My laboratory seeks to understand the signal transduction and its regulation underlying important microbial processes. This theme unifies our research in two major areas: environmental adaptation of Shewanella oneidensis, and secondary metabolites of marine microorganisms.

 

  • Shewanella oneidensis MR-1 is a facultatively anaerobic Gamma-Proteobacterium capable of utilizing a wide variety of compounds as electron acceptors, such as oxygen, iron, manganese, uranium, nitrate, nitrite, fumarate, thiosulfate, dimethyl sulfoxide, trimethylamine N-oxide, and elemental sulfur. Metabolic versatility, amenability to genetic manipulation, and availability of a full genome sequence make S. oneidensis MR-1 an excellent model system for studying microbial respiratory processes using high-throughput genomic-level experimental approaches. As a former member of the Shewanella Federation, I have conducted research collaboratively to understand the biology of S. oneidensis MR-1 at the whole-systems level for many years. At present, we focus on environmental adapation of this organism with an emphasis on its regulatory proteins.

 

  • Taxonomically diverse marine bacteria have proven to be a rich resource for the discovery of structurally unique and bioactive secondary metabolites. Given the intense microbial competition for resources such as space and nutrients, it is probable that many excreted metabolites help mediate microbe-microbe interactions. Prevention of coordinated bacterial behaviors such as swarming motility, antibiotic secretion, and biofilm production could greatly impede the success of a bacterial community in competing for space and other resources. Indeed, antagonists of quorum sensing and other cell-cell communication processes have been proposed as mechanistically novel antimicrobial drugs. Our current investigations are to survey the prevalence of such nontoxic interactions in the marine environment and also to better understand the ecological significance of such antagonism in bacterial competition.