Influence of Alkali Metal Cations on the Germination of Spores of Wild-type and gerD Mutants of Bacillus subtilis

Abstract

Summary: Spores of gerD mutants of Bacillus subtilis prepared on a rich medium were defective in their germination responses to L-alanine, to a mixture of l-asparagine, d-glucose, d-fructose and KC1 (AGFK), and to Penassay broth. They showed an increased response and sensitivity to L-alanine when monovalent cations were also present. When prepared by a resuspension method, the spores had an improved germination response to L-alanine, even in the absence of these cations, but showed no such improvement in response to AGFK. No gross differences were found between wild-type and gerD spores in heat or chemical resistance, dipicolinic acid level or morphology. It is proposed that an alternative pathway of germination involving monovalent cations exists in both wild-type and gerD spores.