Phytochemical Analysis of Biotechnological Raw Materials of Representatives of the Genus Potentilla L.

Russian Journal of Bioorganic Chemistry - The genus Potentilla (Potentilla L.) is a member of the family Rosaceae, widespread in temperate, arctic, and alpine zones of the northern hemisphere. This...     

Genetic analysis of <Emphasis Type="Italic">Drosophila melanogaster</Emphasis> chromosome 3 neurodegenerative mutants induced with ethyl methanesulfonate

Neurodegeneration, a pathological state accompanied by brain neuronal necrosis and changes in behavior, has been described for many animal species. However, the genetic control and molecular mechanisms of this process are yet vague. A large collection of neurodegenerative mutants of a model object, Drosophila melanogaster, can enhance understanding of these mechanisms. In this work, we have demonstrated that genetically determined anatomical changes in Drosophila brain are accompanied by a decreased lifespan and deviations from the wild-type sexual behavior and locomotor activity. It has been found that the genes vacuous and loechrig are candidates for molecular genetic analysis in eight mutants from the collection.     

Telomerase: Structure,functions, and activity regulation

Telomerase is the enzyme responsible for maintenance of the length of telomeres by addition of guanine-rich repetitive sequences. Telomerase activity is exhibited in gametes and stem and tumor cells. In human somatic cells proliferation potential is strictly limited and senescence follows approximately 50–70 cell divisions. In most tumor cells, on the contrary, replication potential is unlimited. The key role in this process of the system of the telomere length maintenance with involvement of telomerase is still poorly studied. No doubt, DNA polymerase is not capable to completely copy DNA at the very ends of chromosomes; therefore, approximately 50 nucleotides are lost during each cell cycle, which results in gradual telomere length shortening. Critically short telomeres cause senescence, following crisis, and cell death. However, in tumor cells the system of telomere length maintenance is activated. Besides catalytic telomere elongation, independent telomerase functions can be also involved in cell cycle regulation. Inhibition of the telomerase catalytic function and resulting cessation of telomere length maintenance will help in restriction of tumor cell replication potential. On the other hand, formation of temporarily active enzyme via its intracellular activation or due to stimulation of expression of telomerase components will result in telomerase activation and telomere elongation that can be used for correction of degenerative changes. Data on telomerase structure and function are summarized in this review, and they are compared for evolutionarily remote organisms. Problems of telomerase activity measurement and modulation by enzyme inhibitors or activators are considered as well.     

Antiviral activity of aqueous extracts and polysaccharide fractions from mycelium and fruit bodies of higher fungi

Sixty preparations of basidiomycetes (Ganoderma, Lentinus, Pleurotus, Laetiporus, Polyporus, Inonotus, Flammulina, Grifola, Trametes) were investigated with respect to their toxicity for Vero cells and antiviral activity. The antiviral activity was estimated with the use of the West Nile virus and type 2 Herpes simplex. It was shown that 11 preparations of Ganoderma, Lentinus and Pleurotus completely inhibited the infective activity in doses not lower than 1000 TCD50 (the West Nile virus) and 100 PPU (type 2 Herpes simplex). The antiviral activity of the preparations was likely due to the content of polysaccharides or their derivatives in the composition. It increased with increasing of the quantity of the total polysaccharide fraction or its concentration.     

Effect of inhibitors of topoisomerases and poly(ADP-ribosylation) on homologous and non-homologous integration of exogenous DNA in genes of mammalian somatic cells

A study was made of the influence of inhibitors of poly(ADP-ribose)polymerase, topoisomerase I and topoisomerase II on the frequency of gene targeting of hprt gene as well as on the frequency of random integration of targeting vector pRV9.1 into genome of mouse F9 teratocarcinoma cells. We found that the treatment of cells with the inhibitor of poly(ADP-ribose)polymerase 3-aminobenzamide after electroporation resulted in 3-4-times increase of homologous integration of exogenic vector into chromosomal DNA, and did not affect the frequency of random insertion of transfected DNA. The treatment of cells after electroporation with inhibitors of topoisomerases VP-16, ICRF-193 enhanced random integration of transfected DNA but exerted no effect on the frequency of gene targeting in this experimental system.     

