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961.
The effect of Type I interferon on bone resorption was studied by measuring its effect on parathormone-stimulated calcium release from neonatal murine calvaria in vitro. A pure human recombinant leukocyte interferon hybrid of the A and D subtypes was used, which has high antiviral activity on mouse cells. Calcium release was inhibited in a dose dependent fashion with 50% inhibition at about 10(-10) M or 600 U/ml, and the inhibition was reversible. The presence of interferon was required before or during the activation phase of the resorptive response, when the formation of osteoclasts from precursor cells would occur. When added to actively resorbing bone it had no effect. The data suggest that Type I interferon can inhibit the parathormone-regulated development of active osteoclasts, possibly by inhibiting osteoclast precursor differentiation. 相似文献
962.
Salvatore Passarella Anna Atlante Maria Barile Ernesto Quagliariello 《Biochemical and biophysical research communications》1984,121(3):770-778
GABA added to rat brain mitochondria causes oxidation of intramitochondrial NAD(P)H as well as inducing glutamate efflux from the mitochondrial matrix. The rate of NAD(P)H oxidation shows saturation characteristics, depends on GABA transport across the mitochondrial membrane and is inhibited by non-penetrant compounds and by the metal-complexing agent bathophenanthroline. These results show the existence of a specific GABA carrier. Inhibition studies strongly suggest the existence of two separate binding sites, namely the GABA binding site and the dicarboxylates binding site, as well as suggest the presence of a metal ion (ions) at GABA binding site. The occurrence of a GABA/GLUTAMATE antiport is proposed which allows a cyclical route to account for GABA synthesis and degradation in brain. 相似文献
963.
J D Zajac S A Livesey T J Martin 《Biochemical and biophysical research communications》1984,122(3):1040-1046
When the F1-ATPase from the thermophilic bacterium, PS3, was inactivated by 90% with 7-chloro-4-nitro[14C]benzofurazan ([14C]Nbf-Cl) at pH 7.3 and then gel-filtered, 1.25 mols of [14C]Nbf-O-Tyr and less than 0.1 mol of Nbf-N-Lys were formed per mol of enzyme. After adjusting the pH of the gel-filtered, modified enzyme to 9.0 and incubating it for 14 hrs. at 23 degrees C to promote O----N migration, 0.68 mol of Nbf-N-Lys were formed per mol of enzyme while about 16% of the original activity reappeared. Isolation of the subunits after the O----N migration showed that 90% of the incorporated 14C was present in the beta subunit, which contained 0.21 mols of [14C]Nbf-N-Lys per mol. A tryptic peptide which contained the majority of the 14C incorporated into the beta subunit was isolated and subjected to automatic amino acid sequence analysis contained 38 residues. The amino acid sequence immediately around the lysine residue labeled with [14C]Nbf-, K*, was found to be: ...I-G-L-F-G-G-A-G-V-G-K*-T-V-L-I-G... . 相似文献
964.
Characterization of lamin proteins in BHK cells 总被引:5,自引:0,他引:5
Lamins are structural proteins found in rat liver nuclear envelope and are major constituents of the nuclear matrix. 2-D gel electrophoresis indicates that BHK cell nuclear matrix is composed of four major proteins (62 kD, 68 kD, 70 kD and 72 kD). Three of these proteins are very similar to lamins A, B and C of rat liver nuclear envelope according to their molecular mass and isoelectric points. An anti-serum specific to BHK matrix proteins has been raised. On 2-D immunoblot, this serum detects all the 62, 68 and 72 kD polypeptide isovariants but only one of the two isovariants of the 70 kD polypeptide. Rat lamins A, B and C react with the anti-BHK matrix serum. However, when a monoclonal antibody to rat liver lamins A, B and C is used (Burke, B, Tooze, J & Warren, G, EMBO j 2 (1983) 361 [23]), only the 72 kD (lamin A-like) and the 62 kD (lamin C-like) BHK polypeptides are detected. Our results suggest that although a strong similarity exists between BHK and rat lamins, there is no identical cross-reactivity between the two species. 相似文献
965.
Fructose 2,6-bisphosphate, sugar phosphates and adenine nucleotides in the regulation of glucose metabolism in the lactating rat mammary gland 总被引:2,自引:0,他引:2
Fructose 2,6-bisphosphate is present in the rat mammary gland, rising from a value of 1.4 nmol/g in pregnancy to 4.3 nmol/g tissue at 14 days lactation; the equivalent values calculated/ml intracellular water are 5.2 and 11.6 nmol, respectively. The tissue content of fructose 6-phosphate, fructose 1,6-bisphosphate, ATP and phosphoenolpyruvate remain relatively constant in the transition from pregnancy to the height of lactation. The changes in AMP, cyclic AMP, and citrate content of the mammary gland during lactation are such as to promote an increase in fructose 2,6-bisphosphate formation and flux through phosphofructokinase. 相似文献
966.
