E; Koury, M C; Romanha, A J; Simpson, A J

    1994-01-01

    Primers proposed for the diagnosis of the pathogenic spirochete Leptospira spp. (C. Gravekamp, H. V. D. Kemp, M. Franzen, D. Carrington, G.J. Schoone, G.J.J.M. Van Eys, C. O. R. Everard, R.A. Hartskeel, and W.J. Terpstra, J. Gen. Microbiol. 139:1691-1700, 1993) have been found to produce complex serovar-specific patterns under low-stringency PCR conditions. Such patterns obtained by low-stringency PCR, which maintain the specific band as an internal control, offer, an approach to the standardized identification of Leptospira serovars in clinical laboratories. Images PMID:8051272

  2. Global Genomic Epidemiology of Salmonella enterica Serovar Typhimurium DT104

    DOE PAGES

    Leekitcharoenphon, Pimlapas; Hendriksen, Rene S.; Le Hello, Simon; ...

    2016-03-04

    It has been 30 years since the initial emergence and subsequent rapid global spread of multidrug-resistant Salmonella enterica serovar Typhimurium DT104 (MDR DT104). Nonetheless, its origin and transmission route have never been revealed. In this paper, we used whole-genome sequencing (WGS) and temporally structured sequence analysis within a Bayesian framework to reconstruct temporal and spatial phylogenetic trees and estimate the rates of mutation and divergence times of 315 S. Typhimurium DT104 isolates sampled from 1969 to 2012 from 21 countries on six continents. DT104 was estimated to have emerged initially as antimicrobial susceptible in ~1948 (95% credible interval [CI], 1934more » to 1962) and later became MDR DT104 in ~1972 (95% CI, 1972 to 1988) through horizontal transfer of the 13-kb Salmonella genomic island 1 (SGI1) MDR region into susceptible strains already containing SGI1. This was followed by multiple transmission events, initially from central Europe and later between several European countries. An independent transmission to the United States and another to Japan occurred, and from there MDR DT104 was probably transmitted to Taiwan and Canada. An independent acquisition of resistance genes took place in Thailand in ~1975 (95% CI, 1975 to 1990). In Denmark, WGS analysis provided evidence for transmission of the organism between herds of animals. Interestingly, the demographic history of Danish MDR DT104 provided evidence for the success of the program to eradicate Salmonella from pig herds in Denmark from 1996 to 2000. Finally, the results from this study refute several hypotheses on the evolution of DT104 and suggest that WGS may be useful in monitoring emerging clones and devising strategies for prevention of Salmonella infections.« less

  3. Global Genomic Epidemiology of Salmonella enterica Serovar Typhimurium DT104

    SciTech Connect

    Leekitcharoenphon, Pimlapas; Hendriksen, Rene S.; Le Hello, Simon; Weill, François-Xavier; Baggesen, Dorte Lau; Jun, Se-Ran; Ussery, David W.; Lund, Ole; Crook, Derrick W.; Wilson, Daniel J.; Aarestrup, Frank M.

    2016-03-04

    It has been 30 years since the initial emergence and subsequent rapid global spread of multidrug-resistant Salmonella enterica serovar Typhimurium DT104 (MDR DT104). Nonetheless, its origin and transmission route have never been revealed. In this paper, we used whole-genome sequencing (WGS) and temporally structured sequence analysis within a Bayesian framework to reconstruct temporal and spatial phylogenetic trees and estimate the rates of mutation and divergence times of 315 S. Typhimurium DT104 isolates sampled from 1969 to 2012 from 21 countries on six continents. DT104 was estimated to have emerged initially as antimicrobial susceptible in ~1948 (95% credible interval [CI], 1934 to 1962) and later became MDR DT104 in ~1972 (95% CI, 1972 to 1988) through horizontal transfer of the 13-kb Salmonella genomic island 1 (SGI1) MDR region into susceptible strains already containing SGI1. This was followed by multiple transmission events, initially from central Europe and later between several European countries. An independent transmission to the United States and another to Japan occurred, and from there MDR DT104 was probably transmitted to Taiwan and Canada. An independent acquisition of resistance genes took place in Thailand in ~1975 (95% CI, 1975 to 1990). In Denmark, WGS analysis provided evidence for transmission of the organism between herds of animals. Interestingly, the demographic history of Danish MDR DT104 provided evidence for the success of the program to eradicate Salmonella from pig herds in Denmark from 1996 to 2000. Finally, the results from this study refute several hypotheses on the evolution of DT104 and suggest that WGS may be useful in monitoring emerging clones and devising strategies for prevention of Salmonella infections.

  4. Acid exposure induces multiplication of Salmonella enterica serovar Typhi.

    PubMed

    Ahirwar, Suneel Kumar; Pratap, Chandra Bhan; Patel, Saurabh Kumar; Shukla, Vijay K; Singh, Indarjeet Gambhir; Mishra, Om Prakash; Kumar, Kailash; Singh, Tej Bali; Nath, Gopal

    2014-12-01

    Salmonella enterica serovar Typhi faces several environmental stresses while going through the stomach (acidic pH) to the small intestine (basic pH) and intracellularly in macrophages (acidic pH) in humans. The acidic pH followed by alkaline pH in the small intestine might be responsible for expression of certain stress-induced genes, resulting in not only better survival but also induction of multiplication and invasion of the bacterium in the small intestine. Based on this hypothesis, we developed a process wherein we exposed the blood, urine, and stool specimens from 90 acute typhoid fever patients and 36 chronic typhoid carriers to acidic pH to see the effect on isolation rate of S. Typhi. About 5 g of freshly passed unpreserved stool, a centrifuged deposit of 15 ml of urine, and 5 ml of blood clot were subjected to 5 ml of Luria-Bertani (LB) broth (pH 3.5) for 20 min, followed by enrichment in bile broth-selenite F broth. When the combined isolation from all 3 specimens, i.e., blood, urine, and stool, after acid exposure was considered, a total of 77.7% of the acute typhoid patients were observed to be positive for the isolation of the S. Typhi serotype, compared to 8.8% by the conventional method. Similarly, 42% (15/36) of chronic carriers yielded positive for S. Typhi growth after acid exposure, compared to 5.5% (2/36) by the conventional method. It therefore can be concluded that acid shock triggers the multiplication of the bacteria, resulting in better isolation rates from blood clot, stool, and urine specimens.

  5. Polyamines Are Required for Virulence in Salmonella enterica Serovar Typhimurium

    PubMed Central

    Jelsbak, Lotte; Thomsen, Line Elnif; Wallrodt, Inke; Jensen, Peter Ruhdal; Olsen, John Elmerdahl

    2012-01-01

    Sensing and responding to environmental cues is a fundamental characteristic of bacterial physiology and virulence. Here we identify polyamines as novel environmental signals essential for virulence of Salmonella enterica serovar Typhimurium, a major intracellular pathogen and a model organism for studying typhoid fever. Central to its virulence are two major virulence loci Salmonella Pathogenicity Island 1 and 2 (SPI1 and SPI2). SPI1 promotes invasion of epithelial cells, whereas SPI2 enables S. Typhimurium to survive and proliferate within specialized compartments inside host cells. In this study, we show that an S. Typhimurium polyamine mutant is defective for invasion, intracellular survival, killing of the nematode Caenorhabditis elegans and systemic infection of the mouse model of typhoid fever. Virulence of the mutant could be restored by genetic complementation, and invasion and intracellular survival could, as well, be complemented by the addition of exogenous putrescine and spermidine to the bacterial cultures prior to infection. Interestingly, intracellular survival of the polyamine mutant was significantly enhanced above the wild type level by the addition of exogenous putrescine and spermidine to the bacterial cultures prior to infection, indicating that these polyamines function as an environmental signal that primes S. Typhimurium for intracellular survival. Accordingly, experiments addressed at elucidating the roles of these polyamines in infection revealed that expression of genes from both of the major virulence loci SPI1 and SPI2 responded to exogenous polyamines and was reduced in the polyamine mutant. Together our data demonstrate that putrescine and spermidine play a critical role in controlling virulence in S. Typhimurium most likely through stimulation of expression of essential virulence loci. Moreover, our data implicate these polyamines as key signals in S. Typhimurium virulence. PMID:22558361

  6. Characterization of Salmonella enterica serovar Typhimurium aconitase A.

    PubMed

    Baothman, Othman A S; Rolfe, Matthew D; Green, Jeffrey

    2013-06-01

    Aconitases (Acn) are iron-sulfur proteins that catalyse the reversible isomerization of citrate and isocitrate via the intermediate cis-aconitate in the Krebs cycle. Some Acn proteins are bi-functional and under conditions of iron starvation and oxidative stress lose their iron-sulfur clusters and become post-transcriptional regulators by binding specific mRNA targets. Many bacterial species possess two genetically distinct aconitase proteins, AcnA and AcnB. Current understanding of the regulation and functions of AcnA and AcnB in dual Acn bacteria is based on a model developed in Escherichia coli. Thus, AcnB is the major Krebs cycle enzyme expressed during exponential growth, whereas AcnA is a more stable, stationary phase and stress-induced enzyme, and both E. coli Acns are bi-functional. Here a second dual Acn bacterium, Salmonella enterica serovar Typhimurium (S. Typhimurium), has been analysed. Phenotypic traits of S. Typhimurium acn mutants were consistent with AcnB acting as the major Acn protein. Promoter fusion experiments indicated that acnB transcription was ~10-fold greater than that of acnA and that acnA expression was regulated by the cyclic-AMP receptor protein (CRP, glucose starvation), the fumarate nitrate reduction regulator (FNR, oxygen starvation), the ferric uptake regulator (Fur, iron starvation) and the superoxide response protein (SoxR, oxidative stress). In contrast to E. coli, S. Typhimurium acnA was not induced in the stationary phase. Furthermore, acnA expression was enhanced in an acnB mutant, presumably to partially compensate for the lack of AcnB activity. Isolated S. Typhimurium AcnA protein had kinetic and mRNA-binding properties similar to those described for E. coli AcnA. Thus, the work reported here provides a second example of the regulation and function of AcnA and AcnB proteins in a dual Acn bacterium.

  7. Global Genomic Epidemiology of Salmonella enterica Serovar Typhimurium DT104

    PubMed Central

    Hendriksen, Rene S.; Le Hello, Simon; Weill, François-Xavier; Baggesen, Dorte Lau; Jun, Se-Ran; Lund, Ole; Crook, Derrick W.; Wilson, Daniel J.; Aarestrup, Frank M.

    2016-01-01

    It has been 30 years since the initial emergence and subsequent rapid global spread of multidrug-resistant Salmonella enterica serovar Typhimurium DT104 (MDR DT104). Nonetheless, its origin and transmission route have never been revealed. We used whole-genome sequencing (WGS) and temporally structured sequence analysis within a Bayesian framework to reconstruct temporal and spatial phylogenetic trees and estimate the rates of mutation and divergence times of 315 S. Typhimurium DT104 isolates sampled from 1969 to 2012 from 21 countries on six continents. DT104 was estimated to have emerged initially as antimicrobial susceptible in ∼1948 (95% credible interval [CI], 1934 to 1962) and later became MDR DT104 in ∼1972 (95% CI, 1972 to 1988) through horizontal transfer of the 13-kb Salmonella genomic island 1 (SGI1) MDR region into susceptible strains already containing SGI1. This was followed by multiple transmission events, initially from central Europe and later between several European countries. An independent transmission to the United States and another to Japan occurred, and from there MDR DT104 was probably transmitted to Taiwan and Canada. An independent acquisition of resistance genes took place in Thailand in ∼1975 (95% CI, 1975 to 1990). In Denmark, WGS analysis provided evidence for transmission of the organism between herds of animals. Interestingly, the demographic history of Danish MDR DT104 provided evidence for the success of the program to eradicate Salmonella from pig herds in Denmark from 1996 to 2000. The results from this study refute several hypotheses on the evolution of DT104 and suggest that WGS may be useful in monitoring emerging clones and devising strategies for prevention of Salmonella infections. PMID:26944846

  8. Variable Carbon Catabolism among Salmonella enterica Serovar Typhi Isolates

    PubMed Central

    Chai, Lay Ching; Kong, Boon Hong; Elemfareji, Omar Ismail; Thong, Kwai Lin

    2012-01-01

    Background Salmonella enterica serovar Typhi (S. Typhi) is strictly a human intracellular pathogen. It causes acute systemic (typhoid fever) and chronic infections that result in long-term asymptomatic human carriage. S. Typhi displays diverse disease manifestations in human infection and exhibits high clonality. The principal factors underlying the unique lifestyle of S. Typhi in its human host during acute and chronic infections remain largely unknown and are therefore the main objective of this study. Methodology/Principal Findings To obtain insight into the intracellular lifestyle of S. Typhi, a high-throughput phenotypic microarray was employed to characterise the catabolic capacity of 190 carbon sources in S. Typhi strains. The success of this study lies in the carefully selected library of S. Typhi strains, including strains from two geographically distinct areas oftyphoid endemicity, an asymptomatic human carrier, clinical stools and blood samples and sewage-contaminated rivers. An extremely low carbon catabolic capacity (27% of 190 carbon substrates) was observed among the strains. The carbon catabolic profiles appeared to suggest that S. Typhi strains survived well on carbon subtrates that are found abundantly in the human body but not in others. The strains could not utilise plant-associated carbon substrates. In addition, α-glycerolphosphate, glycerol, L-serine, pyruvate and lactate served as better carbon sources to monosaccharides in the S. Typhi strains tested. Conclusion The carbon catabolic profiles suggest that S. Typhi could survive and persist well in the nutrient depleted metabolic niches in the human host but not in the environment outside of the host. These findings serve as caveats for future studies to understand how carbon catabolism relates to the pathogenesis and transmission of this pathogen. PMID:22662115

  9. Flagella-independent surface motility in Salmonella enterica serovar Typhimurium

    PubMed Central

    Park, Sun-Yang; Pontes, Mauricio H.; Groisman, Eduardo A.

    2015-01-01

    Flagella are multiprotein complexes necessary for swimming and swarming motility. In Salmonella enterica serovar Typhimurium, flagella-mediated motility is repressed by the PhoP/PhoQ regulatory system. We now report that Salmonella can move on 0.3% agarose media in a flagella-independent manner when experiencing the PhoP/PhoQ-inducing signal low Mg2+. This motility requires the PhoP-activated mgtA, mgtC, and pagM genes, which specify a Mg2+ transporter, an inhibitor of Salmonella’s own F1Fo ATPase, and a small protein of unknown function, respectively. The MgtA and MgtC proteins are necessary for pagM expression because pagM mRNA levels were lower in mgtA and mgtC mutants than in wild-type Salmonella, and also because pagM expression from a heterologous promoter rescued motility in mgtA and mgtC mutants. PagM promotes group motility by a surface protein(s), as a pagM-expressing strain conferred motility upon a pagM null mutant, and proteinase K treatment eliminated motility. The pagM gene is rarely found outside subspecies I of S. enterica and often present in nonfunctional allelic forms in organisms lacking the identified motility. Deletion of the pagM gene reduced bacterial replication on 0.3% agarose low Mg2+ media but not in low Mg2+ liquid media. Our findings define a form of motility that allows Salmonella to scavenge nutrients and to escape toxic compounds in low Mg2+ semisolid environments. PMID:25624475

  10. The perception of volcanic risk in Kona communities from Mauna Loa and Hualālai volcanoes, Hawai'i

    USGS Publications Warehouse

    Gregg, Chris E.; Houghton, B.F.; Johnston, David M.; Paton, Douglas; Swanson, D.A.

    2004-01-01

    Volcanic hazards in Kona (i.e. the western side of the island of Hawai'i) stem primarily from Mauna Loa and Huala??lai volcanoes. The former has erupted 39 times since 1832. Lava flows were emplaced in Kona during seven of these eruptions and last impacted Kona in 1950. Huala??lai last erupted in ca. 1800. Society's proximity to potential eruptive sources and the potential for relatively fast-moving lava flows, coupled with relatively long time intervals since the last eruptions in Kona, are the underlying stimuli for this study of risk perception. Target populations were high-school students and adults ( n =462). Using these data, we discuss threat knowledge as an influence on risk perception, and perception as a driving mechanism for preparedness. Threat knowledge and perception of risk were found to be low to moderate. On average, fewer than two-thirds of the residents were aware of the most recent eruptions that impacted Kona, and a minority felt that Mauna Loa and Huala??lai could ever erupt again. Furthermore, only about one-third were aware that lava flows could reach the coast in Kona in less than 3 h. Lava flows and ash fall were perceived to be among the least likely hazards to affect the respondent's community within the next 10 years, whereas vog (volcanic smog) was ranked the most likely. Less than 18% identified volcanic hazards as amongst the most likely hazards to affect them at home, school, or work. Not surprisingly, individual preparedness measures were found on average to be limited to simple tasks of value in frequently occurring domestic emergencies, whereas measures specific to infrequent hazard events such as volcanic eruptions were seldom adopted. Furthermore, our data show that respondents exhibit an 'unrealistic optimism bias' and infer that responsibility for community preparedness for future eruptions primarily rests with officials. We infer that these respondents may be less likely to attend to hazard information, react to warnings as

  11. Community preparedness for lava flows from Mauna Loa and Hualālai volcanoes, Kona, Hawai'i

    USGS Publications Warehouse

    Gregg, Chris E.; Houghton, Bruce F; Paton, Douglas; Swanson, Donald A.; Johnston, David M.

    2004-01-01

    Lava flows from Mauna Loa and Huala??lai volcanoes are a major volcanic hazard that could impact the western portion of the island of Hawai'i (e.g., Kona). The most recent eruptions of these two volcanoes to affect Kona occurred in A.D. 1950 and ca. 1800, respectively. In contrast, in eastern Hawai'i, eruptions of neighboring Ki??lauea volcano have occurred frequently since 1955, and therefore have been the focus for hazard mitigation. Official preparedness and response measures are therefore modeled on typical eruptions of Ki??lauea. The combinations of short-lived precursory activity (e.g., volcanic tremor) at Mauna Loa, the potential for fast-moving lava flows, and the proximity of Kona communities to potential vents represent significant emergency management concerns in Kona. Less is known about past eruptions of Huala??lai, but similar concerns exist. Future lava flows present an increased threat to personal safety because of the short times that may be available for responding. Mitigation must address not only the specific characteristics of volcanic hazards in Kona, but also the manner in which the hazards relate to the communities likely to be affected. This paper describes the first steps in developing effective mitigation plans: measuring the current state of people's knowledge of eruption parameters and the implications for their safety. We present results of a questionnaire survey administered to 462 high school students and adults in Kona. The rationale for this study was the long lapsed time since the last Kona eruption, and the high population growth and expansion of infrastructure over this time interval. Anticipated future growth in social and economic infrastructure in this area provides additional justification for this work. The residents of Kona have received little or no specific information about how to react to future volcanic eruptions or warnings, and short-term preparedness levels are low. Respondents appear uncertain about how to respond

  12. Salmonella infections in reptiles--prevalence, serovar spectrum and impact on animal health.

    PubMed

    Sting, Reinhard; Ackermann, Dorothee; Blazey, Birgit; Rabsch, Wolfgang; Szabo, Istvan

    2013-01-01

    In a seven year study, 235 lizards, 193 snakes and 111 chelonians were tested for the occurrence of Salmonella enterica. The material for analysis consisted of 251 faecal samples from reptiles suffering from diarrhoea and 288 carcasses of perished or euthanized reptiles. The carcasses were dissected and examined pathohistologically. A total of 35.3% of the lizards, 47.2% of the snakes and 11.7% of the chelonians were found to be Salmonella-positive. Systemic Salmonella infection was detected in 56.1% of the Salmonella-positive lizards and snakes carcasses; 67.4% of these were found to have pathohistological changes of varying severity in the affected organs. The relationship between the systemic Salmonella infection and pathohistological changes was highly significant. Furthermore, systemic Salmonella infections were accompanied by debilitating factors such as parasitic disease, husbandry-associated metabolic or degenerative diseases or viral infection in 63% of the cases. A total of 83 different serovars could be detected, of which 49 occurred in lizards, 36 in snakes and ten in chelonians. Infections with two Salmonella serovars were found in seven cases and in one case with three Salmonella serovars. One infection was associated with a previously undocumented Salmonella serovar in the faecal sample of a water dragon (Subsp. lllb,18:l,v,z13:z).

  13. Swarm and swim motilities of Salmonella enterica serovar Typhimurium and role of osmoregulated periplasmic glucans

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Salmonella enterica serovar Typhimurium strains synthesize osmoregulated periplasmic glucans (OPGs) under low osmolarity conditions (< 70 mos mol l-1). OPG synthesis is not observed when cells are grown in iso- or hyper-osmotic media (> 400 mos mol l-1). Mutation in OPG structural gene...

  14. Impact of sporadic reporting of poultry Salmonella serovars from selected developing countries.

    PubMed

    Barbour, Elie K; Ayyash, Danielle B; Alturkistni, Wafa; Alyahiby, Areej; Yaghmoor, Soonham; Iyer, Archana; Yousef, Jehad; Kumosani, Taha; Harakeh, Steve

    2015-01-15

    This review documents the sporadic reporting of poultry Salmonella serovars in South Africa, Egypt, Indonesia, India, and Romania, five countries selected based on the importance of their distribution in different regions of the world and their cumulative significant population size of 1.6 billion. South Africa reported contamination of its poultry carcasses by S. Hadar, S. Blockley, S. Irumu, and S. Anatum. Results from Egypt showed that S. Enteritidis and S. Typhimurium were predominant in poultry along with other non-typhoid strains, namely S. Infantis, S. Kentucky, S. Tsevie, S. Chiredzi, and S. Heidelberg. In Indonesia, the isolation of Salmonella Typhi was the main focus, while other serovars included S. Kentucky, S. Typhimurium, and S. Paratyhi C. In India, S. Bareilly was predominant compared to S. Enteritidis, S. Typhimurium, S. Paratyphi B, S. Cerro, S. Mbandaka, S. Molade, S. Kottbus, and S. Gallinarum. Romania reported two Salmonella serovars in poultry that affect humans, namely S. Enteritidis and S. Typhimurium, and other non-typhoid strains including S. Infantis, S. Derby, S. Colindale, S. Rissen, S. Ruzizi, S. Virchow, S. Brandenburg, S. Bredeney, S. Muenchen, S. Kortrijk, and S. Calabar. The results showed the spread of different serovars of Salmonella in those five developing countries, which is alarming and emphasizes the urgent need for the World Health Organization Global Foodborne Infections Network (WHO-GFN) to expand its activities to include more strategic participation and partnership with most developing countries in order to protect poultry and humans from the serious health impact of salmonellosis.

  15. Multiresistant Salmonella enterica serovar 4,[5],12:i:- in Europe: a new pandemic strain?

    PubMed

    Hopkins, K L; Kirchner, M; Guerra, B; Granier, S A; Lucarelli, C; Porrero, M C; Jakubczak, A; Threlfall, E J; Mevius, D J

    2010-06-03

    A marked increase in the prevalence of S. enterica serovar 4,[5],12:i:- with resistance to ampicillin, streptomycin, sulphonamides and tetracyclines (R-type ASSuT) has been noted in food-borne infections and in pigs/pig meat in several European countries in the last ten years. One hundred and sixteen strains of S. enterica serovar 4,[5],12:i:- from humans, pigs and pig meat isolated in England and Wales, France, Germany, Italy, Poland, Spain and the Netherlands were further subtyped by phage typing, pulsed-field gel electrophoresis and multilocus variable number tandem repeat analysis to investigate the genetic relationship among strains. PCR was performed to identify the fljB flagellar gene and the genes encoding resistance to ampicillin, streptomycin, sulphonamides and tetracyclines. Class 1 and 2 integrase genes were also sought. Results indicate that genetically related serovar 4,[5],12:i:- strains of definitive phage types DT193 and DT120 with ampicillin, streptomycin, sulphonamide and tetracycline resistance encoded by blaTEM, strA-strB, sul2 and tet(B) have emerged in several European countries, with pigs the likely reservoir of infection. Control measures are urgently needed to reduce spread of infection to humans via the food chain and thereby prevent the possible pandemic spread of serovar 4,[5],12:i:- of R-type ASSuT as occurred with S. Typhimurium DT104 during the 1990s.

