title: Spectrophotometric assay of yeast vitality using 2,3,5,6-tetramethyl-1,4-benzoquinone and tetrazolium salts.
abstract: A method for the spectrophotometric assay of yeast vitality was developed using 2,3,5,6-tetramethyl-1,4-benzoquinone and tetrazolium salts. The metabolic efficiency of 2,3,5,6-tetramethyl-1,4-benzoquinone by yeast cells was used as an index of yeast vitality. 2,3,5,6-Tetramethyl-1,4-benzoquinone was reduced to 2,3,5,6-tetramethyl-1,4-hydroquinone by yeast cells. Then, the superoxide anion radicals generated from O2 by reduction with 2,3,5,6-tetramethyl-1,4-hydroquinone under alkaline conditions reduced tetrazolium salts to formazan, which exhibited absorbance maxima at 440 nm. A linear relationship between the absorbance and viable cell density was obtained in the range of 1.0 x 10(5)-2.0 x 10(7) cells/ml for a sample solution. During the cultivation of yeast cells, the absorbance showed almost an anti-parallel change with that of glucose in yeast growth and fermentation, suggesting that the absorbance change reflected the vitality of yeast cells.
authors.affiliation: Biotechnology and Food Research Institute, Fukuoka Industrial Technology Center, Kurume 839-0861, Japan. tukatani@fitc.pref.fukuoka.jp
authors.forename: Tadayuki
authors.initials: T
authors.lastname: Tsukatani
authors.forename: Takahiro
authors.initials: T
authors.lastname: Oba
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ukeda
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Matsumoto
mesh_terms: D016227:Benzoquinones / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D012441:Saccharomyces cerevisiae / Q000502:physiology*; D013056:Spectrophotometry, Ultraviolet; D013778:Tetrazolium Salts / Q000737:chemistry*
chemical_list: D016227:Benzoquinones; D013778:Tetrazolium Salts; C034257:duroquinone