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81.
Guinea pig alveolar eosinophils and macrophages produce leukotriene B4 but no peptido-leukotriene 总被引:2,自引:0,他引:2
K Hirata K Maghni P Borgeat P Sirois 《Journal of immunology (Baltimore, Md. : 1950)》1990,144(5):1880-1885
The metabolism of arachidonic acid (AA) was investigated in purified guinea pig alveolar eosinophils and macrophages. Alveolar eosinophils produced 12S-hydroxy-5,8,10-heptadecatraenoic acid (HHT) and small amounts only of 5-lipoxygenase products when stimulated by AA (10 microM) or ionophore A23187 (2 microM). However, when the cell suspensions were stimulated with both AA and A23187, the cells produced HHT, leukotriene (LT) B4, and 5S-hydroxy-6,8,11,14-eicosatetraenoic acid, whereas LTC4, D4, and E4 were undetectable. Similarly, alveolar macrophages stimulated with A23187 produced HHT, 5-hydroxy-6,8,11,14-eicosatetraenoic acid, and LTB4 but no peptido-leukotrienes. When LTA4 was added to suspensions of eosinophils and macrophages, only LTB4 was formed, whereas in parallel experiments, intact human platelets incubated with LTA4 produced LTC4. These data suggest that guinea pig alveolar eosinophils and macrophages contain both cyclooxygenase and 5-lipoxygenase, but do not produce peptido-leukotrienes, probably lacking LTA4 glutathione transferase activity. These studies demonstrate that guinea pig eosinophils differ from eosinophils of other animal species which have been shown to be major sources of leukotriene C4. The present data imply that eosinophils and macrophages are not the source of peptido-leukotrienes in anaphylactic guinea pig lungs. 相似文献
82.
83.
Izaura Yoshico Hirata Maria Helena Sedenho Cezari Clovis Ryuichi Nakaie Paulo Boschcov Amando Siuiti Ito Maria Aparecida Juliano Luiz Juliano 《Letters in Peptide Science》1995,1(6):299-308
Summary A general procedure, using the commonly employed solid-phase peptide synthesis methodology for obtaining internally quenched fluorogenic peptides with ortho-aminobenzoyl/dinitrophenyl groups as donor-acceptor pairs, is presented. The essential feature of this procedure is the synthesis of an N
-Boc or-Fmoc derivative of glutamic acid with the -carboxyl group bound to N-(2,4-dinitrophenyl)-ethylenediamine (EDDnp), which provides the quencher moiety attached to the C-terminus of the substrate. The fluorescent donor group, ortho-aminobenzoic acid (Abz), is incorporated into the resin-bound peptide in the last coupling cycle. Depending on the resin type used, Abz-peptidyl-Gln-EDDnp or Abz-peptidyl-Glu-EDDnp is obtained. Using the procedure described above, substrates for human renin and tissue kallikreins were synthesised. Spectrofluorimetric measurements of Abz bound to the -amino group of proline showed that strong quenching of Abz fluorescence occurs in the absence of any acceptor group. 相似文献
84.
H Okamoto N Sone H Hirata M Yoshida Y Kagawa 《The Journal of biological chemistry》1977,252(17):6125-6131
1. The membrane-integrated portion (TF0) of the proton translocating ATPase complex (TF0-F1) of the thermophilic bacterium PS3 was highly purified. Its proton-conducting activity was investigated in vesicles reconstituted from TF0 and phospholipids (TF0 vesicles). 2. The rate of proton conduction through TF0 was proportional to the membrane potential imposed (6H+ uptake/s/TF0 molecule with 103 mV at pH 8.0). The pH profile of the rate revealed that a proton, not a hydroxy ion, was the true substrate conducted and that there was a monoprotic proton binding site in TF0 (pKa = 6.8). The temperature coefficient of proton conductance of TF0 showed a considerable variation depending on the phospholipids of the vesicles with respective transition temperatures. 3. Passive proton conduction through TF0 was inhibited stoichiometrically by addition of either the soluble ATPase portion (TF1) of TF0-F1, or an energy transfer inhibitor dicyclohexylcarbodiimide or an antibody against TF0. 4. The proton conductance of TF0 was concluded to represent its intrinsic activity in the original TF0-F1 complex. 相似文献
85.
