UV-B辐射引发海胆躲避行为的主效神经递质和神经肽研究

Behavioral adaptation of marine organisms to UV-B radiation is an important ecological phenomenon. Neural mechanisms, in which neurotransmitters and neuropeptides play important roles, are a key approach to investigating this phenomenon. The present study proposes the sea urchin Strongylocentrotus intermedius as a model to investigate the neurotransmitter and neuropeptide controls of negative phototaxis by sea urchins in response to UV-B radiation. Precursor, receptor and key synthetic enzyme genes of neurotransmitters and neuropeptides will be screened in tube feet between S. intermedius with and without negative phototaxis to UV-B radiation by the method of comparative transcriptomics. Behaviorally related neurotransmitters and neuropeptides will be then screened according to the specific coupling relationship between neurotransmitters and neuropeptides and their precursors, receptors and key synthetic enzymes. Candidate neurotransmitters and neuropeptides will be further screened by testing the content of neurotransmitters and neuropeptides between S. intermedius with and without negative phototaxis to UV-B radiation. Neurotransmitters and neuropeptides with main effects will be finally ascertained by the behavioral observations after the injection of the candidate neurotransmitters and neuropeptidse as well as their depressors. Finally, the single and synergistic effects of the ascertained neurotransmitters and neuropeptides on their behavioral regulations will be carefully investigated. The purpose of the study is to identify the neurotransmitters and neuropeptides with main effects on negative phototaxis to UV-B radiation as well as their single and synergistic behavioral regulations in sea urchins. It will provide new information into the studies of behavioral adaptation of marine organisms to the global changes.

海洋生物对UV-B辐射的行为适应是极具研究价值的生态现象。以主效神经递质和神经肽为突破口的神经机理研究是深入解析这一现象的关键。本项目以潮间带和浅海典型底栖生物中间球海胆为研究对象，利用比较转录组学方法筛选出UV-B辐射下已获得躲避行为的海胆管足中显著差异表达的神经递质和神经肽前体、受体和合成通路上的关键酶基因；进而利用神经递质和神经肽与其前体、受体和关键酶之间的特异性关联筛选出相关神经递质和神经肽；然后重复行为生态学实验，用测定神经递质和神经肽含量的方法做进一步的筛选，获得候选神经递质和神经肽；进而向海胆体内注射候选神经递质和神经肽或其抑制剂以增强或抑制神经传导，然后通过行为学观察最终确定主效神经递质和神经肽；最后深入研究它们单独和协同的行为调控功能。预期结果将揭示UV-B辐射引发海胆躲避行为的主效神经递质和神经肽，明确它们的行为调控功能，为全球变化下海洋生物的行为适应研究提供新的信息。

海洋生物对UV-B辐射的行为反应及其神经生物学机理是极具研究价值的科学问题。本项目以潮间带和浅海典型底栖生物中间球海胆为实验材料，对上述科学问题开展了系统而细致的研究。研究内容和结果总结如下：1）明确了不同强度UV-B辐射对海胆行为的影响；2）对不同行为环境条件下的海胆进行比较转录组学分析，筛选出UV-B辐射下获得躲避行为的海胆管足中显著差异表达基因330个，与NA组相比，SB组存在79个表达上调基因和118个表达下调基因，CB组存在26个表达上调基因和67个表达下调基因。与CB组相比，SB组具有34个表达上调基因和52个表达下调基因，和UV-B辐射响应关系密切；3）基于比较转录组学结果，我们分析发现，5-ht、多巴胺和鱆胺等神经递质和神经肽以及TRPA1和Opsin等“神经哨兵”可能在UV-B辐射引发海胆躲避行为中发挥重要作用，值得进一步深入研究；4）通过在不同行为环境对海胆注射TRPA1的激活剂和抑制剂，并结合TRPA1基因表达分析结果，我们首次报道了TRPA1在海洋无脊椎动物避光行为中的重要调控作用；5）利用类似的研究方法，我们确定了5-ht、多巴胺、鱆胺等神经递质和神经肽在多大程度上对UV-B辐射引发海胆躲避行为进行调控及其协同效应；6）另外，我们对海胆的躲避行为进行了其他方面的拓展研究，丰富了项目内容和结果。本研究成功地完成了项目计划的主体部分；初步阐明了以TRPA1和Opsin为代表的“神经哨兵”和5-ht、多巴胺和鱆胺等为代表的神经递质/神经肽在UV-B辐射引发海胆躲避行为中的作用；发表SCI收录论文8篇（第1标注）；培养优秀硕士研究生2名；为进一步的深入研究奠定了重要的基础。与此同时，我们也更加清醒地认识到了动物行为神经机理的困难和复杂性。