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M V Gusev

Publications and source records attributed to M V Gusev.

At least 37 records · Page 2Linked to original sources
PubMedDate not supplied

[Characteristics of the cellular ultrastructural organization of the chemoheterotrophic blue-green alga, Chlorogloea fritschii].

Cellular ultrastructural organization was compared in photoautotrophic and chemoheterotrophic cultures of the blue-green alga Chlorogloea fritschii Mitra. Cells at the fourth stage of the life cycle of the culture in the phase of growth were studied in both cases. The structure of thylakoids was the main object of investigation. The cells of investigation. The cells of Chl. fritschii had a peculiar organization when they were cultivated in the dark on a medium containing glucose as a source of carbon and energy. These cells differed from photosynthetic cells by the structure of the cell wall, cytoplasm, and thylakoids. The cell wall can be entirely or partly absent. The cytoplasm has a lower electron density. The cell wall can be entirely or partly absent. The cytoplasm has a lower electron density. The thylakoids are arranged more random and less compact than in the cells grown in the light. Membranes which form these thylakoids, under identical conditions of fixation, contrasting and microscopy of preparations, look usually as one-layered rather than three-layered. Apparently, the ultrastructure of thylakoids on Chl. fritschii reflects the specificity of energy mechanisms that function in cells in the light and in the dark.

Culture Media↗
PubMedDate not supplied

[Electron microscopic study of thylakoid structure in cyanobacteria].

Two or three thylakoids can be detected in Synechococcus elongatus, strain 58, and Plectonema boryanum if sections are successful. Peripheral thylakoids sometimes seem to be connected with the cytoplasmic membrane. Partitions and septa, as well as small electron-dense granules typical of cells which underwent lysis, are found in the intrathylakoidal space. Branching of thylakoids is described. Particles 16 and 11 nm in size whose possible nature is discussed can be discerned on the fracture faces. Phycobilisomes have not been discovered by the technique of freeze-etching.

Cyanobacteria↗
PubMedDate not supplied

[Changes in the ultrastructures of Anacystis nidulans cells at different temperatures].

If the cells of the blue-green alga Anacystis nidulans are put in the unfavourable conditions, the pairs of photosynthetic membranes separate, vacuoles are formed within thylakoids, and degradation of the photosynthetic apparatus occurs the earlier the sooner photosynthetic electron transport stops functioning: after 7--9 days in the dark, after 7--10 days in the light at 5 degrees C, after 5--7 days at 45 degrees C. If the cells are incubated at 5 and 45 degrees C, they become longer and form rods upto 10--12 mcm in length; at 45 degrees C, degradation takes place and the cell contents separate. The stationary phase of growth in the optimal conditions at 37 degrees C takes more time and the cells are degraded only after 45 days. If the temperature is lowered to 20 degrees C in the light, the cells remain viable for a long time and are degraded only after 60 days. In these conditions, invaginations of photosynthetic lamellae appear in the living cells, and the activity of TTC reduction in the light remains high for a long period of time. The cell wall remains intact upon degradation in remains high for a long period of time. The cell wall remains intact upon degradation in all the variants. Pigments are not destroyed both at a high (45 degrees C) and low (5 degrees C) temperature longer in the dark than in the light; therefore, photodestruction is involved in degradation of the lamellar apparatus in the light. The order in which pigments decompose differs depending on the conditions: chlorophyll is the first to be destroyed at 5 degrees C, phycocyanin at 45 degrees C, chlorophyll and phycocyanin at 37 degrees C; the rate of degradation of all pigments is almost the same at 20 degrees C. Apparently, additional pigments play different role in the processes of degradation occurring in the light.

Cyanobacteria↗
PubMedDate not supplied

[Effect of lysozyme, ethylenediaminetetraacetate, magnesium and mannittol on spheroplast formation in Anacystis nidulans].

Three periods (the lag period and periods of intensive and decelerated spheroplast formation) can be detected in the action of lysozyme on the cells of Anacystis nidulans; this seems to be due to peculiarities in the cell wall structure of the cyanobacterium and heterogeneity of the culture. EDTA at concentrations of 0.175--0.7 mM has effect on the duration of the lag period but increases the rate of spheroplast formation during the subsequent periods. However, the action of EDTA in complex with lysozyme for 3 hours causes lysis of some of the spheroplasts being formed. The concentration of mannitol below 0.4 M decreases the yield of spheroplasts. The level of intact spheroplasts prepared from A. nidulans suggests that at least part of them is capable of reversing into whole cells.

