Analysis of differentially expressed genes in the sea cucumber Apostichopus japonicus under heat stress. Analysis of differentially expressed genes in the sea cucumber Apostichopus japonicus under heat stress

The high-throughput RNA-seq was applied under both 26°C and 30°C heat stress in Apostichopus japonicus, which revealed characterization of gene expression at sub-lethal and lethal limit temperature. The results will help to better understand the characteristics of heat shock response in A. japonicus. Overall design: The sea cucumbers in control group were still kept at 18°C without any change, and the intestine tissue was sampled from the control group. For the heat stress experiment, sea cucumbers went through a temperature-rise process from 18°C to 26°C or to 30°C respectively, with a rate of 2°C per hour by using a heating rod. Then the water maintained at the treatment temperature, and the initial time was set with the moment when the temperature reached 26°C or 30°C. After 6 h and 48 h from initial time, the sea cucumbers 26°C treatment were sampled with intestine tissue, which was regarded as the group 26°C_6h and 26°C_48h respectively. After 6 h from initial time, the sea cucumbers 30°C treatment were sampled with intestine tissue, which was regarded as the group 30°C_6h. All the samples were quickly frozen in liquid nitrogen, and then stored at -80°C for further usage.

本研究对仿刺参（Apostichopus japonicus）分别在26℃和30℃热胁迫（heat stress）条件下开展高通量RNA测序（high-throughput RNA-seq），解析了其在亚致死和致死极限温度下的基因表达特征。研究结果有助于更深入理解仿刺参的热休克响应（heat shock response）特性。实验整体设计如下：对照组仿刺参始终维持在18℃且无任何环境变动，采集其肠道组织作为对照样本。热胁迫实验组采用加热棒（heating rod）以每小时2℃的升温速率，将养殖水温从18℃分别升至26℃或30℃；待水温达到设定的目标温度（26℃或30℃）时记为初始处理时刻，此后维持恒温处理。对于26℃处理组，分别在初始时刻后的6小时和48小时采集肠道组织，对应设为26℃_6h组与26℃_48h组；对于30℃处理组，仅在初始时刻后的6小时采集肠道组织，设为30℃_6h组。所有采集得到的组织样本均迅速置于液氮（liquid nitrogen）中速冻，随后保存于-80℃冰箱以备后续实验使用。