title: Autofluorescence of Toxoplasma gondii and Neospora caninum cysts in vitro.
abstract: Autofluorescence of Toxoplasma gondii and Neospora caninum was studied by fluorescence microscopy during their differentiation from tachyzoites to bradyzoites in vitro using Vero as host cells. Stage conversion into bradyzoites and cysts was confirmed by immunofluorescent microscopy and Western blot analysis using SAG1- and BAG1-specific antibody, respectively. From day 4 postinfection (PI), pale blue autofluorescence of the bradyzoites and tissue cysts was observed with UV light at 330-385 nm, which coincided with the onset of cyst development. This autofluorescence under UV light of bradyzoites and tissue cysts increased in intensity from days 8 to 10 PI. In contrast to the autofluorescence shown by bradyzoites and cysts, tachyzoites and parasitophorous vacuoles containing tachyzoites never autofluoresced at any time examined. Autofluorescence of the cystic stages was of sufficient intensity and duration to allow the detection of cysts and bradyzoites of T. gondii and N. caninum. In this study, we describe for the first time the autofluorescence properties of in vitro-induced bradyzoites and cysts of T. gondii and N. caninum.
authors.affiliation: Department of Cell and Molecular Biology, University of Technology, Sydney, Gore Hill, New South Wales 2065, Australia.
authors.forename: Ying
authors.initials: Y
authors.lastname: Lei
authors.forename: Mary
authors.initials: M
authors.lastname: Davey
authors.forename: John
authors.initials: J
authors.lastname: Ellis
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000913:Antibodies, Protozoan / Q000276:immunology; D000953:Antigens, Protozoan / Q000276:immunology; D000954:Antigens, Surface / Q000276:immunology; D015153:Blotting, Western; D002522:Chlorocebus aethiops; D006360:Heat-Shock Proteins / Q000276:immunology; D008856:Microscopy, Fluorescence; D018688:Neospora / Q000254:growth & development / Q000276:immunology / Q000502:physiology*; D015800:Protozoan Proteins / Q000276:immunology; D012692:Serial Passage; D014122:Toxoplasma / Q000254:growth & development / Q000276:immunology / Q000502:physiology*; D014709:Vero Cells
chemical_list: D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D000954:Antigens, Surface; C106179:BAG1 protein, Toxoplasma; D006360:Heat-Shock Proteins; D015800:Protozoan Proteins; C047168:SAG1 antigen, Toxoplasma; C115390:SAG1 protein, Neospora caninum