January 3, 2006
Dental researchers have long viewed the tooth-decay-causing bacterium Streptococcus mutans as one of the most biologically interesting organisms in the mouth. In the November 29, 2005 issue of the journal Proceedings of the National Academy of Sciences, a group of NIDCR grantees reported this oral bacterium might be more biologically revealing than anyone could have imagined. The scientists found quite unexpectedly that S. mutans can survive without a functioning signal recognition particle (SRP)-translation pathway. This biochemical pathway plays a key role in folding and chaperoning needed proteins to our cell membranes, a task that scientists have long viewed as essential to life. With the previously reported exception of brewer’s yeast and now S. mutans, no other organism has shown it can survive without this pathway intact to maintain the viability of the cell membrane. According to the scientists, S. mutans seems to activate a backup pathway that allows it continue to grow and function.