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排序方式: 共有638条查询结果,搜索用时 15 毫秒
61.
Nakagawa K Oak JH Higuchi O Tsuzuki T Oikawa S Otani H Mune M Cai H Miyazawa T 《Journal of lipid research》2005,46(11):2514-2524
Peroxidized phospholipid-mediated cytotoxicity is involved in the pathophysiology of diseases [i.e., an abnormal increase of phosphatidylcholine hydroperoxide (PCOOH) in plasma of type 2 diabetic patients]. The PCOOH accumulation may relate to Amadori-glycated phosphatidylethanolamine (Amadori-PE; deoxy-D-fructosyl phosphatidylethanolamine), because Amadori-PE causes oxidative stress. However, the occurrence of lipid glycation products, including Amadori-PE, in vivo is still unclear. Consequently, we developed an analysis method of Amadori-PE using a quadrupole/linear ion-trap mass spectrometer, the Applied Biosystems QTRAP. In positive ion mode, collision-induced dissociation of Amadori-PE produced a well-characterized diglyceride ion ([M+H-303]+) permitting neutral loss scanning and multiple reaction monitoring (MRM). When lipid extract from diabetic plasma was infused directly into the QTRAP, Amadori-PE molecular species could be screened out by neutral loss scanning. Interfacing liquid chromatography with QTRAP mass spectrometry enabled the separation and determination of predominant plasma Amadori-PE species with sensitivity of approximately 0.1 pmol/injection in MRM. The plasma Amadori-PE level was 0.08 mol% of total PE in healthy subjects and 0.15-0.29 mol% in diabetic patients. Furthermore, plasma Amadori-PE levels were positively correlated with PCOOH (a maker for oxidative stress). These results show the involvement between lipid glycation and lipid peroxidation in diabetes pathogenesis. 相似文献
62.
Fujita K Kobayashi K Iwamatsu A Takeuchi M Kumagai H Yamamoto K 《Archives of biochemistry and biophysics》2004,432(1):41-49
Endo-M, endo-beta-N-acetylglucosaminidase from Mucor hiemalis, is known as a useful enzyme for the synthesis of neoglycopeptides due to its transglycosylation activity. We cloned the Endo-M gene encoding a putative 744 amino acids, which shows high identity to glycoside hydrolase family 85 endo-beta-N-acetylglucosaminidases. The gene encoding Endo-M was expressed in protease-deficient Candida boidinii with a molecular mass of 85 kDa as a monomeric form. Recombinant Endo-M could liberate both high-mannose type and biantennary complex type oligosaccharides from glycopeptides, which was same as the native enzyme. The Km and Kcat values for DNS-Man6GlcNAc2Asn were 0.51 mM and 8.25 s(-1), respectively. Recombinant Endo-M also exhibited transglycosylation activity toward high-mannose type and biantennary complex type oligosaccharides, which were transferred to alcohols, monosaccharides, oligosaccharides, and glycosides. To investigate about the catalytically essential amino acids of Endo-M, site-directed mutagenesis was performed, and it was found that mutants E177G and E177Q completely abolished the hydrolytic activity and W228R partially abolished the transglycosylation activity. 相似文献
63.
Larval development and settlement of whale barnacles have not previously been described, unlike intertidal barnacles. Indeed, the mechanisms of the association between barnacles and whales have not been studied. Here we describe the larval development and settlement of the whale barnacle, Coronula diadema, and possible involvement of a cue from the host in inducing larval settlement. Eight-cell stage embryos were collected from C. diadema on a stranded humpback whale, incubated in filtered seawater for 7 days, and nauplius larvae hatched out. When fed with Chaetoceros gracilis, the nauplii developed to stage VI, and finally metamorphosed to the cypris stage. The larval development looked similar to that of intertidal barnacles with planktotrophic larval stages. The cyprids did not settle in normal seawater, but did settle in polystyrene Petri dishes when incubated in seawater with a small piece of skin tissue from the host whale. This strongly suggests the involvement of a chemical cue from the host whale tissue to induce larval settlement. 相似文献
64.
