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71.
Popov B 《Acta physiologica Hungarica》1999,86(1):69-75
Two parallel studies on albino male rats are performed. In the first study, there is a group which underwent resection of the proximal third of the small intestine. While the other group despite resection of the same segment also has a ligated common biliary and pancreatic duct. In the second study, one group of the experimental animals is only with ligated pancreatic duct and in the other group the same duct is implanted in the initial part of the ileum. On the 15th day after the surgical interventions the amylase activity and the absorption of glucose in the small intestine are studied by the method of turned sacs "in vitro". It is established that the glucose transport does not change after the four surgical interventions. However, the amylase activity increases about twice times after resection of the upper third of the small intestine and more than 4 times after resection of the same segment with simultaneous ligature of the common biliary and pancreas duct. Only at ligating the duct, the amylase activity is decreased in the jejunum and is significantly increased in the ileum, while its implantation in the initial part of the ileum does not change its activity in both studied segments of the small intestine. It is concluded that there are unknown inhibitors for the amylase activity in the biliary and pancreatic juice. The discussed issue is why they inhibit only the enzymatic compensatory processes without influencing the transport systems of the small intestine. 相似文献
72.
Popov VF Iunasova TN Gaĭderova LA Aksenov LA Averina OB Shitikova OIu 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》2004,(6):41-43
The work was aimed at the evaluation of the antigenic activity and reactogenicity of antirubella vaccine, manufactured by the Serum Institute of India, on the basis of the active observation of 373 children. Vaccinal reactions were registered in 8.8% of the vaccinees. Seroconversion after the injection of the vaccine was 100%. The results of the epidemiological trial demonstrated that the Indian antirubella vaccine was faintly reactogenic and had high antigenic activity. 相似文献
73.
The current methods of production of conditionally immortal cells in vivo and in vitro have been considered, including the method based on transgenesis of animals. Examples are given for utilization of conditionally immortal cells obtained in vivo from tissues of transgenic mice and rats carrying the gene of mutant T-antigen tsA58 SV40. The recent studies were analyzed, which concern the investigation and utilization of embryonic and regional stem cells, as well as immortal cells obtained through transfection of the recombinant construct of telomerase gene into human cells. The main problems of cell biotechnology are discussed. 相似文献
74.
Savostina EP Popov IuA Kashmanova TN Iashechkin IuI 《Molekuliarnaia genetika, mikrobiologiia i virusologiia》2004,(1):22-26
An analysis of genome polymorphism of the Y. pestis strains by using the method of polymerase chain reaction (PCR) for the tandem repeats of bacteriophage M13 DNA revealed a species similarity of both typical and atypical (according to diagnostic signs) plague-microbe strains. Strain Y. pestis A-1726 with the atypical differential-and-diagnostic properties, without the amplicon specified for Y. pestis and sized 1000 b.p., was identified among 27 analyzed Y. pestis strains. The amplicon profiles of the basic Y. pestis subtype were found to be different from such profiles of other Y. pestis subtypes. 相似文献
75.
In neurons, tubulin is synthesized primarily in the cell body, whereas the molecular machinery for neurite extension and elaboration of microtubule (MT) array is localized to the growth cone region. This unique functional and biochemical compartmentalization of neuronal cells requires transport mechanisms for the delivery of newly synthesized tubulin and other cytoplasmic components from the cell body to the growing axon. According to the polymer transport model, tubulin is transported along the axon as a polymer. Because the majority of axonal MTs are stationary at any given moment, it has been assumed that only a small fraction of MTs translocates along the axon by saltatory movement reminiscent of the fast axonal transport. Such intermittent "stop and go" MT transport has been difficult to detect or to exclude by using direct video microscopy methods. In this study, we measured the translocation of MT plus ends in the axonal shaft by expressing GFP-EB1 in Xenopus embryo neurons in culture. Formal quantitative analysis of MT assembly/disassembly indicated that none of the MTs in the axonal shaft were rapidly transported. Our results suggest that transport of axonal MTs is not required for delivery of newly synthesized tubulin to the growing nerve processes. 相似文献
76.
