{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,5,14]],"date-time":"2025-05-14T00:10:49Z","timestamp":1747181449683,"version":"3.40.5"},"reference-count":65,"publisher":"Microbiology Society","issue":"2","funder":[{"DOI":"10.13039\/501100012339","name":"CSIR \u2013 Indian Institute of Chemical Biology","doi-asserted-by":"crossref","award":["MLP118"],"award-info":[{"award-number":["MLP118"]}],"id":[{"id":"10.13039\/501100012339","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2022,2,3]]},"abstract":"<jats:p><jats:italic><jats:named-content content-type=\"species\"><jats:ext-link xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" ext-link-type=\"uri\" xlink:href=\"http:\/\/doi.org\/10.1601\/nm.2947\" xlink:type=\"simple\">Vibrio cholerae<\/jats:ext-link><\/jats:named-content><\/jats:italic>O1 and O139 isolates deploy cholera toxin (CT) and toxin-coregulated pilus (TCP) to cause the diarrhoeal disease cholera. The<jats:italic>ctxAB<\/jats:italic>and<jats:italic>tcpA<\/jats:italic>genes encoding CT and TCP are part of two acquired genetic elements, the CTX phage and<jats:italic><jats:named-content content-type=\"genus\"><jats:ext-link xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" ext-link-type=\"uri\" xlink:href=\"http:\/\/doi.org\/10.1601\/nm.2946\" xlink:type=\"simple\">Vibrio<\/jats:ext-link><\/jats:named-content><\/jats:italic>pathogenicity island-1 (VPI-1), respectively. ToxR and ToxT proteins are the key regulators of virulence genes of<jats:italic><jats:named-content content-type=\"species\"><jats:ext-link xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" ext-link-type=\"uri\" xlink:href=\"http:\/\/doi.org\/10.1601\/nm.2947\" xlink:type=\"simple\">V. cholerae<\/jats:ext-link><\/jats:named-content><\/jats:italic>O1 and O139.<jats:italic><jats:named-content content-type=\"species\"><jats:ext-link xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" ext-link-type=\"uri\" xlink:href=\"http:\/\/doi.org\/10.1601\/nm.2947\" xlink:type=\"simple\">V. cholerae<\/jats:ext-link><\/jats:named-content><\/jats:italic>isolates belonging to serogroups other than O1\/O139, called non-O1\/non-O139, are usually devoid of virulence-related elements and are non-pathogenic. Here, we have analysed the available whole genome sequence of an environmental toxigenic<jats:italic><jats:named-content content-type=\"species\"><jats:ext-link xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" ext-link-type=\"uri\" xlink:href=\"http:\/\/doi.org\/10.1601\/nm.2947\" xlink:type=\"simple\">V. cholerae<\/jats:ext-link><\/jats:named-content><\/jats:italic>non-O1\/non-O139 strain, VCE232, carrying the CTX phage and VPI-1. Extensive bioinformatics and phylogenetic analyses indicated high similarity of the VCE232 genome sequence with the genome of<jats:italic><jats:named-content content-type=\"species\"><jats:ext-link xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" ext-link-type=\"uri\" xlink:href=\"http:\/\/doi.org\/10.1601\/nm.2947\" xlink:type=\"simple\">V. cholerae<\/jats:ext-link><\/jats:named-content><\/jats:italic>O1 strains, including organization of the VPI-1 locus,<jats:italic>ctxAB, tcpA<\/jats:italic>and<jats:italic>toxT<\/jats:italic>genes, and promoters. We established that the VCE232 strain produces an optimal amount of CT at 30\u2009\u00b0C under AKI conditions. To investigate the role of ToxT and ToxR in the regulation of virulence factors, we constructed \u0394<jats:italic>toxT<\/jats:italic>, \u0394<jats:italic>toxR<\/jats:italic>and \u0394<jats:italic>toxT<\/jats:italic>\u0394<jats:italic>toxR<\/jats:italic>deletion mutants of VCE232. Extensive genetic analyses of these mutants indicated that the<jats:italic>toxT<\/jats:italic>and<jats:italic>toxR<\/jats:italic>genes of VCE232 are crucial for CT and TCP production. However, unlike O1 isolates, the presence of either<jats:italic>toxT<\/jats:italic>or<jats:italic>toxR<\/jats:italic>gene is sufficient for optimal CT production in VCE232. In addition, the VCE232 \u0394<jats:italic>toxR<\/jats:italic>mutant showed differential regulation of the major outer membrane proteins, OmpT and OmpU. This is the first attempt to explore the regulation of expression of major virulence genes and regulators in an environmental toxigenic<jats:italic><jats:named-content content-type=\"species\"><jats:ext-link xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" ext-link-type=\"uri\" xlink:href=\"http:\/\/doi.org\/10.1601\/nm.2947\" xlink:type=\"simple\">V. cholerae<\/jats:ext-link><\/jats:named-content><\/jats:italic>non-O1\/non-O139 strain.<\/jats:p>","DOI":"10.1099\/mic.0.001135","type":"journal-article","created":{"date-parts":[[2022,2,3]],"date-time":"2022-02-03T21:16:38Z","timestamp":1643922998000},"source":"Crossref","is-referenced-by-count":2,"title":["Genetic and mutational analysis of virulence traits and their modulation in an environmental toxigenic Vibrio cholerae non-O1\/non-O139 strain, VCE232"],"prefix":"10.1099","volume":"168","author":[{"given":"Quoelee","family":"Biswas","sequence":"first","affiliation":[{"name":"Infectious Diseases and Immunology Division, CSIR \u2013 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India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Diganta","family":"Maiti","sequence":"additional","affiliation":[{"name":"Infectious Diseases and Immunology Division, CSIR \u2013 Indian Institute of Chemical Biology, Kolkata 700 032, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2447-5380","authenticated-orcid":false,"given":"Bhabatosh","family":"Das","sequence":"additional","affiliation":[{"name":"Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad 121 001, India"},{"name":"School of Life Sciences, Manipal Academy of Higher Education, Manipal 576 104, Karnataka, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Rupak K.","family":"Bhadra","sequence":"additional","affiliation":[{"name":"Infectious Diseases and Immunology Division, CSIR \u2013 Indian Institute of Chemical Biology, Kolkata 700 032, 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