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.

在以前的工作中，研究人员已经证明了对有毒甲藻Alexandrum sp.的遗传适应，在一种桡足类中，哈氏纺锤水蚤。最近，他们在A.哈德森尼卡。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适应有毒藻类的问题。该项目将通过以下方式对草食动物中的毒素抗性表型的发现采取后续行动：1）开发区分表型的简单测定法; 2）证明不同的表型是遗传的; 3）确定抗性表型是否也与耐饥饿性有关; 4）确定毒素抗性表型、肠道停留时间和摄食之间的联系;并制作与浮游动物，有毒藻类和进化有关的教育材料，这些材料符合国家科学教育标准和海洋扫盲基本原则和基本概念。实现这些目标可能会导致在海洋生态学和进化的新的研究路径。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，未来的研究必须考虑它们。例如，目前在许多研究中，选择性放牧的不可预测的出现没有统一的解释。解释自然和实验室种群中抗性表型的频率可能会解开这个谜团。此外，这项研究可能很好地解释了机械科目的扭曲桡足类性别比例在现场观察和草率喂养在实验室中观察到的变化。最后，如果放牧在水华的形成或终止中起重要作用，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水华的影响。然而，迄今为止的大多数工作都是由自下而上的思维驱动的。有毒浮游植物的损失条件，如放牧，受到的关注要少得多。草食动物对有毒藻类的局部适应（抗性）是一种潜在的反馈机制，从而导致水华控制。另一方面，食草动物的抵抗力可能会导致毒素转移到人类食用的顶级捕食者，从而导致与浮游植物水华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一般性及其性质，以便设计和实施明智的管理策略，以减轻有毒水华。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，还将通过网站、光盘和讲习班广泛提供这些材料。这部分工作将在全国科学家和中等教育工作者会议上介绍。此外，拟议的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。