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991.
Cloning and expression of wild-type and mutant forms of the cardiotonic polypeptide anthopleurin B. 总被引:2,自引:0,他引:2
Venom of the sea anemone Anthopleura xanthogrammica contains a minimum of three polypeptide toxins capable of prolonging the repolarization phase of the action potential. A synthetic gene for the most toxic of the Anthopleura toxins, anthopleurin B (ApB), has been designed, synthesized, and expressed as a fusion protein with the gene 9 product of bacteriophage T7 in Escherichia coli. The fusion protein has been purified and its disulfide bonds reoxidized using glutathione redox couples. Upon cleavage with staphylococcal protease, this protocol yields approximately 1 mg of native ApB/liter of original culture. The recombinant protein has been shown to be identical to natural ApB with respect to amino acid composition, amino-terminal sequence, secondary structure, high pressure liquid chromatographic mobility, and biological activity. A second form of ApB containing additional residues of glycine and arginine at its amino terminus has also been characterized. This protein, termed GR-ApB, is identical in specific activity to the wild-type form. This work lays the groundwork for a detailed analysis of ApB structure and action by site-directed mutagenesis. 相似文献
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Adam J. Bell Alice Gallagher Timothy Mottram Annette Lake Eleanor V. Kane Tracy Lightfoot Eve Roman Ruth F. Jarrett 《PloS one》2014,9(11)
A unique feature of both human herpesvirus 6A and B (HHV-6A and B) among human herpesviruses is their ability to integrate into chromosomal telomeres. In some individuals integrated viral genomes are present in the germ-line and result in the vertical transmission of HHV-6; however, little is known about the disease associations of germ-line transmitted, chromosomally integrated HHV-6 (ciHHV-6). Recent publications suggest that HHV-6 is associated with classical Hodgkin lymphoma (cHL). Here we examine the prevalence of ciHHV-6 in 936 cases of cHL and 563 controls by screening with a duplex TaqMan assay and confirming with droplet digital PCR. ciHHV-6 was detected in 10/563 (1.8%) controls and in all but one individual the virus was HHV-6B. Amongst cases 16/936 (1.7%) harboured ciHHV-6, thus demonstrating no association between ciHHV-6 and risk of cHL. 相似文献
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P T Sharpe J A Gallagher B R MacDonald T E Treffry R G Russell 《Cell biochemistry and function》1986,4(1):47-54
Human bone-derived cells, grown in monolayer culture, were dissociated by incubations with trypsin/EDTA and subjected to thin-layer counter-current distribution in a 'low potential' aqueous two-phase system. Two major populations of cells were detected. The number of cells in the second (more hydrophobic) population increased with length of trypsinization and time in culture. Cells allowed to 'regain' surface molecules lost by trypsinization did not produce the second population. Cells occupying the second population after a short period of trypsinization had a lower rate of division than peak 1 cells but showed a higher rate of protein synthesis per rate of division than peak 1 cells. These results show that the cells have markedly different sensitivities to trypsin digestion which may be related to cell division rate of growth. The possible relationship between this and osteoblast development are discussed. 相似文献
997.
Adrenalectomy in the rat was shown to lower seizure threshold measured with the volatile convulsant hexafluorodiethyl ether. Although the expected hyponatraemia and hyperkalaemia were demonstrated in the adrenalectomized rats, there was no associated alteration in Na-K stimulated Mg-ATPase activity either in the whole rat brain or in a microsomal fraction. These results in brain tissue are contrasted with the marked decrease in this enzyme that occurs in kidney tissue of the rat following adrenalectomy. It was suggested that the activity of the enzyme system responsible for active cation transport responds directly in proportion to the work of active transport required by the individual tissue. 相似文献
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