[Endospore formation by Streptomyces avermitilis in submerged culture].

The capability of streptomycetes to form endospores during their life cycle was studied in submerged cultures of Streptomyces avermitilis. Submerged S. avermitilis spores were most intensely formed (1) during the culture development cycles on synthetic medium CP1 with glucose under phosphate limitation, and (2) in autolysing cell suspensions of high density obtained by tenfold concentration of a stationary-phase culture grown in a synthetic medium resuspended in phosphate buffer (pH 7.2) with 0.2% CaCl2. Endospores of S. avermitilis formed in submerged cultures shared the major characteristics of specialized microbial resting forms: heat resistance, resistance to lysozyme, ability to pertain to the main species-defining features, and ultrastructural organization characteristic of endospores. They can be considered a resting form of streptomycetes alternative to the spores formed exogenously on aerial mycelium in a surface culture.

[Degradation of machine oil by nocardiform bacteria]. / Degradatsiia neftianykh masel nokardiopodobnymi bakteriiami.

Gas liquid chromatography (GLC) was used for the first time to screen for machine oil-degrading microorganisms. Oil degradation was evaluated from the microorganism respiratory activity during the utilization of oil as the sole carbon and energy source. The results are consistent with those obtained by the conventional weighing method. Substrate specificity of the active strains with respect to different machine oils was studied. Bacterial communities exhibited the highest activity, whereas a Rhodococcus erythropolis strain was the most active among pure cultures. Various stages of bacterial interaction with oil drops were followed by means of fluorescent microscopy.

Microflora in the basal strata at Antarctic ice core above the Vostok lake.

The microbiological investigations of the Antarctic ice core at the Vostok station become especially important in connection with the discovery of an subglacial lake in this region. This lake is considered by the world-wide scientific community to be an important object for searching for relict forms of life on the Earth and also as a model for solving a number of problems of exobiology--for instance for development of methods to penetrate into underice sea at Europe--Jupiter's satellite. For the first time the Antarctic ice core samples were taken from the horizons which correspond to the basal zone (3534-3541 m) and to the accreation ice zone (3555-3611 m) above the subglacial lake Vostok. As a result of the microbiological investigations it was shown that the total number of microbial cells have been in the same range of quantities as at the upper, younger horizons and varied from 1.3 x 10(2) up to 9.6 x 10(2) cl/ml. Some periodicity in the cell concentration and in their morphological diversity was revealed along the core. The maximal number and the greatest morphological variety were detected at horizons with the depth of 3534, 3555 and 3595 m. A drop in the cell concentration two or three times as much was found in ice layers under each of the above mentioned horizons. The discovered stratification is apparently connected with the periodicity of the lake water interactions with the basal ice layer and obviously depends on the complex natural events which took place in the geological history of our planet.

[Effect of the media salinity on destruction of petroleum oils by nocardioform bacteria]. / Vliianie solenosti sredy na destruktsiiu neftianykh masel nokardiopodobnymi bakteriiami.

Oil degradation by cultures of Rhodococcus erythropolis and Dietzia maris was found to depend on the NaCl concentration in the medium. Optimal utilization of turbine oil by R. erythropolis and D. maris was observed at 0.5 and 2 to 5% NaCl concentration, respectively. Mineral oil and a mixture of paraffins (C14-C18) were utilized within a broader range of the medium salinity. As shown by fluorescent microscopy, D. maris colonies formed on the oil drop surface, whereas R. erythropolis cells penetrated the drops. The strains studied may populate various ecological niches in oil-containing ecosystems. They are promising for the development of microbial preparations for cleaning the environment from oil pollution.

[Microbiological characterization of the accreted ice of subglacial Lake Vostok, Antarctica]. / Mikrobiologicheskaia kharakteristika akkretsionnogo l'da nad ozerom Vostok (Antarktida).

The accreted ice of subglacial Lake Vostok extends upward from the lake water level (a depth of 3750 m) to the bottom surface of the overlying Antarctic ice sheet. All of the accreted ice samples, taken from depths between 3541 and 3611 m, were found to contain pro- and eukaryotic microorganisms, whose number and diversity varied in different ice horizons and correlated, to a certain degree, with the occurrence of organic and inorganic impurities in a given horizon. Some biological objects found in the accreted lake ice, including bacteria, microalgae, and the pollen of higher plants, were morphologically similar to those found earlier in the glacier ice bulk. The others were not. It is suggested that the microorganisms found in the lake ice may come from different locations--the bottom layer of the glacier ice, the bedrock underlying the glacier, and the lake water.

