Das B K, Collet B, Snow M, Ellis A E
Central Institute of Freshwater Aquaculture, Kausalyaganga, Bhubaneswar, India.
Fish Shellfish Immunol. 2007 Sep;23(3):514-20. doi: 10.1016/j.fsi.2006.10.010. Epub 2006 Nov 3.
The expression in kidney tissue of interferon type I (IFNalpha) and type II (IFNgamma) genes and two of their inducible genes, Mx and gammaIP were monitored, using qRT-PCR, in a population of Atlantic salmon prior to and over the period of smolting and sea water transfer. The smolting process was induced by photoperiod manipulation in October and smolts were transferred to sea water in December. Prior to extending the light period in October, the fish showed extremely low level expression of the genes assayed. However, immediately on extending the light and up until 1 week after transfer to sea water, 26 of the 90 fish sampled showed up-regulated expression for IFNalpha, Mx and gammaIP. The highest levels were shown by two fish on the 2 days prior to sea water transfer. Eleven fish displayed elevated expression of IFNgamma but there was no apparent association with smolting or sea water transfer or expression of the other genes. At the end of the sampling period, 30 fish were tested by standard virological methods and found to be virus free. The results indicate that during the smolting process, Atlantic salmon consititutively express IFNalpha and Mx mRNA. Those individuals which express Mx close to the time of transfer to sea water would be expected to have high levels of the anti-viral Mx protein in tissues for the longest time after sea water transfer. This could provide an innate defence against viral pathogens which post-smolts may encounter for the first time on entering the marine environment. Those individuals which express Mx early in the smolting process may be more at risk of developing IPN or other viral diseases as post-smolts.
在大西洋鲑鱼的一个群体中，于洄游前期以及洄游和海水转移期间，使用定量逆转录聚合酶链反应（qRT-PCR）监测了I型干扰素（IFNα）和II型干扰素（IFNγ）基因及其两个诱导基因Mx和γIP在肾脏组织中的表达情况。洄游过程通过10月的光周期调控诱导，洄游幼鱼于12月转移至海水中。在10月延长光照期之前，所检测基因在鱼体内的表达水平极低。然而，在延长光照后即刻以及直至转移至海水后1周，所采集的90条鱼中有26条的IFNα、Mx和γIP表达上调。在转移至海水前2天，两条鱼的这些基因表达水平最高。11条鱼的IFNγ表达升高，但与洄游、海水转移或其他基因的表达无明显关联。在采样期结束时，30条鱼通过标准病毒学方法检测，结果显示无病毒感染。结果表明，在洄游过程中，大西洋鲑鱼组成性表达IFNα和Mx mRNA。那些在转移至海水时接近表达Mx的个体，预计在海水转移后的最长时间内，其组织中会有高水平的抗病毒Mx蛋白。这可为洄游后幼鱼首次进入海洋环境时可能遇到的病毒病原体提供先天性防御。那些在洄游过程早期表达Mx的个体，作为洄游后幼鱼，可能更易患传染性胰腺坏死病（IPN）或其他病毒性疾病。
