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1.
Masayo Suzuki Hiroyuki Ishida Yukimasa Shiotsu Taisuke Nakata Shiro Akinaga Shigemitsu Takashima Toshiaki Utsumi Toshiaki Saeki Nobuhiro Harada 《The Journal of steroid biochemistry and molecular biology》2009,113(3-5):195-201
In order to evaluate the importance of estrogen production in tumor and surrounding tissues, we measured mRNA expression levels of 5 enzymes participating to estrogen synthesis in situ and 4 breast cancer-related proteins in 27 pairs of tumor and non-malignant tissues. Steroid sulfatase (STS) mRNA was more frequently detected in tumor tissues rather than in their non-malignant counterparts. Estrogen sulfotransferase (EST) was constantly expressed with high level not only in tumor tissues but also in their surrounding non-malignant counterparts. In contrast, mRNA expression levels of aromatase, and 17β-hydroxysteroid dehydrogenase type I and II were relatively low and detected only in small proportion of the patients. We also measured the mRNA expression levels of the same nine genes in tumor tissues of 197 breast cancer patients, and analyzed relationship between the mRNA expression level and the clinicopathological parameters. The mRNA expression levels of STS, aromatase and erbB2 in tumor tissues increased as breast cancer progressed. The tumoral mRNA expression levels of STS, estrogen receptor β, and erbB2 in patients with recurrence were higher than those in patients without recurrence. Upregulation of STS expression plays an important role in tumor progression of human breast cancer and is considered to be responsible for estrogen production in tumor and surrounding tissues. 相似文献
2.
Adenosine binding sites of rat pheochromocytoma PC 12 cell membranes: partial characterization and solubilization 总被引:1,自引:0,他引:1
Rat pheochromocytoma PC 12 cell membranes were shown to possess A2-like adenosine binding sites as assessed by using 5'-N-ethylcarboxamide[3H]adenosine [( 3H]NECA). Specific [3H]NECA binding to PC 12 cell membrane at 0 degrees C was saturable and showed a monophasic saturation profile. In contrast, [3H]NECA binding to PC 12 cell membrane at 30 degrees C exhibited a biphasic profile suggesting the presence of two specific binding site. The rank order of potency for inhibition of [3H]NECA binding at 0 degrees C was NECA greater than 2-chloroadenosine greater than 2',5'-dideoxyadenosine greater than isobutylmethylxanthine much greater than phenylisopropyladenosine. These adenosine binding sites were solubilized with sodium cholate and the solubilized portion retained the same ligand binding characteristics as those of the membrane-bound form. Gel filtration experiments indicated an apparent Stokes radius of 6.7 nm for these adenosine binding sites/detergent complexes. 相似文献
3.
Thermotropic phase behavior and stability of monosialoganglioside micelles in aqueous solution. 下载免费PDF全文
The thermotropic phase behavior of monosialoganglioside in a dilute aqueous dispersion at pH 6.8 was measured by using synchrotron radiation small-angle x-ray scattering and was analyzed by a shell-modeling method. Previous calorimetric studies on ganglioside systems have shown quite different thermotropic behaviors from other biological lipid systems, however, the details have still been ambiguous. Because of high statistical data and a shell-modeling analysis, we could elucidate the internal structural change of monosialoganglioside micelle induced by the elevation of temperature from 6 to 60 degrees C, that is, the shrinkage of the hydrophilic region and the slight expansion of the hydrophobic region occurring simultaneously, accompanying the elongation of the axial ratios of the ellipsoidal micelles. The model structures obtained explain the changes in the experimental scattering curves, the distance distribution functions, and the gyration radii. In addition we have also found an evident thermal hysteresis in the scattering curves and in the structural parameters. The present result suggests that the thickness of the hydrophilic region, namely, the conformation of oligosaccharide chains, is sensitive to a change of temperature. 相似文献
4.
The -amylase activity and ultrastructure of aleurone cells inseeds of Avena sativa L. were studied using seed halves withembryo (embryo seeds) which had imbibed water and seed halveswithout embryo (embryo-less seeds) which had imbibed water withor without GA3. -Amylase activity was detected in the aleurone layers of embryoseeds that had imbibed water and embryo-less seeds that hadimbibed GA3-water. The ultrastructure of aleurone cells withdetectable -amylase activity showed marked changes in the roughsurfaced endoplasmic reticulum (rER), in the flattened sacculesforming stacks and in the aleurone grains. The progressive changesin the rER were as follows: first, the number of slender rERincreased; then, the inner space became wider and showed roundor oval profile; and finally, the rER became slender again witha reduced number of adhering ribosomes. The flattened sacculesforming stacks were appressed to the surface of aleurone grains.With time, they decreased in number and finally disappeared.In parallel with the decrease of flattened saccules, digestionof proteinaceous material inside the aleurone grains proceeded. (Received February 24, 1987; Accepted September 3, 1987) 相似文献
5.
