Autolysins and shape change in rodA mutants of Bacillus subtilis

The biochemical phenotype of rodA mutants was not affected by the simultaneous presence in double mutants of the lyt gene which makes them 90 to 95% deficient in autolysin action. The only morphological effect of this deficiency on the expression of the rod gene was that both the rod and the coccal forms of the mutant failed to separate and grew as long chains of cells. Inhibition of protein synthesis stopped the increase in peptidoglycan that occurred when the growth temperature for the mutants was raised to 45 degrees C. These observations support the idea that a derepression of peptidoglycan synthesis occurs at this temperature. The increased amount of cellular peptidoglycan at the higher growth temperature is not likely to be the result of the concomitant switching off of autolytic enzyme action.