[Use of rifampicin for directed modification of the nucleotide composition of the cells of Bacillus megaterium and Candida utilis].

The object of this work was to study the effect of rifampicin on the physiological state of Bacillus megaterium and Candida utilis in chemostat and batch cultures. When B. megaterium is cultivated in a medium containing 1 microgram of rifampicin per litre, its metabolism changes, the pool of free nucleotides rises, and the content of RNA drops in response to the specific action of the inhibitor. The modified state is observed throughout many generations. The action of the inhibitor is also non-specific: protein content falls and polyhydroxybutyric acid is accumulated. The morphology of B. megaterium cells changes: they become larger, their cell wall thickens, and the separation of cells from one another is complicated. At a high concentration (5 mg/l), rifampicin decelerates the growth of C. utilis and causes merely a minor non-specific inhibition.