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1.
The synthesis and characterization of E- and Z-3,4-bis(4-hydroxyphenyl)-2-hexene (E- and Z-pseudo-DES) and of Z-3,4-bis(4-hydroxyphenyl)-2-hexen-1-ol (Z-1-hydroxypseudo-DES) are described. These compounds are useful as probes in the study of hormone action.  相似文献   

2.
The transducing phage λdarg14, carrying a portion of the E. coli chromosome including argECBH, is derived from the heat-inducible, lysis-defective strain λy199, which has the b519 and b515 deletions. Cleavage of λy199 DNA by EcoRI 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 b519 minus b515, the cleavage site between A and B being eliminated). Cleavage of λdarg14 DNA by EcoRI 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 E. coli argECBH cluster is on the 14-1 segment.  相似文献   

3.
Isozyme patterns of S-adenosylmethionine synthetase have been measured with and without dimethylsulfoxide in rat liver incuced by ethionine. The activity of the α-form is increased following administration of ethionine plus adenine for 2 consecutive days, and gradually decreased to control level on the 7th day after treatment, whereas the activity of β-form is relatively unaffected. Methyl-deficient transfer RNA and enhanced levels of transfer RNA-methylating enzymes were found in the livers of female rats after the treatment for 2 days, following which they gradually returned to control level.  相似文献   

4.
OKY-1581 is an effective inhibitor of thromboxane synthesis invivo and invitro. 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 invivo or invitro 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   

5.
Biochemical and electrophysiological studies were conducted on the electric organ of the electric fish of the Nile, Malapteruruselectricus, in order to determine if transmission was chemically mediated. There was no binding of [3H] acetylcholine, [3H] quinuclidinyl benzilate or [3H]-perhydrohistrionicotoxin; but low acetylcholinesterase activity was observed, as was binding of [125I] α-bungarotoxin. The latter binding was detectable at 0.85 ± 0.07 pmol/g tissue, and was totally inhibited by 1 μM α-bungarotoxin or 100 μM d-tubocurarine. A tetrodotoxin-sensitive action potential was measured which was Na+- dependent. Depolarization (30–40 mV) was caused by carbamylcholine, and this was blocked by d-tubocurarine or α-bungarotoxin. The data suggest that this electric organ which may be a rich source for electrically excitable channels, is innervated by nicotonic cholinergic motoneurons, but the concentrations of acetylcholine receptors and acetylcholinesterase are very low.  相似文献   

6.
An inhibitor of Streptococcus,mutans endodextranase was detected in proteins prepared from batch cultures of S.,mutans strains representing serotypes a through g. 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 S.,mutans known to produce this enzyme.  相似文献   

7.
A new glutathione S-transferase has been purified to homogeneity from 105,000 × g supernatant of Sprague-Dawley rat liver homogenates. The purified enzyme exhibited specific activities of approximately 1.8, and 0.12 μmoles. min?1. mg?1 toward 1-chloro 2,4-dinitrobenzene and cumene hydroperoxide respectively. The SDS gel electrophoresis data on subunit composition revealed that the new transferase is composed of two subunits with an identical Mr of 24,400 (Yα Family). Our invitro translation experiments with rat liver poly(A) RNAs and substrate specificity data suggest that this subunit is different from the previously reported Ya, Yb and Yc subunits of rat liver glutathione S-transferases. Comparatively, the new isozyme showed significant activity toward 1,2 epoxy-3-(P-nitrophenoxy)-propane, ethacrynic acid and P-nitrophenyl acetate, 0.4, 0.34 and 0.18 μ moles. min?1. mg?1 respectively.  相似文献   

8.
Rhodotorucine A which induces mating tube formation of a cells in Rhodosporidiumtoruloides is metabolized rapidly by a cells. By use of labeled rhodotorucine A, 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 a cells at log phase did not metabolize rhodotorucine A.  相似文献   

