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2.
D T Beranek C C Weis F E Evans C J Chetsanga F F Kadlubar 《Biochemical and biophysical research communications》1983,110(2):625-631
Human Tamm-Horsfall urinary glycoprotein from an individual of the blood group Sd(a+) phenotype was tritium-labelled by treatment with galactose oxidase and sodium boro[3H]hydride and was then digested with endo-beta-galactosidase. A series of dialysable, labelled fragments was released from which a pentasaccharide was isolated that strongly inhibited the agglutination of Sd(a+) red cells by human anti-Sda serum and hence contained the Sda determinant structure. Reduction, methylation analysis and sequential exo-glycosidase digestion established the structure of the pentasaccharide as: GalNAc beta(1 leads to 4)[NeuAc(2 leads to 3)]Gal beta(1 leads to 4)GlcNAc beta(1 leads to 3)Gal 相似文献
3.
Treatment of human and mouse cell cultures with DNA binding AT-specific compounds and with some base analogues induced distinct undercondensations in several heterochromatic chromosome regions. All those heterochromatic regions undercondensed by AT-specific DNA ligands (distamycin A, DAPI, Hoechst 33258) could be heavily labeled with the silver(Ag)-staining technique; but the heterochromatic regions undercondensed with the cytidine analogue 5-azacytidine were Ag-negative. In metaphase chromosomes from BrdU-treated human cell cultures, the bifilarly substituted chromatids, which show a slight undercondensation, were also Ag-negative. Cytochemical analyses of the Ag-stained undercondensed heterochromatic regions showed that the Ag-stainable material consisted of nonhistone proteins. The mechanism of Ag staining in the undercondensed heterochromatic regions was compared with Ag staining of the nucleolus organizer regions. 相似文献
4.
Arthur E. Weis Warren G. Abrahamson Mark C. Andersen 《Evolution; international journal of organic evolution》1992,46(6):1674-1697
Natural fluctuations in environmental conditions are likely to induce variation in the intensity or direction of natural selection. A long-term study of the insect, Eurosta solidaginins Fitch (Diptera; Tephritidae), which induces stem galls on the perennial herb Solidago altissima (Asteraceae) was performed to explore the patterns of variation in phenotypic selection. The intensity of selection imposed by parasitoids and predators on gallmaking larvae, for gall size, was measured across 16 populations over the course of 4 generations, for a total of 64 population-generations. Directional selection was quantified by i, the selection intensity, and variance selection by j‘, a measure of the intensity of selection on phenotypic variance. Size-dependent attack by parasitoids caused upward directional selection (mean ip = 0.42; SE = 0.023), while size-dependent bird attack favored larvae that induced smaller galls (mean ib = -0.07; SE = 0.013. The mean net directional selection intensity was 0.35 (SE = 0.030), which indicates that insects inducing larger galls are generally favored by selection. The opposing patterns of size-dependent attack resulted in stabilizing selection in half the population generations, with an overall average. j‘ of -0.11 (SE = 0.078). The magnitude of directional selection was strongly influenced by the population mean gall size and weakly by the optimal gall size. The intensity of variance selection was strongly influenced by the shape of the fitness function, with sigmoidal and Gaussian-like shapes causing greater depletion of phenotypic variance. 相似文献
5.
Our previous study indicated that, in the isolated rabbit heart, perfusion with Ca2+ free Krebs Henseleit buffer (KHB) results in increased conversion of exogenous arachidonic acid to PGE2 and 6-keto-PGF1 alpha, probably as the result of increased availability of substrate to cyclooxygenase. Since perfusion with Ca2+ free buffer is known to cause alterations in the cardiac content of various mono- and divalent cations, the present study was performed to determine: a) The relationship between the conversion of exogenous arachidonic acid to prostaglandins and cardiac content of Na+, K+, Ca2+ and Mg2+; and b) Whether enhanced arachidonic acid conversion to prostaglandins during Ca2+ free perfusion is due to reduced incorporation of this fatty acid into tissue lipids. Perfusion of the rabbit heart with Ca2+ free buffer produced a significant reduction in the tissue content of Na+, K+, Ca2+ and Mg2+. However, the production of 6-keto-PGF1 alpha from exogenous arachidonic acid was linearly correlated with tissue Mg2+. These observations, together with our finding that perfusion with Ca2+ free KHB reduced the incorporation of [3H] arachidonic acid into tissue lipids, suggests that Ca2+ free perfusion may, by reducing the activity of arachidonyl CoA synthetase (a Mg2+ dependent enzyme), decrease the acylation of arachidonic acid into lipids, thus increasing the availability of arachidonic acid to cyclooxygenase. 相似文献
6.
I A Cotgreave M Weis M Berggren M S Sandy P W Moldéus 《Journal of biochemical and biophysical methods》1988,16(4):247-254
The derivatisation of intact rat hepatocytes with monobromobimane resulted in rapid labelling of accessible protein thiols in several subcellular fractions. The derivatisation procedure did not cause acute cytotoxicity, nor did it alter the buoyant densities of the fractions or their gross protein compositions. Quantitation of the fluorescence irreversibly associated with the fractions demonstrated considerable intracellular heterogeneity in this pool of thiols. Values were highest in cytosol (ca. 90 nmol/mg protein), intermediate in microsomes (ca. 65 nmol/mg protein) and mitochondria (ca. 45 nmol/mg protein) and lowest in a crude fraction containing both nuclei and plasma membrane (ca. 35 nmol/mg protein). Similar values were obtained from microsomes and cytosol derivatised after fractionation but there were significant increases of ca. 100% in corresponding values from isolated mitochondria and the nuclear/plasma membrane fraction. These results are discussed in terms of the dynamic fluxes in monobromobimane protein thiols during fractionation and the applicability of this noninvasive method to studies of the mechanism(s) of toxicity of reactive xenobiotics and the role(s) of protein thiols in normal cellular function. 相似文献
7.
