Unveiling Low-Power Survival Strategies on Life’s Metabolic Edge
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Dianne Newman, Ph.D.
Gordon M. Binder/Amgen Professor of Biology and Geobiology
Merkin Institute Professor
California Institute of Technology
Dianne Newman is a molecular microbiologist, a professor in the Division of Biology and Biological Engineering and the Division of Geological and Planetary Sciences at California Institute of Technology. Her research interests include bioenergetics and cell biology of metabolically diverse, genetically-tractable bacteria. Her work deals with electron-transfer reactions that are part of the metabolism of microorganisms. She was awarded the National Academy of Sciences (NAS) Award in Molecular Biology for her "discovery of microbial mechanisms underlying geologic processes." The award citation recognizes her for "launching the field of molecular geomicrobiology" and fostering greater awareness of the important roles microorganisms have played and continue to play in how Earth evolved. In 2025, she was elected to the American Philosophical Society. She was one of the recipients of the 2016 MacArthur Fellowships. She was elected to the National Academy of Sciences in 2019.
Summary
Mechanistic studies of life’s lower metabolic limits have been limited due to a paucity of tractable experimental systems. In this presentation, I will describe how we can investigate the physiology of maintenance (metabolic activity in the absence of growth) by studying anaerobic phenazine cycling in bacteria. Phenazines are a class of redox-active metabolites produced by diverse organisms. Using Pseudomonas aeruginosa as a model phenazine-producer, we have shown that anaerobic phenazine cycling supports cellular maintenance for non-growing cells in the cores of biofilms. This maintenance metabolism has a very low mass-specific metabolic rate (among the lowest ever measured for any organism). In this state, non-growing cells tolerate conventional antibiotics, motivating the identification of cellular machinery that underpin maintenance physiology as a first step towards identifying better drug targets. I will show how a quantitative, high-throughput electrochemical platform can be leveraged to identify this machinery, providing a specific example of how energy is conserved under these conditions. This platform opens the door to further mechanistic investigations of maintenance, a physiological state that underpins microbial survival in nature and disease.
Learning Objectives:
- To understand that most microbes in nature and disease exist in biofilms.
- To appreciate that cells within the core of biofilms are metabolically active but not growing, resulting in their tolerance to conventional antibiotics.
- To learn how electrochemical methods can help interrogate how cells within the biofilm core survive, paving the way to the identification of better drug targets.
This page was last updated on Monday, April 13, 2026