温度影响对虾白斑综合症病毒增殖机制的研究

A study on the mechanism of temperature impact on the proliferation of white spot syndrome virus (WSSV)

已有文献报道温度是影响虾类感染对虾白斑综合症病毒(WSSV)的重要因素但并不清楚其机制.在本实验中我们通过定量检测病毒拷贝数后发现环境温度与病毒增殖速度有相关性.当温度在21～30℃之间时病毒增殖速度最快,病虾于感染后6～8 d全部死亡而高温(33℃)及较低温度(15～18℃)对病毒的增殖均具有一定的抑制作用,虾存活时间超过了14 d;当温度降至12℃或8℃时病毒增殖受到明显抑制,虾存活时间长达40 d.通过激光共聚焦显微镜观察进一步发现病毒进入宿主细胞的能力与温度密切相关,高温(33℃)和低温(12℃)下病毒进入细胞的数量明显比27℃时少;而通过对病毒ie1和vp28基因的转录分析发现与27℃相比,高温(33℃)和低温(12℃)明显改变了病毒基因的转录.本实验结果表明温度影响WSSV基因组的复制、转录及病毒入侵细胞的能力从而导致了病虾死亡时间上的差异.

It had been reported that temperature was one of the most important elements affecting the shrimp infected by WSSV. However the mechanism of the influence is not clear. In this study, we found that there was a relation between the proliferation speed of WSSV and the ambient temperature by measuring the viral genome copies. The speed of viral proliferation was highest from 21℃ to 30℃ and all the crayfish died within 8 days. The viral replica- tion was delayed at 33℃ or between 15℃ and 18℃ and the survival time of crayfish lasted for more than 14 days. When the surrounding temperature drops below 12℃, the replication of WSSV was significantly inhibited, leading to 100% survival up to 40 days. Results from laser scanning confocal microscope（LSCM） showed that the ability of the fluorescence labeled viruses entry into lymphocytes at 27℃ was significantly higher than other temperatures. The transcript data also showed that the temperature influenced the expression of viral immediate-early gene iel and late gene vp28. Our results suggested that temperature plays a critical role in viral entry, transcription and genome replication.