Parasitic interaction of Bdellovibrio bacteriovorus with other bacteria.

Starr, Mortimer P. (University of California, Davis), and Nancy L. Baigent. Parasitic interaction of Bdellovibrio bacteriovorus with other bacteria. J. Bacteriol. 91:2006-2017. 1966.-The interactions of the predatory parasite, Bdellovibrio bacteriovorus, with Erwinia amylovora, Pseudomonas tabaci, and P. phaseolicola were examined by means of phase-contrast and electron microscopy. Attachment of the bdellovibrio to the host cell is apparently initially reversible; detachment occurs infrequently in the later stages. Formation of a pore in the host cell wall is followed by disorganization of the host nucleus and of the murein layer of the host cell wall. Short host cells become totally spheroplasted; the longer rods of Pseudomonas usually are partially spheroplasted. The parasite completely invades the host cell, and the cell contents of the host are digested. Bdellovibrios living as parasites inside the host increase considerably in size in comparison with those which have been living away from the host for a time. When the host protoplast is entirely lysed, the parasites leave the disintegrating "ghosted" cell envelope, and are ready to reinitiate the parasitic cycle. The time taken for a mature Bdellovibrio cell to complete the parasitic cycle may vary depending on the length of time the parasite has been away from its hosts.