Dynamics of Formation and Characteristics of Ultrastructural Organization of Bdelloplasts Conglomerates of Bacteria of the Genus Bdellovibrio

The structure of bdelloplasts conglomerates formed during interactions between Bdellovibrio and prey bacterial cells within 24 h of incubation in response to a decrease in prey cell concentration to 106–107 cells/mL was studied. It was shown that the onset of extracellular polysaccharide accumulation in the medium during interactions between the predator and prey bacterial cells correlated with the onset of bdelloplasts conglomerate formation. The bdelloplasts conglomerate, at the final stage of its formation, exhibits the features of a dormant multicellular form and is organized as a “collective” cyst, which includes a “core” consisting of a cluster of bdelloplasts embedded in a vesicular–fibrillar matrix, and a common double envelope (intine and exine). In the dormant state of the “collective” cyst, Bdellovibrio can survive unfavorable conditions for a long time.