ISSN 2736-1756
Advanced Journal of Microbiology Research ISSN 2241-9837 Vol. 13 (2), pp. 001-010, February, 2019. © International Scholars Journals
Full Length Research Paper
Virulence gene expression, proteins secreted and morphological alterations of Vibrio parahaemolyticus and Vibrio alginolyticus in response to long-term starvation in seawater
Fethi Ben Abdallah1,2*, Ali Ellafi1, Rihab Lagha1, Héla Kallel2 and Amina Bakhrouf1
1Laboratoire d’Analyse, Traitement et Valorisation des Polluants de l’Environnement et des Produits, Faculté de Pharmacie Rue Avicenne, Monastir 5000, Tunisie.
2Unité de Fermentation et de Développement de Vaccins Virologiques, Institut Pasteur de Tunis, 13 Place Pasteur, 1002, Tunisie.
Accepted 09 January, 2019
Abstract
In this study, we incubated Vibrio parahaemolyticus and Vibrio alginolyticus (marine food-borne pathogens bacteria) in seawater for 8 months to study their morphologic, proteomic and genetic responses to starvation. The atomic force micrographs of stressed strains showed a reduction of the cells size and an evolution to two coccoid-shape forms whose length is less than 0.4 m and between 0.5 and 1 m. Extracellular protein patterns and gelatinase profiles of stressed bacteria were also altered. Indeed, these modifications were manifested by the appearance and/or disappearance of bands as well as in the level of expression of certain proteins. In addition, we also searched for the presence of eight Vibrio cholerae virulence genes: toxR, toxS, toxRS, ctxA, zot, ace, toxT, and Virulence Pathogenicity Island (VPI) in the genome of investigated strains. The expression level of VPI gene studied by reverse transcriptase polymerase chain reaction was decreased, whereas the mRNA quantities of toxR, toxS, and ace in starved Vibrio remained stable.
Key words: Vibrio, seawater, alterations, morphology, proteins secreted, virulence gene expression, RT-PCR.