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131.
132.
Binding sites for atrial natriuretic factor (ANF) in kidneys and adrenal glands of spontaneously hypertensive (SHR) rats 总被引:1,自引:0,他引:1
Binding sites for atrial natriuretic factor (ANF) were studied in kidneys and adrenal glands of 17 week old male spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) normotensive rats by quantitative autoradiography using 125I-ANF-28. In kidney, 125I-ANF-28 binding sites were found in high concentrations in glomeruli and in much lower concentrations in the renal papilla. In adrenal gland, 125I-ANF-28 binding sites were highly localized to the zona glomerulosa and were of moderate density in the inner cortical regions. ANF binding sites did not occur in the adrenal medulla. The maximum binding capacity (Bmax) of 125I-ANF-28 was reduced by 50% in the kidney glomeruli of SHRs compared to WKY controls. In contrast, the affinity constant (Ka) for 125I-ANF-28 was elevated by 100% in kidney glomeruli of SHRs. There were no significant strain differences in values for Bmax or Ka for 125I-ANF-28 binding in the adrenal zona glomerulosa. These findings suggest that the natriuretic and diuretic actions of ANF within kidney glomeruli may be compromised in adult SHR rats and these alterations may contribute to the development and maintenance of hypertension in rats of this strain. 相似文献
133.
High-copy transposon mutagenesis is an effective tool for creating gene disruptions in maize. In order to molecularly define transposon-induced disruptions on a genome-wide scale, we optimized TAIL-PCR to amplify genomic DNA flanking maize Robertson’s Mutator insertions. Sample sequencing from 43 Mutator stocks and the W22 inbred line identified 676 non-redundant insertions, and only a small fraction of the flanking sequences showed significant similarity to maize repetitive sequences. We further designed and tested 79 arbitrary primers to identify 12 primers that amplify all Mutator insertions within a DNA sample at 3.1-fold redundancy. Importantly, the products are of sufficient size to use as substrates or probes for hybridization-based identification of gene disruptions. Our adaptation simplifies previously published TAIL-PCR protocols and should be transferable to other high-copy insertional mutagens. 相似文献
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Chromatographic purification of the chloroplast ATP synthase (CF0-CF1) and the role of CF0 subunit IV in proton conduction 总被引:2,自引:0,他引:2
Chromatographic procedures were developed to purify chloroplast ATP synthase (CF0-CF1) in large amounts and to resolve subunits from this enzyme. The ATP synthase thus obtained has high ATP-Pi exchange and Mg2(+)-ATPase activities upon incorporation into asolectin liposomes. The purity of this preparation was about 95%. By modifications of this chromatographic procedure, we purified subunit IV-deficient CF0-CF1, subunit IV-deficient CF0, and subunit IV. Both ATP-Pi exchange and Mg2(+)-ATPase activities were impaired by depletion of subunit IV from CF0-CF1. Partial restoration of these activities was obtained by reconstituting subunit IV-deficient CF0-CF1 with subunit IV. The impairment of these activities was likely caused by a loss in proton conductivity of CF0 upon removal of subunit IV. The dicyclohexylcarbodiimide-sensitive Mg2(+)-ATPase of subunit IV-deficient CF0-CF1 was not as sensitive to the depletion of subunit IV as ATP-Pi exchange. Nearly 90% of subunit IV could be removed, but Mg2(+)-ATPase activity was inhibited by only 40-60%. Thus subunit IV of CF0-CF1 may not participate directly in proton transfer but may have a role in organizing and/or stabilizing CF0 structure. 相似文献
138.
Mitogenesis induced by calcium-containing crystals. Role of intracellular dissolution 总被引:1,自引:0,他引:1
Hydroxyapatite, like other calcium-containing crystals previously studied by us, is mitogenic for cultured human fibroblasts. This mitogenic effect is not a result of increased ambient calcium concentration due to extracellular crystal dissolution. Synthetic crystals labelled uniformly with calcium 45 (45Ca) undergo endocytosis when incubated with cells and are solubilized. Such solubilization is inhibited by chloroquine or ammonium chloride in concentrations that significantly block the mitogenic effect of crystals but not that of serum. The data suggest that mitogenesis and intracellular crystal dissolution are related phenomena. 相似文献
139.
Ethylene dibromide transformation under methanogenic conditions 总被引:1,自引:0,他引:1
Ethylene dibromide present at a low concentration (less than 100 micrograms/liter) was transformed by reductive dehalogenation under methanogenic conditions in batch bacterial cultures and in a continuous-flow, methanogenic, fixed-film, laboratory-scale column. 相似文献
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