  16. Complete Whole-Genome Sequence of Salmonella enterica subsp. enterica Serovar Java NCTC5706.

    PubMed

    Fazal, Mohammed-Abbas; Alexander, Sarah; Burnett, Edward; Deheer-Graham, Ana; Oliver, Karen; Holroyd, Nancy; Parkhill, Julian; Russell, Julie E

    2016-11-03

    Salmonellae are a significant cause of morbidity and mortality globally. Here, we report the first complete genome sequence for Salmonella enterica subsp. enterica serovar Java strain NCTC5706. This strain is of historical significance, having been isolated in the pre-antibiotic era and was deposited into the National Collection of Type Cultures in 1939.

  17. Complete Whole-Genome Sequence of Salmonella enterica subsp. enterica Serovar Java NCTC5706

    PubMed Central

    Fazal, Mohammed-Abbas; Burnett, Edward; Deheer-Graham, Ana; Oliver, Karen; Holroyd, Nancy; Russell, Julie E.

    2016-01-01

    Salmonellae are a significant cause of morbidity and mortality globally. Here, we report the first complete genome sequence for Salmonella enterica subsp. enterica serovar Java strain NCTC5706. This strain is of historical significance, having been isolated in the pre-antibiotic era and was deposited into the National Collection of Type Cultures in 1939. PMID:27811100

  18. TRANSCRIPTIONAL RESPONSE OF CHICKEN MACROPHAGES TO SALMONELLA ENTERICA SEROVAR ENTERITIDIS INFECTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The transcriptional profiles of chicken macrophages (HD11) infected with Salmonella enterica serovar Enteritidis (SE) were analyzed by using avian macrophage microarray and real time RT-PCR. Out of 4,906 array elements interrogated, 269 genes exhibited a 2-fold change (P < 0.001) over a 24-hour time...

  19. Transcriptional Response of Chicken Macrophages to Salmonella enterica serovar Enteritidis Infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar Enteritidis (SE) continues to be the predominant etiologic agent of salmonellosis, with contaminated egg products being the primary source of infection. At the present time, the molecular and immunological mechanisms involved in SE colonization of chicken hosts are not we...

  20. Antibiotics induce the expression of attachment genes in specific isolates of Salmonella enterica serovar Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More than 27 percent of Salmonella enterica serovar Typhimurium isolates from humans in the United States are resistant to three or more antibiotics. This presents an important food safety concern as multidrug-resistant (MDR) Salmonella is associated with increased morbidity in humans. It has been...

  1. Polynucleotide phosphorlyase (PNPase) is required for Salmonella enterica serovar Typhimurium colonization in swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The pnp gene encodes polynucleotide phosphorylase, an exoribonuclease involved in RNA degradation. A mutation in the pnp gene was previously identified by our group in a signature-tagged mutagenesis screen designed to search for Salmonella enterica serovar Typhimurium genes required for survival in...

  2. Tetracycline promotes the expression of ten fimbrial operons in specific Salmonella enterica serovar Typhimurium isolates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Multidrug-resistant (MDR) Salmonella is associated with increased morbidity in humans and presents an important food safety concern. Antibiotic resistance among isolates of Salmonella enterica serovar Typhimurium has become especially prevalent as over 27 per cent of isolates from humans in the Unit...

  3. Complete Genome Sequence and Methylome of Salmonella enterica subsp. enterica Cerro, a Frequent Dairy Cow Serovar.

    PubMed

    Haley, Bradd J; Pirone, Cary; Muruvanda, Tim; Brown, Eric; Allard, Marc; Karns, Jeffrey S; Van Kessel, Jo Ann S

    2016-01-28

    Salmonella enterica subsp. enterica serovar Cerro is an infrequent pathogen of humans and other mammals but is frequently isolated from the hindgut of asymptomatic cattle in the United States. To further understand the genomic determinants of S. Cerro specificity for the bovine hindgut, the genome of isolate CFSAN001588 was fully sequenced and deposited in the GenBank database.

  4. Inactivation of Salmonella serovars by Pseudomonas chlororaphis and Pseudomonas fluorescens strains on tomatoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica and its serovars have been associated with pathogen contamination of tomatoes and numerous outbreaks of Salmonellisis. To improve food safety, pathogen control is of immediate concern. The aim of this reserach was to: 1) Assess the populations of natural microflora (aerobic meso...

  5. Identification of Genes Affecting Salmonella enterica Serovar Enteritidis Infection of Chicken Macrophages

    PubMed Central

    Zhao, Yixian; Jansen, Ruud; Gaastra, Wim; Arkesteijn, Ger; van der Zeijst, Bernard A. M.; van Putten, Jos P. M.

    2002-01-01

    Screening of 7,680 Salmonella enterica serovar Enteritidis mutants for attenuation in a chicken macrophage infection model yielded a series of mutants including several with defects in previously unrecognized Salmonella virulence genes. One of the newly identified genes was the pbpA2 gene, belonging to the penicillin binding protein gene family. PMID:12183592

  6. Chlamydia trachomatis serovar G infection in a bisexual male with urethritis.

    PubMed

    Rawre, Jyoti; Dhawan, Benu; Saigal, Karnika; Khanna, Neena

    2016-01-01

    We report a case of Chlamydia trachomatis serovar G urogenital tract infection in a 33-year-old human immunodeficiency virus-1 (HIV-1) seropositive Indian bisexual male. This case highlights the emergence of a new serovar in India. The patient was tested positive for C. trachomatis by both cryptic plasmid and omp A gene polymerase chain reaction (PCR). On further characterization using polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) and omp A gene sequencing, the strain was found to be C. trachomatis serovar G. His spouse was also found to be infected with C. trachomatis serovar G. Phylogenetic analysis was performed on the clinical isolates obtained from both partners and were found to be identical to the isolates available in GenBank. The sexual network could not be traced further. Detection of a new genotype suggests importation of a new strain into the population probably by sexual contact with a person from a geographical area where the strain is common. Identifying circulating genotypes in the community can assist in developing strategies for improved sexually transmitted disease control.

  7. SALMONELLA ENTERICA SEROVAR ENTERITIDIS INFECTION MODULATES DIVERSE FUNCTIONAL PROCESSES OF CHICKEN MACROPHAGE AT THE TRANSCRIPTIONAL LEVEL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar Enteritidis (SE) is a major etiologic agent of non-typhoid salmonellosis. The organisms colonize adult chicken hosts without causing overt clinical signs. The immunological mechanisms underlying the silent and persistent infection of chickens by SE are not clearly underst...

  8. Comparison of avian Chlamydia psittaci isolates by restriction endonuclease analysis and serovar-specific monoclonal antibodies.

    PubMed Central

    Andersen, A A

    1991-01-01

    Avian Chlamydia psittaci isolates were examined by restriction endonuclease analysis and serovar-specific monoclonal antibodies and compared with ovine abortion and polyarthritis isolates. The avian isolates were divided into four serovars (turkey, psittacine, pigeon, and duck) based on their reactivity to the monoclonal antibodies. The DNA digest patterns were similar across the four avian serovars; most bands were identical when the isolates were tested with PstI, BamHI, and EcoRI restriction endonuclease enzymes. The turkey group restriction endonuclease analysis patterns were distinguished from those of the other avian strains by three to four band differences with all enzymes. The duck and pigeon isolates showed only minor DNA pattern differences when compared with the psittacine isolates. Four psittacine isolates from various locations in Texas had an extra band with the EcoRI restriction enzyme, suggesting that they were from a common source; however, they were indistinguishable from the other psittacine isolates when examined with the monoclonal antibodies. The avian isolates were distinctly different from either abortion or polyarthritis isolates by both restriction endonuclease analysis and monoclonal antibody analysis. The data demonstrate that the avian isolates form a distinct group or separate biovar with at least four serovars. Images PMID:1848867

  9. Hydrogen-Stimulated carbon acquisition and conservation in salmonella enterica serovar typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar Typhimurium can utilize molecular hydrogen for growth and amino acid transport during anaerobic growth. Via microarray we identified H2 gas-affected gene expression changes in Salmonella. Addition of H2 caused altered expression of 965 genes; 176 genes were H2-up-regulate...

  10. Whole-Genome Shotgun Sequencing of Cephalosporin-Resistant Salmonella enterica Serovar Typhi.

    PubMed

    Rodrigues, Camilla; Kapil, Arti; Sharma, Anita; Devanga Ragupathi, Naveen Kumar; Inbanathan, Francis Yesurajan; Veeraraghavan, Balaji; Kang, Gagandeep

    2017-03-09

    Typhoid is one of the leading causes of mortality in developing countries. Here, we report the draft genome sequences of four Salmonella enterica serovar Typhi strains isolated from bloodstream infections in a tertiary care hospital. The sequence data indicate genomes of ~4.5 Mb for all isolates, with one plasmid in each.

  11. Natural surface coating to inactivate Salmonella enterica Serovar Typhimurium and maintain quality of cherry tomatoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objectives of the present study were to investigate the effectiveness of zein-based coatings in reducing populations of Salmonella enterica serovar Typhimurium and preserving quality of cherry tomatoes. Tomatoes were inoculated with a cocktail of S. Typhimurium LT2 plus three mutants on the smoo...

  12. Genomic heterogeneity of Salmonella enterica serovar Typhimurium bacteriuria from chronic infection.

    PubMed

    Octavia, Sophie; Wang, Qinning; Tanaka, Mark M; Sintchenko, Vitali; Lan, Ruiting

    2017-03-07

    We sequenced the genomes of 14 sequential Salmonella enterica serovar Typhimurium isolates obtained over a five year period from a patient with persistent Salmonella bacteriuria. The isolates formed five distinct lineages; two of which co-existed over four years. We inferred that the observed within-patient variation resulted from mutation events.

  13. Whole-Genome Shotgun Sequencing of Cephalosporin-Resistant Salmonella enterica Serovar Typhi

    PubMed Central

    Rodrigues, Camilla; Kapil, Arti; Sharma, Anita; Devanga Ragupathi, Naveen Kumar; Inbanathan, Francis Yesurajan; Kang, Gagandeep

    2017-01-01

    ABSTRACT Typhoid is one of the leading causes of mortality in developing countries. Here, we report the draft genome sequences of four Salmonella enterica serovar Typhi strains isolated from bloodstream infections in a tertiary care hospital. The sequence data indicate genomes of ~4.5 Mb for all isolates, with one plasmid in each. PMID:28280021

  14. Cytotoxic mechanism of cytolethal distending toxin in nontyphoidal Salmonella serovar (Salmonella Javiana) during macrophage infection.

    PubMed

    Williams, Katherine; Gokulan, Kuppan; Shelman, Diamond; Akiyama, Tatsuya; Khan, Ashraf; Khare, Sangeeta

    2015-02-01

    Cytolethal distending toxin B (cdtB) is a conserved virulence factor in Salmonella enterica serovar Typhi. Here we report the presence and functionality of cdtB in some nontyphoidal Salmonella (NTS) serovars, including Salmonella Javiana (cdtB+wt S. Javiana), isolated from imported food. To understand the role of cdtB in NTS serovars, a deletion mutant (cdtB(-)ΔS. Javiana) was constructed. Macrophages were infected with cdtB+wt S. Javiana (wild type), cdtB(-)Δ S. Javiana (mutant), and cdtB-negative NTS serovar (S. Typhimurium). Cytotoxic activity and transcription level of genes involved in cell death (apoptosis, autophagy, and necrosis) were assessed in infected macrophages. The cdtB+wt S. Javiana caused cellular distension as well as high degree of vacuolization and presence of the autophagosome marker LC3 in infected macrophages as compared with cdtB(-)ΔS. Javiana. The mRNA expression of genes involved in the induction of autophagy in response to toxin (Esr1 and Pik3C3) and coregulators of autophagy and apoptosis (Bax and Cyld) were significantly upregulated in cdtB(+)wt S. Javiana-infected macrophages. As autophagy destroys internalized pathogens in addition to the infected cell, it may reduce the spread of infection.

  15. Whole-Genome Sequencing of Salmonella enterica subsp. enterica Serovar Cubana Strains Isolated from Agricultural Sources

    PubMed Central

    Benahmed, Faiza H.; Gopinath, Gopal R.; Wang, Hua; Jean-Gilles Beaubrun, Junia; Grim, Christopher; Cheng, Chorng-Ming; McClelland, Michael; Ayers, Sherry; Abbott, Jason; Desai, Prerak; Frye, Jonathan G.; Weinstock, George; Hammack, Thomas S.; Hanes, Darcy E.; Rasmussen, Mark A.

    2014-01-01

    We report the draft genomes of Salmonella enterica subsp. enterica serovar Cubana strain CVM42234, isolated from chick feed in 2012, and S. Cubana strain 76814, isolated from swine in 2004. The genome sizes are 4,975,046 and 4,936,251 bp, respectively. PMID:24459266

  16. Efficacy of the Rabbit Polyclonal Anti-leptospira Antibody against Homotype or Heterotype Leptospira Infection in Hamster

    PubMed Central

    Ding, Zhuang; Wang, Hai; Wu, Dianjun; Xie, Xufeng; Lin, Tao; Fu, Yunhe; Zhang, Naisheng; Cao, Yongguo

    2016-01-01

    Leptospirosis, caused by Leptospira, is one of the most important of neglected emerging zoonotic diseases that has important impacts on public health worldwide. Polyclonal antibody (pcAb) therapy is a potential method to process a series of pathogens for which there are limited determination of treatment, such as leptospirosis. First, we evaluated the efficacy of pcAb, derived from the sera of rabbits inoculated with Leptospira, against homotype (Leptospira interrogans serovar Lai) or heterotype (Leptospira interrogans serovar Autumnalis) Leptospira infection in a lethal hamster model. The pcAb treatment improved survival compared to the controls. The histopathology’s of the infected kidney, liver and lung were also examined by hematoxylin and eosin staining. Using real-time quantitative PCR, we determined that most of the leptospires in the primary organs were almost completely removed by pcAb. In the second experiment, treatments, including antibiotic, pcAb, and combination, were started immediately after occurrence of the first serious sickness mouse in any group. No significant difference in survival rate between pcAb group and antibiotic group was found, but the combination therapy group significantly improved survival rate compared to the others (P<0.05). We conclude that the rabbit pcAb treatment may cure both the homotype and the heterotype lethal Leptospira infections in hamster, and combination therapy improved survival compared to antibiotic group in the late treatment of homotype leptospirosis. PMID:28027297

  17. Differential antibacterial response of chicken granulosa cells to invasion by Salmonella serovars.

    PubMed

    Babu, Uma S; Harrison, Lisa M; Patel, Isha R; Ramirez, Gerardo A; Williams, Kristina M; Pereira, Marion; Balan, Kannan V

    2016-06-01

    In the United States, Salmonella enterica ser. Enteritidis (SE) is among the leading bacterial cause of foodborne illness via consumption of raw or undercooked eggs. The top Salmonella serovars implicated in U.S. foodborne outbreaks associated with chicken consumption include SE, Typhimurium (ST), Heidelberg (SH), Montevideo, Mbandka, Braenderup, and Newport. While enforcement actions target the eradication of SE from layer hens, there is a growing concern that other serovars could occupy this niche and be a cause of egg-transmitted human salmonellosis. Therefore, we tested the invasion and survival of SE, SH, ST, and Salmonella enterica ser. Hadar (S. Hadar) at 4 and 20 h post infection (hpi) in chicken ovarian granulosa cells (cGC); a cellular layer which surrounds the previtelline layer and central yolk in egg-forming follicles. We also evaluated cGC transcriptional changes, using an antibacterial response PCR array, to assess host response to intracellular SalmonellaWe observed that invasion of cGC by SE, SH, and ST was significantly higher than invasion by S. Hadar, with ST showing the highest level of invasion. The Bacterial Survival Index, defined as the ratio of intracellular bacteria at 20 and 4 h, were 18.94, 7.35, and 15.27 for SE, SH, and ST, respectively, with no significant difference in survival between SE or ST compared to SH. Evaluation of cGC anti-Salmonella gene responses indicated that at 4 hpi there was a significant decrease in Toll-like receptor (TLR)-4 mRNA in cGC infected with SE, whereas TLR5 and myeloid differentiation primary response gene 88 were significantly down regulated across all serovars. At 4 hpi, invasion by Salmonella serovars resulted in significant upregulation of several antimicrobial genes, and proinflammatory cytokines and chemokines (PICs). At 20 hpi, all the serovars induced PICs with SH being the strongest inducer. Additionally, SE, SH and ST differentially induced signal transduction pathways. Although only a single

  18. Antimicrobial Resistance of Salmonella enterica Serovar Typhimurium in Shanghai, China

    PubMed Central

    Wang, Jinyan; Li, Yongrui; Xu, Xuebin; Liang, Beibei; Wu, Fuli; Yang, Xiaoxia; Ma, Qiuxia; Yang, Chaojie; Hu, Xiaofeng; Liu, Hongbo; Li, Hao; Sheng, Chunyu; Xie, Jing; Du, Xinying; Hao, Rongzhang; Qiu, Shaofu; Song, Hongbin

    2017-01-01

    We aimed to analyze the antimicrobial resistance phenotypes and to elucidate the molecular mechanisms underlying resistance to cephalosporins, ciprofloxacin, and azithromycin in Salmonella enterica serovar Typhimurium isolates identified from patients with diarrhea in Shanghai. The isolates showed high rates of resistance to traditional antimicrobials, and 20.6, 12.7, and 5.5% of them exhibited decreased susceptibility to cephalosporins, ciprofloxacin, and azithromycin, respectively. Notably, 473 (84.6%) isolates exhibited multidrug resistance (MDR), including 161 (28.8%) isolates that showed an ACSSuT profile. Twenty-two MDR isolates concurrently exhibited decreased susceptibility to cephalosporins and ciprofloxacin, and six of them were co-resistant to azithromycin. Of all the 71 isolates with decreased susceptibility to ciprofloxacin, 65 showed at least one mutation (D87Y, D87N, or D87G) in gyrA, among which seven isolates simultaneously had mutations of parC (S80R) (n = 6) or parC (T57S/S80R) (n = 1), while 49 isolates with either zero or one mutation in gyrA contained plasmid-mediated quinolone resistance (PMQR) genes including qnrB, qnrS, and aac(6′)-Ib-cr. Among the 115 cephalosporin-resistant isolates, the most common ESBL gene was blaCTX-M, followed by blaTEM-1, blaOXA-1, and blaSHV -12. Eight subtypes of blaCTX-M were identified and blaCTX-M-14 (n = 22) and blaCTX-M-55 (n = 31) were found to be dominant. To the best of our knowledge, this is the first report of the presence of blaCTX-M-123 and blaCTX-M-125 in S. Typhimurium. Besides, mphA gene was identified in 15 of the 31 azithromycin-resistant isolates. Among the 22 isolates with reduced susceptibility to cephalosporins and ciprofloxacin, 15 contained ESBL and PMQR genes. Coexistence of these genes lead to the emergence of MDR and the transmission of them will pose great difficulties in S. Typhimurium treatments. Therefore, surveillance for these MDR isolates should be enhanced.

  19. Biogeochemical characteristics of Kuan-Tzu-Ling, Chung-Lun and Bao-Lai hot springs in southern Taiwan.

    PubMed

    Maity, Jyoti Prakash; Liu, Chia-Chuan; Nath, Bibhash; Bundschuh, Jochen; Kar, Sandeep; Jean, Jiin-Shuh; Bhattacharya, Prosun; Liu, Jiann-Hong; Atla, Shashi B; Chen, Chien-Yen

    2011-01-01

    Hot springs are the important natural sources of geothermally heated groundwater from the Earth's crust. Kuan-Tzu-Ling (KTL), Chung-Lun (CL) and Bao-Lai (BL) are well-known hot springs in southern Taiwan. Fluid and mud (sediments) samples were collected from the eruption points of three hot springs for detailed biogeochemical characterization. The fluid sample displays relatively high concentrations of Na(+) and Cl(-) compared with K(+), Mg(2+), Ca(2+), NO(2) (-), and SO(4) (2-), suggesting a possible marine origin. The concentrations of Fe, Cr, Mn, Ni, V and Zn were significantly higher in the mud sediments compared with fluids, whereas high concentrations of As, Ba, Cu, Se, Sr and Rb were observed in the fluids. This suggests that electronegative elements were released during sediment-water interactions. High As concentration in the fluids was observed to be associated with low redox (Eh) conditions. The FTIR spectra of the humic acid fractions of the sediments showed the presence of possible functional groups of secondary amines, ureas, urethanesm (amide), and silicon. The sulfate-reducing deltaproteobacterium 99% similar to Desulfovibrio psychrotolerans (GU329907) were rich in the CL hot spring while mesophilic, proteolytic, thiosulfate- and sulfur-reducing bacterium that 99% similar to Clostridium sulfidigenes (GU329908) were rich in the BL hot spring.

  20. Lipopolysaccharides belonging to different Salmonella serovars are differentially capable of activating Toll-like receptor 4.

    PubMed

    Chessa, Daniela; Spiga, Luisella; De Riu, Nicola; Delaconi, Paola; Mazzarello, Vittorio; Ganau, Giulia; Rubino, Salvatore

    2014-11-01

    Salmonella enterica subsp. enterica serovar (serotype) Abortusovis is a member of the Enterobacteriaceae. This serotype is naturally restricted to ovine species and does not infect humans. Limited information is available about the immune response of sheep to S. Abortusovis. S. Abortusovis, like Salmonella enterica subsp. enterica serovar Typhi, causes a systemic infection in which, under natural conditions, animals are not able to raise a rapid immune response. Failure to induce the appropriate response allows pathogens to reach the placenta and results in an abortion. Lipopolysaccharides (LPSs) are pathogen-associated molecular patterns (PAMPs) that are specific to bacteria and are not synthesized by the host. Toll-like receptors (TLRs) are a family of receptors that specifically recognize PAMPs. As a first step, we were able to identify the presence of Toll-like receptor 4 (TLR4) on the ovine placenta by using an immunohistochemistry technique. To our knowledge, this is the first work describing the interaction between S. Abortusovis LPS and TLR4. Experiments using an embryonic cell line (HEK293) transfected with human and ovine TLR4s showed a reduction of interleukin 8 (IL-8) production by S. Abortusovis and Salmonella enterica subsp. enterica serovar Paratyphi upon LPS stimulation compared to Salmonella enterica subsp. enterica serovar Typhimurium. Identical results were observed using heat-killed bacteria instead of LPS. Based on data obtained with TLR4 in vitro stimulation, we demonstrated that the serotype S. Abortusovis is able to successfully evade the immune system whereas S. Typhimurium and other serovars fail to do so.

  1. Evaluation of the ERIC-PCR as a probable method to differentiate Avibacterium paragallinarum serovars.

    PubMed

    Hellmuth, Julius Eduard; Hitzeroth, Arina Corli; Bragg, Robert Richard; Boucher, Charlotte Enastacia

    2016-11-21

    Infectious coryza an upper respiratory tract-disease in chickens, caused by Avibacterium paragallinarum, leads to huge economic losses. The disease is controlled through vaccination, but vaccination efficacy is dependent on correct identification of the infecting serovar, as limited cross-protection is reported amongst some serovars. Current identification methods include the heamagglutination inhibition (HI) test, which is demanding, and could be subjective. To overcome this, molecular typing methods proposed are the Multiplex PCR and Restriction Fragment Length Polymorphism (RFLP) PCR, but low reproducibility is reported. Enterobacterial Repetitive Intergenic Consensus (ERIC) PCR has been suggested for molecular groupings of various bacterial species. This study focuses on evaluating the ERIC-PCR as probable method to differentiate between different Av. paragallinarum serovars by grouping with reference isolates, based on clonal relations. The ERIC-PCR was performed on 12 reference isolates and 41 field isolates originating from South Africa and South America. The data indicates that the ERIC-PCR is not ideal for the differentiation nor molecular typing of Av. paragallinarum serovars, as no correlation is drawn upon comparison of banding patterns of field isolates and reference strains. However, the results do indicate isolates from the same origin sharing unique banding patterns, indicating potential clonal relationship, but when compared to the reference isolates dominant in the specific area, no correlation could be drawn. Furthermore, although the ERIC-PCR serves a purpose in epidemiological studies, it has proved to have little application in differentiating amongst serovars of Av. paragallinarum and to group untyped field strains with known reference strains.

