共查询到20条相似文献,搜索用时 0 毫秒
1.
OKY-1581 is an effective inhibitor of thromboxane synthesis and . The generation of thromboxane B2 (TxB2), prostaglandin E (PGE) and prostaglandin F (PGF) was measured following clotting and during platelet aggregation induced by collagen. The presence of OKY 1581 either or caused a reduction in TxB2 generation during clotting and platelet aggregation with a concomitant increase in PGE and PGF. The effect could be observed two hours after oral or subcutaneous administration of 5 to 100 mg per rabbit and lasted for 24 to 48 hours. The reduction in TxB2 was not accompanied by an inhibition of clotting or platelet aggregation. OKY-1581 appears to be a suitable agent for studying the role of TxB2 in atherosclerosis. 相似文献
2.
Mary Ann Dombrink-Kurtzman William E. Dick Kermit A. Burton Martin C. Cadmus Morey E. Slodki 《Biochemical and biophysical research communications》1983,111(3):798-803
Evidence is presented for the presence of a new lectin activity in soybean seeds [ (L.) Merrill] that has specificity towards the 4-O-methyl--glucurono--rhamnan exopolysaccharide produced by certain strains of . Bacterial agglutination and precipitin reactions revealed the lectin activity in phosphate-buffered saline extracts of seeds of all cultivars tested, including the “lectinless” varieties. Reaction of such extracts with carbohydrate haptens demonstrated that the specificity of the binding was towards 4--methyl--glucuronic acid, -glucuronic acid and their methyl glycosides. 相似文献
3.
Guanylate cyclase from crude homogenates of vegetative has been characterized. It has a pH optimum of 8.0, temperature optimum of 25°C and requires 1 mM dithiothreitol for optimal activity. It strongly prefers Mn++ to Mg++ as divalent cation, requires Mn++ in excess of GTP for detectable activity, and is inhibited by high Mn++ concentrations. It has an apparent Km for GTP of approximately 517 μM at 1 mM excess Mn++.The specific activity of guanylate cyclase in vegetative homogenates is 50–80 pmoles cGMP formed/min/mg protein. Most of the vegetative activity is found in the supernatant of a 100,000 x g spin (S100). The enzyme is relatively unstable. It loses 40% of its activity after 3 hours storage on ice. Enzyme activity was measured from cells that had been shaken in phosphate buffer for various times. It was found that the specific activity changed little for at least 8 hours. Cyclic AMP at 10?4 M did not affect the guanylate cyclase activity from crude homogenates of vegetative or 6 hour phosphate-shaken cells. 相似文献
4.
Both pairs of -ll-desoxy- and -13---15, 16-dihydroxyprostaglandins have been synthesized via 1,4-conjugate additions of an appropriately functionalized -vinyl cuprate to the requisite cyclopentenone. These prostaglandin analogs are considerably less potent than PGE2 as gastric secretion inhibitors or as bronchodilators. 相似文献
5.
This case report addresses the occurrence of Brucellosis and its effect on the cattle in developing countries. Three Zebu bulls () are presented and the clinical and pathologic signs are described. Conception rates declined following an abortion storm in one herd and without prior abortions in another herd. Semen collected by electro-ejaculation was found to be azoospermic or with very few spermatozoa. was isolated from seminal vesicles, testes and epididymides. Organs affected and showing microscopic lesions were testes, epididymides and seminal vesicles. The latter were not consistently affected. None of the bulls showed impairment of libido or breeding capacity. 相似文献
6.
Yuji Kamiya Akira Sakurai Nobutaka Takahashi 《Biochemical and biophysical research communications》1980,94(3):855-860
Rhodotorucine which induces mating tube formation of cells in is metabolized rapidly by cells. By use of labeled rhodotorucine , the degradation was found to be proteolytic. Two peptide fragments Tyr-Pro-Glu-Ile-Ser-Trp-Thr-Arg and Asn-Gly-Cys(S-farnesyl) were identified as the metabolites. Proteolysis of the pheromone mainly occurred on the cell surface. Culture filtrate of cells at log phase did not metabolize rhodotorucine . 相似文献
7.
Evelyn A. Devine Mary C. Moran Peter J. Jederlinic Anthony J. Mazaitis Henry J. Vogel 《Biochemical and biophysical research communications》1975,67(4):1589-1593
The transducing phage λd, carrying a portion of the chromosome including , is derived from the heat-inducible, lysis-defective strain λy199, which has the and deletions. Cleavage of λy199 DNA by RI endonuclease, followed by agarose slab gel electrophoresis, results in bands corresponding to the known C, D, E, and F segments of λ, and a segment A′ (A plus B minus minus , the cleavage site between A and B being eliminated). Cleavage of λd DNA by RI yields the expected D, E, and F segments of λ and four other segments, termed 14-1 through 14-4, whose length is 17.5, 6.2, 3.0, and 2.0 kilobases, respectively, as determined by electron microscopy and corroborated by electrophoretic mobility. Heteroduplex analysis shows that the cluster is on the 14-1 segment. 相似文献
8.
