共查询到20条相似文献,搜索用时 62 毫秒
1.
T. Sasaki M. Yamasaki B. Maruo Y. Yoneda K. Yamane A. Takatsuki G. Tamura 《Biochemical and biophysical research communications》1976,70(1):125-131
Several tunicamycin resistant mutants were obtained from NA64. One of them, B7 strain produced a 5-fold larger amount of α-amylase than NA64 did. Only the amount of α-amylase, among excreted proteins, was enhanced. Genetic analyses by transformation suggested that a single mutation in B7 induced both resistance to tunicamycin and hyperproductivity of extracellular α-amylase. 相似文献
2.
R.Kennedy Keller Glenn D. Swank 《Biochemical and biophysical research communications》1978,85(2):762-768
In order to examine the role of carbohydrate in the secretion of ovalbumin, oviduct minces were incubated in the presence of tunicamycin, an inhibitor of dolichol-mediated glycosylation. Ovalbumin secretion was monitored immunologically and found to be identical, within experimental error, in the absence and presence of tunicamycin. These results, coupled with the recent finding of Palmiter . [Proc. Natl. Acad. Sci. (1978) , 94–98] indicate that neither a transient hydrophobic pre-piece nor carbohydrate is required for ovalbumin secretion. 相似文献
3.
The molecular weight of the precursor polyprotein to the envelope proteins of Rauscher murine leukemia virus is reduced from 85,000 to 68,000 daltons when synthesized in the presence of tunicamycin, a specific inhibitor of the synthesis of oligosaccharides that attach to glycoproteins via asparagine residues. The unglycosylated precursor protein (Pr68) is synthesized at a rate comparable to that of the normal carbohydrate-containing envelope precursor (gPr85). Pr68 is not proteolytically processed and remains undegraded in the cell. Thus, most if not all of the carbohydrate content of gPr85 is N-linked, and glycosylation appears to be necessary for normal processing of precursor proteins into viral particles. 相似文献
4.
Robert E. Lynch Barry C. Cole 《Biochemical and biophysical research communications》1980,96(1):98-105
Superoxide dismutase and catalase were not detected in . and several other species of some of which consume oxygen and secrete H2O2. . in suspension formed O2? in the presence of NADH and flavins and extracts of . formed O2? in the presence of either NADH or NADPH. The lack of superoxide dismutase in . could not be attributed to superoxide dismutase in the complex medium in which the organisms were grown because organisms grown in medium in which the superoxide dismutase had been inactivated by heat still contained undetectable amounts. Mycoplasmas appear to be an exception to the rule that organisms which consume O2 synthesize superoxide dismutase. 相似文献
5.
S.A. Voelkel K.W. Stuckey C.R. Looney F.M. Enright P.E. Humes R.A. Godke 《Theriogenology》1983,19(3):355-366
Two experiments were conducted to test for the recovery of brucella organisms from uterine flushings and harvested embryos of sero-positive embryo donor females. In Experiment I, 16 sero-positive cows were superovulated with FSH treatments and artificially inseminated at 12, 24 and 36 hours following the onset of estrus with brucella-free semen. At 48 hours after the onset of estrus, one half the potential donor females were administered an intrauterine inoculation of 3.3 to 4.6 × 104 (strain 2308) organisms while the remainder received a control inoculation. In Experiment II, the same 16 cows were similarly administered superovulatory treatments and inseminated following estrus. The uterine inoculation was increased to 1.5 to 2.5 × 108 organisms administered 48 hours following estrus. Samples of recovered flushing medium and homogenized embryo residues were placed into a validated culture system to detect the presence of brucella bacteria. Uterine flushings and embryos recovered from 31 females exhibiting estrus following FSH treatments were free from either field strain or the inoculated (strain 2308) contamination. The flushings obtained from a single female, which did not respond with estrus following FSH treatment but was inoculated at appointment, did contain which was identified as the inoculated strain 2308 and not field strain organisms. These results indicate that brucella contamination of flushing media and harvested embryos will not likely be incurred when collecting embryos from sero-positive donor females. These findings offer further encouragement for the use of embryo transplantation as a method to produce brucella-free offspring from infected cows. 相似文献
6.