  2. Clinical and veterinary isolates of Salmonella enterica serovar Enteritidis defective in lipopolysaccharide O-chain polymerization

    SciTech Connect

    Guard-Petter, J.; Parker, C.T.; Asokan, K.; Carlson, R.W.

    1999-05-01

    Twelve human and chicken isolates of Salmonella enterica serovar Enteritidis belonging to phage types 4, 8, 13a, and 23 were characterized for variability in lipopolysaccharide (LPS) composition. Isolates were differentiated into two groups, i.e., those that lacked immunoreactive O-chain, termed rough isolates, and those that had immunoreactive O-chain, termed smooth isolates. Isolates within these groups could be further differentiated by LPS compositional differences as detected by gel electrophoresis and gas liquid chromatography of samples extracted with water, which yielded significantly more LPS in comparison to phenol-chloroform extraction. The rough isolates were of two types, the O-antigen synthesis mutants and the O-antigen polymerization (wzy) mutants. Smooth isolates were also of two types, one producing low-molecular-weight (LMW) LPS and the other producing high-molecular-weight (HMW) LPS. To determine the genetic basis for the O-chain variability of the smooth isolates, the authors analyzed the effects of a null mutation in the O-chain length determinant gene, wzz (cld) of serovar Typhimurium. This mutation results in a loss of HMW LPS; however, the LMW LPS of this mutant was longer and more glucosylated than that from clinical isolates of serovar Enteritidis. Cluster analysis of these data and of those from two previously characterized isogenic strains of serovar Enteritidis that had different virulence attributes indicated that glucosylation of HMW LPS (via oafR function) is variable and results in two types of HMW structures, one that is highly glucosylated and one that is minimally glucosylated. These results strongly indicate that naturally occurring variability in wzy, wzz, and oafR function can be used to subtype isolates of serovar Enteritidis during epidemiological investigations.

  3. Analysis of a Spontaneous Non-Motile and Avirulent Mutant Shows That FliM Is Required for Full Endoflagella Assembly in Leptospira interrogans

    PubMed Central

    Fontana, Célia; Lambert, Ambroise; Benaroudj, Nadia; Gasparini, David; Gorgette, Olivier; Cachet, Nathalie; Bomchil, Natalia; Picardeau, Mathieu

    2016-01-01

    Pathogenic Leptospira strains are responsible for leptospirosis, a worldwide emerging zoonotic disease. These spirochetes are unique amongst bacteria because of their corkscrew-like cell morphology and their periplasmic flagella. Motility is reported as an important virulence determinant, probably favoring entry and dissemination of pathogenic Leptospira in the host. However, proteins constituting the periplasmic flagella and their role in cell shape, motility and virulence remain poorly described. In this study, we characterized a spontaneous L. interrogans mutant strain lacking motility, correlated with the loss of the characteristic hook-shaped ends, and virulence in the animal model. Whole genome sequencing allowed the identification of one nucleotide deletion in the fliM gene resulting in a premature stop codon, thereby preventing the production of flagellar motor switch protein FliM. Genetic complementation restored cell morphology, motility and virulence comparable to those of wild type cells. Analyses of purified periplasmic flagella revealed a defect in flagella assembly, resulting in shortened flagella compared to the wild type strain. This also correlated with a lower amount of major filament proteins FlaA and FlaB. Altogether, these findings demonstrate that FliM is required for full and correct assembly of the flagella which is essential for motility and virulence. PMID:27044038

  4. Precipitation of Iron on the Surface of Leptospira interrogans Is Associated with Mutation of the Stress Response Metalloprotease HtpX

    PubMed Central

    Henry, Rebekah; Lo, Miranda; Khoo, Chenai; Zhang, Hailong; Boysen, Reinhard I.; Picardeau, Mathieu; Murray, Gerald L.; Bulach, Dieter M.

    2013-01-01

    High concentrations of free metal ions in the environment can be detrimental to bacterial survival. However, bacteria utilize strategies, including the activation of stress response pathways and immobilizing chemical elements on their surface, to limit this toxicity. In this study, we characterized LA4131, the HtpX-like M48 metalloprotease from Leptospira interrogans, with a putative role in bacterial stress response and membrane homeostasis. Growth of the la4131 transposon mutant strain (L522) in 360 μM FeSO4 (10-fold the normal in vitro concentration) resulted in the production of an amorphous iron precipitate. Atomic force microscopy and transmission electron microscopy analysis of the strain demonstrated that precipitate production was associated with the generation and release of outer membrane vesicles (OMVs) from the leptospiral surface. Transcriptional studies indicated that inactivation of la4131 resulted in altered expression of a subset of metal toxicity and stress response genes. Combining these findings, this report describes OMV production in response to environmental stressors and associates OMV production with the in vitro activity of an HtpX-like metalloprotease. PMID:23709510

  5. Efficacy and mechanism of action of yin lai tang (lung-stomach treatment) in dyspepsia mouse infected by FM1 virus.

    PubMed

    Liu, Tiegang; Yu, He; Zhang, Wang; Zhen, Jianhua; Li, Xiaofei; Lv, Guokai; Gu, Hong-Xiao; Murtaza, Ghulam

    2013-01-01

    The aim of this study was to assess the efficacy and elaborate the mechanism of action of Yin Lai Tang (Lung-Stomach Treatment) on dyspepsia mouse infected by FM1 virus. Ninety male, 4 week old Kunming mouse with 12-14 g weight, were randomly divided into 9 groups, i.e., normal, infected, dyspepsia, ribavirin, Shuanghuanglian, Children's indigestion tablet, YinLaiTang high dose, YinLaiTang middle dose and YinLaiTang low dose, and these groups had been treated by according drugs to get objectives. Compared with normal group, lung index significantly (p < 0.01) increased in all groups except ribavirin group where lung index obviously (p < 0.05) increased. There was non-significant (p > 0.05) difference in the values of lung homogenate virus titer between dyspepsia group and other groups. Compared to normal group, there was variable degree of inflammatory cell infiltrations in respiratory tract structures in the animals of other groups, and there was a significant (p < 0.01) increase in the level of serum IL-6, IL-10, and TNF-alpha in infected and dyspepsia group and significant (p < 0.01) decrease in the level of serum IFN-gamma was observed. Compared with single clearing stomach method and single clearing lung approach, lung-stomach treatment reduced the level of IL-6 with non-significant difference (p > 0.05) and increased the level of IL-10 obviously, and compared with the single clearing lung method, there was a significant difference (p < 0.05). Compared with the single clearing stomach method and the single clearing lung method, the lung-stomach treatment method had a better efficacy and showed effects on the expression of pro-inflammatory factor and anti-inflammatory factor.

  6. Comparison of satellite-derived LAI and precipitation anomalies over Brazil with a thermal infrared-based Evaporative Stress Index for 2003-2013

    NASA Astrophysics Data System (ADS)

    Anderson, Martha C.; Zolin, Cornelio A.; Hain, Christopher R.; Semmens, Kathryn; Tugrul Yilmaz, M.; Gao, Feng

    2015-07-01

    Shortwave vegetation index (VI) and leaf area index (LAI) remote sensing products yield inconsistent depictions of biophysical response to drought and pluvial events that have occurred in Brazil over the past decade. Conflicting reports of severity of drought impacts on vegetation health and functioning have been attributed to cloud and aerosol contamination of shortwave reflectance composites, particularly over the rainforested regions of the Amazon basin which are subject to prolonged periods of cloud cover and episodes of intense biomass burning. This study compares timeseries of satellite-derived maps of LAI from the Moderate Resolution Imaging Spectroradiometer (MODIS) and precipitation from the Tropical Rainfall Mapping Mission (TRMM) with a diagnostic Evaporative Stress Index (ESI) retrieved using thermal infrared remote sensing over South America for the period 2003-2013. This period includes several severe droughts and floods that occurred both over the Amazon and over unforested savanna and agricultural areas in Brazil. Cross-correlations between absolute values and standardized anomalies in monthly LAI and precipitation composites as well as the actual-to-reference evapotranspiration (ET) ratio used in the ESI were computed for representative forested and agricultural regions. The correlation analyses reveal strong apparent anticorrelation between MODIS LAI and TRMM precipitation anomalies over the Amazon, but better coupling over regions vegetated with shorter grass and crop canopies. The ESI was more consistently correlated with precipitation patterns over both landcover types. Temporal comparisons between ESI and TRMM anomalies suggest longer moisture buffering timescales in the deeper rooted rainforest systems. Diagnostic thermal-based retrievals of ET and ET anomalies, such as used in the ESI, provide independent information on the impacts of extreme hydrologic events on vegetation health in comparison with VI and precipitation-based drought

  7. IS200 and multilocus sequence typing for the identification of Salmonella enterica serovar Typhi strains from Indonesia.

    PubMed

    Martínez-Gamboa, Areli; Silva, Claudia; Fernández-Mora, Marcos; Wiesner, Magdalena; Ponce de León, Alfredo; Calva, Edmundo

    2015-06-01

    In this work, IS200 and multi-locus sequence typing (MLST) were used to analyze 19 strains previously serotyped as Salmonella enterica serovar Typhi and isolated in Indonesia (16 strains), Mexico (2 strains), and Switzerland (1 strain). Most of the strains showed the most common Typhi sequence types, ST1 and ST2, and a new Typhi genotype (ST1856) was described. However, one isolate from Mexico and another from Indonesia were of the ST365 and ST426 sequence types, indicating that they belonged to serovars Weltevreden and Aberdeen, respectively. These results were supported by the amplification of IS200 fragments, which rapidly distinguish Typhi from other serovars. Our results demonstrate the utility of IS200 and MLST in the classification of Salmonella strains into serovars. These methods provide information on the clonal relatedness of strains isolated worldwide.

  8. Draft Genome Sequences of 18 Salmonella enterica subsp. enterica Serovar Oranienburg Strains Isolated from Rivers in Northwestern Mexico.

    PubMed

    Casteñeda-Ruelas, Gloria M; Carreón-Gaxiola, César; Castelán-Sánchez, Hugo G; Acatzi-Silva, Abraham; Romero-Martínez, Salvador; García-Molina, Alejandra; Jiménez-Edeza, Maribel

    2017-03-09

    Salmonella enterica subsp. enterica serovar Oranienburg is recognized as a foodborne pathogen widely distributed in the environment. Here, we report 18 draft genomes of S Oranienburg strains isolated from rivers in the northwestern region of Mexico.

  9. Integrative analysis of Salmonellosis in Israel reveals association of Salmonella enterica Serovar 9,12:l,v:- with extraintestinal infections, dissemination of endemic S. enterica Serovar Typhimurium DT104 biotypes, and severe underreporting of outbreaks.

    PubMed

    Marzel, Alex; Desai, Prerak T; Nissan, Israel; Schorr, Yosef Ilan; Suez, Jotham; Valinsky, Lea; Reisfeld, Abraham; Agmon, Vered; Guard, Jean; McClelland, Michael; Rahav, Galia; Gal-Mor, Ohad

    2014-06-01

    Salmonella enterica is the leading etiologic agent of bacterial food-borne outbreaks worldwide. This ubiquitous species contains more than 2,600 serovars that may differ in their host specificity, clinical manifestations, and epidemiology. To characterize salmonellosis epidemiology in Israel and to study the association of nontyphoidal Salmonella (NTS) serovars with invasive infections, 48,345 Salmonella cases reported and serotyped at the National Salmonella Reference Center between 1995 and 2012 were analyzed. A quasi-Poisson regression was used to identify irregular clusters of illness, and pulsed-field gel electrophoresis in conjunction with whole-genome sequencing was applied to molecularly characterize strains of interest. Three hundred twenty-nine human salmonellosis clusters were identified, representing an annual average of 23 (95% confidence interval [CI], 20 to 26) potential outbreaks. We show that the previously unsequenced S. enterica serovar 9,12:l,v:- belongs to the B clade of Salmonella enterica subspecies enterica, and we show its frequent association with extraintestinal infections, compared to other NTS serovars. Furthermore, we identified the dissemination of two prevalent Salmonella enterica serovar Typhimurium DT104 clones in Israel, which are genetically distinct from other global DT104 isolates. Accumulatively, these findings indicate a severe underreporting of Salmonella outbreaks in Israel and provide insights into the epidemiology and genomics of prevalent serovars, responsible for recurring illness.

  10. Multiplex PCR Assay for Detection of Vibrio vulnificus Biotype 2 and Simultaneous Discrimination of Serovar E Strains▿

    PubMed Central

    Sanjuán, Eva; Amaro, Carmen

    2007-01-01

    In the present work we develop a multiplex PCR assay for the detection and identification of the fish pathogen Vibrio vulnificus biotype 2 with discriminating potential for zoonotic strains (serovar E). The PCR assay allowed the identification of two new biotype 2 serovar E human isolates from culture collections. Finally, the multiplex was successfully applied to both diagnosis and carrier detection in field samples. PMID:17277209

  11. Prevalence, numbers and antimicrobial susceptibilities of Salmonella serovars and Campylobacter spp. in retail poultry in Phnom Penh, Cambodia.

    PubMed

    Lay, Kruy Sun; Vuthy, Yith; Song, Ping; Phol, Khem; Sarthou, Jean Louis

    2011-03-01

    Salmonella and Campylobacter are common bacterial pathogens associated with human gastro-enteritis; and raw poultry is considered to be an important source of these bacteria. To evaluate whether the Salmonella serovars and Campylobacter spp. bacteria could be monitored for the purpose of microbial presence, enumeration and antimicrobial resistance in raw poultry, 152 poultry carcasses were randomly selected from 10 markets in retail outlets of Phnom Penh during March 2006 to February 2007. The majority of poultry samples was contaminated by Salmonella serovars (88.2%) and Campylobacter spp. (80.9%). A very high contamination of Salmonella was found at 3-4 log₁₀ CFU/g for 22.4% of samples and of Campylobacter at 7-8 log₁₀ CFU/g for 1.3% of samples. Fifty nine different Salmonella serovars contaminated 134 poultry carcasses; five most prevalent serovars covered 29.1% of serovars isolates (Anatum, Typhimurium, Corvallis, Stanley and Enteritidis). Three Campylobacter species contaminating 123 raw poultry were Campylobacter jejuni (50.0%), Campylobacter coli (29.0%) and Campylobacter lari (21.0%). High antibiotic resistance percentages were found among Salmonella serovars and Campylobacter spp. isolates. This study revealed that raw poultry at the retail outlets in Phnom Penh markets are contaminated with high prevalences of food-borne pathogens, and communicating the importance of minimizing this risk in reducing human infections.

  12. Leptospira Serovars for Diagnosis of Leptospirosis in Humans and Animals in Africa: Common Leptospira Isolates and Reservoir Hosts

    PubMed Central

    Mgode, Georgies F.; Machang’u, Robert S.; Mhamphi, Ginethon G.; Katakweba, Abdul; Mulungu, Loth S.; Durnez, Lies; Leirs, Herwig; Hartskeerl, Rudy A.; Belmain, Steven R.

    2015-01-01

    The burden of leptospirosis in humans and animals in Africa is higher than that reported from other parts of the world. However, the disease is not routinely diagnosed in the continent. One of major factors limiting diagnosis is the poor availability of live isolates of locally circulating Leptospira serovars for inclusion in the antigen panel of the gold standard microscopic agglutination test (MAT) for detecting antibodies against leptospirosis. To gain insight in Leptospira serovars and their natural hosts occurring in Tanzania, concomitantly enabling the improvement of the MAT by inclusion of fresh local isolates, a total of 52 Leptospira isolates were obtained from fresh urine and kidney homogenates, collected between 1996 and 2006 from small mammals, cattle and pigs. Isolates were identified by serogrouping, cross agglutination absorption test (CAAT), and molecular typing. Common Leptospira serovars with their respective animal hosts were: Sokoine (cattle and rodents); Kenya (rodents and shrews); Mwogolo (rodents); Lora (rodents); Qunjian (rodent); serogroup Grippotyphosa (cattle); and an unknown serogroup from pigs. Inclusion of local serovars particularly serovar Sokoine in MAT revealed a 10-fold increase in leptospirosis prevalence in Tanzania from 1.9% to 16.9% in rodents and 0.26% to 10.75% in humans. This indicates that local serovars are useful for diagnosis of human and animal leptospirosis in Tanzania and other African countries. PMID:26624890

  13. The Type III Secretion System Effector SptP of Salmonella enterica Serovar Typhi

    PubMed Central

    Johnson, Rebecca; Byrne, Alexander; Berger, Cedric N.; Klemm, Elizabeth; Crepin, Valerie F.; Dougan, Gordon

    2016-01-01

    ABSTRACT Strains of the various Salmonella enterica serovars cause gastroenteritis or typhoid fever in humans, with virulence depending on the action of two type III secretion systems (Salmonella pathogenicity island 1 [SPI-1] and SPI-2). SptP is a Salmonella SPI-1 effector, involved in mediating recovery of the host cytoskeleton postinfection. SptP requires a chaperone, SicP, for stability and secretion. SptP has 94% identity between S. enterica serovar Typhimurium and S. Typhi; direct comparison of the protein sequences revealed that S. Typhi SptP has numerous amino acid changes within its chaperone-binding domain. Subsequent comparison of ΔsptP S. Typhi and S. Typhimurium strains demonstrated that, unlike SptP in S. Typhimurium, SptP in S. Typhi was not involved in invasion or cytoskeletal recovery postinfection. Investigation of whether the observed amino acid changes within SptP of S. Typhi affected its function revealed that S. Typhi SptP was unable to complement S. Typhimurium ΔsptP due to an absence of secretion. We further demonstrated that while S. Typhimurium SptP is stable intracellularly within S. Typhi, S. Typhi SptP is unstable, although stability could be recovered following replacement of the chaperone-binding domain with that of S. Typhimurium. Direct assessment of the strength of the interaction between SptP and SicP of both serovars via bacterial two-hybrid analysis demonstrated that S. Typhi SptP has a significantly weaker interaction with SicP than the equivalent proteins in S. Typhimurium. Taken together, our results suggest that changes within the chaperone-binding domain of SptP in S. Typhi hinder binding to its chaperone, resulting in instability, preventing translocation, and therefore restricting the intracellular activity of this effector. IMPORTANCE Studies investigating Salmonella pathogenesis typically rely on Salmonella Typhimurium, even though Salmonella Typhi causes the more severe disease in humans. As such, an understanding of

  14. Estimation of four land surface essential climate variables (albedo, LAI/FAPAR, and Fcover) from VIIRS data

    NASA Astrophysics Data System (ADS)

    Liang, Shunlin

    2016-07-01

    As the successor of MODIS, the Visible Infrared Imaging Radiometer Suite (VIIRS) from the Suomi National Polar-orbiting Partnership (S-NPP) and future Joint Polar Satellite System (JPSS) brings us into a new era of global daily Earth observations. VIIRS was designed to improve upon the capabilities of the operational AVHRR and provide observation continuity with MODIS. This presentation will describe the progress in estimating four Essential Climate Variables (ECV): shortwave albedo (Wang, et al., 2013; Zhou, et al., 2016), leaf area index (LAI) (Xiao et al., 2016), fraction of absorbed photosynthetically active radiation (FAPAR) (Xiao et al., 2016), and fractional vegetation coverage (Fcover) (Li, et al., 2016) from VIIRS data. The algorithms have been peer reviewed, and shortwave albedo has been operationally produced by NOAA and accessible to the scientific community. Li, Y., K. Jia, S. Liang, Z. Xiao, X. Wang, L. Yang, (2016), An operational algorithm for estimating fractional vegetation cover from VIIRS reflectance data based on general regression neural networks, Remote Sensing, revised Xiao, Z., S. Liang, T. Wang, and B. Jiang, (2016), Retrieval of Leaf Area Index and Fraction of Absorbed Photosynthetically Active Radiation from VIIRS Time Series Data, Remote Sensing, revised. Wang, D., S. Liang, T. He, and Y. Yu, (2013), Direct Estimation of Land Surface Albedo from VIIRS Data: Algorithm Improvement and Preliminary Validation, Journal of Geophysical Research, 118(22):12,577-12,586 Zhou, Y., D. Wang, S. Liang, Y. Yu, and T. He, (2016), Assessment of the Suomi NPP VIIRS Land Surface Albedo Data Using Station Measurements and High-Resolution Albedo Maps, Remote Sensing, in press.

  15. Immunization with truncated recombinant protein SpaC of Erysipelothrix rhusiopathiae strain 715 serovar 18 confers protective immunity against challenge with various serovars.

    PubMed

    To, Ho; Someno, Shuichi; Nagai, Shinya; Koyama, Tomohiro; Nagano, Tetsuji

    2010-12-01

    Previously, we showed that surface protective antigen (Spa) proteins of Erysipelothrix rhusiopathiae can be classified into three molecular species-SpaA, SpaB, and SpaC-and that SpaC is the most broadly cross-protective antigen among the three Spa proteins. In this study, we examined the ability of the α-helical domain, which comprises the N-terminal half of SpaC, to elicit cross-protective immunity in mice and pigs. Mice actively immunized with the full-length protein (rSpaC664) or the α-helical domain (rSpaC427), but not the C-terminal domain (rSpaC253), were protected against challenge with E. rhusiopathiae serovars 1a, 2, 6, 19, and 18 expressing heterologous (SpaA or SpaB) and homologous (SpaC) Spas. The α-helical domain seemed to provide better protection than rSpaC664, although the differences did not reach statistical significance. Similarly, mice passively immunized with rabbit anti-rSpaC664 or anti-rSpaC427 sera, but not anti-rSpaC253 serum, were protected from challenge with various serovars. Pigs immunized with SpaC427 also developed specific antibodies against Spa proteins and were protected from challenge with the highly virulent heterologous E. rhusiopathiae strain Fujisawa (serovar 1a). Taken together, these results demonstrate for the first time the striking protective efficacy of the α-helical domain-mediated immunization in both mice and pigs, thereby highlighting its utility as the most promising candidate for the development of a safe and effective vaccine against erysipelas.

  16. Chromosome-Directed PCR-Based Detection and Quantification of Bacillus cereus Group Members with Focus on B. thuringiensis Serovar israelensis Active against Nematoceran Larvae.

    PubMed

    Schneider, Salome; Hendriksen, Niels B; Melin, Petter; Lundström, Jan O; Sundh, Ingvar

    2015-08-01

    Bacillus thuringiensis serovar israelensis is a wide-spread soil bacterium affiliated with the B. cereus group (Bcg) and is widely used in biocontrol products applied against mosquito and black fly larvae. For monitoring and quantification of applied B. thuringiensis serovar israelensis and its effect on indigenous B. thuringiensis serovar israelensis and Bcg assemblages, efficient and reliable tools are essential. The abundance and properties of B. thuringiensis serovar israelensis strains in the environment traditionally have been investigated with cultivation-dependent techniques, which are hampered by low sensitivity and the morphological similarity between B. cereus and B. thuringiensis. Currently available PCR-based detection and quantification tools target markers located on plasmids. In this study, a new cultivation-independent PCR-based method for efficient and specific quantification of B. thuringiensis serovar israelensis and Bcg is presented, utilizing two sets of PCR primers targeting the bacterial chromosome. Sequence database searches and empirical tests performed on target and nontarget species, as well as on bulk soil DNA samples, demonstrated that this diagnostic tool is specific for B. thuringiensis serovar israelensis and Bcg. The method will be useful for comparisons of Bcg and B. thuringiensis serovar israelensis abundances in the same samples. Moreover, the effect of B. thuringiensis serovar israelensis-based insecticide application on the total Bcg assemblages, including indigenous populations, can be investigated. This type of information is valuable in risk assessment and policy making for use of B. thuringiensis serovar israelensis in the environment.

