Biomedical subjects
Publications and source records attributed to E I Kvasnikov.
The composition of free mycolic acids was studied in the cells of Brevibacterium ammoniagenes ATCC 6871, B. flavum 22, B. stationis ATCC 14403, Corynebacterium divaricatum ATCC 14020 and Rhodococcus maris IMV 195. The acids are a mixture of saturated and unsaturated compounds with the total number of carbon atoms from 32 to 36 and the number of C atoms in the alpha-chain from 10 to 15.
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Waters of the Truskavetz deposit with a low content of mineral substances were found to contain considerable amounts of microorganisms; upto millions of cells per 1 ml. Sulphate-reducing, dentrifying and iron bacteria were detected in the waters. The following genera were represented and isolated: Pseudomonas, Bacillus, Nocardia, Arthrobacter, Brevibacterium, Corynebacterium, Micrococcus, Candida, Cryptococcus, Rhodotorula, Hansenula, Torulopsis, Trichosporon. Many of the studied strains assimilated C6--C10 and C12--C22 mixtures, industrial paraffins, naphthenic acids and their salts. The isolated bacterial and yeast strains were much more carbooligotrophic as compared to the museum strains of the same species; many of them were oligotrophic. The cells continued to grow in the course of storage of isolated water samples. The majority of isolated pure cultures grew upon inoculation into sterilized mineral water and caused a decrease in the content of organic substances.
The growth cycles and the types of cell separation were studied in a microchamber with the collection strains of Brevibacterium ammoniagenes ATTC 6871, B. helvolum ATCC 19239, B. linens CCM 47 and ATCC 9174, B. maris VKM B-464 and B. stationis ATCC 14403, as well as with the strains of the genus Rhodococcus isolated from soils, viz. R. maris sp. nov. IMB 283 and R. luteus sp. nov. IMB 385. According to the increasing complexity of cellular morphological transformation in the life cycle, the organisms may be arranged in a series: R. maris -- B. ammoniagenes -- B. stationis -- B. linens -- B. helvolum -- R. luteus. The first three organisms are characterized by the snapping type of separation of short rod-like daughter cells. The cells of B. linens separate by both the snapping and bending types. The coccoid cells of B. helvolum ATCC 19239 produce many buds which are transformed into rod-like cells in the course of growth. In the log phase of growth, both true and false branching of the cells is observed; the latter is the result of a peculiar growth of the ends in the separated cells of B. helvolum. The cells of R. luteus form a rudimentary, rapidly fragmenting mycelium whose rod-like elements divide then by binary fission; the daughter cells separate the bending and snapping types.
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Nocardioform bacteria characterized by the IV type of the cell wall and by lipid LCN-A are widely distributed in various soils of the Ukrainian SSR. The acetamidase-negative forms of Nocardia asteroides were found in 24.4% of soil samples, and the acetamidase-positive forms of this organism, in 4% of soil samples. The "rhodochrous" group was most often represented by the species N. erythropolis and N. rubropertincta, and less often, by Nocardia (Rhodococcus) rhodochrous, N. opaca and N. flava. The greatest amount of different species was detected in chernozem and dark chestnut soils of the waste zone. Chernozem soils impregnated with petroleum were particularly abundant in N. asteroides, N. rubropertincta, N. corallina and N. erythropolis. The best medium for isolation of most species was the Münz medium containing n-alkanes.
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The content of heavy metals in the water bodies increases as a result of anthropogenic effects. Heavy metals exert toxical effect on hydrobionts. Involved into the trophic chain they can be the cause of grave human diseases. Microorganisms possess a capacity to accumulate heavy metals in their body, evoke the process of their enzymatic transformation into nontoxical compounds and adsorb them on the cell surface. When breeding bacterial strains for the biological treatment of sewage from the metal-working plants the authors recommend to choose the cultures from econiches containing heavy metal compounds and to establish their resistance to high concentrations of metals. This resistance correlates with high biological activity. The bacterial strains of Pseudomonas genus possessing a capacity to sulphate reduction have been selected. As a result of their activity the high-solvable toxical sulphates are restored to practically unsolvable precipitating forms. A new species Aeromonas dechromatica transforming high-toxical six-valence chromium into low-toxical three-valent ones is described. The grounds of biotechnologies of the use of the breeded cultures for treatment of industrial sewage are stated.
The ability to assimilate n-alkanes form hexane to decane was studied among 495 collection strains and 27 freshly isolated strains belonging to the genus Pseudomonas. All freshly isolated strains and over one third of collection cultures of Ps. aurantiaca grow on mineral media with n-alkanes of low molecular weight, but do not assimilate heavy paraffins. The strains of Ps. aeruginosa, Ps. fluorescens and Ps. putida, isolated from oilbearing soils, and individual collection cultures, belonging to the two latter species, can assimilate both n-alkanes of low molecular weight (C6--C10) and heavy paraffins. Contrary to Ps. aurantiaca, other species of the Pseudomonas genus lose the ability to assimilate n-alkanes of low molecular weight after cultivation on rich organic media. An increase in the concentration of the mixture of low molecular weight paraffins (to 20 per cent by volume) has no toxic effect on the Pseudomonas bacteria whose biomass has a high content of protein and all necessary amino acids. The strains of Ps. aurantiaca produce a highly active antibiotic preparation consisting of floroglucine derivatives on the defined medium with n-alkanes of low molecular weight. The ratio between components of the preparation obtained on the media with n-alkanes and on the optimal organic media is different.