海月水母螅状体耐受低氧的分子机制

The occurrence of hypoxia zones and the bloom of giant jellyfish in estuaries, bays and coastal waters in the last few years seriously affect the health of the fishery resources and stability of marine coastal ecosystem. Compared with other marine organisms, most jellyfish can frequently appear in oxygen minimum zones and have the hypoxia tolerance. However, there are few studies on the mechanisms of hypoxia tolerance and response in jellyfish. Therefore, this research will employ the method of combining controlled ecological experiment with molecular biological technology to fully uncover the molecular regulation mechanism of hypoxia tolerance about different stages of the life history in Aurelia sp.1 by studying the transcriptome, physiological activity, the expression of related genes and proteins in hypoxia-inducible factor-prolyl hydroxylases oxygen sensing system, related genes of material energy metabolism and the content of metabolites of polyps under hypoxia and saturated dissolved oxygen conditions respectively. This study will provide the scientific basis for clarifying the correlation between marine hypoxia and jellyfish blooms and revealing the key environmental factors which cause the jellyfish blooms.

近年来频繁出现的海洋低氧和大型胶质类水母的暴发严重威胁到近海渔业资源的健康和生态系统的稳定。相对于其它海洋生物，水母能够耐受低氧并且频繁出现在低氧水域，但是对此现象的机制性研究并不多见。本研究采用室内受控实验和分子生物技术相结合的方法，在前期对海月水母体低氧耐受机制研究的基础上，对低氧和饱和氧条件下的海月水母螅状体转录组、生理活性、脯氨酸羟基化酶-低氧诱导因子氧感受体系相关基因及其蛋白表达、能量代谢相关基因的表达情况以及代谢产物的含量进行研究，全面揭示海月水母生活史不同阶段耐受低氧环境的分子调控机制，从而理解海洋低氧与水母暴发的相互关系，为解析控制水母暴发的关键环境因子提供重要科学依据。

近年来，全球海洋中水母的数量、出现频率和影响范围均呈现逐年增加的趋势，许多海域出现水母大规模暴发现象，甚至已经达到泛滥的程度，多次造成沿海核电站停机停堆，引发了社会公众的广泛关注。本研究以我国近海大量出现且实现实验室室内培养的海月水母水螅体为研究对象，构建低氧培养控制体系，利用转录组、代谢组和实时荧光定量PCR等分子生物学技术，比较分析了正常氧、0.5mg/L和0.2mg/L溶解氧条件下海月水母水螅体HIF-PHD氧感受体系相关基因以及糖酵解关键基因和关键代谢产物随时间的变化规律来揭示海月水母耐受环境低氧的分子调控机制，为分析海月水母螅状体的种群竞争优势和解析控制水母暴发的关键环境因子提供依据。.0.5mg/L低氧条件下，海月水母螅状体PHD-HIF氧感受体系相关基因的表达明显受低氧诱导，但并未影响PDK和LDH基因的表达，说明低氧条件未达到开启螅状体有氧向无氧代谢的转换的需求；0.2 mg/L低氧条件下，海月水母螅状体PHD-HIF氧感受体系相关基因的表达明显受低氧诱导，糖酵解途径相关基因表达上调，乳酸相对含量明显增加，说明0.2 mg/L的低氧明显对海水水母螅状体产生胁迫，导致其物质能量代谢方式由有氧代谢向无氧代谢转换。