Electrically induced bacterial membrane-potential dynamics correspond to cellular proliferation capacity

Stratford, James P.; Edwards, Conor La; Ghanshyam, Manjari J; Malyshev, Dmitry; Delise, Marco A; Hayashi, Yoshikatsu; Asally, Munehiro

doi:10.1073/pnas.1901788116

Cited by 136 publications

(98 citation statements)

References 60 publications

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“…Fluorescent sensors of voltage and calcium have been used to monitor electrophysiology in bacteria at the single cell level with high time resolution 22,23,26,29 . We used the genetically encoded sensor, PROPS, to measure voltage dynamics after 2 hours of treatment with kanamycin.…”

Section: Voltage and Calcium Exhibit Altered Electrophysiological Flumentioning

confidence: 99%

“…Improvements in microscope hardware enable automated live cell imaging while resolving the responses of individual bacteria. This hardware can be coupled with genetically encoded, or chemical fluorescent sensors that report bacterial voltage [20][21][22] , calcium 23 , and ATP 24,25 , providing a lens to explore the long-term effects of antibiotic exposure. Recently, live cell voltage imaging of Bacillus subtilis revealed the importance of membrane potential in response to translation inhibitors 26 .…”

Section: Introductionmentioning

confidence: 99%

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Membrane voltage dysregulation driven by metabolic dysfunction underlies bactericidal activity of aminoglycosides

Bruni

Kralj

2020

Preprint

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Aminoglycosides are broad-spectrum antibiotics whose mechanism of bactericidal activity has been under debate. It is widely accepted, however, that membrane voltage potentiates aminoglycoside activity, which is ascribed to voltage dependent drug uptake. In this paper, we measured the single cell response of Escherichia coli treated with aminoglycosides and discovered that the bactericidal action arises not from the downstream effects of voltage dependent drug uptake, but rather directly from dysregulated membrane potential. In the absence of voltage, aminoglycosides are taken into cells and exert bacteriostatic effects by inhibiting translation. However, cell killing was immediate upon re-polarization. The hyperpolarization arose from altered ATP flux, which induced a reversal of the F1Fo-ATPase to hydrolyze ATP and generated the deleterious voltage. Heterologous expression of an ATPase inhibitor from Salmonella completely eliminated bactericidal activity, while loss of the F-ATPase significantly reduced the electrophysiological response to aminoglycosides. Our data support a model of voltage induced death, which could be resolved in real-time at the single cell level, and separates the mechanisms of aminoglycoside bacteriostasis and bactericide in E. coli.

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Section: Voltage and Calcium Exhibit Altered Electrophysiological Flumentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Membrane voltage dysregulation driven by metabolic dysfunction underlies bactericidal activity of aminoglycosides

Bruni

Kralj

2020

Preprint

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“…This opens up the possibility of 'dialling in' on cellular behaviour at the singlecell and tissue levels. It has been shown for example that electric fields can influence or stop mammalian cell division [61,63] or trigger specific cellular responses [60,64] and can be used to distinguish between metabolically active and dormant bacterial cells [35]. Techniques such as SECM can directly deliver redox-active compounds to individual cells and measure their responses; for example, to interrogate the metabolism of cancerous versus normal cells [65].…”

Section: Bioelectrical Engineering Of Cell Biology: Potential and Chamentioning

confidence: 99%

Bioelectrical understanding and engineering of cell biology

Schofield

Meloni

Tran

et al. 2020

J. R. Soc. Interface.

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The last five decades of molecular and systems biology research have provided unprecedented insights into the molecular and genetic basis of many cellular processes. Despite these insights, however, it is arguable that there is still only limited predictive understanding of cell behaviours. In particular, the basis of heterogeneity in single-cell behaviour and the initiation of many different metabolic, transcriptional or mechanical responses to environmental stimuli remain largely unexplained. To go beyond the status quo , the understanding of cell behaviours emerging from molecular genetics must be complemented with physical and physiological ones, focusing on the intracellular and extracellular conditions within and around cells. Here, we argue that such a combination of genetics, physics and physiology can be grounded on a bioelectrical conceptualization of cells. We motivate the reasoning behind such a proposal and describe examples where a bioelectrical view has been shown to, or can, provide predictive biological understanding. In addition, we discuss how this view opens up novel ways to control cell behaviours by electrical and electrochemical means, setting the stage for the emergence of bioelectrical engineering.