Transport of the precursor for carbamoyl-phosphate synthetase I into mitochondria in Reuber hepatoma H-35 cells was inhibited by adding monensin or nigericin to the culture medium at a concentration of 0.5 microM, and the enzyme precursor accumulated, mainly in the cytosolic fraction. Accumulated precursor was degraded slowly with a half-life of more than 16 min. Valinomycin, nonactin, A23187, X-537A (lasalocid), bromo-lasalocid, and carbonyl cyanide m-chlorophenylhydrazone did not exhibit these effects at concentrations at which they did not inhibit protein synthesis of the cells. 相似文献
967.
Conservation of interphase chromatin nonhistone antigens as components of metaphase chromosomes 总被引:1,自引:0,他引:1
K W Adolph 《FEBS letters》1984,165(2):211-215
The degree of conservation of HeLa interphase chromatin nonhistone antigens among the nonhistones of isolated metaphase chromosomes was determined with immunological procedures. Proteins were separated on SDS-polyacrylamide gels and electrophoretically transferred to diazophenylthioether (DPT)-paper, which was then overlaid with antiserum to chromatin from interphase nuclei. The bound antibodies were detected with 125I-labeled protein A. Alternatively, polyacrylamide gels were directly overlaid with antiserum and with 125I-protein A. Densitometry of autoradiograms and stained gels revealed the degree of conservation of nonhistone antigenic determinants from interphase to metaphase to be over 90% for chromatin. 相似文献
968.
Homogenates of hypocotyls of light-grown mung-bean (Vigna radiata (L.) Wilczek) seedlings catalyzed the formation of 1-(malonylamino)cyclopropane-1-carboxylic acid (MACC) from the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) and malonyl-coenzyme A. Apparent Km values for ACC and malonyl-CoA were found to be 0.17 mM and 0.25 mM, respectively. Free coenzyme A was an uncompetitive inhibitor with respect to malonyl-CoA (apparent Ki=0.3 mM). Only malonyl-CoA served as an effective acyl donor in the reaction. The d-enantiomers of unpolar amino acids inhibited the malonylation of ACC. Inhibition by d-phenylalanine was competitive with respect to ACC (apparent Ki=1.2 mM). d-Phenylalanine and d-alanine were malonylated by the preparation, and their malonylation was inhibited by ACC. When hypocotyl segments were administered ACC in the presence of certain unpolar d-amino acids, the malonylation of ACC was inhibited while the production of ethylene was enhanced. Thus, a close-relationship appears to exist between the malonylation of ACC and d-amino acids. The cis- as well as the trans-diastereoisomers of 2-methyl- or 2-ethyl-substituted ACC were potent inhibitors of the malonyltransferase. Treatment of hypocotyl segments with indole-3-acetic acid or CdCl2 greatly increased their content of ACC and MACC, as well as their release of ethylene, but had little, or no, effect on their extractable ACC-malonylating activity.Abbreviations ACC
1-aminocyclopropane-1-carboxylic acid
- MACC
1-(malonylamino)-cyclopropane-1-carboxylic acid
Dedicated to Professor Dr. Hubert Ziegler on the occasion of his 60th birthday 相似文献
969.
Systemic effects of chronically administered methyl prednisolonate and methyl 17-deoxyprednisolonate
The systemic activities of methyl prednisolonate and methyl 17-deoxyprednisolonate (1) were studied in rats. Methyl 17-deoxyprednisolonate produced significant changes in the amount of sodium ion (decreased) and potassium ion (increased) in urine; however, methyl prednisolonate had no effect on electrolyte balance. Both methyl prednisolonate and methyl 17-deoxyprednisolonate had no effect on liver glycogen content, plasma corticosterone level and relative adrenal weight. In contrast, the parent compound prednisolone caused a significant decrease in liver glycogen content, plasma corticosterone level and relative adrenal weight. 相似文献
970.
K. Kitamura C. S. Davies N. C. Nielsen 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1984,68(3):253-257
Summary A cultivar lacking the glycinin subunit A5A4B3 (Raiden) was crossed with one lacking the -subunit of -conglycinin (Keburi). Analysis of F2 and F3 progeny indicated that the missing bands of the A5A4B3 and the -subunit were each controlled by a recessive allele of two independently segregating genes. Gene symbols Gy
4/gy
4 and Cgy
1/cgy
1 were proposed for the genes which confer the presence or absence of the glycinin and conglycinin subunits, respectively.Cooperative research of USDA-ARS and the Indiana Agric. Exp. Stn., Purdue Univ., West Lafayette, IN 47907, USA. Indiana Agric. Exp. Stn. Journal Article 9675. Financial support from the American Soybean Association Research Foundation is gratefully acknowledged 相似文献