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1.
Controlled alkaline hydrolysis of 16α-bromo-17-keto steroids 1, 5 and 7 with potassium carbonate and tetra-n-butylammonium hydroxide (n-Bu4NOH) and synthesis of 2α-hydroxy-3-ones 11, 13 and 16 by the controlled hydrolysis of the corresponding 2α-bromo-3-ones 9, 12 and 15 are described. Treatm carbonate in aqueous acetone or with n-Bu4NOH in aqueous dimethylformamide (DMF) gave 16α-hydroxy-17-ones 3, 6 and 8 in 85–90% yield, respectively. 2α-Hydroxy-3-ones 11, 13 and 16 were obtained by hydrolysis of the corresponding bromoketones 9, 12 and 15 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 9 and the 2β-bromo isomer 10 precedes the formation of the ketol 11 in which the true intermediate might be the 2β-isomer 10. However, rearranged androstane derivatives, 3β-hydroxy-2-ones 18 and 20, were stereoselectively obtained by treatment of the bromoketones 12 and 15 with an excess amount of sodium hydroxide.  相似文献   

2.
3.
History and ClinicalSigns: Herds infected with Trichomonasfetus have histories of infertility, occasional abortions, and pyometra.GrossLesions: 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.MicroscopicLesions: There are no specific microscopic lesions.CulturalProcedures: It is ordinarily not necessary to culture T.fetus in order to demonstrate its presence in placental fluids and/or abomasal contents.SerologicProcedures: There are no suitable seroligic procedures for diagnosing Trichomoniasis.SpecialProcedures: Wet mounts of abomasal contents and/or placental fluids are examined microscopically for T.fetus.PreferredDiagnosticProcedures: Demonstrate the presence of T.fetus by microscopic examination of wet mounts of placental fluids and/or abomasal contents.  相似文献   

4.
The replication defective transducing phage λplac5O29P3 carries a portion of the E.colilac operon in the b2 region of the lambda phage. This lac operon segment contains the lac promoter, the lac operator, and the β-galactosidase z gene, but does not contain the lac repressor i gene. The z gene can be expressed from both the inserted lac promoter and the phage promoter. When E.coli strain 594 (z?, i+) or JC6256 (Δlac) is infected by λplac5O29P3 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 λplac5O29P3 in the presence of additional cyclic AMP and IPTG, β-galactosidase synthesis is shown to be expressed from the inserted lac promoter.The ability to separate the phage promoter from the inserted lac promoter for β-galactosidase expression will simplify the interpretation whenever λplac5 is used.  相似文献   

5.
Two compounds were isolated from female Heliothisvirescens (Lepidoptera: Noctuidae) extracts and identified as cis-9-tetradecenal and cis-ll-hexadecenal. Together they elicit intense male H. virescnes response in laboratory tests and have attracted males in the field. Although cis-ll-hexadecenal is an H. zea sex pheromone, no evidence was obtained for cis-9-tetradecenal in H. zea.  相似文献   

6.
Molecular cloning vectors derived from the CoLE1 type plasmid pMB1.   总被引:4,自引:0,他引:4  
F Bolívar 《Life sciences》1979,25(10):807-817
Invitro recombination via restriction endonucleases and invivo 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 Eco RI, Bam HI, Bgl II, Dpn II, Hind III, Sal I, Xho I, Xam I, Taq I, Pst I, Hinc II, Pvu I, Sma I, Xma I, Bal I, Hpa I, Ava I, Pvu II, Hae III, Alu I, Hpa II, Eco RII and virtually any blunt-ended generated DNA fragment.  相似文献   

7.
Determination of the complete amino acid sequence of the rubredoxin isolated from the sulfate reducing bacterium Desulfovibriogigas 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 Desulfovibriovulgaris rubredoxin, 37 positions are identical, and with the sequences of Clostridiumpasteurianum, Peptostreptococcuselsdenii, Micrococcusaerogenes and D.vulgaris rubredoxins, 20 matching residues occur. A crystallographic study of the D.gigas rubredoxin is in progress.  相似文献   

