The Preparation and Screening of Several Novel Bacterial Homoserine Lactone Autoinducers

Abstract

The work described here explores the synthesis of known and potentially novel autoinducing molecules. Autoinducers, are small signaling molecules bacteria use to communicate to sense population density and control gene expression. Bacterial quorum sensing is the term used to describe this communication process. Two autoinducers have already been prepared in our lab: p‐coumaroyl homoserine lactone (p‐C‐HSL) and the novel N‐3‐oxooct‐7‐enoyl‐L‐homoserine lactone. The quorum sensing activities of both of these molecules have been tested in the Vibrio fisheri bacteria through established collaborations in the Fidopiastis lab here at Cal Poly. Luminescent/growth data suggests Vibrio fisheri responds to N‐3‐oxooct‐7‐enoyl‐L‐homoserine lactone but has diminished luminescence compared to the native autoinducer, N‐(3‐oxohexanoyl) homoserine lactone. Vibrio fischeri does not respond to p‐C‐HSL. However, p‐C‐HSL is a known autoinducer in the photosynthetic bacterium Rhodopseudomonas palustris. Reactivity profiling of both p‐C‐HSL and N‐3‐oxooct‐7‐enoyl‐L‐homoserine lactone is currently in progress to generate an extensive collection of reactivity data and novel derivatives. Lastly, the synthesis of another potential autoinducer, N‐3‐oxohept‐6‐enoyl‐L‐homoserine lactone is also being prepared in our lab; all of these molecules and derivatives will be tested for quorum sensing activity in the Vibrio fischeri bacteria.Long Range Research Goals: Because the quorum sensing mechanism of Vibrio fischeri is similar to that in other quorum sensing bacteria, these results can be used to demonstrate that synthetic autoinducers can trigger either a similar or possibly inhibited quorum sensing response. Further research would involve extrapolating this result to other quorum sensing bacteria behaviors, such as the production of toxins or antibiotic resistance. A potential goal would be to create an autoinducer that ultimately shuts down bacterial communication thereby inhibiting the formation of toxins in the first place.Support or Funding Information California Polytechnic State University, College Based Fee Fund