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排序方式: 共有182条查询结果,搜索用时 15 毫秒
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2.
Hideya Hayashi Seiji Ito Teruo Tanaka Manabu Negishi Hideo Kawabe Yokohama Hiromitsu Kikuko Watanabe Osamu Hayaishi 《Prostaglandins & other lipid mediators》1987,33(4)
In view of the recent finding that prostaglandin D2 is stereospecifically converted to 9α,11β-prostaglandin F2, an isomer of prostaglandin F2α, a highly specific and sensitive radioimmunoassay for 9α,11β-prostaglandin F2 was developed and applied to determine the content of this prostaglandin in various rat tissues. Antisera against 9α-11β-prostaglandin F2 were raised in rabbits immunized with the bovine serum albumin conjugate, and [3H]9α,11β-prostaglandin F2 was enzymatically prepared from [3H]prostaglandin D2. The assay detected 9α,11β-prostaglandin F2 over the range of 20 pg to 1 ng, and the antiserum showed less than 0.04% cross-section with prostaglandin F2α, prostaglandin F2β and 9β,11β-prostaglandin F2. To avoid postmortem changes, tissues were frozen in liquid nitrogen immediately after removal. The basal level of 9α,11β-prostaglandin F2 was hardly detectable in various tissues of the rat examined, including spleen, lung, liver and brain; although it was found to be 0.31 ± 0.06 ng/g wet weight in the small intestine. During convulsion induced by pentylenetetrazole, enormous amounts of prostaglandin D2 (ca. 180 ng/g wet weight) and prostaglandin F2α (ca. 70 ng/g) were produced in the brain; however, 9α,11β-prostaglandin F2 was detected neither there nor in the blood. This result demonstrates that the conversion to 9α,11β-prostaglandin F2 is a minor pathway, if one at all, of prostaglandin D2 metabolism in the rat brain. 相似文献
3.
Purification and properties of pyridine nucleotide-independent L-lactate dehydrogenase from Polyporus circinatus 总被引:1,自引:1,他引:0 下载免费PDF全文
Cell extracts of Polyporus circinatus grown on lactate catalyze the reduction of 2,6-dichlorophenolindophenol by l-lactate without the participation of nicotinamide adenine dinucleotide or nicotinamide adenine dinucleotide phosphate. The enzyme has been purified 78-fold and was homogenous by disc gel electrophoresis. The optimal pH was found to be 6.7. The Michaelis constant for l-lactate was 5.9 x 10(-4) M and the oxalate inhibition constant was 1.5 x 10(-4) M. The nature of the prosthetic group is discussed. 相似文献
4.
5.
Nucleotide sequence and characterization of the traABCD region of IncI1 plasmid R64. 总被引:2,自引:2,他引:0 下载免费PDF全文
A 3.6-kb BglII-SmaI segment of the transfer region of IncI1 plasmid R64drd-11 was sequenced and characterized. Analysis of the DNA sequence indicated the presence of four genes, traA, traB, traC, and traD, in this region. The expression of the traB, traC, and traD genes was examined by maxicell experiments and that of the traA gene was examined by constructing the traA-lacZ fusion gene. The introduction of frameshift mutations into the four genes indicated that the traB and traC genes are essential for conjugal transfer in liquid medium and on a solid surface. Both were also required for the formation of the thin pilus, which is the receptor for phages I alpha and PR64FS. Upstream of the traA gene, a promoter sequence for sigma 70 of E. coli RNA polymerase was identified by S1 nuclease mapping and primer extension experiments. 相似文献
6.
Extracellular matrix components of the placental extravillous trophoblast: immunocytochemistry and ultrastructural distribution 总被引:7,自引:0,他引:7
B. Huppertz S. Kertschanska H. -G. Frank G. Gaus H. Funayama P. Kaufmann 《Histochemistry and cell biology》1996,106(3):291-301
Invasive extravillous trophoblast cells of the human placenta are embedded in a self-secreted extracellular matrix, the matrix-type
fibrinoid. The ultrastructure and molecular composition of the matrix-type fibrinoid of the term human placenta were studied
by transmission electron microscopy and immunogold labelling. We used antibodies directed against different matrix proteins
such as collagen type IV, laminin, vitronectin, heparan sulfate, various fibronectin isoforms, and against the oncofetal blood
group antigen, ”i”. Immunogold labelling patterns of matrix proteins are the basis for the subdivision of the trophoblast-derived
matrix-type fibrinoid into mosaic-like patches of structurally and immunocytochemically different compartments. Firstly, fine
granular patches with structural similarities to basal lamina material are composed solely of collagen type IV and laminin.
Secondly, an ultrastructurally amorphous glossy substance shows reactivity with antibodies against heparan sulfate and vitronectin.
