Evidence map›Paper›PMID 39798601›Full record

ArticleBiophysical reports2025

Toward measurements of absolute membrane potential in Bacillus subtilis using fluorescence lifetime.

Debjit Roy, Xavier Michalet, Evan W Miller, Kiran Bharadwaj, Shimon Weiss

Abstract read
PubMed Full text at PMC Publisher
In one paragraph

Article in Biophysical reports, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers.

0numbers the graph read from it
0cells of the map it votes in
4citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

4 citing papers in PubMed.

  1. Review
  2. Article
  3. AlliGator: Open Source Fluorescence Lifetime Imaging Analysis in G.bioRxiv : the preprint server for biology · 2025
    Article
  4. Bioelectricity, Moving On….Bioelectricity · 2025
    Article
4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

5 authors.

Debjit RoyUCLA-DOE Institute for Genomics and Proteomics, Department of Biological Chemistry, University of California at Los Angeles, Los Angeles, California; Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, California.
Xavier MichaletDepartment of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, California; California Nano Systems Institute, University of California at Los Angeles, Los Angeles, California. Electronic address: michalet@chem.ucla.edu.
Evan W MillerDepartments of Chemistry, Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California at Berkeley, Berkeley, California.
Kiran BharadwajUCLA-DOE Institute for Genomics and Proteomics, Department of Biological Chemistry, University of California at Los Angeles, Los Angeles, California; Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, California.
Shimon WeissUCLA-DOE Institute for Genomics and Proteomics, Department of Biological Chemistry, University of California at Los Angeles, Los Angeles, California; Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, California; Department of Physiology, University of California at Los Angeles, Los Angeles, California; California Nano Systems Institute, University of California at Los Angeles, Los Angeles, California; Department of Physics, Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel. Electronic address: sweiss@chem.ucla.edu.

Funding

Chemical Approaches to Visualize and Quantify Cellular PhysiologyR35GM153237 · NIGMS · UNIVERSITY OF CALIFORNIA BERKELEY · PI Evan Walker Miller · 2024 to 2026
$1.3M
NIGMS NIH HHS R35 GM153237
6 · The paper itself

Abstract

Membrane potential (MP) changes can provide a simple readout of bacterial functional and metabolic state or stress levels. While several optical methods exist for measuring fast changes in MP in excitable cells, there is a dearth of such methods for absolute and precise measurements of steady-state MPs in bacterial cells. Conventional electrode-based methods for the measurement of MP are not suitable for calibrating optical methods in small bacterial cells. While optical measurement based on Nernstian indicators have been successfully used, they do not provide absolute or precise quantification of MP or its changes. We present a novel, calibrated MP recording approach to address this gap. In this study, we used a fluorescence lifetime-based approach to obtain a single-cell-resolved distribution of the membrane potential and its changes upon extracellular chemical perturbation in a population of bacterial cells for the first time. Our method is based on 1) a unique VoltageFluor (VF) optical transducer, whose fluorescence lifetime varies as a function of MP via photoinduced electron transfer and 2) a quantitative phasor-FLIM analysis for high-throughput readout. This method allows MP changes to be easily visualized, recorded and quantified. By artificially modulating potassium concentration gradients across the membrane using an ionophore, we have obtained a Bacillus subtilis-specific MP versus VF lifetime calibration and estimated the MP for unperturbed B. subtilis cells to be -65 mV (in minimal salts glycerol glutamate [MSgg]), -127 mV (in M9), and that for chemically depolarized cells as -14 mV (in MSgg). We observed a population-level MP heterogeneity of ∼6-10 mV indicating a considerable degree of diversity of physiological and metabolic states among individual cells. Our work paves the way for deeper insights into bacterial electrophysiology and bioelectricity research.

Indexed as

Bacillus subtilisMembrane PotentialsCalibrationFluorescencePotassiumPotassium

Identifiers

PMID39798601
PMCPMC11835658

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.