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排序方式: 共有353条查询结果,搜索用时 15 毫秒
1.
Immunohistochemical localization of Na+-dependent glucose transporter in rat jejunum 总被引:2,自引:0,他引:2
Kuniaki Takata Toshiko Kasahara Michihiro Kasahara Osamu Ezaki Hiroshi Hirano 《Cell and tissue research》1992,267(1):3-9
Summary Glucose is actively absorbed via a Na+-dependent active glucose transporter (Na-GT) in the small intestine. We raised a polyclonal antibody against the peptide corresponding to amino acids 564–575 of rabbit intestinal Na-GT, and localized it immunohistochemically in the rat jejunum. By means of immunofluorescence staining, Na-GT was located at the brush border of the absorptive epithelial cells of the intestinal villi. Electron-microscopic examination showed that Na-GT was localized at the plasma membrane of the apical microvilli of these cells. Little Na-GT was found at the basolateral plasma membrane. Along the crypt-villus axis, all of the absorptive epithelial cells in the villus were positive for Na-GT. In addition to the brush border staining, the supranuclear positive staining, which was shown to be the Golgi apparatus by use of electron microscopy, was seen in cells located between the base to the middle of the villus. Cells in crypts exhibited little or no staining for Na-GT. Goblet cells scattered in the intestinal epithelium were negative for Na-GT staining. These observations show that Na-GT is specific to the apical plasma membrane of the absorptive epithelial cells, and that the onset of Na-GT synthesis may occur near the crypt-villus junction. 相似文献
2.
The distribution density of opioid receptors in the brain of El mice (seizure-susceptible strain) was examined to determine the relation between seizures and the opioid system. Saturation curves and Scatchard plots of [3H]2-d-alamine-5-d-leucine enkephalin binding revealed that the opioid delta receptor density in adult El mice during interictal periods was significantly increased in the cerebral cortex, hippocampus, and septal area. It was further shown that the concentration of such receptors in 25-day-old El mice that had no seizures was also significantly increased in the hippocampus and septal area, with no changes in apparent affinities, as compared with in the corresponding regions in ddY mice (seizure-nonsusceptible strain; the mother strain of El). Such up-regulation of opioid receptors in the El mouse brain could result from deficits in endogenous opioid peptides, which could be associated with the pathogenesis of seizure diathesis in the El mouse. 相似文献
3.
Furukawa Toshiko; Koga Jinichiro; Adachi Takashi; Kishi Kunihei; Syono Kunihiko 《Plant & cell physiology》1996,37(7):899-905
In a study of various phytopathogenic fungi, we found that fungithat belong to the genus Rhizoctonia produce IAA efficientlyfrom tryptophan. R. solani Kühn MAFF-305219, in particular,produced large amounts of tryptophol (Tol), which was assumedto be a specific by-product of the indole-3-pyruvate (IPy) pathway,in addition to IAA. Therefore, this fungus seemed suitable foranalysis of the function and the regulation of the biosynthesisof auxin by a fungal pathogen. Under normal aerobic conditions,the ratio of IAA to Tol synthesized by this strain was higherthan that under less aerobic conditions. In metabolic studieswith various indole derivatives, R. solani converted L-tryptophanand indole-3-acetaldehyde to IAA and Tol, but other indole derivativeswere scarcely metabolized. These results suggest that both IAAand Tol are synthesized from tryptophan through the IPy pathwayin Rhizoctonia. (Received May 27, 1996; Accepted July 8, 1996) 相似文献
4.
Expression of NADH-Dependent Glutamate Synthase in Response to the Supply of Nitrogen in Rice Cells in Suspension Culture 总被引:2,自引:0,他引:2
Watanabe Sachiko; Sakai Takahiro; Goto Satoshi; Yaginuma Toshiko; Hayakawa Toshihiko; Yamaya Tomoyuki 《Plant & cell physiology》1996,37(7):1034-1037
The effects of inorganic and organic nitrogen on the levelsof mRNA for NADH-dependent glutamate synthase (GOGAT) and theprotein were examined in rice cells in suspension culture. Asupply of NH+4, NO-3, glutamine, or asparagine induced the accumulationof the protein and mRNA, but levels of mRNA for ferredoxin-GOGATwere hardly affected.
1Present address: P.C. Center Wakuya-cho, Toda-gun, Miyagi,Japan. 相似文献
5.
Toshiko Yamamoto Saburo Yamamoto Tetsuro Kataoka Tohru Tokunaga 《Microbiology and immunology》1994,38(10):831-836
A synthetic 22-mer oligodeoxyribonucleotide having an AACGTT palindrome, AAC-22, induced interferon (IFN) production and augmented the natural killer (NK) activity in murine splenocytes, whereas its analogue, ACC-22, having an ACCGGT palindrome, did not. The binding of AAC-22 to splenocytes was not different from that of ACC-22. Lipofection of AAC-22 to splenocytes remarkably enhanced IFN production and NK cell activity, whereas that of ACC-22 caused little enhancement. These results strongly suggest that the prerequisite for IFN production is not the binding of AAC-22 to the cell surface receptors, but its penetration into the spleen cells. 相似文献
6.
