State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China; Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen University, Xiamen 361102, China.
National Engineering Research Center of Marine Shellfish, Weihai 264316, China.
Comp Biochem Physiol Part D Genomics Proteomics. 2019 Jun;30:102-112. doi: 10.1016/j.cbd.2019.02.001. Epub 2019 Feb 6.
Hypoxia was thought to inhibit immune responses, causing severe mortality to marine organisms. The Pacific abalone, Haliotis discus hannai, is the most widely cultured abalone species in China, but suffering from "summer mortality" in which hypoxia has been one of the main reasons. The effect of hypoxia exposure on immune responses in H. discus hannai was investigated, including cellular immune response using flow cytometry and transcriptome profiles. The influence of hypoxia treatment on the total hemocyte count (THC) of H. discus hannai was rather limited but the hemocyte survival rate of abalone increased during 48 h exposure. There was an initial rise in the production of phagocytes and reactive oxygen species (ROS) shortly (3 h) after hypoxic stimulation, but finally decreased after 48 h. This indicates that hypoxia inhibited redox activity of abalone. RNA-seq studies of gill tissues also revealed immune response mechanism in abalone after 24 h of hypoxia. Totally 954 differentially expressed genes (DEGs) were detected under different degrees of deoxygenation. Though oxidation-reduction turbulence was a result of both up- and down-regulated DEGs, cell death/apoptosis induction resulted from up-regulated DEGs, whilst DNA metabolic and immunity suppression resulted from down-regulated DEGs. In summary, our data provides evidence that deoxygenation greatly affects abalone immunity, probably making it more vulnerable. The present study also lays the foundation for further research in hypoxia-associated conditions in abalone aquaculture.
缺氧被认为会抑制免疫反应，导致海洋生物死亡率极高。太平洋鲍（Haliotis discus hannai）是中国养殖最广泛的鲍鱼品种，但却遭受“夏季死亡”的困扰，其中缺氧是主要原因之一。本研究探讨了缺氧暴露对 H. discus hannai 免疫反应的影响，包括使用流式细胞术进行细胞免疫反应和转录组谱分析。缺氧处理对 H. discus hannai 总血细胞计数（THC）的影响相当有限，但在 48 小时暴露期间，鲍的血细胞存活率增加。在缺氧刺激后不久（3 小时），吞噬细胞和活性氧（ROS）的产生最初增加，但 48 小时后最终减少。这表明缺氧抑制了鲍的氧化还原活性。对鳃组织进行的 RNA-seq 研究也揭示了缺氧 24 小时后鲍的免疫反应机制。在不同程度的脱氧条件下共检测到 954 个差异表达基因（DEGs）。虽然氧化还原波动是上调和下调 DEGs 的结果，但细胞死亡/凋亡诱导是由上调的 DEGs 引起的，而 DNA 代谢和免疫抑制是由下调的 DEGs 引起的。总之，我们的数据提供了证据表明，缺氧对鲍的免疫力有很大影响，可能使其更容易受到影响。本研究还为鲍养殖中与缺氧相关条件的进一步研究奠定了基础。
