Analyse ultrastructurale et biochimique de mutants pléiotropes de Bacillus subtilis affectés dans le contrôle de la sporulation

Abstract

Derived from a Bacillus subtilis unstable mutant strains which hyperproduce extracellular proteases were found to contain mutations at loci scoC, scoD, or scoE; these were observed by transmission electron microscopy. In scoC and scoD strains, spores formed overproduced spore coat proteins and the spore ultrastructure was deeply altered. In scoE strains, stage III of the sporulation was blocked. The pleiotropic effect of scoC mutations was either positive or negative. In unstable strains, mutations at the scoC locus stimulated α-amylase and levane sucrase hyperproduction. In stable strains, the same mutations led to an absence of α-amylase synthesis but to a normal levane sucrase production. ScoD mutations only induced α-amylase hyperproduction, while scoE mutations allowed neither levane sucrase production nor spore coat protein synthesis.