Drexel University College of Medicine

Microbiology and Immunology Graduate Program B.S., Biology, Carnegie Mellon University Email: benjamin.janto@drexel.edu Advisor: Dr. Garth Ehrlich

Thesis Research Summary:

Coordinated population-based behavior in bacteria is accomplished through the production and sensing of small chemical compounds in a process that has been termed quorum sensing. Working in Dr. Ehrlich's lab at the Center for Genomic Sciences we have identified a cluster of genes in a subset of non-typeable Haemophilus influenzae (NTHi) that is known as the Lsr (LuxS-Regulated) operon. These genes encode an ABC transporter and intracellular modifying enzymes specific for the substrate autoinducer-2 (AI-2). AI-2 is produced as a byproduct of an enzymatic reaction mediated by LuxS, which is found in a wide range of gram negative and gram positive bacteria including NTHi. AI-2 and the Lsr operon have been implicated in the expression of virulence factors and have been linked to regulation of biofilm phenotype in various bacterial species. There is also evidence that organisms with the Lsr operon are able to influence the behavior of other communal species by sequestering AI-2. Alternatively, it has been hypothesized that the Lsr operon simply allows uptake and processing of AI-2 for metabolic benefit without any quorum sensing/gene regulation function. My research focuses on investigating the Lsr operon in NTHi to determine whether it confers a metabolic advantage, alters the virulence or biofilm phenotype, or has implications for cohabitation or competition with other bacterial species.