title: Flow cytometric determination of endocytosis of viable labelled Legionella pneumophila by Acanthamoeba palestinensis.
abstract: Endocytosis of fluorescently labelled cells of Legionella pneumophila (L. pneumophila) by free-living Acanthamoeba palestinensis (A. palestinensis) has been studied using flow cytometry. L. pneumophila cells were labelled with CM-DiI, a lipophilic fluorescent probe under conditions that did not modify viability. Coculturing the bacteria with amoebae was accompanied by rapid endocytosis; after 5 min, 90% of the amoebae had internalized bacteria. This percentage remained unchanged during further coculture, but the number of bacteria ingested per amoeba increased. Moreover, the number of ingested bacteria was found to be dependent on the size of the amoeba. The validity of the internalization analyzed by flow cytometry was confirmed by observation using epifluorescence and phase contrast microscopy. CM-DiI labelling associated with flow cytometry provides a very valuable technique for the determination of bacteria endocytosis by free-living amoeba.
authors.affiliation: Laboratoire de Toxinologie Bacterienne, Institut de Bacteriologie de la Faculte de Medecine, Universite Louis Pasteur, Strasbourg, France.
authors.forename: C
authors.initials: C
authors.lastname: Harf
authors.forename: S
authors.initials: S
authors.lastname: Goffinet
authors.forename: O
authors.initials: O
authors.lastname: Meunier
authors.forename: H
authors.initials: H
authors.lastname: Monteil
authors.forename: D A
authors.initials: DA
authors.lastname: Colin
mesh_terms: D000048:Acanthamoeba / Q000166:cytology* / Q000502:physiology; D000818:Animals; D002232:Carbocyanines / Q000737:chemistry; D002469:Cell Separation; D004705:Endocytosis / Q000502:physiology*; D005434:Flow Cytometry; D005456:Fluorescent Dyes; D016952:Legionella pneumophila / Q000166:cytology* / Q000502:physiology; D008856:Microscopy, Fluorescence; D008858:Microscopy, Phase-Contrast
chemical_list: C101089:CM-DiI; D002232:Carbocyanines; D005456:Fluorescent Dyes