Some problems of the ecology and taxonomy of marine microvibrios

The bactericidal effect of water from the Indian and Pacific oceans and Caspian and White seas on Escherichia coli was studied. It is shown that a decrease in the viability of E. coli cells is accompanied by the appearance and active multiplication of small bacteria of a vibrioid form. Two strains of such bacteria were isolated from a suspension of E. coli in seawater and purified from membranes of the substrate organism by the method of centrifugation in a Ficoll gradient. The marine bacteria of vibrioid form are very similar to the bacterial parasite Bdellovibrio bacteriovorus in fatty acid composition and characteristic cycle of development.