Early events in development of streptococcal competence

Area of Science:

• Microbiology
• Molecular Biology
• Bacterial Genetics

Background:

• Group H streptococci develop competence for genetic transformation.
• Competence factor (CF) is essential for this process.
• The precise role of CF and its binding in competence development remains incompletely understood.

Purpose of the Study:

• To delineate the early biochemical events in competence development in group H streptococci.
• To characterize the roles of free and cell-bound competence factor (CF) in inducing competence.
• To investigate the requirement of protein synthesis for competence induction.

Main Methods:

• Utilized trypsin to inactivate competence factor (CF) and chloramphenicol to inhibit protein synthesis.
• Separated and characterized early events in competence development.
• Measured cell-bound CF (CB-CF) accumulation and transformation efficiency.

Main Results:

• Identified three distinct steps in competence development: CF production/release, CF adsorption, and competence induction.
• Demonstrated that free CF is rapidly adsorbed by producing cells, forming trypsin-insensitive cell-bound CF (CB-CF).
• Showed that only trypsin-insensitive CB-CF effectively induces competence, and this process requires protein synthesis.

Conclusions:

• Competence development in group H streptococci involves sequential steps of CF production, adsorption, and induction.
• Trypsin-insensitive cell-bound CF is the critical inducer of competence.
• Protein synthesis is essential for all stages of competence development.