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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   

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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   

5.
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   

6.
Muscular dysgenesis (mdg) in the mouse is a recessive autosomal mutation affecting the striated musculature: during the whole gestation period, the muscles never show any sign of contractile activity. They are cytologically immature at birth, although the diaphragm is more mature than limb muscles, as confirmed by the levels of creatine phosphokinase. In both limb muscles and diaphragm the cytochemical localization of acetylcholinesterase demonstrates focal accumulations on the entire surface of mdgmdg muscles, whereas such foci of acetylcholinesterase activity are restricted to a narrow end plate-rich region in +mdg? diaphragms. Teased single mdgmdg myofiber preparations show that one myofiber can possess several foci of acetylcholinesterase, generally presenting aspects of very immature motor end plates. A study of the motor innervation, after silver nitrate impregnation, provides evidence for a spectacular overgrowth and a generalized sprouting of mdgmdg nerves and axons. The mdgmdg nerve terminals are generally very immature-looking, with an intense ultraterminal sprouting. Aspects suggesting a denser multiple innervation of mdgmdg than +mdg? myofibers have been observed and choline acetyltransferase activity is increased in mdgmdg tissues. Acetylcholinesterase specific activity and the number of α-bungarotoxin binding sites per milligram protein increased in mdgmdg compared to +mdg? diaphragms. The very low amount of 16 S (and 12 S) acetylcholinesterase is probably related to mdgmdg muscle inactivity. If the cytological and biochemical data are compared, it seems possible to propose that mdgmdg myofibers and axons are in contact in several regions of the same myofiber, in variably mature appositions, and with a very dense multi-innervation.  相似文献   

7.
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   

8.
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   

9.
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   

10.
Carnosine (β-alanyl-L-histidine) activates rabbit muscle phosphorylase a in the presence and absence of AMP and phosphorylase b in the presence of AMP in a biphasic manner with a maximal activation at about 50mM carnosine and with phosphorylase b showing a greater degree of activation than phosphorylase a. Anserine (β-alanyl-L-Nπ-methyl-histidine) activates phosphorylase a to a lesser extent than carnosine up to a concentration of 90mM, whereas with phosphorylase b a weak activation below 30mM and a concentration-dependent inhibition above this concentration occurs. These effects are specific for the dipeptides and are not shown by their constituent amino acids. Carnosine and anserine activate phosphorylase a in the presence of the allosteric inhibitors ATP, D-glucose and caffeine, and the inhibition of phosphorylase b by anserine is also observed in the presence of these inhibitors.  相似文献   

11.
When murine sarcoma virus-transformed cells are labeled with [3H]lysine invivo for various periods, 5 of 6 isoaccepting lysine tRNAs separable by RPC-5 chromatography are aminoacylated in 1 hr to the same extent that they are aminoacylated invitro. The sixth isoacceptor, tRNA6Lys, is not aminoacylated invivo to a measurable extent in 1 hr, although it is present in the tRNA prepared from the cells. All six isoacceptors are aminoacylated with [3H]lysine invivo when the labeling period is 2 or 3 hr. These results further show that invitro correlations of the amount of tRNA4Lys with cell division accurately reflect the situation invivo. Results of differential centrifugation indicate that tRNA6Lys occurs in mitochondria.  相似文献   

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Simian virus 40 minichromosomes, isolated from both virions (MV) and infected cells (MI), have highly compact structures in buffer containing 0.15 M NaCl and sediment with S values of about 90–100 and 115–130, respectively. Under the electron microscope, also, MI appear the more compact of the two. Only 30–35% of the sites of origin and termination of replication in MV are freely available to the restriction endonucleases Bgl 1 and Bam H1. MV are similarly resistant to Eco R1 and Hpa II. In contrast, almost no sites in MI are available to any of the above single-cut endonucleases. In 0.6 M NaCl, MV and MI change to relaxed structures of 45–55 S and 50–60 S, respectively, containing 20–24 nucleosomes per genome, and become more sensitive to Bgl 1, Bam H1, Eco R1, and Hpa II.  相似文献   

