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991.
T Kaidoh S Natsuume-Sakai M Takahashi 《Journal of immunology (Baltimore, Md. : 1950)》1981,126(2):463-467
A simple, 3-step method was described for purification of murine C4 binding protein (C4-bp), a recently recognized serum protein that functions as one of the regulatory proteins of the complement system. The method consists of 1) affinity chromatography using TNBS-BGG-conjugated Sepharose beads, 2) gel filtration on a Sepharose 6B column, and 3) heparin-Sepharose chromatography. By this method, milligram quantities of C4-bp can be easily purified by more than 500-fold from EDTA-serum of various mouse strains, and the whole purification process can be completed within 1 wk. The overall yield of C4-bp is about 15%. The C4-bp thus prepared is homogeneous as judged by SDS-polyacrylamide gel electrophoresis and immunelectrophoresis. The purified mouse C4-bp showed physicochemical properties very similar to those described for human C4-bp. Like human C4-bp, mouse C4-bp is composed of several apparently identical subunits of the m.w. of 80,000. However unlike the human counterpart, the subunits of mouse C4-bp are not linked by disulfide bonds but are connected by non-covalent forces that can be disrupted by SDS. The purified mouse C4-bp retained binding affinity for C4 and showed unaltered antigenicity. Immunization of rabbits with the purified mouse C4-bp resulted in the production of potent and monospecific antisera. 相似文献
992.
I A Shabarov S N Rumiantsev V F Pospelov 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1985,(6):3-6
As the result of the study of tetanolysin-producing Clostridium tetani strains, their populations have been found to be markedly heterogeneous with respect to the hemolytic activity of clone cultures. On the basis of normal and dialyzed cultures of selected variants with maximum activity the preparations of tetanolysin have been obtained, and their hemolytic activity and antigenic properties have been studied. Antihemolytic rabbit sera have also been obtained and characterized. Partially purified preparations of tetanolysin with high hemolytic activity have been obtained by the fractionation of C. tetani dialyzed cultures with ammonium sulfate. 相似文献
993.
Cloning and expression of the Erwinia chrysanthemi asparaginase gene in Escherichia coli and Erwinia carotovora 总被引:1,自引:0,他引:1
A genomic library of Erwinia chrysanthemi DNA was constructed in bacteriophage lambda 1059 and recombinants expressing Er. chrysanthemi asparaginase detected using purified anti-asparaginase IgG. The gene was subcloned on a 4.7 kb EcoRI DNA restriction fragment into pUC9 to generate the recombinant plasmid pASN30. The position and orientation of the asparaginase structural gene was determined by subcloning. The enzyme was produced at high levels in Escherichia coli (5% of soluble protein) and was shown to be exported to the periplasmic space. Purified asparaginase from E. coli cells carrying pASN30 was indistinguishable from the Erwinia enzyme on the basis of specific activity [660-700 units (mg protein)-1], pI value (8.5), and subunit molecular weight (32 X 10(3]. Expression of the cloned gene was subject to glucose repression in E. coli but was not significantly repressed by glycerol. Recombinant plasmids, containing the asparaginase gene, when introduced into Erwinia carotovora, caused increased synthesis of the enzyme (2-4 fold higher than the current production strain). 相似文献
994.
A nuclear specific glycoprotein representative of a unique pattern of glycosylation 总被引:12,自引:0,他引:12
Whole rat liver nuclei were reacted with UDP-[14C]galactose in the presence of bovine beta(1----4) galactosyltransferase. The reaction mixture was electrophoresed on a reducing sodium dodecyl sulfate-polyacrylamide gel. Autoradiograms of the gel demonstrated a major labeled broad band migrating with an apparent molecular weight of 65,000-66,000. A number of other less prominently labeled bands were also present. The labeled 65,000-66,000 band when cut from the gel and subjected to alkaline reduction while in the gel matrix exclusively yielded a 14C-labeled disaccharide that co-migrated with a [14C]Gal-GlcNAcol standard in descending paper chromatography. Treatment of this disaccharide with beta-galactosidase (beta-D-galactoside galactohydrolase; EC 3.2.1.23) from Aspergillus niger removed all the [14C]galactose label. Treatment of the labeled 65,000-66,000 polypeptide with Endoglycosidase F, however, did not remove the [14C]galactose label. Western transfer blots of sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels performed with horseradish peroxidase-labeled succinyl wheat germ agglutinin, a lectin specific for GlcNAc, on unlabeled nuclei revealed a dominant band at 63,000-64,000. Subjecting 14C-labeled nuclei to this procedure resulted in a shift of the major horseradish peroxidase-labeled succinyl wheat germ agglutinin band to 65,000-66,000. The shifted band was coincident with the [14C]galactose band as visualized on an autoradiogram. A survey of other rat tissue nuclei revealed the same spectrum of [14C]galactose acceptor proteins with a dominant 65,000-66,000 galactose-labeled band. 相似文献
995.
