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211.
212.
213.
Desensitization of CholecystokininB Receptors in GH3 Cells 总被引:1,自引:0,他引:1
Abstract: Desensitization of the cholecystokinin (CCK) octapeptide (CCK-8)-induced rise in intracellular free calcium concentration ([Ca2+ ],) was characterized in GH3 cells, a pituitary tumor cell line, which are known to possess CCKB receptor subtype. The CCK-8-induced [Ca2+ ], transient was reduced following the initial application of CCK-8. A similar desensitization of the CCK-8-induced response was observed following the first application of thyrotropin-releasing hormone (TRH). By contrast, the TRH- induced response was not desensitized by the preceding application of CCK-8. Desensitization of the CCK-8-induced [Ca2+ ], transient was associated with diminished inositol 1,4,5-trisphosphate formation. The recovery of desensitization of the CCK-8-induced response was delayed by a phosphoserine/phosphothreonine phosphatase inhibitor, calyculin A (100 n M ). The responsiveness to CCK-8 was also reduced by phorbol 12, 13-dibutyrate (PDBu), and this effect of PDBu was completely abolished by preincubation with staurosporine. Staurosporine significantly attenuated the desensitization caused by preincubation with CCK-8, but this effect was too small to attribute the desensitization to the protein kinase C transduction pathway alone. It is likely that desensitization of CCK receptors involves multiple transduction pathways. 相似文献
214.
Yukiji Yamada Shunji Tomatsu Kazuko Sukegawa Yasuyuki Suzuki Naomi Kondo John J. Hopwood Tadao Orii 《Human genetics》1993,92(2):110-114
Southern blot analysis of the iduronate sulfatase (IDS) gene in 52 unrelated Japanese patients with mucopolysaccharidosis type II was carried out using a cDNA probe, and mutations in 13 patients (25%) were identified. Of these, 3 had partial gene deletions (in 2 the normal 9.4-kb fragment was absent and in 1 the normal 7.4-kb fragment was absent, as determined by Southern blot analysis using EcoRI-digested DNA, respectively), 2 had gene insertions (in 1 there was a unique 11.2kb fragment and in the other there was a unique 5kb fragment, determined by Southern blot analysis using EcoRI digested DNA), and 8 had rearrangements (in 6 the normal 9.4kb and 7.0kb fragments were absent and a unique 11.2kb fragment was present; in the remaining 2 patients there were different rearrangements). In these 13 patients, the similar Southern blot patterns were indicative of structural alterations of the IDS gene, as revealed when their DNA was digested with HindIII or PstI and probed with IDS cDNA. All patients with these structural alterations were in a clinically severe state, except for 1 with an intermediate clinical phenotype. Our analyses of four families among those of the 13 patients revealed that all four mothers were carriers. The detection of structural abnormalities led to a precise identification of Hunter heterozygotes and revealed one de novo rearrangement in a germ cell of one of the maternal grandparents. 相似文献
215.
Keinosuke Okamoto Yoshio Fujii Noriko Akashi Shunji Hitotsubashi Hisao Kurazono Tadahiro Karasawa Yoshifumi Takeda 《Microbiology and immunology》1993,37(5):411-414
Stock strains of Eschericia coli isolated from patients with traveller's diarrhea were examined for production of heat-stable enterotoxin II (STII). Of 400 strains examined, 3 were found to produce STII. The nucleotide sequence of the STII gene of these human strains was shown to be identical to that of porcine strains. Cultured cells of these strains induced fluid accumulation in ligated mouse intestinal loops and the activity was neutralized by anti-STII antiserum. These results suggest that STII-produciing enterotoxigenic E. coli can cause human diarrhea. 相似文献
216.
Mitsuo Masuno Shunji Tomatsu Yoshihiro Nakashima Toshinori Hori Seiji Fukuda Michiya Masue Kazuko Sukegawa Tadao Orii 《Genomics》1993,16(3)
Plasmid clones of three independent genomic fragments of the gene for human N -acetylgalactosamine-6-sulfate sulfatase (GALNS; EC 3.1.6.4) were utilized in a fluorescence in situ suppression hybridization study to assign the locus to chromosome 16q24. Enzyme assay for GALNS in a patient with del(16)(q22.1) confirmed this finding. 相似文献
217.
