The $1.8 million National Science Foundation-funded project will look specifically at signal molecules that initiate a bacterial chemical communication process called quorum sensing. The intricate chemistry of quorum sensing relates to the spread of disease, the resistance of infections in medicine, and the recently discovered high diversity of bacteria within certain natural environments.

“Imagine a city with half a million people—if they don’t communicate, chaos would result,” said Alan Decho, a professor in the Department of Environmental Health Sciences in the Arnold School of Public Health and the principal investigator of the project. “In the same way, individual bacterium in a bacterial colony becomes much more resilient by working together.”

Decho is collaborating with three scientists from the Department of Chemistry and Biochemistry—John Ferry, Michael Angel, and Lee Ferguson—to examine how signal molecules are transformed under environmental conditions and how the molecules interact with protein receptors within cells. Their research on the chemistry of the signal molecules could help clinicians develop better ways to combat infections by confusing or blocking the signal process.

Bacteria don’t always use quorum sensing for pathogenic purposes. Common bacteria living on the surface of the intestines likely communicate with intestinal tissue using quorum sensing, and are thought to aid the intestines in protecting against pathogenic bacteria. This battle between ‘good’ and ‘bad’ bacteria is often fought by communication signals.

“If one group of bacteria can communicate and coordinate gene expression [using quorum sensing] successfully, they can act as a more efficient and resilient unit, rather than just a bunch of individuals,” Decho said. “Conversely, if a bacterial group can produce molecules that interfere with the communication signals of another group, they render them useless and overtake them. So, understanding quorum sensing has implications for development of a new generation of antimicrobial agents and antibiotics.”

The project idea arose from an ongoing NSF-funded study examining bacteria in the natural environment, from microbial mats in an isolated area of the Bahamas. Some microbial mats have the highest diversity of life on earth—more species in a thimble of sediment, than a rainforest ecosystem. While much is known about the biology and molecular biology of quorum sensing, a real ‘black box’ exists in understanding the chemistry of this process.

Several types of state-of-the-art instrumentation such as a surface-plasmon resonance spectrometer and pulsing-Raman laser, will be purchased through the grant. New techniques, including high-throughput multivariate environmental transformation studies and new spectroscopic tools to detect low levels of autoinducer molecules in complex environmental samples will be developed.

The project also will provide opportunities for undergraduates and graduate students to acquire knowledge and skills in broad areas of environmental analytical chemistry, spectroscopy, and microbiology.

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