Cyanobacteria↗
PubMedDate not supplied

[Characteristics of infection of plants and their cultured tissue with cyanobacterial-bacterial symbiotic associations].

The infection of tobacco, nightshade, rice plants, and their tissue cultures with the cyanobacteria-bacteria symbiotic associations (CBSA) isolated from natural syncyanoses (the ferns Azolla pinnata and Azolla sp. and the cycad Encephalartos ferox) was studied. The inoculation of the intact plants or their cuttings with CBSA led to the colonization of the plant roots, stems, and leaves by cyanobacteria and their bacterial symbionts (referred to as satellite bacteria, SB). The sites of the long-term contact of plant organs with cyanobacteria were characterized by the formation of copious slime. On the roots of infected plants, one could observe the callus growth of cortical parenchyma cells and the formation of pseudonodules, in which SB cells gradually accumulated. In mixed cultures of plant callus tissues and the CBSA isolated from the ferns A. pinnata and Azolla sp., the callus tissue specifically influenced the growth of the CBSA components, causing (depending on the plant species and strain) either their balanced growth, or their cyclic growth, or the predominant growth of one of the CBSA components (either cyanobacteria or satellite bacteria). This phenomenon is proposed to be used for the dissociation of stable multicomponent natural symbiotic complexes and the selection of their particular components.

Culture Techniques↗
PubMedDate not supplied

[Morphologic heterogeneity under different conditions of living and destruction in Anabaena variabilis cyanobacteria].

The proportion between various morphological forms of the cyanobacterium Anabaena variabilis was studied under different conditions of its growth and destruction. When the cells lost viability at the stationary phase of cultural growth under the optimal conditions of illumination (1500--2000 lx), in the dark or when nitrogen was deficient, the filaments became shorter (4 to 2.2 cells per filament on the average), the cells larger, 4.5x6 microns). Under the conditions of nitrogen deficiency, the content of phycocyanin sharply decreased as well as that of chlorophyll. "Aging" under the conditions of optimal illumination was accompanied with "weighting" of the cells at the prolonged stationary phase and a gradual decrease in the content of phycocyanin and chlorophyll. When the cells were exhausted in the dark, the content of protein, RNA and phycocyanin decreased while that of chlorphyll hardly changed for a considerably long period of time. The most versatile morphological heterogeneity, when the cells were rapidly destroyed under the conditions of high light intensity, was as follows: both larger and more spherical as well as smaller and longer than in the control cells was found and catenuate cells were detected. The colour of the culture was light-brown or blue. When grown in a medium containing aspartic acid, the culture consisted of long filaments (ca. 18 cells per fragment instead of 4 cells in the control).

Chlorophyll↗
PubMedDate not supplied

[Blooming and destruction of cyanobacteria in the drainage bassin of the hydrogen sulfide spring of Staraya Matsesty].

The growth of cyanobacteria belonging to the genera Oscillatoria and Anabaena (up to 2.1 x 10(7) filaments per 1 g of wet sample) was found in a water reservoir with a high content of sulfides (up to 9 mM) in Staraya Matsesta throughout the year. The spots of Oscillatoria are located in the spring in more illuminated areas as compared to Anabaena. In the spring, not only spots of actively growing cells were detected, but also accumulations of Oscillatoria cells being destroyed (blue spots). Water-bloom spots in which Oscillatoria prevailed can transform into the spots of Anabaena. The main accompanying forms in the spots of Anabaena are long thin filaments of the flexibacterial type while short rods are found in the spots where Oscillatoria predominates. Heterotrophic enteric bacteria (48 x 10(4) cells per 1 g), Bacillus, Pseudomonas, and coryneform bacteria were also detected. Green bacteria (Chlorobium) and nonsulfur purple bacteria (Rhodomicrobium) were present in small quantities (16 x 10(3) cells per 1 g) as well as sulfate-reducing bacteria (5--15 x 10(2) cells per 1 g) and thiobacilli (40--60 cells per 1 g). In the spring, stones were covered with pink spots of spherical motile purple bacteria and with yellow-green spots of filamentous green bacteria. The cyanobacteria from the spots are capable of oxygenated photosynthesis. Fixation of CO2 by them in situ is 0.08 mcg per 1 g of dry sample per hour or 0.06 mcg per 10(6) cells per hour, and is inhibited by 10(-5) M DCMU by 70%.

