Anaerobic growth promotes synthesis of colonization factors encoded at the Vibrio pathogenicity island in Vibrio cholerae El Tor.

Pathogenesis of the facultative anaerobe Vibrio cholerae takes place at the gut under low oxygen concentrations. To identify proteins which change their expression level in response to oxygen availability, proteomes of V. cholerae El Tor C7258 grown in aerobiosis, microaerobiosis and anaerobiosis were compared by two-dimensional electrophoresis. Twenty-six differentially expressed proteins were identified which are involved in several processes including iron acquisition, alanine metabolism, purine synthesis, energy metabolism and stress response. Moreover, two proteins implicated in exopolysaccharide synthesis and biofilm formation were produced at higher levels under microaerobiosis and anaerobiosis, which suggests a role of oxygen deprivation in biofilm development in V. cholerae. In addition, six proteins encoded at the Vibrio pathogenicity island attained the highest expression levels under anaerobiosis, and five of them are required for colonization: three correspond to toxin-coregulated pilus biogenesis components, one to soluble colonization factor TcpF and one to accessory colonization factor A. Thus, anaerobiosis promotes synthesis of colonization factors in V. cholerae El Tor, suggesting that it may be a key in vivo signal for early stages of the pathogenic process of V. cholerae.