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1.
Controlled alkaline hydrolysis of 16α-bromo-17-keto steroids , and with potassium carbonate and tetra-n-butylammonium hydroxide (n-Bu4NOH) and synthesis of 2α-hydroxy-3-ones , and by the controlled hydrolysis of the corresponding 2α-bromo-3-ones , and are described. Treatm carbonate in aqueous acetone or with n-Bu4NOH in aqueous dimethylformamide (DMF) gave 16α-hydroxy-17-ones , and in 85–90% yield, respectively. 2α-Hydroxy-3-ones , and were obtained by hydrolysis of the corresponding bromoketones , and in high yields using the above conditions or sodium hydroxide in pyridine or DMF, respectively. Deuterium labeling experiments suggested that equilibration between the 2α-bromoketone and the 2β-bromo isomer precedes the formation of the ketol in which the true intermediate might be the 2β-isomer . However, rearranged androstane derivatives, 3β-hydroxy-2-ones and , were stereoselectively obtained by treatment of the bromoketones and with an excess amount of sodium hydroxide. 相似文献
2.
Fine structure of the recB and recC gene region of Escherichia coli 总被引:14,自引:0,他引:14
M Sasaki T Fujiyoshi K Shimada Y Takagi 《Biochemical and biophysical research communications》1982,109(2):414-422
3.
John W. Kendrick 《Theriogenology》1976,5(3):150-152
and : Herds infected with have histories of infertility, occasional abortions, and pyometra.: There are no specific gross lesions in the fetus. The fetuses are usually aborted in the first half of gestation and may or may not be accompanied by the placenta.: There are no specific microscopic lesions.: It is ordinarily not necessary to culture in order to demonstrate its presence in placental fluids and/or abomasal contents.: There are no suitable seroligic procedures for diagnosing Trichomoniasis.: Wet mounts of abomasal contents and/or placental fluids are examined microscopically for .: Demonstrate the presence of by microscopic examination of wet mounts of placental fluids and/or abomasal contents. 相似文献
4.
The replication defective transducing phage λp3 carries a portion of the operon in the 2 region of the lambda phage. This operon segment contains the promoter, the operator, and the β-galactosidase gene, but does not contain the repressor gene. The gene can be expressed from both the inserted promoter and the phage promoter. When strain 594 (?, +) or JC6256 (Δ) is infected by λp3 in the absence of additional cyclic AMP, β-galactosidase synthesis is shown to be expressed from the phage promoter. When 594 (λ+) or JC6256 (λ+) is infected by λp3 in the presence of additional cyclic AMP and IPTG, β-galactosidase synthesis is shown to be expressed from the inserted promoter.The ability to separate the phage promoter from the inserted promoter for β-galactosidase expression will simplify the interpretation whenever λp5 is used. 相似文献
5.
Two compounds were isolated from female (Lepidoptera: Noctuidae) extracts and identified as -9-tetradecenal and -ll-hexadecenal. Together they elicit intense male . response in laboratory tests and have attracted males in the field. Although -ll-hexadecenal is an . sex pheromone, no evidence was obtained for -9-tetradecenal in . . 相似文献
6.
F Bolívar 《Life sciences》1979,25(10):807-817
recombination via restriction endonucleases and genetic translocation of an impicillin resistance gene, have been utilized for the construction of a series of cloning vehicles. These vectors have been derived by combining the essential replication properties of plasmid pMBl, a CoLEl type plasmid, with one, two or three resistance markers (tetracycline, ampicillin, chloramphenicol and colicin El production). During the construction of these vectors, the position of restriction sites used for cloning DNA fragments, relative to the antibiotic resistance genes and the origin of DNA replication, have been determined. The use of the cloning vectors pMB9, pBR313, pBR322, pBR324, pBR325 permits the molecular cloning and easy selection of RI, HI, II, II, III, I, I, I, I, I, II, I, I, I, l I, I, I, II, III, I, II, RII and virtually any blunt-ended generated DNA fragment. 相似文献
7.