Takano H Kodama Y Kitta Y Nakamura T Obata JE Mende A Kawabata K Saitoh Y Fujioka D Kobayashi T Hasebe H Kugiyama K 《American journal of physiology. Heart and circulatory physiology》2006,291(6):H2641-H2646
Adiponectin, an adipocyte-derived protein, has been shown to have vasculoprotective effects. This study examined the possible relationship between coronary vasomotor function and the transcardiac gradient of adiponectin, reflecting adiponectin utilization and/or accumulation in the coronary vascular bed. The epicardial diameter and blood flow response of the left anterior descending coronary artery to intracoronary infusions of ACh was analyzed in 108 consecutive subjects who had a normal coronary angiogram and left ventriculogram. Adiponectin levels were measured by ELISA in plasma obtained from the aortic root (Ao) and the anterior interventricular vein (AIV). Adiponectin levels in the AIV were lower than levels in the Ao. In multivariate linear regression analysis, the transcardiac gradient of adiponectin (Ao - AIV levels) showed a positive correlation with increases in epicardial coronary diameter and coronary blood flow in response to ACh that was independent of traditional coronary risk factors. The transcardiac gradient of adiponectin was not significantly associated with the coronary dilator response to isosorbide dinitrate and the coronary flow response to sodium nitroprusside. In other groups of patients with coronary spastic angina (n = 41) or microvascular angina (n = 32) who had impaired coronary vasomotor responses, there was no significant gradient of adiponectin between the Ao and AIV. The transcardiac gradient of adiponectin may modulate endothelial vasomotor function in large and resistance coronary arteries and may play a role in the pathogenesis of diseases presenting with coronary vasomotor dysfunction. 相似文献
65.
Toshiki Watanabe Shin-ichi Kii Jiro Tanaka Kiyotaka Takishita Tadashi Maruyama 《Journal of applied phycology》2006,18(2):219-225
Three cDNAs encoding actins were identified in two culturable strains (clades A and F) of the symbiotic dinoflagellates Symbiodinium spp. In a molecular phylogenetic analysis these actin sequences formed a monophyletic group with known dinoflagellate actins, remote from Syact-p that had been isolated from a clade A Symbiodinium strain (HG39). One of the newly identified actin sequences (SyAct-F1) was the most closely related to partial actin cDNA sequences (named AGfact-p and AFcact-p) isolated from adult colonies of two reef corals (Galaxea fascicularis and Favites chinensis) that were inhabited by Symbiodinium spp., suggesting the possibility that the latter two were from the symbionts. Partial AFcact-p sequences could be amplified by PCR using genomic DNA prepared from a symbiotic adult colony of F. chinensis as the template, but not from planula larvae in which zooxanthellae could not be detected, also arguing for the origin of AFcact-p in the symbiont. An expression analysis showed that the levels of the SyAct-A1 mRNA were comparable in symbiotic and non-symbiotic states, and also in motile and non-motile phases in a cultured condition, suggesting its usefulness as a constitutively expressed control gene in expression analysis of Symbiodinium mRNAs. 相似文献
66.
Higuchi O Nakagawa K Tsuzuki T Suzuki T Oikawa S Miyazawa T 《Journal of lipid research》2006,47(5):964-974
Peroxidized phospholipid-mediated cytotoxity is involved in the pathophysiology of a number of diseases [i.e., the abnormal increase of phosphatidylcholine hydroperoxide (PCOOH) found in the plasma of type 2 diabetic patients]. The PCOOH accumulation may relate to Amadori-glycated phosphatidylethanolamine (deoxy-D-fructosyl PE, or Amadori-PE), because Amadori-PE causes oxidative stress. However, lipid glycation inhibitor has not been discovered yet because of the lack of a lipid glycation model useful for inhibitor screening. We optimized and developed a lipid glycation model considering various reaction conditions (glucose concentration, temperature, buffer type, and pH) between PE and glucose. Using the developed model, various protein glycation inhibitors (aminoguanidine, pyridoxamine, and carnosine), antioxidants (ascorbic acid, alpha-tocopherol, quercetin, and rutin), and other food compounds (L-lysine, L-cysteine, pyridoxine, pyridoxal, and pyridoxal 5'-phosphate) were evaluated for their antiglycative properties. Pyridoxal 5'-phosphate and pyridoxal (vitamin B(6) derivatives) were the most effective antiglycative compounds. These pyridoxals could easily be condensed with PE before the glucose/PE reaction occurred. Because PE-pyridoxal 5'-phosphate adduct was detectable in human red blood cells and the increased plasma Amadori-PE concentration in streptozotocin-induced diabetic rats was decreased by dietary supplementation of pyridoxal 5'-phosphate, it is likely that pyridoxal 5'-phosphate acts as a lipid glycation inhibitor in vivo, which possibly contributes to diabetes prevention. 相似文献
67.
