Ocean College, Zhejiang University, Zhoushan, 316000, China.
Ocean College, Zhejiang University, Zhoushan, 316000, China.
Mar Environ Res. 2024 Jul;199:106610. doi: 10.1016/j.marenvres.2024.106610. Epub 2024 Jun 13.
Deep-sea mussels, one of the dominant species in most deep-sea ecosystems, have long been used as model organisms to investigate the adaptations and symbiotic relationships of deep-sea macrofauna under laboratory conditions due to their ability to survive under atmospheric pressure. However, the impact of additional abiotic conditions beyond pressure, such as temperature and light, on their physiological characteristics remains unknown. In this study, deep-sea mussels (Gigantidas platifrons) from cold seep of the South China Sea, along with nearshore mussels (Mytilus coruscus) from the East China Sea, were reared in unfavorable abiotic conditions for up to 8 days. Integrated biochemical indexes including antioxidant defense, immune ability and energy metabolism were investigated in the gill and digestive gland, while cytotoxicity was determined in hemocytes of both types of mussels. The results revealed mild bio-responses in two types of mussels in the laboratory, represented by the effective antioxidant defense with constant total antioxidant capability level and malondialdehyde content. There were also disparate adaptations in deep-sea and nearshore mussels. In deep-sea mussels, significantly increased immune response and energy reservation were observed in gills, together with the elevated cytotoxicity in hemocytes, implying the more severe biological adaptation was required, mainly due to the symbiotic bacteria loss under laboratory conditions. On the contrary, insignificant biological responses were exhibited in nearshore mussels except for the increased energy consumption, indicating the trade-off strategy to use more energy to deal with potential stress. Overall, this comparative study highlights the basal bio-responses of deep-sea and nearshore mussels out of their native environments, providing evidence that short-term culture of both mussels under easily achievable laboratory conditions would not dramatically alter their biological status. This finding will assist in broadening the application of deep-sea mussels as model organism in future research regardless of the specialized research equipment.
深海贻贝是大多数深海生态系统中的优势物种之一，由于其能够在大气压下生存，因此长期以来一直被用作模型生物，以研究深海大型动物在实验室条件下的适应和共生关系。然而，除了压力之外，温度和光照等额外的非生物条件对其生理特征的影响尚不清楚。在这项研究中，来自南海冷泉的深海贻贝（Gigantidas platifrons）和来自东海的近岸贻贝（Mytilus coruscus）在不利的非生物条件下被饲养了长达 8 天。在鳃和消化腺中研究了包括抗氧化防御、免疫能力和能量代谢在内的综合生化指标，同时还测定了两种贻贝的血细胞的细胞毒性。结果表明，两种贻贝在实验室中表现出温和的生物反应，以恒定的总抗氧化能力水平和丙二醛含量表示有效的抗氧化防御。深海贻贝和近岸贻贝也表现出不同的适应能力。在深海贻贝中，观察到鳃中的免疫反应和能量储备显著增加，同时血细胞中的细胞毒性升高，这表明需要更严重的生物学适应，主要是由于实验室条件下共生细菌的丧失。相比之下，近岸贻贝除了能量消耗增加外，没有表现出明显的生物反应，这表明了一种权衡策略，即用更多的能量来应对潜在的压力。总的来说，这项比较研究强调了深海贻贝和近岸贻贝在原生环境之外的基本生物反应，为两种贻贝在容易实现的实验室条件下进行短期培养不会显著改变其生物学状态提供了证据。这一发现将有助于拓宽深海贻贝作为未来研究模型生物的应用，而无需专门的研究设备。
