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1.
Mikrobiologiia ; 53(3): 489-94, 1984.
Article in Russian | MEDLINE | ID: mdl-6431241

ABSTRACT

The effect of dehydration on the morphology and fine structure of conidia was studied with the atmospheric and collection strains of Aspergillus niger and Penicillium chrysogenum. Dehydration did not cause changes in the structure of most conidia. However, destructive changes in the conidial wall and membrane were found in some conidia. The cytological changes of conidia were either reversible or irreversible, which determined their survival rate during dehydration.


Subject(s)
Air Microbiology , Aspergillus niger/physiology , Penicillium chrysogenum/physiology , Penicillium/physiology , Aspergillus niger/ultrastructure , Desiccation , Penicillium chrysogenum/ultrastructure , Spores, Fungal/physiology , Spores, Fungal/ultrastructure
2.
Mikrobiologiia ; 52(6): 902-8, 1983.
Article in Russian | MEDLINE | ID: mdl-6422211

ABSTRACT

The object of this work was to study cytological changes caused by periodic freezing-thawing in the conidia of the fungi Aspergillus niger and Penicillium chrysogenum isolated from the mesosphere as well as in the conidia of the same species taken from the collection of microorganisms. The conidia from the mesosphere were found to be highly resistant to the treatment. As was shown by electron microscopy, the outer "backbone" layer of the spore envelope broke down and the membranes of the plasmalemma stratified after ten cycles in A. niger and P. chrysogenum. The percentage of conidia with the damaged ultrastructural organization was higher in mutants of these cultures.


Subject(s)
Air Microbiology , Aspergillus niger/physiology , Penicillium chrysogenum/physiology , Penicillium/physiology , Periodicity , Aspergillus niger/ultrastructure , Freezing , Microscopy, Electron , Penicillium chrysogenum/ultrastructure
3.
Mikrobiologiia ; 50(3): 508-14, 1981.
Article in Russian | MEDLINE | ID: mdl-7024748

ABSTRACT

The techniques of light and electron microscopy were used to study structural changes in Candida lipolytica cells related to limitation of their growth and a nitrogen source in medium with glucose and hexadecane and transition of the culture to the production of citric acids. Changes in the content of protein in the cell and in the activities of enzymes of the citrate and glyoxylate cycles located in mitochondria and peroxysomes of the yeast were investigated at the same time. The results characterizing cytological changes in the cell of C. lipolytica in the conditions of citric acid biosynthesis fit in well with the data on protein content and enzyme activities in the cells obtained by biochemical analysis. The transition of the yeast cells to the overproduction of citric acids has been shown to be related to profound rearrangements of the cell: the inhibition of protein synthesis; changes in the structure of the cytoplasm; the appearance of vacuoles of an irregular shape, often in contact with the mitochondria; changes in the mitochondrial and peroxysomal apparatus; the accumulation of lipids. It has been demonstrated once again that the peroxysomal apparatus of the yeast cell has a relationship with the metabolism of n-alkanes.


Subject(s)
Candida/cytology , Citrates/biosynthesis , Candida/metabolism , Citric Acid , Culture Media , Microscopy, Electron , Microscopy, Fluorescence , Microscopy, Phase-Contrast
4.
Mikrobiologiia ; 47(6): 1030-6, 1978.
Article in Russian | MEDLINE | ID: mdl-570633

ABSTRACT

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.


Subject(s)
Ascomycota/ultrastructure , Candida/ultrastructure , Catalase/metabolism , Microbodies/enzymology , Organoids/enzymology , Pichia/ultrastructure , Candida/enzymology , Histocytochemistry , Microscopy, Electron , Pichia/enzymology , Species Specificity
5.
Z Allg Mikrobiol ; 18(3): 203-7, 1978.
Article in English | MEDLINE | ID: mdl-358621

ABSTRACT

Virus-like particles containing electron dense cores are seen in thin sections of intact and degenerated cells of a thermosensitive (ts) strain of Candida tropicalis. A particulate fraction not present in wild-type cells has been isolated from the ts cells disrupted by pressure. The particles are 80-120 nm in diameter. Empty particles with a central cavity are observed. The method of infecting mating pairs of Saccharomyces cerevisiae by partially purified particles is described.


Subject(s)
Candida/ultrastructure , Plant Viruses/isolation & purification , Saccharomyces cerevisiae/ultrastructure , Plant Viruses/growth & development , Plant Viruses/ultrastructure
6.
Mikrobiologiia ; 46(5): 835-45, 1977.
Article in Russian | MEDLINE | ID: mdl-340851

ABSTRACT

Yeast peroxisomes (microbodies) were studied, particularly with yeast methylotrophs, using light-optical microscopy, viz. intravitam phase- and anoptral-contrast microscopy, with cytochemical as well as fixed and stained objects. The data obtained were compared with cytochemical as well as fixed and stained objects. The data obtained were compared with other evidence that we had gained on methylotrophs studied by electron microscopy and with the results obtained by investigating the peroxisomes of yeast cultures grown on nutrient containing other carbon sources. The activity of exocatalase and endocatalase, the enzymes characteristic of peroxisomes, was assayed at different growth phases of yeast methylotrophs and was found to be correlated with the cycle of development of peroxisomes. The content of biotin and inositol and its dynamics were studied in the methylotroph cells. Possible origin of peroxisomes is discussed as well as their development and the mechanism of degradation. A close contact and functional relationship have been established between peroxisomes and mitochondria.


Subject(s)
Microbodies/physiology , Organoids/physiology , Saccharomyces cerevisiae/physiology , Biotin/metabolism , Catalase/metabolism , Inositol/metabolism , Microbodies/ultrastructure , Mitochondria/physiology , Saccharomyces cerevisiae/ultrastructure
7.
Mikrobiologiia ; 45(6): 1113-4, 1976.
Article in Russian | MEDLINE | ID: mdl-1034867

ABSTRACT

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.


Subject(s)
Microbodies , Mitosporic Fungi/growth & development , Organoids , Rhodotorula/growth & development , Mitochondria , Mitosporic Fungi/ultrastructure , Morphogenesis , Rhodotorula/ultrastructure
8.
Mikrobiologiia ; 45(5): 844-51, 1976.
Article in Russian | MEDLINE | ID: mdl-1034194

ABSTRACT

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.


Subject(s)
Alkanes/metabolism , Candida/ultrastructure , Mitosporic Fungi/ultrastructure , Rhodotorula/ultrastructure , Adaptation, Physiological , Candida/metabolism , Cell Wall/ultrastructure , Mitosporic Fungi/metabolism , Organoids/ultrastructure , Rhodotorula/metabolism , Species Specificity
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