A third type of patches, fine fibrillar networks embedded in the above-mentioned glossy matrix, are reactive with antibodies
against normal fibronectin isoforms (IST-4, IST-6, IST-9) and oncofetal isoforms (BC-1, FDC-6). The blood group precursor
antigen ”i” was not only expressed on the surfaces of the extravillous trophoblast cells but was associated with the fibronectin-positive
fibrils. In conclusion, within this extracellular matrix, clear compartments of different composition can be distinguished
from each other. Glycosylation with ”i” in this matrix may be involved in immunological masking, thus preventing rejection
of placenta and fetus.
Accepted: 6 May 1996 相似文献
7.
E M Benelli E M Souza S Funayama L U Rigo F O Pedrosa 《Journal of bacteriology》1997,179(14):4623-4626
Two glnB-like genes have been isolated from Herbaspirillum seropedicae by complementation of the Klebsiella pneumoniae glnB502 mutant for growth on nitrate. One of these glnB-like genes has been sequenced and shows strong identity with GlnB proteins derived from other organisms. A Tn5-20 mutation of this glnB was Nif negative. 相似文献
8.
Funayama N Nakatsukasa M Kuraku S Takechi K Dohi M Iwabe N Miyata T Agata K 《Zoological science》2005,22(10):1113-1122
Sponges (phylum Porifera) have remarkable regenerative and reconstitutive abilities and represent evolutionarily the oldest metazoans. To investigate sponge stem cell differentiation, we have focused on the asexual reproductive system in the freshwater sponge Ephydatia fluviatilis. During germination, thousands of stem cells proliferate and differentiate to form a fully functional sponge. As an initial step of our investigation of stem cell (archeocyte) differentiation, we isolated molecular markers for two differentiated cell types: spicule-making sclerocyte cells, and cells involved in innate immunity. Sclerocyte lineage-specific Ef silicatein shares 45% to 62% identity with other sponge silicateins. As in situ hybridization of Ef silicatein specifically detects archeocytes possibly committed to sclerocytes, as well as sclerocytes with an immature or mature spicule, therefore covering all the developmental stages, we conclude that Ef silicatein is a suitable sclerocyte lineage marker. Ef lectin, a marker for the cell type involved in innate immunity, shares 59% to 65% identity with the marine sponge Suberites domuncula galactose-binding protein (Sd GBP) and horseshoe crab Tachypleus tridentatus tachylectin1/lectinL6. Since Sd GBP and tachylectin1 are known to bind to bacterial lipopolysaccharides and inhibit the growth of bacteria, Ef lectin may have a similar function and be expressed in a specialized type of cell involved in defense against invading bacteria. Ef lectin mRNA and protein are not expressed in early stages of development, but are detected in late stages. Therefore, Ef lectin may be specifically expressed in differentiating and/or differentiated cells. We suggest Ef lectin as a marker for cells that assume innate immunity in freshwater sponges. 相似文献
9.
Hatazawa R Tanaka A Tanigami M Amagase K Kato S Ashida Y Takeuchi K 《American journal of physiology. Gastrointestinal and liver physiology》2007,293(4):G788-G797
We examined the involvement of cyclooxygenase (COX)-1 as well as COX-2 in the healing of gastric ulcers and investigated which prostaglandin (PG) EP receptor subtype is responsible for the healing-promoting action of PGE2. Male SD rats and C57BL/6 mice, including wild-type, COX-1(-/-), and COX-2(-/-), were used. Gastric ulcers were produced by thermocauterization under ether anesthesia. Gastric ulcer healing was significantly delayed in both rats and mice by indomethacin and rofecoxib but not SC-560 given for 14 days after ulceration. The impaired healing was also observed in COX-2(-/-) but not COX-1(-/-) mice. Mucosal PGE2 content increased after ulceration, and this response was significantly suppressed by indomethacin and rofecoxib but not SC-560. The delayed healing in mice caused by indomethacin was significantly reversed by the coadministration of 11-deoxy-PGE1 (EP3/EP4 agonist) but not other prostanoids, including the EP1, EP2, and EP3 agonists. By contrast, CJ-42794 (selective EP(4) antagonist) significantly delayed the ulcer healing in rats and mice. VEGF expression and angiogenesis were both upregulated in the ulcerated mucosa, and these responses were suppressed by indomethacin, rofocoxib, and CJ-42794. The expression of VEGF in primary rat gastric fibroblasts was increased by PGE2 or AE1-329 (EP4 agonist), and these responses were both attenuated by coadministration of CJ-42794. These results confirmed the importance of COX-2/PGE2 in the healing mechanism of gastric ulcers and further suggested that the healing-promoting action of PGE2 is mediated by the activation of EP4 receptors and is associated with VEGF expression. 相似文献
10.
G K Funayama 《Revista brasileira de biologia》1973,33(4):581-588