Role of polyphosphate kinase gene (ppk) for survival of Vibrio cholerae O1 in surface water of Bangladesh

Polyphosphate provides a substitute for ATP and energy source when phosphorus is a limiting resource in nature. The present study focuses on the role ofpolyphosphate for the survival of Vibrio cholerae in the aquatic habitats as an autochthonous bacterium. The survival advantages of polyphosphate of V. cholerae O1 having (wild type) and lacking (mutant) polyphosphate kinase (ppk) gene in surface water and with Anabaena variabilis were compared by cultural, Direct Fluorescent Antibody (DFA) and polymerase chain reaction methods in natural water microcosms. The microcosm's water was prepared by filtering and physicochemical parameters were also investigated by standard methods. The results revealed that both fresh and saline water, the wild type strain enhanced survival in cultural conditioned than ppk mutant strain. However, Fluorescent Antibody Direct Viable Counts (FADVC) and Polymerase Chain Reaction (PCR) results noted both strains have the equal survival strategy in viable but nonculturable state (VNC). In conclusion, it could be hypothesized that the polyphosphate inclusion body might keep cultivable and survivable at low phosphate natural environment of the aquatic bacterium.