The Adaptive Importance of Toxin-Resistant Phenotypes in Calanoid Copepods

桡足类毒素抗性表型的适应性重要性

• 批准号: 0648126
• 负责人: Hans Dam
• 金额: $ 37万
• 依托单位: University of Connecticut
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-03-01 至 2012-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0648126&HistoricalAwards=false
• 关键词: Adaptive; Importance; Toxin; Resistant; Phenotypes

In previous work the Investigators have demonstrated genetic adaptation to the toxic dinoflagellate, Alexandrium sp., in one species of copepod, Acartia hudsonica. Recently, they discovered several classes of toxin-resistant phenotypes within A. hudsonica. This finding has profound implications for understanding predator-prey interactions in the oceans, well beyond the question of grazer adaptation to toxic algae. This project will follow-up on the discovery of toxin-resistant phenotypes in grazers by: 1) developing simple assays to distinguish phenotypes; 2) demonstrating that distinguished phenotypes are genetic; 3) determining if the resistant phenotypes are also related to resistance to starvation; 4) identifying linkages between toxin-resistant phenotypes, gut residence time and ingestion; and producing educational materials related to zooplankton, toxic algae, and evolution that align with the National Science Education Standards and Ocean Literacy Essential Principles and Fundamental Concepts. Achieving these objectives will likely lead to new research paths in ocean ecology and evolution. If resistant phenotypes are common among grazers, then prior results will need to be reconsidered and future studies must account for them. For example, currently there is no unifying explanation for the unpredictable appearance of selective grazing in many studies. Accounting for the frequency of resistant phenotypes in natural and laboratory populations could potentially solve this mystery. In addition, this study may very well explain mechanistically subjects as varied as distorted copepod sex ratios observed in the field and sloppy feeding observed in the laboratory. Finally, if grazing is important in the formation or termination of blooms, then resistant phenotypes could very well be central to the phenomenon.There is an immediate and urgent societal need to mitigate the effects of toxic phytoplankton blooms. Most of the work to date, however, is driven by bottom up thinking. The loss terms of toxic phytoplankton such as grazing have received much less attention. Local adaptation (resistance) of grazers to toxic algae is a feedback mechanism potentially leading to bloom control. On the other hand, grazer resistance may result in enhanced toxin transfer to top predators consumed by humans, and consequently lead to exacerbation of public health problems related to phytoplankton blooms. Therefore, it is imperative that we gain a full understanding of the generality of grazer resistance and of its nature in order to design and implement well-informed management strategies for toxic bloom mitigation. In addition, there is also an immediate and urgent need to improve the public's awareness of publicly funded science, evolution, and the world's oceans. To help fill this need, the results of this study will be organized by professional educators into prepared curricular materials that meet national standards. Further, the material will be made widely available via a website, CD's and workshops. This portion of the work will be presented at national meetings of scientists and secondary educators. In addition, the proposed work will also train a graduate student in zooplankton ecology, evolution and toxic algae research.

在之前的工作中，研究人员已经证明了一种桡足动物——哈德逊阿卡迪亚（carartia hudsonica）对有毒鞭毛藻亚历山大菌（Alexandrium sp.）的遗传适应性。最近，他们在哈德逊芽孢杆菌中发现了几种抗毒素表型。这一发现对于理解海洋中捕食者-猎物的相互作用具有深远的意义，远远超出了食草动物对有毒藻类的适应问题。该项目将通过以下方式追踪食草动物中毒素抗性表型的发现：1)开发简单的检测方法来区分表型；2)证明不同的表型是遗传的；3)确定抗性表型是否也与饥饿抗性有关；4)确定毒素抗性表型、肠道停留时间和摄食之间的联系；制作与《国家科学教育标准》和《海洋素养基本原则和基本概念》相一致的有关浮游动物、有毒藻类和进化的教材。实现这些目标可能会为海洋生态学和进化带来新的研究途径。如果抗性表型在食草动物中很常见，那么之前的结果将需要重新考虑，未来的研究必须解释它们。例如，目前在许多研究中对不可预测的选择性放牧现象没有统一的解释。对自然种群和实验室种群中耐药表型的频率进行解释可能会潜在地解开这个谜团。此外，这项研究可以很好地解释各种各样的实验对象，如在野外观察到的扭曲的桡足动物性别比例和在实验室观察到的草率喂养。最后，如果放牧对开花的形成或终止很重要，那么抗性表型很可能是这一现象的核心。社会迫切需要减轻有毒浮游植物大量繁殖的影响。然而，迄今为止的大部分工作都是由自下而上的思维驱动的。有毒浮游植物的损失，如放牧，受到的关注要少得多。食草动物对有毒藻类的局部适应（抗性）是一种反馈机制，可能导致水华控制。另一方面，食草动物的抗性可能导致毒素转移到被人类食用的顶级捕食者身上，从而导致与浮游植物大量繁殖有关的公共卫生问题加剧。因此，我们必须充分了解食草动物抗性的普遍性及其性质，以便设计和实施信息灵通的管理策略，以减轻毒华。此外，还迫切需要提高公众对公共资助的科学、进化和世界海洋的认识。为了帮助满足这一需求，这项研究的结果将由专业教育工作者组织成符合国家标准的课程材料。此外，将通过网站、CD和讲习班广泛提供这些材料。这部分工作将在科学家和中等教育工作者的国家会议上提出。此外，这项工作还将培养一名浮游动物生态学、进化和有毒藻类研究方面的研究生。