Online
Date: Thursday, December 19
Time: 5:30 – 7:00 pm
If you would like to attend, register in advance for this webinar.
After the webinar, you are invited to talk to the speaker and mingle with other alumni in a post-webinar social via a Zoom meeting.
We look forward to seeing you.
Peter Tong
How Phenazines Keep Bacteria Alive in Biofilms
By Dianne Newman
Biofilms are found in all sorts of areas, ranging from the surface of plant roots, slimy rocks in streams, dental plaque, to within the tissues of chronic human infections. They are multicellular aggregates encased in a self-produced polymeric matrix.
Biofilms cause persistent infections in humans because they tolerate conventional antibiotics. Our inability to control biofilms springs from our lack of understanding of how cells in biofilms survive when they are not growing.
Phenazines are key to the survival of certain biofilm-forming bacteria. They are a class of secreted redox-active metabolites produced by diverse organisms, including Pseudomonas aeruginosa (a leading hospital-acquired pathogen that causes a wide range of acute and chronic infections).
Phenazines were once thought to function primarily as antibiotics. But we have found core physiological functions for phenazines even in the absence of oxygen, including roles in signaling, energy conservation, and nutrient acquisition.
Recently, we also have shown that phenazines enable bacteria to remain metabolically active while not growing. In other words, even in microenvironments with severely-limited resources, phenazines can keep bacteria alive!
As there is often no oxygen deep within infectious biofilms, phenazines are crucial to bacteria survival in these regions—and thus, a potentially potent target for therapeutic drugs.
Such a maintenance state characterizes how most bacteria exist in nature and diseases. But studying such a state has been difficult due to a lack of a quantitative and mechanistically-tractable experimental system.
In this talk, I will discuss our development of such a system, and our emerging insights into how phenazines sustain one of the lowest metabolic rates ever reported for any organism, the extent to which these insights may be generalized, and how they may be leveraged to control biofilm populations.
Caltech recently published an article on this subject.
Dianne K. Newman is the Gordon M. Binder/Amgen Professor of Biology and Geobiology at Caltech. Her interdisciplinary research focuses on elucidating mechanisms of energy conservation and survival when oxygen is scarce, with an emphasis on how redox-active extracellular electron shuttles sustain metabolically attenuated biofilms. The contexts that motivate her research span chronic human infections to the rhizosphere, yet are linked by a basic curiosity about how a low power lifestyle is achieved.
Dianne earned her PhD in Environmental Engineering at MIT with Francois Morel and trained as a postdoc in Microbiology and Molecular Genetics at Harvard Medical School with Roberto Kolter. She joined the Caltech faculty in 2000 as the Clare Boothe Luce Assistant Professor of Geobiology and Environmental Science. From 2007-2010 she was the Wilson Professor of Biology and Geobiology at MIT, and from 2005-2016, a Howard Hughes Medical Institute Investigator. From 2014-2017 she co-directed the Microbial Diversity Course at the Marine Biological Laboratory.
Her honors include the National Academy of Science’s Award in Molecular Biology and a MacArthur Fellowship, but she is most proud of her trainees, who have gone on to lead successful scientific careers in academia, industry, government, and the non-profit sector.
Dianne is a Member of the National Academy of Sciences and the American Academy of Arts and Sciences, and a Fellow of the American Academy of Microbiology and the American Geophysical Union.
Currently, she is leading the Ecology and Biosphere Engineering Initiative for Caltech’s Resnick Sustainability Institute and serves on the Scientific Advisory Committee of the European Molecular Biology Laboratory.
Our Alumni Volunteers
The following alumni work together to serve you:
Avni Gandhi, Dave Adler, Jane Frommer, Mike Klein, Xinh Huynh, and Peter Tong.