Kenji Kohno Akiyoshi Hiragun Akira Takatsuki Gakuzo Tamura Hiromi Mitsui 《Biochemical and biophysical research communications》1980,93(3):842-849
ST 13 cells are a clonal line of murine fibroblasts that are capable of differentiating into adipocyte-like cells . When the cells were maintained as a confluent monolayer, they began to accumulate lipid droplets and to exhibit a rapid increase of insulin binding activity. Tunicamycin, a specific inhibitor of dolichol-mediated protein glycosylation, blocked this adipose conversion without affecting cell growth and total protein synthesis. The inhibitory effect of tunicamycin was dose-dependent and reversible. Enhancement of the incorporation of [14C]acetate into triglyceride fraction accompanying the adipose conversion was completely inhibited by tunicamycin, whereas the incorporation into phospholipid fraction was only partially affected. The insulin binding activity increased about 10-fold during differentiation, but was completely suppressed in tunicamycin-treated cells. 相似文献
7.
Electron spin resonance detection of free radicals in the mercaptan-activation and UV-inactivation of neocarzinostatin 总被引:3,自引:0,他引:3
Differentiation of chick embryo myoblasts requires both cell-cell recognition and cell-cell fusion. Prostaglandin E1 is known to play a role in controlling fusion, and a specific receptor has been postulated. We demonstrate two peaks of specific binding activity for prostaglandin E1 during myoblast differentiation : one at 36 hours and one at 44 hours of culture. The prostaglandin binding activity of both peaks is sensitive to the inhibitors of prostaglandin synthesis, indomethacin and aspirin, and to the antibiotic tunicamycin. The 36 hour peak of binding activity occurs at the same time as the process of cell-cell recognition (24–36 hours) and recognition and prostaglandin binding exhibit similar sensitivity to indomethacin, aspirin and tunicamycin. 相似文献
8.
Uzi Reiss Morton Rothstein 《Biochemical and biophysical research communications》1974,61(3):1012-1016
The temperature stabilities of pure isocitrate lyase, isolated from young and old , have been compared. The “old” enzyme shows the presence of a heat-labile component lacking in the enzyme derived from young organisms. This component has been shown to be associated with two of the five isozymes comprising the isocitrate lyase. A mechanism is proposed which might account for the presence of altered enzymes in aged organisms. 相似文献
9.
OKY-1581 is an effective inhibitor of thromboxane synthesis and . 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 or 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
10.
11.
Cycloheximide, colchicine, tunicamycin, glucagon, dibutyryl-3′–5′-cyclic AMP, dexamethasone and hydrocortisone had no effect on the lipoprotein lipase activity associated with rat cardiac muscle cells incubated . However, the steroid hormones and inhibitors affected profoundly the appearance of extracellular enzyme during the incubations. The pattern of effects, was consistent with lipoprotein lipase being a normal secretory product of heart muscle cells. 相似文献
12.
Prostaglandin synthesis in rat embryo tissue: The effect of non-steroidal anti-inflammatory drug and
Kenneth L. Klein Kenneth E. Clark William J. Scott 《Prostaglandins & other lipid mediators》1984,27(5):659-672
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 and 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-PGF1α, PGE, and PGF in large amounts from endogenous substrate, that aspirin and other non-steroidal anti-inflammatory drugs inhibit PG synthesis but not necessarily , 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
13.
H. Engelberg-Kulka L. Dekel M. Israeli-Reches 《Biochemical and biophysical research communications》1981,98(4):1008-1015
The regulation of the synthesis of operon enzymes was studied in streptomycin-resistant mutants temperature-sensitive for UGA suppression by normal tRNATrp. Our mutants carry a allele that when transferred to a different genetic background causes repression of trp operon enzyme synthesis at both low (35°C) and high (42°C) temperatures; however, in our mutants with an excess of tryptophan and at increased temperatures enzyme synthesis is derepressed. Based on our results and the sequence data of the R gene [Singleton et al. (1980) Nucleic Acids Res., 8, 1551–1560], we offer a model for the involvement of the limited misreading of UGA codons by normal charged tRNATrp in the autogenous regulation of the R gene expression. The UGA readthrough process may be a regulatory amplifier of the effect of tryptophan starvation. 相似文献
14.
