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61.
Genetic structure of the IncN plasmid N3 总被引:4,自引:0,他引:4
N3, a plasmid of incompatibility group N (IncN) was mapped by cleavage with restriction endonucleases. The restriction fragments were cloned into vector plasmids. All of the genes unique to IncN plasmids such as specific replication machinery, a restriction-modification system, and repair functions were located on a large portion which had no cleavage sites for many of the site-specific six base-identifying restriction endonucleases tested. 相似文献
62.
Interaction of basic oligo-L-amino acids with deoxyribonucleic acids. Oligo-L-arginines of various chain lengths and herring sperm DNA 总被引:1,自引:0,他引:1
The interaction of DNA and oligo-L-arginines having definite chain lengths of 1-17 residues was studied by precipitate formation and thermal denaturation of the complexes in order to obtain a better understanding of the roles of nuclear basic proteins. The results can be summarized as follows. 1. Those oligo-L-arginines, (Arg)n, in which n greater than or larger than 4 can bind with DNA irreversibly to form precipitates of the complexes. Among them, oligomers larger than (Arg)5 precipitate DNA completely in Arg/P input ratios below 1. The Arg/P ratios in the precipitates are between 0.6-0.8. 2. The thermal stability of the complexes depends on the method of complex formation, and complexes formed by the dialysis method are more stable than those formed by the mixing method. 3. The binding of (Arg)n to DNA was found to be reversible and in a equilibrium for n less than or equal to 6. In general, the longer the oligomer, the higher the stability of the complex at a definite Arg/P ratio. 4. For (Arg)7-10, three kinds of complexes with different stabilities are formed between DNA and oligopeptides. 5. For (Arg)14-17, only a restricted type of complexes can be formed between DNA and oligomers, as in the case with poly-L-arginine or protamines. 6. The interaction between basic nuclear proteins and DNA is discussed in the light of the basic region in protamine and histone molecules. 相似文献
63.
Masato Hirata Eiichi Suematsu Toshitaka Koga 《Biochemical and biophysical research communications》1982,105(3):1176-1181
The Ca2+ uptake of the mitochondria of guinea pig peritoneal macrophages was not stimulated by the addition of calmodulin. However, calmodulin antagonists, both phenotiazines and N-naphthalenesulfonamides, in low concentrations inhibited the Ca2+ uptake of the mitochondoria, as compared to the inhibition of the calmodulin-dependent stimulation of brain phosphodiesterase. These calmodulin antagonists appear to have severe side effects on active processes of the mitochondria and which are unrelated to the specific effect on calmodulin. 相似文献
64.
Masato Hirata Toshitaka Koga 《Biochemical and biophysical research communications》1982,104(4):1544-1549
Ca2+ transport system in the intracellular membranes was studied by using saponin-treated macrophages of the guinea pig, in which the plasma membranes could be selectively destroyed. Saponin-treated macrophages could accumulate 3.1 nmoles macrophages in the presence of Mg-ATP and sodium azide with an apparent affinity constant of 6 × 106 M?1. In the absence of sodium azide, the value of Ca2+ uptake of saponin-treated macrophages was 95 nmoles/4 × 106 macrophages, and its affinity constant for Ca2+ was 3 × 105 M?1. Saponin-treated macrophages may be suitable for the studies of Ca2+ transport systems in the intracellular membranes. 相似文献
65.
Masato Hirata Takafumi Hamachi Eiichi Suematsu Toshitaka Koga 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》1983,763(4)
Effects of N-formyl chemotactic peptides on the Ca2+ influx and efflux were investigated in guinea-pig peritoneal macrophages using an isotope tracer. fMet-Leu-Phe did not enhance the influx of 45Ca2+ into macrophages, whereas it stimulated the efflux of 45Ca2+ from macrophages at concentrations ranging from 10−10 M to 10−7 M. fMet-Met-Met and fMet-Leu also stimulated the 45Ca2+ efflux, albeit at much higher concentrations, while there was no stimulation with fMet. The mitochondrial inhibitors, oligomycin and NaN3, did not modify the 45Ca2+ efflux induced by the chemoattractants, yet they did induce the release of 45Ca2+ from the mitochondria. On the other hand, higher concentrations of the calmodulin antagonists, chlorpromazine and trifluoperazine, induced the release of 45Ca2+ from the NaN3-insensitive Ca2+ store site and mimicked the enhancement of the 45Ca2+ efflux by N-formyl chemotactic peptides. Thus, N-formyl chemotactic peptides appear to increase the levels of intracellular free Ca2+ in guinea-pig peritoneal macrophages, probably by inducing the release of Ca2+ from the NaN3-insensitive Ca2+ store site. 相似文献
66.
Masato Hirata Takafumi Hamachi Eiichi Suematsu Toshitaka Koga 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》1983,763(4):339-345
Effects of N-formyl chemotactic peptides on the Ca2+ influx and efflux were investigated in guinea-pig peritoneal macrophages using an isotope tracer. fMet-Leu-Phe did not enhance the influx of 45Ca2+ into macrophages, whereas it stimulated the efflux of 45Ca2+ from macrophages at concentrations ranging from 10?10 M to 10?7 M. fMet-Met-Met and fMet-Leu also stimulated the 45Ca2+ efflux, albeit at much higher concentrations, while there was no stimulation with fMet. The mitochondrial inhibitors, oligomycin and NaN3, did not modify the 45Ca2+ efflux induced by the chemoattractants, yet they did induce the release of 45Ca2+ from the mitochondria. On the other hand, higher concentrations of the calmodulin antagonists, chlorpromazine and trifluoperazine, induced the release of 45Ca2+ from the NaN3-insensitive Ca2+ store site and mimicked the enhancement of the 45Ca2+ efflux by N-formyl chemotactic peptides. Thus, N-formyl chemotactic peptides appear to increase the levels of intracellular free Ca2+ in guinea-pig peritoneal macrophages, probably by inducing the release of Ca2+ from the NaN3-insensitive Ca2+ store site. 相似文献
67.