C H Letendre P C MacDonnell G Guroff 《Biochemical and biophysical research communications》1976,76(2):615-617
Determination of the complete amino acid sequence of the rubredoxin isolated from the sulfate reducing bacterium showed that the molecule consists of a single polypeptide chain of 52 residues. The sequence of the first 42 residues was determined using an automatic Protein Sequencer. Peptides derived from tryptic hydrolysis and from specific cleavage at tryptophan residue were used to construct the total sequence. Compared with the sequence of rubredoxin, 37 positions are identical, and with the sequences of , , and rubredoxins, 20 matching residues occur. A crystallographic study of the rubredoxin is in progress. 相似文献
8.
Jean Grandjean Pierre Laszlo 《Biochemical and biophysical research communications》1982,104(4):1293-1297
Transport of Pr3+ across phosphatidylcholine vesicles, monitored through 31P nmr, is first-order in monensin (), second-order in etheromycin () or in lasalocid A (). When and (or and ) are incorporated in 1:1 ratio into the lipidic phase, transport is faster than with each ionophore alone. For instance, assuming that the complexes .Pr3+., .Pr3+., and .Pr3+ are equiprobable, they effect transport at intrinsic relative rates of 1, 2, and 13.5, a remarkable synergism is set up. 相似文献
9.
H.R. Bosshard M. Zürrer H. Schägger G. von Jagow 《Biochemical and biophysical research communications》1979,89(1):250-258
Cytochrome 1, the electron donor for cytochrome , is a subunit of the mitochondrial cytochrome 1 complex (complex III, cytochrome reductase). To test if cytochrome 1 is the cytochrome -binding subunit of the 1 complex, binding of cytochrome to the complex and to isolated cytochrome 1 was compared by a gel-filtration method under non-equilibrium conditions (a 1 complex lacking the Rieske ironsulfur protein was used; von Jagow et al. (1977) Biochim. Biophys. Acta , 549–558). The approximate stoichiometries and binding affinities were found to be very similar. Binding of cytochrome to isolated cytochrome which is another subunit of the reductase was not detectable by the gel-filtration method. Further, the same lysine residues of cytochrome were shielded towards chemical acetylation in the complexes 1 and 1. From this we conclude that the same surface area of cytochrome is in direct contact with cytochrome 1 and with cytochrome 1 in the respective complexes and that therefore cytochrome is most probably the structural ligand for cytochrome in mitochondrial cytochrome reductase. 相似文献
10.
Isolation of coccidioides immitis from bat guano and preliminary findings on laboratory infectivity of bats with Coccidioides immitis 总被引:1,自引:0,他引:1
has been isolated from the guano of bats obtained beneath bat roosting places deep within deserted mine tunnels. Certain species of bats have been demonstrated to be susceptible to experimental infection by . There is, however, a difference in the laboratory susceptibility between the species studied ( and ). requires 8 times more arthrospores (400 as compared to 50) than does to produce a defineable infection. Our cultures for in the tissue of produced colonies of the bacterium . Because these tissues were handled under sterile conditions the presence of this red pigment (prodigiosin) producing bacterium was thought not the result of contamination. Prodigiosin suggests a possible mechanism for the apparent greatly reduced susceptibility to . found in the laboratory population of . Skin and serological tests on bats were negative as were cultures of guano from experimentally infected bats and mice. It is speculated that infected dying bats that fall to the floor beneath their roosting sites may contaminate the guano. We of course realize that other animals (we have found and rarely in these tunnels) may have tracked the fungus into these deep tunnel sites. 相似文献
11.
Akhil G. Jhingran R.C. Gupta Suprabhat Ray A.K. Agarwal M.M. Singh Nitya Anand 《Steroids》1983,42(6):627-634
The syntheses of (±) 2α,6β-diethyl-7α-ethynyl-3α-(-hydroxyphenyl)--bicyclo[4.3.0]nonan-7β-ol (), (±)2β,6β-diethyl-7α-ethynyl-3β-(-methoxyphenyl)--bicyclo[4.3.0]nonan-7β-ol () and (±) 2α,6β-diethyl-7α-ethynyl-3β-(-hydroxyphenyl)--bicyclo[4.3.0]nonan-7β-ol () and their derivatives, which are essentially B-seco-steroids having and geometries have been carried out. A study of their antiimplantation activities (AI) and receptor binding affinities (RBA) show that compounds are biologically most potent, followed by the corresponding and compounds. The most potent compound is active at 1 mg/kg in rats. Introduction of 7α-ethynyl group increases their AI activity; however, no significant effect on their RBA is observed. 相似文献
12.
