Abstract
In the aquatic environment, chemotaxis is one of the most important mechanisms of association between bacteria and other living biota. To investigate the mechanism of the chemotactic movement of Vibrio cholerae 0139 toward blue-green algae (BGA), the homogenates of four BGA species, Anabaena spp., A. variabilis, Nostoc spp. and Hapalosiphon spp., were examined by chemotaxis capillary assay. The assay revealed that V. cholerae 0139 swims toward the BGA with the highest chemotactic response observed in a 4% solution of Anabaena spp. homogenate. The components of the mucilaginous sheath involved in this chemotactic response were examined. Major components were tested in a chemotaxis assay to determine the attractants present. A number of mucilaginous sheath-associated compounds, in particular free amino acids and carbohydrates, acted as chemoattractants for V. cholerae 0139. Importantly, only when these attractants were combined into a single mixture were levels of chemotactic activity similar to those of Anabaena spp. It was revealed that 25°C and 1.7% salinity favored the chemotactic motility toward the homogenates of BGA. V. cholerae 01 was also attracted to homogenates of Anabaena spp.