  17. Chromosome-Directed PCR-Based Detection and Quantification of Bacillus cereus Group Members with Focus on B. thuringiensis Serovar israelensis Active against Nematoceran Larvae

    PubMed Central

    Hendriksen, Niels B.; Melin, Petter; Lundström, Jan O.; Sundh, Ingvar

    2015-01-01

    Bacillus thuringiensis serovar israelensis is a wide-spread soil bacterium affiliated with the B. cereus group (Bcg) and is widely used in biocontrol products applied against mosquito and black fly larvae. For monitoring and quantification of applied B. thuringiensis serovar israelensis and its effect on indigenous B. thuringiensis serovar israelensis and Bcg assemblages, efficient and reliable tools are essential. The abundance and properties of B. thuringiensis serovar israelensis strains in the environment traditionally have been investigated with cultivation-dependent techniques, which are hampered by low sensitivity and the morphological similarity between B. cereus and B. thuringiensis. Currently available PCR-based detection and quantification tools target markers located on plasmids. In this study, a new cultivation-independent PCR-based method for efficient and specific quantification of B. thuringiensis serovar israelensis and Bcg is presented, utilizing two sets of PCR primers targeting the bacterial chromosome. Sequence database searches and empirical tests performed on target and nontarget species, as well as on bulk soil DNA samples, demonstrated that this diagnostic tool is specific for B. thuringiensis serovar israelensis and Bcg. The method will be useful for comparisons of Bcg and B. thuringiensis serovar israelensis abundances in the same samples. Moreover, the effect of B. thuringiensis serovar israelensis-based insecticide application on the total Bcg assemblages, including indigenous populations, can be investigated. This type of information is valuable in risk assessment and policy making for use of B. thuringiensis serovar israelensis in the environment. PMID:25979887

  18. Poultry as a possible source of non-typhoidal Salmonella enterica serovars in humans in Bangladesh.

    PubMed

    Barua, Himel; Biswas, Paritosh Kumar; Talukder, Kaisar Ali; Olsen, Katharina E P; Christensen, Jens Peter

    2014-01-31

    We investigated Salmonella enterica isolates from human clinical cases of gastroenteritis to determine the distribution of non-typhoidal Salmonella serovars in the human population, and compared them to isolates originating from poultry by serotyping, phage typing, plasmid profiling, pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) to evaluate the potential role of poultry in human non-typhoidal salmonellosis in Bangladesh. Nine different serovars were identified among the human isolates of which Salmonella Paratyphi B var Java (S. Java), S. Kentucky, S. Enteritidis, S. Virchow and S. Weltevreden also were commonly isolated from poultry. The poultry isolates belonging to S. Java, S. Kentucky and S. Enteritidis were indistinguishable from human isolates or genetically closely related, based on PFGE profiles and MLST. S. Kentucky clone ST198 and S. Java clone ST43 both well-known cause of human infections were also isolated from poultry.

  19. The Vi capsular polysaccharide enables Salmonella enterica serovar typhi to evade microbe-guided neutrophil chemotaxis.

    PubMed

    Wangdi, Tamding; Lee, Cheng-Yuk; Spees, Alanna M; Yu, Chenzhou; Kingsbury, Dawn D; Winter, Sebastian E; Hastey, Christine J; Wilson, R Paul; Heinrich, Volkmar; Bäumler, Andreas J

    2014-08-01

    Salmonella enterica serovar Typhi (S. Typhi) causes typhoid fever, a disseminated infection, while the closely related pathogen S. enterica serovar Typhimurium (S. Typhimurium) is associated with a localized gastroenteritis in humans. Here we investigated whether both pathogens differ in the chemotactic response they induce in neutrophils using a single-cell experimental approach. Surprisingly, neutrophils extended chemotactic pseudopodia toward Escherichia coli and S. Typhimurium, but not toward S. Typhi. Bacterial-guided chemotaxis was dependent on the presence of complement component 5a (C5a) and C5a receptor (C5aR). Deletion of S. Typhi capsule biosynthesis genes markedly enhanced the chemotactic response of neutrophils in vitro. Furthermore, deletion of capsule biosynthesis genes heightened the association of S. Typhi with neutrophils in vivo through a C5aR-dependent mechanism. Collectively, these data suggest that expression of the virulence-associated (Vi) capsular polysaccharide of S. Typhi obstructs bacterial-guided neutrophil chemotaxis.

  20. Salmonella enterica Serovar Typhimurium and Escherichia coli Contamination of Root and Leaf Vegetables Grown in Soils with Incorporated Bovine Manure

    PubMed Central

    Natvig, Erin E.; Ingham, Steven C.; Ingham, Barbara H.; Cooperband, Leslie R.; Roper, Teryl R.

    2002-01-01

    Bovine manure, with or without added Salmonella enterica serovar Typhimurium (three strains), was incorporated into silty clay loam (SCL) and loamy sand (LS) soil beds (53- by 114-cm surface area, 17.5 cm deep) and maintained in two controlled-environment chambers. The S. enterica serovar Typhimurium inoculum was 4 to 5 log CFU/g in manure-fertilized soil. The conditions in the two environmental chambers, each containing inoculated and uninoculated beds of manure-fertilized soil, simulated daily average Madison, Wis., weather conditions (hourly temperatures, rainfall, daylight, and humidity) for a 1 March or a 1 June manure application and subsequent vegetable growing seasons ending 9 August or 28 September, respectively. Core soil samples were taken biweekly from both inoculated and uninoculated soil beds in each chamber. Radishes, arugula, and carrots were planted in soil beds, thinned, and harvested. Soils, thinned vegetables, and harvested vegetables were analyzed for S. enterica serovar Typhimurium and Escherichia coli (indigenous in manure). After the 1 March manure application, S. enterica serovar Typhimurium was detected at low levels in both soils on 31 May, but not on vegetables planted 1 May and harvested 12 July from either soil. After the 1 June manure application, S. enterica serovar Typhimurium was detected in SCL soil on 7 September and on radishes and arugula planted in SCL soil on 15 August and harvested on 27 September. In LS soil, S. enterica serovar Typhimurium died at a similar rate (P ≥ 0.05) after the 1 June manure application and was less often detected on arugula and radishes harvested from this soil compared to the SCL soil. Pathogen levels on vegetables were decreased by washing. Manure application in cool (daily average maximum temperature of <10°C) spring conditions is recommended to ensure that harvested vegetables are not contaminated with S. enterica serovar Typhimurium. Manure application under warmer (daily average maximum

  1. Tragedy at My Lai

    DTIC Science & Technology

    2010-01-01

    conduct such savage acts of cruelty and murder? Throughout the course of research three contributing elements stood out above all others. Those were...able to view the Vietnamese through a more familiar human lens and less as animals or sub-humans. If the VC’s tactics had taken a more

  2. Detection of Salmonella serovars from clinical samples by enrichment broth cultivation-PCR procedure.

    PubMed Central

    Stone, G G; Oberst, R D; Hays, M P; McVey, S; Chengappa, M M

    1994-01-01

    To overcome problems associated with application of PCR to clinical samples, we have combined a short cultivation procedure with a Salmonella-specific PCR-hybridization assay to specifically identify Salmonella serovars from clinical samples of various animal species. The technique was investigated by using fecal samples seeded with known numbers of Salmonella organisms and cultivated for different lengths of time in assorted selective and nonselective enrichment media. The ability of PCR to amplify a Salmonella-specific DNA product (457-bp sequence covering the Salmonella invE and invA genes) was examined in Southern hybridizations with an internal oligonucleotide probe. Forty-seven Salmonella isolates representing 32 serovars were evaluated, and all Salmonella isolates resulted in a 457-bp product that hybridized with the oligonucleotide probe, whereas no hybridizations were evident with 53 non-Salmonella organisms. The assay detected as few as 9 CFU of Salmonella organisms in pure culture and as little as 300 fg of purified chromosomal DNA. Rappaport-Vassiliadis and tetrathionate broths were inhibitory to PCR, whereas brain heart infusion and selenite-cystine broths were not. The PCR-hybridization assay coupled with a brain heart infusion enrichment culture incubated for 2 h detected as few as 80 CFU of Salmonella organisms in seeded feces. We have successfully identified Salmonella serovars in clinical samples from swine, horses, and cattle more rapidly than with conventional culture techniques. The sensitivity and specificity of this assay were both 100% compared with culture results. These results indicate that a combined cultivation-PCR-hybridization assay could be applicable and advantageous in the rapid identification of Salmonella serovars in routine diagnostic situations. Images PMID:7929768

  3. Intermediate Susceptibility to Ciprofloxacin among Salmonella enterica Serovar Typhi Isolates in Lima, Peru

    PubMed Central

    Lejon, Veerle; Horna, Gertrudis; Astocondor, Lizeth; Vanhoof, Raymond; Bertrand, Sophie; Jacobs, Jan

    2014-01-01

    Thirty-three Salmonella enterica serovar Typhi blood isolates from Lima, Peru (2008 to 2012), were fully susceptible to trimethoprim-sulfamethoxazole, chloramphenicol, ceftriaxone, and tetracycline; 8/33 (24.2%) showed intermediate susceptibility to ciprofloxacin carrying mutations in the quinolone resistance-determining region of the gyrA gene (Ser83-Phe and Asp87-Asn) and in the gyrB gene (Ser464-Phe). PMID:24371234

  4. Draft Genome Sequence of the Tumor-Targeting Salmonella enterica Serovar Typhimurium Strain SL7207

    PubMed Central

    Johnson, Síle A.; Ormsby, Michael J.

    2017-01-01

    ABSTRACT Salmonella enterica serovar Typhimurium strain SL7207 is a genetically modified derivative of strain SL1344, which preferentially accumulates in tumors and can be used as a vehicle for tissue-specific gene delivery in vivo. Here, we report the draft genome sequence of SL7207, confirming a purported aroA deletion and four single-nucleotide polymorphisms compared to SL1344. PMID:28153911

  5. Induction and Resuscitation of Viable but Nonculturable Salmonella enterica Serovar Typhimurium DT104†

    PubMed Central

    Gupte, A. R.; de Rezende, C. L. E.; Joseph, S. W.

    2003-01-01

    Salmonella enterica serovar Typhimurium DT104 11601was tested for its ability to maintain viability in minimal, chemically defined solutions. Periodic monitoring of growth and survival in microcosms of different ion concentrations, maintained at various temperatures, showed a gradual decline in culturable organisms (∼235 days) at 5°C. Organisms maintained at a higher temperature (21°C) showed continuous, equivalent CFU per milliliter (∼106) up to 400 days after inoculation. Fluorescence microscopy with Baclight revealed that nonculturable cells were actually viable, while observations with scanning electron microscopy showed that the cells had retained their structural integrity. Temperature upshift (56°C ± 0.5, 15 s) of the nonculturable organisms (5°C) in Trypticase soy broth followed by immediate inoculation onto Trypticase soy agar (TSA) gave evidence of resuscitation. Interestingly, S. enterica serovar Typhimurium DT104 from the microcosms at either 5°C (1 to 200 days) or 21°C (1 to 250 days) did not show enhanced growth after intermittent inoculation onto catalase-supplemented TSA. Furthermore, cells from 21°C microcosms exposed to oxidative and osmotic stress showed greater resistance to stresses over increasing times of exposure than did recently grown cells. It is possible that the exceptional survivability and resilience of this particular strain may in part reflect the growing importance of this multidrug-resistant organism, in general, as a cause of intestinal disease in humans. The fact that S. enterica serovar Typhimurium DT104 11601 is capable of modifying its physiological characteristics, including entry into and recovery from the viable but nonculturable state, suggests the overall possibility that S. enterica serovar Typhimurium DT104 may be able to respond uniquely to various adverse environmental conditions. PMID:14602627

  6. Antibiotic resistance and diversity of Salmonella enterica serovars associated with broiler chickens.

    PubMed

    Diarra, Moussa Sory; Delaquis, Pascal; Rempel, Heidi; Bach, Susan; Harlton, Colleen; Aslam, Mueen; Pritchard, Jane; Topp, Edward

    2014-01-01

    The objective of this study was to analyze the antibiotic resistance phenotype and genotype of Salmonella isolated from broiler production facilities. A total of 193 Salmonella isolates recovered from commercial farms in British Columbia, Canada, were evaluated. Susceptibility to antibiotics was determined with the Sensititre system. Virulence and antibiotic resistance genes were detected by PCR assay. Genetic diversity was determined by pulse-field gel electrophoresis (PFGE) typing. Seventeen serovars of Salmonella were identified. The most prevalent Salmonella serovars were Kentucky (29.0% of isolates), Typhimurium (23.8%), Enteritidis (13.5%), and Hadar (11.9%); serovars Heidelberg, Brandenburg, and Thompson were identified in 7.7, 4.1, and 3.6% of isolates, respectively. More than 43% of the isolates were simultaneously resistant to ampicillin, amoxicillin-clavulanic acid, ceftiofur, cefoxitim, and ceftriaxone. This β-lactam resistance pattern was observed in 33 (58.9%) of the Salmonella Kentucky isolates; 2 of these isolates were also resistant to chloramphenicol, streptomycin, sulfisoxazole, and tetracycline. Genes associated with resistance to aminoglycosides (aadA1, aadA2, and strA), β-lactams (blaCMY-2, blaSHV, and blaTEM), tetracycline (tetA and tetB), and sulfonamide (sul1) were detected among corresponding resistant isolates. The invasin gene (invA) and the Salmonella plasmid virulence gene (spvC) were found in 97.9 and 25.9% of the isolates, respectively, with 33 (71.7%) of the 46 Salmonella Typhimurium isolates and 17 (65.4%) of the 26 Salmonella Enteritidis isolates carrying both invA and spvC. PGFE typing revealed that the antibiotic-resistant serovars were genetically diverse. These data confirm that broiler chickens can be colonized by genetically diverse antibiotic-resistant Salmonella isolates harboring virulence determinants. The presence of such strains is highly relevant to food safety and public health.

  7. Differences in attachment of Salmonella enterica serovars to cabbage and lettuce leaves.

    PubMed

    Patel, Jitendra; Sharma, Manan

    2010-04-30

    This study investigated the ability of five Salmonella enterica serovars to attach to and colonize intact and cut lettuce (Iceberg, Romaine) and cabbage surfaces. Biofilm formation and attachment of Salmonella serovars to intact and cut leaves were determined. Populations of loosely and strongly attached Salmonella were obtained to calculate the attachment strength (S(R)). Biofilm formation, as determined by microtiter plate assay, varied with strain and growth medium used. Salmonella Tennessee and S. Thompson produced stronger biofilms compared to S. Newport, S. Negev, and S. Braenderup. Biofilm formation was also stronger when Salmonella spp. were grown in diluted TSB (1:10). S. Tennessee, which produced strong biofilms, attached to produce surfaces at significantly higher numbers than the populations of S. Negev. Overall, S. Tennessee displayed more biofilm formation in vitro and attached more strongly to lettuce than other serovars. All Salmonella serovars attached rapidly on intact and cut produce surfaces. Salmonella spp. attached to Romaine lettuce at significantly higher numbers than those attached to Iceberg lettuce or cabbage. Salmonella attached preferentially to cut surface of all produce; however, the difference between Salmonella populations attached to intact and cut surfaces was similar (P>0.05). Salmonella attachment to both intact and cut produce surfaces increased with time. The overall attachment strength of Salmonella was significantly lower on cabbage (0.12) followed by Iceberg (0.23) and Romaine lettuce (0.34). Cabbage, intact or cut, did not support attachment of Salmonella as well as Romaine lettuce. Understanding the attachment mechanisms of Salmonella to produce may be useful in developing new intervention strategies to prevent produce outbreaks.

  8. Salmonella contamination, serovars and antimicrobial resistance profiles of cattle slaughtered in South Africa.

    PubMed

    Madoroba, Evelyn; Kapeta, Daniel; Gelaw, Awoke K

    2016-05-26

    Antimicrobial resistant Salmonella are among the leading causes of foodborne infections. Our aim was to determine Salmonella contamination during cattle slaughter in South African rural abattoirs (n = 23) and environmental samples. Furthermore, antimicrobial resistance patterns of the Salmonella isolates were determined. Samples of cattle faeces (n = 400), carcass sponges (n = 100), intestinal contents (n = 62), hides (n = 67), and water from the abattoirs (n = 75) were investigated for Salmonella species using microbiological techniques and species-specific polymerase chain reaction targeting the invA gene. In total 92 Salmonella species isolates were recovered. The Salmonella mean frequency of occurrence on hides, carcasses, and intestinal contents was 35.37% (n = 81). Eleven faecal samples (2.75%) tested positive for Salmonella. The predominant serovar was Salmonella Enteritidis. Diverse serovars that were identified on carcasses were not necessarily found on the hides and intestinal contents. The inconsistent occurrence of the diverse Salmonella serovars on hides, carcasses, and intestinal contents implies that in addition to carriage on hides and in intestinal contents, other external factors also play an important role regarding carcass contamination. The 92 Salmonella were serotyped and tested for susceptibility towards the following antimicrobials: ampicillin, cefotaxime, enrofloxacin, kanamycin, and oxytetracycline using the disk diffusion method. Most Salmonella (n = 66; 71.7%) isolates were resistant to at least one antimicrobial with highest resistance observed towards oxytetracycline (51.90%), which highlights the need for strict hygiene during slaughter and prudent antimicrobial use during animal production. In conclusion, cattle slaughtered in South African rural abattoirs harbour diverse Salmonella serovars that are resistant to antimicrobials, which could be a public health risk. The findings should assist policymakers with improving implementation

  9. Salmonella contamination, serovars and antimicrobial resistance profiles of cattle slaughtered in South Africa.

    PubMed

    Madoroba, Evelyn; Kapeta, Daniel; Gelaw, Awoke K

    2016-05-26

    Antimicrobial resistant Salmonella are among the leading causes of foodborne infections. Our aim was to determine Salmonella contamination during cattle slaughter in South African rural abattoirs (n = 23) and environmental samples. Furthermore, antimicrobial resistance patterns of the Salmonella isolates were determined. Samples of cattle faeces (n = 400), carcass sponges (n = 100), intestinal contents (n = 62), hides (n = 67), and water from the abattoirs (n = 75) were investigated for Salmonella species using microbiological techniques and species-specific polymerase chain reaction targeting the invA gene. In total 92 Salmonella species isolates were recovered. The Salmonella mean frequency of occurrence on hides, carcasses, and intestinal contents was 35.37% (n = 81). Eleven faecal samples (2.75%) tested positive for Salmonella. The predominant serovar was Salmonella Enteritidis. Diverse serovars that were identified on carcasses were not necessarily found on the hides and intestinal contents. The inconsistent occurrence of the diverse Salmonella serovars on hides, carcasses, and intestinal contents implies that in addition to carriage on hides and in intestinal contents, other external factors also play an important role regarding carcass contamination. The 92 Salmonella were serotyped and tested for susceptibility towards the following antimicrobials: ampicillin, cefotaxime, enrofloxacin, kanamycin, and oxytetracycline using the disk diffusion method. Most Salmonella (n = 66; 71.7%) isolates were resistant to at least one antimicrobial with highest resistance observed towards oxytetracycline (51.90%), which highlights the need for strict hygiene during slaughter and prudent antimicrobial use during animal production. In conclusion, cattle slaughtered in South African rural abattoirs harbour diverse Salmonella serovars that are resistant to antimicrobials, which could be a public health risk. The findings should assist policymakers with improving implementation

  10. mcr-1−Harboring Salmonella enterica Serovar Typhimurium Sequence Type 34 in Pigs, China

    PubMed Central

    Yi, Linxian; Wang, Jing; Gao, Yanling; Liu, Yiyun; Doi, Yohei; Wu, Renjie; Zeng, Zhenling; Liang, Zisen

    2017-01-01

    We detected the mcr-1 gene in 21 (14.8%) Salmonella isolates from pigs at slaughter; 19 were serovar Typhimurium sequence type 34. The gene was located on IncHI2-like plasmids that also harbored IncF replicons and lacked a conjugative transfer region. These findings highlight the need to prevent further spread of colistin resistance in animals and humans. PMID:28098547

  11. Salmonella enterica Serovar Virchow with CTX-M-Like β-Lactamase in Spain

    PubMed Central

    Simarro, Encarna; Navarro, Ferrán; Ruiz, Joaquín; Miró, Elisenda; Gómez, Joaquín; Mirelis, Beatriz

    2000-01-01

    Four Salmonella enterica serovar Virchow strains resistant to broad-spectrum cephalosporins were isolated from patients with gastroenteritis in 1997 and 1998 in Murcia and Barcelona, Spain. The isolates expressed a β-lactamase with a pI of about 8 and a positive PCR when specific primers for CTX-M-9 were used. These results suggest the presence of a CTX-M-9 β-lactamase in these strains. PMID:11101623

  12. Anti-infective mechanisms induced by a probiotic Lactobacillus strain against Salmonella enterica serovar Typhimurium infection.

    PubMed

    de LeBlanc, Alejandra de Moreno; Castillo, Natalia A; Perdigon, Gabriela

    2010-04-15

    The prevention of pathogen infections is one of the most extensively studied effects of probiotics. L. casei CRL 431 is a probiotic bacterium and its effects on the gut immune cells have been extensively studied. The aim of the present study was to determine, using a mouse model, the preventive and therapeutic effect of L. casei CRL 431 to achieve protection against Salmonella enteritidis serovar Typhimurium infection. In both previous and continuous (previous and post-infection) probiotic administration, the mechanisms induced by this lactic acid bacteria on the first line of intestinal defense (non-specific barrier and the innate immune cells associated to the gut), as a way to understand some of the mechanisms involved in the protection against Salmonella enteritidis serovar Typhimurium, were analyzed. The results obtained demonstrated that 7 days L. casei CRL 431 administration before infection decreased the severity of the infection with Salmonella enteritidis serovar Typhimurium, demonstrating that the continuous administration (even after infection) had the best effect. This continuous administration diminished the counts of the pathogen in the intestine as well as its spread outside this organ. Several mechanisms and cells are involved in this protective effect against Salmonella enteritidis serovar Typhimurium. L. casei CRL 431 acted on cells of the innate and adaptive immune response. The probiotic administration decreased the neutrophil infiltration with the consequent diminution of intestinal inflammation; activated the macrophage phagocytic activity in different sites such as Peyer's patches, spleen and peritoneum; and increased the number of IgA+cells in the lamina propria of the small intestine which was correlated with increased release of s-IgA specific against the pathogen in the intestinal fluids. The mechanism of the inhibition of cellular apoptosis was not involved.

  13. Infections by Leptospira interrogans, Seoul virus, and Bartonella spp. among Norway rats (Rattus norvegicus) from the urban slum environment in Brazil.

    PubMed

    Costa, Federico; Porter, Fleur Helena; Rodrigues, Gorete; Farias, Helena; de Faria, Marcus Tucunduva; Wunder, Elsio A; Osikowicz, Lynn M; Kosoy, Michael Y; Reis, Mitermayer Galvão; Ko, Albert I; Childs, James E

    2014-01-01

    Norway rats (Rattus norvegicus) are reservoir hosts for zoonotic pathogens that cause significant morbidity and mortality in humans. Studies evaluating the prevalence of zoonotic pathogens in tropical Norway rat populations are rare, and data on co-infection with multiple pathogens are nonexistent. Herein, we describe the prevalence of leptospiral carriage, Seoul virus (SEOV), and Bartonella spp. infection independently, in addition to the rates of co-infection among urban, slum-dwelling Norway rats in Salvador, Brazil, trapped during the rainy season from June to August of 2010. These data were complemented with previously unpublished Leptospira and SEOV prevalence information collected in 1998. Immunofluorescence staining of kidney impressions was used to identify Leptospira interrogans in 2010, whereas isolation was used in 1998, and western blotting was used to detect SEOV antibodies in 2010, whereas enzyme-linked immunosorbent assay (ELISA) was used in 1998: in 2010, Bartonella spp. were isolated from a subsample of rats. The most common pathogen in both years was Leptospira spp. (83%, n=142 in 1998, 63%, n=84 in 2010). SEOV was detected in 18% of individuals in both 1998 and 2010 (n=78 in 1998; n=73 in 2010), and two species of Bartonella were isolated from 5 of 26 rats (19%) tested in 2010. The prevalence of all agents increased significantly with rat mass/age. Acquisition of Leptospira spp. occurred at a younger mass/age than SEOV and Bartonella spp. infection, suggesting differences in the transmission dynamics of these pathogens. These data indicate that Norway rats in Salvador serve as reservoir hosts for all three of these zoonotic pathogens and that the high prevalence of leptospiral carriage in Salvador rats poses a high degree of risk to human health.