9.
The specific synthesis of argF mRNA directed by the argF gene carried on the specialized transducing bacteriophage λh80C1857dargF, performed in vitro, is described with the use of an S180 extract from a strain carrying argR?. Synthesis of argF mRNA is biphasic at approximately 7 minutes. The regulation of argF mRNA synthesis by the specific arginine holorepressor present in an S180 extract prepared from a strain carrying the argR+ allele is described.  相似文献   

10.
Uterine stage embryos collected from the hamster (8-cell) and cow (morula, early blastocyst) were monitored for development invitro (embryo culture) and invivo (embryo transfer) following premature removal of the zona pellucida.Removal of the zona pellucida did not significantly affect invitro 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 inutero. Such fusion was observed to occur invitro 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 invitro and invivo 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   

11.
The paromomycin producing organism Streptomycesrimosusforma paromomycinus is resistant to this antibiotic and contains a phosphotransferase which inactivates paromomycin. The gene encoding this enzyme has been inserted in the Streptomyces vector pIJ702 and then cloned in Streptomyceslividans, 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 Streptomyces cloning vectors with the versatility of insertional inactivation.  相似文献   

12.
The activities of the main enzymes involved in fatty acid utilization i.e. palmitoyl CoA synthetase as well as peroxisomal and mitochondrial β-oxidation were measured in brown adipose tissue homogenates of lean and ob/ob mice kept at 23°C or acclimated at 4°C. The proton conductance pathway, i.e. the number of purine nucleotide (GDP) binding sites and the percentage of 32,000 polypeptide in brown adipose tissue mitochondria were also measured. In the ifob/ob mice at 23° C, the specific activities of the palmitoyl CoA synthetase and of the β-oxidation as well as the number of GDB binding sites were lower than in the lean mice by 26%, 43% and 37%, respectively. The percentage of 32, 000 polypeptide, however, was the same in both groups. In the ob/ob mice at 23° C, the lower homogenate β-oxidation specific activity was due to the fact that the peroxisomal and mitochondrial specific activities were 44% and 37% lower, respectively. Cold acclimation at 4° C was found to cause an increase of the palmitoyl CoA synthetase specific activity, of the palmitoyl CoA synthetase and peroxisomal β-oxidation total activities and of the number of GDP binding sites, in both lean and ob/ob mice. Cold acclimation increased the percentage of 32,000 polypeptide in the ob/ob mice only.  相似文献   

13.
This case report addresses the occurrence of Brucellosis and its effect on the cattle in developing countries. Three Zebu bulls (Bosindicus) 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. B. abortus 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   

14.
Rat liver parenchymal cells (hepatocytes) were isolated by a collagenase perfusion technique and maintained as monolayers in serum-free medium in collagen-coated culture dishes. Glucagon, in combination with dexamethasone, induced α-aminoisobutyric acid transport in these cells. Addition of purified Clostridiumperfringens enterotoxin to hepatocytes preinduced by glucagon and dexamethasone rapidly depressed (but did not abolish) α-aminoisobutyric acid transport. The toxin effect was dose dependent: 1000 or 300 ng/ml produced maximal depression whereas 100 or 40 ng/ml were without effect in 120 minutes. The effect was eliminated by pretreating the toxin with heat or specific antisera. The effect of enterotoxin on α-aminoisobutyric acid transport in two cultured rat hepatoma cell lines (H4-II-E-C3 and McA-RH 7777) was also investigated. Only the McA-RH 7777 cells were sensitive to the toxin suggesting that the enterotoxin may interact with specific membrane components of normal rat liver cells which are also present on some (but not all) cancerous rat liver cells.  相似文献   

15.
Both pairs of dl-ll-desoxy- and dl-13-cis-erythro-15, 16-dihydroxyprostaglandins have been synthesized via 1,4-conjugate additions of an appropriately functionalized cis-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   

