摘要
波罗的海鲑鱼患有母体传播性卵黄囊期仔鱼死亡综合症——M74。M74综合症的发生具有年际波动。20世纪90年代死亡率达50%~80%,而2003~2005年则低于10%。患M74综合症的仔鱼在死亡前具有一些典型症状。M74综合症鱼卵具有典型的低硫胺素水平和类胡萝卜素含量,患病仔鱼具有氧化胁迫症状。虽然已知M74综合症与硫胺素缺乏有关,且添加硫胺素可使仔鱼的症状得以缓解,但M74综合症的根本病因尚不清楚。本文从分子水平对M74综合症进行了研究,采用cDNA微阵列基因表达谱分析,对健康卵黄囊和M74综合症卵黄囊中的转录水平变化进行了定量分析。根据本文及前人的研究结果,波罗的海鲑鱼卵黄囊仔鱼M74综合症的病因是氧化胁迫导致的几种发育分子通路紊乱。因为M74综合症是母体起源的,在鲑鱼索饵和洄游过程中波罗的海中一些因子,如食物化学组成,可能在M74综合症形成过程中具有决定性作用。文章还讨论了氧化胁迫在成年鲑鱼发育过程中可能出现的机制。
Baltic salmon suffer from maternally transmitted yolk-sac fry mortality syndrome—M74.The incidence of M74 varies considerably on a year to year basis.In the 1990s the mortalities were 50-80% but in 2003-2005, below 10%.Before death,M74-affected fry have several typical symptoms. M74-eggs are characterized by low thiamine and carotenoid content,and affected fry show signs of oxidative stress.Although M74 is associated with thiamine deficiency and the symptoms of the fry can be alleviated with thiamine,the underlying causes of the syndrome have remained a mystery.We have studied the symptoms of M74 at the molecular level by investigating the global gene expression patterns using cDNA microarray and have quantified the changes in ranscriptional regulation in M74-affected and healthy yolk-sac fry.Our nd previous results suggest that M74 in Baltic salmon yolk-sac fry esults from oxidative stresses disturbing several different developmental olecular pathways.Because the M74 syndrome is of aternal origin,factors in the Baltic Sea during salmon feeding and igration, i.e.,the chemical composition of food,may be decisive in he development of M74.The possible mechanisms by which oxidative tresses may develop in adult salmon are discussed in the review.