  14. Infections by Leptospira interrogans, Seoul Virus, and Bartonella spp. Among Norway Rats (Rattus norvegicus) from the Urban Slum Environment in Brazil

    PubMed Central

    Porter, Fleur Helena; Rodrigues, Gorete; Farias, Helena; de Faria, Marcus Tucunduva; Wunder, Elsio A.; Osikowicz, Lynn M.; Kosoy, Michael Y.; Reis, Mitermayer Galvão; Ko, Albert I.; Childs, James E.

    2014-01-01

    Abstract Norway rats (Rattus norvegicus) are reservoir hosts for zoonotic pathogens that cause significant morbidity and mortality in humans. Studies evaluating the prevalence of zoonotic pathogens in tropical Norway rat populations are rare, and data on co-infection with multiple pathogens are nonexistent. Herein, we describe the prevalence of leptospiral carriage, Seoul virus (SEOV), and Bartonella spp. infection independently, in addition to the rates of co-infection among urban, slum-dwelling Norway rats in Salvador, Brazil, trapped during the rainy season from June to August of 2010. These data were complemented with previously unpublished Leptospira and SEOV prevalence information collected in 1998. Immunofluorescence staining of kidney impressions was used to identify Leptospira interrogans in 2010, whereas isolation was used in 1998, and western blotting was used to detect SEOV antibodies in 2010, whereas enzyme-linked immunosorbent assay (ELISA) was used in 1998: in 2010, Bartonella spp. were isolated from a subsample of rats. The most common pathogen in both years was Leptospira spp. (83%, n=142 in 1998, 63%, n=84 in 2010). SEOV was detected in 18% of individuals in both 1998 and 2010 (n=78 in 1998; n=73 in 2010), and two species of Bartonella were isolated from 5 of 26 rats (19%) tested in 2010. The prevalence of all agents increased significantly with rat mass/age. Acquisition of Leptospira spp. occurred at a younger mass/age than SEOV and Bartonella spp. infection, suggesting differences in the transmission dynamics of these pathogens. These data indicate that Norway rats in Salvador serve as reservoir hosts for all three of these zoonotic pathogens and that the high prevalence of leptospiral carriage in Salvador rats poses a high degree of risk to human health. PMID:24359425

  15. Characterization of Leptospira santarosai Serogroup Grippotyphosa Serovar Bananal Isolated from Capybara ( Hydrochaeris hydrochaeris ) in Brazil.

    PubMed

    Moreno, Luisa Z; Miraglia, Fabiana; Marvulo, Maria F V; Silva, Jean C R; Paula, Catia D; Costa, Barbara L P; Morais, Zenaide M; Ferreira, Fernando; Neto, José S Ferreira; Dellagostin, Odir A; Hartskeerl, Rudy A; Vasconcellos, Silvio A; Moreno, Andrea M

    2016-07-01

    Leptospirosis is a widespread zoonosis caused by bacteria of the genus Leptospira. Rodents appear to be the most important reservoirs of infection. They contaminate the environment and food and can transmit the pathogen when they are consumed by carnivores. Capybara ( Hydrochaeris hydrochaeris ) are efficient reservoirs of Leptospira, and because they are in close contact with farm animals and are found in semiurban areas, they represent a risk to public health. We isolated five Leptospira strains from capybara kidneys in Sao Paulo State, Brazil, in 2001 and typed them using serologic and molecular techniques. These strains include the Leptospira santarosai serogroup Grippotyphosa serovar Bananal. Pulsed field gel electrophoresis resulted in a unique pattern distinct from the reference strains, and the isolates clustered with greater than 85% similarity. The isolates also presented higher growth rates than other Leptospira serovars, with high minimal inhibitory concentration values for most of the tested antibiotics, with the exception of penicillin and ampicillin. This isolation and characterization of the L. santarosai serogroup Grippotyphosa serovar Bananal from capybara, highlights the importance of wild and sinantropic rodents as carriers of pathogenic leptospires.

  16. Prevalence and characterization of Salmonella serovars isolated from oysters served raw in restaurants.

    PubMed

    Brillhart, Crystal D; Joens, Lynn A

    2011-06-01

    To determine if Salmonella-contaminated oysters are reaching consumer tables, a survey of raw oysters served in eight Tucson restaurants was performed from October 2007 to September 2008. Salmonella spp. were isolated during 7 of the 8 months surveyed and were present in 1.2% of 2,281 oysters tested. This observed prevalence is lower than that seen in a previous study in which U.S. market oysters were purchased from producers at bays where oysters are harvested. To test whether the process of refrigerating oysters in restaurants for several days reduces Salmonella levels, oysters were artificially infected with Salmonella and kept at 4°C for up to 13 days. Direct plate counts of oyster homogenate showed that Salmonella levels within oysters did not decrease during refrigeration. Six different serovars of Salmonella enterica were found in the restaurant oysters, indicating multiple incidences of Salmonella contamination of U.S. oyster stocks. Of the 28 contaminated oysters, 12 (43%) contained a strain of S. enterica serovar Newport that matched by pulsed-field gel electrophoresis a serovar Newport strain seen predominantly in the study of bay oysters performed in 2002. The repeated occurrence of this strain in oyster surveys is concerning, since the strain was resistant to seven antimicrobials tested and thus presents a possible health risk to consumers of raw oysters.

  17. The flagellar regulator TviA reduces pyroptosis by Salmonella enterica serovar Typhi.

    PubMed

    Winter, Sebastian E; Winter, Maria G; Atluri, Vidya; Poon, Victor; Romão, Everton L; Tsolis, Renée M; Bäumler, Andreas J

    2015-04-01

    To discern virulent from innocuous microbes, the innate immune system senses events associated with bacterial access to immunoprivileged sites such as the host cell cytosol. One such pathway is triggered by the cytosolic delivery of flagellin, the major subunit of the flagellum, by bacterial secretion systems. This leads to inflammasome activation and subsequent proinflammatory cell death (pyroptosis) of the infected phagocyte. In this study, we demonstrate that the causative agent of typhoid fever, Salmonella enterica serovar Typhi, can partially subvert this critical innate immune recognition event. The transcriptional regulator TviA, which is absent from Salmonella serovars associated with human gastroenteritis, repressed the expression of flagellin during infection of human macrophage-like (THP-1) cells. This mechanism allowed S. Typhi to dampen inflammasome activation, leading to reduced interleukin-1β (IL-1β) secretion and diminished cell death. Likewise, the introduction of the tviA gene in nontyphoidal Salmonella enterica serovar Typhimurium reduced flagellin-induced pyroptosis. These data suggest that gene regulation of virulence factors enables S. Typhi to evade innate immune recognition by concealing a pathogen-induced process from being sensed by the inflammasome.

  18. Salmonella DNA Adenine Methylase Mutants Elicit Protective Immune Responses to Homologous and Heterologous Serovars in Chickens

    PubMed Central

    Dueger, E. L.; House, J. K.; Heithoff, D. M.; Mahan, M. J.

    2001-01-01

    Salmonella DNA adenine methylase (Dam) mutants that lack or overproduce Dam are highly attenuated for virulence in mice and confer protection against murine typhoid fever. To determine whether vaccines based on Dam are efficacious in poultry, a Salmonella Dam− vaccine was evaluated in the protection of chicken broilers against oral challenge with homologous and heterologous Salmonella serovars. A Salmonella enterica serovar Typhimurium Dam− vaccine strain was attenuated for virulence in day-of-hatch chicks more than 100,000-fold. Vaccination of chicks elicited cross-protective immune responses, as evidenced by reduced colonization (10- to 10,000-fold) of the gastrointestinal tract (ileum, cecum, and feces) and visceral organs (bursa and spleen) after challenge with homologous (Typhimurium F98) and heterologous (Enteritidis 4973 and S. enterica O6,14,24: e,h-monophasic) Salmonella serovars that are implicated in Salmonella infection of poultry. The protection conferred was observed for the organ or the maximum CFU/tissue/bird as a unit of analysis, suggesting that Dam mutant strains may serve as the basis for the development of efficacious poultry vaccines for the containment of Salmonella. PMID:11705984

  19. Characterization of the ELPhiS prophage from Salmonella enterica serovar Enteritidis strain LK5.

    PubMed

    Hanna, L Farris; Matthews, T David; Dinsdale, Elizabeth A; Hasty, David; Edwards, Robert A

    2012-03-01

    Phages are a primary driving force behind the evolution of bacterial pathogens by transferring a variety of virulence genes into their hosts. Similar to other bacterial genomes, the Salmonella enterica serovar Enteritidis LK5 genome contains several regions that are homologous to phages. Although genomic analysis demonstrated the presence of prophages, it was unable to confirm which phage elements within the genome were viable. Genetic markers were used to tag one of the prophages in the genome to allow monitoring of phage induction. Commonly used laboratory strains of Salmonella were resistant to phage infection, and therefore a rapid screen was developed to identify susceptible hosts. This approach showed that a genetically tagged prophage, ELPhiS (Enteritidis lysogenic phage S), was capable of infecting Salmonella serovars that are diverse in host range and virulence and has the potential to laterally transfer genes between these serovars via lysogenic conversion. The rapid screen approach is adaptable to any system with a large collection of isolates and may be used to test the viability of prophages found by sequencing the genomes of various bacterial pathogens.

  20. Temperature and Oxygen Dependent Metabolite Utilization by Salmonella enterica Serovars Derby and Mbandaka

    PubMed Central

    Hayward, Matthew R.; AbuOun, Manal; Woodward, Martin J.; Jansen, Vincent A. A.

    2015-01-01

    Salmonella enterica is a zoonotic pathogen of clinical and veterinary significance, with over 2500 serovars. In previous work we compared two serovars displaying host associations inferred from isolation statistics. Here, to validate genome sequence data and to expand on the role of environmental metabolite constitution in host range determination we use a phenotypic microarray approach to assess the ability of these serovars to metabolise ~500 substrates at 25°C with oxygen (aerobic conditions) to represent the ex vivo environment and at 37°C with and without oxygen (aerobic/anaerobic conditions) to represent the in vivo environment. A total of 26 substrates elicited a significant difference in the rate of metabolism of which only one, D-galactonic acid-g-lactone, could be explained by the presence (S. Mbandaka) or the absence (S. Derby) of metabolic genes. We find that S. Mbandaka respires more efficiently at ambient temperatures and under aerobic conditions on 18 substrates including: glucosominic acid, saccharic acid, trehalose, fumaric acid, maltotriose, N-acetyl-D-glucosamine, N-acetyl-beta-D-mannosamine, fucose, L-serine and dihydroxy-acetone; whereas S. Derby is more metabolically competent anaerobically at 37°C for dipeptides, glutamine-glutamine, alanine-lysine, asparagine-glutamine and nitrogen sources glycine and nitrite. We conclude that the specific phenotype cannot be reliably predicted from the presence of metabolic genes directly relating to the metabolic pathways under study. PMID:25798944

  1. The inositol phosphatase SHIP controls Salmonella enterica serovar Typhimurium infection in vivo.

    PubMed

    Bishop, Jennifer L; Sly, Laura M; Krystal, Gerald; Finlay, B Brett

    2008-07-01

    The SH2 domain-containing inositol 5'-phosphatase, SHIP, negatively regulates various hematopoietic cell functions and is critical for maintaining immune homeostasis. However, whether SHIP plays a role in controlling bacterial infections in vivo remains unknown. Salmonella enterica causes human salmonellosis, a disease that ranges in severity from mild gastroenteritis to severe systemic illness, resulting in significant morbidity and mortality worldwide. The susceptibility of ship(+/+) and ship(-/-) mice and bone marrow-derived macrophages to S. enterica serovar Typhimurium infection was compared. ship(-/-) mice displayed an increased susceptibility to both oral and intraperitoneal serovar Typhimurium infection and had significantly higher bacterial loads in intestinal and systemic sites than ship(+/+) mice, indicating a role for SHIP in the gut-associated and systemic pathogenesis of serovar Typhimurium in vivo. Cytokine analysis of serum from orally infected mice showed that ship(-/-) mice produce lower levels of Th1 cytokines than do ship(+/+) animals at 2 days postinfection, and in vitro analysis of supernatants taken from infected bone marrow-derived macrophages derived to mimic the in vivo ship(-/-) alternatively activated (M2) macrophage phenotype correlated with these data. M2 macrophages were the predominant population in vivo in both oral and intraperitoneal infections, since tissue macrophages within the small intestine and peritoneal macrophages from ship(-/-) mice showed elevated levels of the M2 macrophage markers Ym1 and Arginase 1 compared to ship(+/+) cells. Based on these data, we propose that M2 macrophage skewing in ship(-/-) mice contributes to ineffective clearance of Salmonella in vivo.

  2. Serovars of Salmonella isolated from Danish turkeys between 1995 and 2000 and their antimicrobial resistance.

    PubMed

    Pedersen, K; Hansen, H C; Jørgensen, J C; Borck, B

    2002-04-13

    The prevalence of Salmonella serovars and their antimicrobial resistance patterns were investigated among Danish turkeys between 1995 and 2000, by sampling the flocks approximately 14 days before they were slaughtered. Within the flocks, the prevalence of salmonella varied from 7.1 per cent to 25 per cent, and 24 different serovars were detected. The five most prevalent, which accounted for 58.5 per cent of the isolates were Salmonella Heidelberg (16.2 per cent of the isolates), Salmonella Agona (15.8 per cent), Salmonella Derby (12.4 per cent), Salmonella Muenster (7.3 per cent) and Salmonella Anatum (6.8 per cent). In addition, a few rough isolates and isolates belonging to the antigenically incomplete formulae 6,7:-:- and 4,12:b:- were found. The level of antimicrobial resistance was low; the highest resistance was recorded to ampicillin (13.7 per cent) and streptomycin (9.0 per cent) followed by tetracycline (8.5 per cent), sulphonamides (7.7 per cent) and spectinomycin (4.7 per cent). Resistance to quinolones was very low: four isolates were resistant to nalidixic acid, and only one was resistant to enrofloxacin. No resistance was recorded to colistin, apramycin, ceftiofur, florfenicol, or amoxycillin with clavulanic acid. Only 24 isolates were resistant to two or more compounds in various combinations of up to six compounds; one Salmonella Havana isolate was resistant to six compounds. Six isolates were serovar Typhimurium, but none of them belonged to phage type DT104.

  3. Shoot Injury Increases the Level of Persistence of Salmonella enterica Serovar Sofia and Listeria innocua on Cos Lettuce and of Salmonella enterica Serovar Sofia on Chive.

    PubMed

    Harapas, Dean; Premier, Robert; Tomkins, Bruce; Hepworth, Graham; Ajlouni, Said

    2015-12-01

    Minor shoot injury significantly (P < 0.05) increased the level at which Salmonella enterica serovar Sofia persisted on cos lettuce in the greenhouse. Initial mean counts of the Salmonella on the injured and uninjured cos lettuce were on the order of 6 log CFU/g. After 3 days, the mean count decreased to 4.8 log CFU/g on the injured plants compared with the significantly (P < 0.05) smaller count of 3.4 log CFU/g on the uninjured plants. By the end of the 3-week experiment, the count from the injured plants was 2.9 log CFU/g compared with a count of below the level of detection from the uninjured plants. A similar pattern of bacterial persistence was observed on injured versus uninjured plants by using Listeria innocua on cos lettuce and S. enterica serovar Sofia on chive. The findings reaffirm earlier results with Escherichia coli and increase the impetus to avoid shoot injury during the production of cos lettuce and chive, if bacteria of food safety concern are present.

  4. Investigation on predominant Leptospira serovars and its distribution in humans and livestock in Thailand, 2010-2015

    PubMed Central

    Chadsuthi, Sudarat; Bicout, Dominique J.; Wiratsudakul, Anuwat; Suwancharoen, Duangjai; Petkanchanapong, Wimol; Modchang, Charin; Triampo, Wannapong; Ratanakorn, Parntep; Chalvet-Monfray, Karine

    2017-01-01

    Background Leptospirosis is a worldwide zoonotic bacterial disease caused by infection with leptospires. Leptospirosis in humans and livestock is an endemic and epidemic disease in Thailand. Livestock may act as reservoirs for leptospires and source for human infection. Methodology/Principal findings Data on leptospirosis infection in humans and livestock (Buffaloes, Cattle, and Pigs) species during 2010 to 2015 were analyzed. Serum samples were examined using Microscopic Agglutination Test (MAT) to identify antibodies against Leptospira serovars using a cut-off titer ≥ 1:100. The seroprevalence was 23.7% in humans, 24.8% in buffaloes, 28.1% in cattle, and 11.3% in pigs. Region specific prevalence among humans and livestock was found in a wide range. The most predominant serovars were Shermani, followed by Bratislava, Panama, and Sejroe in human, Shermani, Ranarum, and Tarassovi in buffaloes, and Shermani and Ranarum in cattle and pigs. Equally highest MAT titers against multiple serovars per one sample were found mainly in buffaloes and cattle showing equally titers against Ranarum and Shermani. The correlations of distribution of serovars across Thailand’s regions were found to be similar in pattern for cattle but not for buffaloes. In humans, the serovar distribution in the south differed from other regions. By logistic regression, the results indicated that livestock is more susceptible to infection by serovar Shermani when compared to humans. Conclusions/Significance This study gives a detailed picture of the predominance of Leptospira serovars in relation to region, humans and typical livestock. The broad spatial distribution of seroprevalence was analyzed across and within species as well as regions in Thailand. Our finding may guide public health policy makers to implement appropriate control measures and help to reduce the impact of leptospirosis in Thailand. PMID:28182662

  5. A comparison of methods for smoothing and gap filling time series of remote sensing observations - application to MODIS LAI products

    NASA Astrophysics Data System (ADS)

    Kandasamy, S.; Baret, F.; Verger, A.; Neveux, P.; Weiss, M.

    2013-06-01

    Moderate resolution satellite sensors including MODIS (Moderate Resolution Imaging Spectroradiometer) already provide more than 10 yr of observations well suited to describe and understand the dynamics of earth's surface. However, these time series are associated with significant uncertainties and incomplete because of cloud cover. This study compares eight methods designed to improve the continuity by filling gaps and consistency by smoothing the time course. It includes methods exploiting the time series as a whole (iterative caterpillar singular spectrum analysis (ICSSA), empirical mode decomposition (EMD), low pass filtering (LPF) and Whittaker smoother (Whit)) as well as methods working on limited temporal windows of a few weeks to few months (adaptive Savitzky-Golay filter (SGF), temporal smoothing and gap filling (TSGF), and asymmetric Gaussian function (AGF)), in addition to the simple climatological LAI yearly profile (Clim). Methods were applied to the MODIS leaf area index product for the period 2000-2008 and over 25 sites showed a large range of seasonal patterns. Performances were discussed with emphasis on the balance achieved by each method between accuracy and roughness depending on the fraction of missing observations and the length of the gaps. Results demonstrate that the EMD, LPF and AGF methods were failing because of a significant fraction of gaps (more than 20%), while ICSSA, Whit and SGF were always providing estimates for dates with missing data. TSGF (Clim) was able to fill more than 50% of the gaps for sites with more than 60% (80%) fraction of gaps. However, investigation of the accuracy of the reconstructed values shows that it degrades rapidly for sites with more than 20% missing data, particularly for ICSSA, Whit and SGF. In these conditions, TSGF provides the best performances that are significantly better than the simple Clim for gaps shorter than about 100 days. The roughness of the reconstructed temporal profiles shows large

  6. A comparison of methods for smoothing and gap filling time series of remote sensing observations: application to MODIS LAI products

    NASA Astrophysics Data System (ADS)

    Kandasamy, S.; Baret, F.; Verger, A.; Neveux, P.; Weiss, M.

    2012-12-01

    Moderate resolution satellite sensors including MODIS already provide more than 10 yr of observations well suited to describe and understand the dynamics of the Earth surface. However, these time series are incomplete because of cloud cover and associated with significant uncertainties. This study compares eight methods designed to improve the continuity by filling gaps and the consistency by smoothing the time course. It includes methods exploiting the time series as a whole (Iterative caterpillar singular spectrum analysis (ICSSA), empirical mode decomposition (EMD), low pass filtering (LPF) and Whittaker smoother (Whit)) as well as methods working on limited temporal windows of few weeks to few months (Adaptive Savitzky-Golay filter (SGF), temporal smoothing and gap filling (TSGF) and asymmetric Gaussian function (AGF)) in addition to the simple climatological LAI yearly profile (Clim). Methods were applied to MODIS leaf area index product for the period 2000-2008 over 25 sites showing a large range of seasonal patterns. Performances were discussed with emphasis on the balance achieved by each method between accuracy and roughness depending on the fraction of missing observations and the length of the gaps. Results demonstrate that EMD, LPF and AGF methods were failing in case of significant fraction of gaps (%Gap > 20%), while ICSSA, Whit and SGF were always providing estimates for dates with missing data. TSGF (respectively Clim) was able to fill more than 50% of the gaps for sites with more than 60% (resp. 80%) fraction of gaps. However, investigation of the accuracy of the reconstructed values shows that it degrades rapidly for sites with more than 20% missing data, particularly for ICSSA, Whit and SGF. In these conditions, TSGF provides the best performances significantly better than the simple Clim for gaps shorter than about 100 days. The roughness of the reconstructed temporal profiles shows large differences between the several methods, with a decrease

  7. Increased number of crop types over France in the ISBA-A-gs land surface model : does it improve the regional simulation of LAI ?

    NASA Astrophysics Data System (ADS)

    lafont, Sebastien; Calvet, Alina; Carrer, Dominque; Delire, Christine; Calvet, Jean-Christophe; Alkama, ramdane

    2013-04-01

    Land surface models have at first been designed to represent natural vegetation classified in broad Plant Functional Type (PFT). A better description of the agricultural land is needed to enlarge the accuracy of the model (especially at high resolution) and their range of application (land use studies, climate change...). For example in temperate region, the C3 crops have two different seasonal cycles with a peak LAI in spring or in summer depending on sowing date. A larger number of agricultural PFT have been recently introduced in the ISBA-A-gs land surface model within the SURFEX modelling platform. The SURFEX modelling platform is used in a wide range of applications either in coupled mode or in off-line mode (driven by meteorological forcing). The number of agricultural PFT have been increased from 3 (C3 crops, C4 crops, irrigated C4 crops) to 8 (C3 winter crops, and C3 summer crops both irrigated or not; C4 crops; C4 irrigated crops). The objective is not to implement a full agronomic model but to introduce simple parametrisation which account for the broad differences between these classes. For example summer C3 crops have a prescribed emergence date parameter that differentiate them from winter C3 crops. The irrigation introduced in an earlier version of ISBA-A-gs is based on a simple empirical model based on threshold of soil moisture. We will test the new version of the model over France in a configuration close to the one used by the GEOLAND2 Land Carbon project. The simulations are performed with the high resolution meteorological forcing (8km) SAFRAN over a period of 20 years. We compare the simulated LAI over France with the GEOLAND2 LAI product derived project from the SPOT/VEGETATION sensor. Finally, we discuss the improvement in seasonal cycle and inter-annual variability bring by the new PFTs.