Uterine stage embryos collected from the hamster (8-cell) and cow (morula, early blastocyst) were monitored for development (embryo culture) and (embryo transfer) following premature removal of the zona pellucida.Removal of the zona pellucida did not significantly affect development to the blastocyst stage of (1) 8-cell hamster embryos (zonae removed by a combined enzymic-mechanical procedure), (2) bovine morulae (zonae removed by mechanical means only) (3) early bovine blastocysts (zonae removed by the enzymic-mechanical technique).Zona-free hamster embryos formed significantly fewer viable fetuses than did zona-intact embryos. The lower incidence of fetal development observed following transfer of zona-free 8-cell hamster embryos may have resulted in part from the formation of chimeras by fusion of these embryos . Such fusion was observed to occur between zona-free embryos placed in close proximity. The proportion of pregnancies resulting from transfer of bovine blastocysts cultured from zona-free morulae was similar to that of zona-intact embryos.In this study we have demonstrated that (1) enzymic and mechanical procedures used to remove zonae pellucidae from uterine-stage hamster and bovine embryos do not adversely affect subsequent development of these embryos and and (2) zonae pellucidae are not required for normal development of these embryos. These findings have implications for microsurgery of mammalian embryos and for embryo transfer. 相似文献
9.
G. Brunet S. Charleson A.W. Ford-Hutchinson 《Prostaglandins & other lipid mediators》1985,29(6):921-932
Chopped lung from inbred hyperreactive rats was challenged with antigen following active on passive sensitization and supernatants were assayed for the presence of leukotrienes (LTs) by radioimmunoassay. Dose-related increases in the release of LTC4- and LTB4-immunoreactive material were obtained with significantly more material being released following passive sensitization. Chromatographic analysis indicated the presence of LTB4, LTC4 and LTE4. When LT release inbredred rats was compared to Sprague-Dawley or Fischer rats, the amounts released were as follows: Inbred > Sprague-Dawley > Fischer. It was concluded that the release of LTs in the three strains correlated with the degree of non-specific bronchial hyperreactivity. 相似文献
10.
J.A. Pérez-González A. Jiménez 《Biochemical and biophysical research communications》1984,125(3):895-901
The paromomycin producing organism is resistant to this antibiotic and contains a phosphotransferase which inactivates paromomycin. The gene encoding this enzyme has been inserted in the vector pIJ702 and then cloned in , selecting for paromomycin-resistance. Three plasmids have been isolated and one of them, pMJ1, contains a 2.2 kb insert with a single HindIII restriction site. Insertion of foreign DNA in this site blocks the expression of the phosphotransferase enzyme indicating that it is within the cloned gene. These findings provide a new dominant selective marker for cloning vectors with the versatility of insertional inactivation. 相似文献
11.
Yolk free blastoderms of chick embryo were incubated 3 or 22 hours with labeled pregnenolone, progesterone, 17-hydroxyprogesterone, dehydro-epiandrosterone, androstenedione, testosterone and estradiol-17β. Metabolites and unconverted substrates were found both in the incubation medium and in the cells. Enzymes responsible for identified conversions were: 17α-hydroxylase, 17-20-desmolase, Δ53β- and 3α-hydroxysteroid dehydrogenase, 17β-hydroxysteroid dehydrogenase and 5α- and 5β-reductase. The results suggest that the steroid metabolizing enzyme activities found may reflect a more general ability of early embryonic cells. 相似文献
12.
Ronald M. Hamelik Mead M. McCabe 《Biochemical and biophysical research communications》1982,106(3):875-880
An inhibitor of , endodextranase was detected in proteins prepared from batch cultures of , strains representing serotypes through . Affinity chromatography of strain 6715-49 proteins, which apparently were free of endodextranase activity, yielded an active endodextranase and, in a separate peak, the endodextranase inhibitor. The presence of the inhibitor in culture fluids accounts for the absence of endodextranase activity in batch-grown cultures of , known to produce this enzyme. 相似文献
13.
Werner Goebel 《Biochemical and biophysical research communications》1973,51(4):1000-1007
The dependence of the replication of several plasmids on the chromosome-determined initiation products, A and C, has been studied. The initiation of the replication of E1 DNA requires the chromosomal A product. In contrast two de-repressed transfer factors ( and 152) seem to determine a corresponding plasmid-specific factor. The C-product is necessary for the ordered initation of all plasmids studied. The addition of low concentrations of chloramphenicol leads to a relaxed replication of E1 DNA at the restrictive temperature in A-mutants, but not in C-mutants. 相似文献
14.