The site of action of the crinkled (cr) locus was determined by combining dermis and epidermis from the tail of 15-day and mice and by growing the recombined skins in the testes of histocompatible mice. Since mice have bald tails, the presence or absence of hair in the graft was the feature used to determine gene action. Grafts of the combinations dermis and dermis grew hair, whereas grafts of the combinations dermis and dermis produced no hair. It was concluded that the cr locus, at least for tail skin, is active in the epidermis. 相似文献
13.
John C. Sih Roy A. Johnson Eldon G. Nidy David R. Graber 《Prostaglandins & other lipid mediators》1978,15(3):409-421
We wish to report here the syntheses of (5, 6)-5-hydroxy-, (5, 6)-5-hydroxy-, (5, 6)-5-hydroxy-, and (5, 6)-5-hydroxy-PGI1 and their methyl ester derivatives. Treatment of (5, 6)-5-epoxy- and (5, 6)-5-epoxy-PFG1α methyl esters with acid washed silica gel afforded (5, 6)-5-hydroxy- and (5, 6)-5-hydroxy-PGI1 methyl esters; correspondingly, silica promoted cyclization of (5, 6)-epoxy- and (5, 6)-5-epoxy- PGF1 methyl esters yielded (5, 6)-5-hydroxy- and (5, 6)-5-hydroxy- PGI1 methyl esters. Alternatively, the 5-hydroxyl group was introduced into the PGI1 skeleton reaction of the 5-mercuric halides with sodium borohydride in the presence of oxygen. Stereochemical assignments were based on their mode of synthesis and 1H nmr shift differences. 相似文献
14.
Yukio Imanishi Hiroyuki Ohnishi Yutaka Hashimoto 《International journal of biological macromolecules》1981,3(2):97-104
The enantiomer selection in the nucleophilic addition reaction of optically active amines such as α-amino acid esters to phenylalanine and in as a solvent has been investigated. Stereoselectivity between the amines and the was found to change markedly according to the reaction conditions. This experimental finding is in contrast to the idea hitherto accepted that in the nucleophilic addition-type polymerization of α-amino acid the growing chain end reacts preferentially with one of the enantiomorphic having the same configuration, and indicates the importance of the investigation of stereoselectivity in the polymerization using suitable model reactions. Most acid esters reacted preferentially with , and this type of stereoselectivity increased with the of and with increasing bulkiness of the Cα substituent of α-amino acid esters (alanine < norleucine < leucine < valine). The relationship observed between the stereoselectivity and the structures of amines and was explained satisfactorily in terms of the transition state model in which the interaction of nitrogen and α-amino acid ester carbonyl as well as the interaction of carbonyl and α-amino acid ester nitrogen was taken into account. ethyl ester did not show enantiomer selectivity toward phenylalanine , but reacted preferentially with . for the reaction of proline ester with a transition-state model was proposed, which was different from the transition state model proposed for other α-amino acid esters. Some experiments were carried out to examine the transition-state models proposed. The implications of the present investigation in stereoselectivity in the nucleophilic addition-type polymerization of hitherto reported are discussed. 相似文献
15.
A novel synthesis of 16α-hydroxy-4-androstene-3,17-dione (), 16α-hydroxy-4-androstene-3, 6,17-trione (), 17β-amino-5-androsten-3β-ol () and 17β-amino-4-androsten-3-one (14) is described. 16α-Bromoacetoxy-4-androstene-3, 17-dione (), 16α-bromoacetoxy-4-androstene-3, 6,17-trione () and 17β-bromoacetylamino-4-androsten-3-one () were synthesized as potentially selective irreversible inhibitors of androgen aromatases. 16α-Bromo-4-androstene-3,17-dione () and 16α-bromo-4-androstene-3, 6,17-trione () were converted to compounds and in 80–90% yield by controlled stereospecific hydrolysis using sodium hydroxide in aqueous pyridine. Reductive amination of 3β-hydroxy-5-androsten-17-one and 3-methoxy-3,5-androstadien-17-one () using ammonium acetate and sodium cyanohydridoborate (NaBH3CN) and a subsequent treatment with acid gave the amines and respectively, as a salt. The corresponding 17-imino compounds and were also isolated from the reaction mixtures when methanol was used as a solvent for the reaction. The 16α-hydroxyl compounds and and the 17β-amino compound were con- verted to the corresponding bromoacetyl derivatives, , , and , with bromoacetic acid and N,N'-dicyclohexylcarbodiimide. 相似文献
16.