Motiram R. Dhawale Ernest H. Creaser 《Biochemical and biophysical research communications》1976,71(4):901-906
In order to investigate the control mechanism of histidinol dehydrogenase [HDH(I)] induction in , growth curves and induction experiments were carried out in presence of inhibitors of protein synthesis, namely chloramphenicol and actinomycin D. The evidence obtained from the gel electrophoresis patterns of the HDH activities in extracts of cultures suggest that HDH(I) induction is regulated at the protein synthesizing complex level rather than at mRNA synthesis. A working model is proposed to explain the mode of control of HDH formation in this bacterium, which involves stable messenger formation and post-translation control by histidinol. 相似文献
15.
《Biochimica et Biophysica Acta (BBA)/General Subjects》1979,587(4):515-521
Pent-4-enoate at 0.1 to 1.0 mM strongly inhibited urea synthesis in isolated rat hepatocytes. Pent-4-enoate at the same concentrations markedly decreased concentrations of , an essential activator of carbamoyl-phosphate synthase-I (EC 2.7.2.5), and the decrease was well parallel with the inhibition of urea synthesis by pent-4-enoate. This compound also lowered cellular concentrations of acetyl-CoA, a substrate of acetylglutamate synthase (EC 2.3.1.1). Pent-4-enoate in a dose of 1 mM did not significantly affect cellular concentrations of ATP, and had no direct effect on acetylglutamate synthase activity. These results suggest that the inhibition of urea synthesis by pent-4-enoate is due to decrease in concentration and that the decrease is probably brought about by decreased rate of its synthesis due to the lowered concentration of cellular acetyl-CoA. 相似文献
16.
W. Maier D. Erge B. Schumann D. Gröger 《Biochemical and biophysical research communications》1981,99(1):155-162
A cell-free system of has been described which incorporates [14C] leucine into the peptide-type ergot alkaloid ergosine. Cell-free extracts may be prepared either from protoplasts or lyophilized mycelium. Production was markedly stimulated by addition of agroclavine compared with d-lysergic acid and by agitation of the incubation mixture. The synthesis of ergosine is strongly dependent on the presence of ATP in the reaction mixture. 相似文献
17.
Gianfranco Badaracco Paolo Plevani Giovanni Cassani 《Biochemical and biophysical research communications》1981,99(1):23-29
The rate of synthesis of poly(A) on a ply(dT) template by RNA polymerase is a function of ATP concentration and is expressed as a sigmoidal curve. The addition of millimolar concentration of AMP to low concentrations of ATP stimulates synthesis of poly(A) twenty fold and raises the rate of synthesis to the levels obtained at high ATP concentrations. The reaction is completely dependent upon the presence of poly(dT) and requires the complementary mononucleotide. Stimulation of poly(A) synthesis by AMP is more evident with the holoenzyme. Analysis of poly(A) products by acrylamide gels showed that the poly(A) synthesized in the presence of AMP has an higher molecular weight than poly(A) synthesized in the absence of AMP. 相似文献
18.
The specific synthesis of F mRNA directed by the F gene carried on the specialized transducing bacteriophage F, performed , is described with the use of an S180 extract from a strain carrying R?. Synthesis of F mRNA is biphasic at approximately 7 minutes. The regulation of F mRNA synthesis by the specific arginine holorepressor present in an S180 extract prepared from a strain carrying the R+ allele is described. 相似文献
19.
Dileep S. Sachan Harry P. Broquist 《Biochemical and biophysical research communications》1980,96(2):870-875
An enzyme system in the post mitochondrial fraction of when supplemented with appropriate cofactors formed carnitine from ε-N-trimethyllysine. These findings together with previous studies of ε-N-lysine methylation in this fungi, illustrate that carnitine synthesis in differs markedly in certain features from mammalian systems in that the entire synthesis is carried out employing free intermediates and cytosolic enzymes. 相似文献
20.
Yuji Kamiya Akira Sakurai Saburo Tamura Nobutaka Takahashi Keiko Abe Eiko Tsuchiya Sakuzo Fukui Chieko Kitada Masahiko Fujino 《Biochemical and biophysical research communications》1978,83(3):1077-1083
Rhodotorucine is a peptidyl factor which induces mating tube formation in . The amino acid sequence of the factor was determined by Edman degradation and enzymatic hydrolysis. Rhodotorucine was shown to contain a lipophilic amino acid, S-farnesyl cysteine, at C-terminus by proton magnetic resonance, mass spectrometry and chemical synthesis. We proposed the following structure for rhodotorucine . H-Tyr-Pro-Glu-Ile-Ser-Trp-Thr-Arg-Asn-Gly-Cys(S-farnesyl)-OH 相似文献