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“…Indeed, LytC is activated upon sodium azide treatment that deprotonates the cell wall [53, 54] and the activity of peptidoglycan synthesis enzymes in E. coli are regulated by pH [55, 56]. In addition, the recent observation that actively growing and dormant cells in a B. subtilis culture respond oppositely to an electrical pulse wherein they either hyperpolarize or depolarize, respectively [57], suggests that membrane energetics may explain the observed population heterogeneity in our oxygen-depleted 3610 cultures. Thus, as membrane potential is of utmost importance in metabolism and cell growth, is becoming more appreciated in regulating cell-wall remodeling, and likely feeds back into many additional aspects of cell physiology, bacteria must employ strategies to maintain and/or modulate membrane potential during changing environmental conditions.…”

Section: Discussionmentioning

confidence: 99%

Biosurfactant production maintains viability in anoxic conditions by depolarizing the membrane inBacillus subtilis

Arjes

Dunn

et al. 2019

Preprint

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20membrane potential, membrane energetics, LytC 21 35 depolarizes the B. subtilis membrane, and that other known membrane-potential 36 disruptors restore viability to 168. These findings highlight the importance of surfactin for 37 survival during oxygen-depleted conditions and demonstrate that antimicrobials normally 38 considered harmful can instead benefit cells in stressful conditions when the terminal 39 electron acceptor in respiration is limiting. 40 following a rain [12]. Early observations of B. subtilis culture lysis upon a shift to anoxic 64 environments have yet to be further characterized [13], and it remains a mystery whether 65 B. subtilis has strategies to cope with oxygen limitation. 66 B. subtilis has long been domesticated in the lab, leading to a multitude of genetic 67 tools, strain libraries, and online databases and resources [14][15][16]. The high level of genetic 68 relatedness between biofilm-forming "wild" strains and derivative non-biofilm-forming 69 laboratory strains has been exploited to identify genetic differences that underlie biofilm 70 community behaviors [17]. For instance, the commonly studied laboratory strain 168, 71 which is derived from the biofilm-forming strain 3610, lacks an extrachromosomal plasmid 72 and harbors several point mutations that reduce or abolish social behaviors such as matrix 73 production [18]. Notably, 3610 produces the small molecule surfactin, a powerful 74 surfactant that has previously been implicated in swarming motility [19][20][21]. Surfactin has 75 also been shown to kill fungi [22] and some bacteria in vitro [22][23][24][25][26]. However, fitness 76 benefits of surfactin production in the context of planktonic cultures have yet to be 77 identified, although some surfactants can accelerate oxygen diffusion through the air-water 78 interface [27]. 79 Here, we characterize the interplay between oxygen availability and surfactin 80 production during the growth and death of B. subtilis cultures. We show that oxygen 81 becomes limiting in the culture during the transition to stationary phase and that surfactin 82 secretion improves growth yield in stationary phase by increasing oxygen availability. 83 During a shift to anoxic conditions, we demonstrate that the majority of B. subtilis cells die 84 and lyse due to the activity of the LytC autolysin and surfactin. Finally, we discover that 85 surfactin maintains the viability of the remaining cells by causing membrane 86 depolarization that allows these cells to survive until oxygen is restored. 87 131 hour (Fig. 1D). Since the lysis behavior varied with initial OD, we standardized all further 132 experiments by growing 3610 cells to an OD600 of ~0.9-1.1 before cutting off oxygen 133

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Electrically induced bacterial membrane-potential dynamics correspond to cellular proliferation capacity

Cited by 136 publications

References 60 publications

Membrane voltage dysregulation driven by metabolic dysfunction underlies bactericidal activity of aminoglycosides

Membrane voltage dysregulation driven by metabolic dysfunction underlies bactericidal activity of aminoglycosides

Bioelectrical understanding and engineering of cell biology

Biosurfactant production maintains viability in anoxic conditions by depolarizing the membrane inBacillus subtilis

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