DISSERTATION RESEARCH: Behavioral and Reproductive Implications of Nanomaterial and Synthetic Estrogen Co-Exposures in Fish

人造纳米材料（NM）的潜在应用数量在世界各地呈指数级增长，但却没有对无意或有意释放到环境中的可能后果进行相应的研究。 鱼类和其他水生生物生活在可能处置纳米物质的水体中。 越来越多的证据表明，一些纳米物质，根据其组成，大小或表面功能化，可以影响鱼类健康。 本研究的目的是评估纳米物质是否会干扰鱼类的繁殖行为。 这个项目很重要，因为行为的改变会对遗传和种群产生破坏性的影响。这里提出的研究将填补一个很大的空白，在理解工程纳米材料的生态毒理学影响，可能会被释放到环境中。最后，像这样的研究将通过明确定义使NM生物的特征来影响NM的发展，本论文研究的总体目标是，通过灌胃经口引入鱼类的NM可以通过肠道渗透到血液中，然后分配到器官中，在那里它们可以进一步影响细胞机制包括类固醇生成。 口服剂量的量子点（QD）穿过肠道上皮并在包括性腺在内的各种组织中积累，这表明它们可能对组织功能产生深远的影响。 这个项目将专门解决一个新的假设，即纳米材料能够干扰黑头呆鱼的生殖行为。 已知内源或外源类固醇激素控制鱼类的生殖行为。 待测试的具体假设是（A）官能化QD将内化到睾丸中并干扰类固醇生成并改变雄性生殖行为，以及（B）单壁碳纳米管将结合并隔离外源添加的乙炔基雌二醇并抑制雄性行为的女性化。 这些假设将在体内研究中进行测试，以确定纳米材料和环境雌激素（EE）对黑头呆鱼，黑头呆鱼的基因表达和竞争性生殖行为之间的相互作用。 预期的结果是：（1）SWCNT将降低EE的生物利用度，并最终改变筑巢和防御行为，（2）QD将导致FHM的生殖行为缺陷，以及（3）QD产生的影响将因EE共同暴露而加剧。

The number of potential applications for manufactured nanomaterials (NMs) is growing exponentially around the world, without concomitant research into the possible consequences of inadvertent or purposeful releases into the environment. Fish and other aquatic organisms reside in bodies of water where NMs are likely to be disposed. A growing body of evidence suggests that some NMs, depending on their composition, size or surface functionalization, can affect fish health. The goal of this study is to evaluate if NMs can interfere with fish reproductive behavior. This project is important because alterations in behavior can have devastating genetic and population effects. The research proposed here will fill a large gap in the understanding of the ecotoxicological implications of engineered NMs that may be released into the environment. Ultimately, studies like this one will influence NM development by clearly defining the characteristics that make NMs bio-active and that should be considered in manufacturing and future environmental regulatory policies.The overarching goal of this thesis research is that NMs introduced into fish orally through gavage can penetrate through the intestine into the blood stream and then partition into organs where they can further impact with cellular mechanisms including steriodogenesis. Orally dosed quantum dots (QDs) cross the gut epithelium and accumulate in various tissues including the gonads, suggesting they may have profound effects on tissue function. This project will specifically address a new hypothesis that NMs are able to interfere with reproductive behaviors of fathead minnows. It is known that endogenous or exogenous steroid hormones control reproductive behavior of fish. The specific hypotheses to be tested are (A) that functionalized QDs will be internalized into testis and interfere with steroidogenesis and alter male reproductive behavior, and (B) that single walled carbon nanotubes will bind and sequester exogenously added ethinylestradiol and inhibit feminization of male behavior. These hypotheses will be tested using in vivo studies to determine the interactions between NMs and environmental estrogen (EE) on gene expression and competitive reproductive behavior in fathead minnows, Pimephales promelas. The expected outcomes are that (1) SWCNTs will reduce EE bioavailability and ultimately alter nest holding and defending behavior, (2) QDs will cause reproductive behavioral deficits in FHMs, and (3) that the effects produced by QDs will be exacerbated by EE co-exposure.