Dang Lin-Xi, Li Yue, Liu Fei, Zhang Yong, Yang Wei-Dong, Li Hong-Ye, Liu Jie-Sheng
College of Life Sciences and Technology, Jinan University, Guangzhou, 510632, China.
Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Guangzhou, 510632, China.
J Eukaryot Microbiol. 2015 Jul-Aug;62(4):470-80. doi: 10.1111/jeu.12201. Epub 2015 Jan 6.
We investigated the toxicity of Karenia mikimotoi toward three model grazers, the cladoceran Moina mongolica, the copepod Pseudodiaptomus annandalei, and the crustacean Artemia salina, and explored its chemical response upon zooplankton grazing. An induction experiment, where K. mikimotoi was exposed to grazers or waterborne cues from the mixed cultures revealed that K. mikimotoi might be toxic or nutritionally inadequate toward the three grazers. In general, direct exposure to the three grazers induced the production of hemolytic toxins and the synthesis of eicosapentaenoic acid (EPA). Both EPA and the hemolytic toxins from K. mikimotoi decreased the survival rate of the three grazers. In addition, the survival rates of M. mongolica, P. annandalei, and A. salina in the presence of induced K. mikimotoi that had previously been exposed to a certain grazer were lower than their counterparts caused by fresh K. mikimotoi, suggesting that exposure to some grazers might increase the toxicity of K. mikimotoi. The chemical response and associated increased resistance to further grazing suggested that K. mikimotoi could produce deterrents to protect against grazing by zooplankton and that the substances responsible might be hemolytic toxins and EPA.
我们研究了米氏凯伦藻对三种模式食草动物的毒性，即枝角类蒙古裸腹溞、桡足类安南伪镖水蚤和甲壳类卤虫，并探讨了其对浮游动物摄食的化学反应。在一项诱导实验中，将米氏凯伦藻暴露于食草动物或混合培养物的水体线索中，结果表明米氏凯伦藻对这三种食草动物可能有毒或营养不足。一般来说，直接暴露于这三种食草动物会诱导溶血毒素的产生和二十碳五烯酸（EPA）的合成。米氏凯伦藻产生的EPA和溶血毒素均降低了这三种食草动物的存活率。此外，在存在先前暴露于特定食草动物的诱导米氏凯伦藻的情况下，蒙古裸腹溞、安南伪镖水蚤和卤虫的存活率低于由新鲜米氏凯伦藻导致的存活率，这表明暴露于某些食草动物可能会增加米氏凯伦藻的毒性。化学反应以及对进一步摄食的相关抗性增加表明，米氏凯伦藻可以产生威慑物以防止浮游动物的摄食，而负责的物质可能是溶血毒素和EPA。