17.
Quantitative electron probe analysis was employed to analyse refractile granules of T. pyriformis individually and in situ. The mean ratios of , , and in granules were similar in cells grown in three different nutrient media. Supplementing the calcium content of proteose-peptone medium with 0.3 and 3 mM calcium depressed the mean ratio and increased the ratio of the granules. The mean ratio and ratio were not significantly altered. When medium M was supplemented with 0.3 mM calcium, there was no significant change in the , , nor ratios. When supplemented with 3 mM Ca, the ratio increased slightly, and the ratio decreased slightly. There was no significant change in the and ratio. When each medium was supplemented with strontium, all granules incorporated this element, probably at the expense of calcium. The ratios in granules in each strontium-containing medium were comparable to the ratio in the granules in strontium-free media, indicating that the mix of divalent ions in granules may vary, but the proportion of divalent ions to phosphorus tends to be uniform. 相似文献
18.
R.D. Randel 《Theriogenology》1984,21(1):170-185
Reproductive function is mediated by season in the Indian breeds of cattle (). The reproductive endocrinology of cattle differs from that of breeds; the estrus is shorter and less intense and occurs late in relation to an estrogen stimulus. Moreover, the female has a smaller preovulatory surge of luteinizing hormone (LH), which occurs earlier relative to the onset of estrus, and she ovulates sooner after the onset of estrus. The corpus luteum is smaller and contains less progesterone, and the serum progesterone concentration is lower in females. Furthermore, they have fewer preovulatory LH surges than females and their luteal cells are less responsive to LH in vitro during the winter. Their fertility is lower during the late fall and winter months. For cattle, recovery of transferable embryos and survival of embryos in the recipient are at their maximum from July through October. 相似文献
19.
C.A. Ruder R.G. Sasser R.J. Williams J.K. Ely R.C. Bull J.E. Butler 《Theriogenology》1981,15(6):573-580
Clinical conditions, which were observed in primiparous Angus and Hereford heifers with postpartum uterine infections are reported. Forty-three of sixty-four cows (67%) had uterine infections. and were the most frequently isolated aerobe and anaerobe, respectively. Twelve of the sixty-four cows (18.8%) had infections that involved these species. Three of these twelve cows were infected only with , two were infected only with , and seven were infected with both organisms. All five of the cows which were infected with either or showed signs of estrus and four of the five cows conceived by 110 days postpartum. The single cow that did not conceive was infected with . Three of the seven cows which were infected with both organisms showed signs of estrus and none of the seven cows conceived by 110 days postpartum. In addition, when only or was isolated from the uterus, cows had either mild or no clinical signs of infection. In contrast, the seven cows which were infected with both organisms had severe clinical signs of infection that included excessive vulvar discharge, uterine abscesses and pelvic adhesions. These observations suggested that a pathogenic synergism between and might have caused the increased severity of postpartum uterine infections, and the subsequent detrimental effect on return to estrus and conception. 相似文献
20.
Hepatic microsomes prepared from red-winged blackbirds () and albino rats were incubated with ,-dimethylaniline (DMA)_in complete incubation mixtures at pH 7.9 and 37°C for 10 min. Formaldehyde and ,-dimethylaniline--oxide produced from DMA were measured. Redwings were found to have significantly lower -demethylation activities than rats, and redwings had only marginal or no -oxidation activities. Hepatic microsomes from redwings did not further metabolize the -oxide. The -oxidation and -demethylation activities of brown-headed cowbirds (), common grackles (), and starlings () were similar to those of redwings. 相似文献