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71.
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
72.
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
73.
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
74.
Tatyana Avramova Dimitrina Spassova Sava Mutafov Svetlana Momchilova Lilyana Boyadjieva Boryana Damyanova Blaga Angelova 《World journal of microbiology & biotechnology》2010,26(6):1009-1014
Studied is the effect of the non-ionic surfactant Tween 80 on the microbial transformation of 4-androstene-3,17-dione into
its 9α-hydroxy-derivative by resting Rhodococcus sp. cells. The surfactant was applied in the cultivation medium as an additional source of carbon, in the transformation
reaction medium as a mediator of the steroid substrate solubility or was used for permeabilization of the glucose grown Rhodococcus sp. cells. Special attention is paid to the fact that Tween 80 accelerates the 9α-steroid hydroxylation reaction carried
out by glucose-grown cells. When the surfactant was applied as a supplementary source of carbon, the rate of the steroid hydroxylation
reaction was significantly lower. In addition, the kinetics of the transformation process changed into a linear one thus indicating
a very slow, if any, product degradation. The fatty acid profile, cell surface hydrophobicity as well as cell ultrastructure
observed by scanning and transmission electron microscopy in the Tween 80- and glucose-grown Rhodococcus sp. cells are compared and related with their 9α-hydroxylating activity. 相似文献
75.
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
76.
Konstantinova IM Kulichkova VA Evteeva IN Mittenberg AG Volkova IV Ermolaeva JB Gause LN 《FEBS letters》1999,462(3):407-410
For the first time small nuclear ribonucleoprotein particles (alpha-RNP) tightly bound to chromatin as well as cytoplasmic alpha-RNP are shown to possess strong and regulated endonuclease activity specific for mRNAs and hnRNAs. The enzymatic nature of this activity is confirmed, and the optimal conditions detected. This RNase activity is controlled by the action of a differentiating stimulus, dimethylsulfoxide, in human K562 cells. Small alpha-RNP involvement in the coordinated control of stability of pre-messenger RNA and messenger RNA molecules is suggested. 相似文献
77.
78.
Fragments of the nuclear and mitochondrial genes for the large-subunit rRNA were compared for Trichoplax sp. and T. adhaerens. High similarity was observed for their sequences, suggesting that different Trichoplax isolates belong to one species. 相似文献
79.
Didenko LV Konstantinova ND Solokhina LV Pushkareva VI Litvin VIu 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》2002,(1):17-23
The ultrastructural organization of Y. pseudotuberculosis in the process of the transition of vegetative cells into the dormant (noncultivable) state in interaction with blue-green algae of the species Anabaena variabilis was studied by the method of transmission electron microscopy. The use of type specific Y. pseudotuberculosis serum made it possible to identify Y. pseudotuberculosis cells in the bacterial association and to find out whether their antigenic properties remained intact in time. The dormant forms of Y. pseudotuberculosis, recultivated by passage through the axenic culture of unfusoria (Tetrahymena pyryformis), were also studied with the use of electron microscopy. The revertants were found to be at different stages of restoration of their typical morphological characteristics and antigenic properties were partially retained. The fine structure of Y. pseudotuberculosis cells in the initial culture was shown to be similar to that of the revertants of dormant forms, morphological criteria of the dormant cell ultrastructure were established. The cyclic processes of reversible transition from vegetative forms to dormant ones in bacterial populations under the influence of hydrobios is regarded as an adaptive mechanism of their existence in the environment. 相似文献
80.
Konstantinova ND Kormilitsyna MI Didenko LV Meshcheriakova IA 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》2000,(1):10-15
The electron-microscopic study of the interaction of F. tularensis virulent and attenuated strains with infusoria of the species T. pyriformis was dynamically studied. In this study the structural changes of F. tularensis and T. pyriformis cells, as well as their capacity for survival, were revealed. The data on their ultrastructure correlated with the dynamics of the number of both F. tularensis and T. pyriformis: during the whole term of observation the tendency to a slow decrease in the number of F. tularensis was registered with the concentration of T. pyriformis remaining stable. The interaction of F. tularensis with T. pyriformis may be regarded as a variant of commensal, but not antagonistic interactions. 相似文献