Sporangila autolysis in Clostridium perfringens type A

The autolytic system functioning in the release of mature spores and enterotoxin from sporangia of Clostridium prefringens was partially characterized. After sporangial autolysis in buffer, the supernatant fluid of the suspension contained autolysin active against purified sporangial walls. The autolysin was most active at pH 8 and 37°C, in the presence of Co²⁺ (0.3 · 10⁻³ M CoCl₂) and trypsin (48 μg/ml). Sodium dodecyl sulfate-treated sporangial walls further extracted with trichloroacetic acid to remove teichoic acid were a better enzyme substrate than walls treated only with sodium dodecyl sulfate. N-Acetylmuramyl-l-alanine amidase activity which released N-terminal alanine, and endopeptidase activity which hydrolysed the d-alanyl-glycine linkage liberating N-terminal glycine and C-terminal alanine, were both functional at pH 8. It is not known if one or two enzyme are involved. Autolysin appeared in cells as early as 2 h after inoculation into sporulation medium. Two asporogenic Stage 0 mutants grown in sporulation medium also produced autolysin identical in mode of action to that of the sporogenic wild type. Although the active cellular autolysin concentration subsequently decreased as cells sporilated, the walls of 8-h-old sporangia containing refractile heat-resistant spores were more susceptible to digestion by autolysin, than those of 2-, 4-, or 6-h-old cells grown in sporulation medium or of 4- or 14-h vegetative cells from growth medium. The results suggest that a progressive change may occur in the structure of the sporangial wall during spore morphogenesis, thus increasing its susceptibility to autolysis.