The planocerid flatworm is a main supplier of toxin to tetrodotoxin-bearing fish juveniles
The planocerid flatworm is a main supplier of toxin to tetrodotoxin-bearing fish juveniles
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DOI：
10.1016/j.chemosphere.2020.126217
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发表时间：
2020-06-01
期刊：
影响因子：
8.8
通讯作者：
Sugita, Haruo
中科院分区：
文献类型：
--
作者：
Itoi, Shiro;Sato, Tatsunori;Sugita, Haruo
河豚毒素(TTX)是一种强效神经毒素，广泛存在于多种系统发育不同的类群中。在海洋环境中，河豚在携带TTX的生物体中处于食物链的顶端。河豚体内TTX的积累似乎是从细菌开始的食物网。众所周知，有毒河豚在仔鱼/幼鱼阶段就有TTX。然而，TTX的来源不明，因为母源TTX的数量极少。因此，河豚毒素必须从其他生物或直接从环境中获得。在这里，我们报告了有毒鱼苗的TTX来源的证据，包括河豚(Cheronodon Patoca)和虎鱼(Yongeichthys Criniger)，从它们的肠道内容物可以看出，它们的来源是食物有机体。对线粒体COI基因的下一代测序分析表明，从这些有毒鱼类的肠道内容物中提取的大部分序列属于多突平线虫，这是一种多壳扁虫，含有来自幼虫阶段的高度浓缩的TTX。多发性棘球绦虫特异的聚合酶链式反应还显示，在虎鱼和河豚幼鱼的肠道内容物中强烈检测到编码大斑鱼COI基因的DNA。此外，在从TTX鱼类采样点周围的水中收集的环境海水中检测到了浮游生物特有的COI序列。这些结果表明，带TTX的鱼种幼鱼的主要TTX供给体是其幼虫。(C)2020爱思唯尔有限公司。保留所有权利。
Tetrodotoxin (TTX), a potent neurotoxin, is found in various phylogenetically diverse taxa. In marine environments, the pufferfish is at the top of the food chain among TTX-bearing organisms. The accumulation of TTX in the body of pufferfish appears to be of the food web that begins with bacteria. It is known that toxic pufferfishes possess TTX from the larval/juvenile stage. However, the source of the TTX is unknown because the maternally sourced TTX is extremely small in quantity. Therefore, the TTX has to be obtained from other organisms or directly from the environment. Here, we report evidence that the source of TTX for toxic fish juveniles including the pufferfish (Chelonodon patoca) and the goby (Yongeichthys criniger) is in the food organisms, as seen in their gut contents. Next generation sequencing analysis for the mitochondrial COI gene showed that the majority of the sequence recovered from intestinal contents of these toxic fishes belonged to the flatworm Planocera multitentaculata, a polyclad flatworm containing highly concentrated TTX from the larval stage. PCR specific to P. multitentaculata also showed that DNA encoding the planocerid COI gene was strongly detected in the intestinal contents of the goby and pufferfish juveniles. Additionally, the planocerid specific COI sequence was detected in the environmental seawater collected from the water around the sampling locations for TTX-bearing fish. These results suggest that planocerid larvae are the major TTX supplier for juveniles of TTX-bearing fish species. (C) 2020 Elsevier Ltd. All rights reserved.