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61.
62.
M S Konstantinova O A Danilova 《Biulleten' eksperimental'no? biologii i meditsiny》1975,80(9):100-102
Distribution of adrenergic and peptidergic nerve fibers in rat median eminence was studied three weeks after bilateral adrenalectomy. Fluorescence intensity in the external zone and in some of the nerve cell-bodies proved to be increased in the nucleus arcuatus. There were many nerve fibers with a bright fluorescence in the internal zone. A great number of the peptidergic nerve fibers appeared in the external zone. Reactions in the rostral, medial and caudal regions of the median eminence differed and were described. 相似文献
63.
64.
N D Konstantinova L N Kats G A Kotliarova I I Fedotova 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1975,(2):58-61
A study was made of ultrathin sections of the stable l-forms of listeria obtained under the action of penicillin in meat-peptone-liver broth. A marked cellular polymorphism was found in the L-form culture: within the same colony cells differed in size, shape and fine structure. It is supposed that polymorphism could be partially explained by a different plasticity and premeability of cytoplasmic membrane in different types of cells of the same L-colony. The three-layer structure of the membrane does not always display the same distinctness in various L-colony cells and also in different areas of the cell surface. Structureless material of low electron density, possibly a defective murein or its precursor, was revealed on the membrane surface. Electrondense inclusion bodies, mesosomes of ring-shaped or more complicated structure and two-contour vesicles were found in the cytoplasm. The cells multiplied by budding, by binary and anomalies division participation of mesosomes in this process was not proved by the L-forms. 相似文献
65.
Ying Poi Liu Jens Gruber Joost Haasnoot Pavlina Konstantinova Ben Berkhout 《Nucleic acids research》2009,37(18):6194-6204
Potent antiviral RNAi can be induced by intracellular expression of short hairpin RNAs (shRNAs) and artificial microRNAs (miRNAs). Expression of shRNA and miRNA results in target mRNA degradation (perfect base pairing) or translational repression (partial base pairing). Although efficient inhibition can be obtained, error-prone viruses such as human immunodeficiency virus type 1 (HIV-1) can escape from RNAi-mediated inhibition by mutating the target sequence. Recently, artificial miRNAs have been shown to be potent RNAi inducers due to their efficient processing by the RNAi machinery. Furthermore, miRNAs may be more proficient in suppressing imperfect targets than shRNAs. In this study, we tested the knockdown efficiency of miRNAs and shRNAs against wild-type and RNAi-escape HIV-1 variants with one or two mutations in the target sequence. ShRNAs and miRNAs can significantly inhibit the production of HIV-1 variants with mutated target sequences in the open reading frame. More pronounced mutation-tolerance was measured for targets in the 3′ untranslated region (3′ UTR). Partially complementary sequences within the 3′ UTR of the HIV-1 RNA genome efficiently act as target sites for miRNAs and shRNAs. These data suggest that targeting imperfect target sites by antiviral miRNAs or shRNAs provides an alternative RNAi approach for inhibition of pathogenic viruses. 相似文献
66.
M. A. Rosenfeld V. B. Leonova M. L. Konstantinova S. D. Razumovskii 《Biochemistry. Biokhimii?a》2009,74(1):41-46
The mechanism of self-assembly of fibrin monomers and fibrinogen aggregation during ozone oxidation has been studied by the methods of elastic and dynamic light-scattering and viscosimetry. Fibrin obtained from oxidized fibrinogen exhibits higher average fiber mass/length ratio compared with native fibrin. Fibrinogen ozonation sharply reduced the latent period preceding aggregation of protein molecules; however, the mechanism of self-assembly of ozonated and non-ozonated fibrinogen cluster was identical. In both cases flexible polymers are formed and reaching a certain critical length they form densely packed structures and aggregate. Using infrared spectroscopy, it has been shown that free radical oxidation of amino acid residues of fibrinogen polypeptide chains catalyzed by ozone results in formation of carbonyl, hydroxyl, and ether groups. It is concluded that fibrinogen peripheral D-domains are the most sensitive to ozonation, which causes local conformational changes in them. On one hand, these changes inhibit the reaction of longitudinal polymerization of monomeric fibrin molecules; on the other hand, they expose reaction centers responsible for self-assembly of fibrinogen clusters. 相似文献
67.
