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41.
Two spirochete strains isolated earlier from "Thiodendron" bacterial sulfur mats grew better under microaerobic (0.3-0.5 mg O2/l) than under anaerobic conditions. The microaerobic growth of these strains was accompanied by a twofold increase in the cell yield and the efficiency of glucose utilization, despite an amount of ATP (and hence glucose) was spent in this case for the synthesis of exopolysaccharides. Glucose metabolism under microaerobic conditions gave rise to more oxidized products (acetate and carbon dioxide) than under anaerobic conditions (formate, ethanol, pyruvate, and hydrogen). The paper considers two putative mechanisms implemented by aerotolerant spirochetes: adaptive (the use of a more efficient pathway of glucose catabolism) and protective (an enhanced synthesis of exopolysaccharides and the reduction of hydrogen peroxide by the reduced sulfur compounds thiosulfate and sulfide, yielding elemental sulfur). The formation of "Thiodendron" bacterial sulfur mats in saltwater environments is also discussed. 相似文献
42.
The mutation rates of di-, tri- and tetranucleotide repeats in Drosophila melanogaster 总被引:3,自引:1,他引:3
Schug MD; Hutter CM; Wetterstrand KA; Gaudette MS; Mackay TF; Aquadro CF 《Molecular biology and evolution》1998,15(12):1751-1760
In a recent study, we reported that the combined average mutation rate of
10 di-, 6 tri-, and 8 tetranucleotide repeats in Drosophila melanogaster
was 6.3 x 10(-6) mutations per locus per generation, a rate substantially
below that of microsatellite repeat units in mammals studied to date (range
= 10(-2)-10(-5) per locus per generation). To obtain a more precise
estimate of mutation rate for dinucleotide repeat motifs alone, we assayed
39 new dinucleotide repeat microsatellite loci in the mutation accumulation
lines from our earlier study. Our estimate of mutation rate for a total of
49 dinucleotide repeats is 9.3 x 10(-6) per locus per generation, only
slightly higher than the estimate from our earlier study. We also estimated
the relative difference in microsatellite mutation rate among di-, tri-,
and tetranucleotide repeats in the genome of D. melanogaster using a method
based on population variation, and we found that tri- and tetranucleotide
repeats mutate at rates 6.4 and 8.4 times slower than that of dinucleotide
repeats, respectively. The slower mutation rates of tri- and
tetranucleotide repeats appear to be associated with a relatively short
repeat unit length of these repeat motifs in the genome of D. melanogaster.
A positive correlation between repeat unit length and allelic variation
suggests that mutation rate increases as the repeat unit lengths of
microsatellites increase.
相似文献
43.
Natalia N. Pozdnyakova Svetlana V. Nikiforova Oleg E. Makarov Marina P. Chernyshova Kirill E. Pankin Olga V. Turkovskaya 《World journal of microbiology & biotechnology》2010,26(2):205-211
For the first time the dependence of completeness of pyrene degradation by the white-rot fungus Pleurotus ostreatus D1 on cultivation conditions was found. In Kirk’s medium about 65.6 ± 0.9% of the initial pyrene was metabolized after 3 weeks, with pyrene-4,5-dihydrodiol accumulating. This process was accompanied by laccase production only. In basidiomycetes rich medium, P. ostreatus D1 metabolized up to 89.8 ± 2.3% of pyrene within 3 weeks without pyrene-4,5-dihydrodiol accumulation throughout the time of cultivation. Phenanthrene and phthalic acid were identified as the metabolites produced from pyrene degradation under these conditions. Accumulation of phenanthrene with its subsequent disappearance was observed. One more metabolite probably was the product of phenanthrene degradation. Pyrene metabolism in basidiomycetes rich medium was accompanied first by laccase and tyrosinase production and later by versatile peroxidase production. The cell-associated activities of laccase, tyrosinase, and versatile peroxidase were found. The data obtained indicate that both enzymes (laccase and versatile peroxidase) are necessary for complete degradation of pyrene. Furthermore, both cell-associated and extracellular laccases can catalyse the first stages of pyrene degradation, and versatile peroxidase can be necessary for oxidation of the resulting metabolites. 相似文献
44.
E. V. Dubrovskaya I. O. Polikarpova A. Yu. Muratova N. N. Pozdnyakova M. P. Chernyshova O. V. Turkovskaya 《Russian Journal of Plant Physiology》2014,61(4):529-536
Physiological, biochemical, and growth parameters of sorghum (Sorghum bicolor (L.) Moench) plants grown in the presence of phenantrene (10 and 100 mg/kg soil) were examined. Activities of intracellular tyrosinases, peroxidases, and laccase-like oxidases were analyzed in 1 and 2 months after planting. The tyrosinase activity in root and leaf tissues correlated positively throughout the experiment with the level of soil pollution. The oxidase activity was apparent only in the first month; it also correlated positively with the concentration of phenanthrene. Intracellular peroxidases exhibited the highest activity; positive correlation of this activity with the level of soil contamination was observed in the first period of observations. The soil pollutant had a negative impact on growth characteristics (germination capacity, survival rate, and accumulation of plant biomass). In addition, soil contamination with phenanthrene reduced the total content of photosynthetic pigments and changed their ratio. The maximum extent of phenanthrene elimination in soil was found to occur in the root zone of sorghum plants at high-level contamination, which indicates a significant contribution of plants to the decomposition (binding) of this xenobiotic. 相似文献
45.
