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排序方式: 共有198条查询结果,搜索用时 0 毫秒
1.
Kunio Yonemasu Takako Sasaki Yoshiko Dohi Charles M. Lapière Betty Nusgens 《生物化学与生物物理学报:疾病的分子基础》1990,1096(1):47-51
C1q, a collagen-like complement protein, was purified from the serum of a ddermatosparactic calf which lacks procollagen N-terminal proteinase (pN-proteinase). The specific hemolytic activity of the serum Clq from the dermatosparactic animal was identical to that of C1q from a normal calf. Gel-filtration of serum from dermatosparactic calf, on Sepharose 6B, showed the presence of C1q-antigenic material at only one position which was identical to the elution position of normal bovine C1q. No differdence, under dissociating conditions, could be seen in the size of the chains of C1q in specific immunoprecipitates isolated from the sera of dermatosparactic and normal animals, as judged by polyacrylamidegel electrophoresis (PAGE) in the presence of sodium dodecyl sulfate (SDS). The C1q from the dermatosparactic animal showed the same N-terminal amino acid and typtic-digest peptide pattern on HPLC as C1q from the normal calf. These results strongly suggest that pN-proteinase is not involved in the extracellular processing of C1q. 相似文献
2.
A mycolic acid-containing glycolipid, trehalose 2,3,6'-trimycolate, prepared from a non-pathogenic acid-fast bacterium Gordona aurantiaca, was shown to induce strong tumoricidal activity in peritoneal exudate cells by intravenous or intraperitoneal injection of liposome-encapsulated preparations. The mycolic acid derivative containing a high proportion of unsaturated fatty acids rendered macrophages cytotoxic against syngeneic mastocytoma cells in the absence of endotoxin, for over 14 days after the injection. The macrophages were ascertained to be at low intracellular levels of a lysosomal enzyme beta-galactosidase and an ectoenzyme alkaline phosphodiesterase, a specific pattern as previously described for "primed macrophages". However the culture supernatants of the peritoneal exudate cells were not cytotoxic. 相似文献
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A peptide fragment Fr. 17 (Lys1-Cys-Asn27 Leu129-Cys-Ala122) of hen egg white lysozyme (HL) was previously found to retain at least one antigenic determinant region of the native protein. In this work a highly purified preparation of Fr. 17, contaminated with less than 0.01% HL and less than 1% of other fragments was found to be strongly immunogenic to rabbits. The kinetic patterns of antibody formation against Fr.17, assayed by passive hemagglutination (PHA), were quite different from those of antibody formation against HL. The specificity of the antibody elicited to Fr. 17 was mainly directed to the Fr. 9-10-a region (Ala11-Asn27) while that of the antibody elicited to the Fr. 17 region in native HL was directed to the Fr. 15-b region (Lys1-Cys-Ala10 Leu129-Cys-Trp123). It is concluded that in the process of antibody formation, the recognition of the Fr. 17 region in native HL is different from that of fragment Fr. 17. 相似文献
5.
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
6.
Time-dependent changes in peptide transport system (PTS-6), which transports the 38 amino acid pituitary adenylate cyclase activating polypeptide (PACAP) across the blood-brain barrier (BBB) and blood-spinal cord barrier (BSCB), were studied in mice in a cardiac arrest model. The permeability of the BSCB to radioactivity labeled I131 showed a reversible increase on Day 2-(24 h) after cardiac arrest. The BBB showed no such increase. The increase in BSCB permeability was primarily located within the thoracic region of the spinal cord. We conclude that the ischemia occurring with cardiac arrest results in a transient increase in PTS-6 activity located primarily in the thoracic region of the spinal cord. 相似文献
7.
Atsushi Hayakawa Kazuo Kuwata Seiichi Era Masaru Sogami Hiroyuki Shimonaka Michio Yamamoto Shuji Dohi Hajime Hirose 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1997,698(1-2)
Human serum albumin is a mixture of mercapt- (HMA, reduced form) and nonmercaptalbumin (HNA, oxidized form). We studied the mercapt↔nonmercapt conversion of human serum albumin, which reflects the redox state of the extracellular fluids, in cardiac and other common surgical patients using high-performance liquid chromatography. Mean values of [(HMA)/(HMA + HNA)] ± standard deviation [fHMA ± σ], for patients who received common surgery (group 1) and cardiac surgery (group 2) at the start of anesthesia were0.636±0.50(n=83) and 0.615±0.062(n=14), respectively. fHMA values were markedly lower than those for healthy male adults of 0.750±0.028(n=28). fHMA values increased at 24 h after the start of anesthesia and decreased on the 4th postoperative day in most of the patients. These postoperative changes were prominent in surgical cardiac patients. Although fHMA values after the 7th postoperative day recovered to those at the start of anesthesia in almost all of common surgical patients, those in cardiac surgical patients, never recovered even on the 21st postoperative day. 相似文献
8.
Enhancement of Stimulation-Evoked Catecholamine Release from Cultured Bovine Adrenal Chromaffin Cells by Forskolin 总被引:7,自引:9,他引:7
Katsuya Morita Toshihiro Dohi Shigeo Kitayama Yutaka Koyama Akira Tsujimoto 《Journal of neurochemistry》1987,48(1):243-247
Acetylcholine (ACh) increased cyclic AMP levels in cultured bovine chromaffin cells with a peak effect at 1 min after the addition. Pretreatment with forskolin (0.3 microM) enhanced the ACh-evoked cyclic AMP increase. The catecholamine (CA) release induced by ACh was enhanced by forskolin, but forskolin alone did not enhance the CA release. The effect of forskolin increased dose-dependently up to 1 microM, but decreased at higher concentrations. Dibutyryl cyclic AMP (DBcAMP) also enhanced ACh-evoked CA release, but the effect was less potent than that of forskolin. Forskolin enhanced both [3H]norepinephrine ([3H]NE) and endogenous CA release evoked by 30 mM K+ from cells that were preloaded with [3H]NE. The effects of forskolin were substantial when CA release was evoked with low concentrations of ACh or excess K+, but decreased with higher concentrations of the stimulants. Forskolin also enhanced the CA release induced by ionomycin and veratrine, or by caffeine in Ca2+-free medium. The potentiation by forskolin of the ACh-evoked CA release was manifest in low Ca2+ concentrations in the medium, but decreased when Ca2+ concentration was increased. These results suggest that cyclic AMP may play a role in the modulation of CA release from chromaffin cells. 相似文献
9.
An in vitro system for the synthesis of ornithine transcarbamylase (OTCase) was established using iS-30 extract from E. coli MDS6-2(lambda) and DNA of a lambda transducing phage carrying argI and argF genes. This in vitro synthesis was completely dependent on the additon of DNA, and was sensitive to chloramphenicol and rifampicin. Radioisotopic analysis confirmed that the synthesized enzyme catalyzes the carbamylation of ornithine to citrulline. In the in vitro system the repression and derepression of OTCase synthesis could be observed by mixing iS-30 extracts prepared from argR+ and argR- cells. A remarkable maturation effect could be observed for the FFF enzyme, but not for the III enzyme. This system is considered to reflect the in vivo situation, and should therefore be useful for investigations on the regulation of OTCase synthesis in vivo. 相似文献
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