The participation of superoxide anion (O2-) in the intracellular indoleamine 2,3-dioxygenase activity was studied using the dispersed cell suspension of the rabbit small intestine. The dioxygenase activity was assayed by measuring [14C]formate released from DL-[ring-2-14C]tryptophan. The addition of diethyldiethiocarbamate, a superoxide dismutase inhibitor, markedly accelerated the intracellular dioxygenase activity while the superoxide dismutase activity decreased concomitantly. Furthermore, substrates of xanthine oxidase such as inosine, adenosine, and hypoxanthine also increased the dioxygenase activity in the cells, particularly in the presence of methylene blue. This increase was completely abolished by the addition of allopurinol, a specific inhibitor of xanthine oxidase. These results, taken together, indicate that the intracellular accumulation of O2- results in acceleration of the in situ dioxygenase activity, and that indoleamine 2,3-dioxygenase utilizes O2- in the isolated intestinal cells. 相似文献
86.
Hironori Hirata 《Bulletin of mathematical biology》1980,42(1):119-130
A model of ecosystems with migration is proposed from the viewpoint of flow. This model explains the following two points:
(1) How the density-dependent terms in population dynamics arise as a consequence of migration. (2) How the ecosystem exhibits
a hierarchy in energy per unit biomass. 相似文献
87.
An improved method has been developed for fixation with potassium permanganate. Although this is one of the methods widely used to preserve the dense cores of adrenergic storage vesicles, fixation of other tissue components is usually poor. The main differences from previously reported methods using potassium permanganate are the use of a physiological saline as the vehicle for all solutions, and, following this, very rapid dehydration before infiltration with plastic. Cellular and intercellular details of tissue ultrastructure may, in general, be evaluated as satisfactorily as with conventional fixatives, with the exception of certain protein elements associated with ribosome, microtubule, and myofilament organization. Nerve endings with agranular or clear vesicles may be distinguished from adrenergic endings since the dense cores of the vesicles of the latter are preserved by this method. 相似文献
88.
Indoleamine 2,3-dioxygenase. Purification and some properties. 总被引:20,自引:0,他引:20
T Shimizu S Nomiyama F Hirata O Hayaishi 《The Journal of biological chemistry》1978,253(13):4700-4706
Indoleamine 2,3-dioxygenase was purified from rabbit small intestine to apparent homogeneity as judged by polyacrylamide gel electrophoresis and analytical ultracentrifugation. The native enzyme was a monomeric protein of a molecular weight of 41,000 +/- 1,000 with an s020,w value of 3.45 S. It had a relative abundance of hydrophobic amino acids such as valine, leucine, and isoleucine, and contained approximately 5% carbohydrate by weight. The estimated content of sugar residues per mol of enzyme was: galactose, 1.2; mannose, 2.6; N-acetylglucosamine, 5.2; and sialic acid, 0.8. One mole of enzyme had 0.8 mol of protoheme IX as a prosthetic group. However, copper was not detected in a significant amount and the ratio of copper to heme was less than 0.03. EPR spectra of the nitric oxide complex of the ferrous enzyme indicated that a nitrogen atom, possibly in an imidazole group, might be coordinated as the fifth ligand of the heme coenzyme. The anisotropic g values were gx = 2.08, gy = 1.98, and gz = 2.01. A single enzyme protein catalyzed the oxygenative ring cleavage of D- and L-tryptophan, D- and L-5-hydroxytryptophan, tryptamine, and serotonin. In addition, the purified enzyme had a peroxidase activity with guaiacol and potassium iodide as hydrogen donors, but not a catalase activity. 相似文献
89.
N Shitara P E McKeever C Cummins B H Smith P L Kornblith F Hirata 《Biochemical and biophysical research communications》1982,109(3):753-761
When C6 glioma cells were stimulated by β -adrenergic ligands, [3H]-deoxyglucose uptake by the cells decreased in the first 30 min, followed by its acceleration. The stimulation of deoxyglucose uptake was attributable to desensitization of β-adrenergic receptor-adenylate cyclase system. When the cells were treated with quinacrine or tetracaine, phospholipase inhibitors, the stimulation of deoxyglucose uptake by isoproterenol was diminished without changing the basal rate. On the other hand, when C6 glioma cells were treated with melittin or phorbol ester, phospholipase A2 activators, the deoxyglucose uptake increases even in the absence of isoproterenol. Since these compounds inhibit or enhance phospholipase A2 as well as the desensitization of β -adrenergic receptors (Proc. Natl. Acad. Sci. USA 77, 1341–1345, 1980), these results suggest that turnovers of phospholipids in the vicinity of β -adrenergic receptors modify the glucose uptake of C6 glioma cells. 相似文献
90.
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