舍曲林对蚤状溞诱导型反捕食防御代内与代际可塑性的干扰效应

表型可塑性是指生物(尤其是单一基因型)在适应异质环境时表达出不同表型的能力，并且有遗传基础。环境变化调控表型可塑性既可以发生在个体发育进程中(称为代内表型可塑性),也能够以可遗传表型响应的形式持续多个生物世代(称为代际表型可塑性)。浮游动物枝角类常常受到来自鱼类的捕食风险影响而表现出诱导型防御的表型可塑性。诱导型防御的表达在很大程度上受到代谢稳态控制，因此枝角类的诱导型防御的表达容易受到内稳态代谢干扰物(例如抗抑郁药舍曲林)的影响。考虑到舍曲林在水中生物活性高且难以被降解；同时，枝角类世代周期较短，因此需要评估连续多代舍曲林暴露对枝角类反捕食防御代内以及代际可塑性的影响。结果发现：在代内可塑性方面，连续两代的舍曲林暴露放大了鱼类信息素诱导的蚤状溞体长减小趋势以及相对尾刺长度增长趋势，但是对鱼类信息素作用下的种群适合度参数无明显干扰。在代际可塑性方面，随着连续两代舍曲林的浓度上升，亲代经历鱼类信息素产下的子代继续响应鱼类信息素时，体长减小、相对尾刺长度增大，说明形态防御得到加强；同时种群净繁殖量以及种群内禀增长率下降的趋势被放大，由此可能抑制鱼类捕食风险下蚤状溞的种群丰度。上述结果表明，...

Interference effect of sertraline on phenotypic plasticity within- and trans-generations of induced anti-predator defense in Daphnia pulex

Phenotypic plasticity is the ability of an organism to show various phenotypes which is based on genetic basis and mostly influenced by environmental heterogeneity. Research has shown that a change in environmental conditions could alter the expression of traits during development (i.e., within-generational plasticity) as well as induce heritable phenotypic responses that persist for multiple generations (i.e., trans-generational plasticity). Cladoceran zooplankton often exhibit plasticity of inducible defenses in response to fish predation risks. Given that inducible defense may depend to a great extent on basic metabolic fitness of cladocerans, disrupting chemicals in homeostasis (e.g. antidepressant sertraline) may therefore modify the expression of inducible defense. Since sertraline has highly biological activity and longstanding persistent in water, together with short generation time of cladocerans, there is an urgent need to understand the influence by multigenerational exposure of sertraline on the within- and trans-generational inducible defense of cladocerans. The results showed that two-generational exposure of sertraline modified the predator-induced phenotypic plasticity within-generation, expressed as morphological enhancement of body-size reduction, relative-spine-length elongation found in predation-induced Daphnia pulex as opposed to predation-free animals. No predation-induced variation in D. pulex population fitness seemed to be associated with the sertraline exposure. Furthermore, we found that two-generational exposure of sertraline mediated the trans-generational inducible defense, expressed as enhanced morphological response but simultaneously a population fitness cost. Collectively, our results denote that although long-term exposure to sertraline has marginal mortality to zooplankton, it still negatively affects within- and trans-generational plasticity in the inducible defense of cladocerans as well as their population abundance and may consequently dull antipredation response involved in the structure and function of ''prey-predator'' interaction.