Staining of Escherichia coli for flow cytometry: Influx and efflux of ethidium bromide

摘要: In an attempt to develop procedures for nucleic acid staining of bacteria clinical routine assays, the uptake ethidium bromide (EB) in wild-type Escherichia coli was studied using flow cytometry. Phosphate-buffered saline (PBS) containing EDTA or Tris significantly increased net EB compared PBS only. However, majority cells, reached a constant level that only few percent fully permeabilized apparently due activity metabolically driven efflux pump. When cells were exposed cold shock (0°C 30 min) presence EDTA, dye similar whereas it about half value PBS. given growth medium, split up into four subpopulations, with ranging from less than 1% value. As expected, metabolic inhibitors (Na-azide, 2-deoxy-D-glucose, and CCCP) reduced activity. fluorescence inhibited never exceeded more dead possibly reflecting conformational changes DNA structure as result cell death. © 1994 Wiley-Liss, Inc.