Lethal effects of ichthyotoxic raphidophytes, Chattonella marina, C. antiqua, and Heterosigma akashiwo, on post-embryonic stages of the Japanese pearl oyster, Pinctada fucata martensii
Lethal effects of ichthyotoxic raphidophytes, Chattonella marina, C. antiqua, and Heterosigma akashiwo, on post-embryonic stages of the Japanese pearl oyster, Pinctada fucata martensii
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DOI：
10.1016/j.hal.2016.08.003
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发表时间：
2016-11-01
期刊：
影响因子：
6.6
通讯作者：
Nagai, Satoshi
中科院分区：
文献类型：
--
作者：
Basti, Leila;Nagai, Kiyohito;Nagai, Satoshi
研究了赤潮形成的异弯藻、Chattonella marina和Chattonella antiqua对合浦珠母贝（Pinctada fucata martensii）早期生长的影响。受精卵和发育中的胚胎没有受到影响后，暴露于有害的针藻类，但是，所有三种藻类严重影响担轮藻和D-幼虫，早期D-幼虫，后期预沉淀幼虫。暴露于C。marina（5 × 10（2）cells ml（-1））、C antigun（10（3）cells ml（-1））和H. Akashiwo（5 × 10（3）细胞ml（-1））导致变态到担轮幼虫阶段的成功率降低。在5 × 10 ~（3）cells ml ~（-1）浓度下，C. antiqua和C. marina在8 × 10（3）细胞ml（-1）。在所有的实验中，超过80%的新形成的担轮柄是异常的，在暴露于H。在10（5）cells ml（-1）浓度下，70%以上的D-幼虫表现异常。D型幼虫（1日龄）经8 × 10 ~（3）cells ml ~（-1），24 h后，其活动率显著降低; marina（8 × 10 ~（3）cells ml ~（-1），24 h）和H. akashiwo（10（4）cells ml（-1），24 h）。预沉幼虫（21日龄）的活动率在暴露于C. antiqua（10（3）cells ml（-1），24 h），C. marina（8 × 10 ~（3）cells ml ~（-1），24 h）和H. akashiwo（5 × 10（4）细胞ml（-1），24 h）。这两个幼虫阶段的显着死亡率诱导所有三个针芽植物，与更高的死亡率登记预沉降幼虫比D-幼虫，特别是在暴露于C。marina（5 × 10（2）~ 8 × 10（3）cells ml（-1），48-86 h）和C. antiqua（10（3）-8 × 10（3）cells ml（-1），72-86 h）。针形藻细胞和新变态的担轮藻和D-幼虫，1天大的D-幼虫，和21天大的幼虫之间的接触导致针形藻的微观变化，然后，在能动的早期阶段的珍珠牡蛎。当幼虫纤毛接触和物理干扰细胞时，H. akashiwo，C. marina和C. antiqua变得不动并脱落它们的糖萼。担轮体和幼虫被困在一个聚集的糖萼和粘液，最有可能的混合物幼虫粘液和针芽植物tricosyts和粘液细胞。所有的运动阶段的珍珠牡蛎幼虫表现出典型的逃避行为转化为增加游泳，努力释放自己的粘性粘液陷阱。幼虫随后变得筋疲力尽，陷入更重的粘液中，失去幼虫纤毛，下沉，变得不动，然后死亡。虽然其他有毒介质可能已经参与，本研究的结果表明，所有三个针孢是有害的，只有运动阶段的珍珠牡蛎，和物理干扰的细胞接触后，与纤毛结构的珍珠牡蛎幼虫启动的有害机制。本研究首次报道了有害的查顿氏菌的致死作用。一种双壳类软体动物的幼虫H的花朵akashiwo，C. antiqua和C.因此，日本珠母贝在其早期生命活动阶段的暴露可能对其种群补充产生不利影响。此外，目前的研究表明，进一步研究珍珠牡蛎和其他双壳类的早期生命发育可能有助于提高对有争议的有害机制的理解。(C)2016爱思唯尔B. V.保留所有权利。
The inimical effects of the ichthyotoxic harmful algal bloom (HAB)-forming raphidophytes Heterosigma akashiwo, Chattonella marina, and Chattonella antiqua on the early-life stages of the Japanese pearl oyster Pinctada fucata martensii were studied. Fertilized eggs and developing embryos were not affected following exposure to the harmful raphidophytes; however, all three algal species severely affected trochophores and D-larvae, early-stage D-larvae, and late-stage pre-settling larvae. Exposure to C. marina (5 x 10(2) cells ml(-1)), C antigun (10(3) cells ml(-1)), and H. akashiwo (5 x 10(3) cells ml(-1)) resulted in decreased success of metamorphosis to the trochophore stage. A complete inhibition of trochophore metamorphosis was observed following exposure to C antiqua at 5 x 10(3) cells ml(-1) and C. marina at 8 x 10(3) cells ml(-1). In all experiments, more than 80% of newly formed trochophores were anomalous, and in the case of exposure to H. akashiwo at 10(5) cells ml(-1) more than 70% of D-larvae were anomalous. The activity rates of D-larvae (1-day-old) were significantly reduced following exposure to C antiqua (8 x 10(3) cells ml(-1), 24 h), C. marina (8 x 10(3) cells ml(-1), 24 h), and H. akashiwo (10(4) cells ml(-1), 24 h). The activity rates of pre-settling larvae (21-day-old) were also significantly reduced following exposure to C. antiqua (10(3) cells ml(-1), 24 h), C. marina (8 x 10(3) cells ml(-1), 24 h), and H. akashiwo (5 x 10(4) cells ml(-1), 24 h). Significant mortalities of both larval stages were induced by all three raphidophytes, with higher mortality rates registered for pre-settling larvae than D-larvae, especially following exposure to C. marina (5 x 10(2)-8 x 10(3) cells ml(-1), 48-86 h) and C. antiqua (10(3)-8 x 10(3) cells ml(-1), 72-86 h). Contact between raphidophyte cells and newly metamorphosed trochophores and D-larvae, 1-day-old D-larvae, and 21-day-old larvae resulted in microscopic changes in the raphidophytes, and then, in the motile early-life stages of pearl oysters. Upon contact and physical disturbance of their cells by larval cilia, H. akashiwo, C. marina and C. antiqua became immotile and shed their glycocalyx. The trochophores and larvae were observed trapped in a conglomerate of glycocalyx and mucus, most probably a mixture of larval mucous and raphidophyte tricosyts and mucocytes. All motile stages of pearl oyster larvae showed a typical escape behavior translating into increased swimming in an effort to release themselves from the sticky mucous traps. The larvae subsequently became exhausted, entrapped in more heavy mucous, lost their larval cilia, sank, become immotile, and died. Although other toxic mediators could have been involved, the results of the present study indicate that all three raphidophytes were harmful only for motile stages of pearl oysters, and that the physical disturbance of their cells upon contact with the ciliary structures of pearl oyster larvae initiated the harmful mechanism. The present study is the first report of lethal effects of harmful Chattonella spp. towards larvae of a bivalve mollusc. Blooms of H. akashiwo, C. antiqua and C. marina occur in all major cultivation areas of P. fucata martensii during the developmental period of their larvae.Therefore, exposure of the motile early-life stages of Japanese pearl oysters could adversely affect their population recruitment. In addition, the present study shows that further research with early-life development of pearl oysters and other bivalves could contribute to improving the understanding of the controversial harmful mechanisms of raphidophytes in marine organisms. (C) 2016 Elsevier B.V. All rights reserved.