Differences in Cyst(e)ine Content between Vegetative Cells and Spores of Bacillus cereus and Bacillus megaterium

Abstract

IN the course of investigations on the role of sulphur amino-acids in the sporulation process of bacilli we studied the inhibitory effect of a large excess of cystine (10⁻⁴ M) on spore formation in Bacillus megaterium ¹, and the incorporation of cystine-³⁵S and methionine-³⁵S, added in small quantities to the nutrient medium before sporulation, into sporulating cells of inhibited and of control culture². The control culture, which was pre-adapted to cystine and treated with cystine just before sporulation, during sporulation incorporated considerable quantities of ³⁵S-amino-acids added at the time to the nutrient medium. During the ‘cystine inhibition’ the spore formation of B. megaterium remained for a long time in the first stage and the incorporation of labelled amino-acids was markedly lower.