Relationship of macromolecular synthesis to competence induction in a group H streptococcus

Abstract

Group H streptococcus strain Wicky, which was induced to competence for genetic transformation with competence factor (CF) derived from a related strain, displayed reduced rates of ribonucleic acid (RNA) and peptidoglycan synthesis. Pulse-labeling studies revealed that the inhibition of both RNA and peptidoglycan synthesis was maximal at the peak of competence and decreased as competence declined. These studies indicated that competence induction had only a slight effect on the rate of protein synthesis. Trypsin inactivation of CF prevented the reductions in synthesis normally elicited by CF preparations. If the addition of trypsin was delayed until 5 min after the addition of CF, competence induction and decreased synthesis of RNA and peptidoglycan were again apparent. Thus, the alterations in the synthesis of these macromolecules appeared to be related to the induction of competence. Further studies indicated that the apparent reductions in biosynthesis were not caused by decreased uptake of the labeled precursors by intact Wicky cells. In addition, these effects were probably not the result of turnover of macromolecules induced by CF. The lack of turnover of labeled peptidoglycan suggested that competence induction may not involve an autolysin.