Bonnie Bassler, PhD

Squibb Professor and Chair
Department of Molecular Biology
Princeton University

Investigator, Howard Hughes Medical Institute

When Bonnie Bassler was an undergraduate student studying biochemistry, she was disappointed when she was assigned to a project studying bacterial enzymes. Bacteria were not important, the 19-year-old Bassler thought, and she wanted to study something weighty. During that project, however, she developed a lifelong appreciation for the biological complexity of bacteria. In fact, over the course of an extraordinary career since those days at the University of California, Davis, she has studied nothing but bacteria. Bassler’s many discoveries involving bacterial cell-cell communication have revolutionized the study of microbiology, transformed the way we think about bacteria, and yielded profound insight into how a more complete understanding of bacteria could pave the way to biological solutions to global problems of health, nutrition, and the environment.

In 1990, as Bassler neared completion of her PhD studies in biochemistry at the Johns Hopkins University, she attended a conference where she heard a fascinating seminar about what is now called quorum sensing, the process by which bacterial cells communicate chemically. The presenter showed that bioluminescent marine bacteria produce light only when they exist in large numbers. He showed the molecule that this particular species uses to communicate to one another that they are in a group, and he eloquently made the case that these bacteria were behaving like a multicellular organism. Intrigued, Bassler immediately asked for and was eventually granted a job in his lab, becoming a postdoctoral fellow under Michael Silverman, PhD, of the Agouron Institute in La Jolla, Calif. There, Bassler further delved into the study of bacterial cell-cell communication, which led to her discovery of new quorum-sensing systems and the possibility of additional quorum-sensing molecules in related bacteria.

In 1994, Bassler moved to Princeton University and accelerated her investigations in the growing field of quorum sensing. She discovered and characterized new molecules involved in bacterial cell-cell communication, suggesting that bacteria harbor a multitude of chemicals with novel functions and potential uses in medicine. She also made the surprising discovery that bacteria communicate across species boundaries and that they use specific chemical “words” to detect self, related bacteria, and others. This revolutionary finding that the simplest organisms on the planet shared a common chemical “language” led to Bassler’s being named a fellow of the MacArthur Foundation in 2002.

Bassler, now the Squibb Professor and chair of the Department of Molecular Biology at Princeton and an investigator of the Howard Hughes Medical Institute, has continued to reveal the complexity of bacterial languages throughout her career. She has shown how bacteria tailor their activities, depending on whether they are surrounded by friend or foe. She also demonstrated that bacterial cell-cell communication is essential for virulence in some bacterial pathogens of global significance, including Vibrio cholerae, which can cause deadly cholera epidemics. Using quorum sensing, bacteria refrain from producing toxins when they exist in small numbers and can easily be destroyed by their host’s immune system. Only when they exist in sufficient numbers do they employ quorum sensing to launch a coordinated attack against the host. Inspired by her discovery that bacteria actively interfere with chemical communication by other bacteria, Bassler has developed synthetic strategies for manipulating quorum sensing to halt virulence in pathogens. Because these strategies target bacterial behavior, not growth, such therapies are potentially much less vulnerable to the development of resistance compared to traditional antibiotics. In addition, Bassler and her colleagues have shown that quorum sensing can be manipulated to prevent bacteria from adhering to medical devices and to stop them from forming antibiotic-resistant communities called biofilms in medical settings.

Throughout her career, Bassler has been a passionate advocate for diversity in the sciences, and she is actively involved in and committed to public science education. In addition to being named a fellow of the MacArthur Foundation, Bassler has received many honors, including election to the National Academy of Sciences, the National Academy of Medicine, the American Academy of Arts and Sciences, the Royal Society, and the American Philosophical Society. Bassler’s awards include the 2012 L’Oreal-UNESCO For Women in Science award, the 2015 Shaw Prize in Life Science and Medicine, and the 2016 Pearl Meister Greengard Prize. She was the 2006 recipient of the American Society for Microbiology’s Eli Lilly Investigator Award for fundamental contributions to microbiological research, the 2009 recipient of the Wiley Prize in Biomedical Sciences for paradigm-changing scientific research, and the 2011 recipient of the Richard Lounsbery Award of the National Academies. In 2008, Bassler received the Princeton University President’s Award for Distinguished Teaching. For six years, she was a member of the National Science Board, which oversees the National Science Foundation and prioritizes the nation’s research and educational activities in science, math, and engineering. She was nominated to that position by President Barack Obama.