Mutants of Bacillus subtilis Affected in Spore Outgrowth

Abstract
Six mutants of B. subtilis 168 that are temperature-sensitive in spore outgrowth were isolated. The outgrowth process proceeds normally at 35.degree. C, but at the non-permissive temperature (47.degree. C) it is arrested at a specific stage characteristic for each mutant strain. The mutants are not altered in vegetative growth whether at 35.degree. C or at 47.degree. C. They were characterized for their ability to synthesize RNA, proteins and DNA during outgrowth. A mutant defective in spore germination was also isolated; less than 5% of its spores can germinate at any of the temperatures tested. The mutations were mapped by transduction and transformation. The isolation of a number of outgrowth mutants which map at different loci and which affect outgrowth at different times is discussed in relation to the regulation of this process.