共查询到20条相似文献,搜索用时 15 毫秒
1.
Kazuo Yoshida Michio Hagiya Naohiko Yanagishima 《Biochemical and biophysical research communications》1976,71(4):1085-1094
The substance responsible for the sexual agglutinability was successfully solubilized by a newly established autoclaving method from the surface of mating type cells of and purified by DEAE cellulose chromatography, gel filtration, affinity chromatography and electrophoresis. The substance was found to consist of at least two different glycoprotein subunits. The molecular weight of the substance was estimated to be about 23,000 daltons by gel filtration. The substance was univalent in its biological activity and specifically masked the sexual agglutinability of the mating type α cells. The substance formed a complementary complex with the agglutination substance from α cells in vitro. 相似文献
2.
N. Marmiroli F. Restivo E. Zennaro P.P. Puglisi 《Biochemical and biophysical research communications》1976,70(2):589-594
The temperature, as well as several antibacterial antibiotics could be used to differentiate mitochondrial protein synthesis (MPS) from the cytoplasmic (CPS) one in the yeast . In fact MPS and CPS have respectively the optimum at 30°C and 36°C. A series of cellular processes, as the mitotic reproduction in presence of non-fermentable carbon sources, the synthesis of galactose pathway enzymes and the meiotic process have the same optimal temperature (30°C), whereas the growth of the wild type in presence of fermentable carbon sources and of a galactose repressor constitutive mutant (i-) have the optimal temperature of 36°C, in agreement with our previous hypothesis in which the expression of some sections of the nuclear genetic complement is dependent on regulatory functions controlled by MPS. 相似文献
3.
M. Bard R.A. Woods J.M. Haslam 《Biochemical and biophysical research communications》1974,56(2):324-330
The , and mutants of yeast require an unsaturated fatty acid and methionine for growth and do not synthesise ergosterol. They have very similar sterol compositions and all accumulate lanosterol. The mutants lack cytochrome pigments and have negligible respiratory activity. Porphyrin intermediates alleviate the lipid requirement of and and restore respiratory competence. It is concluded that the primary defects in these mutants are lesions in porphyrin biosynthesis. 相似文献
4.
G. León^Rivera M.Pérez Gosalbez J.P.G. Ballesta 《Biochemical and biophysical research communications》1980,94(3):800-806
Ribosomes from wild type (Y166) and trichodermin (TR1) and narciclasine (NAR2b) resistant strains were affinity labeled with p-nitrophenylcarbamyl-(3H)Phe-tRNA. Resistant ribosomes were able to bind covalently two to five times more aminoacyl-tRNA derivative than control. The labeling pattern of the individual ribosomal proteins was also altered in the two mutants. These results evidence a change in the conformation of the peptidyl transferase center that brings the 3′ end of the aminoacyl-tRNA closer to several ribosomal proteins. 相似文献
5.
Evelyn A. Devine Mary C. Moran Peter J. Jederlinic Anthony J. Mazaitis Henry J. Vogel 《Biochemical and biophysical research communications》1975,67(4):1589-1593
The transducing phage λd, carrying a portion of the chromosome including , is derived from the heat-inducible, lysis-defective strain λy199, which has the and deletions. Cleavage of λy199 DNA by RI 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 minus , the cleavage site between A and B being eliminated). Cleavage of λd DNA by RI 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 cluster is on the 14-1 segment. 相似文献
6.
In an attempt to isolate and to study the electron transport system of , we have isolated and purified a membrane-bound cytochrome . The cytochrome , 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 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 was demonstrated to be spectrally distinguishable from both the oxidized and the reduced forms. 相似文献
7.
Yuji Kamiya Akira Sakurai Nobutaka Takahashi 《Biochemical and biophysical research communications》1980,94(3):855-860
Rhodotorucine which induces mating tube formation of cells in is metabolized rapidly by cells. By use of labeled rhodotorucine , 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 cells at log phase did not metabolize rhodotorucine . 相似文献
8.
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
9.
Guanylate cyclase from crude homogenates of vegetative 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
10.
