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bioRxiv · 10.1101/2022.06.22.497132

Cytoplasmic membrane thinning observed by interfacial dyes is likely a common effect of bactericidal antibiotics

Dubey, A. K.·Verma, T.·Sardana, D.·Khamari, B.·Alam, P.·Eswarappa, P. B.·Sen, S.·Nandi, D.
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Abstract

The lipid membrane is a fundamental part of life. However, the effects of different stresses on membranal integrity and physiology are less understood. Using novel 4-aminophthalimide-based membrane-specific dyes (4AP-Cn: n is carbon chain-length), aided with confocal microscopy, fluorescence spectroscopy, molecular dynamics simulations, and flow cytometry, we have studied stress-mediated changes in E. coli membranes. By exploiting the depth-dependent positioning and subsequent environmental sensitivity of the dyes, we have proposed a measure of antibiotic-induced membrane damage: the fluorescence Peak Maxima Difference (PMD) between 4AP-C9 and 4AP-C13. The ROS-influenced PMD quantifies cytoplasmic membrane thickness and measures sensitivity against most bactericidal antibiotics, depending upon the extent of lipid peroxidation. Importantly, we have verified this observation using antibiotic-sensitive and resistant clinical isolates of E. coli and ESKAPE pathogens like K. pneumoniae and Enterobacter spp. This study underscores the role of antibiotic-induced membrane changes; a critical issue given the increasing global antimicrobial resistance.

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Dubey, A. K., Verma, T., Sardana, D., Khamari, B., Alam, P., Eswarappa, P. B., Sen, S., Nandi, D.. 2022-06-22. Cytoplasmic membrane thinning observed by interfacial dyes is likely a common effect of bactericidal antibiotics. https://doi.org/10.1101/2022.06.22.497132

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