排序方式: 共有117条查询结果,搜索用时 15 毫秒
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Lee IA Popov AM Sanina NM Kostetsky EY Novikova OD Reunov AV Nagorskayaand VP Shnyrov VL 《Acta biochimica Polonica》2004,51(1):263-272
Some physicochemical properties of glycoglycerolipids (monogalactosyldiacylglycerol, digalactosyldiacylglycerol and sulfoquinovosyldiacylglycerol) from the sea algae Laminaria japonica, as well as their ability to become incorporate into immunostimulating complexes (ISCOMs), used as a delivery system of microbial and tumor antigens in vesicular form, were studied. These glycolipids were found to differ essentially in fatty acid composition, unsaturation index and thermotropic behavior. The possibility of ISCOM modification by embedding the glycolipids studied instead of a phospholipid component in vesicles was shown. A preliminary research of the immunogenicity of the pore-forming protein from Yersinia pseudotuberculosis in modified (by monogalactosyldiacylglycerol) and typical (egg phosphatidylcholine) ISCOMs did not reveal a significant enhancement of immune response in comparison with that of isolated protein. 相似文献
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Several mutations are known to increase the thermostability of α-amylase of B. licheniformis and other α-amylases. Site-directed mutagenesis was used to introduce similar mutations into the sequence of the α-amylase gene from mesophilic Bacillus sp. 406. The influence of the mutations on thermostability of the enzyme was studied. It was shown that the Gly211Val and Asn192Phe substitutions increased the half-inactivation temperature (Tm) of the enzyme from 51.94±0.45 to 55.51±0.59 and 58.84±0.68°C respectively, in comparison to the wild-type enzyme. The deletion of Arg178-Gly179 (dRG) resulted in an increase of Tm of the α-amylase to 71.7±1.73°C. The stabilising effect of mutations was additive. When combined they increase the Tm of the wild-type amylase by more than 26°C. Thermostability rates of the triple mutant are close to the values which are typical for industrial heat-stable α-amylases, and its ability to degrade starch at 75°C was considerably increased. The present research confirmed that the Gly211Val, Asn192Phe and dRG mutations could play a significant role in thermostabilization of both mesophilic and thermophilic α-amylases. 相似文献
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Arutyunova EI Danshina PV Domnina LV Pleten AP Muronetz VI 《Biochemical and biophysical research communications》2003,307(3):547-552
Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a protein with various activities far from its enzymatic function. Here, we showed that the oxidation of SH-groups of the active site of GAPDH enhanced its binding with total transfer RNA or with total DNA. Both NAD and NADH-the cofactors of GAPDH-inhibited the GAPDH-RNA (DNA) interaction, though NAD was much less effective than NADH in the case of oxidized GAPDH. Oxidation of GAPDH strongly decreased its affinity to NAD but not to NADH. Immobilized tetramers of GAPDH dissociated into dimers during the incubation with total RNA but not DNA. The staining of HeLa cells with monoclonal antibodies specific to dimers, monomers or the denatured form of GAPDH revealed the condensation of non-native forms of GAPDH in the nucleus. The role of oxidation of GAPDH in the regulation of the quaternary structure of the enzyme and in its interaction with nucleic acids is discussed. 相似文献
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Vera Nagorskaya Anatoliy Reunov Larisa Lapshina Viktoriya Davydova Irina Yermak 《Virologica Sinica》2014,(4)
The effect of chitosan on the development of infection caused by Tobacco mosaic virus(TMV) in leaves of Nicotiana tabacum L. cv. Samsun has been studied. It was shown that the infectivity and viral coat protein content in leaves inoculated with a mixture of TMV(2 μg/mL) and chitosan(1 mg/mL) were lower in the early period of infection(3 days after inoculation), by 63% and 66% respectively, than in leaves inoculated with TMV only. Treatment of leaves with chitosan 24 h before inoculation with TMV also caused the antiviral effects, but these were less apparent than when the virus and polysaccharide were applied simultaneously. The inhibitory effects of the agent decreased as the infection progressed. Inoculation of leaves with TMV together with chitosan considerably enhanced the activity of hydrolases(proteases, RNases) in the leaves, in comparison with leaves inoculated with TMV alone. Electron microscope assays of phosphotungstic acid(PTA)-stained suspensions from infected tobacco leaves showed that, in addition to the normal TMV particles(18 nm in diameter, 300 nm long), these suspensions contained abnormal(swollen, "thin" and "short") virions. The highest number of abnormal virions was found in suspensions from leaves inoculated with a mixture of TMV and chitosan. Immuno-electron microscopy showed that "thin" virus particles, in contrast to the particles of normal diameter, lost the ability to bind to specific antiserum. It seems that the chitosan-induced activation of hydrolases stimulates the intracellular degradation of TMV particles and hence hydrolase activation may be considered to be one of the polysaccharide-mediated cellular defense mechanisms that limit virus accumulation in cells. 相似文献
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C. A. Stein J. Bo Hansen Johnathan Lai SiJian Wu Anatoliy Voskresenskiy Anja H?g Jesper Worm Maj Hedtj?rn Naira Souleimanian Paul Miller Harris S. Soifer Daniella Castanotto Luba Benimetskaya Henrik ?rum Troels Koch 《Nucleic acids research》2010,38(1):e3