  8. Seroepidemiologic study of three zoonoses (leptospirosis, Q fever, and tularemia) among trappers in Québec, Canada.

    PubMed Central

    Lévesque, B; De Serres, G; Higgins, R; D'Halewyn, M A; Artsob, H; Grondin, J; Major, M; Garvie, M; Duval, B

    1995-01-01

    This study was undertaken to evaluate the prevalence of antibodies against Francisella tularensis, Coxiella burnetii, and certain serovars of Leptospira interrogans among trappers in Québec, Canada. Muskrat trapping was identified as a risk factor for F. tularensis infection, whereas having a cat at home apparently protected trappers against infection by L. interrogans. High percentages of control sera were positive for antibodies against C. burnetii (15%) and L. interrogans (5%), most frequently serovar bratislava. This is the first report of human infection by serovar bratislava in North America. PMID:7583933

  9. [Modello di Management (Mo.Ma) del paziente affetto da schizofrenia: controllo della crisi, mantenimento, prevenzione delle ricadute e recovery con gli antipsicotici LAI].

    PubMed

    Brugnoli, Roberto; Rapinesi, Chiara; Kotzalidis, Georgios D; Marcellusi, Andrea; Mennini, Francesco S; De Filippis, Sergio; Carrus, Dario; Ballerini, Andrea; Francomano, Antonio; Ducci, Giuseppe; Del Casale, Antonio; Girardi, Paolo

    2016-01-01

    RIASSUNTO. La schizofrenia colpisce circa l'1% della popolazione e rappresenta un grave disturbo mentale con un notevole impatto anche sul funzionamento sociale, lavorativo e sulle attività della vita quotidiana. Le persone con schizofrenia hanno un tasso di mortalità superiore di 2-2,5 rispetto a quello della popolazione generale. La non aderenza ai farmaci antipsicotici è uno dei più importanti fattori di rischio per le ricadute e le ospedalizzazioni, sia nei pazienti con disturbo cronico sia al primo episodio, e conseguentemente contribuisce all'aumento dei costi sanitari. Gli antipsicotici atipici LAI possono migliorare l'aderenza al trattamento contribuendo a diminuire i tassi di ricaduta nei pazienti affetti da schizofrenia fin dall'esordio. Gli obiettivi primari nella gestione dei pazienti schizofrenici sono diretti, non solo alla riduzione dei sintomi nel breve termine, ma anche al mantenimento fisico e della funzionalità mentale, migliorando la qualità della vita e promuovendo il recupero del paziente. Scopo. Proporre un modello integrato, basato sulle evidenze, che fornisca un algoritmo efficace per il recupero del paziente schizofrenico e indagare l'efficacia e la sicurezza degli antipsicotici LAI nel trattamento, nel mantenimento, nella prevenzione delle ricadute e nella recovery dei pazienti affetti da schizofrenia. Metodi. Dopo un'accurata analisi di letteratura abbiamo identificato, raccolto e analizzato gli elementi qualificanti per un'ottimale gestione del paziente schizofrenico, definendo un modello di gestione e selezione delle alternative terapeutiche. Conclusioni. Il modello di gestione della schizofrenia proposto potrebbe consentire un migliore recupero funzionale del paziente grazie alla scelta di iniziare il percorso terapeutico, fin dalle prime fasi del disturbo soprattutto se in giovane età e al primo episodio, con un farmaco atipico LAI. All'interno dei farmaci antipsicotici atipici la formulazione LAI rappresenta una scelta

  10. The Legionella pneumophila orphan sensor kinase LqsT regulates competence and pathogen-host interactions as a component of the LAI-1 circuit.

    PubMed

    Kessler, Aline; Schell, Ursula; Sahr, Tobias; Tiaden, André; Harrison, Christopher; Buchrieser, Carmen; Hilbi, Hubert

    2013-02-01

    Legionella pneumophila is an amoeba-resistant opportunistic pathogen that performs cell-cell communication through the signalling molecule 3-hydroxypentadecane-4-one (LAI-1, Legionella autoinducer-1). The lqs (Legionella quorum sensing) gene cluster encodes the LAI-1 autoinducer synthase LqsA, the cognate sensor kinase LqsS and the response regulator LqsR. Here we show that the Lqs system includes an 'orphan' homologue of LqsS termed LqsT. Compared with wild-type L. pneumophila, strains lacking lqsT or both lqsS and lqsT show increased salt resistance, greatly enhanced natural competence for DNA acquisition and impaired uptake by phagocytes. Sensitive novel single round growth assays and competition experiments using Acanthamoeba castellanii revealed that ΔlqsT and ΔlqsS-ΔlqsT, as well as ΔlqsA and other lqs mutant strains are impaired for intracellular growth and cannot compete against wild-type bacteria upon co-infection. In contrast to the ΔlqsS strain, ΔlqsT does not produce extracellular filaments. The phenotypes of the ΔlqsS-ΔlqsT strain are partially complemented by either lqsT or lqsS, but are not reversed by overexpression of lqsA, suggesting that LqsT and LqsS are the sole LAI-1-responsive sensor kinases in L. pneumophila. In agreement with the different phenotypes of the ΔlqsT and ΔlqsS strains, lqsT and lqsS are differentially expressed in the post-exponential growth phase, and transcriptome studies indicated that 90% of the genes, which are downregulated in absence of lqsT, are upregulated in absence of lqsS. Reciprocally regulated genes encode components of a 133 kb genomic 'fitness island' or translocated effector proteins implicated in virulence. Together, these results reveal a unique organization of the L. pneumophila Lqs system comprising two partially antagonistic LAI-1-responsive sensor kinases, LqsT and LqsS, which regulate distinct pools of genes implicated in pathogen-host cell interactions, competence, expression of a

  11. Multilocus sequence analysis of Bacillus thuringiensis serovars navarrensis, bolivia and vazensis and Bacillus weihenstephanensis reveals a common phylogeny.

    PubMed

    Soufiane, Brahim; Baizet, Mathilde; Côté, Jean-Charles

    2013-01-01

    The Bacillus cereus group sensu lato includes six closely-related bacterial species: Bacillus cereus, Bacillus anthracis, Bacillus thuringiensis, Bacillus mycoides, Bacillus pseudomycoides and Bacillus weihenstephanensis. B. thuringiensis is distinguished from the other species mainly by the appearance of an inclusion body upon sporulation. B. weihenstephanensis is distinguished based on its psychrotolerance and the presence of specific signature sequences in the 16S rRNA gene and cspA genes. A total of seven housekeeping genes (glpF, gmK, ilvD, pta, purH, pycA and tpi) from different B. thuringiensis serovars and B. weihenstephanensis strains were amplified and their nucleotide sequences determined. A maximum likelihood phylogenetic tree was inferred from comparisons of the concatenated sequences. B. thuringiensis serovars navarrensis, bolivia and vazensis clustered not with the other B. thuringiensis serovars but rather with the B. weihenstephanensis strains, indicative of a common phylogeny. In addition, specific signature sequences and single nucleotide polymorphisms common to B. thuringiensis serovars navarrensis, bolivia and vazensis and the B. weihenstephanensis strains, and absent in the other B. thuringiensis serovars, were identified.

  12. Genomic comparison of the closely-related Salmonella enterica serovars enteritidis, dublin and gallinarum

    SciTech Connect

    Matthews, T. David; Schmieder, Robert; Silva, Genivaldo G. Z.; Busch, Julia; Cassman, Noriko; Dutilh, Bas E.; Green, Dawn; Matlock, Brian; Heffernan, Brian; Olsen, Gary J.; Hanna, Leigh Farris; Schifferli, Dieter M.; Maloy, Stanley; Dinsdale, Elizabeth A.; Edwards, Robert A.; Cloeckaert, Axel

    2015-06-03

    The Salmonella enterica serovars Enteritidis, Dublin, and Gallinarum are closely related but differ in virulence and host range. To identify the genetic elements responsible for these differences and to better understand how these serovars are evolving, we sequenced the genomes of Enteritidis strain LK5 and Dublin strain SARB12 and compared these genomes to the publicly available Enteritidis P125109, Dublin CT 02021853 and Dublin SD3246 genome sequences. We also compared the publicly available Gallinarum genome sequences from biotype Gallinarum 287/91 and Pullorum RKS5078. Using bioinformatic approaches, we identified single nucleotide polymorphisms, insertions, deletions, and differences in prophage and pseudogene content between strains belonging to the same serovar. Through our analysis we also identified several prophage cargo genes and pseudogenes that affect virulence and may contribute to a host-specific, systemic lifestyle. These results strongly argue that the Enteritidis, Dublin and Gallinarum serovars of Salmonella enterica evolve by acquiring new genes through horizontal gene transfer, followed by the formation of pseudogenes. The loss of genes necessary for a gastrointestinal lifestyle ultimately leads to a systemic lifestyle and niche exclusion in the host-specific serovars.

  13. Human migration is important in the international spread of exotic Salmonella serovars in animal and human populations.

    PubMed

    Iveson, J B; Bradshaw, S D; How, R A; Smith, D W

    2014-11-01

    The exposure of indigenous humans and native fauna in Australia and the Wallacea zoogeographical region of Indonesia to exotic Salmonella serovars commenced during the colonial period and has accelerated with urbanization and international travel. In this study, the distribution and prevalence of exotic Salmonella serovars are mapped to assess the extent to which introduced infections are invading native wildlife in areas of high natural biodiversity under threat from expanding human activity. The major exotic Salmonella serovars, Bovismorbificans, Derby, Javiana, Newport, Panama, Saintpaul and Typhimurium, isolated from wildlife on populated coastal islands in southern temperate areas of Western Australia, were mostly absent from reptiles and native mammals in less populated tropical areas of the state. They were also not recorded on the uninhabited Mitchell Plateau or islands of the Bonaparte Archipelago, adjacent to south-eastern Indonesia. Exotic serovars were, however, isolated in wildlife on 14/17 islands sampled in the Wallacea region of Indonesia and several islands off the west coast of Perth. Increases in international tourism, involving islands such as Bali, have resulted in the isolation of a high proportion of exotic serovar infections suggesting that densely populated island resorts in the Asian region are acting as staging posts for the interchange of Salmonella infections between tropical and temperate regions.

  14. Leptospira weilii serovar Topaz, a new member of the Tarassovi serogroup isolated from a bovine source in Queensland, Australia.

    PubMed

    Corney, B G; Slack, A T; Symonds, M L; Dohnt, M F; McClintock, C S; McGowan, M R; Smythe, L D

    2008-10-01

    This paper reports on a Leptospira isolate of bovine origin and its identification as belonging to a previously unknown serovar, for which the name Topaz is proposed. The isolate (94-79970/3) was cultured from bovine urine from a north Queensland dairy farm in Australia. Strain 94-79970/3 grew at 30 degrees C in Ellinghausen McCullough Johnson Harris (EMJH) medium but failed to grow at 13 degrees C in EMJH medium or in the presence of 8-azaguanine. Serologically, strain 94-79970/3 produced titres against the Leptospira borgpetersenii serovar Tarassovi, the reference strain for the Tarassovi serogroup; however, no significant titres to any other serovars within the serogroup were obtained. Using 16S rRNA and DNA gyrase subunit B gene analysis, strain 94-79970/3 was identified as a member of the species Leptospira weilii. We propose that the serovar be named Topaz, after the location where the original isolate was obtained. The reference strain for this serovar is 94-79970/3 (=KIT 94-79970/3=LT722).

  15. Chloramphenicol and tetracycline decrease motility and increase invasion and attachment gene expression in specific isolates of multidrug-resistant Salmonella enterica serovar Typhimurium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica serovar Typhimurium (S. Typhimurium) is one of the most common serovars isolated from humans and livestock, and over 35 percent of these isolates are resistant to three or more antibiotics. Multidrug-resistant (MDR) Salmonella is a public health concern as it is associated with i...

  16. Antimicrobial resistance-conferring plasmids with similarity to virulence plasmids from avian pathogenic Escherichia coli strains in Salmonella enterica serovar Kentucky isolates from poultry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella enterica, a leading cause of food-borne gastroenteritis worldwide, may be found in any raw food of animal, vegetable, or fruit origin. Salmonella serovars differ in distribution, virulence, and host specificity. Salmonella enterica serovar Kentucky, though often found in the food supply, ...

  17. Poultry-Associated Salmonella enterica subsp. enterica Serovar 4,12:d:− Reveals High Clonality and a Distinct Pathogenicity Gene Repertoire ▿ †

    PubMed Central

    Huehn, Stephan; Bunge, Cornelia; Junker, Ernst; Helmuth, Reiner; Malorny, Burkhard

    2009-01-01

    A European baseline survey during the years 2005 and 2006 has revealed that the monophasic Salmonella enterica subsp. enterica serovar 4,12:d:− was, with a prevalence of 23.6%, the most frequently isolated serovar in German broiler flocks. In Denmark and the United Kingdom, its serovar prevalences were 15.15% and 2.8%, respectively. Although poultry is a major source of human salmonellosis, serovar 4,12:d:− is rarely isolated in humans (approximately 0.09% per year). Molecular typing studies using pulsed-field gel electrophoresis and DNA microarray analysis show that the serovar is highly clonal and lacks genes with known contributions to pathogenicity. In contrast to other poultry-associated serovars, all strains were susceptible to 17 antimicrobial agents tested and did not encode any resistance determinant. Furthermore, serovar 4,12:d:− lacked the genes involved in galactonate metabolism and in the glycolysis and glyconeogenesis important for energy production in the cells. The conclusion of the study is that serovar 4,12:d:− seems to be primarily adapted to broilers and therefore causes only rare infections in humans. PMID:19114530

  18. A comparative study on invasion, survival, modulation of oxidative burst, and nitric oxide responses of macrophages (HD11), and systemic infection in chickens by prevalent poultry Salmonella serovars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Poultry is a major reservoir for foodborne Salmonella serovars. Salmonella Typhimurium, S. Enteritidis, S. Heidelberg, S. Kentucky, and S. Senftenberg are the most prevalent serovars in poultry. Information concerning the interactions between different Salmonella species and host cells in poultry i...

  19. The role of flagella and chemotaxis genes in host pathogen interaction of the host adapted Salmonella enterica serovar Dublin compared to the broad host range serovar S. Typhimurium

    PubMed Central

    2013-01-01

    Background The importance of flagella and chemotaxis genes in host pathogen interaction in Salmonella enterica is mainly based on studies of the broad host range serovar, S. Typhimurium, while little is known on the importance in host specific and host adapted serovars, such as S. Dublin. In the current study we have used previously characterized insertion mutants in flagella and chemotaxis genes to investigate this and possible differences in the importance between the two serovars. Results fliC (encoding the structural protein of the flagella) was essential for adhesion and fliC and cheB (CheB restores the chemotaxis system to pre-stimulus conformation) were essential for invasion of S. Dublin into epithelial Int407 cells. In S. Typhimurium, both lack of flagella (fliC/fljB double mutant) and cheB influenced adhesion, and invasion was influenced by lack of both cheA (the histidine-kinase of the chemotaxis system), fliC/fljB and cheB mutation. Uptake in J774A.1 macrophage cells was significantly reduced in cheA, cheB and fliC mutants of S. Dublin, while cheA was dispensable in S. Typhimurium. Removal of flagella in both serotypes caused an increased ability to propagate intracellular in J774 macrophage cells and decreased cytotoxicity toward these cells. Flagella and chemotaxis genes were found not to influence the oxidative response. The induction of IL-6 from J774A-1 cells depended on the presence of flagella in S. Typhimurium, whilst this was not the case following challenge with S. Dublin. Addition of fliC from S. Typhimurium in trans to a fliC mutant of S. Dublin increased cytotoxicity but it did not increase the IL-6 production. Flagella were demonstrated to contribute to the outcome of infection following oral challenge of mice in S. Dublin, while an S. Typhimurium fliC/fljB mutant showed increased virulence following intra peritoneal challenge. Conclusions The results showed that flagella and chemotaxis genes differed in their role in host pathogen

  20. Prevalence of Salmonella Isolates from Chicken and Pig Slaughterhouses and Emergence of Ciprofloxacin and Cefotaxime Co-Resistant S. enterica Serovar Indiana in Henan, China

    PubMed Central

    Bai, Li; Lan, Ruiting; Zhang, Xiuli; Cui, Shenghui; Xu, Jin; Guo, Yunchang; Li, Fengqin; Zhang, Ding

    2015-01-01

    The prevalence of Salmonella from chicken and pig slaughterhouses in Henan, China and antimicrobial susceptibility of these isolates to antibiotics was determined. From 283 chicken samples and 240 pig samples collected, 128 and 70 Salmonella isolates were recovered with an isolation rate of 45.2 and 29.2% respectively. The predominant serovars in chicken samples were S. enterica serovar Enteritidis, S. enterica serovar Hadar and S. enterica serovar Indiana, while those in pig samples were S. enterica serovar Typhimurium, S. enterica serovar Derby and S. enterica serovar Enteritidis. Resistance to ciprofloxacin was 8.6 and 10.0% for isolates from chickens and pigs respectively, whereas resistance to cefotaxime was 5.5 and 8.6%, respectively. Multidrug resistance (resistance to three or more classes of antimicrobial agent) was markedly higher in pig isolates (57.1%) than in chicken isolates (39.8%). Of particular concern was the detection of ciprofloxacin and cefotaxime co-resistant S. enterica serovar Indiana isolates, which pose risk to public health. All 16 S. enterica serovar Indiana isolates detected were resistant to ciprofloxacin, among which 11 were co-resistant to cefotaxime. The S. enterica serovar Indiana isolates accumulated point mutations in quinolone resistance determination regions of gyrA (S83F/D87G or S83F/D87N) and parC (T57S/S80R). Two plasmid mediated quinolone resistant determinants were found with aac (6')-Ib-cr and oqxAB in 16 and 12 S. enterica serovar Indiana isolates respectively. Cefotaxime-resistance of S. enterica serovar Indiana was associated with the acquisition of a blaCTX-M-65 gene. The potential risk of ciprofloxacin and cefotaxime co-resistant S. enterica serovar Indiana infection is a significant concern due to limited alternative treatment options. Reduction of Salmonella in chicken and pig slaughterhouses, in particular, ciprofloxacin and cefotaxime co-resistant S. enterica serovar Indiana will be an important measure to reduce

  1. Salmonella enterica serovar Minnesota urosepsis in a patient with Crohn's disease in the absence of recent or current gastrointestinal symptoms.

    PubMed

    Steinebrunner, Niels; Sandig, Catharina; Zimmermann, Stefan; Stremmel, Wolfgang; Eisenbach, Christoph; Mischnik, Alexander

    2013-09-01

    Salmonella enterica serovar Minnesota is a rarely isolated organism in clinical samples mainly grown from stool cultures. Sepsis due to Salmonella is known in severely immunocompromised patients, but so far urosepsis due to S. enterica serovar Minnesota has not been described. We report a case of a 31-year-old patient suffering from Crohn's disease treated with infliximab and azathioprine, in whom was implanted a double-J ureteric catheter for urolithiasis. The patient presented with urinary tract infection and severe sepsis. S. enterica serovar Minnesota was grown from urine and blood cultures. After empiric antimicrobial treatment with meropenem and vancomycin, treatment was changed to ceftriaxone. Antimicrobial treatment was continued for a total of 3 weeks without evidence of Salmonella recurrence on follow-up visits. Salmonella spp. rarely cause urinary tract infection and sepsis. However, in immunocompromised patients, non-typhoidal salmonellosis merits a thorough clinical and microbiological evaluation.

  2. Isolation of leptospira Serovars Canicola and Copenhageni from cattle urine in the state of ParanÁ, Brazil

    PubMed Central

    Zacarias, Francielle Gibson da Silva; Vasconcellos, Silvio Arruda; Anzai, Eleine Kuroki; Giraldi, Nilson; de Freitas, Julio Cesar; Hartskeerl, Rudy

    2008-01-01

    In 2001, 698 urine samples were randomly collected from cattle at a slaughterhouse in the State of Paraná, Brazil. Direct examination using dark field microscopy was carried out immediately after collection. Five putative positive samples were cultured in modified EMJH medium, yielding two positive cultures (LO-14 and LO-10). Typing with monoclonal antibodies revealed that the two isolates were similar to Canicola (LO-14) and Copenhageni (LO-10). Microscopic agglutination test results show that Hardjo is the most common serovar in cattle in Brazil. Rats and dogs are the common maintenance hosts of serovars Copenhageni and Canicola. The excretion of highly pathogenic serovars such as Copenhageni and Canicola by cattle can represent an increasing risk for severe leptospirosis is large populations, mainly living in rural areas. PMID:24031301

  3. Isolation of leptospira Serovars Canicola and Copenhageni from cattle urine in the state of ParanÁ, Brazil.

    PubMed

    Zacarias, Francielle Gibson da Silva; Vasconcellos, Silvio Arruda; Anzai, Eleine Kuroki; Giraldi, Nilson; de Freitas, Julio Cesar; Hartskeerl, Rudy

    2008-10-01

    In 2001, 698 urine samples were randomly collected from cattle at a slaughterhouse in the State of Paraná, Brazil. Direct examination using dark field microscopy was carried out immediately after collection. Five putative positive samples were cultured in modified EMJH medium, yielding two positive cultures (LO-14 and LO-10). Typing with monoclonal antibodies revealed that the two isolates were similar to Canicola (LO-14) and Copenhageni (LO-10). Microscopic agglutination test results show that Hardjo is the most common serovar in cattle in Brazil. Rats and dogs are the common maintenance hosts of serovars Copenhageni and Canicola. The excretion of highly pathogenic serovars such as Copenhageni and Canicola by cattle can represent an increasing risk for severe leptospirosis is large populations, mainly living in rural areas.

  4. Proteolytic Inhibition of Salmonella enterica Serovar Typhimurium-Induced Activation of the Mitogen-Activated Protein Kinases ERK and JNK in Cultured Human Intestinal Cells

    PubMed Central

    Mynott, Tracey L.; Crossett, Ben; Prathalingam, S. Radhika

    2002-01-01

    Bromelain, a mixture of cysteine proteases from pineapple stems, blocks signaling by the mitogen-activated protein (MAP) kinases extracellular regulated kinase 1 (ERK-1) and ERK-2, inhibits inflammation, and protects against enterotoxigenic Escherichia coli infection. In this study, we examined the effect of bromelain on Salmonella enterica serovar Typhimurium infection, since an important feature of its pathogenesis is its ability to induce activation of ERK-1 and ERK-2, which leads to internalization of bacteria and induction of inflammatory responses. Our results show that bromelain dose dependently blocks serovar Typhimurium-induced ERK-1, ERK-2, and c-Jun NH2-terminal kinase (JNK) activation in Caco-2 cells. Bromelain also blocked signaling induced by carbachol and anisomycin, pharmacological MAP kinase agonists. Despite bromelain inhibition of serovar Typhimurium-induced MAP kinase signaling, it did not prevent subsequent invasion of the Caco-2 cells by serovar Typhimurium or alter serovar Typhimurium -induced decreases in resistance across Caco-2 monolayers. Surprisingly, bromelain also did not block serovar Typhimurium-induced interleukin-8 (IL-8) secretion but synergized with serovar Typhimurium to enhance IL-8 production. We also found that serovar Typhimurium does not induce ERK phosphorylation in Caco-2 cells in the absence of serum but that serovar Typhimurium-induced invasion and decreases in monolayer resistance are unaffected. Collectively, these data indicate that serovar Typhimurium-induced invasion of Caco-2 cells, changes in the resistance of epithelial cell monolayers, and IL-8 production can occur independently of the ERK and JNK signaling pathways. Data also confirm that bromelain is a novel inhibitor of MAP kinase signaling pathways and suggest a novel role for proteases as inhibitors of signal transduction pathways in intestinal epithelial cells. PMID:11748167

  5. Proteolytic inhibition of Salmonella enterica serovar typhimurium-induced activation of the mitogen-activated protein kinases ERK and JNK in cultured human intestinal cells.

