Mechanisms of Cholera Agent Persistence under Varying Osmolarity Conditions

Abstract

During the lifecycle cholera agent, being human pathogen and natural reservoir inhabitant, is constantly exposed to varying osmolarity environments, induced by different sodium chloride content. However, Vibrio cholerae has created the mechanisms providingfor adaptation to changes of living surroundings. The review covers the data on the impact of NaCl on the survivability of toxigenic V. cholerae strains, and information on mechanisms of adaptation to varying osmolarity. It is demonstrated that at low NaCl contents expression of genes, necessary for cell wall formation and cell growth is elevated; under high NaCl concentration conditions for transcription of genes, encoding transport systems, removing sodium ions, and also responsible for biosynthesis of osmoprotectors, are increased. There is discussed the role of two transcription regulators, CosR and OscR, cooperatively altering gene expression in accordance with particular environmental osmolarity. Further studies into the mechanisms of V. cholerae adaptation to changes of sodium chloride concentration will extend the knowledge about biology and ecology of the pathogen.