--- _id: '503' abstract: - lang: eng text: Buffers are essential for diluting bacterial cultures for flow cytometry analysis in order to study bacterial physiology and gene expression parameters based on fluorescence signals. Using a variety of constitutively expressed fluorescent proteins in Escherichia coli K-12 strain MG1655, we found strong artifactual changes in fluorescence levels after dilution into the commonly used flow cytometry buffer phosphate-buffered saline (PBS) and two other buffer solutions, Tris-HCl and M9 salts. These changes appeared very rapidly after dilution, and were linked to increased membrane permeability and loss in cell viability. We observed buffer-related effects in several different E. coli strains, K-12, C and W, but not E. coli B, which can be partially explained by differences in lipopolysaccharide (LPS) and outer membrane composition. Supplementing the buffers with divalent cations responsible for outer membrane stability, Mg2+ and Ca2+, preserved fluorescence signals, membrane integrity and viability of E. coli. Thus, stabilizing the bacterial outer membrane is essential for precise and unbiased measurements of fluorescence parameters using flow cytometry. acknowledged_ssus: - _id: Bio acknowledgement: "We thank R Chait and M Lagator for sharing Bacillus subtilis CR_Y1 and pZS*_2R-cIPtet-Venus-Prm, respectively. We are grateful to T Pilizota and all members of the Guet lab for critically reading the manuscript. We also thank the Bioimaging facility at IST Austria for assistance using the FACSAria III system.\r\n\r\n" article_processing_charge: No author: - first_name: Kathrin full_name: Tomasek, Kathrin id: 3AEC8556-F248-11E8-B48F-1D18A9856A87 last_name: Tomasek orcid: 0000-0003-3768-877X - first_name: Tobias full_name: Bergmiller, Tobias id: 2C471CFA-F248-11E8-B48F-1D18A9856A87 last_name: Bergmiller orcid: 0000-0001-5396-4346 - first_name: Calin C full_name: Guet, Calin C id: 47F8433E-F248-11E8-B48F-1D18A9856A87 last_name: Guet orcid: 0000-0001-6220-2052 citation: ama: Tomasek K, Bergmiller T, Guet CC. Lack of cations in flow cytometry buffers affect fluorescence signals by reducing membrane stability and viability of Escherichia coli strains. Journal of Biotechnology. 2018;268:40-52. doi:10.1016/j.jbiotec.2018.01.008 apa: Tomasek, K., Bergmiller, T., & Guet, C. C. (2018). Lack of cations in flow cytometry buffers affect fluorescence signals by reducing membrane stability and viability of Escherichia coli strains. Journal of Biotechnology. Elsevier. https://doi.org/10.1016/j.jbiotec.2018.01.008 chicago: Tomasek, Kathrin, Tobias Bergmiller, and Calin C Guet. “Lack of Cations in Flow Cytometry Buffers Affect Fluorescence Signals by Reducing Membrane Stability and Viability of Escherichia Coli Strains.” Journal of Biotechnology. Elsevier, 2018. https://doi.org/10.1016/j.jbiotec.2018.01.008. ieee: K. Tomasek, T. Bergmiller, and C. C. Guet, “Lack of cations in flow cytometry buffers affect fluorescence signals by reducing membrane stability and viability of Escherichia coli strains,” Journal of Biotechnology, vol. 268. Elsevier, pp. 40–52, 2018. ista: Tomasek K, Bergmiller T, Guet CC. 2018. Lack of cations in flow cytometry buffers affect fluorescence signals by reducing membrane stability and viability of Escherichia coli strains. Journal of Biotechnology. 268, 40–52. mla: Tomasek, Kathrin, et al. “Lack of Cations in Flow Cytometry Buffers Affect Fluorescence Signals by Reducing Membrane Stability and Viability of Escherichia Coli Strains.” Journal of Biotechnology, vol. 268, Elsevier, 2018, pp. 40–52, doi:10.1016/j.jbiotec.2018.01.008. short: K. Tomasek, T. Bergmiller, C.C. Guet, Journal of Biotechnology 268 (2018) 40–52. date_created: 2018-12-11T11:46:50Z date_published: 2018-02-20T00:00:00Z date_updated: 2023-09-13T08:24:51Z day: '20' department: - _id: CaGu doi: 10.1016/j.jbiotec.2018.01.008 external_id: isi: - '000425715100006' intvolume: ' 268' isi: 1 language: - iso: eng month: '02' oa_version: None page: 40 - 52 publication: Journal of Biotechnology publication_status: published publisher: Elsevier publist_id: '7317' quality_controlled: '1' scopus_import: '1' status: public title: Lack of cations in flow cytometry buffers affect fluorescence signals by reducing membrane stability and viability of Escherichia coli strains type: journal_article user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 volume: 268 year: '2018' ...