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排序方式: 共有676条查询结果,搜索用时 268 毫秒
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Gene expression analysis of zebrafish heart regeneration 总被引:1,自引:0,他引:1
66.
Brian J. Hawkins Krishna M. Irrinki Karthik Mallilankaraman Yu-Chin Lien Youjun Wang Cunnigaiper D. Bhanumathy Ramasamy Subbiah Michael F. Ritchie Jonathan Soboloff Yoshihiro Baba Tomohiro Kurosaki Suresh K. Joseph Donald L. Gill Muniswamy Madesh 《The Journal of cell biology》2010,190(3):391-405
Oxidant stress influences many cellular processes, including cell growth, differentiation, and cell death. A well-recognized link between these processes and oxidant stress is via alterations in Ca2+ signaling. However, precisely how oxidants influence Ca2+ signaling remains unclear. Oxidant stress led to a phenotypic shift in Ca2+ mobilization from an oscillatory to a sustained elevated pattern via calcium release–activated calcium (CRAC)–mediated capacitive Ca2+ entry, and stromal interaction molecule 1 (STIM1)– and Orai1-deficient cells are resistant to oxidant stress. Functionally, oxidant-induced Ca2+ entry alters mitochondrial Ca2+ handling and bioenergetics and triggers cell death. STIM1 is S-glutathionylated at cysteine 56 in response to oxidant stress and evokes constitutive Ca2+ entry independent of intracellular Ca2+ stores. These experiments reveal that cysteine 56 is a sensor for oxidant-dependent activation of STIM1 and demonstrate a molecular link between oxidant stress and Ca2+ signaling via the CRAC channel. 相似文献
67.
Jianmin Meng Egil Lien Douglas T. Golenbock 《The Journal of biological chemistry》2010,285(12):8695-8702
Lipopolysaccharide (LPS) activates innate immune responses through TLR4·MD-2. LPS binds to the MD-2 hydrophobic pocket and bridges the dimerization of two TLR4·MD-2 complexes to activate intracellular signaling. However, exactly how lipid A, the endotoxic moiety of LPS, activates myeloid lineage cells remains unknown. Lipid IVA, a tetra-acylated lipid A precursor, has been used widely as a model for lipid A activation. For unknown reasons, lipid IVA activates proinflammatory responses in rodent cells but inhibits the activity of LPS in human cells. Using stable TLR4-expressing cell lines and purified monomeric MD-2, as well as MD-2-deficient bone marrow-derived macrophages, we found that both mouse TLR4 and mouse MD-2 are required for lipid IVA activation. Computational studies suggested that unique ionic interactions exist between lipid IVA and TLR4 at the dimerization interface in the mouse complex only. The negatively charged 4′-phosphate on lipid IVA interacts with two positively charged residues on the opposing mouse, but not human, TLR4 (Lys367 and Arg434) at the dimerization interface. When replaced with their negatively charged human counterparts Glu369 and Gln436, mouse TLR4 was no longer responsive to lipid IVA. In contrast, human TLR4 gained lipid IVA responsiveness when ionic interactions were enabled by charge reversal at the dimerization interface, defining the basis of lipid IVA species specificity. Thus, using lipid IVA as a selective lipid A agonist, we successfully decoupled and coupled two sequential events required for intracellular signaling: receptor engagement and dimerization, underscoring the functional role of ionic interactions in receptor activation. 相似文献
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Antihyperglycemic effect of polysaccharide from fermented broth of Pleurotus citrinopileatus 总被引:2,自引:0,他引:2
Pleurotus citrinopileatus is an edible mushroom, which has recently become very popular, with a consequent increase in industrial production. Water-soluble
polysaccharides (WSPS), extracted from edible mushrooms, have been found to have antitumor and immunoenhancing effects. In
this study, we investigate the effects of WSPS extracted from submerged fermented medium of P. citrinopileatus on hyperglycemia and damaged pancreatic cells in rats with streptozotocin (STZ)-induced diabetes. The diabetic rats fed with
water-soluble polysaccharide of P. citrinopileatus (SPPC) lost less body weight than those fed SPPC-free regular diet. Serum total cholesterol and triglyceride levels in the
diabetic rats fed with SPPC at a dose of 0.4 g/kg bw daily was lower than in the groups fed with SPPC at doses of 0.04 and
0.12 g/kg bw. The fasting blood glucose levels of diabetic rats fed with SPPC were 44% lower than the negative controls. The
degree of damage to the islets of Langerhans of the rats fed with the highest dosage of SPPC was significantly lower than
those fed with SPPC at doses of 0.04 and 0.12 g/kg bw. The results showed that STZ-induced diabetic rats fed with SPPC might
help alleviate the elevation of the level of that in fasting blood glucose. 相似文献
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Insect seed predation may vary depending on seed production. The present study considers the hypothesis that the rates of seed predation tend to be smaller in years of higher fruit production. Thus, we monitored the production of fruits and predation of seeds of the palm Syagrus romanzoffiana over 2?years in the Atlantic Forest (Parque Municipal da Lagoa do Peri, Florianópolis, SC, Brazil), between July 2006 and June 2008. Plots of 0.25?m2 were fitted under 20 mother plants and fruits were monthly collected for assessment of abundance and seed predation. There was variation in fruit production between the 2?years and among reproductive plants. Predation rates were high and occurred in the predispersal phase by the Curculionidae Revena rubiginosa Boheman, Anchylorhynchus aegrotus Fahraeus, and Anchylorhynchus variabilis Gyllenhal. Seed predation by these species of Anchylorhynchus is first registered in the present study. In average, about 60% of the seeds monthly produced in the population tend to escape insect predation in year of high or low production, becoming available for recruitment. The predation rate was not related to the amount of fruits produced per reproductive plant. Also, different than expected, there was a positive relation between the rates of seed predation and the total of fruits produced monthly on the plots. Thus, no evidence for the satiation of insect seed predators was found in this study with S. romanzoffiana. 相似文献