Mechanistic study of a low-power bacterial maintenance state using high-throughput electrochemistry
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1.
California Institute of Technology
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2.
National Institute for Materials Science
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3.
Hokkaido University
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4.
University of Tsukuba
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5.
Tokyo Institute of Technology
Abstract
Mechanistic studies of life's lower metabolic limits have been limited due to a paucity of tractable experimental systems. Here, we show that redox-cycling of phenazine-1-carboxamide (PCN) by Pseudomonas aeruginosa supports cellular maintenance in the absence of growth with a low mass-specific metabolic rate of 8.7 × 10-4 W (g C)-1 at 25°C. Leveraging a high-throughput electrochemical culturing device, we find that non-growing cells cycling PCN tolerate conventional antibiotics but are susceptible to those that target membrane components. Under these conditions, cells conserve energy via a noncanonical, facilitated fermentation that is dependent on acetate kinase and NADH dehydrogenases. Across PCN concentrations that limit cell survival, the cell-specific metabolic rate is constant, indicating the cells are operating near their bioenergetic limit. This quantitative platform opens the door to further mechanistic investigations of maintenance, a physiological state that underpins microbial survival in nature and disease.
Copyright and License
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Acknowledgement
This work was supported by NIH grant (2R01AI127850-06A1) to D.K.N. This work was supported by JSPS KAKENHI (22H02265 and 22KK0242) and JST GteX (JPMJGX23B4) to A.O. We are grateful to Georgia Squyres and Sean Wilson for their help with the HADA experiment and Avi Flamholz and other members of the Newman lab for constructive feedback throughout the study.
Contributions
Conceptualization, J.A.C., A.O., and D.K.N.; methodology, J.A.C., C.-L.H., R.D.H., A.O., and D.K.N.; investigation and validation, J.A.C., C.-L.H., and R.D.H.; formal analysis and visualization, J.A.C.; resources, A.O. and D.K.N.; writing – original draft, J.A.C. and D.K.N.; writing – review & editing, J.A.C., C.-L.H., R.D.H., A.O., and D.K.N.; supervision and funding acquisition, A.O. and D.K.N.
Supplemental Material
- Document S1. Supplemental references.
- Methods S1. Analysis of bacterial metabolic rate data from Hoehler et al., related to Figure 2.
- Table S1. Hoehler et al. bacterial metabolic rates dataset with units transformed to electrons s−1 cell−1, related to Figure 2.
Files
Additional details
- National Institutes of Health
- 2R01AI127850-06A1
- Japan Society for the Promotion of Science
- KAKENHI 22H02265
- Japan Society for the Promotion of Science
- KAKENHI 2KK0242
- Japan Science and Technology Agency
- GteX JPMJGX23B4
- Accepted
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2024-09-26Accepted
- Available
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2024-10-23Published online
- Available
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2024-11-27Version of record
- Caltech groups
- Division of Biology and Biological Engineering
- Publication Status
- Published