Analysis of the anaerobic microbial community capable of degrading p-toluene sulphonate

Three strains of Clostridium sp., 14 (VKM B-2201), 42 (VKM B-2202), and 21 (VKM B-2279), two methanogens, Methanobacterium formicicum MH (VKM B-2198) and Methanosarcina mazei MM (VKM B-2199), and one sulfate-reducing bacterium, Desulfovibrio sp. SR1 (VKM B-2200), were isolated in pure cultures from an anaerobic microbial community capable of degrading p-toluene sulfonate. Strain 14 was able to degrade p-toluene sulfonate in the presence of yeast extract and bactotryptone and, like strain 42, to utilize p-toluene sulfonate as the sole sulfur source with the production of toluene. p-Toluene sulfonate stimulated the growth of Ms. mazei MM on acetate. The sulfate-reducing strain Desulfovibrio sp. SR1 utilized p-toluene sulfonate as an electron acceptor. The putative scheme of p-toluene sulfonate degradation by the anaerobic microbial community is discussed.     

Unique error signature of the four-subunit yeast DNA polymerase epsilon

We have purified wild type and exonuclease-deficient four-subunit DNA polymerase epsilon (Pol epsilon) complex from Saccharomyces cerevisiae and analyzed the fidelity of DNA synthesis by the two enzymes. Wild type Pol epsilon synthesizes DNA accurately, generating single-base substitutions and deletions at average error rates of 5' exonuclease activity is less accurate to a degree suggesting that wild type Pol epsilon proofreads at least 92% of base substitution errors and at least 99% of frameshift errors made by the polymerase. Surprisingly the base substitution fidelity of exonuclease-deficient Pol epsilon is severalfold lower than that of proofreading-deficient forms of other replicative polymerases. Moreover the spectrum of errors shows a feature not seen with other A, B, C, or X family polymerases: a high proportion of transversions resulting from T.dTTP, T.dCTP, and C.dTTP mispairs. This unique error specificity and amino acid sequence alignments suggest that the structure of the polymerase active site of Pol epsilon differs from those of other B family members. We observed both similarities and differences between the spectrum of substitutions generated by proofreading-deficient Pol epsilon in vitro and substitutions occurring in vivo in a yeast strain defective in Pol epsilon proofreading and DNA mismatch repair. We discuss the implications of these findings for the role of Pol epsilon polymerase activity in DNA replication.     

Cell morphology, nucleus distribution and DNA content in haploid and diploid Aspergillus niger strains

The cells of haploid Aspergillus niger strains contain, on the average, 7-9 nuclei, a fragment of a thin hypha 100 me long comprising 11-19 nuclei. The cells of a diploid strain are 1.5-2.6 times larger in volume. The diploid cells contain less nuclei and more cytoplasm per nucleus as compared to the haploid strains. The primary sterigmae of Aspergillus niger comprise 3-13 nuclei, the secondary sterigmae and conidia, one nucleus. The conidia of the diploid strains are 1.8-2.0 times larger in volume and contain twice as much DNA as compared to the haploid strains.     

Morphofunctional changes in the lymph nodes and microcirculatory bed of small-intestinal mesentery of dogs in septic peritonitis after endolymphatic administration of ampicillin

With the aim to study effectiveness+ of endolymphatic (EL) administration of ampicillin (AC), using the model of an acute diffuse septic peritonitis in dogs, the morphological and morphometrical investigation has been performed concerning the state of the lymph nodes (LN), which are regional as regards the pathological focus (pelvic) and remote (tracheobronchial, mesenteric) and hemomicrocirculatory bed (HMCB) of the small intestine mesentery. All LN groups studied are involved in the pathological process, that produces certain increasing disturbances in the structure and cell composition in LN. In 6 h the changes are especially manifested in the pelvic LN, and in 18 h--in the animals without application of AC, or at its intramuscular injection LN lose their typical structure. Their dimensions and number of lymphoid nodules++ and medullary cords decrease, a sharp impoverishment of lymphocytes in LN is observed. By this time critical disturbances in the HMCB structure develop; they are characterized as presence of great amount of avascular areas in the mesentery, extended capillary loops, plasmatic saturation of interstitium. When AC is injected endolymphatically, simultaneously with peritonitis modelling T- and B-dependent zones in LN are preserved, a high volumetric part of lymphocytes is kept in all groups of LN, structure and function of HMCB are normalized. The pronounced delay in development and decreasing manifestation of infective-toxic disorder in LN and HMCB depend on effective concentrations of the antibiotic, produces in the lymphatic system.