Rapid, chloramphenicol-resistant, activation of membrane electron transport on germination of Bacillus spores

Abstract

KEILIN1 observed that the life cycle of diverse organisms includes a stage when life seems to be arrested, which he termed the cryptobiotic state. As an example of this, the mature bacterial spore can remain dormant with no detectable metabolism for long periods and then on exposure to germinants, rapidly germinate and outgrow in a synchronous manner, to yield a vegetative cell. We have been particularly interested in the composition and activities of the membrane-bound electron transport chain in sporulating Bacillus megaterium KM (ref. 2) and in the unique reversed orientation which characterises the membranes surrounding the developing spore3. This report describes the rapid changes observed in the membrane of Bacillus megaterium KM spores during germination and outgrowth. A rapid chloramphenicol-resistant, activation of membrane NADH oxidase activity occurred within 5–10 min of germination. Membrane-bound DL-α-glycerol-P and L-malate oxidase activities appeared sequentially at later times and their appearance was prevented by chloramphenicol. Evidence is presented to suggest that in the dormant spore the electron transport sequence is blocked in the region between NADH dehydrogenase and the cytochromes.