普氏原羚对环境硒胁迫的响应机制

Selenium is an essential trace element for animal, severe selenium deficiency will lead to death of the individual, population collapse and the endangered species. However, we did not discover any clinical sign of selenium deficiency in the critically endangered przewalski's gazelle which is living in severe selenium deficiency range of the Qinghai lake watershed, China. Many hypothesis of foraging behavior think that animals can select forage according to their nutritional needs. In the present study, the correlation between selenium content of forage and selected index of animals foraging was-0.39, significance probability level was 0.029. The Przewalski's gazelle do not selected rich Se plants as forage, how do animals cope with selenium deficiency? Therefore, we hypothesized that the physiological adaptation mechanism of animal has formed to cope with circumstances of Se deficiency, gene expression of functional protein in liver and blood has obvious difference between animals of Se deficiency pasture and animals in rich Se steppe. The functional protein formed adaptive evolution and new function or strengthen existing function. Adaptive changes have engendered in hemorheology property. We studied the geographical distribution characteristics of selenium in the Qinghai lake watershed. Isotope labeled relative and absolute quantitative techniques (ITRAQ) were used to isolate and identify the differentially expressed proteins from liver and blood which associated with Se deficiency in Przewalski's gazelle. The specificity of differently expressed proteins will been validate by protein blotting (Western blot), and MS with multiple reaction monitoring technology (MRM). Selected potential indicators for monitoring selenium deficiency will been find by bioinformatics. We will analysis correlation of hemorheological property, biochemical indicator and differential protein expression by bioinformatics. Response mechanism of the przewalski's gazelle to selenium deficiency of natural habitat will be elucidated by hemorheology, bioinformatics, biochemistry and proteomics.

硒是动物必需的矿物质营养，严重硒缺乏必然导致个体死亡，种群崩溃，物种濒临灭绝，但生存于硒缺乏区的普氏原羚却不见缺硒表症。觅食行为生态学认为：动物能根据自身营养需要选择植物。最近研究发现：普氏原羚对植物的选择指数同硒含量的相关系数R=-0.390，显著性概率水平P=0.029，有意回避高硒植物。因此，提出假说：普氏原羚对环境硒胁迫形成了生理适应机制，血浆和肝脏部分功能蛋白表达存在明显差异，发生了适应性进化，加强了已有功能或产生了新的功能，生理生化指标和血液流变学性质发生了适应性变化。在研究青海湖流域硒地理分布特点的基础上，应用同位素标记相对与绝对定量技术筛选肝脏和血浆中的差异蛋白，采用蛋白质印迹法和质谱多反应监测技术验证差异蛋白的特异性，利用生物信息学技术确定硒缺乏潜在的监测指标。分析差异蛋白、血液流变学性质、生理生化指标之间的相互关系。在蛋白质水平阐明普氏原羚对环境硒胁迫的响应机制。

普氏原羚是中国特有珍稀濒危物种，为了给保护工作提供新的思路，我们研究了土壤、牧草、动物组织的矿物质元素的分布特点，应用分子生物学、流变学和组学等技术，探索生理生化、流变学参数、差异蛋白和差异代谢物的变化规律，揭示普氏原羚对自然栖息地环境硒胁迫的响应机制。研究结果表明：硒胁迫显著降低血硒含量，增加了铜、锰和锌的含量，显著降低了谷胱甘肽过氧化物酶的活性，增加了超氧化物岐化酶的活力。但血清总抗氧化力和丙二醛的含量无显著差异。蛋白组学研究共鉴定到130个差异蛋白，其中上调蛋白70个，下调蛋白60个。生物信息学分析发现27个差异蛋白与硒的生物学功能相关。基因本体数据库注释分析显示，差异蛋白主要参与了细胞组成、生物学过程和分子功能调节等。通路注释富集分析表明，差异蛋白主要富集在凝血补体级联反应信号通路、血小板活化和胰液分泌通路等。蛋白互作网络分析结果显示，许多节点蛋白参与细胞生化过程调控或信号传导途径调节。代谢组学研究发现阳离子峰数目6060个，阴离子峰数目7897个。PCA得分图显示血清代谢轮廓差异明显，OPLS-DA得分图显示组间血清代谢产物差异明显。差异显著性分析发现，在阳、阴离子模式分别有40和53种代谢物出现了显著性差异。热图结果显示，阳离子模式下有23种代谢物上调，17种代谢物下调；阴离子模式下，有23种代谢物上调，30种代谢物下调。KEGG代谢途径分析发现，硒胁迫影响96个可能途径，涵盖48种特定代谢产物。主要代谢途径涉及胆汁酸合成、胆汁分泌和蛋白质消化吸收等，影响了机体脂质代谢、能量代谢和免疫系统等。.结论：1、硒胁迫引起血清硒含量的降低，铜、锌和锰含量升高，引起抗氧化酶活性的改变，但总抗氧化力无显著差异。2、蛋白组学研究表明激活了凝血补体级联反应信号通路，补偿性地增加了机体免疫力。3、代谢组学研究发现假尿苷是硒胁迫的生物标志物，变化倍数FC=1.174172，远远低于致病浓度。