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1.
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   

2.
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   

3.
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   

4.
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   

5.
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   

6.
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   

7.
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   

8.
Evidence is presented for the presence of a new lectin activity in soybean seeds [Glycinemax (L.) Merrill] that has specificity towards the 4-O-methyl-D-glucurono-L-rhamnan exopolysaccharide produced by certain strains of Rhizobiumjaponicum. 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-O-methyl-D-glucuronic acid, D-glucuronic acid and their methyl glycosides.  相似文献   

9.
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   

10.
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   

11.
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   

12.
The plasma membrane-bound penicillinase of Bacilluslicheniformis749C has been purified. Amino acid analysis showed no significant differences in composition between the enzyme and exopenicillinase. Enzyme purified from cultures containing H333PO4 or [3H]-glycerol contained 33P or [3H]-glycerol activity and treatment with 8 M urea, 0.2% sodium dodecyl sulfate at 80° C did not remove the 3H-activity from the enzyme protein. Trypsin readily cleaved the glycerol-containing moiety from the enzyme protein, forming enzyme with molecular weight and heat stability like that of the exoenzyme. Phospholipase D and C also produced enzyme resembling the exo-form.  相似文献   

13.
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   

14.
The pesticide o,p'-DDT stimulates the production of a specific uterine protein, the so-called induced protein or IP, normally associated with an estrogenic response of the uterus. Invivo stimulation of IP production is observed 1 hour after the administration of 250 mg/kg of o,p'-DDT to immature rats. Invitro stimulation of IP production is observed after a 1 hour incubation of uteri with 100 μM o,p'-DDT. This invitro response is blocked by Actinomycin D. In contrast to o,p'-DDT, which binds to the cytoplasmic estrogen receptor and stimulates IP production, p,p'-DDT which does not bind well to the estrogen receptor does not stimulate IP production invitro. These findings represent the first report of an estrogenic effect of o,p'-DDT in a completely invitro system.  相似文献   

15.
The semi-soft agar colony assay permits an invitro analysis of committed myeloid stem cell (CFU-c) proliferation capacities. In this paper this procedure has been used in combination with prior diffusion chamber culturing to determine the effect of host influences upon this committed stem cell population. This “double-seeding” procedure of first culturing bone marrow cells in diffusion chambers and then re-seeding them in agar furnishes data suggesting a relationship between invivo diffusion chamber transitional lymphocytes and invitro CFU-c seeding capacities. Diffusion chamber culturing offers a means of monitoring granulopoiesis and selects for enrichment of stem cell numbers. Detection and quantification of diffusion chamber stem cell enrichment is easily assessed by seeding chamber contents into the agar colony assay.  相似文献   

16.
Extracts of 40 hr Artemiasalina nauplii can convert a heavy form of elongation factor 1 (EF-1H) to a light species (EF-1L). The data indicate that a protease in the extracts is responsible for this reaction, and these findings may explain the observation that extracts from Artemiasalina nauplii have only EF-1L whereas before hatching of the Artemiasalina embryos EF-1H is the predominant species (Slobin and M?ller [1975] Nature 258, 452–454).  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.
Guanylate cyclase from crude homogenates of vegetative Dictyosteliumdiscoideum 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   

19.
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   

20.
Timothy G. Kingan 《Life sciences》1981,28(23):2585-2594
Standard biochemical procedures were used to purify the prothoracicotropic hormone (PTTH) 4400 fold from whole head extracts of Mandurasexta fifth instar larvae. Hormonal activity was bioassayed by injection into neck-ligated fourth instar larvae. The hormone was stable to heating at 85°C. Ammonium sulfate and acetone fractionation provided a crude preparation which showed dose-dependent activity in the bioassay. Chromatography on Sephadex G-100, DEAE-Sephadex, and hydroxylapatite gave a preparation with 2.6 Manduca PTTH units/μg protein (4400-fold purification). Activity was sensitive to proteolytic enzymes. Further purification by preparative electrophoresis gave a preparation which migrated as a single band in two polyacrylamide gel electrophoresis systems. A molecular weight estimate of 25,000 Daltons was obtained for this bands on SDS polyacrylamide gels.  相似文献   

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