The Experts below are selected from a list of 9393 Experts worldwide ranked by ideXlab platform
A.n. Ghosh - One of the best experts on this subject based on the ideXlab platform.
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Characterization of Vibrio Cholerae O1 ElTor typing phage S5
Archives of Virology, 2007Co-Authors: K. Mitra, A.n. GhoshAbstract:S5 (ATCC No. 51352-B2), a Vibrio Cholerae O1 ElTor typing phage was characterized. The growth characteristics and inactivation kinetics (thermal, UV and pH) of this lytic phage were investigated. Phage morphology was examined by electron microscopy and was classified as belonging to the family Podoviridae . The S5 phage genome is shown to be a linear double-stranded 39-kb-long DNA as determined by electron microscopy and restriction digestion. Partial denaturation maps were constructed and were used to show that the DNA is non-permuted and terminally redundant. The replication origin of this T7-like phage was visualized by electron microscopy. The polarity of packaging of S5 DNA in the phage head was determined. SDS-PAGE of phage S5 shows two major structural polypeptides of 50 and 42 kDa. A 3D structure of the phage head was reconstructed at a resolution of 37 Å using Cryo-EM and a single-particle reconstruction technique.
Afsar Ali - One of the best experts on this subject based on the ideXlab platform.
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monitoring water sources for environmental reservoirs of toxigenic Vibrio Cholerae O1 haiti
Emerging Infectious Diseases, 2014Co-Authors: Meer T Alam, Thomas A Weppelmann, Chad D Weber, Judith Johnson, Mohammad H Rashid, Catherine S Birch, Babette A Brumback, Valery Madsen Beau De Rochars, J Glenn, Afsar AliAbstract:An epidemic of cholera infections was documented in Haiti for the first time in more than 100 years during October 2010. Cases have continued to occur, raising the question of whether the microorganism has established environmental reservoirs in Haiti. We monitored 14 environmental sites near the towns of Gressier and Leogane during April 2012–March 2013. Toxigenic Vibrio Cholerae O1 El Tor biotype strains were isolated from 3 (1.7%) of 179 water samples; nontoxigenic O1 V. Cholerae was isolated from an additional 3 samples. All samples containing V. Cholerae O1 also contained non-O1 V. Cholerae. V. Cholerae O1 was isolated only when water temperatures were ≥31°C. Our data substantiate the presence of toxigenic V. Cholerae O1 in the aquatic environment in Haiti. These isolations may reflect establishment of long-term environmental reservoirs in Haiti, which may complicate eradication of cholera from this coastal country.
Siriporn Chantaroj - One of the best experts on this subject based on the ideXlab platform.
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Phylogenetic analysis revealed the dissemination of closely related epidemic Vibrio Cholerae O1 isolates in Laos, Thailand, and Vietnam
Open Forum Infectious Diseases, 2020Co-Authors: Masatomo Morita, Kazuhisa Okada, Tetsu Yamashiro, Tsuyoshi Sekizuka, Amonrattana Roobthaisong, Warawan Wongboot, Siriporn Chantaroj, Phonepadith Xangsayarath, Noikaseumsy SithivongAbstract:Abstract We performed whole-genome sequencing of Vibrio Cholerae O1 isolates from Laos, Thailand, and Vietnam, where cholera outbreaks occurred, to determine their genetic lineages. Core genome phylogenetic analysis revealed that the isolates located in same lineage without regional clusters, which suggests that closely related strains circulated in Southeast Asia.
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genotypic and pfge mlva analyses of Vibrio Cholerae O1 geographical spread and temporal changes during the 2007 2010 cholera outbreaks in thailand
PLOS ONE, 2012Co-Authors: Kazuhisa Okada, Amonrattana Roobthaisong, Ichiro Nakagawa, Shigeyuki Hamada, Siriporn ChantarojAbstract:Background Vibrio Cholerae O1 El Tor dominated the seventh cholera pandemic which occurred in the 1960s. For two decades, variants of V. Cholerae O1 El Tor that produce classical cholera toxin have emerged and spread globally, replacing the prototypic El Tor biotype. This study aims to characterize V. Cholerae O1 isolates from outbreaks in Thailand with special reference to genotypic variations over time.
K. Mitra - One of the best experts on this subject based on the ideXlab platform.
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Characterization of Vibrio Cholerae O1 ElTor typing phage S5
Archives of Virology, 2007Co-Authors: K. Mitra, A.n. GhoshAbstract:S5 (ATCC No. 51352-B2), a Vibrio Cholerae O1 ElTor typing phage was characterized. The growth characteristics and inactivation kinetics (thermal, UV and pH) of this lytic phage were investigated. Phage morphology was examined by electron microscopy and was classified as belonging to the family Podoviridae . The S5 phage genome is shown to be a linear double-stranded 39-kb-long DNA as determined by electron microscopy and restriction digestion. Partial denaturation maps were constructed and were used to show that the DNA is non-permuted and terminally redundant. The replication origin of this T7-like phage was visualized by electron microscopy. The polarity of packaging of S5 DNA in the phage head was determined. SDS-PAGE of phage S5 shows two major structural polypeptides of 50 and 42 kDa. A 3D structure of the phage head was reconstructed at a resolution of 37 Å using Cryo-EM and a single-particle reconstruction technique.
