Research
One focus of the lab is how V. fischeri cells communicate using pheromone signals. Such bacterial signaling is often termed "quorum sensing" and is typically depicted as regulation in response to high cell density or "quorum". However, it is now clear that the pheromones are not simply census-taking molecules and can perform more complicated social roles. The pheromones in V. fischericontrol the lux genes responsible for bioluminescence, and the pheromones are controlled by themselves in positive-feedback loops and by environmentally responsive regulators, including ArcA/ArcB, Crp, Fur, and others. This raises the intriguing possibility that in addition to reflecting cell density, bacterial pheromones may coordinate behaviors, such as the group decision to bioluminesce, in response to local environmental cues. Interestingly, bioluminescence is induced upon entering the symbiosis, and dark (lux) mutants are attenuated in colonizing the E. scolopeslight organ; however, the symbiotic role of bioluminescence remains unclear. Studying pheromone-mediated regulation may help shed light on the purpose of bioluminescence. We have embarked on a collaborative project to model and understand how V. fischeriuses multiple pheromones to underpin its cell-cell communication.
A second major focus of the lab is aimed at understanding the interspecies signaling by which the squid host recognizes and responds to V. fischeri. Peptidoglycan and LPS can trigger changes in host development that parallel those seen during normal symbiotic infection. We are interested in how and why V. fischerireleases peptidoglycan monomer, which acts as a morphogen on the host.
Currently, a project in the lab is using V. fischerias a model to understand how new peptidoglycan structures can evolve in bacteria.
Many projects in the lab are underpinned by genetic approaches, and we are often developing genetic and genomic tools for V. fischeri. For example, characterizing the small V. fischeri plasmid pES213 led to an array of shuttle vectors that is still expanding. We have also pioneered improved methods for mutagenesis with mini-Tn5 in V. fischeri.
A second major focus of the lab is aimed at understanding the interspecies signaling by which the squid host recognizes and responds to V. fischeri. Peptidoglycan and LPS can trigger changes in host development that parallel those seen during normal symbiotic infection. We are interested in how and why V. fischerireleases peptidoglycan monomer, which acts as a morphogen on the host.
Currently, a project in the lab is using V. fischerias a model to understand how new peptidoglycan structures can evolve in bacteria.
Many projects in the lab are underpinned by genetic approaches, and we are often developing genetic and genomic tools for V. fischeri. For example, characterizing the small V. fischeri plasmid pES213 led to an array of shuttle vectors that is still expanding. We have also pioneered improved methods for mutagenesis with mini-Tn5 in V. fischeri.