Chemotaxis between Vibrio cholerae O1 and a blue-green alga, Anabaena sp.

The chemotactic response of Vibrio cholerae O1 towards the mucilaginous sheath of Anabaena sp. was investigated by capillary tube method using a virulent strain of V. cholerae O1, El Tor, Ogawa (3083-T) and its isogenic mutant (HAP-1-T) that lacks the hap gene, which codes for mucinase (HA/protease). Homogenates of Anabaena sp. and purified mucin were used in this study as chemoattractants. Results showed 5·7% bacterial accumulation of wild-type V. cholerae O1 towards 4% homogenates of Anabaena sp. whereas, its mutant (hap - ) showed 2·9% accumulation after 90 min. The higher percentage of attraction of wild-type V. cholerae O1 than the mutant (hap - ) towards mucin and the homogenates of Anabaena sp. might be due to the activity of mucinase. These results indicate the role of mucinase in the chemotactic motility of V. cholerae O1 towards Anabaena sp.