Masahiko Ehara - One of the best experts on this subject based on the ideXlab platform.
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Pili of Vibrio Cholerae O1 Biotype El Tor: A Comparative Study on Adhesive and Non-Adhesive Strains
Microbiology and Immunology, 2013Co-Authors: M Iwanaga, Noboru Nakasone, Masahiko EharaAbstract:Pili were found on the cell surface of non-adhesive Vibrio Cholerae O1 Biotype E1 Tor as well as the adhesive strain. Purified pili of the adhesive and non-adhesive strains were morphologically, electrophoretically, and immunologically, indistinguishable from each other. The molecular weights of both pilin (subunit protein of the pilus) were about 16,000 daltons as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. These 16 kDa pili are different from the pilus colonization factor, which is a 20.5 kDa protein, reported by Taylor et al. The 16 kDa pili of Vibrio Cholerae O1 Biotype E1 Tor have hemagglutinating activity, but may have no role in colonization, because non-adhesive strains also have such pili.
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Filamentous Phages of Vibrio Cholerae O1 and O139
Epidemiological and Molecular Aspects on Cholera, 2010Co-Authors: Masahiko Ehara, M. John AlbertAbstract:Bacteriophages are abundant biological entities and they play an enormous role in the adaptive evolution of bacteria. Vibrio Cholerae O1 and O139 strains produce several types of spheroidal phages and filamentous phages, which are known to have genes encoding several virulence factors. Filamentous phages of V. Cholerae O1 and O139 were classified into two types: fs1 and fs2. The fs1 has several subtypes and presumably play a great role in several epidemics. The receptor for filamentous phages fs1 and fs2 was shown to be the type IV fimbriae. Production of fimbriae was repressed even in the fimbriate strains due to infection with filamentous phages and this was confirmed using animal models. This chapter also describes background information regarding the development of effective cholera vaccine using phase variation in V. Cholerae.
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Two different mechanisms of ampicillin resistance operating in strains of Vibrio Cholerae O1 independent of resistance genes
Fems Microbiology Letters, 2009Co-Authors: Dong Tu Nguyen, Tuan Cuong Ngo, Huy Hoang Tran, Thi Phuong Lan Nguyen, Binh Minh Nguyen, Kouichi Morita, Masahiko EharaAbstract:Autoagglutinable strains of Vibrio Cholerae O1 (seven nonfimbriate strains and one fimbriate strain) were transformed to obtain resistance to ampicillin. Two distinct mechanisms were found in these strains. One was operating in nonfimbriate strains by reducing OmpU protein production and the other was operating in a fimbriate strain (Bgd17) by newly overproducing cpxP protein. The twitching motility in the fimbriate Bgd17 strain disappeared depending on the production of cpxP protein, suggesting that fimbriation of V. Cholerae O1 is controlled by a two-component signal transduction system.
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Drug susceptibility and its genetic basis in epidemic Vibrio Cholerae O1 in Vietnam.
Epidemiology and Infection, 2004Co-Authors: Masahiko Ehara, B. M. Nguyen, D. T. Nguyen, Claudia Toma, Naomi Higa, M IwanagaAbstract:The drug susceptibility and genes responsible for the drug resistance of Vibrio Cholerae O1 isolated in Vietnam in 1995, 2000 and 2002 were studied. The strains isolated in 1995 were resistant to streptomycin and harboured the class I integron which contained the aadA1 gene responsible for streptomycin resistance. The strains isolated in 2000 were devoid of a class I integron but were multiple-drug resistant and harboured SXT constin, with several drug-resistant genes. The genes responsible for streptomycin resistance were strA and strB. The strains isolated in 2002 were sensitive to all drugs examined, and the organisms were devoid of both class I integron and SXT constin. Cholera outbreaks in the three periods examined (1995, 2000 and 2002) were apparently due to different categories of V. Cholerae O1.
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Development of hyperfimbriated strains of Vibrio Cholerae O1.
Microbiology and Immunology, 2000Co-Authors: Masahiko Ehara, Yoshio Ichinose, Mamoru Iwami, Toshiya HirayamaAbstract:The Vibrio Cholerae O1 and O139 fimbrillin genes (fimA or mshA) were amplified by polymerase chain reaction and cloned into an Escherichia coli pCR™ vector. These clones were sequenced. The fimA sequences were found to be identical between V. Cholerae O1 and O139. One of the plasmids was digested with EcoR I and inserted into the EcoR I site of pGEX-3X. The plasmid pVPP thus obtained was transferred into strains of wild-type V. Cholerae O1 Bgd17 (classical in biotype) and its fimbriated strain by electroporation. The recombinant plasmid pVPP overexpressed mature fimbriae following induction of the tac promoter with isopropyl-beta-d-thiogalactopyranoside. The cloned gene product was purified to homogeneity by sucrose-linear gradient centrifugation (7.8 mg of fimbriae/L-culture). All the properties of the recombinant fimbriae (e.g., subunit structure, hydrophobicity, hemagglutinating activity sensitive to d-mannose and d-glucose and immunogenicity) were identical to those of the wild-type fimbriae. This overexpression system will be extremely useful for rapid, inexpensive preparation of large amounts of fimbriae for vaccine design and development.