[Determining the concentration of eukaryotic cells by their integral fluorescence]. / Opredelenie kontsentratsii éukariotinykh kletok po ikh integral'noi fluorestsentsii.

A proportional relationship was established between the total luminescence intensity of eukaryotic cells trapped on membrane filters and stained with fluorescent dyes and the number of cells present on the specimen area corresponding to the size of the cytofluorometric unit probe. An integral fluorescent method was developed that allows determination of the concentration of somatic cells in milk samples with the help of a calibration curve constructed on the basis of counting yeast cells. The method allows determination of the cell concentration in a 1 x 10(5)-5 x 10(6) cells/ml range. The results obtained using the integral fluorescent method are compared with data of direct visual count and with readings of the automatic FOSSOMATIK device.

[A fluorescent-cytochemical method for selective detection of yeast mitochondrial DNA]. / Fluorestsentno-tsitokhimicheskii metod izbiratel'nogo vyiavleniia mitokhondrial'noi DNK drozhzhei.

Yeast mitochondrial DNA (mDNA) can selectively be detected using a specific dye (DAPI). Nuclear DNA (nDNA) was stained along with mDNA only in three out of the fifteen studied yeast strains. Visualisation with a luminescent microscope showed that mDNA content varied among different yeast species as well as the size and shape of fluorescent mitochondrial nuclei. Intensive nDNA fluorescence was detected when a fixed specimen was treated with DAPI. Under these conditions, mDNA was revealed only in yeast cells with its high content. The process of fixation was shown to interfere with the integrity of mitochondria. It is also possible that the structure of DNA was modified to affect its interaction with the dye and thus the level of fluorescence. The developed technique of selective mDNA staining and the experimental results make it possible to gain a more accurate quantitative information about DNA content at the cellular level using cyto- and spectrofluorimetric techniques. This study involves important aspects pertinent to the dye interaction with yeast nuclear and mitochondrial DNA, both native and subjected to different fixation procedures.

[Change in the structural organization of Mycobacterium rubrum cells upon the action of ethidium bromide]. / Izmenenie strukturnoi organizatsii kletok Mycobacterium rubrum pri deistvii étidiuma bromida.

The action of ethidium bromide on Mycobacterium rubrum cells was studied. The culture growth was found to depend on ethidium bromide (EB) concentration in the medium. The reaction of EB with nucleoid DNA was shown to be specific and changes in the nucleoid structure were detected. Low EB doses (ca. 2 micrograms/ml) caused DNA despiralization in many cells. The process was reversible, which accounted for the elevated ability of reactivation at low EB doses. A higher EB dose (ca. 5-10 micrograms/ml and more) made the nucleoid structure coarser and denser in most cells and the nucleoid broke down to small fragments. As a result, due to the pool of enzymes present in the cells prior to EB addition, secondary changes developed. They involved all the cellular structures as well as the metabolism of lipids, polyphosphates, and glycogen. As a rule, these changes were incompatible with the cell viability.

[Light optical and electron microscopic study of the microflora of the parchment of an ancient Greek manuscript]. / Svetoopticheskie i élektronno-mikroskopicheskie issledovaniia mikroflory pergamenta drevnegrecheskoi rukopisi.

The microflora of an ancient Greek manuscript parchment was studied using different microscopic techniques. The manuscript was found to be infected with a large number of both Gram-positive and Gram-negative bacteria and with occasional micromycetes. The localisation of cells in the parchment was established, and the information was obtained pertinent to the functional state and the ultrastructural organisation of bacteria, as well as to the character of their interaction with the structural elements of the parchment.

[Structural and ultrastructural changes in Mycobacterium rubrum cells exposed to penicillin]. / Strukturnye i ul'trastrukturnye izmeneniia kletok Mycobacterium rubrum pri vozdeistvii na nikh penitsillinom.

