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Bonnie L. Bassler, Ph.D.
Until recently, the ability of bacteria to communicate with one another was considered an anomaly that occurred only among a few marine bacteria. It is now clear that “group talk” is the norm in the bacterial world, and understanding this process will be important in fighting deadly strains of bacteria, and in understanding communication between cells in the human body.
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Bonnie L. Bassler, Ph.D.
Professor of Molecular Biology
Princeton University
Princeton, New Jersey
Research Field: Microbiology, Genetics
Photo: Zack Seckler/AP, © HHMI
A high-resolution photograph is available on request.
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Bonnie Bassler has discovered that bacteria communicate with a chemical language. This process, called quorum sensing, allows bacteria to count their numbers, determine when they have reached a critical mass, and then change their behavior to carry out processes that require “mass action.”
For example, one process commonly controlled by quorum sensing is virulence. Virulent bacteria don’t want to start secreting toxins too soon, or the host’s immune system will be able to beat them back. Instead, Bassler explained, “they count themselves and when they reach the right number, they all launch an attack simultaneously. This way, the bacteria are more likely to overpower the immune system.” Quorum sensing, Bassler says, allows bacteria to act like enormous multicellular organisms. She has shown that this same basic mechanism of communication exists in some of the most virulent microbes, including those responsible for cholera and plague.
Working with a harmless marine bacterium that glows in the dark, Vibrio harveyi, Bassler and her colleagues discovered that this bacterium communicates with multiple chemical molecules. Some of these molecules, called autoinducers, allow V. harveyi to talk to its own kind, while one—called AI-2—allows the bacterium to talk to other bacterial species in its vicinity. Bassler showed that a gene called luxS is required for production of AI-2, and that hundreds of species of bacteria have this gene and use AI-2 to communicate. This work suggests that bacteria have a universal chemical language, a type of bacterial Esperanto that they use to talk between species.
Bassler’s research opens up the possibility of new strategies for combating important world health problems. Her team is currently working to find a way to disrupt the LuxS/AI-2 discourse so the bacteria either “can’t talk” or “can’t listen” to one another.
Her interest in bacterial communication grew from her curiosity about how information flows among cells in the human body, and she is convinced she will find parallels between the systems. “We have a chance to learn something fundamental in bacteria about chemical communication,” Bassler said. “If we can understand the rules or paradigms governing the process in bacteria, what we learn could hold true in higher organisms.”
Bassler won a 2002 MacArthur Fellowship, which she said provided tremendous validation for her group’s research, recognizing that “we are working on a problem that is much larger than a glow-in-the-dark bacterium.” She was also chosen as the 2004 Inventor of the Year by the New York Intellectual Property Law Association for her idea that interfering with the AI-2 language could form the basis of a new type of broad-spectrum antibiotic. “The fantasy is to make one pill that works against all kinds of bacteria,” she said.
Bonnie L. Bassler earned a B.S. in biochemistry at the University of California, Davis, and a Ph.D. in biochemistry at The Johns Hopkins University. She is Professor and Director of Graduate Studies in the Department of Molecular Biology at Princeton University.
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