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Current Research

RAM Physiology

Colorful, redox active metabolites (RAMs) are made by many different microbes. Their redox activity makes them fun to work with because they typically change color depending on their oxidation state. Historically overlooked as "secondary" metabolites, we have shown that phenazine RAMs play critical roles in helping Pseudomonas aeruginosa survive when it is growing slowly, particularly in the context of biofilms. Using diverse genetically-tractable bacteria that make a wide variety phenazines, we continue to explore the molecular mechanisms that underpin the physiological functions of RAMs.

Related Recent Publications:

Meirelles, Lucas A.*.;Perry, Elena M.* et al (2020) Bacterial defenses against a natural antibiotic promote collateral resilience to clinical antibiotics, bioRxiv

Saunders, Scott A..;Tse, Edmund T.S et al (2020) Extracellular DNA promotes efficient extracellular electron transfer by pyocyanin in Pseudomonas aeruginosa biofilms, Cell 182. doi: 10.1016/j.cell.2020.07.006

Ciemniecki, John A.;Newman, Dianne K. (2020) The potential for redox-active metabolites (RAMs) to enhance or unlock anaerobic survival metabolisms in aerobes Journal of Bacteriology; Vol. 202; No. 11

Chronic Infections

Chronic human infections cause major harm, including destroying the lungs of individuals living with cystic fibrosis and resulting in limb amputations due to wound healing failure in diabetics. Because the opportunistic pathogens causing these infections are growing slowly in hypoxic/anoxic environments, they are often physiologically tolerant to conventional antibiotics. We iterate between developing means to characterize the microenvironments in which these pathogens thrive in situ, and using reductionist in vitro approaches to understand how they do so to develop novel therapeutic approaches.

Related Recent Publications:

Basta, David W.;Angeles-Albores, David et al. (2020) Heat-shock proteases promote survival of Pseudomonas aeruginosa during growth arrest Proceedings of the National Academy of Sciences of the United States of America; Vol. 117; No. 8

Gallego-Hernandez, A. L.;DePas, W. H. et al. (2020) Upregulation of virulence genes promotes Vibrio cholerae biofilm hyperinfectivity Proceedings of the National Academy of Sciences of the United States of America; Vol. 117; No. 20

Jorth, Peter;Spero, Melanie A. et al. (2019) Quantitative visualization of gene expression in mucoid and nonmucoid Pseudomonas aeruginosa aggregates reveals localized peak expression of alginate in the hypoxic zone mBio; Vol. 10; No. 6

Rhizosphere Studies

In 1962, Rachel Carson wrote in Silent Spring: "There are few studies more fascinating, and at the same time more neglected, than those of the teeming populations that exist in the dark realms of the soil. We know too little of the threads that bind the soil microorganisms to each other and to their world, and to the world above." These words are more resonant today than ever, especially in the context of climate change and the critical role soil plays in carbon cycling and food security. Accordingly, we have begun to study phenazine-based microbial community interactions in diverse rhizospheres.

Related Recent Publications:

Dar, Daniel.;Thomashow, L.S. et al. (2020) Global landscape of phenazine biosynthesis and biodegradation reveals species-specific colonization patterns in agricultural soils and crop microbiomes eLife

Dahlstrom, Kurt M.;McRose, Darcy L.;Newman, Dianne K. (2020) Keystone metabolites of crop rhizosphere microbiomes Current Biology; Vol. 30, R1096–R1169

Perry, Elena K.;Newman, Dianne K. (2019) The transcription factors ActR and SoxR differentially affect the phenazine tolerance of Agrobacterium tumefaciens Molecular Microbiology; Vol. 112; No. 1