Publications by authors named "Velikov V"

While the authors have previously developed a method of pistil filament treatment with Agrobacterium cells during blossoming for the transformation of maize generative cells, the mechanism for bacterial T-DNA penetration into the embryo sac remained unknown. This article analyzes the possibility of agrobacterial penetration into the maize embryo via pollen tubes. Microbiological, PCR, and GUS techniques were used to confirm that agrobacteria could spread for up to 20 cm from the sie of inoculation and were detected in maize embryo tissues as aerly as 24 h after inoculation, while they were not revealed after 5-13 days.

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The bacteriophage ΦAb-Sp7 was isolated from the cells of the Azospirillum brasilense Sp7. The morphology, size of the gram-negative colonies, and range of lytic activity against other strains and species of the genus Azospirillum was tested. The isolated phage DNA was examined using electrophoretic and restriction analysis, and the size of the genome were established.

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Abstract-A transfer DNA (T-DNA) carrying the marker gene nptII was detected in the genomes of diploid and haploid maize plants obtained after the treatment of pistil filaments with a suspension of Agrobacterium during artificial pollination. PCR analysis of total DNA isolated from 155 canamycin-resistant diploid F1 seedlings revealed T-DNA insertions in the genomes of 111 plants (32.7% of the total number of analyzed seeds).

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The nucleotide sequences of mitochondrial genome fragments containing the genes coding for cytochrome oxidase subunit III (COIII) and 12S ribosomal RNA of common European viper and Nikolsky's viper from various habitats (Saratov, Samara, and Penza oblasts; Chuvash Republic; and the Republic of Mordovia) were determined. According to the sequencing data, all samples clustered into two groups except for a number of individuals carrying single mutations in the genes in question. One group comprised V.

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Integration of T-DNA into the maize genome as a result of treatment of silks with Agrobacterium cells, containing activated vir genes, was demonstrated. In planta treatment of maize (Zea mays L) was performed during flowering in field. Cell suspension of Agrobacterium tumefaiciens strain GV3101(pTd33), carrying activated vir genes, was applied onto the previously isolated silks, which were afterwards pollinated with the pollen of the same cultivar.

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The scFv miniantibodies to the recombinant protein VirE2 from Agrobacterium tumefaciens were obtained by the method of phage display. The miniantibodies were purified and tested using timmunodot method for binding to a recombinant protein from Escherichia coli and to the native protein VirE2 from A. tumefaciens.

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Bacteria of the genus Agrobacterium are capable of transferring a fragment of their Ti-plasmid, T-DNA, in a complex with the proteins VirE2 and VirD2, into the nuclei of plant cells and incorporating it into the chromosome of the host. The mechanisms of T-DNA transportation through membrane and cytoplasm of the plant cell are unknown. The aim of this work was isolation of virulence protein VirE2 for studying its role in T-DNA transportation through the membrane and cytoplasm of eukaryotic cells.

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Bacteria of the genus Agrobacterium can transfer a portion of their Ti plasmid (T-DNA) in complex with the VirE2 and VirD2 proteins into the plant-cell nucleus and cause it to be integrated in the host-cell chromosomes. The mechanism of T-DNA transfer across the plant-cell membrane and cytoplasm is unknown. The aim of this study was to isolate the virulence protein VirE2 in order to explore its role in T-DNA transfer across the eukaryotic-cell membrane and cytoplasm.

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Exocellular structures containing VirB2 proteins were, for the first time, localized on the surface of Agrobacterium by transmission electron microscopy. Using colloidal gold (CG)-labeled VirB2-specific antibodies, it was shown that VirB2 proteins enter into the composition of short surface pili, which emerge at the poles of acetosyringone (AS)-inducedAgrobacterium cells. However, cells of the Ti plasmidless A.

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The glass transition temperature (Tg) in water is still uncertain, with conflicting values reported in the literature. As with other hyperquenched glasses, water exhibits a large relaxation exotherm on reheating at the normal rate of 10 kelvin (K) per minute. This release of heat indicates the transformation of a high enthalpy state to a lower one found in slow-cooled glasses.

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Skin thigh biopsies were regularly taken in 186 patients with insulin-dependent and non-insulin-dependent diabetes. Progression of diabetic microangiopathy was found in spite of hypoglycemic treatment. Development of lesions of microvessels was somewhat inhibited only by angioprotectors (ticlid, dyamicron, dipiridamol).

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Femoral skin biopsies of 300 patients with insulin-dependent and non-insulin-dependent diabetes were studied immunomorphologically and the results were compared to the level of immunoglobulins in the blood serum. It is found that IgG, beta-lipoproteins, complement were registered in the arterioles and capillary walls in diabetic microangiopathy more frequently than in healthy persons. The conclusion is made that in development of diabetic microangiopathy, in both types of diabetes, immune (immunocomplex) mechanisms that damage vascular wall are involved.

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The process of the transfer of the Ti-plasmid vector pGV3850 with the plasmid pBR322 inserted into the T-DNA region from Agrobacterium tumefaciens to a non-plasmid strain of Escherichia coli was studied. The transferred Ti-plasmid was found to be exposed to deletions and formed a wide range of derivatives with a size ranging from 3-4 kb to 50 kb, maintained in E. coli due to ColE1-replicon.

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As shown by conjunctival biomicroscopy, 6-month administration of ticlid and gliclazide induced a statistically significant increase in the frequency of less severe microcirculatory disturbances compared to conventional hypoglycemic therapy. The drugs also restricted plasmatic impregnation and cell proliferation in skin biopsy microvascular wall. Following 2-year antiaggregation treatment (gliclazide, trental, dipiridomol) 48.

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Hemocoagulation was examined in 477 diabetes mellitus patients. Whatever the disease type, severity, duration and the intensity of microvascular complications, diabetes mellitus was discovered to be marked by the development of chronic intravascular blood microcoagulation associated with primary hyperactivation of the platelet component of hemostasis. The use of the new antiaggregation agents tiklid and diabeton allows an appreciable decrease of the activity of platelet microthrombus formation whereas the administration of the common sugar-reducing antidiabetic therapy favours the maintenance of its high level.

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Skin biopsies from 40 patients 17 to 75 years old with type I and II diabetes mellitus were studied morphologically. The formation of diabetic microangiopathy starts with the damage of endotheliocytes, vascular permeability disturbance, activation of pericytes and smooth muscle elements with subsequent thickening of basal membranes and capillary and arteriole hyalinosis, these lesions being directly related to the duration of diabetes. Diabetic microangiopathy is a manifestation of the disease and its morphology is similar in both type I and II diabetes.

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A study was made of the immunological mechanisms implicated in the evolution of diabetic microangiopathy. For this purpose in 270 patients with type I and II diabetes mellitus, the concentration of IgA, IgM and IgG was measured and compared with morphological alterations in skin biopsy specimens. The control group was made up of 30 normal persons (donors).

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