S. V. Nikiforova N. N. Pozdnyakova O. E. Makarov M. P. Chernyshova O. V. Turkovskaya 《Microbiology》2010,79(4):456-460
The effect of cultivation conditions on chrysene bioconversion by the fungus Pleurotus ostreatus D1 was shown. Under the laccase production conditions, transformation of this polycyclic aromatic hydrocarbon occurs with
accumulation of the quinone metabolite. Under both the laccase and versatile peroxidase production conditions, chrysene degradation
occurs, with the stages leading to phthalic acid formation and its further utilization. The formation of phthalic acid as
a metabolite of chrysene degradation by white rot fungi was revealed for the first time. The data obtained suggest that the
laccase revealed on the mycelial surface and the extracellular laccase are probably involved at the initial stages of chrysene
metabolism, whereas versatile peroxidase seems to be required for oxidizing the metabolites formed. 相似文献
46.
Blaise?TF?Alako Antoine?Veldhoven Sjozef?van Baal Rob?Jelier Stefan?Verhoeven Ton?Rullmann Jan?Polman Guido?JensterEmail author 《BMC bioinformatics》2005,6(1):51
Background
High throughput microarray analyses result in many differentially expressed genes that are potentially responsible for the biological process of interest. In order to identify biological similarities between genes, publications from MEDLINE were identified in which pairs of gene names and combinations of gene name with specific keywords were co-mentioned. 相似文献47.
T F Chernyshova L I Pavlova N Ia Pokrovskaia G A Ershova T A Skirda 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1983,(5):81-84
The safety and reactogenicity of group A meningococcal polysaccharide vaccine prepared at the G. N. Gabrichevsky Research Institute for Epidemiology and Microbiology (Moscow) and intended for the immunization of children aged 5-14 years were studied. The data obtained in this study made it possible to characterize the preparation as safe and mildly reactogenic. Shifts in the blood formula registered 24 hours after the injection of the vaccine remained within the limits of physiological fluctuations. Subfebrile temperature persisting for 2 days was registered in some of the children aged 5-8 years. Local reaction in the form of hyperemia at the site of injection was insignificant. The optimum vaccination dose will be determined on the basis of the whole complex of the data presented in this work, as well as the data on the immunological activity of the preparation. 相似文献
48.
I. V. Kondakova L. V. Spirina E. E. Shashova V. D. Koval L. A. Kolomiets A. L. Chernyshova E. M. Slonimskaya 《Russian Journal of Bioorganic Chemistry》2012,38(1):89-92
Although proteasomes (multiproteinase protein complexes) are known to play an important role in cancer pathogenesis, there
is little information about their activity in human tumor tissues. The chymotrypsin-like activity of proteasomes in breast
cancer (BC) and endometrial cancer (EC) tissues was studied. It was shown that the chymotrypsin-like total proteasome activity
and the 20S and 26S proteasome pool activities were significantly higher in malignant than in normal tissues. An increase
in the size of either BC or EC tumors did not affect the proteasome activity, whereas the propagation of a malignant process
did. If compared with BC non-metastatic tumors, a reliable decrease in the total activity and the 26S proteasome activity
was observed in BC tumors with regional lymph node metastases. In EC tissues, the total proteasome activity and the 20S and
26S proteasome pool activities increased when the depth of tumor myometrial invasion grew. These data demonstrated that the
proteasome activity significantly varied in the process of carcinogenesis. Further proteasome studies could serve as the basis
for the development of new criteria for prognosis of female reproductive system cancer and the search for effective antitumor
agents in targeted therapy. 相似文献
49.
A P Alliluev O V Kotel'nikova T F Chernyshova T A Skirda V I Kuvakina 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1984,(3):106-112
The immunological effectiveness of dried group A meningococcal polysaccharide vaccine, developed at the Gabrichevsky Research Institute of Epidemiology and Microbiology, Moscow, for children aged 5-14 years was studied. The intensiveness of the immune response of children to 0.5 ml of the vaccine introduced in a single injection was evaluated by a rise in the level of agglutinating antibodies to group A meningococcal polysaccharide in the sera of the vaccinees 3-4 weeks after immunization with the following optimum doses: 25 micrograms for children aged 5-8 years, 50 micrograms for children aged 9-13 years and 75 micrograms for children aged 14 years and over. The vaccine was shown to be highly immunogenic. Antibodies to group A meningococcal polysaccharide were identified as IgM. These antibodies in a titer of 1:40 and higher could be detected in 90% of the vaccinated children in the younger age group, 7 months after immunization. 相似文献
50.