[Use of the fluorescence method to detect and quantitatively determine lipids in the cells of microorganisms]

Techniques have been developed for the detection and quantitative determination of lipids in the living cells of microorganisms (after their fixation by heating) using benzimidazole luminophores synthesized by Monocrystalreactive (USSR). When the yeast cells are stained by a luminophore, the latter is selectively bound to cellular lipids producing a brightly fluorescent complex. The intensity of fluorescence increases proportionally to an increase in the concentration of lipids in the microbial mass. The intensity of fluorescence of a microbial suspension is recorded using a spectrofluorimeter at the excitation and fluorescence maxima of 405 and 475 nm respectively. In order to assay the content of lipids in microorganisms which do not produce a homogeneous suspension, the luminophore bound to lipids is extracted from the cells with hot octane. The absolute content of lipids in the biomass is determined using a standard curve which shows the intensity of fluorescence of microorganisms and their octane extracts as a function of the lipid content in the cell.