排序方式: 共有116条查询结果,搜索用时 62 毫秒
81.
Macurek L Dráberová E Richterová V Sulimenko V Sulimenko T Dráberová L Marková V Dráber P 《The Biochemical journal》2008,416(3):421-430
The molecular mechanisms controlling microtubule formation in cells with non-centrosomal microtubular arrays are not yet fully understood. The key component of microtubule nucleation is gamma-tubulin. Although previous results suggested that tyrosine kinases might serve as regulators of gamma-tubulin function, their exact roles remain enigmatic. In the present study, we show that a pool of gamma-tubulin associates with detergent-resistant membranes in differentiating P19 embryonal carcinoma cells, which exhibit elevated expression of the Src family kinase Fyn (protein tyrosine kinase p59(Fyn)). Microtubule-assembly assays demonstrated that membrane-associated gamma-tubulin complexes are capable of initiating the formation of microtubules. Pretreatment of the cells with Src family kinase inhibitors or wortmannin blocked the nucleation activity of the gamma-tubulin complexes. Immunoprecipitation experiments revealed that membrane-associated gamma-tubulin forms complexes with Fyn and PI3K (phosphoinositide 3-kinase). Furthermore, in vitro kinase assays showed that p85alpha (regulatory p85alpha subunit of PI3K) serves as a Fyn substrate. Direct interaction of gamma-tubulin with the C-terminal Src homology 2 domain of p85alpha was determined by pull-down experiments and immunoprecipitation experiments with cells expressing truncated forms of p85alpha. The combined results suggest that Fyn and PI3K might take part in the modulation of membrane-associated gamma-tubulin activities. 相似文献
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Aims: To develop a PCR-based method for reliable detection of Escherichia coli that enables its differentiation from biochemically and phylogenetically related bacteria. Methods and Results: Using multiplex PCR targeting four genes (cytochrome bd complex, lactose permease, β-d -glucuronidase, and β-d -galactosidase) the possibility of specific detection of various control E. coli strains was tested. It was found that four PCR fragments of the predicted size were observed only for E. coli strains, but not for relatives as close as Shigella sp. or other enterobacteria. Not surprisingly, this method enabled us to identify also E. coli strains which did not exhibit the β-d -glucuronidase activity. Our multiplex PCR was also successfully used for identification of 95 environmental isolates of E. coli. Conclusions: The developed PCR-based method, in which four genes coding for lactose permease, cytochrome bd complex, β-d -glucuronidase, and β-d -galactosidase, serve as target DNA sequences, allows precise and reliable detection of E. coli strains. Significance and Impact of the study: The suggested approach increases the specificity of detection of E. coli since it enables to distinguish E. coli from Shigella sp. and other relative enterobacteria. 相似文献
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Peter Voss Lubica Horakova Manuela Jakstadt Daniela Kiekebusch Tilman Grune 《Free radical research》2013,47(7):673-683
The accumulation of oxidatively damaged proteins is a well-known hallmark of aging and several neurodegenerative diseases including Alzheimer's, Parkinson's and Huntigton's diseases. These highly oxidized protein aggregates are in general not degradable by the main intracellular proteolytic machinery, the proteasomal system. One possible strategy to reduce the accumulation of such oxidized protein aggregates is the prevention of the formation of oxidized protein derivatives or to reduce the protein oxidation to a degree that can be handled by the proteasome. To do so an antioxidative strategy might be successful. Therefore, we undertook the present study to test whether antioxidants are able to prevent the protein oxidation and to influence the proteasomal degradation of moderate oxidized proteins. As a model protein we choose ferritin. H2O2 induced a concentration dependent increase of protein oxidation accompanied by an increased proteolytic susceptibility. This increase of proteolytic susceptibility is limited to moderate hydrogen peroxide concentrations, whereas higher concentrations are accompanied by protein aggregate formation.Protective effects of the vitamin E derivative Trolox, the pyridoindole derivative Stobadine and of the standardized extracts of flavonoids from bark of Pinus Pinaster Pycnogenol® and from leaves of Ginkgo biloba (EGb 761) were studied on moderate damaged ferritin. 相似文献