8.
Transport of Pr3+ across phosphatidylcholine vesicles, monitored through 31P nmr, is first-order in monensin (1), second-order in etheromycin (2) or in lasalocid A (3). When 1 and 2 (or 2 and 3) are incorporated together in 1:1 ratio into the lipidic phase, transport is faster than with each ionophore alone. For instance, assuming that the complexes 2.Pr3+.2, 3.Pr3+.3, and 2.Pr3+3 are equiprobable, they effect transport at intrinsic relative rates of 1, 2, and 13.5, i.e. a remarkable synergism is set up.  相似文献   

9.
Cytochrome c1, the electron donor for cytochrome c, is a subunit of the mitochondrial cytochrome bc1 complex (complex III, cytochrome c reductase). To test if cytochrome c1 is the cytochrome c-binding subunit of the bc1 complex, binding of cytochrome c to the complex and to isolated cytochrome c1 was compared by a gel-filtration method under non-equilibrium conditions (a bc1 complex lacking the Rieske ironsulfur protein was used; von Jagow et al. (1977) Biochim. Biophys. Acta 462, 549–558). The approximate stoichiometries and binding affinities were found to be very similar. Binding of cytochrome c to isolated cytochrome b which is another subunit of the reductase was not detectable by the gel-filtration method. Further, the same lysine residues of cytochrome c were shielded towards chemical acetylation in the complexes c:c1 and c:bc1. From this we conclude that the same surface area of cytochrome c is in direct contact with cytochrome bc1 and with cytochrome c1 in the respective complexes and that therefore cytochrome c is most probably the structural ligand for cytochrome c in mitochondrial cytochrome c reductase.  相似文献   

10.
Coccidioidesimmits 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 C.immitis. There is, however, a difference in the laboratory susceptibility between the species studied (Antrozouspallidus and Macrotuscalifornicus). Antrozouspallidus requires 8 times more arthrospores (400 as compared to 50) than does Macrotuscalifornicus to produce a defineable infection. Our cultures for C.immitis in the tissue of Antrozous produced colonies of the bacterium Serratiamarcescens. 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 C. immitis found in the laboratory population of Antrozous. 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 Neotoma and Bassariscus rarely in these tunnels) may have tracked the fungus into these deep tunnel sites.  相似文献   

11.
The syntheses of (±) 2α,6β-diethyl-7α-ethynyl-3α-(p-hydroxyphenyl)-trans-bicyclo[4.3.0]nonan-7β-ol (8), (±)2β,6β-diethyl-7α-ethynyl-3β-(p-methoxyphenyl)-trans-bicyclo[4.3.0]nonan-7β-ol (12) and (±) 2α,6β-diethyl-7α-ethynyl-3β-(p-hydroxyphenyl)-trans-bicyclo[4.3.0]nonan-7β-ol (18) and their derivatives, which are essentially B-seco-steroids having cis-anti-trans, cis-syn-trans and trans-anti-trans geometries have been carried out. A study of their antiimplantation activities (AI) and receptor binding affinities (RBA) show that trans-anti-trans compounds are biologically most potent, followed by the corresponding cis-anti-trans and cis-syn-trans compounds. The most potent compound 18 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 +cr and crcr mice and by growing the recombined skins in the testes of histocompatible mice. Since crcr 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 +crepidermis-+cr dermis and +crepidermis-crcr dermis grew hair, whereas grafts of the combinations crcrepidermis-+cr dermis and crcrepidermis-crcr 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.
We wish to report here the syntheses of (5S, 6R)-5-hydroxy-, (5R, 6R)-5-hydroxy-, (5R, 6S)-5-hydroxy-, and (5S, 6S)-5-hydroxy-PGI1 and their methyl ester derivatives. Treatment of (5R, 6S)-5-epoxy- and (5S, 6R)-5-epoxy-PFG methyl esters with acid washed silica gel afforded (5R, 6R)-5-hydroxy- and (5S, 6S)-5-hydroxy-PGI1 methyl esters; correspondingly, silica promoted cyclization of (5S, 6S)-epoxy- and (5S, 6R)-5-epoxy- PGF1 methyl esters yielded (5S, 6R)-5-hydroxy- and (5R, 6S)-5-hydroxy- PGI1 methyl esters. Alternatively, the 5-hydroxyl group was introduced into the PGI1 skeleton via 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.
The enantiomer selection in the nucleophilic addition reaction of optically active amines such as α-amino acid esters to phenylalanine and N-methylphenylalanine N-carboxyanhydride in m-dimethoxybenzene as a solvent has been investigated. Stereoselectivity between the amines and the N-carboxyanhydrides 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 N-carboxyanhydride the growing chain end reacts preferentially with one of the enantiomorphic N-carboxyanhydrides having the same configuration, and indicates the importance of the investigation of stereoselectivity in the N-carboxyanhydride polymerization using suitable model reactions. Most (S)-α-amino acid esters reacted preferentially with (R)-phenylalanine N-carboxyanhydride, and this type of stereoselectivity increased with the N-methylation of N-carboxyanhydride 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 N-carboxyanhydrides was explained satisfactorily in terms of the transition state model in which the interaction of N-carboxyanhydride nitrogen and α-amino acid ester carbonyl as well as the interaction of N-carboxyanhydride carbonyl and α-amino acid ester nitrogen was taken into account. (S)-Proline ethyl ester did not show enantiomer selectivity toward phenylalanine N-carboxyanhydride, but reacted preferentially with (S)-(N)-methylphenylalanine N-carboxyanhydride. for the reaction of proline ester with N-carboxyanhydride 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 N-carboxyanhydride hitherto reported are discussed.  相似文献   

