On Substrate-accelerated Death in Klebsiella aerogenes

Abstract

SUMMARY Glycerol-accelerated death of starved, glycerol-limited populations of Klebsiella aerogenes occurred if the medium used to assess viability contained glycerol, but not if it contained pyruvate or glucose. Pyruvate-accelerated death of glycerol-limited populations occurred with all three types of recovery medium. Lactose-limited populations showed lactose-accelerated death, with comparable substrate and recovery medium specificity, without change in β-galactosidase content. Inducers of the lac operon, whether gratuitous or not, also accelerated death of lactose-limited populations. Cyclic AMP (0·08 mm) or its butyryl derivative (0·02 mm), but not a variety of other nucleotides, prevented substrate-accelerated death but did not abolish the prolonged lags characteristic of survivors of this stress; these findings further support the view that substrate-accelerated death is related to intracellular repression-derepression processes.