    PubMed

    Mynott, Tracey L; Crossett, Ben; Prathalingam, S Radhika

    2002-01-01

    Bromelain, a mixture of cysteine proteases from pineapple stems, blocks signaling by the mitogen-activated protein (MAP) kinases extracellular regulated kinase 1 (ERK-1) and ERK-2, inhibits inflammation, and protects against enterotoxigenic Escherichia coli infection. In this study, we examined the effect of bromelain on Salmonella enterica serovar Typhimurium infection, since an important feature of its pathogenesis is its ability to induce activation of ERK-1 and ERK-2, which leads to internalization of bacteria and induction of inflammatory responses. Our results show that bromelain dose dependently blocks serovar Typhimurium-induced ERK-1, ERK-2, and c-Jun NH(2)-terminal kinase (JNK) activation in Caco-2 cells. Bromelain also blocked signaling induced by carbachol and anisomycin, pharmacological MAP kinase agonists. Despite bromelain inhibition of serovar Typhimurium-induced MAP kinase signaling, it did not prevent subsequent invasion of the Caco-2 cells by serovar Typhimurium or alter serovar Typhimurium -induced decreases in resistance across Caco-2 monolayers. Surprisingly, bromelain also did not block serovar Typhimurium-induced interleukin-8 (IL-8) secretion but synergized with serovar Typhimurium to enhance IL-8 production. We also found that serovar Typhimurium does not induce ERK phosphorylation in Caco-2 cells in the absence of serum but that serovar Typhimurium-induced invasion and decreases in monolayer resistance are unaffected. Collectively, these data indicate that serovar Typhimurium-induced invasion of Caco-2 cells, changes in the resistance of epithelial cell monolayers, and IL-8 production can occur independently of the ERK and JNK signaling pathways. Data also confirm that bromelain is a novel inhibitor of MAP kinase signaling pathways and suggest a novel role for proteases as inhibitors of signal transduction pathways in intestinal epithelial cells.

  6. SEROVARS AND ANTIMICROBIAL RESISTANCE OF Salmonella spp. ISOLATED FROM TURKEY AND BROILER CARCASSES IN SOUTHERN BRAZIL BETWEEN 2004 AND 2006

    PubMed Central

    PALMEIRA, Andre; dos SANTOS, Luciana Ruschel; BORSOI, Anderlise; RODRIGUES, Laura Beatriz; CALASANS, Max; do NASCIMENTO, Vladimir Pinheiro

    2016-01-01

    Salmonella spp. causes diseases in fowls, when species-specific serovars (Salmonella Pullorum and S.Gallinarum) are present in flocks, and public health problems, when non-typhoid serovars are isolated, as well as possible bacterial resistance induced by the preventive and therapeutic use of antimicrobials in animal production. This study describes the serovars and bacterial resistance of 280Salmonella spp. strains isolated from turkey and broiler carcasses in Southern Brazil between 2004 and 2006. SalmonellaEnteritidis was the most prevalent serovar (55.7%), followed by Heidelberg (5.0%), Agona (4.3%), Bredeney (3.9%), Hadar (3.2%), and Typhimurium (2.9%). Tennessee and S. Enterica subspecies enterica(O: 4.5) were isolated only in turkeys, and Hadar (18.6%) was the most prevalent serovar in this species. Antimicrobial susceptibility tests were performed in 178 isolates (43 from turkeys and 135 from broilers). All isolates were sensitive to amoxicillin + clavulanic acid, polymyxin B, ciprofloxacin, and norfloxacin, and were resistant to bacitracin and penicillin. Broiler carcass isolates showed resistance to nalidixic acid (48.9%), nitrofurantoin (34.3%), neomycin (9.6%), tetracycline (5.2%), and kanamycin (8.9%); and turkey carcass isolates were resistant to nalidixic acid (62.8%), tetracycline (34.9%), and neomycin (30.2%), with a significant difference in turkeys when compared to broiler carcass isolates. These results indicate the need for judicious use of antimicrobials in livestock production, given that the serovars identified are potential causes of food poisoning. PMID:27007562

  7. Increased efficacy of inactivated vaccine candidates prepared with Salmonella enterica serovar Typhimurium strains of predominant genotypes in ducks.

    PubMed

    Youn, S Y; Kwon, Y K; Song, C S; Lee, H J; Jeong, O M; Choi, B K; Jung, S C; Kang, M S

    2016-08-01

    Salmonella enterica serovar Typhimurium has been a major causative agent of food-borne human disease, mainly due to consumption of contaminated food animal products. In particular, ducks serve as a reservoir of serovar Typhimurium, and are one of the common sources of human infection. To prevent infection of ducks, and therefore minimize human infection, it is critical to control the persistent epidemic strains in ducks. Here, we analyzed the genetic diversity and virulence of serovar Typhimurium isolates from ducks in Korea to identify the predominant strains that might be used as efficient vaccine candidates for ducks. Among the isolates, 2 representative isolates (ST26 and ST76) of predominant genotypes were selected as vaccine strains on the basis of genotypic analysis by pulsed-field gel electrophoresis and DNA microarrays. Two-week-old ducks were then injected intramuscularly with inactivated vaccine candidates prepared using ST26 or ST76 (10(8) cfu/0.5 mL/duck or 10(9) cfu/0.5 mL/duck), and oral challenge with a highly virulent serovar Typhimurium strain (10(9) cfu/0.5 mL/duck) was carried out 2 wk later. Shedding of the challenge strain was significantly decreased in group 2 after vaccination. The antibody levels by enzyme-linked immunosorbent assay in all vaccinated groups were enhanced significantly (P < 0.05) compared to the unvaccinated control group. Overall, vaccination with ST26 or ST76 reduced bacterial shedding and colonization in internal organs, and induced elevated antibody response. In particular, serovar Typhimurium ST26 (10(8) cfu/0.5 mL/duck) was the most effective vaccine candidate, which can provide efficient protection against serovar Typhimurium in ducks with higher effectiveness compared to a commercial vaccine currently used worldwide.

  8. SEROVARS AND ANTIMICROBIAL RESISTANCE OF Salmonella spp. ISOLATED FROM TURKEY AND BROILER CARCASSES IN SOUTHERN BRAZIL BETWEEN 2004 AND 2006.

    PubMed

    Palmeira, Andre; Santos, Luciana Ruschel dos; Borsoi, Anderlise; Rodrigues, Laura Beatriz; Calasans, Max; Nascimento, Vladimir Pinheiro do

    2016-01-01

    Salmonella spp. causes diseases in fowls, when species-specific serovars (Salmonella Pullorum and S.Gallinarum) are present in flocks, and public health problems, when non-typhoid serovars are isolated, as well as possible bacterial resistance induced by the preventive and therapeutic use of antimicrobials in animal production. This study describes the serovars and bacterial resistance of 280 Salmonella spp. strains isolated from turkey and broiler carcasses in Southern Brazil between 2004 and 2006. Salmonella Enteritidis was the most prevalent serovar (55.7%), followed by Heidelberg (5.0%), Agona (4.3%), Bredeney (3.9%), Hadar (3.2%), and Typhimurium (2.9%). Tennessee and S. Enterica subspecies enterica(O: 4.5) were isolated only in turkeys, and Hadar (18.6%) was the most prevalent serovar in this species. Antimicrobial susceptibility tests were performed in 178 isolates (43 from turkeys and 135 from broilers). All isolates were sensitive to amoxicillin + clavulanic acid, polymyxin B, ciprofloxacin, and norfloxacin, and were resistant to bacitracin and penicillin. Broiler carcass isolates showed resistance to nalidixic acid (48.9%), nitrofurantoin (34.3%), neomycin (9.6%), tetracycline (5.2%), and kanamycin (8.9%); and turkey carcass isolates were resistant to nalidixic acid (62.8%), tetracycline (34.9%), and neomycin (30.2%), with a significant difference in turkeys when compared to broiler carcass isolates. These results indicate the need for judicious use of antimicrobials in livestock production, given that the serovars identified are potential causes of food poisoning.

  9. Attachment of Salmonella serovars and Listeria monocytogenes to stainless steel and plastic conveyor belts.

    PubMed

    Veluz, G A; Pitchiah, S; Alvarado, C Z

    2012-08-01

    In poultry industry, cross-contamination due to processing equipment and contact surfaces is very common. This study examined the extent of bacterial attachment to 6 different types and design of conveyor belts: stainless steel-single loop, stainless steel-balance weave, polyurethane with mono-polyester fabric, acetal, polypropylene mesh top, and polypropylene. Clean conveyor belts were immersed separately in either a cocktail of Salmonella serovars (Salmonella Typhimurium and Salmonella Enteritidis) or Listeria monocytogenes strains (Scott A, Brie 1, ATCC 6744) for 1 h at room temperature. Soiled conveyor chips were dipped in poultry rinses contaminated with Salmonella or Listeria cocktail and incubated at 10°C for 48 h. The polyurethane with mono-polyester fabric conveyor belt and chip exhibited a higher (P<0.05) mean number of attached Salmonella serovars (clean: 1.6 to 3.6 cfu/cm2; soiled: 0.8 to 2.4 cfu/cm2) and L. monocytogenes (clean: 4.0 to 4.3 cfu/cm2; soiled: 0.3 to 2.1 cfu/cm2) in both clean and soiled conditions. The stainless steel conveyor belt attached a lower (P<0.05) number of Salmonella serovars (clean: 0 to 2.6 cfu/cm2; soiled: 0.4 to 1.3 cfu/cm2) and L. monocytogenes (clean: 0.4 to 2.9 cfu/cm2; soiled: 0 to 0.7 cfu/cm2) than the polymeric materials, indicating weaker adhesion properties. Plastic conveyor belts exhibited stronger bacterial adhesion compared with stainless steel. The result suggests the importance of selecting the design and finishes of conveyor belt materials that are most resistant to bacterial attachment.

  10. Genomic Evidence Reveals Numerous Salmonella enterica Serovar Newport Reintroduction Events in Suwannee Watershed Irrigation Ponds

    PubMed Central

    Jackson, Scott A.; Gangiredla, Jayanthi; Wang, Weimin; Liu, Huanli; Tall, Ben D.; Beaubrun, Junia Jean-Gilles; Jay-Russell, Michele; Vellidis, George; Elkins, Christopher A.

    2015-01-01

    Our previous work indicated a predominance (56.8%) of Salmonella enterica serovar Newport among isolates recovered from irrigation ponds used in produce farms over a 2-year period (B. Li et al., Appl Environ Microbiol 80:6355–6365, http://dx.doi.org/10.1128/AEM.02063-14). This observation provided a valuable set of metrics to explore an underaddressed issue of environmental survival of Salmonella by DNA microarray. Microarray analysis correctly identified all the isolates (n = 53) and differentiated the S. Newport isolates into two phylogenetic lineages (S. Newport II and S. Newport III). Serovar distribution analysis showed no instances where the same serovar was recovered from a pond for more than a month. Furthermore, during the study, numerous isolates with an indistinguishable genotype were recovered from different ponds as far as 180 km apart for time intervals as long as 2 years. Although isolates within either lineage were phylogenetically related as determined by microarray analysis, subtle genotypic differences were detected within the lineages, suggesting that isolates in either lineage could have come from several unique hosts. For example, strains in four different subgroups (A, B, C, and D) possessed an indistinguishable genotype within their subgroups as measured by gene differences, suggesting that strains in each subgroup shared a common host. Based on this comparative genomic evidence and the spatial and temporal factors, we speculated that the presence of Salmonella in the ponds was likely due to numerous punctuated reintroduction events associated with several different but common hosts in the environment. These findings may have implications for the development of strategies for efficient and safe irrigation to minimize the risk of Salmonella outbreaks associated with fresh produce. PMID:26386063

  11. Preliminary Investigations on the Distribution of Leptospira Serovars in Domestic Animals in North-west Morocco.

    PubMed

    Benkirane, A; Noury, S; Hartskeerl, R A; Goris, M G A; Ahmed, A; Nally, J E

    2016-04-01

    Leptospirosis is a neglected zoonosis of global importance with a complex epidemiology that affects humans, domestic and wild mammals. However, due to the diversity of clinical signs and difficulties of establishing a confirmatory laboratory diagnosis, the disease remains poorly investigated, particularly in the developing world. In Morocco, a descriptive study of the seroprevalence of Leptospira infection in animals has never been undertaken. To fill this gap, the current study was conducted on a subset of animals in north-west Morocco as a preliminary step towards understanding the epidemiological patterns of animal leptospirosis in the country. The study was conducted on 289 serum samples collected between January and April 2012 from dogs, cattle, sheep, goats and donkeys in the areas of Rabat-Temara, Sidi Kacem and Oulmes. All serum samples were tested by the MAT with 14 reference strains of the most prevalent pathogenic serovars of Leptospira and two serovars of non-pathogenic Leptospira. The overall seroprevalence of Leptospira in cattle, sheep, goats, dogs and donkeys was 15%, 18%, 20%, 21% and 20%, respectively. The most prevalent serogroups found in each species were Ballum, Sejroe, and Australis in cattle, Ballum, Australis and Sejroe in sheep, Australis and Ballum in goats, Javanica and Australis in donkey and Australis, Ballum and Canicola in dogs. Of all the serogroups tested in this study, Icterohaemorrhagiae, the only serogroup which has been previously reported in humans in Morocco, was rarely reactive. The majority of reactive sera were collected from low land areas. A large number of sera samples classified as seronegative when tested against pathogenic leptospires were positive when tested against non-pathogenic leptospires; this is suggestive of possible novel, as yet unclassified, Leptospira serovars in Morocco. Eleven of thirteen sheep urine samples were positive by real-time PCR confirming their role as Leptospira carriers in Morocco.

  12. Epidemiology of a Salmonella enterica subsp. enterica serovar Typhimurium strain associated with a songbird outbreak.

    PubMed

    Hernandez, Sonia M; Keel, Kevin; Sanchez, Susan; Trees, Eija; Gerner-Smidt, Peter; Adams, Jennifer K; Cheng, Ying; Ray, Al; Martin, Gordon; Presotto, Andrea; Ruder, Mark G; Brown, Justin; Blehert, David S; Cottrell, Walter; Maurer, John J

    2012-10-01

    Salmonella enterica subsp. enterica serovar Typhimurium is responsible for the majority of salmonellosis cases worldwide. This Salmonella serovar is also responsible for die-offs in songbird populations. In 2009, there was an S. Typhimurium epizootic reported in pine siskins in the eastern United States. At the time, there was also a human outbreak with this serovar that was associated with contaminated peanuts. As peanuts are also used in wild-bird food, it was hypothesized that the pine siskin epizootic was related to this human outbreak. A comparison of songbird and human S. Typhimurium pulsed-field gel electrophoresis (PFGE) patterns revealed that the epizootic was attributed not to the peanut-associated strain but, rather, to a songbird strain first characterized from an American goldfinch in 1998. This same S. Typhimurium strain (PFGE type A3) was also identified in the PulseNet USA database, accounting for 137 of 77,941 total S. Typhimurium PFGE entries. A second molecular typing method, multiple-locus variable-number tandem-repeat analysis (MLVA), confirmed that the same strain was responsible for the pine siskin epizootic in the eastern United States but was distinct from a genetically related strain isolated from pine siskins in Minnesota. The pine siskin A3 strain was first encountered in May 2008 in an American goldfinch and later in a northern cardinal at the start of the pine siskin epizootic. MLVA also confirmed the clonal nature of S. Typhimurium in songbirds and established that the pine siskin epizootic strain was unique to the finch family. For 2009, the distribution of PFGE type A3 in passerines and humans mirrored the highest population density of pine siskins for the East Coast.

  13. The Type III Secretion System Effector SptP of Salmonella enterica Serovar Typhi.

    PubMed

    Johnson, Rebecca; Byrne, Alexander; Berger, Cedric N; Klemm, Elizabeth; Crepin, Valerie F; Dougan, Gordon; Frankel, Gad

    2017-02-15

    Strains of the various Salmonella enterica serovars cause gastroenteritis or typhoid fever in humans, with virulence depending on the action of two type III secretion systems (Salmonella pathogenicity island 1 [SPI-1] and SPI-2). SptP is a Salmonella SPI-1 effector, involved in mediating recovery of the host cytoskeleton postinfection. SptP requires a chaperone, SicP, for stability and secretion. SptP has 94% identity between S. enterica serovar Typhimurium and S Typhi; direct comparison of the protein sequences revealed that S Typhi SptP has numerous amino acid changes within its chaperone-binding domain. Subsequent comparison of ΔsptP S Typhi and S. Typhimurium strains demonstrated that, unlike SptP in S. Typhimurium, SptP in S Typhi was not involved in invasion or cytoskeletal recovery postinfection. Investigation of whether the observed amino acid changes within SptP of S Typhi affected its function revealed that S Typhi SptP was unable to complement S. Typhimurium ΔsptP due to an absence of secretion. We further demonstrated that while S. Typhimurium SptP is stable intracellularly within S Typhi, S Typhi SptP is unstable, although stability could be recovered following replacement of the chaperone-binding domain with that of S. Typhimurium. Direct assessment of the strength of the interaction between SptP and SicP of both serovars via bacterial two-hybrid analysis demonstrated that S Typhi SptP has a significantly weaker interaction with SicP than the equivalent proteins in S. Typhimurium. Taken together, our results suggest that changes within the chaperone-binding domain of SptP in S Typhi hinder binding to its chaperone, resulting in instability, preventing translocation, and therefore restricting the intracellular activity of this effector.

  14. Salmonella enterica Serovar Kentucky Flagella Are Required for Broiler Skin Adhesion and Caco-2 Cell Invasion.

    PubMed

    Salehi, Sanaz; Howe, Kevin; Lawrence, Mark L; Brooks, John P; Bailey, R Hartford; Karsi, Attila

    2017-01-15

    Nontyphoidal Salmonella strains are the main source of pathogenic bacterial contamination in the poultry industry. Recently, Salmonella enterica serovar Kentucky has been recognized as the most prominent serovar on carcasses in poultry-processing plants. Previous studies showed that flagella are one of the main factors that contribute to bacterial attachment to broiler skin. However, the precise role of flagella and the mechanism of attachment are unknown. There are two different flagellar subunits (fliC and fljB) expressed alternatively in Salmonella enterica serovars using phase variation. Here, by making deletions in genes encoding flagellar structural subunits (flgK, fliC, and fljB), and flagellar motor (motA), we were able to differentiate the role of flagella and their rotary motion in the colonization of broiler skin and cellular attachment. Utilizing a broiler skin assay, we demonstrated that the presence of FliC is necessary for attachment to broiler skin. Expression of the alternative flagellar subunit FljB enables Salmonella motility, but this subunit is unable to mediate tight attachment. Deletion of the flgK gene prevents proper flagellar assembly, making Salmonella significantly less adherent to broiler skin than the wild type. S Kentucky with deletions in all three structural genes, fliC, fljB, and flgK, as well as a flagellar motor mutant (motA), exhibited less adhesion and invasion of Caco-2 cells, while an fljB mutant was as adherent and invasive as the wild-type strain.

  15. Epidemiology of a Salmonella enterica subsp. enterica Serovar Typhimurium Strain Associated with a Songbird Outbreak

    PubMed Central

    Hernandez, Sonia M.; Keel, Kevin; Sanchez, Susan; Trees, Eija; Gerner-Smidt, Peter; Adams, Jennifer K.; Cheng, Ying; Ray, Al; Martin, Gordon; Presotto, Andrea; Ruder, Mark G.; Brown, Justin; Blehert, David S.; Cottrell, Walter

    2012-01-01

    Salmonella enterica subsp. enterica serovar Typhimurium is responsible for the majority of salmonellosis cases worldwide. This Salmonella serovar is also responsible for die-offs in songbird populations. In 2009, there was an S. Typhimurium epizootic reported in pine siskins in the eastern United States. At the time, there was also a human outbreak with this serovar that was associated with contaminated peanuts. As peanuts are also used in wild-bird food, it was hypothesized that the pine siskin epizootic was related to this human outbreak. A comparison of songbird and human S. Typhimurium pulsed-field gel electrophoresis (PFGE) patterns revealed that the epizootic was attributed not to the peanut-associated strain but, rather, to a songbird strain first characterized from an American goldfinch in 1998. This same S. Typhimurium strain (PFGE type A3) was also identified in the PulseNet USA database, accounting for 137 of 77,941 total S. Typhimurium PFGE entries. A second molecular typing method, multiple-locus variable-number tandem-repeat analysis (MLVA), confirmed that the same strain was responsible for the pine siskin epizootic in the eastern United States but was distinct from a genetically related strain isolated from pine siskins in Minnesota. The pine siskin A3 strain was first encountered in May 2008 in an American goldfinch and later in a northern cardinal at the start of the pine siskin epizootic. MLVA also confirmed the clonal nature of S. Typhimurium in songbirds and established that the pine siskin epizootic strain was unique to the finch family. For 2009, the distribution of PFGE type A3 in passerines and humans mirrored the highest population density of pine siskins for the East Coast. PMID:22885752

  16. Extracellular polysaccharides associated with thin aggregative fimbriae of Salmonella enterica serovar enteritidis.

    PubMed

    White, A P; Gibson, D L; Collinson, S K; Banser, P A; Kay, W W

    2003-09-01

    Lipopolysaccharide (LPS) O polysaccharide was identified as the principle factor impeding intercellular formation of intact thin aggregative fimbriae (Tafi) in Salmonella enterica serovar Enteritidis. The extracellular nucleation-precipitation assembly pathway for these organelles was investigated by quantifying fimbrial formation between deltaagfA (AgfA recipient) and deltaagfB (AgfA donor) cells harboring mutations in LPS (galE::Tn10) and/or cellulose (deltabcsA) synthesis. Intercellular complementation could be detected between deltaagfA and deltaagfB strains only when both possessed the galE mutation. LPS O polysaccharide appears to be an impenetrable barrier to AgfA assembly between cells but not within individual cells. The presence of cellulose did not restrict Tafi formation between cells. Transmission electron microscopy of w+ S. enterica serovar Enteritidis 3b cells revealed diffuse Tafi networks without discernible fine structure. In the absence of cellulose, however, individual Tafi fibers were clearly visible, appeared to be occasionally branched, and showed the generally distinctive appearance described for Escherichia coli K-12 curli. A third extracellular matrix component closely associated with cellulose and Tafi was detected on Western blots by using immune serum raised to whole, purified Tafi aggregates. Cellulose was required to tightly link this material to cells. Antigenically similar material was also detected in S. enterica serovar Typhimurium and one diarrheagenic E. coli isolate. Preliminary analysis indicated that this material represented an anionic, extracellular polysaccharide that was distinct from colanic acid. Therefore, Tafi in their native state appear to exist as a complex with cellulose and at least one other component.

  17. Immunological characterization of recombinant Salmonella enterica serovar Typhi FliC protein expressed in Escherichia coli

    PubMed Central

    2012-01-01

    Like any other enteric pathogen, Salmonella also encounters acidic stress in the stomach as well as within the host macrophage milieu. However, the pathogen is reported to combat this stress through acid tolerance response (ATR), expressing a number of genes and eventually the proteins. Recently, an acid induced outer membrane phenotype encoded by fliC gene in Salmonella enterica serovar Typhi has been identified. In the present study, fliC gene was cloned to study its biological implications. The recombinant FliC (rFliC) protein was observed to stimulate the production of antibodies. These antibodies could also recognize the FliC protein (antigen) in the clinical samples i.e. blood samples from typhoid patents as well as healthy blood samples spiked with serovar Typhi. Moreover, the rFliC also reacted with the sera from patients suffering with typhoid fever indicating its in-vivo immunogenicity. Ex-vivo study revealed that rFliC has the potential to stimulate the macrophages to generate higher levels of inflammatory mediators such as malondialdehyde (MDA) and nitrite. The inflammatory potential of FliC was also confirmed in-vivo, by the paw oedema test as well as by flicking response of the inflamed paw indicating hyperalgesia occurring during inflammatory response. The findings of the present study indicate that acid induced FliC might be one of the factors enhancing the virulence of serovar Typhi under the host acidic conditions and may prove to be helpful in designing the prophylactic measures. PMID:23067582

  18. Genomic evidence reveals numerous Salmonella enterica serovar Newport reintroduction events in Suwannee watershed irrigation ponds.