This case report addresses the occurrence of Brucellosis and its effect on the cattle in developing countries. Three Zebu bulls () 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. 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
11.
J.A. Pérez-González A. Jiménez 《Biochemical and biophysical research communications》1984,125(3):895-901
The paromomycin producing organism is resistant to this antibiotic and contains a phosphotransferase which inactivates paromomycin. The gene encoding this enzyme has been inserted in the vector pIJ702 and then cloned in , 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 cloning vectors with the versatility of insertional inactivation. 相似文献
12.
Ronald M. Hamelik Mead M. McCabe 《Biochemical and biophysical research communications》1982,106(3):875-880
An inhibitor of , endodextranase was detected in proteins prepared from batch cultures of , strains representing serotypes through . 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 , known to produce this enzyme. 相似文献
13.
Uterine stage embryos collected from the hamster (8-cell) and cow (morula, early blastocyst) were monitored for development (embryo culture) and (embryo transfer) following premature removal of the zona pellucida.Removal of the zona pellucida did not significantly affect 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 . Such fusion was observed to occur 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 and 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
14.
Robert C. Richmond John D. Zimbrick 《Biochemical and biophysical research communications》1975,64(1):391-398
Cells of C thy?321 are examined for thymine residue release from DNA following gamma-irradiation from 5 to 15 krad. Experimental conditions are designed to inhibit enzyme activity that might promote base residue release. Enzyme action is restricted in order to assess the physicochemical action of radiation on cellular DNA, and to this end irradiation is done under O2, N2, and N2O saturating conditions. Both thymine and thymidine release from bacterial DNA are detected and quantitated, and three oxygen effects are noted in comparing yields of these products. No difference in effect is observed between N2 and N2O gassing conditions, suggesting that the hydroxyl radical has little effect on thymine or thymidine release from irradiated DNA . 相似文献
15.
The synthesis and characterization of - and -3,4-bis(4-hydroxyphenyl)-2-hexene (- and -pseudo-DES) and of -3,4-bis(4-hydroxyphenyl)-2-hexen-1-ol (-1-hydroxypseudo-DES) are described. These compounds are useful as probes in the study of hormone action. 相似文献
16.
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
17.
The GDH (NADPH) mutant strain of has sizable pools of glutamine and glutamate under ammonium-limited conditions for which requires an elevated glutamine synthetase activity. Glutamine in the pre ence of 2-oxoglutarate, stimulated nicotinamide nucleotide oxidation by crude and purified extracts of the strain and led to a reductant dependent formation of two molecules of glutamate. Aminooxyacetate did not have any effect on the reaction, whereas azaserine inhibited it completely. It is concluded that in glutamine synthetase and glutamate synthase are responsible for the assimilation of low ammonium concentrations. 相似文献
18.
R. Rodriguez C. Lopez-Otin D. Barber J.L. Fernandez-Luna G. Gonzalez E. Mendez 《Biochemical and biophysical research communications》1982,108(1):315-321
The NH2-terminal amino acid sequence of the three anti-tumor proteins, alfa-sarcin, mitogillin and restrictocine, has been determined for 20 cycles by automated sequencing procedure. A high degree of sequence homology was observed in this region of the molecule. In addition, extensive sequence homology, ranging from 65 to 100% was found in three other carboxymethylcysteine-containing peptides isolated and sequenced from each molecule. 相似文献
19.
20.
Yolk free blastoderms of chick embryo were incubated 3 or 22 hours with labeled pregnenolone, progesterone, 17-hydroxyprogesterone, dehydro-epiandrosterone, androstenedione, testosterone and estradiol-17β. Metabolites and unconverted substrates were found both in the incubation medium and in the cells. Enzymes responsible for identified conversions were: 17α-hydroxylase, 17-20-desmolase, Δ53β- and 3α-hydroxysteroid dehydrogenase, 17β-hydroxysteroid dehydrogenase and 5α- and 5β-reductase. The results suggest that the steroid metabolizing enzyme activities found may reflect a more general ability of early embryonic cells. 相似文献