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排序方式: 共有10000条查询结果,搜索用时 7 毫秒
921.
922.
Effector T lymphocyte line cells migrate to the thymus and persist there 总被引:15,自引:0,他引:15
Y Naparstek J Holoshitz S Eisenstein T Reshef S Rappaport J Chemke A Ben-Nun I R Cohen 《Nature》1982,300(5889):262-264
923.
Molecular structure of r(GCG)d(TATACGC): a DNA--RNA hybrid helix joined to double helical DNA 总被引:20,自引:0,他引:20
A H Wang S Fujii J H van Boom G A van der Marel S A van Boeckel A Rich 《Nature》1982,299(5884):601-604
The molecule r(GCG)d(TATACGC) is self-complementary and forms two DNA--RNA hybrid segments surrounding a central region of double helical DNA; its molecular structure has been solved by X-ray analysis. All three parts of the molecule adopt a conformation which is close to that seen in the 11-fold RNA double helix. The conformation of the ribonucleotides is partly determined by water molecules bridging between the ribose O2' hydroxyl group and cytosine O2. The hybrid-DNA duplex junction contains no structural discontinuities. However, the central DNA TATA sequence has some structural irregularities. 相似文献
924.
925.
926.
J. B. Gibson A. V. Wilks G. K. Chambers 《Cellular and molecular life sciences : CMLS》1982,38(6):653-654
Summary A 3rd allele at theAdh locus,Adh
FCh.D., has been found at polymorphic frequencies in natural populations ofD. melanogaster. The ADH-FChD enzyme has properties distinct from those of the 2 more common forms of ADH. TheAdh polymorphism should now be analyzed as a triallelic system. 相似文献
927.
Summary The changes in short-circuit current occurring when one or both solutions bathing the intestine of rat or guinea-pig mounted in flux chambers were recorded. The results with the guinea-pig can be explained in terms of diffusion potentials arising from the ionic replacements, and an electrogenic sodium pump, sensitive to ouabain, in the contraluminal membrane of the cell. In the rat, the situation is more complicated, and the enterocyte probably possesses an electrogenic sodium pump in the brush-border membrane. 相似文献
928.
Summary Melatonin, in concentrations up to 10–3
M, showed no effect on mitosis in cultures of HeLa or KB cells. However, when melatonin at 10–4
M was preincubated with HeLa cells prior to addition of 10–7
M colchicine, a reduction in the mitotic index, in comparison to colchicine alone, was observed.This work was supported by PHS Grant No. CA 16425. 相似文献
929.
J. M. Gelles 《Cellular and molecular life sciences : CMLS》1976,32(7):906-907
Summary Using classical microelectrode techniques in canine cardiac Purkinje fibres, calcium ionophore X-537A was shown to shorten the action potential, hyperpolarizing the membrane and lowering the plateau, suggesting that intracellular calcium controls membrane permeability to potassium in this preparation.This work was supported by grant No. HL 05726 from the U.S. Public Health Service, National Heart Institute, Bethesda, Md.I thank Dr.N. Krasnow for his valuable advice in carrying out this work. 相似文献
930.