Differentiation after premature release of intraperiplasmically growing Bdellovibrio bacteriovorous

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Abstract
B. bacteriovorus attacks and penetrates other gram-negative bacteria, creating a growth chamber termed a bdelloplast. Exposing the bdelloplasts to EDTA, followed by treatment with a lytic enzyme concentrate derived from bdellovibrio cultures, prematurely released the intraperiplasmically growing bdellovibrios at any time during their growth cycle. Upon release, the growth-form dbellovibrios terminated any initiated rounds of DNA synthesis and differentiated into motile attack-form cells. the ability of growth-form cells to synthesize DNA appears to depend upon an initiation signal that is not received until about 60 min after attack. Each subsequent round of DNA synthesis by the growing bdellovibrio filaments seems to require an additional initiation signal that is provided by their intraperiplasmic environment. Differentiation included fragmentation into multiple progeny cells to a degree proportional to the extent of intraperiplasmic growth. This differentiation could be performed totally at the expense of cellular reserves. The significance of these data to an understanding of the regulation of differentiation in bdellovibrios is discussed.