| 2244 A gene mutation in Streptococcus mutans that exhibit a pleiotropic effect on mutacin production, cell division and coaggregation | ||
|
F. QI, UCLA, Los Angeles, CA, USA, P. CHEN, University of Alabama at Birmingham, USA, P.W. CAUFIELD, University of Alabama at Birmingham School of Dentistry, USA, and W. SHI, UCLA School of Dentistry, Los Angeles, USA Objective: The objective of this study is to uncover trans-acting regulators for mutacin production and determine the relationship between mutacin production and stress response, quorum sensing and biofilm formation in S. mutans. Methods: functional genomics, insertional inactivation, and physiological methods were utilized. Results: By searching the genome database of S. mutans, we found a homolog of the mecB gene. MecB is also called ClpC, which is a member of the Clp ATPase family that exist in both prokaryotic and eukaryotic cells, and plays a vital role during stress response. The ClpC system in B. subtilis and S. pneumoniae regulates the development of competence, cell division, and stress response. The mecB gene in S. mutans was inactivated by antibiotic cassette insertional inactivation and its phenotype was analyzed. The mecB mutation eliminated mutacin I production, however, mutacin II and mutacin IV production is unaffected. In addition to mutacin production, the mecB mutation seemed also affect cell division. In Todd-Hewitt medium without sucrose, the mutant formed long cell chains, consisting well over 100 cells. These long cell chains coaggregate and precipitate to the bottom of the culture tube. These results suggest that the mecB gene in S. mutans also has a pleiotropic effect on cell growth. Other possible effect on the physiology of S. mutans is currently under investigation. Conclusion: The mecB gene in S. mutans is probably a pleiotropic regulator for mutacin production, cell division, and stress response. This study was supported by NIH grant R01 DE09082. | ||
| Seq #204 - Gram-positive Cocci: Molecular Biology II 11:00 AM-12:15 PM, Friday, 8 March 2002 San Diego Convention Center Exhibit Hall C | ||
|
Back to the Microbiology / Immunology and Infection Control Program
| ||