title: Evaluation of the redox dye 5-cyano-2,3-tolyl-tetrazolium chloride for activity studies by simultaneous use of microautoradiography and fluorescence in situ hybridization.
abstract: Three microscopic in situ techniques were used simultaneously to investigate viability and activity on a single-cell level in activated sludge. The redox dye 5-cyano-2,3-tolyl-tetrazolium chloride (CTC) was compared with microautoradiography (MAR) and fluorescence in situ hybridization (FISH) to indicate activity of cells in Thiothrix filaments and in single floc-forming bacteria. The signals from MAR and FISH correlated well, whereas only 65% of the active Thiothrix cells and 41% of all single cells were detectable by CTC reduction, which mainly targeted the most active cells.
authors.affiliation: Department of Environmental Engineering, Aalborg University, DK-9000 Aalborg, Denmark.
authors.forename: Jeppe Lund
authors.initials: JL
authors.lastname: Nielsen
authors.forename: Marilena
authors.initials: M
authors.lastname: Aquino de Muro
authors.forename: Per Halkjaer
authors.initials: PH
authors.lastname: Nielsen
mesh_terms: D001345:Autoradiography; D005456:Fluorescent Dyes / Q000378:metabolism*; D020563:Gammaproteobacteria / Q000166:cytology / Q000378:metabolism; D017404:In Situ Hybridization, Fluorescence; D010084:Oxidation-Reduction; D012722:Sewage / Q000382:microbiology; D013778:Tetrazolium Salts / Q000378:metabolism*
chemical_list: D005456:Fluorescent Dyes; D012722:Sewage; D013778:Tetrazolium Salts