    PubMed

    Li, Baoguang; Jackson, Scott A; Gangiredla, Jayanthi; Wang, Weimin; Liu, Huanli; Tall, Ben D; Beaubrun, Junia Jean-Gilles; Jay-Russell, Michele; Vellidis, George; Elkins, Christopher A

    2015-12-01

    Our previous work indicated a predominance (56.8%) of Salmonella enterica serovar Newport among isolates recovered from irrigation ponds used in produce farms over a 2-year period (B. Li et al., Appl Environ Microbiol 80:6355-6365, http://dx.doi.org/10.1128/AEM.02063-14). This observation provided a valuable set of metrics to explore an underaddressed issue of environmental survival of Salmonella by DNA microarray. Microarray analysis correctly identified all the isolates (n = 53) and differentiated the S. Newport isolates into two phylogenetic lineages (S. Newport II and S. Newport III). Serovar distribution analysis showed no instances where the same serovar was recovered from a pond for more than a month. Furthermore, during the study, numerous isolates with an indistinguishable genotype were recovered from different ponds as far as 180 km apart for time intervals as long as 2 years. Although isolates within either lineage were phylogenetically related as determined by microarray analysis, subtle genotypic differences were detected within the lineages, suggesting that isolates in either lineage could have come from several unique hosts. For example, strains in four different subgroups (A, B, C, and D) possessed an indistinguishable genotype within their subgroups as measured by gene differences, suggesting that strains in each subgroup shared a common host. Based on this comparative genomic evidence and the spatial and temporal factors, we speculated that the presence of Salmonella in the ponds was likely due to numerous punctuated reintroduction events associated with several different but common hosts in the environment. These findings may have implications for the development of strategies for efficient and safe irrigation to minimize the risk of Salmonella outbreaks associated with fresh produce.

  19. Epidemiology of a Salmonella enterica subsp. Enterica serovar Typhimurium strain associated with a songbird outbreak.

    USGS Publications Warehouse

    Blehert, David S.; Hernandez, Sonia M.; Keel, Kevin; Sanchez, Susan; Trees, Eija; ,

    2012-01-01

    Salmonella enterica subsp. enterica serovar Typhimurium is responsible for the majority of salmonellosis cases worldwide. This Salmonella serovar is also responsible for die-offs in songbird populations. In 2009, there was an S. Typhimurium epizootic reported in pine siskins in the eastern United States. At the time, there was also a human outbreak with this serovar that was associated with contaminated peanuts. As peanuts are also used in wild-bird food, it was hypothesized that the pine siskin epizootic was related to this human outbreak. A comparison of songbird and human S. Typhimurium pulsed-field gel electrophoresis (PFGE) patterns revealed that the epizootic was attributed not to the peanut-associated strain but, rather, to a songbird strain first characterized from an American goldfinch in 1998. This same S. Typhimurium strain (PFGE type A3) was also identified in the PulseNet USA database, accounting for 137 of 77,941 total S. Typhimurium PFGE entries. A second molecular typing method, multiple-locus variable-number tandem-repeat analysis (MLVA), confirmed that the same strain was responsible for the pine siskin epizootic in the eastern United States but was distinct from a genetically related strain isolated from pine siskins in Minnesota. The pine siskin A3 strain was first encountered in May 2008 in an American goldfinch and later in a northern cardinal at the start of the pine siskin epizootic. MLVA also confirmed the clonal nature of S. Typhimurium in songbirds and established that the pine siskin epizootic strain was unique to the finch family. For 2009, the distribution of PFGE type A3 in passerines and humans mirrored the highest population density of pine siskins for the East Coast.

  20. ramR mutations affecting fluoroquinolone susceptibility in epidemic multidrug-resistant Salmonella enterica serovar Kentucky ST198.

    PubMed

    Baucheron, Sylvie; Le Hello, Simon; Doublet, Benoît; Giraud, Etienne; Weill, François-Xavier; Cloeckaert, Axel

    2013-01-01

    A screening for non-target mutations affecting fluoroquinolone susceptibility was conducted in epidemic multidrug-resistant Salmonella enterica serovar Kentucky ST198. Among a panel of representative isolates (n = 27), covering the epidemic, only three showed distinct mutations in ramR resulting in enhanced expression of genes encoding the AcrAB-TolC efflux system and low increase in ciprofloxacin MIC. No mutations were detected in other regulatory regions of this efflux system. Ciprofloxacin resistance in serovar Kentucky ST198 is thus currently mainly due to multiple target gene mutations.

  1. Genomic Comparison of Non-Typhoidal Salmonella enterica Serovars Typhimurium, Enteritidis, Heidelberg, Hadar and Kentucky Isolates from Broiler Chickens

    PubMed Central

    Dhanani, Akhilesh S.; Block, Glenn; Dewar, Ken; Forgetta, Vincenzo; Topp, Edward; Beiko, Robert G.; Diarra, Moussa S.

    2015-01-01

    Background Non-typhoidal Salmonella enterica serovars, associated with different foods including poultry products, are important causes of bacterial gastroenteritis worldwide. The colonization of the chicken gut by S. enterica could result in the contamination of the environment and food chain. The aim of this study was to compare the genomes of 25 S. enterica serovars isolated from broiler chicken farms to assess their intra- and inter-genetic variability, with a focus on virulence and antibiotic resistance characteristics. Methodology/Principal Finding The genomes of 25 S. enterica isolates covering five serovars (ten Typhimurium including three monophasic 4,[5],12:i:, four Enteritidis, three Hadar, four Heidelberg and four Kentucky) were sequenced. Most serovars were clustered in strongly supported phylogenetic clades, except for isolates of serovar Enteritidis that were scattered throughout the tree. Plasmids of varying sizes were detected in several isolates independently of serovars. Genes associated with the IncF plasmid and the IncI1 plasmid were identified in twelve and four isolates, respectively, while genes associated with the IncQ plasmid were found in one isolate. The presence of numerous genes associated with Salmonella pathogenicity islands (SPIs) was also confirmed. Components of the type III and IV secretion systems (T3SS and T4SS) varied in different isolates, which could explain in part, differences of their pathogenicity in humans and/or persistence in broilers. Conserved clusters of genes in the T3SS were detected that could be used in designing effective strategies (diagnostic, vaccination or treatments) to combat Salmonella. Antibiotic resistance genes (CMY, aadA, ampC, florR, sul1, sulI, tetAB, and srtA) and class I integrons were detected in resistant isolates while all isolates carried multidrug efflux pump systems regardless of their antibiotic susceptibility profile. Conclusions/Significance This study showed that the predominant

  2. The complete genome sequence of Bacillus thuringiensis serovar Hailuosis YWC2-8.

    PubMed

    Zhu, Jun; Zhang, Qinbin; Cao, Ye; Li, Qiao; Zhu, Zizhong; Wang, Linxia; Li, Ping

    2016-02-10

    Bacillus thuringiensis, a typical aerobic, Gram-positive, spore-forming bacterium, is an important microbial insecticide widely used in the control of agricultural pests. B. thuringiensis serovar Hailuosis YWC2-8 with high insecticidal activity against Diptera and Lepidoptera insects has three insecticidal crystal protein genes, such as cry4Cb2, cry30Ea2, and cry56Aa1. In this study, the complete genome sequence of B. thuringiensis YWC2-8 was analyzed, which contains one circular gapless chromosome and six circular plasmids.

  3. Salmonella serovars and antimicrobial resistance in strains isolated from wild animals in captivity in Sinaloa, Mexico.

    PubMed

    Silva-Hidalgo, Gabriela; López-Valenzuela, Martin; Juárez-Barranco, Felipe; Montiel-Vázquez, Edith; Valenzuela-Sánchez, Beatriz

    2014-08-01

    The aim of the present study was to evaluate the frequency of antibiotic resistance in Salmonella spp. strains from wild animals in captivity at the Culiacan Zoo and the Mazatlan Aquarium in Sinaloa, Mexico. We identified 17 different Salmonella enterica serovars at a prevalence of 19.90% (Culiacan Zoo) and 6.25% (Mazatlan Aquarium). Antibiotic sensitivity tests revealed that, of the 83 strains studied, 100% were multidrug resistant (MDR). The drugs against which the greatest resistance was observed were: penicillin, erythromycin, dicloxacillin, ampicillin, cephalothin, and chloramphenicol. We therefore conclude that MDR is common among Salmonella isolates originating from wild animals in captivity in Sinaloa.

  4. Correlation of Phenotype with the Genotype of Egg-Contaminating Salmonella enterica Serovar Enteritidis

    PubMed Central

    Morales, Cesar A.; Porwollik, Steffen; Frye, Jonathan G.; Kinde, Hailu; McClelland, Michael; Guard-Bouldin, Jean

    2005-01-01

    The genotype of Salmonella enterica serovar Enteritidis was correlated with the phenotype using DNA-DNA microarray hybridization, ribotyping, and Phenotype MicroArray analysis to compare three strains that differed in colony morphology and phage type. No DNA hybridization differences were found between two phage type 13A (PT13A) strains that varied in biofilm formation; however, the ribotype patterns were different. Both PT13A strains had DNA sequences similar to that of bacteriophage Fels2, whereas the PT4 genome to which they were compared, as well as a PT4 field isolate, had a DNA sequence with some similarity to the bacteriophage ST64b sequence. Phenotype MicroArray analysis indicated that the two PT13A strains and the PT4 field isolate had similar respiratory activity profiles at 37°C. However, the wild-type S. enterica serovar Enteritidis PT13A strain grew significantly better in 20% more of the 1,920 conditions tested when it was assayed at 25°C than the biofilm-forming PT13A strain grew. Statistical analysis of the respiratory activity suggested that S. enterica serovar Enteritidis PT4 had a temperature-influenced dimorphic metabolism which at 25°C somewhat resembled the profile of the biofilm-forming PT13A strain and that at 37°C the metabolism was nearly identical to that of the wild-type PT13A strain. Although it is possible that lysogenic bacteriophage alter the balance of phage types on a farm either by lytic competition or by altering the metabolic processes of the host cell in subtle ways, the different physiologies of the S. enterica serovar Enteritidis strains correlated most closely with minor, rather than major, genomic changes. These results strongly suggest that the pandemic of egg-associated human salmonellosis that came into prominence in the 1980s is primarily an example of bacterial adaptive radiation that affects the safety of the food supply. PMID:16085829

  5. Pleural empyema due to Salmonella enterica serovar Enteritidis in an immunocompetent elderly patient: a case report

    PubMed Central

    Karachalios, Kostis; Siagris, Dimitrios; Lekkou, Alexandra; Anastassiou, Evangelos D.; Spiliopoulou, Iris; Gogos, Charalambos

    2016-01-01

    Introduction: Pleural empyema as a focal infection due to Salmonella enterica serovar Enteritidis is rare and most commonly described among immunosuppressed patients or patients who suffer from sickle cell anaemia and lung malignancies. Case presentation: Here, we present an 81-year-old immunocompetent Greek woman with bacteraemia and pleural empyema due to Salmonella Enteritidis without any gastrointestinal symptoms. Conclusion: In our case, we suggest that patient’s pleural effusion secondary to heart failure was complicated by empyema and that focal intravascular infection was the cause of bacteraemia. PMID:28348773

  6. Efficacy and safety of second-generation antipsychotic long-acting injections (SGA LAIs) in maintenance treatment of bipolar disorder: protocol for a systematic review and meta-analysis

    PubMed Central

    Prajapati, Asta R; Wilson, Jonathan

    2016-01-01

    Introduction Bipolar disorder requires long-term treatment but non-adherence is a common problem. Antipsychotic long-acting injections (LAIs) have been suggested to improve adherence but none are licensed in the UK for bipolar. However, the use of second-generation antipsychotics (SGA) LAIs in bipolar is not uncommon albeit there is a lack of systematic review in this area. This study aims to systematically review safety and efficacy of SGA LAIs in the maintenance treatment of bipolar disorder. Methods and analysis The protocol is based on Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) and will include only randomised controlled trials comparing SGA LAIs in bipolar. PubMed, EMBASE, CINAHL, Cochrane Library (CENTRAL), PsychINFO, LiLACS, http://www.clinicaltrials.gov will be searched, with no language restriction, from 2000 to January 2016 as first SGA LAIs came to the market after 2000. Manufacturers of SGA LAIs will also be contacted. Primary efficacy outcome is relapse rate or delayed time to relapse or reduction in hospitalisation and primary safety outcomes are drop-out rates, all-cause discontinuation and discontinuation due to adverse events. Qualitative reporting of evidence will be based on 21 items listed on standards for reporting qualitative research (SRQR) focusing on study quality (assessed using the Jadad score, allocation concealment and data analysis), risk of bias and effect size. Publication bias will be assessed using funnel plots. If sufficient data are available meta-analysis will be performed with primary effect size as relative risk presented with 95% CI. Sensitivity analysis, conditional on number of studies and sample size, will be carried out on manic versus depressive symptoms and monotherapy versus adjunctive therapy. Ethics and dissemination Ethical approval is not required as primary data will not be collected. The results will be disseminated through a peer-reviewed publication, conference presentation and

  7. lais de prise en charge des syndromes coronariens aigus avec sus-décalage du segment ST à Ouagadougou et facteurs associés à un allongement de ces délais: étude transversale à propos de 43 cas colligés au CHU-Yalgado Ouédraogo

    PubMed Central

    Yameogo, Nobila Valentin; Samadoulougou, André; Millogo, Georges; Kologo, Koudougou Jonas; Kombassere, Karim; Toguyeni, Boubacar Jean Yves; Zabsonre, Patrice

    2012-01-01

    La prise en charge de l'infarctus du myocarde est une course contre la montre et les trois premières heures constituent les « golden hours ». Les objectifs de ce travail étaient de déterminer le délai de prise en charge des infarctus du myocarde du myocarde au Burkina Faso, les facteurs liés à un allongement du délai et le pronostic des patients. Il s'agit d'une étude transversale descriptive menée de Septembre 2010 à Août 2011. Le critère d'inclusion était l'infarctus du myocarde dont le diagnostic était basé sur des critères clinique (douleur angineuse), électrocardiographique (sus-décalage persistant du segment ST dans au moins deux dérivations contiguës du même territoire coronaire, onde Q de nécrose) et biologique (élévation de la troponine). Les informations relatives au délai de prise en charge ont été recueillies: début du premier symptôme, contact avec le premier agent de santé et le cardiologue, nombre de centre de santé consulté avant le transfert en cardiologie, situation géographique des patients, moyen de transport utilisé. Les données ont été analysées grâce au logiciel SPSS version 17. Durant la période d’étude, 43 patients d’âge moyen de 56,51 ± 12,91 ans ont été admis pour infarctus du myocarde. Plus de la moitié des patients (72,0%) habitait Ouagadougou et sa banlieue. Le délai moyen entre le début de la douleur et la consultation dans la première structure sanitaire était de 48 ± 20,8 heures; celui entre le début de la douleur et la réalisation du premier ECG était en moyenne de 8,6 ±4,5 jours. Le délai entre la réalisation de l'ECG et l'admission dans le service de cardiologie était de 4,35 ±4,0 jours [00 heure et 13 jours]. Le délai entre l'admission dans le service de cardiologie et la thrombolyse était de 34 minutes. Enfin le délai entre le début de la douleur et le contact avec le cardiologue était de 9,6±3,5 jours. Il n'y avait pas de différence statiquement

  8. Studies on the presence and persistence of Pasteurella multocida serovars and genotypes in fowl cholera outbreaks.

    PubMed

    Singh, Reema; Blackall, Patrick J; Remington, Bruce; Turni, Conny

    2013-12-01

    Pasteurella multocida was isolated from poultry on six farms (one free-range duck farm, one free-range turkey farm, one conventional enclosed turkey farm, and three free-range layer farms) suffering fowl cholera outbreaks. In addition, historical isolates from previous outbreaks were available for the conventional turkey farm and the three free-range layer farms. The isolates were serotyped using the Heddleston scheme and genotyped using multi-locus sequencing typing. In the current outbreaks, two of the farms had two different sequence types (STs) of P. multocida in the investigated outbreak (the free-range turkey farm and one of the free-range layer farms). The remaining four farms had one ST within the investigated outbreak. In looking at the historical isolates, two of the four farms had multiple genotypes involved. On the four farms with historical isolates from previous outbreaks, at least one new genotype was present in the investigated outbreak as compared with the historical isolates. On one layer farm, one genotype persisted over a 10-year period. Serotyping revealed the presence of multiple serovars in the current and historical outbreaks, with serovars sometimes changing over time. This study has shown that several STs of P. multocida can be present during some outbreaks of fowl cholera, although other outbreaks involve a single ST. Also, the STs present on a property suffering repeated fowl cholera can both persist and change over time.

  9. Requirement for cobalamin by Salmonella enterica serovars Typhimurium, Pullorum, Gallinarum and Enteritidis during infection in chickens

    PubMed Central

    Vaz, Jacqueline Boldrin; Penha Filho, Rafael Antonio Casarin; Junior, Angelo Berchieri; Lemos, Manoel Victor Franco

    2011-01-01

    Salmonella enterica serovar Typhimurium synthesizes cobalamin (vitamin B12) only during anaerobiosis. Two percent of the S. Typhimurium genome is devoted to the synthesis and uptake of vitamin B12 and to B12-dependent reactions. To understand the requirement for cobalamin synthesis better, we constructed mutants of Salmonella serovars Enteritidis and Pullorum that are double-defective in cobalamin biosynthesis (ΔcobSΔcbiA). We compared the virulence of these mutants to that of their respective wild type strains and found no impairment in their ability to cause disease in chickens. We then assessed B12 production in these mutants and their respective wild type strains, as well as in S. Typhimurium ΔcobSΔcbiA, Salmonella Gallinarum ΔcobSΔcbiA, and their respective wild type strains. None of the mutants was able to produce detectable B12. B12 was detectable in S. Enteritidis, S. Pullorum and S. Typhimurium wild type strains but not in S. Gallinarum. In conclusion, the production of vitamin B12in vitro differed across the tested Salmonella serotypes and the deletion of the cbiA and cobS genes resulted in different levels of alteration in the host parasite interaction according to Salmonella serotype tested. PMID:24031771

  10. Interaction between Host Cells and Septicemic Salmonella enterica Serovar Typhimurium Isolates from Pigs ▿

    PubMed Central

    Bergeron, Nadia; Corriveau, Jonathan; Letellier, Ann; Daigle, France; Lessard, Louise; Quessy, Sylvain

    2009-01-01

    Salmonella enterica serovar Typhimurium is an important pathogen in swine and is also a frequently reported zoonotic agent. The objective of this study was to characterize isolates of S. enterica serovar Typhimurium associated with septicemia in swine and to compare them to isolates recovered from clinically healthy pigs. We were particularly interested in comparing the two groups of isolates for their ability to adhere to and invade host cells, to be phagocytized and survive in monocyte cells, to induce apoptosis, and to adhere to intestinal mucus. Their surface properties were also evaluated by interactions with solvents. The isolates recovered from diseased animals were shown to invade intestinal epithelial cell lines at a higher rate (P = 0.003) than isolates from healthy pigs. Septicemic isolates were phagocytized by human monocytes at a higher rate than isolates from healthy pigs (P = 0.009). The mean percentages of phagocytosis were significantly lower for human monocytes than for porcine monocytes (P = 0.02 and P = 0.008, respectively) for isolates from both diseased and healthy animals. Healthy animal isolates were phagocytized more by porcine monocytes at 15 min (P = 0.02) than septicemic isolates. No difference between isolates from septicemic pigs and isolates from healthy pigs was detected for other tested parameters. These results suggest that septicemic isolates have a particular pattern of invasion. PMID:19710281

  11. Cattle-derived Salmonella enterica serovar Dublin Infections in Red Foxes ( Vulpes vulpes ) in Tyrol, Austria.

    PubMed

    Glawischnig, Walter; Lazar, Judit; Wallner, Alice; Kornschober, Christian

    2017-01-31

    Salmonella enterica serovar Dublin is endemic in the cattle population in some areas of the Austrian province Tyrol, and each year single dairy farms have experienced clinical infections. To ascertain if Tyrolean red foxes ( Vulpes vulpes ) act as a reservoir for Salmonella spp., we tested hepatic tissue and intestinal content from foxes hunted in the years 2015-2016 by using microbiological methods. In addition, we included several fox fecal samples collected on a mountain pasture near chamois carcasses in the investigation. Of 434 foxes tested, nine animals (2.1%) were positive for Salmonella spp. Serotyping revealed five foxes positive with S. Dublin, demonstrating that this serovar exists in the Tyrolean fox population. The fecal samples collected in the area surrounding skeletonized chamois ( Rupicapra rupicapra ) also tested positive for S. Dublin. These chamois were probably victims of a waterborne outbreak caused by S. Dublin-shedding cattle. Our results indicate that the S. Dublin infections in red foxes were primarily acquired through ingestion of infected cattle material such as abortion tissues, but also by feeding on dead chamois. The findings underline the importance of interspecies transmission in this domestic/wildlife interface.

  12. Interaction of Salmonella enterica subspecies enterica serovar Typhimurium and mung bean (Phaseolus aureus) plants.

    PubMed

    Singh, Bhoj Raj; Chandra, Mudit; Agarwal, Ravikant

    2005-03-01

    The effect of Salmonella enterica subspecies enterica serovar Typhimurium, a zoonotic serovar, on mung bean (Phaseolus aureus) cultivar Pant Mung-3 plants was studied. Inoculation of mung bean seeds with Salmonella Typhimurium (7.2 x 10(5) CFU/ml) reduced sprouting rate (P < 0.07). This effect was more pronounced at higher levels of contamination. In the soil inoculated with Salmonella Typhimurium (7.2 x 10(6) CFU/g), germination was retarded and the number of defective sprouts was also significantly higher (P < 0.002). Salmonella Typhimurium grew inside germinating seeds and plant tissues and persisted in seedlings, adult plants, and harvested seedlings dried and stored at room temperature (30 degrees C) up to 45 days. Phaseolus aureus plants grown in sterile soil was resistant to Salmonella Typhimurium infection at 15 days of age and cleared Salmonella from all the aerial parts within 3 h of infection. However, Salmonella Typhimurium could be reisolated from the basal area of the stem and from soil even after 45 days of exposure to the pathogen.

  13. Hyperinvasiveness of Salmonella enterica serovar Choleraesuis linked to hyperexpression of type III secretion systems in vitro

    PubMed Central

    Huang, Kuan-Yeh; Wang, Yi-Hsin; Chien, Kun-Yi; Janapatla, Rajendra Prasad; Chiu, Cheng-Hsun

    2016-01-01

    Salmonella enterica serovars Choleraesuis and Typhimurium are among the non-typhoid Salmonella serovars that are important zoonotic pathogens. In clinical observation, S. Typhimurium typically causes diarrheal diseases; however, S. Choleraesuis shows high predilection to cause bacteremia. The mechanism why S. Choleraesuis is more invasive to humans remains unknown. In this study, we compared the S. Typhimurium LT2 and S. Choleraesuis SC-B67 proteomes through stable isotope labeling of amino acid in cell culture (SILAC). In SILAC, the expression of many virulence proteins in two type III secretion systems (T3SSs) were significantly higher in S. Choleraesuis than in S. Typhimurium. Similar differences were also found at the transcriptional level. Compared to S. Typhimurium, S. Choleraesuis showed a higher penetration level to Caco-2 (>100-fold) and MDCK (>10-fold) monolayers. In mice after oral challenge, the invasion of spleen and liver was also higher in S. Choleraesuis than in S. Typhimurium. The transcription of hilD in S. Choleraesuis was increased in physiological (1 mM) or high (10 mM) concentrations of Mg2+, but not in low (8 μM) concentration. We conclude that S. Choleraesuis showed hyperinvasiveness in cellular as well as mouse models due to hyperexpression of T3SS genes. PMID:27886215

  14. Salmonella enterica serovar Typhi impairs CD4 T cell responses by reducing antig