Abstract：
Hydrothermal vents (HVs) and cold seeps (CSs) are typical deep-sea extreme ecosystems with their own geochemical characteristics to supply the unique living conditions for local communities. Once HVs or CSs stop emission, the dramatic environmental change would pose survival risks to deep-sea organisms. Up to now, limited knowledge has been available to understand the biological responses and adaptive strategy to the extreme environments and their transition from active to extinct stage, mainly due to the technical difficulties and lack of representative organisms. In this study, bathymodiolin mussels, the dominant and successful species surviving in diverse deep-sea extreme ecosystems, were collected from active and extinct HVs (Southwest Indian Ocean) or CSs (South China Sea) via two individual cruises. The transcriptomic analysis and determination of multiple biological indexes in stress defense and metabolic systems were conducted in both gills and digestive glands of mussels, together with the metagenomic analysis of symbionts in mussels. The results revealed the ecosystem- and tissue-specific transcriptional regulation in mussels, addressing the autologous adaptations in antioxidant defense, energy utilization and key compounds (i.e. sulfur) metabolism. In detail, the successful antioxidant defense contributed to conquering the oxidative stress induced during the unavoidable metabolism of xenobiotics commonly existing in the extreme ecosystems; changes in metabolic rate functioned to handle toxic matters in different surroundings; upregulated gene expression of sulfide:quinone oxidoreductase indicated an active sulfide detoxification in mussels from HVs and active stage of HVs & CSs. Coordinately, a heterologous adaptation, characterized by the functional compensation between symbionts and mussels in energy utilization, sulfur and carbon metabolism, was also evidenced by the bacterial metagenomic analysis. Taken together, a new insight was proposed that symbiotic bathymodiolin mussels would develop a \"finetuning\" strategy combining the autologous and heterologous regulations to fulfill the efficient and effective adaptations for successful survival.
摘要：
热液喷口（HVs）和冷渗漏（CSs）是典型的深海极端生态系统，具有自身的地球化学特征，为当地社区提供了独特的生活条件。一旦HV或CS停止发射，剧烈的环境变化会给深海生物带来生存风险。到目前为止,有限的知识已经可用来了解极端环境的生物反应和适应策略及其从活跃到灭绝阶段的过渡，主要是由于技术困难和缺乏代表性的生物。在这项研究中,batymodiolin贻贝，在不同的深海极端生态系统中生存的优势和成功物种，是通过两次单独的航行从活跃和灭绝的HVs（西南印度洋）或CSs（南中国海）中收集的。在贻贝的g和消化腺中进行了转录组学分析和应激防御和代谢系统中多个生物学指标的测定，以及贻贝中共生体的宏基因组分析。结果揭示了贻贝的生态系统和组织特异性转录调控，解决抗氧化剂防御中的自体适应，能量利用和关键化合物(即硫)代谢。详细来说,成功的抗氧化防御有助于克服在极端生态系统中普遍存在的不可避免的外源性物质代谢过程中引起的氧化应激；代谢率的变化起到了处理不同环境中有毒物质的作用；硫化物的基因表达上调：醌氧化还原酶表明，从HV和HV和CSs的活跃阶段，贻贝中的硫化物脱毒活性。协调,异源适应，以共生菌和贻贝在能量利用方面的功能补偿为特征，硫和碳代谢，细菌宏基因组分析也证明了这一点。一起来看,有人提出了一个新的见解，即共生的batymodiolin贻贝将开发出一种结合自体和异源调节的“精细调节”策略，以实现成功生存的有效和有效的适应。
