太阳紫外线B波段（UVB）对长牡蛎早期发育及黑色素生成的影响研究

Solar ultraviolet radiation severely impacts a variety of physiological processes of marine life. Depositing melanin is the most common way that animals cope with UVB radiation. From the juvenile stage of Crassostrea gigas, the melanin gradually deposits on its mantle tissue and outer shell. The present study intends to investigate the effects of UVB on the early developmental stage of C. gigas by relying on the long-term low-dose UVB exposure experiment, the analysis of physiological indexes and other technological means such as targeted metabonomics and full-length transcriptome. How the early development and melanogenesis of C. gigas respond to UVB was explained from multiple perspectives including tissue damage, physiological function and changes of gene expression. The research focus is on analyzing the molecular network that regulates the production of melanin in C. gigas and determining key regulatory molecules. The functions of key molecules will be verified by qRT-PCR, Western blot, RNAi and PiggyBac transposon-mediated transgenesis. The findings not only provide a guideline for coping with UVB-driven environmental stress in aquaculture, but also provide effective theoretical basis regarding melanin production to support the breeding of C. gigas with black shell.

太阳紫外辐射可严重影响海洋生物的多种生理过程。而生物体应对UVB辐射的最常见方式便是沉积黑色素。长牡蛎自固着变态后，便会在外套膜组织及外壳上沉积黑色素。本项目通过开展对长牡蛎稚贝的长期低剂量UVB辐射暴露实验，利用生理指标分析、靶向代谢组及全长转录组等技术手段，深入研究长牡蛎早期发育阶段受UVB辐射的影响情况。从组织损伤、生理功能及基因表达变化等多个角度，阐释长牡蛎早期发育及黑色素生成对UVB辐射响应的基本特征。重点分析调控长牡蛎黑色素生成的分子网络，挖掘关键调控分子，通过qRT-PCR、Western blot、RNAi或PB转座子转基因技术等多种实验方法，验证关键调控分子的功能。本研究结果不仅可为水产养殖生产实践提供应对UVB环境胁迫的指导策略，还可为长牡蛎黑壳性状选育提供黑色素生成相关的理论依据。

太阳光照是水生生态系统的一种重要环境因子，具有感光能力的长牡蛎，不论野生还是养殖，其整个生活史均有可能受光的影响。本研究通过表型、行为、生理、分子及多组学结合的手段，综合分析了太阳紫外线B波段（UVB）对长牡蛎的影响情况。本研究首先发现在有UVB的太阳光照条件下，长牡蛎开闭壳行为出现了先调整，再适应的变化规律。同时，UVB辐射也可影响长牡蛎贝壳的正常钙化过程。其次，多组学分析长牡蛎血浆物质发现UVB辐射对长牡蛎产生的3大影响：破坏细胞膜，促进核苷酸代谢，抑制能量代谢。最后，通过多种手段结合，在外套膜组织中阐释了牡蛎对UVB辐射的响应机制，推测外套膜细胞表面的受体感受到太阳UVB的影响后，可通过释放到细胞内的3种第二信使cAMP，cGMP及Ca2+，在细胞内部传递光的影响，激活细胞核内转录因子CgRunx1，在转录水平上调控相关靶基因的特异表达，进而调节长牡蛎的黑色素生成、钙化、自噬等生理过程。本研究明确了UVB辐射暴露对长牡蛎的影响情况，丰富了贝类的色素沉积机制和环境变化生理响应研究。