[Luminescence microscopy determination of the survival of yeasts after dehydration]. / O liuminestsentno-mikroskopicheskom opredelenii vyzhivaemosti drozhzhevykh organizmov posle obezvozhivaniia.

The technique of luminescent microscopy can be used to determine the survival rate of yeast organisms dehydrated by the convective method. If the cells were subjected to more severe extreme actions, the technique should be combined with the direct microscopy to follow the growth of reactivated organisms and to count the number of microcolonies being formed. The authors propose to classify the state of living organisms after the action of sublethal factors basing on the ability of cells to grow after reactivation.

[Localization of secreted ribonuclease in the cell walls of Aspergillus clavatus]. / Lokalizatsiia sekretiruemoi ribonukleazy na kletochnykh stenkakh Aspergillus clavatus.

The indirect technique of fluorescent antibodies was used to detect exocellular ribonuclease of Aspergillus clavatus. The cell walls were shown to have regions responsible for the enzyme excretion.

[Determination of primary amines and protein by using fluorescamine in microorganism suspensions]. / Opredelenie pervichnykh aminov i belka c pomoshch'iu fluoreskamina v suspenziiakh mikroorganizmov.

The paper describes a fluorimetric technique for determining the overall amount of primary amines and protein using fluorescamine directly in suspensions of yeast and bacterial microorganisms. The optimal conditions are selected for the reaction. The technique is highly sensitive and has an advantage over biochemical methods when one has to make many assays of amine containing compounds in biological material. The technique can find wide application in industrial practice.

[Use of the fluorescence method to detect and quantitatively determine lipids in the cells of microorganisms]. / Ispol'zovanie fluorestsentnogo metoda dlia vyiavleniia i kolichestvennogo opredeleniia lipidov v kletkakh mikroorganizmov.

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.

[Formation and degradation of peroxisomes in yeasts]. / O vozniknovenii i degradatsii peroksisom u drozhzhevykh organizmov.

The formation, development and degradation of peroxisomes were studied directly in growing yeast-methylotrophs under the microscope using anoptral and phase contrast. The degradation of peroxisomes was caused by their degeneration and dislocation to the central vacuole of the yeast cell. A fluorescent-microscopic technique was elaborated for detecting selectively the crystals of catalase in the cells. As was shown by intravitam studies, electron microscopy and cytochemistry, peroxisomes are directly connected with the central vacuole of the cell, enzymes being transferred from the former into the latter. Experiments conducted with different cultures have demonstrated that the high activity of exocatalase is typical of methylotrophic yeast organisms. The highest activity that was exhibited for a long period of time was found in Torulopsis molischiana.

[Possible participation of mitochondria in formation of peroxisomes in yeasts]. / O vozmozhnom uchastii mitokhondrii v obrazovanii peroksisom u drozhzhevykh organizmov

The origin of peroxisomes in yeast organisms is still unknown. These organelles are believed to be formed, similar to animal cells, from the endoplasmatic reticulum. However, this has not been confirmed directly. Peroxisomes are often found to be in contact with channels of the endoplasmatic reticulum and, in our experiments, with mitochondria of yeast organisms, especially those which utilize oleic acid, n-alkanes and methanol as a sole source of carbon. In Rhodotorula, peroxisomes are characterized by the same "bean" configuration and paired arrangement imitating "copulation" as mitocondria. In Kloeckera boidinii, a mitochondrion was transformed into a peroxisome and cristae were lost. A part of the peroxisome still possessed a double membrane typical of mitochondria while another part had a single membrane characteristic of peroxisomes. Further studies are being carried out in order to find if this is a general relationship or one of possibilities.

[Cytological mechanisms involved in assimilation of n-alkanes by yeasts]. / Tsitologicheskie mekhanizym assimiliatsii drozhzhevymi organizmami n-alkanov

The paper describes cytological mechanism of adaptation of yeasts to assimilation of aliphatic hydrocarbons added to a growth medium as a sole source of carbon. The process was studied by light optical and electron microscopy, employing fluorescent labelling and electron microscopy contrasting. Two types of yeasts were found, which differed by the response of the cell walls to hydrocarbons: those that formed "channels" and those that did not form them. Cytological response to hydrocarbon assimilation was detected also in the mitochondria and canals of the endoplasmic reticulum. Components of the Golgi apparatus may also participate in this process, in particular, in formation of peroxisomes (microbodies). Close contacts of the yeast cells with the hydrocarbon being assimilated is important; assimilation may start in a close vicinity of the cell walls. The rate of flavin production by Candida tropicalis 303 IBFM increases during growth on solid paraffins, beginning with C20-paraffin.

[Increased flavinogenesis in 1 of the strains of Candida tropicalis]. / O povyshennom flavinogeneze u odnogo iz shtammov Candida tropicalis

Candida tropicalis IBFM 303 is capable of the active production and liberation of flavins during the oxidation of solid paraffins with the carbon chain consisting of 20 carbon atoms and more. Unlike other known strains, this strain does not accumulate considerable amounts of the vitamin neither on media containing liquid n-paraffins not on media with glucose, even under the conditions of iron deficiency.

[Intravital accumulation of acriflavine in mitochondria of yeast organisms]. / Prizhiznennoe nakoplenie akriflavina v mitokhondriiakh drozhzhevykh organiznov

Acriflavine, a fluorochrome of the acridine series, inducing cytoplasmic mutations in yeast organisms, at low concentrations (0.25 to 2.50 mcg/ml) in the growth medium, is selectively accumulated in the mitochondria in which it forms complexes with nucleic acids. This binding of acriflavine to nucleic acids in the mitochondria has almost no effect on the cell viability though their respiratory activity decreases at these concentrations by 70 percent, and the activity of fermentation increases by 15 to 20 percent.