Masafumi Tomita Toshiko Okuyama Shoichi Sato Hideo Ishizu 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1993,621(2)
We applied micellar electrokinetic capillary chromatography to simultaneous separation and determination of nitrazepam and its major metabolites, 7-aminonitrazepam and 7-acetamidonitrazepam, in spiked urine. Prior to electrophoresis, the three compounds were successfully extracted from the spiked urine with commercial disposable solid-phase cartridges. The optimum running buffer for the separation was prepared by combining 85 parts of 60 mM sodium dodecyl sulphate—6 mM phosphate—borate, adjusted to pH 8.5, with 15 parts of methanol. The separation order, completed within 25 min, was 7-aminonitrazepam > 7-acetamidonitrazepam > nitrazepam, at an applied potential of 20 kV. We obtained reproducible electropherograms in successive repetitions, and few other peaks or interferences appeared in the electropherogram. The detection limits of the three compounds were 50–100 pg (0.1–0.2 μg/ml of analyte in spiked urine), and the recoveries were 78.9–100.8% for 1 μg/ml and 84.1–100.3% for 5 μg/ml. The application of this method to forensic or clinical samples is demonstrated. 相似文献
7.
Akihiro Yoshida Kuniaki Takata Toshiko Kasahara Toshio Aoyagi Shozo Saito Hiroshi Hirano 《The Histochemical journal》1995,27(5):420-426
Summary Glucose is actively absorbed in the intestine by the action of the Na+-dependent glucose transporter. Using an antibody against the rabbit intestinal Na+-dependent glucose transporter (SGLT1), we examined the localization of SGLT1 immunohistochemically along the rat digestive
tract (oesophagus, stomach, duodenum, jejunum, ileum, colon and rectum). SGLT1 was detected in the small intestine (duodenum,
jejunum and ileum), but not in the oesophagus, stomach, colon or rectum. SGLT1 was localized at the brush border of the absorptive
epithelium cells in the small intestine. Electron microscopical examination showed that SGLT1 was localized at the apical
plasma membrane of the absorptive epithelial cells. SGLT1 was not detected at the basolateral plasma membrane. Along the crypt-villus
axis, all the absorptive epithelial cells in the villus were positive for SGLT1, whose amount increased from the bottom of
the villus to its tip. On the other hand, cells in the crypts exhibited little or no staining for SGLT1. Goblet cells scattered
throughout the intestinal epithelium were negative for SGLT1. These observations show that SGLT1 is specific to the apical
plasma membrane of differentiated absorptive epithelial cells in the small intestine, and suggest that active uptake of glucose
occurs mainly in the absorptive epithelial cells in the small intestine. 相似文献
8.
The reactivities of anionic nitroalkanes with 2-nitropropane dioxygenase of Hansenula mrakii, glucose oxidase of Aspergillus niger, and mammalian d-amino acid oxidase have been compared kinetically. 2-Nitropropane dioxygenase is 1200 and 4800 times more active with anionic 2-nitropropane than d-amino acid oxidase and glucose oxidase, respectively. The apparent Km values for anionic 2-nitropropane are as follows: 2-nitropropane dioxygenase, 1.61 mm; glucose oxidase, 16.7 mm; and d-amino acid oxidase, 11.1 mm. Anionic 2-nitropropane undergoes an oxygenase reaction with 2-nitropropane dioxygenase and glucose oxidase, and an oxidase reaction with d-amino acid oxidase. In contrast, anionic nitroethane is oxidized through an oxygenase reaction by 2-nitropropane dioxygenase, and through an oxidase reaction by glucose oxidase. All nitroalkane oxidations by these three flavoenzymes are inhibited by Cu and Zn-superoxide dismutase of bovine blood, Mn-superoxide dismutases of bacilli, Fe-superoxide dismutase of Serratia marcescens, and other scavengers such as cytochrome c and NADH, but are not affected by hydroxyl radical scavengers such as mannitol. None of the scavengers tested affected the inherent substrate oxidation by glucose oxidase and d-amino acid oxidase. Furthermore, the generation of in the oxidation of anionic 2-nitropropane by 2-nitropropane dioxygenase was revealed by ESR spectroscoy. The ESR spectrum of anionic 2-nitropropane plus 2-nitropropane dioxygenase shows signals at g1 = 2.007 and g11 = 2.051, which are characteristic of . The generated is a catalytically essential intermediate in the oxidation of anionic nitroalkanes by the enzymes. 相似文献
9.
Fructose as a carbohydrate source yields stable pH and redox parameters in microcarrier cell culture
Toshiko Imamura Charles L. Crespi William G. Thilly Henri Brunengraber 《Analytical biochemistry》1982,124(2):353-358
The pH and cytosolic NADH/NAD+ redox potential in microcarrier cultures of Madin-Darby canine kidney cells remain within physiological range when fructose is substituted for glucose in medium formulation. This difference is accounted for by the low rate of lactic acid production in cultures utilizing fructose as a primary carbohydrate source. 相似文献
10.
Showdomycin inhibited pig brain ( with pseudo first-order kinetics. The rate of inhibition by showdomycin was examined in the presence of 16 combinations of four ligands, i.e., Na+, K+, Mg2+ and ATP, and was found to depend on the ligands added. Combinations of ligands were divided into five groups in terms of the magnitude of the rate constant; in the order of decreasing rate constants these were: (1), (2) , , and none, (3) , and , (4) and , , , and ATP. The highest rate was obtained in the presence of Na+, Mg2+ and ATP. The apparent concentrations of Na+, Mg2+ and ATP for half-maximum stimulation of inhibition () were 3 mM, 0.13 mM and 4μM, respectively. The rate was unchanged upon further increase in Na+ concentration from 140 to 1000 mM. The rates of inhibition could be explained on the basis of the enzyme forms present, including E1, E2, ES, E1-P and E2-P, i.e., E2 has higher reactivity with showdomycin than E1, while E2-P has almost the same reactivity as E1-P. We conclude that the reaction of ( proceeds via at least four kinds of enzyme form (E1, E2, E1 · nucleotide and EP), which all have different conformations. 相似文献