A. I. Usov G. P. Smirnova Z. Kamenarska St. Dimitrova-Konaklieva K. L. Stefanov S. S. Popov 《Russian Journal of Bioorganic Chemistry》2004,30(2):161-167
GC-MS of trimethylsilyl derivatives of the compounds present in the butanolic extract of biomass of brown seaweed Colpomenia peregrina from the Black Sea aided in identification of 24 components, including aliphatic hydroxy and keto and aromatic acids, glycerol, mannitol, floridoside, and monosaccharides. The polysaccharide composition of the biomass was also studied, with high sodium alginate and laminaran contents and a comparatively low level of fucoidan being revealed. The polysaccharides were isolated from the biomass by fractional extraction and purified by precipitation or ion exchange chromatography. The structures of alginic acid and laminaran were deduced from 13C NMR spectra and confirmed, in the case of laminaran, by methylation analysis. The sodium alginate was shown to contain more guluronic (G) than mannuronic acid (M) residues, the M/G ratio being 0.48. Laminaran was demonstrated to be a -glucan with 1 3 linkages in its backbone and 1 6 linkages in its branching points, which is characteristic of brown algae. Fucoidan turned out to be a complex heteropolysaccharide containing, in addition to fucose and sulfate, other neutral monosaccharides and uronic acids. 相似文献
77.
Amino acid residues His and Cys of the NAD-dependent hydrogenase from the hydrogen-oxidizing bacterium Ralstonia eutropha H16 were chemically modified with specific reagents. The modification of His residues of the nonactivated hydrogenase resulted in decrease in both hydrogenase and diaphorase activities of the enzyme. Activation of NADH hydrogenase under anaerobic conditions additionally modified a His residue (or residues) significant only for the hydrogenase activity. The rate of decrease in the diaphorase activity was unchanged. The modification of thiol groups of the nonactivated enzyme did not affect the hydrogenase activity. The effect of thiol-modifying agents on the activated hydrogenase was accompanied by inactivation of both diaphorase and hydrogenase activities. The modification degree and changes in the corresponding catalytic activities depended on conditions of the enzyme activation. Data on the modification of cysteine and histidine residues of the hydrogenase suggested that the enzyme activation should be associated with significant conformational changes in the protein globule. 相似文献
78.
79.
Acid phosphatases differing in both subcellular localization and substrate specificity were isolated for the first time from the liver of the freshwater snail Viviparus viviparus L. by preparative isoelectrofocusing. One of five characterized phosphatases is highly specific to ADP and the others can hydrolyze (at variable rate) a series of natural substrates. A scheme is proposed for the involvement of the studied phosphatases in carbohydrate metabolism. We have also studied some peculiarities of the effect of Cd2+ in vitro and in vivo on the activities of individual components of the acid phosphatase complex and corresponding changes in metabolism of the freshwater snail as a new test-object allowing the estimation of toxicity in water. 相似文献
80.
The activity of mammalian pyruvate dehydrogenase complex (PDC) is regulated by a phosphorylation/dephosphorylation cycle. Dephosphorylation accompanied by activation is carried out by two genetically different isozymes of pyruvate dehydrogenase phosphatase, PDP1c and PDP2c. Here, we report data showing that PDP1c and PDP2c display marked biochemical differences. The activity of PDP1c strongly depends upon the simultaneous presence of calcium ions and the E2 component of PDC. In contrast, the activity of PDP2c displays little, if any, dependence upon either calcium ions or E2. Furthermore, PDP2c does not appreciably bind to PDC under the conditions when PDP1c exists predominantly in the PDC-bound state. The stimulatory effect of E2 on PDP1c can be partially mimicked by a monomeric construct consisting of the inner lipoyl-bearing domain and the E1-binding domain of E2 component. This strongly suggests that the E2-mediated activation of PDP1c largely reflects the effects of co-localization and mutual orientation of PDP1c and E1 component facilitated by their binding to E2. Both PDP1c and PDP2c can efficiently dephosphorylate all three phosphorylation sites located on the alpha chain of the E1 component. For PDC phosphorylated at a single site, the relative rates of dephosphorylation of individual sites are: 2>site 3>site 1. Phosphorylation of sites 2 or 3 in addition to site 1 does not have a significant effect on the rates of dephosphorylation of individual sites by PDP1c, suggesting a random mechanism of dephosphorylation. In contrast, there is a significant decrease in the overall rate of dephosphorylation of pyruvate dehydrogenase by PDP2c under these conditions. This indicates that the mechanism of dephosphorylation of PDC phosphorylated at multiple sites by PDP2c is not purely random. These marked differences in the site-specificity displayed by PDP1c and PDP2c should be particularly important under conditions such as starvation and diabetes, which are associated with a great increase in phosphorylation of sites 2 and 3 of pyruvate dehydrogenase. 相似文献