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15.
Ribosomal proteins L7L12 have been mapped by immune electron microscopy. These multiple copy proteins are located at a single region extending from the large subunit, known as the L7L12 stalk. The L7L12 stalk is approximately 100 Å long, about 40 Å wide and extends at an angle of approximately 50 ° from one side of the central protuberance of the large subunit. In the monomeric 70 S ribosome, the portion of the L7L12 stalk proximal to the 50 S subunit is located in the vicinity of the 30 S-50 S interface.Anti-L7L12 antibody binding to the stalk was shown to be solely dependent upon the presence of L7L12 by the following experiments. Sucrose gradient analysis was used to demonstrate that large subunits depleted of L7L12 were unable to bind anti-L7L12 antibodies and that re-incorporation of L7L12 restored the ability of L7L12-depleted cores to react with anti-L7L12 antibodies. Anti-L7L12 antibodies pre-absorbed with L7L12 did not react with 50 S subunits.Anti-L7L12 antibodies used in these experiments reacted only with the L7L12 stalk and with no other region of the subunit. This was shown by electron microscopy and by immune electron microscopy in the following ways. Electron microscopy of 50 S subunits, L7L12-depleted 50 S cores, and reconstituted 50 S subunits was used to demonstrate that stripping removes the L7L12 stalk from more than 95% of the subunits, and that re-incorporation of L7L12 into depleted cores restores the L7L12 stalk. Double-labelling experiments, using monomeric subunits with two or more attached anti-L7L12 immunoglobulins, were used to demonstrate, independently of 50 S subunit morphology, that L7L12 are located only on the L7L12 stalk.  相似文献   

16.
The alignment of cholesteryl esters in multilayer phosphatidylcholine membranes was investigated using two spin-labelled cholesteryl esters: 10 : 3 ester (I) and 1 : 14 ester (II). The nitroxide label of I is aligned in the membrane with a very large angle of tilt (47° ± 1.5°) with respect to the normal to the membrane surface; II does not show such a tilt. I gives spectra corresponding to immobilized label while II gives nearly isotropic spectra. Ascorbate treatment of the multilayers shows that the labels in I and II are not present at the phosphatidylcholine-water interphase.The data supports a ‘horseshoe’ configuration for the cholesteryl ester in the bilayer, with both the fatty acid chain and the cholesteryl moiety extending deep into the hydrophobic region of the membrane and with the ester linkage near the surface.  相似文献   

17.
A high molecular weight protein from the brush border of chicken intestinal epithelial cells has been purified. This protein (TW 260240), a complex of two polypeptides with apparent molecular weights of 260,000 and 240,000, accounts for a significant amount of the terminal web organization. TW 260240 is an F-actin-binding protein that also interacts with calmodulin. Rotary shadowing reveals long flexible rods of double-stranded morphology tightly connected at each end. TW 260240 is quite distinct from smooth muscle filamin and macrophage actin-binding protein (APB), but, in spite of its higher contour length (265 nm), seems to be related to erythrocyte spectrin (194 nm for the tetramer). Immunofluorescence microscopy with antibodies against TW 260240 indicates the existence of a submembranous organization distinctly different from that of stress fibers. We have compared TW 260240 with fodrin, a brain protein known to occur in submembranous organization but not previously characterized in molecular terms. TW 260240 and fodrin are clearly distinct molecules but are similar in many aspects. Ultrastructural, biochemical and immunological results indicate three distinct classes of rod-like high molecular weight actin-binding proteins, possibly reflected by the prototypes filamin (ABP), spectrin and TW 260240 (fodrin). The latter group may be responsible for calmodulin control of submembranous microfilament structures in various nonmuscle cells.  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.
Identification of opiate receptor binding in intact animals.   总被引:1,自引:0,他引:1  
C B Pert  S H Snyder 《Life sciences》1975,16(10):1623-1634
After intravenous administration of 3H-naloxone to rats, particulate bound radioactivity accumulated in the brain is selectively associated with opiate receptor binding sites, providing a means of labeling the opiate receptor in vivo. The regional distribution of 3H-naloxone bound in vivo closely parallels regional differences in opiate receptor binding in vitro with highest levels in the corpus striatum, negligible receptor-associated binding in the cerebellum and intermediate levels in other regions. 3H-Naloxone binding in vivo is saturable with the same total number of binding sites determined in vivo as by in vitro procedures. Nalorphine is markedly more potent than morphine in inhibiting 3H-naloxone binding in vivo and non-opiates are ineffective. The half-life for dissociation of 3H-naloxone bound to particles in vivo is the same as its dissociation rate after binding occurs in vitro, and sodium stabilizes 3H-naloxone bound in vivo from initial rapid dissociation as predicted from the known properties of the opiate receptor in vitro.  相似文献   

20.
G J Smith  P H Pearce  I T Oliver 《Life sciences》1976,19(11):1763-1775
A particulate factor of rat liver is described which interconverts three forms of rat liver cytosolic tyrosine aminotransferase invitro with no alteration of enzyme activity. The factor appears to be a heat- and pH-sensitive lysosomal protein. The interconversion process is stimulated invitro by 2.5 mM MgCl2 and 2.5 mM ATP. Asparate aminotransferase multiple forms are also susceptible to invitro interconversion by the lysosomal factor. The properties of the factor explain several anomalous effects of invitro manipulation on the tyrosine aminotransferase forms which have been reported in the literature and implicate the form interconversion in the degradation of tyrosine aminotransferase.  相似文献   

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