Daniel H. Riddick Anthony A. Luciano William F. Kusmik Ila A. Maslar 《Life sciences》1978,23(19):1913-1921
Relatively large amounts of immunoreactive prolactin were measured in homogenates of human decidual tissue obtained immediately after delivery of normal term pregnancies. In order to study the release and possible synthesis of prolactin by this tissue, explants of decidua were incubated for 24 hours at 37°C in oxygenated Gey's buffer containing 20% fetal calf serum. When cycloheximide was added to the medium in concentrations sufficient to prevent protein synthesis, 85–90% of the prolactin present in the tissue was released into the medium during the first 3 hours of incubation. No additional prolactin accumulated in either the medium or the tissue during the remainder of the incubation period. In the absence of cycloheximide, the prolactin concentration in the medium increased progressively during incubation, so that after 24 hours the total amount of hormone present in the tissue and medium was significantly greater than that in the tissue and medium prior to incubation (37.6 ± 9.6 ng/ml at 0 time vs 82.2 ± 7.7 ng/ml at 24 hours). When 3H-1-leucine (100 u Ci) was supplied during incubation, radioactive proteins were detected in the medium at 24 hr, 14–20% of which were specifically precipitated by antiserum to human pituitary prolactin. When aliquots of this medium were chromatographed on Sephadex G-100, 80–95% of the 3H-proteins precipitated by antiserum to pituitary prolactin eluted in the same position as did purified, iodinated pituitary prolactin. These data indicate that a species of prolactin which is identical to pituitary prolactin by the criteria of immunoprecipitation and gel chromatography is synthesized by human decidual tissue . 相似文献
15.
Kazuo Yoshida Michio Hagiya Naohiko Yanagishima 《Biochemical and biophysical research communications》1976,71(4):1085-1094
The substance responsible for the sexual agglutinability was successfully solubilized by a newly established autoclaving method from the surface of mating type cells of and purified by DEAE cellulose chromatography, gel filtration, affinity chromatography and electrophoresis. The substance was found to consist of at least two different glycoprotein subunits. The molecular weight of the substance was estimated to be about 23,000 daltons by gel filtration. The substance was univalent in its biological activity and specifically masked the sexual agglutinability of the mating type α cells. The substance formed a complementary complex with the agglutination substance from α cells in vitro. 相似文献
16.
Six heifers were used in a series of experiments to study the effects of experimental infection on bovine reproduction. Four three-year-old Zebu heifers were intravenously inoculated with T. vivax-strain Y58 — on days 14 and 16 of their estrous cycle and two control heifers in the same phase of estrus were not infected. All the heifers were bred in the research pens with a proven bull. The four infected heifers were bred at the first wave of parasitemia and the onset of pyrexia which characterised the infection. All the heifers were examined rectally 40 days after breeding. The four infected heifers were not pregnant but the two controls were. The infected heifers later became anestrous during the experimental period of more than five months. It is concluded that trypanosomiasis may contribute to high infertility rates in cattle kept in endemic areas. 相似文献
17.
Josie M. Nichols G.A.M. Cross 《Biochemical and biophysical research communications》1976,71(3):796-802
Kinetoplast DNA from the order Kinetoplastidae (trypanosomatids) exists as large associations (molecular weight 4 × 1010), made up of about 104 small, probably circular, molecules, commonly known as ‘minicircles’. These minicircles were originally thought to be identical in base composition, suggesting that the coding capacity of kinetoplast DNA is very restricted. However, linear molecules have also been observed in preparations of kinetoplast DNA, which, if they contain unique sequences, could represent additional genetic information. This linear DNA has been assumed to be derived from the kinetoplast, but the possibility of it being nuclear contamination has not been definitely ruled out. Work presented in this paper demonstrates that nuclear DNA contamination may indeed be present in kinetoplast DNA prepared by a commonly used method. 相似文献
18.
Robert C. Richmond John D. Zimbrick 《Biochemical and biophysical research communications》1975,64(1):391-398
Cells of C thy?321 are examined for thymine residue release from DNA following gamma-irradiation from 5 to 15 krad. Experimental conditions are designed to inhibit enzyme activity that might promote base residue release. Enzyme action is restricted in order to assess the physicochemical action of radiation on cellular DNA, and to this end irradiation is done under O2, N2, and N2O saturating conditions. Both thymine and thymidine release from bacterial DNA are detected and quantitated, and three oxygen effects are noted in comparing yields of these products. No difference in effect is observed between N2 and N2O gassing conditions, suggesting that the hydroxyl radical has little effect on thymine or thymidine release from irradiated DNA . 相似文献
19.
20.
A hepatotoxic dose of bromobenzene (3 mmoles/kg) decreases hepatic glutathione concentration in rats by approximately 80% within 5 hr following ip injection. A major bromobenzene metabolite, p-bromophenol at a similar dose did not significantly alter hepatic glutathione levels compared to controls. Twenty four hr after administration, serum glutamate pyruvate transaminase (SGPT) levels were significantly increased by bromobenzene but not by p-bromophenol. After 14C-bromobenzene administration, a significant amount of covalently bound radiolabel was detected in liver, kidney and small intestine. A small amount of covalently bound radiolabel was also detected in the lung. After a similar dose of 14C-bromophenol, covalently bound radiolabel was found in liver (62% of the amount detected with 14C-bromobenzene) and smaller amounts were detected in kidney, small intestine and lung. These data are consistent with the view that the hepatotoxity and glutathione depleting ability of bromobenzene are mediated mainly by bromobenzene-3, 4-oxide rather than by chemically reactive metabolites of p-bromophenol derived from bromobenzene. Covalently bound radiolabel from 14C-bromobenzene, however, may be derived from both bromobenzene-3, 4-oxide and the nontoxic reactive metabolites of p-bromophenol. 相似文献