The action of penicillin taken at subbacterioscopic doses on Mycobacterium rubrum cells causes changes in the size and shape of the cells, in the structure of the cell wall, in the intracellular membrane systems and in functions associated with them, and in the structure of nucleoids whose DNA packing becomes more loose. If the antibiotic is added at bacteriostatic doses, the size and shape of the cells do not change, but peptidoglycan precursors being synthesized are not incorporated into the polymer and accumulate in the periplasm. DNA overspiralization in nucleoids is a non-specific reaction, which indicates that DNA is physiologically passive. DNA is isolated with a membrane from the cytoplasm in certain cells. It is possible that the resistance of cells against penicillin is associated with the capability of DNA to become inactive in physiological terms.

[Ultrastructural and biochemical changes in Mycobacterium rubrum and Streptomyces bacillaris cells exposed to the herbicide semeron]. / Ul'trastrukturnye i biokhimicheskie izmeneniia v kletkakh Mycobacterium rubrum i Streptomyces bacillaris pri deistvii gerbitsida semerona.

The work was aimed at studying how the herbicide semerone affected the ultrastructure of two soil microorganisms, Mycobacterium rubrum and Streptomyces bacillaris. Depending on its concentration, the herbicide inhibited growth processes so that biomass yield decreased, cell division was interfered with, and giant and misshapen cells appeared. The herbicide taken at a concentration of 50-100 mg/ml increased the amount of membrane structures of the respiration type in some cells. This compound at a concentration of 400-500 mg/ml changed the nucleoid structure in certain cells. The decrease number of ribosomes and their peculiar distribution in the cell cytoplasm are most typical responses of the cells to the herbicide action. These responses were found in all cells at any of the tested herbicide concentrations. The results of cytological experiments are supported by statistically reliable data on the effect of the herbicide on RNA and protein synthesis. RNA synthesis is inhibited at a semerone concentration as low as 1 mg/ml, which is a very sensitive indicator of its presence in the medium.

[Ultrastructural changes in Mycobacterium rubrum cells exposed to sulfochloranthine]. / Ul'trastrukturnye izmeneniia v kletkakh Mycobacterium rubrum pri vozdeistvii sul'fokhlorantina.

The object of this work was to study the effect of sulfochlorantine (SCA), a new disinfecting compound containing chlorine, on Mycobacterium rubrum cells. The sensitivity of the cells to this agent was studied as well as their ultrastructure at the doses 0.01, 0.025, 0.05 and 0.1%. Even at high doses, the cells did not die off immediately when their growth and division stopped. Changes in the ultrastructural organization of the cells depended on the concentration of SCA. The structure of the nucleoid, membranes and ribosomes was damaged. Considerable changes were found in the formation of cross septa. The structure of the cells wall was modified to a lesser degree. The results are consistent with the biochemical data available.

[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.

[Relationship between the number of nucleoidosomes and the stage of development of Mycobacterium rubrum cultures]. / Izmenenie kolichestva nukleoidosom v zavisimosti ot stadii razvitiia kul'tury Mycobacterium rubrum.

This work has confirmed that the nucleoidosome (mesosome) of Gram-positive bacteria is a specialized invagination of the cytoplasmic membrane and serves for accommodating the replicative centres of nucleoid homologous chromosomes. The structure is not constant, it arises under specified conditions of cultivation and at certain growth stages which are characterized by decelerated division of nucleoids and cells while the rate of DNA replication does not change.

[Biological significance of nucleosomes in bacteria]. / O biologicheskom znakleoidosom u bakterii.

The paper presents data concerning the structural organization of specialized membrane structures in bacterial cells, viz. nucleoidosomes involved in DNA replication. A possible correlation between the number of homologous chromosomes in a nucleoid, the presence of nucleodosomes and their dimensions is discussed. Apparently, the role of nucleoidosomes is to increase the active surface of a plasmalemma region necessary to locate the replicative centers of circular DNA molecules in bacterial nucleoids.

[Structure and physico-chemical properties of bacterial flagella]. / Struktura i fiziko-khimicheskie svoistva bakterial'nykh zhgutikov.

The structural organization of bacterial flagella was studied with Bacillus brevis and Escherichia coli MS 1350. The presence of a spherical body at the basis of a flagellum was confirmed. The structural organization of ingredients of the flagellar appratus, its inner and outer part, was investigated. The molecular weight of protein subunits in the filamentous portion of the flagellum was assayed as well as their amino acid composition. The mode of attachment of the flagellum to the cell is discussed.