Rosenfeld MA Leonova VB Shchegolikhin AN Razumovskii SD Konstantinova ML Bychkova AV Kovarskii AL 《Biochemistry. Biokhimii?a》2010,75(10):1285-1293
Ozone-induced free-radical oxidation of fragments D and E from fibrinogen has been studied. The methods of elastic and dynamic light scattering in combination with electrophoresis
of unreduced samples have shown the acceleration of enzymatic covalent crosslinking of molecules of oxidation-modified fragment
D under the action of factor XIIIa. UV and IR spectroscopy shows that free-radical oxidation of amino acid residues of polypeptide
chains catalyzed by ozone affects the cyclic and amino groups, giving rise to generation of mainly oxygen-containing products.
Comparison of the IR spectra obtained for the oxidation-modified D and E fragments revealed more significant transformation of functional groups for the D fragment. EPR spectroscopy showed that the rotational correlation time of spin labels bound to the ozonized proteins decreased
in comparison with the non-ozonized proteins. The rotation correlation time of the radicals covalently bound to the ozonized
D and E fragments suggests that D fragment of fibrinogen is more sensitive to free-radical oxidation followed by local structural changes. Possible causes
of different degrees of oxidation for fragments D and E are discussed. 相似文献
68.
Serkina AV Zalunin IA Levitin EI Voejkova TA Tyaglov BV Novikova LM Emeljanova LK Konstantinova GE Chestukhina GG 《Biochemistry. Biokhimii?a》2010,75(8):1032-1038
A metallocarboxypeptidase produced by Streptomyces bikiniensis 27 strain (VKPM Ac-1783) (CPSb) was purified and characterized. The enzyme cleaves both basic and hydrophobic C-terminal
amino acid residues from synthetic peptides, that is, it possesses specificity of mammalian carboxypeptidases A and B. The
enzyme also hydrolyzes peptides bearing glutamic acid at the C-end. CPSb exhibits its maximal activity at pH 7.0–7.6 and 55°C.
The nucleotide sequence encoding the mature CPSb in S. bikiniensis 27 (VKPM Ac-1783) genome (Accession No. GU362077) was determined. It is shown that the primary structure of the mature enzyme
has a moderate degree of identity with orthologs from Streptomyces griseus (79% identity) and Streptomyces avermitilis (85% identity). 相似文献
69.
G. R. Kalamkarov T. S. Konstantinova A. E. Bugrova T. F. Shevchenko I. V. Tsapenko M. V. Zueva A. N. Ivanov 《Biophysics》2010,55(4):610-614
The possibility and the mechanism of the reduction of nitrites in retinal vessels under acute hypoxia in vivo have been investigated.
An experimental model of rat retinal ischemia was elaborated using laser coagulation of retinal vessels. It was demonstrated
that vessel thrombosis does not occur if the nitrite concentration in the vessels is increased. It was proposed that, under
acute hypoxia, nitrites are reduced to NO, which results in drastic vasodilatation. Considering that the effect takes less
than a minute, this reduction cannot be due to hypoxic acidosis but is more likely associated with NO reduction by heme proteins.
It was found that increased concentration of nitrites protects the retina from the development of ischemia progress and that
preliminary administration of nitrites prevents apoptosis in the retina and a decrease in its photoelectric activity. 相似文献
70.
V. A. Khripach V. N. Zhabinskii O. V. Gulyakevich O. V. Konstantinova A. Yu. Misharin A. R. Mekhtiev V. P. Timofeev Ya. V. Tkachev 《Russian Journal of Bioorganic Chemistry》2010,36(6):746-754
The convergent synthesis of biosynthetic precursors of brassinosteroids with a Δ2-bond in cycle A—secasterol and 24-episecasterol—was performed. The key stages in the construction of the side chain in these
compounds were the Julia olefination of the steroid 22-aldehyde followed by the Sharpless asymmetric dihydroxylation of the
intermediate Δ22-olefin. The cytotoxicity of the synthesized compounds for breast carcinoma MCF-7 cells was assessed. 相似文献