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C. Nick Pace Hailong Fu Katrina Lee Fryar John Landua Saul R. Trevino David Schell Richard L. Thurlkill Satoshi Imura J. Martin Scholtz Ketan Gajiwala Jozef Sevcik Lubica Urbanikova Jeffery K. Myers Kazufumi Takano Eric J. Hebert Bret A. Shirley Gerald R. Grimsley 《Protein science : a publication of the Protein Society》2014,23(5):652-661
Our goal was to gain a better understanding of the contribution of the burial of polar groups and their hydrogen bonds to the conformational stability of proteins. We measured the change in stability, Δ(ΔG), for a series of hydrogen bonding mutants in four proteins: villin headpiece subdomain (VHP) containing 36 residues, a surface protein from Borrelia burgdorferi (VlsE) containing 341 residues, and two proteins previously studied in our laboratory, ribonucleases Sa (RNase Sa) and T1 (RNase T1). Crystal structures were determined for three of the hydrogen bonding mutants of RNase Sa: S24A, Y51F, and T95A. The structures are very similar to wild type RNase Sa and the hydrogen bonding partners form intermolecular hydrogen bonds to water in all three mutants. We compare our results with previous studies of similar mutants in other proteins and reach the following conclusions. (1) Hydrogen bonds contribute favorably to protein stability. (2) The contribution of hydrogen bonds to protein stability is strongly context dependent. (3) Hydrogen bonds by side chains and peptide groups make similar contributions to protein stability. (4) Polar group burial can make a favorable contribution to protein stability even if the polar groups are not hydrogen bonded. (5) The contribution of hydrogen bonds to protein stability is similar for VHP, a small protein, and VlsE, a large protein. 相似文献
86.
Furman Marek Nemethova Miroslava Macakova Lubica Sihotsky Vladimir Kopolovets Ivan Berek Peter Virag Michal Mucha Rastislav 《Molecular biology reports》2022,49(1):477-485
Molecular Biology Reports - A stroke is an acute damage to a certain area of a nerve tissue of the brain. In developed countries, it ranks second among the most often causes of death and is also... 相似文献
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Znaleziona J Petr J Maier V Knob R Horakova J Smetanova D Sevcik J 《Biomedical papers of the Medical Faculty of the University Palacky, Olomouc, Czechoslovakia》2007,151(1):31-36
BACKGROUnd: The aim of this work was to develop a simple capillary electrophoretic method as the verification and confirmation tool in the screening analysis for amphetamines, opiates, benzodiazepines and cocaine and their metabolites for toxicological applications. METHODS: 50 mM phosphate Tris pH 2.0 with 30% (v/v) of methanol was used as a background electrolyte that enabled fast separation of drugs and their metabolites in saliva and urine. Verification of the data from the electrophoretic method was done by High Performance Thin Layer Chromatography (HPTLC) and the immunochemical screening test QuikScreen. RESULTS: The experimental conditions of the Capillary Electrophoresis (CE) were partially optimized (mainly the influence of concentration and types of additives, e.g. cyclodextrines, organic solvents) and validated; the method was used for analysing samples from drug abusers. CONCLUSIONS: The non-instrumental, immunoassay tests could only confirm qualitative addictions and are mainly employed when the emergency detection of drugs is needed. For quantitative analysis and verification of obtained results the confirmation step is strongly recommended. The simple screening capillary zone electrophoresis method allows recognition of the most abused drugs. The agreement of the results from CE, HPTLC and QuikScreen test was more than 95%. 相似文献
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Surovcikova-Machova L Valachova K Banasova M Snirc V Priesolova E Nagy M Juranek I Soltes L 《General physiology and biophysics》2012,31(1):57-64
Stobadine·2HCl and its two hydrophilic derivatives SM1dM9dM10·2HCl and SME1i-ProC2·HCl were tested in the function of antioxidants on hyaluronan (HA) degradation induced by the Weissberger oxidative system [ascorbate plus Cu(II)]. As a primary method, rotational viscometry was applied, where the substance tested was added before or 1 h after the initiation of HA degradation. The most effective scavengers of ?OH and peroxy-type radicals were recorded to be stobadine·2HCl and SME1i-ProC2·HCl, respectively. The most effective scavenger, determined by applying the ABTS assay, was stobadine·2HCl. 相似文献
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Tomas Kalincik Manuela Vaneckova Michaela Tyblova Jan Krasensky Zdenek Seidl Eva Havrdova Dana Horakova 《PloS one》2012,7(11)