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1-甲基环丙烯和温度对桃和油桃贮藏品质的影响 总被引:19,自引:0,他引:19
以‘秦光2 号’油桃和‘秦王’桃为试材, 在0 ℃和5 ℃两种贮藏温度条件下研究了1-甲基环丙烯(1-MCP) 对果实呼吸速率、乙烯释放速率、硬度、可滴定酸含量、可溶性固形物含量及果肉褐变的影响。结果表明, 0 ℃的贮藏温度能显著降低秦光2号油桃和秦王桃的呼吸速率和乙烯释放速率, 减缓果实软化。1μL·L -1的1-MCP 处理能降低果实的呼吸速率和乙烯释放速率, 抑制果实软化, 减少果肉褐变,但对可滴定酸和可溶性固形物含量无明显影响。 相似文献
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AIM: To evaluate the alterations in calcium metabolism of the vascular smooth muscle in the late phase of septic shock and test the hypothesis that nitric oxide might be involved in sepsis-induced vascular hyporeactivity. METHODS: Male Sprague-Dawley rats were subjected to sepsis by cecal ligation and puncture (CLP). 18 hours post CLP, rat aortic rings were employed for measurement of contractile responses by using organ bath technique. RESULTS: In endothelium-denuded aortic rings from CLP rats, concentration-contraction curves to phenylephrine (PE) and KCl were significantly decreased when compared to that from sham control rats. The transient contraction induced by PE in calcium-free Krebs solution and the concentration-dependent contraction to CaCl2 in KCl-depolarized medium were also markedly reduced. The hyporeactivity was partially reversed by treatment with aminoguanidine, a selective inducible nitric oxide synthase inhibitor. CONCLUSION: An impairment in calcium handling in vascular smooth muscle is involved in the vascular hyporeactivity during the late phase of septic shock, in which an excessive nitric oxide production might be the major mechanism. 相似文献
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九种李属植物的RAPD亲缘关系分析 总被引:21,自引:0,他引:21
以李属植物9 个种的20 个材料为研究对象, 用RAPD技术对其进行亲缘关系分析。在建立适合李属植物的PCR2RAPD反应体系的基础上, 从45 个随机引物(10 mer) 中筛选出24 个, 对所有供试材料进行扩增, 共获得24 张DNA 指纹图谱, 326 条DNA 谱带, 其中有311 条为多态带。建立了基于RAPD 的李属植物亲缘关系树形图, 树形图的聚类结果与经典的李属植物的起源、分布和分类基本一致。另外, 根据聚类结果, 作者认为: 1) 乌苏里李是中国李的一个变种而非一独立的种; 2) 杏李是一李杏杂种且与杏有较近的亲缘关系; 3) 从分子水平证明了欧洲李(Prunus domestica L. ) 是由樱桃李(P. cerasifera Ehrh. ) 和黑刺李(P. spinosa L. ) 自然杂交形成的后代。 相似文献
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Li M Liang CG Xiong B Xu BZ Lin SL Hou Y Chen DY Schatten H Sun QY 《Domestic animal endocrinology》2008,34(4):360-371
Previous studies have shown that epidermal growth factor (EGF) has the ability to promote in vitro cultured porcine oocyte maturation. However, little is known about the detailed downstream events in EGF-induced meiotic resumption. We designed this study to determine the relationship of EGF, EGFR, phosphatidylinositol 3-kinase (PI3-kinase), MAPK, and germinal vesicle breakdown (GVBD) during oocyte maturation. Our results showed that GVBD in cumulus-enclosed oocytes (CEOs) but not in denuded oocytes (DOs) was induced by EGF in a dose-dependent manner, which indicated that cumulus cells but not oocyte itself were the main target for EGF-induced meiotic resumption. Furthermore, we found that MAPK in cumulus cells rather than in oocyte was activated immediately after EGF administration. To explore whether EGF exerts its functions through MAPK pathway, the activities of EGF receptor (EGFR) and MAPK were inhibited by employing AG1478 and U0126, respectively. Inhibition of MAPK blocked EGF-induced GVBD, whereas inhibition of EGFR prevented MAPK activation. Both AG1478 and U0126 could lead to the failure of EGF-induced GVBD singly. Notably, we found that LY294002, a specific inhibitor of PI3-kinase, effectively inhibited EGF-induced MAPK activation as well as subsequent oocyte meiotic resumption and this inhibition could not be reversed by adding additional EGF. Thus, PI3-kinase-induced MAPK activation in cumulus cells mediated EGF-induced meiotic resumption in porcine CEOs. Together, this study provides evidences demonstrating a linear relationship of EGF/EGFR, PI3-kinase, MAPK and GVBD and presents a relatively definitive mechanism of EGF-induced meiotic resumption of porcine oocyte. 相似文献