S Abe S Araki M Satake N Fujiwara K Kon S Ando 《The Journal of biological chemistry》1991,266(15):9939-9943
A phosphonoglycosphingolipid, named F-21, was found in the nervous system of Aplysia kurodai by two-dimensional thin-layer chromatography (Abe, S., Araki, S., and Satake, M. (1986) Biomed. Res. (Tokyo) 7, 47-51). F-21 was isolated from the nervous tissue of Aplysia in this study, and its chemical structure was characterized as follows, where 2-AEP is 2-aminoethylphosphonate. (Formula; see text) The major aliphatic components of the ceramide portion were palmitic acid (75%), stearic acid (22%), octadeca-4-sphingenine (43%), and anteisononadeca-4-sphingenine (54%). Some information on the steric interactions in the sugar moiety was obtained by NMR spectroscopy. The ring protons of the internal galactose, H1, H3, and H4 and the H3 of the side chain galactose were shifted, as compared to the corresponding protons of dephosphonylated F-21. This may indicate the interactions between the 2-AEP residue of N-acetylgalactosamine and the internal galactose and between the N-acetyl group of N-acetylgalactosamine and the side chain galactose, implying a sterically restricted and unique structure that may relate to some biological functions of F-21. 相似文献
68.
The functional GABAB receptor was expressed in Xenopus oocytes by injecting mRNA obtained from the cerebellum of the rat. Application of GABA in the presence of bicuculline induced a hyperpolarization under current-clamp conditions and an outward current under voltage-clamp conditions. Baclofen mimicked the effect of GABA in the presence of bicuculline, and the effect of baclofen was antagonized by phaclofen. The GABA-induced outward current was slightly inhibited by treatment with GDP-beta-S and was completely inhibited by treatment with GTP-gamma-S. The activation of protein kinase C by 12-O-tetradecanoylphorbol-13-acetate (TPA), but not 4 alpha-phorbol-12,13-didecanoate, suppressed the GABAB receptor-mediated hyperpolarization, and the effect of TPA was antagonized by sphingosine. Thus, activation of protein kinase C inhibits the expressed GABAB receptor-mediated response. 相似文献
69.
We have reported the existence of a phosphonoglycosphingolipid containing a pyruvylated galactose, FGL-IIb, in nerve fibers of Aplysia kurodai (Araki, S., Abe, S., Ando, S., Kon, K., Fujiwara, N. & Satake, M. (1989) J. Biol. Chem. 264, 19922-19927). We have now isolated two other pyruvylated galactose-containing phosphonoglycosphingolipids, named FGL-V and FGL-IIa, from the nervous tissue of Aplysia, and characterized them as [3,4-O-(S-1-carboxyethylidene)]Gal beta 1----3GalNAc alpha 1----3[6'-O-(2- aminoethylphosphonyl)Gal alpha 1----2] (2-aminoethylphosphonyl----6) Gal beta 1----4Glc beta 1----1 ceramide and [3,4,O-(S-1-carboxyethylidene)] Gal beta 1----3GalNAc alpha 1----3[6'-O-(2-aminoethylphosphonyl)Gal alpha 1----2]Gal beta 1----4Glc beta 11----ceramide, respectively. Their major aliphatic components are palmitic acid, octadeca-4-sphingenine and anteisononadeca-4-sphingenine. Thus, the nervous system of Aplysia contains several pyruvylated phosphonoglycolipids. 相似文献
70.
T Mizuno K Kaibuchi S Ando T Musha K Hiraoka K Takaishi M Asada H Nunoi I Matsuda Y Takai 《The Journal of biological chemistry》1992,267(15):10215-10218
The superoxide-generating NADPH oxidase system in phagocytes consists of at least membrane-associated cytochrome b558 and three cytosolic components named SOCI/NCF-3/sigma 1/C1, SOCII/NCF-1/p47-phox, and SO-CIII/NCF-2/p67-phox. p47-phox and p67-phox were isolated, and their primary structures were determined, but SOCI has not been well characterized. In the present study, we first purified SOCI to homogeneity from the cytosol fraction of the differentiated HL-60 cells. The purified SOCI was a small GTP-binding protein (G protein) with a M(r) of about 22,000. The guanosine 5'-(3-O-thio)triphosphate-bound form, but not the GDP-bound form, of this small G protein showed the SOCI activity. The partial amino acid sequence of SOCI thus far determined was identical to the amino acid sequence deduced from the cDNA encoding rac2 p21. None of the purified small G proteins, including Ki-ras p21, smg p21B/rap1B p21, rhoA p21, and rac1 p21, showed the SOCI activity. These results indicate that SOCI is a small G protein very similar, if not identical, to rac2 p21. The GDP/GTP exchange reaction of SOCI was stimulated and inhibited by stimulatory and inhibitory GDP/GTP exchange proteins for small G proteins, named smg GDS and rho GDI, respectively. The NADPH oxidase activity was also stimulated and inhibited by smg GDS and rho GDI, respectively. These results indicate that the superoxide-generating NADPH oxidase system is regulated by both smg GDS and rho GDI through rac2 p21 or the rac2-related small G protein in phagocytes. 相似文献