麻痹性贝毒在虾夷扇贝体内累积、转化和排出过程研究

Accumulation,transformation and depuration of parlytic shellfish toxins by the scallop Patinopecten yessoensis

以我国麻痹性贝毒高发区的虾夷扇贝为研究对象,研究了麻痹性贝毒在扇贝各组织内的累积、转化和排出过程。实验分为洁净海区吊养排毒和室内投喂有毒藻累毒两部分。排毒实验表明,内脏团和鳃排毒率最快,为3.27%/d,外套膜为2.71%/d,证明虾夷扇贝属慢性排毒者。累毒过程中扇贝无不良反应,累毒实验第2 d(A2)扇贝总毒性即达到19.41μgSTXeq/g(干质量),说明虾夷扇贝对麻痹性毒素敏感性低、累积快、累积量大,不同组织对毒素的累积速率差异不大,在4.80%～4.98%/d之间。内脏团及外套膜始终是毒素最主要的分布组织,占总毒素95%以上,闭壳肌最少。扇贝各组织中毒素组分的复杂性与其毒性正相关,且毒素间有转化现象,内脏团和外套膜是最主要的转化组织。主要转化类型有:GTX1,4被还原成GTX2,3;GTX2,3转化为STX;STX转化为dcSTX以及α、β异构体的相互转化。

This study investigated the accumulation,transformation and depuration of paralytic shellfish toxin（PST） in the scallop Patinopecten yessoensi collected from the PST-contaminated area.Two experiments were conducted：in situ depuration of PST in non-PST contaminated sea area and accumulation of PST in laboratory.In the depuration experiment,the visceral mass and gill presented the faster detoxification rate than the mantle,and the average toxin depuration rate reached 3.27% and 2.71% per day,respectively,indicating P.yessoensis was belong to the slow detoxification bivalve.In the accumulation experiment,the total toxicity of the scallop reached 19.41 μg STXeq/g（dry weight）at day two（A2） and no adverse effects were observed during the accumulation experiment,suggesting P.yessoensis has low sensitivity,high tolerance ability to PST with a fast accumulation rate.There was no obvious discrepancy（4.80%~4.98%/day） in accumulation rate between different tissues of P.yessoensis.Toxin content presented the positively correlation ship with the toxin profiles,the visceral mass and mantle contained the higher toxin content and more toxin profiles,while the adductor muscle contained the least.Toxin biotransformation in P.yessoensis was tissues-specific.Transformation in visceral mass and mantle was more significant and the main toxin biotransformation forms occurred as the followings：N-OH toxin GTX1,4 was converted into N-H toxins GTX2,3,GTX2,3 was converted into dcSTX,STX was converted into dcSTX,as well as the reciprocal transformation between isomeric compounds.