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11.
Localization of cytochrome P-450 in the colonic mucosa of 3-methylcholanthrene-pretreated and untreated rats An immunohistochemical study 总被引:1,自引:0,他引:1
Dr. Shinji Tamura Sumio Kawata Mitsuhiro Okamoto Seiichiro Tarui 《Cell and tissue research》1988,252(2):397-401
Summary Immunohistochemical localization of cytochrome P-450 in the colonic mucosa of 3-methylcholanthrene-pretreated and untreated rats was studied by indirect fluorescent antibody staining technique. A polyclonal antibody for cytochrome P-450MC purified from hepatic microsomes of 3-methylcholanthrene-pretreated rats was used for this experiment. A strong immunofluorescence was found to be localized in the cytoplasm of the surface epithelium of the mucosa in the colon of 3-methylcholanthrene-pretreated rats. A faint immunofluorescence was also observed in the epithelium of untreated rats. 7-Ethoxycoumarin O-deethylase activity of colonic microsomes was significantly enhanced by 3-methylcholanthrene-pretreatment in parallel with an increase in the intensity of immunostaining for cytochrome P-450MC in Western blotting analysis. This is the first report on the localization of cytochrome P-450 in the colonic mucosa. 相似文献
12.
Significant differences in the thermal stability of benzodiazepine receptors were found in cerebral cortical membranes prepared from the long-sleep (LS) and short-sleep (SS) selected mouse lines. Thus, benzodiazepine receptors from LS mice were heat inactivated (55 degrees C) at a significantly faster rate than those from SS mice. Although gamma-aminobutyric acid (GABA) reduced the rate of heat inactivation in both lines, the more rapid rate of inactivation in the LS line was maintained. Furthermore, the potency of GABA to enhance [3H]flunitrazepam binding decreased threefold in membranes from LS mice as the incubation temperature was increased from 0 degrees to 37 degrees C, but was unaltered in membranes from SS mice. These differences in the biophysical properties of the benzodiazepine/GABA receptor chloride channel complex ("supramolecular complex"), together with a higher KD for t-[35S]butylbicyclophosphorothionate in membranes from LS compared to SS mice, suggest that the supramolecular complex may modulate the differential sensitivity to some depressants and convulsants in these lines. 相似文献
13.
Joseph C. Besharse 《Neurochemical research》1992,17(1):75-80
Rhythmic photoreceptor metabolism in relationship to light-dark cycles is now thought be regulated through a retinal feed-back mechanism with dopamine serving as a principal signal initiating light-evoked events. In order to test the hypothesis that depolarizing ON-bipolar neurons participate in the retinal signalling pathway, we determined the effects of L-2-amino-4-phosphonobutyrate (L-APB) on light-evoked cone contraction in eye cups fromXenopus laevis. L-APB blocked the response stereospecifically when applied over a broad concentration range. The high specificity of L-APB in retina suggests that sign-inverting bipolar neurons which depolarize in light are in the signalling pathway. One possibility is that this pathway conveys signals that regulate dopamine release.Special issue dedicated to Dr. Frederick E. Samson. 相似文献
14.
Carol Anelli Sheppard Marcia J. Loeb 《Archives of insect biochemistry and physiology》1992,21(3):179-193
A subcellular fraction enriched in plasma membranes was obtained from gypsy moth (Lymantria dispar) larval midgut tissue. Using [45Ca]2+ as a tracer, Ca2+ transport activity by membrane vesicles in the enriched fraction was measured and shown to be ATP-dependent, with a very high affinity for Ca2+ (apparent Km for [Ca2+ free] 1 Abbreviations used: [Ca2+free] = concentration of free (unbound) calcium ion;CaM = calmodulin; F = fraction; IOV = inside-out membrane vesicles; W-5 = N-(6-aminohexyl)-1-naphthalenesulfonamide; W-7 = N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide. = 22 nM). Ca2+ transport was abolished upon addition of the calcium ionophore, A23187. Ca2+-stimulated, Mg2+-dependent ATPase activity peaked between 100 and 200 nM Ca2+free. Ca2+-Mg2+-ATPase activity was inhibited by vanadate, 2 phenothiazine drugs (trifluoperazine and chlorpromazine), and the naphthalene sulfonamide, W-7; the related compound, W-5, and ouabain had a negligible effect. These results suggest the presence of a high affinity plasma membrane Ca2+ pump in gypsy moth larval midgut cells and are discussed in light of earlier work involving calcium transport in isolated midguts of larval Hyalophora cecropia. Ionic and other conditions that characterize the midgut physiology of larval Lepidoptera (e.g., luminal pH; electrochemical gradient for Ca2+; effect of certain ions and inhibitors on Ca2+ transport) contrast significantly with those found in adult Diptera. The implications that these differences may have for calcium regulation are discussed. © 1992 Wiley-Liss, Inc. 相似文献
15.
