Prather Lecture Series

Dr. Bonnie L. Bassler, Squibb Professor in Molecular Biology, Chair Department of Molecular Biology, to give 2017 Prather Lectures,

March 1, 2, & 3, 2017

Bonnie L. Bassler

Dr. Bonnie Bassler is a member of the National Academy of Sciences and the American Academy of Arts and Sciences. She is a Howard Hughes Medical Institute Investigator and the Squibb Professor and Chair of the Department of Molecular Biology at Princeton University. Dr. Bassler received a B.S. in Biochemistry from the University of California at Davis, and a Ph.D. in Biochemistry from the Johns Hopkins University. She performed postdoctoral work in Genetics at the Agouron Institute, and joined the Princeton faculty in 1994. The research in Dr. Bassler's laboratory focuses on the molecular mechanisms that bacteria use for intercellular communication. This process is called quorum sensing. Dr. Bassler’s research is paving the way to the development of novel therapies for combating bacteria by disrupting quorum-sensing-mediated communication. At Princeton, Dr. Bassler teaches both undergraduate and graduate courses. She directed the Molecular Biology Graduate Program from 2002-2008 and in that role launched a highly successful and sustainable program to increase recruiting and matriculation of students from under-represented groups. Dr. Bassler chaired Princeton University’s Council on Science and Technology for 6 years and during that time she rejuvenated the science curriculum for humanists. Dr. Bassler is a passionate advocate for diversity in the sciences and she is actively involved in and committed to educating lay people in science. Dr. Bassler was awarded a MacArthur Foundation Fellowship in 2002. She was elected to the American Academy of Microbiology in 2002, and made a fellow of the American Association for the Advancement of Science in 2004. She is the 2006 recipient of the American Society for Microbiology’s Eli Lilly Investigator Award for fundamental contributions to microbiological research. In 2008, Dr. Bassler received Princeton University’s President’s Award for Distinguished Teaching. She is the 2009 recipient of the Wiley Prize in Biomedical Science for her paradigm-changing scientific research. She is the 2011 recipient of the National Academies’ Richard Lounsbery Award and she is the 2012 UNESCO-L’Oreal Woman in Science for North America. In 2012, Dr. Bassler was elected to the Royal Society and to the American Philosophical Society. She received the Shaw Prize in Life Sciences and Medicine in 2015. In 2016, she received the Pearl-Meister Greengard Prize and the Max Planck-von Humboldt Research Prize. Also in 2016, Dr. Bassler was elected to the National Academy of Medicine. Dr. Bassler was the President of the American Society for Microbiology in 2010-2011, and she chaired the American Academy of Microbiology Board of Governors from 2011-2014. She was a member of the National Science Board for six years and was nominated to that position by President Barack Obama. The Board oversees the NSF and prioritizes the nation’s research and educational activities in science, math, and engineering.

Wednesday, March 1
4:00pm
Geological Lecture Hall, 24 Oxford Street
Free and open to the public

Bacterial Quorum Sensing and Its Control

Quorum sensing is a bacterial cell-cell communication process that relies on the production, detection, and group-wide response to extracellular signal molecules called autoinducers. Quorum sensing enables bacteria to synchronously alter behavior in response to changes in population density and species composition of the vicinal community. Often, quorum sensing controls virulence factor production and biofilm formation. We aim to make pro- and anti-quorum-sensing modulators to use as probes to further our basic research and to demonstrate their potential as novel therapeutics. In this realm, we discovered synthetic compounds that interfere with quorum sensing by acting on the transmembrane autoinducer receptors as well as on intracellular quorum-sensing signal transduction components. Structural analyses revealed both the natural and synthetic mechanisms by which these proteins are regulated. With respect to the role of quorum sensing in biofilm formation, we developed imaging technology capable of resolving and tracking individual cells in living, growing biofilms. We characterized the biofilm formation process of wild type and mutant strains in the presence of flow and under topographical conditions mimicking environmental, medical, and industrial systems. These studies connect the microscale structure of biofilms and their corresponding gene expression patterns with the macroscopic physical properties of biofilms, e.g. viscoelasticity, structural strength, resistance to invading cells, and impermeability to antibiotics.

Thursday, March 2
6:00pm
Geological Lecture Hall, 24 Oxford Street
Free and open to the public

Tiny Conspiracies: Cell-to-Cell Communication in Bacteria

Bacteria are tiny ancient organisms. Harmful bacteria have the capacity to kill humans, animals, and plants, while beneficial bacteria play vital roles in keeping humans, animals, and plants alive. How do bacteria do it? They are so small yet they carry out such big jobs. The answer is that bacteria work in groups: They communicate, count their numbers, and act as collectives. Bacteria communicate with one another using chemical molecules that they release into the environment. These molecules travel from cell to cell and the bacteria have receptors on their surfaces that allow them to detect and respond to the build up of the molecules. This process of cell-to-cell communication in bacteria is called “Quorum Sensing” and it allows bacteria to synchronize behavior on a population-wide scale. Bacterial behaviors controlled by quorum sensing are ones that are unproductive when undertaken by an individual bacterium acting alone but become effective when undertaken in unison by the group. For example, quorum sensing controls virulence, biofilm formation, and the exchange of DNA. Current biomedical research is focused on development of therapies to interfere with quorum sensing. Such therapies could be used to combat bacterial pathogenicity.

 

Friday, March 3
10:00am
Geological Lecture Hall, 24 Oxford Street
Free and open to the public

How Bacteria Tell Self from Other

Bacteria communicate with one another via the production and detection of secreted signal molecules called autoinducers. This cell-to-cell communication process, called quorum sensing, allows bacteria to synchronize behavior on a population-wide scale. Behaviors controlled by quorum sensing are usually ones that are unproductive when undertaken by an individual bacterium acting alone but become effective when undertaken in unison by the group. For example, quorum sensing controls virulence factor production, biofilm formation, and the excretion of public goods such as enzymes that solubilize solid food sources making them accessible for consumption. We developed small molecule quorum-sensing agonists and antagonists to discover the principles underlying the exquisite selectivity quorum-sensing receptors have for their cognate ligands. Our results suggest mechanisms bacteria use in the wild to ensure the proper ligand has interacted with its partner receptor prior to eliciting signal transduction. We suggest that, in their native environments, bacteria encounter mixtures of autoinducers produced by other bacterial species occupying the same niche. Precise autoinducer discrimination enables a particular species of bacteria to respond exclusively to its own signal even in the face of fierce competition. This ability prevents the leakage of benefits of quorum-sensing-controlled public goods to non-kin. Beyond learning about fundamental principles underlying quorum sensing, another use for our synthetic molecules is to control quorum sensing on demand.