Takishita K Tsuchiya M Reimer JD Maruyama T 《Extremophiles : life under extreme conditions》2006,10(2):165-169
The Kuroshima Knoll, located in the southern Ryukyu Arc, is known to actively bubble with gas containing methane and hydrogen sulfide from numerous fissures in the large carbonate pavement. Although ecological studies regarding macrobenthos and bacteria from Kuroshima Knoll have been intensively conducted, the community structure and ecological importance of microbial eukaryotes (protists) have not yet been investigated. In the present study, we directly extracted DNA from sediment of the Kuroshima Knoll at a depth of 640 m and constructed genetic libraries of PCR-amplified eukaryotic small-subunit ribosomal DNA (SSU rDNA). Although the SSU rDNA sequences of several types of benthic foraminifers were retrieved from the surface of the sediment, all other sequences (just below the sediment surface to approximately 9 cm below sediment surface) were derived from the basidiomycetous yeast Cryptococcus curvatus. Furthermore, sequences of the internal transcribed spacer of rDNA (ITS-rDNA) retrieved from the same sediment were identical to that of C. curvatus originating from terrestrial habitats. The diversity of microbial eukaryotes in the Kuroshima Knoll sediment seems to be extremely low and significantly different from that of other marine environments previously reported. 相似文献
68.
Gregarious settlement is essential for reproduction and survival of many barnacles. A glycoprotein, settlement-inducing protein complex (SIPC) has been recognized as a signal for settlement and it is expressed in both conspecific adults and larvae. Although the settlement-inducing activities of SIPC are species-specific, the molecular-based mechanism by which larvae distinguish conspecific SIPC from the SIPC of other species is still unknown. Here, the complete primary structure of the SIPC of Megabalanus coccopoma, as well as the partial structure of the SIPCs of Balanus improvisus, Megabalanus rosa, and Elminius modestus are reported. These SIPCs contain highly variable regions that possibly modulate the affinity for the receptor, resulting in the species specificity of SIPC. In addition, the distribution patterns of potential N-glycosylation sites were seen to be different among the various species. Differences in such post-translational modifications may contribute to the species specificity of SIPC. 相似文献
69.
Hara KY Kim S Yoshida H Kiriyama K Kondo T Okai N Ogino C Fukuda H Kondo A 《Applied microbiology and biotechnology》2012,93(4):1495-1502
Glutathione is a valuable tri-peptide that is widely used in the pharmaceutical, food, and cosmetic industries. Glutathione
is produced industrially by fermentation using Saccharomyces cerevisiae, and supplementation of fermentation with several amino acids can increase intracellular GSH content. More recently, however,
focus has been given to protein as a resource for biofuel and fine chemical production. We demonstrate that expression of
a protease on the cell surface of S. cerevisiae enables the direct use of keratin and soy protein as a source of amino acids and that these substrates enhanced intracellular
GSH content. Furthermore, fermentation using soy protein also enhanced cell concentration. GSH fermentation from keratin and
to a greater extent from soy protein using protease-displaying yeast yielded greater GSH productivity compared to GSH fermentation
with amino acid supplementation. This protease-displaying yeast is potentially applicable to a variety of processes for the
bio-production of value-added chemicals from proteinaceous biomass resources. 相似文献
70.
Ishii J Moriguchi M Hara KY Shibasaki S Fukuda H Kondo A 《Analytical biochemistry》2012,426(2):129-133
Flow cytometry enables comparative quantification, population analysis, and high-throughput screening of agonist-mediated G-protein-coupled receptor (GPCR) signaling in genetically engineered yeasts. By using flow cytometry, we found that transformation of yeast cells with a low plasmid number is critical both for the construction of large screening libraries and for stable signal transmission in cell ensembles. Based on these findings, we constructed an engineered yeast strain for the improved identification of signal promotion by Gα(i)-specific human GPCRs using flow cytometry. 相似文献