Novel Subtype of Peroxisomal Acyl-CoA Oxidase Deficiency and Bifunctional Enzyme Deficiency with Detectable Enzyme Protein: Identification by Means of Complementation Analysis 总被引:4,自引:1,他引:3
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Yasuyuki Suzuki Nobuyuki Shimozawa Shigehiro Yajima Shunji Tomatsu Naomi Kondo Yukikatsu Nakada Shinjiro Akaboshi Mizue Iai Yuzo Tanabe Takashi Hashimoto Ronald J. A. Wanders Ruud B. H. Schutgens Hugo W. Moser Tadao Orii 《American journal of human genetics》1994,54(1):36-43
We describe four infants with a novel subtype of an isolated deficiency of one of the peroxisomal β-oxidation enzymes with detectable enzyme protein. The patients showed characteristic clinical and biochemical abnormalities, including hypotonia, psychomotor retardation, hepatomegaly, typical facial appearance, accumulation of very-long-chain fatty acids, and decreased lignoceric acid oxidation. However, β-oxidation enzyme proteins were detected by immunoblot analyses, and large peroxisomes were identified by immunofluorescence staining. In order to identify the underlying defect in these patients, complementation analysis was introduced using fibroblasts from these patients and patients with an established deficiency of either acyl-CoA oxidase or bifunctional enzyme, as identified by immunoblotting. In the complementing combinations, fused cells showed increased lignoceric acid oxidation, resistance against 1-pyrene dodecanoic acid/UV selection, and normalization of the size and the distribution of peroxisomes. The results indicate that two patients with a more severe clinical course were suffering from bifunctional enzyme deficiency and that the other two infants, who were siblings and had a less severe clinical presentation, were the first patients with acyl-CoA oxidase deficiency with detectable enzyme protein. 相似文献
218.
Investigations on farms where botulism has occurred in cows showed that proteolytic Clostridium botulinum type B was present in newly made grass silages. Experiments were undertaken to study growth and toxin production of C. botulinum in grass. Of the strains tested only proteolytic strains of C. botulinum types A and B were able to produce toxin with grass as a substrate. Proteolytic strains of type B produced both medium (12S) and large (16S) toxin forms. The minimal water activity (aw) for toxin production at pH 6.5 and 5.8 was 0.94. At pH 5.3, toxin was produced at an aw of 0.985. These results indicate that proteolytic strains of C. botulinum (if present) may multiply and produce toxin in wilted grass silages. 相似文献
219.
Detection of three separate DNA polymorphisms in the human lipoprotein lipase gene by gene amplification and restriction endonuclease digestion. 总被引:15,自引:0,他引:15
T Gotoda N Yamada T Murase H Shimano M Shimada K Harada M Kawamura K Kozaki Y Yazaki 《Journal of lipid research》1992,33(7):1067-1072
A rapid detection method was developed for DNA polymorphisms in the human lipoprotein lipase (LPL) gene. The examined polymorphisms include an A-C transversion in the 5'-region of intron 3, a T-G transversion that occurs within a Hind III site of intron 8, and the previously described C-T transition that causes a Pvu II polymorphism in intron 6. Gene fragments encompassing each polymorphic site were amplified by the polymerase chain reaction (PCR) and digested with an appropriate restriction enzyme whose recognition site was either naturally affected by the polymorphism or artificially created with a mismatched PCR-primer. According to the digestion profiles, genotypes were unambiguously distinguished. With this method, respective allelic frequencies were determined for 50 or 70 normal subjects. The procedure will facilitate LPL genotyping in the large population. 相似文献
220.
ADP-ribosylation of the rho/rac proteins induces growth inhibition, neurite outgrowth and acetylcholine esterase in cultured PC-12 cells 总被引:12,自引:0,他引:12
T Nishiki S Narumiya N Morii M Yamamoto M Fujiwara Y Kamata G Sakaguchi S Kozaki 《Biochemical and biophysical research communications》1990,167(1):265-272
Botulinum ADP-ribosyltransferase C3 (C3 exoenzyme) was purified to homogeneity and added to cultured rat pheochromocytoma PC-12 cells. Incubation with this exoenzyme caused inhibition of cell growth and induced neurites as well as acetylcholine esterase in these cells. These changes were dependent on the amount of the enzyme added to the culture, which correlated with the in situ ADP-ribosylation of the rho/rac proteins in the cells. Preincubation with a specific anti-C3 exoenzyme monoclonal antibody inhibited both the ADP-ribosyltransferase activity and the neurite-inducing activity of the enzyme preparation. These results suggest that C3 exoenzyme affected the cellular function of the rho/rac proteins by ADP-ribosylation to induce these changes in the cells. 相似文献