title: Nucleic acid fluorochromes and flow cytometry prove useful in assessing the effect of chlorination on drinking water bacteria.
abstract: Flow cytometry (FCM), combined with staining using two fluorochromes (propidium iodide, PI, or SYBR Green II RNA gel stain, SYBR-II), was used to assess nucleic acid injuries to chlorinated drinking water bacteria. Highly fluorescent SYBR-II-stained bacteria were converted to bacteria with low fluorescence after chlorination. PI staining of bacteria exposed to different doses of chlorine showed membrane permeabilisation ([Cl2] < 0.2 mg L(-1)) and nucleic acid damage at higher doses ([Cl2] > 0.3 mg L(-1)). Above a threshold dose (between 1.5 and 3 mg Cl2 L(-1)), nucleic acids appeared severely damaged and incapable of being stained by PI or SYBR-II. These results constitute evidence that FCM is a promising tool for assessing drinking water bacteria injuries and for controlling chlorine disinfection efficiency much more rapidly than the standard sensitive but time-consuming heterotrophic plate count method.
authors.affiliation: Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, LCPME UMR 7564 CNRS-UHP, Pôle de l'Eau-15, F-54500 Vandoeuvre-lès-Nancy, France.
authors.forename: Meng-Huot
authors.initials: MH
authors.lastname: Phe
authors.forename: Manuel
authors.initials: M
authors.lastname: Dossot
authors.forename: Hélène
authors.initials: H
authors.lastname: Guilloteau
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Block
mesh_terms: D001419:Bacteria / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000187:drug effects; D002713:Chlorine / Q000633:toxicity*; D004396:Coloring Agents; D005434:Flow Cytometry; D005456:Fluorescent Dyes; D009696:Nucleic Acids / Q000187:drug effects*; D009930:Organic Chemicals; D011419:Propidium; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods; D014881:Water Supply
chemical_list: D004396:Coloring Agents; D005456:Fluorescent Dyes; D009696:Nucleic Acids; D009930:Organic Chemicals; C098798:SYBR Green II; D011419:Propidium; D002713:Chlorine