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61.
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Cloning and mapping of Saccharomyces cerevisiae photoreactivation gene PHR1. 总被引:9,自引:3,他引:6 下载免费PDF全文
The yeast Saccharomyces cerevisiae, like most organisms, is able to directly repair pyrimidine dimers by using a photoreactivating enzyme and visible light. Cells carrying the phr1 mutation were shown previously to be unable to photoreactivate dimers, but neither the map position nor the primary gene product of the PHR1 gene has been determined. We have cloned this gene and determined its map position. A plasmid containing a 6.4-kilobase yeast DNA insert has been isolated and shown to restore photoreactivation in a phr1 strain. A 3.1-kilobase subclone has also been shown to complement phr1. The original plasmid was targeted to integrate into chromosomal DNA at a site homologous to the insert by cutting within the insert. Two of these integrants have been mapped on the right arm of chromosome XV; the integrants have been further mapped at ca. 13 centimorgans from prt1. It has also been independently determined that phr1 maps at this location. Thus, we have determined the map position of PHR1 and also have shown that the plasmid contains PHR1 rather than a suppressor of the phr1 mutation. 相似文献
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William r. Anderson Willi Frick G.Doyle Daves Douglas F. Barofsky Isomaro Yamaguchi Ding Chang Karl Folkers Sune Rosell 《Biochemical and biophysical research communications》1977,78(1):372-376
Mass spectra of underivatized hexa- and heptapeptide amides related to Substance P have been obtained with a conventional electron ionization mass spectrometer using sample vaporization from a tungsten wire by the technique of rapid heating, proton transfer ionization using ammonia, and photoplate recording of spectra. These spectra exhibit little evidence of sample pyrolysis and are readily interpreted to yield amino acid sequences. 相似文献
65.
The association of [3H] [D-Ala2, D-Leu5] enkephalin ([3H]DADLE]) with mouse neuroblastoma cells (N4TG1) was investigated. Under identical conditions the time course, dose response curve and temperature dependence for ligand uptake were similar to those for ligand-induced receptor loss (down regulation). Uptake of [3H]DADLE was inhibited by opiate ligands as well as by the metabolic inhibitors sodium azide and 2,4 dinitrophenol. Comparison of the effects of these inhibitors on receptor binding, ligand uptake and receptor loss indicated that these cells accumulate [3H]DADLE in excess of their surface receptor number. The data suggest that receptor recycling occurs and that ligand is internalized via receptor mediated endocytosis. 相似文献
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Guinea pig sperm respiration was determined in minimal capacitation medium (MCM) with different energy sources. The ZO2 observed for spermatozoa suspended in media containing pyruvate and lactate was 35.7 +/- 5.9, pyruvate alone, 27.9 +/- 3.8 and D-glucose alone 3.4 +/- 1.1. When D-glucose was added to spermatozoa rapidly respiring in media containing pyruvate as the only exogenous energy source, an immediate suppression in respiration was observed. Further reduction was caused by continued addition of D-glucose. Fructose and mannose also produced a suppression in respiratory rate. However, lactose, fucose, sucrose, L-glucose, and galactose did not alter the respiratory rate. The suppression of respiration by metabolizable sugars is paralleled by a suppression of acrosome reaction in guinea pig spermatozoa. The possibility that suppression of respiration is the mechanism for retardation of capacitation and the subsequent acrosome reaction by D-glucose and other metabolizable sugars is suggested. 相似文献
68.
Chang CW 《Plant physiology》1979,63(5):973-977
During cotton leaf development, starch accumulation was characterized by an initial rise to a maximum at the second to the fourth leaf from the apex. Then, starch content progressively decreased with leaf age. Starch accumulation was inversely related to the ratio of amylopectin to amylose. Differences between leaves in this ratio resulted from variations in both amylose and amylopectin levels. Fluctuations in amylose levels were more extreme than those of amylopectin. 相似文献
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