Ann Stevens, associate professor of biology at Virginia Tech, studies how cell-to-cell interaction regulates bacterial processes that include antibiotic or toxin production, biofilm formation, and bioluminescence. One of the longest studied models of quorum sensing is the bioluminescent marine bacterium V. fischeri.
"It was selected by Drs. Ruby and Greenberg to be sequenced exactly because it is so well studied," said Stevens. "This was also the first time a non-pathogenic Vibrio species has been sequenced and there is the potential for valuable lessons as it is compared with the pathogenic species. I was particularly pleased when my graduate student, Marie Faini, and I were given the opportunity to be members of the team that annotated the sequence."
Annotation is a complex process that assigns functions to genes. Having access to the genetic sequence in order to perform this chore gave Stevens and Faini early access to specific information about the genes of the bacterium she has been studying for several years.
Many different bacteria use quorum sensing. Stevens explains that cells release autoinducer molecules. The numbers of these signal molecules increase with cell density, until they initiate various reactions, such as light production ?or, in a pathogen, the release of toxin once a certain level of bacteria build up.
Stevens studies the regulation system of the cell-to-cell communication. "Our quorum sensing research group at Virginia Tech is working to build a more complete understanding of the molecular processes that occur at the point that a bacterium changes its gene expression pattern in response to quorum sensing," she said. The genome sequence has allowed Stevens to begin exploring the connection between quorum sensing and other global regulatory networks through a combination of comparative genomics and experimental molecular biology.
Other researchers are focusing on the relationshi