Thymidylate synthetase (EC 2.1.1.45) from rat regenerating liver has been purified over 5000-fold to apparent homogeneity by a procedure involving two affinity methods. Molecular weight of the native enzyme was found to be about 68,000, as determined by gel filtration. Electrophoresis in polyacrylamide gels containing sodium dodecyl sulfate yielded a single band of molecular weight of 35,000, suggesting that thymidylate synthetase is a dimer of very similar or identical subunits. The Michaelis constants for deoxyuridylate (dUMP) and (+/-)L-5,10-methylenetetrahydrofolate are 6.8 microM and 65 microM, respectively. Reaction kinetics and product inhibition studies reveal the enzymatic mechanism to be ordered sequential. 5-Fluoro-dUMP, halogenated analog of the nucleotide substrate is a competitive inhibitor of the enzyme, with an apparent Ki value of 5 nM. Amethopterin, analog of the cofactor is also a competitive inhibitor with an apparent Ki value of 23 microM. 相似文献
6.
Hiroshi Iwasaki Toshikazu Shiba Atsuo Nakata Hideo Shinagawa 《Molecular & general genetics : MGG》1989,219(1-2):328-331
Summary The ruv operon of Escherichia coli consists of two genes, orfl1 and ruv, which encode 22 and 37 kilodalton proteins, respectively, and are regulated by the SOS system. Although the distal gene, ruv, is known to be involved in DNA repair, the function of orf1 has not been studied. To examine whether orf1 is also involved in DNA repair, we constructed a strain with a deletion of the entire ruv operon. The strain was sensitive to UV even after introduction of low copy number plasmids carrying either orf1 or ruv, but UV resistance was restored by introduction of a plasmid carrying both orfl and ruv. These results suggest that orf1 as well as ruv is involved in DNA repair. Therefore, orf1 and ruv should be renamed ruvA and ruvB, respectively. 相似文献
7.
Kazuyuki Tao Kozu Makino Shuji Yonei Atsuo Nakata Hideo Shinagawa 《Molecular & general genetics : MGG》1989,218(3):371-376
Summary Treatment of Escherichia coli and Salmonella typhimurium cells with a low dose of hydrogen peroxide induces expression of a large number of genes, and confers resistance to oxidative stresses. The oxyR gene encodes a positive regulatory protein for a subset of these genes involved in the defense against oxidative damage. We cloned a DNA fragment that contains the E. coli oxyR region on a plasmid vector, and analyzed the nucleotide sequence of the gene. The amino acid sequence of OxyR protein, deduced from the nucleotide sequence, shows a high degree of homology to the sequences of a number of bacterial activator proteins including LysR, cysB, IlvY, MetR and NodD. The product of the oxyR gene identified by the maxicell procedure was a 34 kDa protein, which agrees with the size predicted from the nucleotide sequence of the gene. 相似文献
8.
9.
Systematic sequencing of the Escherichia coli genome: analysis of the 0-2.4 min region. 总被引:23,自引:7,他引:16 下载免费PDF全文
T Yura H Mori H Nagai T Nagata A Ishihama N Fujita K Isono K Mizobuchi A Nakata 《Nucleic acids research》1992,20(13):3305-3308
A contiguous 111,402-nucleotide sequence corresponding to the 0 to 2.4 min region of the E. coli chromosome was determined as a first step to complete structural analysis of the genome. The resulting sequence was used to predict open reading frames and to search for sequence similarity against the PIR protein database. A number of novel genes were found whose predicted protein sequences showed significant homology with known proteins from various organisms, including several clusters of genes similar to those involved in fatty acid metabolism in bacteria (e.g., betT, baiF) and higher organisms, iron transport (sfuA, B, C) in Serratia marcescens, and symbiotic nitrogen fixation or electron transport (fixA, B, C, X) in Azorhizobium caulinodans. In addition, several genes and IS elements that had been mapped but not sequenced (e.g., leuA, B, C, D) were identified. We estimate that about 90 genes are represented in this region of the chromosome with little spacer. 相似文献
10.
Norepinephrine(NE) release in posterior nucleus(PH) of the hypothalamus was examined before and during acute shaker (oscillation) stress in sinoaortic denervated(SAD) and sham-operated(SO) rats. NE in PH extracellular fluid of freely moving rats was collected by microdialysis and measured by sensitive radioenzymatic assay. Three days after SAD or SO operation, mean arterial pressure(MAP) and heart rate(HR) were significantly higher in SAD rats than SO rats. Baseline levels of NE in PH dialysate were also significantly elevated in SAD rats. Although five minutes of shaker stress elicited pressor and tachycardic responses coupled with increased NE release in PH of both groups, the increases in MAP and dialysate NE were larger in SAD than SO rats. These findings indicate that noradrenergic neurons in the PH respond to stress-induced stimuli and receive tonic input from baroreflex pathways. 相似文献