16.
In an attempt to isolate and to study the electron transport system of Azotobacter vinelandii, we have isolated and purified a membrane-bound cytochrome o. The cytochrome o, purified as a detergent (Triton X-100) and hemoprotein complex, contained 1.6 nmoles heme per mg of protein. Cold-temperature spectrum showed that no other cytochrome was associated with the purified preparation, and electrophoresis revealed that only one type of hemoprotein was obtained. The purified cytochrome o reacted with both carbon monoxide and cyanide readily. Only in the reduced form did it combine with carbon monoxide, whereas the oxidized form reacted with cyanide. An “oxygenated” form of the cytochrome o was demonstrated to be spectrally distinguishable from both the oxidized and the reduced forms.  相似文献   

17.
Prostaglandin (PG) levels in follicular fluid from preovulatory follicles of rabbit ovaries perfused invitro were measured in order to compare PG changes in this model system with those that occur invivo and in isolated, LH-treated follicles inbarvitro. One ovary from each rabbit was perfused without further treatment (control). The other ovary was exposed to LH (0.1 or 1 ug/ml) beginning 1 hour (h) after initiation of perfusion. Samples of perfusion medium were taken at frequent intervals for measurement of PGE, PGF, progesterone and estradiol 17β. The perfusions were terminated when the first ovulation occurred or appeared imminent as judged by changes in the size and shape of the follicles. Follicular fluid was then rapidly aspirated from all large follicles on both ovaries for PGE and PGF measurement.Ovulations occurred only in the LH-treated ovaries. Progesterone and estradiol levels were significantly elevated in the perfusion medium within 1 h of LH treatment in comparison to controls. PG levels in perfusion medium from the control and LH-treated ovaries were not different throughout perfusion and increased in both groups. In contrast, PG levels measured in follicular fluid from LH-treated ovaries were 4- to 5-fold greater than in fluid from control ovaries. It is concluded that ovulation induced by LH in this experimental model is accompanied by an increase in follicular PG levels similar to that seen in other invivo and invitro models. This difference in follicular PG levels between the LH-treated and control ovaries is, however, not reflected in the perfusion medium.  相似文献   

18.
Normal estrous cycles were established for twenty beef heifers. Ten heifers were inoculated with blood from a known Anaplasmamarginale carrier. The inoculated heifers experienced anemia, anorexia, and positive Anaplasmamarginale complement-fixing antibody titers, and A. marginale was observed on the erythrocytes while uninoculated control heifers remained normal. Further observation following inoculation revealed that five of ten inoculated heifers experienced anestrus while controls continued to cycle normally. Anestrus coincided with clinical signs of acute anaplasmosis. Normal estrus patterns returned following treatment and recovery. This study provides evidence that acute anaplasmosis in beef heifers may cause anestrus and therefore lead to reproductive inefficiency.  相似文献   

19.
Aspirin and salicylate are well-known but poorly understood teratogens in laboratory animals. Because aspirin inhibits PG synthesis, we systematically examined PG synthesis in rat embryo homogenates, the inhibition of PG synthesis in vivo and ex vivo by various non-steroidal anti-inflammatory drugs, and tested the hypothesis that the inhibition of PG synthesis is responsible for aspirin-induced limb defects in rats. We report that embryonic rat homogenates synthesis 6-keto-PGF, PGE, and PGF in large amounts from endogenous substrate, that aspirin and other non-steroidal anti-inflammatory drugs inhibit PG synthesis in vitro but not necessarily in vivo, and that contrary to our original hypothesis, the inhibition of PG synthesis is likely not responsible for aspirin-induced limb defects in rats.  相似文献   

20.
The synthesis of d1-4,5,6-trinor-3,7-inter-m-phenylene-3-oxaprostaglandins oxaprostaglandins of the E1 and F1α series7 from 6-endo-(1-heptenyl)-bicyclo[3:1:0]hexan-3-one (III), is described. Preliminary biological screening data for gerbil colon smooth muscle stimulation, rat blood pressure and substrate specificity toward 15-hydroxyprostaglandin dehydrogenase is presented. Platelet function studies, both in vitro and in vivo of d1-4,5,6-trinor-3,7-inter-m-phenylene-3-oxa-PGE1, methyl ester (VIII) are presented.  相似文献   

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