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931.
B.A. Jakschik L.H. Lee G. Shuffer C.W. Parker 《Prostaglandins & other lipid mediators》1978,16(5):733-748
Rat basophilic leukemia (RBL-1) cells metabolized arachidonic acid through more than one enzymatic pathway. The major cyclooxygenase product was prostaglandin (PG) D2 as established by chromatographic and chemical behavior and the effect on platelet aggregation. PGD2 formation from exogenous arachidonic acid was inhibited by indomethacin, 1 μg/ml. RBL-1 incubated with exogenous arachidonic acid also formed SRS-A the synthesis of which was not inhibited by indomethacin. However, the SRS-A activity was blocked by the specific receptor antagonist FPL 55712. [14C]arachidonic acid was effectively incorporated into the phospholipids of RBL-1 cells. Challenge of such prelabelled cells or unlabelled cells with A 23187 caused release of PGD2, SRS-A and another presently unidentified product. However, with A 23187 as a stimulus, the RBL-1 cyclo-oxygenase could not be blocked by low concentrations of indomethacin. This work further substantiates our earlier findings that SRS-A formed from arachidontic acid is not a cyclooxegenase product. 相似文献
932.
ROBERT K. PECK 《The Journal of eukaryotic microbiology》1978,25(2):186-198
SYNOPSIS The membranes, epiplasm, and fiber systems are described in the somatic cortex of Glaucoma chattoni strain HZ-1. Kinetodesmal fibers, postciliary and transverse microtubular ribbons, basal microtubules, transverse fibers and transverse accessory material are associated with kinetosomes. Longitudinal microtubular ribbons and mitochondria occur interkinetally. In the buccal cortex, the membranes, epiplasm and fibers of the 3 membranelles, the paroral kinety, the ribbed wall, and the cytostome are described. Comparisons between G. chattoni and other ciliates reveal ultrastructural differences of possible systematic significance. In the somatic cortex of this and other tetrahymenines. Iongitudinal microtubular ribbons and basal microtubules occur concurrently. In the buccal cortex, alveoli are absent in tetrahymenine membranelles. A table is presented of the fiber systems associated with single somatic kinetosomes of various ciliates whose cortical ultrastructure has been studied to date. 相似文献
933.
H B Osborne 《FEBS letters》1977,84(2):217-220
934.
935.
D Mark-Malchoff G V Marinetti J D Hare A Meisler 《Biochemical and biophysical research communications》1977,75(3):589-597
Analysis of the lipids of normal hamster embryo fibroblasts and polyoma virus transformed fibroblasts shows a decrease in phosphatidylcholine and phosphatidylethanolamine and a marked increase in a threonine phospholipid after transformation. Transformed cells also react differently with fluorodinitrobenzene and trinitrobenzenesulfonate. phosphatidylethanolamine of transformed cells reacts to a greater extent with both probes. Phosphatidylserine and the threonine phospholipid of both cells do not react with trinitrobenzenesulfonate. The threonine phospholipid is provisionally identified as phosphatidylthreonine. 相似文献
936.
In an attempt to deduce the physiological basis of proline excretion in argD
– strains of Escherichia coli K12, several properties of an argD
+ (nonexcreting) and an argD
– (excreting) derivative were compared. No difference was found in the transport or in the utilization of either proline or its immediate precursor, 1-pyrroline-5-carboxylate (PCA). Furthermore, no differences were found in the physical or kinetic properties of partially purified preparations of the enzyme mediating the final step in proline biosynthesis, PCA reductase. The specific activity of PCA reductase was, however, consistently higher in crude extracts prepared from the argD
– mutant.This work was supported by grants from the National Institutes of Allergy and Infectious Diseases (Public Health Service No. AI-10862) and The University of Connecticut Research Foundation (to C. M. B.). J. J. R. was supported by an NDEA Predoctoral Fellowship. 相似文献
937.
Ade–H and ade–I are two auxotrophic mutants of Chinese hamster ovary (CHO-K1) cells which specifically require adenine as the purine source to grow. The enzymatic defects of these mutants were examined in cell-free extracts. It was found that ade–H did not have any detectable adenylosuccinate synthetase activity and ade–I was defective in the adenylosuccinate lyase enzyme. The relevance of adenine-requiring mutants to the study of the regulation of purine metabolism in mammalian cells is discussed.This work was supported by research grants from the National Institute of Aging (AG00029) and the National Foundation, March of Dimes (1-423), and by a contract from the Center for Toxicological Research, Food and Drug Administration (72-213). David Patterson is a recipient of a Research Career Development Award from the National Institute of Arthritis, Metabolic and Digestive Diseases (AM00044).Contribution (No. 218) from the Eleanor Roosevelt Institute for Cancer Research. 相似文献
938.
Robert E. Hruska Karen T. Pitman Ellen K. Silbergeld Lynn M. Ludmer 《Life sciences》1982,30(6):547-553
Administration of prolactin to adult male rats, by s.c. injection, significantly increases the density of the striatal dopamine (DA) receptors, without altering the apparent affinity of the receptors for [3H]spiroperidol. Larger doses of prolactin are required to increase the density of the striatal DA receptors in hypophysectomized rates compared to normal rats. These results suggest that prolactin might be the common mediator of the increase in striatal DA receptor density produced by either estrogen or haloperidol administration. Monitoring and/or altering prolactin levels might be informative in neurologic or psychiatric disorders involving striatal DA neurotransmission. 相似文献
939.
Ashis K. Sen Kalyan K. Sarkar Pronobesh C. Mazumder Nilima Banerji Raimo Uusvuori Tapio A. Hase 《Phytochemistry》1982,21(7):1747-1750
Three new tetraoxygenated xanthones (garcinones A, B and C), each disubstituted with C5-units, have been isolated from the chloroform extract of the fruit-hulls of Garcinia mangostana. Their structures were established by a combination of spectral interpretation and chemical correlation. 相似文献
940.
Ferdinand Bohlmann Naleen Borthakur Robert M. King Harold Robinson 《Phytochemistry》1982,21(7):1793-1794
Calea reticulata afforded in addition to known compounds two new sesquiterpenes. These were germacrane and eudesmane derivatives, identified as germacra-4(15),5,10(14)-trien-1-one and 6-epi-β-verbesinol coumarate, respectively. 相似文献