Cyanobacteria↗
PubMedDate not supplied

[Superoxide dismutase in Clostridium butyricum spores].

Superoxide dismutase was found for the first time in the spores of the anaerobic bacterium Clostridium butyricum. The prosthetic group of the enzyme was shown to contain iron. The enzyme was demonstrated to be highly thermostable.

Clostridium↗
PubMedDate not supplied

[Electron microscopic study of dark and photo-oxidative degradation of the blue-green alga Anabaena variabilis].

Changes in the cell ultrastructure were studied during incubation of the obligate phototrophic blue-green alga Anabaena variabilis in the dark for a long time. The cells lost viability though their cell wall and cytoplasmic membrane were preserved; however, certain regions of the mureine layer were thickened in some cells. The membranes of the photosynthetic apparatus separate forming intrathylakoid spaces and the cytoplasm density decreases revealing phycobilisomes. During incubation in the dark for a long time, polyglucoside alpha-granules in the cytoplasm disappear, polyhedral bodies are preserved, and numerous large granules of average electron density and unknown nature appear. Transfer of the culture from the dark to the light when the cells are losing their viability results in intensive destruction of the thylakoids. Loss of viability by the cells of Anabaena variabilis in the dark is supposed to be due to irreversible damages of the membranes of the photosynthetic apparatus in these conditions.

Cell Membrane↗
PubMedDate not supplied

[Age-related changes in the ultrastructure of Anabaena variabilis cells].

The growth and death of the obligate phototrophic cyanobacterium Anabaena variabilis Kütz, strain Lefevre, were studied under stationary conditions in the light. Each growth stage can be characterized by physiological and ultrastructural peculiarities. The following changes have been found in the cells with aging: the rate of oxygen evolution decreases, the photosynthetic lamellae untwist and separate with the formation of intrathylakoid vacuoles, the number of inclusions increases. Irreversible vesiculation of the parachromatophore was observed during the death of the cells. Lysis of the cells was found to be different in the light and in the dark.

Cyanobacteria↗
PubMedDate not supplied

[Epiphase carotenoids of the blue-green alga Anabaena variabilia].

Epiphase carotenoids were studied in the cells of the obligate phototrophous blue-green alga Anabaena variabilis. Ten pigment zones were detected by column chromatography on alumina and by TLC on cellulose and Silufol UV-254 plates. TLC in the B layer and paper chromatography did not reveal all pigment zones obtained on a column. The data of TLC on cellulose and on Silufol plates confirmed the purity and individual character of the fractions obtained on a column. These data showed also that the pigments obtained upon the separation of the extract on a column were not the products of its interaction with an active adsorbent. Absorption spectra of the isolated pigments were determined in various solvents, and speculations were made concerning the structure of the carotenoids.

Carotenoids↗
PubMedDate not supplied

[Hydrocarbon-oxidizing microflora of uncontaminated seawater].

The distribution of hydrocarbon-oxidizing microflora in noncontaminated sea waters was studied in the northern region of the Pacific Ocean in the vicinity of the Copper Island. The total number of microorganisms was assayed as well as the number of heterotrophic, oligocarbophilic and hydrocarbon-oxidizing microorganisms. Oligocarbophilic bacteria were the most abundant group (from 120 to 24,000 cells per 1 ml), and predominated in 12 stations among 23. The number of heterotrophic organisms was not great and did not exceed 200 cells per 1 ml in 13 stations. A solid medium with an oil product (1%) which was used to determine the number of hydrocarbon-oxidizing bacteria gave overstated results due to the growth of oligocarbophilic forms that could survive in the presence of high hydrocarbon concentrations in the medium. A silica gel medium with an oil product is recommended. Despite the absence of oil contaminations in littoral waters, hydrocarbon-oxidizing bacteria were found in all samples and their content was high in some stations. This can be accounted for by the variety of nutrient requirements of these microorganisms and, apparently, by the presence in water of high molecular weight aliphatic lipids inding the capacity to oxidize hydrocarbons. Organisms belonging to the genera Mycobacterium and Arthrobacter prevailed among hydrocarbon-oxidizing bacteria.

Hydrocarbons↗