15.
A novel synthesis of 16α-hydroxy-4-androstene-3,17-dione (3), 16α-hydroxy-4-androstene-3, 6,17-trione (4), 17β-amino-5-androsten-3β-ol (10) and 17β-amino-4-androsten-3-one (14) is described. 16α-Bromoacetoxy-4-androstene-3, 17-dione (5), 16α-bromoacetoxy-4-androstene-3, 6,17-trione (6) and 17β-bromoacetylamino-4-androsten-3-one (15) were synthesized as potentially selective irreversible inhibitors of androgen aromatases. 16α-Bromo-4-androstene-3,17-dione (1) and 16α-bromo-4-androstene-3, 6,17-trione (2) were converted to compounds 3 and 4 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 (11) using ammonium acetate and sodium cyanohydridoborate (NaBH3CN) and a subsequent treatment with acid gave the amines 10 and 14 respectively, as a salt. The corresponding 17-imino compounds 9 and 13 were also isolated from the reaction mixtures when methanol was used as a solvent for the reaction. The 16α-hydroxyl compounds 3 and 4 and the 17β-amino compound 14 were con- verted to the corresponding bromoacetyl derivatives, 5, 6, and 15, 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 CaP, MgP, KP and (Ca + Mg + K)P 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 CaP ratio and increased the MgP ratio of the granules. The mean KP ratio and (Ca + Mg)P ratio were not significantly altered. When medium M was supplemented with 0.3 mM calcium, there was no significant change in the CaP, MgP, KP nor (Ca + Mg)P ratios. When supplemented with 3 mM Ca, the CaP ratio increased slightly, and the MgP ratio decreased slightly. There was no significant change in the KP and (Ca + Mg)P ratio. When each medium was supplemented with strontium, all granules incorporated this element, probably at the expense of calcium. The (Ca + Mg + Sr)P ratios in granules in each strontium-containing medium were comparable to the (Ca + Mg)P 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 (Bosindicus). The reproductive endocrinology of Bosindicus cattle differs from that of Bostaurus breeds; the estrus is shorter and less intense and occurs late in relation to an estrogen stimulus. Moreover, the Bosindicus 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 Bosindicus females. Furthermore, they have fewer preovulatory LH surges than Bostaurus 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 Bosindicus 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.
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. Corynebacteriumpyogenes and Fusobacteriumnecrophorum 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 C.pyogenes, two were infected only with F.necrophorum, and seven were infected with both organisms. All five of the cows which were infected with either C.pyogenes or F.necrophorum 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 C.pyogenes. 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 C.pyogenes or F.necrophorum 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 C.pyogenes and F.necrophorum 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 (Agelaius phoeniceus) and albino rats were incubated with N,N-dimethylaniline (DMA)_in complete incubation mixtures at pH 7.9 and 37°C for 10 min. Formaldehyde and N,N-dimethylaniline-N-oxide produced from DMA were measured. Redwings were found to have significantly lower N-demethylation activities than rats, and redwings had only marginal or no N-oxidation activities. Hepatic microsomes from redwings did not further metabolize the N-oxide. The N-oxidation and N-demethylation activities of brown-headed cowbirds (Molothrus ater), common grackles (Quiscalus quiscula), and starlings (Sturnus vulgaris) were similar to those of redwings.  相似文献   

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