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141.
S Arnott R Chandrasekaran L C Puigjaner J K Walker I H Hall D L Birdsall R L Ratliff 《Nucleic acids research》1983,11(5):1457-1474
The B form of poly d(GC):poly d(GC) in orthorhombic microcrystallites in oriented fibers has a secondary structure in which a dinucleotide is the repeated motif rather than a mononucleotide as in standard, smooth B DNA. One set of nucleotides (probably GpC) has the same conformations as the smooth form but the alternate (CpG) nucleotides have a different conformation at C3'-O3'. This leads to a distinctive change in the orientation of the phosphate groups. Similar perturbations can be detected in other poly d(PuPy):poly d(PuPy) DNAs such as poly d(IC):poly d(IC) and poly d(AT):poly d(AT) in their D forms which have tetragonal crystal environments. This suggests that such perturbations are intrinsic to all stretches of duplex DNA where purines and pyrimidines alternate and may play a role in the detection and exploitation of such sequences by regulatory proteins. 相似文献
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Biochemical heterogeneity of the Sanfilippo syndrome: preliminary characterization of two deficient factors 总被引:8,自引:0,他引:8
H Kresse U Wiesmann M Cantz C W Hall E F Neufeld 《Biochemical and biophysical research communications》1971,42(5):892-898
Fibroblasts cultured from the skin of Sanfilippo patients show excessive accumulation and prolonged turnover time of sulfated mucopolysaccharide. This abnormality can be corrected by a macromolecular factor contained in the secretions of fibroblasts of differing genotype, as well as in normal human urine. By cross-correction tests, the Sanfilippo fibroblasts can be subdivided into two groups, each deficient in a different factor. Analytical polyacrylamide gel electrophoresis shows the two factors, which are probably proteins, to have a similar molecular weight (ca. 200,000) but to differ in charge at pH 8.5. 相似文献
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146.
Summary Exudate can be obtained from incisions made in the bark of the stem of actively growing Ricinus plants. 14C-labelled assimilates from a fed leaf are rapidly detected in the exudate. This movement was both acropetal and basipetal from the fed leaf, at rates of over 100 cm h-1. Estimated rates within intact plants were 80–84 cm h-1.In contrast with xylem sap obtained from the same plant, the exudate obtained had an alkaline pH (8.2), a high dry matter content (10–12.5%), high sugar content (8–10%) which was predominantly sucrose; high potassium content (60–80 mM) and low calcium content (0.5–1.0 mM).It is concluded, on the basis of the present evidence, that the exudate is a true sample of the sieve tube sap undergoing translocation. 相似文献
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148.
Genetic Analyses of the Polarity Alleles in Recombinants from Mitochondrial Genetic Crosses 总被引:3,自引:1,他引:2
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Neil Howell Ruth M. Hall Anthony W. Linnane H. B. Lukins 《Journal of bacteriology》1974,119(3):1063-1065
A number of minority recombinant and parental types from a heterosexual cross were analyzed for the omega allele they carry. It was found that recombinant progeny can be omega(-), that minority parental types among the progeny can be omega(+) rather than omega(-), and, finally, that certain of the results suggest that the omega locus may not be at the proximal end of the mitochondrial genetic map (Bolotin et al., 1971; Grivell et al., 1973) but rather may lie between the [cap1-r/cap-s] and [ery1-r/ery-s] loci. 相似文献
149.
Regulation of Newly Evolved Enzymes. I. Selection of a Novel Lactase Regulated by Lactose in ESCHERICHIA COLI 总被引:17,自引:2,他引:15
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Thirty-four lactose-utilizing strains of E. coli were selected from a lac Z deletion strain. In 31 of these, the synthesis of the newly evolved lactase is regulated by lactose. The lactase activity in all the strains is indistinguishable from the ebg(+) activity identified by Campbell, Lengyel and Langridge (1973). 相似文献
150.
Rhodopsin biosynthesis in vitro 总被引:7,自引:0,他引:7