996.
T. V. Fedorov V. I. Korobov V. G. Nazarov A. E. Smolkina V. A. Shmelev 《Applied Biochemistry and Microbiology》2010,46(2):226-229
Hybrid protein, cancer necrosis factor thymosin-α1 (TNF-T), when synthesizing in strain-producer of Escherichia coli SG200-50 with plasmid pThy315, was a part of “inclusion bodies” mostly in the form of a high-molecular complex with other proteins due to the S-S bonds formation. An approach of purification of TNF-T has been proposed, which is based on the destruction of the complex in the presence of sodium dodecylsulfate (DDS-Na) and dithiotreitol (DDT) followed by gel-filtration on Sephadex G-100 and renaturation by ultrafiltration on hollow fibers. The method allows the isolation of electrophoretically homogeneous TNF-T containing no DDS-Na and having high cytotoxic activity against cancer cells of mouse adenocarcinome L-929. The yield of TNF-T achieved 80% relative its content in biomass and 30% relative the total protein. 相似文献
997.
M Irving 《BMJ (Clinical research ed.)》1981,283(6295):847-849
998.
Immediate fragmentation of parental DNA by near-ultraviolet irradiation at 313 nm was measured in cultured skin fibroblasts from normal individuals, patients with Xeroderma pigmentosum of complementation group A (XPA) and Xeroderma pigmentosum variants (XPV) by the alkaline elution procedure. For a dose of 2.25 KJm?2 given at Oo fragmentation was comparable in all cell strains. However, fragmentation was strongly increased relative to Oo in XPV but not in normal fibroblasts and the XPA strains when irradiation was carried out at 37o. From our results it appears that a step in the repair of DNA is abnormal in XPV. 相似文献
999.
ALEXANDRA G. PONETTE‐GONZÁLEZ KATHLEEN C. WEATHERS LISA M. CURRAN 《Global Change Biology》2010,16(3):946-963
Land‐cover change can alter the spatiotemporal distribution of water inputs to mountain ecosystems, an important control on land‐surface and land‐atmosphere hydrologic fluxes. In eastern Mexico, we examined the influence of three widespread land‐cover types, montane cloud forest, coffee agroforestry, and cleared areas, on total and net water inputs to soil. Stand structural characteristics, as well as rain, fog, stemflow, and throughfall (water that falls through the canopy) water fluxes were measured across 11 sites during wet and dry seasons from 2005 to 2008. Land‐cover type had a significant effect on annual and seasonal net throughfall (NTF <0=canopy water retention plus canopy evaporation; NTF >0=fog water deposition). Forest canopies retained and/or lost to evaporation (i.e. NTF<0) five‐ to 11‐fold more water than coffee agroforests. Moreover, stemflow was fourfold higher under coffee shade than forest trees. Precipitation seasonality and phenological patterns determined the magnitude of these land‐cover differences, as well as their implications for the hydrologic cycle. Significant negative relationships were found between NTF and tree leaf area index (R2=0.38, P<0.002), NTF and stand basal area (R2=0.664, P<0.002), and stemflow and epiphyte loading (R2=0.414, P<0.001). These findings indicate that leaf and epiphyte surface area reductions associated with forest conversion decrease canopy water retention/evaporation, thereby increasing throughfall and stemflow inputs to soil. Interannual precipitation variability also altered patterns of water redistribution across this landscape. Storms and hurricanes resulted in little difference in forest‐coffee wet season NTF, while El Niño Southern Oscillation was associated with a twofold increase in dry season rain and fog throughfall water deposition. In montane headwater regions, changes in water delivery to canopies and soils may affect infiltration, runoff, and evapotranspiration, with implications for provisioning (e.g. water supply) and regulating (e.g. flood mitigation) ecosystem services. 相似文献
1000.