微囊藻对大型溞的雌激素效应及其对温度变化的响应研究

Recently, problems caused by eutrophication and estrogenic pollutants are dramatically increasing in most waterbodies of the world and would be intensified by the globle warming, posing great threat to ecosystem. Microcystis have been found to be a potential source of estrogenic effects in waterbodies. However, their disturbance on zooplankton, the mechanism of these effects and the difference among species, are still not clear. Temperature rising may enhance the negative effects of estrogen, thus the response of Microcystis estrogenic effects to temperature change needs to be clarified. In this study, four strains of Microcystis (both microcystin-producing and non-microcystin-producing strains of Microcystis aeruginosa and Microcystis wesenbergii) will be cultured respectively with Daphnia magna to test the estrogenic effects of Microcystis on zooplankton represented by reproductive, physiological and biochemistry characteristics and gene expression pattern related to estrogenic effects. With a systematic organization from molecular, physiological and ecological evidences, this study will clarify the estrogenic effects and the related mechanisms of blooming Microcystis on zooplankton, reveal the impact of temperature on these effects, the difference among species and the correlation between Microcystis estrogenic effects and the production of microcystins. This study will facilitate to reveal the potential risk and ecological consequence of the interactions between globle warming and Microcystis blooming on aquatic animals.

近年来全球水体富营养化及环境雌激素污染日趋严重，且全球升温将进一步加剧其生态危害。现已发现水华中的微囊藻也可能引发雌激素效应，但其对浮游动物繁殖的干扰程度、作用机制及种间差异等尚不清楚。温度变化会加剧雌激素效应的危害，因此微囊藻的雌激素效应对温度变化的响应也亟待明确。本项目拟以两个微囊藻优势种（铜绿微囊藻和惠氏微囊藻）的产毒株和无毒株为供体藻、大型溞为受试动物，采用藻-溞共培法研究微囊藻对大型溞繁殖特征、雌激素效应相关生理生化指标及基因表达的影响，从分子、生理及生态学层次系统研究微囊藻水华对浮游动物的雌激素效应及其机制，揭示温度变化对该效应的影响、微囊藻雌激素效应的种间差异及与微囊藻毒素的关联性。本研究将有助于揭示全球变暖及微囊藻水华双重胁迫对水生动物的潜在风险及其生态后果。

近年来全球水体富营养化及由此引起的蓝藻水华日趋严重，且全球升温将进一步加剧其生态危害。现已发现水华中的微囊藻也可能引发雌激素效应，本研究验证了微囊藻属代表性优势种铜绿微囊藻和惠氏微囊藻对浮游动物大型溞的繁殖干扰效应，明确了微囊藻胞外分泌物对大型溞产生的雌激素效应和脂质代谢干扰机制；也发现微囊藻对大型溞的雌激素效应在同属种间差异不大；微囊藻无毒株引起的脂质代谢或激素合成干扰是其促进大型溞怀卵的潜在原因，因此微囊藻产毒与否并非其干扰大型溞生殖的必要条件。此外，本研究也观察到温度变化会显著影响微囊藻代谢物的组分结构，其中脂质化合物数量的响应程度最高，且温度升高比降低可能引起大型溞更多参与重要生理过程基因的差异表达（上调或下调）。本研究结果可用于预测全球气候变暖有加剧微囊藻水华干扰浮游动物繁殖的风险，也可能因此进一步改变水生食物链中各营养级的群落结构。因此，在蓝藻水华生态风险防控及湖泊修复应用上提示：有必要将微囊藻无毒株也纳入蓝藻水华生态危害评估，监测最具优势的铜绿微囊藻种群动态的同时也要密切关注惠氏微囊藻。