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381.
The effect of 1-β-d-arabinofuranosyl-cytosine on the expression of the common fragile site at 3p14 总被引:1,自引:0,他引:1
Summary The effect of the G2-treatment of 1--d-arabino-furanosyl-cytosine (araC) on the expression of the common fragile site at 3p14 (FRA3B) was studied. A significantly increased frequency of FRA3B induced by G2 treatment of araC was found in the lymphocytes grown in folate-deficient medium (positive rate 100%). A relatively low frequency of FRA3B was also induced in the cultures with folate in four of the seven subjects. These is a synergistic effect between araC and growth in folate-deficient medium on the induction of FRA3B. The results suggest that the DNA lesions related to the expression of FRA3B induce the long-patch repair and that the low DNA polymerase activity and inefficient repair process during G2 phase is involved in the expression of FRA3B. 相似文献
382.
Summary A total of 1242 individuals from six Chinese ethnic groups were studied with respect to the glyoxalase I polymorphism using agarose gel electrophoresis. The GLO1*1 gene frequency and the number of subjects tested in each population are as follows: Uygur 0.2466 (219), Hui 0.1621 (219), Dong 0.1866 (201), Bai 0.1921 (203), Tujia 0.1075 (200), and Maio 0.1600 (200). The differences in the GLO1 gene frequencies between some of these populations are significant. 相似文献
383.
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386.
V F Mashanski? Iu V Markov V Kh Shpunt S E Li A S Mirkin 《Arkhiv anatomii, gistologii i émbriologii》1983,84(3):53-60
Localization and distribution of the gap junctions in the human epidermis have been studied. They are mainly concentrated in the area of biologically active (acupunctive) points and in so called meridians connecting these points. A supposition is made that the gap junction system performs certain integration of the information from the skin surface and its aneural transmission to remote areas. Discovery of a regulated gap junction system in relatively low organized animals (previously described by the authors), as well as revealing of such a system in mammals, makes it possible to suppose that the system is phylogenetically the most ancient one performing a directed transmission of an information simultaneously with and besides the neural system. 相似文献
387.
Band 3 of the human erythrocyte is involved in anion transport and binding of the cytoskeleton to the membrane bilayer. Human erythrocytes were treated to incorporate varying concentrations of DIDS (4,4′-diisothiocyanostilbene-2,2′-disulfonic acid) a non-penetrating, irreversible inhibitor of anion transport, and both functions of Band 3 were analyzed. The rate of efflux of 35SO4. was measured and the binding of cytoskeletal components to the membrane was evaluated by extracting the membranes with 0.1 n NaOH and analyzing for the peptides remaining with the membrane. It was found that 0.1 n NaOH extracts all the extrinsic proteins from membranes of untreated cells, while, in the case of the membranes from cells treated with DIDS, a portion of the cytoskeletal components, spectrin (Bands 1 and 2) and Band 2.1 (ankyrin, syndein) remain with the membrane. The amount of these cytoskeletal components remaining with the membrane depends on the concentrations of DIDS incorporated. The effect of DIDS on the extractability of the spectrin-Band 2.1 complex correlates well with DIDS inhibition of anion transport (r = 0.91). At DIDS concentrations which completely inhibit anion transport, about 10% of total spectrin-Band 2.1 complex remains unextracted. Another anion-transport inhibitor, pyridoxal phosphate, has no effect on binding of the cytoskeleton to the membrane. On the other hand, digestion of DIDS-pretreated intact erythrocytes with Pronase, chymotrypsin, or trypsin releases the tight binding of Band 3 to cytoskeleton on the inside of the membrane. Since trypsin does not hydrolyze Band 3 the data suggest that a second membrane protein which is trypsin sensitive may be involved with Band 3 in cytoskeletal binding. 相似文献
388.
Tissue-specific expression of the rat glutathione S-transferases 总被引:9,自引:0,他引:9
Tissue-specific patterns of rat glutathione S-transferase expression have been demonstrated by in vitro translation of purified poly(A) RNAs and by protein purification. Poly(A) RNAs from six rat tissues including heart, kidney, liver, lung, spleen, and testis were used to program in vitro translation with the rabbit reticulocyte lysate system and [35S]methionine. The glutathione S-transferase subunits synthesized in vitro were purified from the translation products by affinity chromatography on S-hexylglutathione-linked Sepharose 6B columns. The affinity bound fractions were analyzed by Na dodecyl SO4-polyacrylamide gel electrophoresis and fluorography. A subunit of Mr = 22,000 detected in the in vitro translation products of poly(A) RNAs from heart, kidney, lung, spleen, and testis is missing from the translation products of liver poly(A) RNAs. This Mr = 22,000 subunit is present only in the anionic glutathione S-transferase fraction purified from rat heart, kidney, lung, spleen, and testis. Purified anionic glutathione S-transferase from rat liver does not contain this subunit. The relative specific activities toward a dozen different substrates also demonstrate the nonidentity between liver and kidney anionic glutathione S-transferases. In addition, among the glutathione S-transferase subunits expressed in the liver, some of them could not be detected in the other tissues investigated. Our results indicate that tissue-specific expression of rat glutathione S-transferases may occur pretranslationally. 相似文献
389.
J K Li 《Journal of theoretical biology》1983,103(3):333-338
Method in establishing mammalian hemodynamic similarity criteria via the classical allometric approach was examined. Metabolic rate (MR) per unit body weight (w), termed the metabolic turn-over rate (MTR), was found to be linearly related to mammalian resting heart rate (fh). The external ventricular work (EW) per unit body weight was found to be constant among mammalian species. The ratio of (EW/w)/(MTR/fh) is dimensionless, and is about 1/70. This latter qualifies as a new similarity principle. It states that the external ventricular work intensity during each cardiac cycle is directly proportional to the metabolic turn-over rate. 相似文献
390.
Relationship between the Kinetic Properties and the Small Subunit Composition of Nicotiana Ribulose-1, 5-bisphosphate Carboxylase
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Genetic variability in the large and small subunits of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCase) in several Nicotiana species has been characterized by isoelectric focusing patterns. This heritable variation provides an opportunity to examine the functional role of each of these subunits. In this study, specifically designed RuBPCase enzymes composed of identical large subunits but different small subunits were constructed in vivo by interspecific hybridization between the species N. sylvestris, N. tabacum, N. glauca, N. glutinosa, N. plumbaginifolia, and N. tomentosiformis. Small subunit polypeptides were combined to form a sequence of one, two, three, and four polypeptides with the large subunit of N. sylvestris. Kinetic properties of these hybrid enzymes were compared. No differences in the specific activity of either carboxylation or oxygenation nor in Km values for ribulose 1,5-bisphosphate, CO2, or O2 were detected among the RuBPCase enzymes from the various interspecific hybrids. Likewise, the ratio of carboxylation to oxygenation was constant. 相似文献