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.

Molecular component distribution imaging of living cells by multivariate curve resolution analysis of space-resolved Raman spectra

“…In the past two decades, a number of publications have shown the successful application of Raman microspectroscopy to label-free molecular-level analysis of living cells and to discrimination of cell types. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] Although Raman spectra contain rich information on molecular structure, detailed interpretation of measured spectra is often difficult because of their complexity. Each Raman spectrum obtained from space-resolved mapping measurements is usually interpreted as a superposition of several spectral components of biomolecules, as well as a background and fluorescence.…”

Photobleaching of the resonance Raman lines of cytochromes in living yeast cells

“…The potential of Raman spectroscopy for characterization the cell activity was demonstrated recently by series of studies [20][21][22][23]. Another outstanding application of the Raman spectroscopy for cells is the studies of the Raman spectra of cytochromes [24][25][26][27][28][29][30][31][32][33].…”

Denoising Stimulated Raman Spectroscopic Images by Total Variation Minimization

“…Singular value decomposition has been widely used for noise reduction in spectroscopic images 35–37 . This method first factorizes the data matrix D into three matrix factors, D = USV T , where the unitary matrix U corresponds to an array of spectral vectors, S is a diagonal matrix composed of singular values, and V corresponds to an array of spatial vectors.…”