title: Photobleaching of the "Raman spectroscopic signature of life" and mitochondrial activity in rho- budding yeast cells.
abstract: Raman spectra of mitochondria in single living budding yeast (zygote of Saccharomyces cerevisiae and Saccharomyces bayanus) cells have been measured and compared for two types of tetraploid strains, the wild-type strain and the rho- strain. The "Raman spectroscopic signature of life", a strong Raman band at 1602 cm(-1) that sharply reflects the mitochondrial activity, has been found in both of the two strains with similar intensities. This signature showed photobleaching under irradiation of the 632.8 nm line of a He-Ne laser, only for the rho- strain. The photobleaching recovered by keeping the cell in the dark for two hours without laser irradiation. These findings indicate that the molecular species that gives rise to the 1602 cm(-1) band is an intermediate formed and accumulated during the metabolic cycle and that it absorbs at 632.8 nm to undergo photodecomposition. We also found a number of weak Raman bands in the 400-1200 cm(-1) region that show the same temporal behaviors as that of the 1602 cm(-1) band by an SVD analysis of time-resolved Raman spectra. Several new pieces of information on the origin of the "Raman spectroscopic signature of life" have thus been obtained.
authors: Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors: Chikao
authors: C
authors: Onogi
authors: Hiro-O
authors: HO
authors: Hamaguchi
mesh_terms: D008928:Mitochondria / Q000378:metabolism*; D038761:Photobleaching; D011123:Polyploidy; D012440:Saccharomyces / Q000235:genetics / Q000378:metabolism*; D013059:Spectrum Analysis, Raman