For the past 15–20 years, the intracellular delivery and silencing activity of oligodeoxynucleotides have been essentially completely dependent on the use of a delivery technology (e.g. lipofection). We have developed a method (called ‘gymnosis’) that does not require the use of any transfection reagent or any additives to serum whatsoever, but rather takes advantage of the normal growth properties of cells in tissue culture in order to promote productive oligonucleotide uptake. This robust method permits the sequence-specific silencing of multiple targets in a large number of cell types in tissue culture, both at the protein and mRNA level, at concentrations in the low micromolar range. Optimum results were obtained with locked nucleic acid (LNA) phosphorothioate gap-mers. By appropriate manipulation of oligonucleotide dosing, this silencing can be continuously maintained with little or no toxicity for >240 days. High levels of oligonucleotide in the cell nucleus are not a requirement for gene silencing, contrary to long accepted dogma. In addition, gymnotic delivery can efficiently deliver oligonucleotides to suspension cells that are known to be very difficult to transfect. Finally, the pattern of gene silencing of in vitro gymnotically delivered oligonucleotides correlates particularly well with in vivo silencing. The establishment of this link is of particular significance to those in the academic research and drug discovery and development communities. 相似文献
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Mawn TM Popov AV Beardsley NJ Stefflova K Milkevitch M Zheng G Delikatny EJ 《Bioconjugate chemistry》2011,22(12):2434-2443
In this article, the characterization of the first near-infrared (NIR) phospholipase-activated molecular beacon is reported, and its utility for in vivo cancer imaging is demonstrated. The probe consists of three elements: a phospholipid (PL) backbone to which the NIR fluorophore, pyropheophorbide a (Pyro), and the NIR Black Hole Quencher 3 (BHQ) were conjugated. Because of the close proximity of BHQ to Pyro, the Pyro-PtdEtn-BHQ probe is self-quenched until enzyme hydrolysis releases the fluorophore. The Pyro-PtdEtn-BHQ probe is highly specific to one isoform of phospholipase C, phosphatidylcholine-specific phospholipase C (PC-PLC), responsible for catabolizing phosphatidylcholine directly to phosphocholine. Incubation of Pyro-PtdEtn-BHQ in vitro with PC-PLC demonstrated a 150-fold increase in fluorescence that could be inhibited by the specific PC-PLC inhibitor tricyclodecan-9-yl xanthogenate (D609) with an IC(50) of 34 ± 8 μM. Since elevations in phosphocholine have been consistently observed by magnetic resonance spectroscopy in a wide array of cancer cells and solid tumors, we assessed the utility of Pyro-PtdEtn-BHQ as a probe for targeted tumor imaging. Injection of Pyro-PtdEtn-BHQ into mice bearing DU145 human prostate tumor xenografts followed by in vivo NIR imaging resulted in a 4-fold increase in tumor radiance over background and a 2 fold increase in the tumor/muscle ratio. Tumor fluorescence enhancement was inhibited with the administration of D609. The ability to image PC-PLC activity in vivo provides a unique and sensitive method of monitoring one of the critical phospholipase signaling pathways activated in cancer, as well as the phospholipase activities that are altered in response to cancer treatment. 相似文献
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Iván J. Santos-Soto Nataliya Chorna Néstor M. Carballeira José G. Vélez-Bartolomei Ana T. Méndez-Merced Anatoliy P. Chornyy Sandra Pe?a de Ortiz 《PloS one》2013,8(12)
Combinatorial therapies using voluntary exercise and diet supplementation with polyunsaturated fatty acids have synergistic effects benefiting brain function and behavior. Here, we assessed the effects of voluntary exercise on anxiety-like behavior and on total FA accumulation within three brain regions: cortex, hippocampus, and cerebellum of running versus sedentary young adult male C57/BL6J mice. The running group was subjected to one month of voluntary exercise in their home cages, while the sedentary group was kept in their home cages without access to a running wheel. Elevated plus maze (EPM), several behavioral postures and two risk assessment behaviors (RABs) were then measured in both animal groups followed immediately by blood samplings for assessment of corticosterone levels. Brains were then dissected for non-targeted lipidomic analysis of selected brain regions using gas chromatography coupled to mass spectrometry (GC/MS). Results showed that mice in the running group, when examined in the EPM, displayed significantly lower anxiety-like behavior, higher exploratory and risky behaviors, compared to sedentary mice. Notably, we found no differences in blood corticosterone levels between the two groups, suggesting that the different EPM and RAB behaviors were not related to reduced physiological stress in the running mice. Lipidomics analysis revealed a region-specific cortical decrease of the saturated FA: palmitate (C16:0) and a concomitant increase of polyunsaturated FA, arachidonic acid (AA, omega 6-C20: 4) and docosahexaenoic acid (DHA, omega 3-C22: 6), in running mice compared to sedentary controls. Finally, we found that running mice, as opposed to sedentary animals, showed significantly enhanced cortical expression of phospholipase A2 (PLA2) protein, a signaling molecule required in the production of both AA and DHA. In summary, our data support the anxiolytic effects of exercise and provide insights into the molecular processes modulated by exercise that may lead to its beneficial effects on mood. 相似文献
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Yeshchenko Oleg A. Bondarchuk Illya S. Malynych SerhiyZ. Galabura Yuriy Chumanov George Luzinov Igor Pinchuk Anatoliy O. 《Plasmonics (Norwell, Mass.)》2017,12(5):1571-1580
Plasmonics - Laser-driven hybridization of a collective surface plasmon mode of a monolayer of silver nanoparticles has been studied as a function of irradiation power density. Two collective... 相似文献