Viqar Uddin Ahmad Mohammad Ghani Shah Faryal Vali Mohammad Nargis Ismail Mushtaq Noorwala 《Phytochemistry》1991,30(12)
A new flavone glucoside macrophylloside has been isolated from the whole plant of Primula macrophylla and its structure was determined by spectroscopic methods as 2′-hydroxy-7-O-β-
-glucopyranosyloxyflavone. Sitosterol glucoside was also isolated for the first time from this plant. 相似文献
16.
Jan A. Veenstra 《Peptides》1991,12(6):1285-1289
An ELISA for corazonin, a cardioactive neuropeptide from the American cockroach, Periplaneta americana, was developed. It was used to isolate corazonin from the cockroach Nauphoeta cinerea, the locust Schistocerca americana, and the hawkmoth Manduca sexta. The peptides from Nauphoeta and Manduca had the same retention times as Periplaneta corazonin, and their amino acid compositions also suggested that these peptides are identical with corazonin. The corazonin-immunoreactive peptide from Schistocerca eluted slightly earlier on HPLC than corazonin, and its structure was determined to be [His7]corazonin, or pGlu-Thr-Phe-Gln-Tyr-Ser-His-Gly-Trp-Thr-Asn-amide. These results indicate that corazonin is generally present in insects and that its structure has been well conserved. 相似文献
17.
The activating anions are found to induce an unexpectedly high (up to 8-fold for sulphite) increase of ATPase activity in intact rat liver mitochondria. This effect is not determined by the observed changes in Km and Ki (ADP) values. The stimulation seems to be caused by dissociation of the inactive complex of ATPase with Mg·ADP. The quantity of this complex formed in the course of ATP hydrolysis is approx. 90% of the total ATPase content in intact mitochondria. The data on toluene-permeabilized mitochondria suggest that the high content of the complex is a result of the stabilizing effect of some matrix macromolecules. 相似文献
18.
W. Powell P. D. S. Caligari J. S. Swanston J. L. Jinks 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1985,71(3):461-466
Summary Random inbred lines produced by doubled haploidy (DH) and single seed descent (SSD) have been used to investigate the genetics of -glucan (gum) content in barley (Hordeum vulgare). Genetical analyses indicated that gum content is controlled by a simple additive genetic system. Significant negative genetic correlations were observed between -glucan content, thousand grain weight and height in the DH samples. These correlations were much reduced in the SSD samples and would suggest linkage of the genes controlling these characters. The presence of repulsion linkages could be exploited in a barley breeding programme by producing F1 derived DH to generate recombinants with high thousand grain weight and low -glucan content. Genetical parameters estimated from DH and F3 samples have successfully been used to predict the number of inbred lines transgressing the parental range for -glucan content and bivariate combinations involving -glucan. 相似文献
19.
Monoclonal antibody-directed immunopurification and identification of cytochromes P-450 总被引:4,自引:0,他引:4
F K Friedman R C Robinson S S Park H V Gelboin 《Biochemical and biophysical research communications》1983,116(3):859-865
A 28 amino acid peptide with diuretic and natriuretic activity has been purified from rat atrial muscle. The primary structure of this atrial peptide is H-Ser-Leu-Arg-Arg-Ser-Ser-Cys-Phe-Gly-Gly-Arg-Ile-Asp-Arg-Ile-Gly- (sequence in text) Ala-Gln-Ser-Gly-Leu-Gly-Cys-Asn-Ser-Phe-(Arg)-Tyr-OH. The biological activity of this peptide is identical to that of atrial natriuretic factor and cardionatrin I isolated from rat atria. 相似文献
20.
Chemical modification of Rhodospirillum rubrum chromatophores by 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) results in inactivation of photophosphorylation, Mg2+-ATPase, oxidative phosphorylation and ATP-driven transhydrogenase, with apparent first-order kinetics. Other energy-linked reactions such as light-driven transhydrogenase and light-dependent proton uptake were insensitive to NBD-Cl. The Ca2+-ATPase activity of the soluble coupling factor from chromatophores (R. rubrum F1) was inactivated by NBD-Cl with kinetics resembling those described for Mg2+-ATPase and photophosphorylation activities of chromatophores. Both NBD-chromatophores and NBD-R. rubrum F1 fully recovered their activities when subjected to thiolysis by dithioerythritol. Phosphoryl transfer reactions of chromatophores and Ca2+-ATPase activity of R. rubrum F1 were fully protected by 5 mM Pi against modification by NBD-Cl. ADP or ATP afforded partial protection. Analysis of the protection of Ca2+-ATPase activity by Pi indicated that NBD-Cl and Pi are mutually exclusive ligands. Spectroscopic studies revealed that tyrosine and sulfhydryl residues in R. rubrum F1 underwent modification by NBD-Cl. However, the inactivation was only related to the modification of tyrosine groups. 相似文献