2024-2025: Biogeosciences: Dianne K. Newman

Dianne K. Newman

Caltech 

Biography

Dianne K. Newman is the Gordon M. Binder/Amgen Professor of Biology and Geobiology at Caltech. Dr. Newman’s 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.  Dr. Newman 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 MBL. 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. Dr. Newman 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.


Abstract: A Fascination with Phenazines and Maintenance Metabolism

My laboratory has long been fascinated by phenazines, a class of secreted redox-active metabolites produced by diverse soil bacteria, including the opportunistic human pathogen Pseudomonas aeruginosa.  One important context where phenazines are made is in biofilms: multicellular aggregates that are found in environments ranging from the surfaces of plant roots to within the tissues of chronic human infections.  Though phenazines were once thought to function primarily as antibiotics, we have found additional physiological functions for phenazines under anoxic conditions, including roles in signaling, energy conservation, and nutrient acquisition.  Recently, we have shown that phenazines support a non-growth state where bacteria remain active at an extremely low metabolic rate. Such a maintenance state characterizes how most bacteria exist in nature and disease yet has been difficult to study due to a lack of a quantitative and mechanistically-tractable experimental system. In this talk, I will discuss our emerging insights into how phenazines sustain one of the lowest metabolic rates ever reported for any organism, the extent to which these insights are generalizable, and how they may be leveraged to control biofilm populations.