R L Stevens S Avraham M C Gartner G A Bruns K F Austen J H Weis 《The Journal of biological chemistry》1988,263(15):7287-7291
A cDNA that encodes the peptide core of the secretory granule proteoglycan of the human promyelocytic leukemic cell line, HL-60, has been isolated and analyzed. When human genomic DNA was digested and probed under conditions of low stringency with a rat cDNA that encodes a Mr = 18,600 serine/glycine-rich proteoglycan peptide core in L2 yolk sac tumor cells (Bourdon, M. A., Oldberg, A., Pierschbacher, M., and Ruoslahti, E. (1985) Proc. Natl. Acad. Sci. U.S.A. 82, 1321-1325) and basophilic leukemia-1 cells (Avraham, S., Stevens, R. L., Gartner, M. C., Austen, K. F., Lalley, P. A., and Weis, J. H. (1988) J. Biol. Chem. 263, 7292-7296), a number of DNA fragments were identified. A HL-60 cell-derived cDNA library was therefore screened under conditions of low stringency with the rat probe to identify and isolate a human homologue of this rat proteoglycan peptide core. Analysis of the resulting human cDNA clones indicated that the proteoglycan peptide core that is expressed in HL-60 cells is Mr = 17,600 and contains an 18-amino acid glycosaminoglycan attachment region that consists primarily of alternating serin and glycine. Northern blot analysis of total RNA probed with the human cDNA revealed that the major message for this proteoglycan peptide core in HL-60 cells is approximately 1.3 kilobase pairs in size. When a Southern blot of digested human genomic DNA was probed with the human cDNA, three bands of approximately 6, 9, and 12 kilobase pairs were detected. However, when the Southern blot was probed with the XmnI----3' fragment of this human cDNA, one prominent band was detected, indicating that a single gene encodes this protein in the human. Analysis of the DNA from human/mouse and human/hamster somatic cell hybrids probed with the human cDNA demonstrated that the gene that encodes this molecule resides on human chromosome 10. Because the proteoglycans that are present in the secretory granules of different types of rat and mouse mast cells possess small peptide cores that are rich in serine and glycine, we propose that this HL-60 cell-3 derived cDNA encodes the peptide core of the proteoglycan that is expressed in the secretory granules of this human promyelocytic cell. 相似文献
8.
Microfluorometry of pectic materials in the dehiscence zone of almond (Prunus dulcis [Mill.] DA Webb) fruits 总被引:2,自引:0,他引:2
K G Weis V S Polito J M Labavitch 《The journal of histochemistry and cytochemistry》1988,36(8):1037-1041
We examined the middle lamella and the primary and secondary walls in almond pericarp dehiscence zone cells using a fluorescent cytochemical method which permitted specific, quantitative detection of pectic cell wall materials. Glycol methacrylate-embedded sections were stained with coriphosphine and pectin-specific fluorescent emissions at 630 nm were quantified using green excitation (546 nm). Examination of sectioned material extracted with purified pecto-lytic enzyme preparations was used to demonstrate the relative specificity of the staining reaction for pectic substances. 相似文献
9.
10.
G A Moore M Weis S Orrenius P J O'Brien 《Archives of biochemistry and biophysics》1988,267(2):539-550
Incubation of rat liver mitochondria with benzoquinone derivatives in the presence of succinate plus rotenone has been shown to cause NAD(P)H oxidation followed by Ca2+ release. Further investigation revealed: (1)p-Benzoquinone-induced Ca2+ release was not initiated by a collapse of the mitochondrial membrane potential. However, Ca2+ release and subsequent Ca2+ cycling caused limited increased membrane permeability. (2) p-Benzoquinone-induced NAD(P)H oxidation and Ca2+ release were prevented by isocitrate, 3-hydroxybutyrate, and glutamate but not by pyruvate or 2-oxoglutarate. (3) Inhibition of pyruvate and 2-oxoglutarate dehydrogenases by p-benzoquinone was attributed to arylation of the SH groups of the cofactors, CoA and lipoic acid. Isocitrate dehydrogenase was also inhibited by p-benzoquinone, but the cofactors NAD(P)H and Mn2+ protected the enzyme. Glutamate dehydrogenase was not inhibited by p-benzoquinone. (4) Arylation of mitochondrial protein thiols by p-benzoquinone was associated with an inhibition of state 3 respiration, which was attributed to the inactivation of the phosphate translocase. In contrast, state 4 respiration, and the F1.F0-ATPase and ATP/ADP translocase activities were not inhibited. It was concluded that inhibition of mitochondrial NAD(P)H dehydrogenases by arylation of critical thiol groups will decrease the NAD(P)+-reducing capacity, and possibly lower the NAD(P)H/NAD(P)+ redox status in favor of Ca2+ release. 相似文献