Department of Zoology and Plankton Ecology and Limnology Laboratory, Biological Station, University of Oklahoma, Norman, OK, USA.
Ecol Lett. 2012 Feb;15(2):126-32. doi: 10.1111/j.1461-0248.2011.01718.x. Epub 2011 Dec 2.
Blooms of Prymnesium parvum can severely harm fish and zooplankton, presumably through the release of allelopathic exotoxins that offer advantages for Prymnesium in its interactions with competitors and prey. We show that Prymnesium attaches to zooplankton and fish, causing mortality, whereas exposure of these organisms to Prymnesium across a permeable membrane does not cause mortality. We also show that Prymnesium exotoxins are released independently of contact toxicity only in response to experimental procedures or natural causes of stress. Our results are consistent with the idea that toxins have evolved for release during cell-to-cell contact in support of heterotrophy. The evolution of toxin-assisted micropredation would be consistent with mechanisms of natural selection favouring individual fitness as opposed to broadcast allelopathy from which the benefits are more dispersed. Research into the toxicity of Prymnesium and other harmful algal species may profit from focus on processes following physical contact with potential prey.
绿色巴夫藻大量繁殖会严重危害鱼类和浮游动物，可能是通过释放化感外毒素实现的，这种毒素有利于绿色巴夫藻在与竞争者和猎物的相互作用中胜出。我们发现绿色巴夫藻会附着在浮游动物和鱼类上，导致其死亡，而这些生物暴露在可渗透膜另一侧的绿色巴夫藻中则不会死亡。我们还发现，只有在接触毒性以外的情况下，例如受到实验程序或自然胁迫的影响，绿色巴夫藻才会独立释放毒素。我们的研究结果表明，毒素是为了在细胞间接触时释放而进化的，这有助于绿色巴夫藻实现异养。毒素辅助的微捕食的进化与自然选择机制是一致的，这种机制有利于个体的适应性，而不是化感作用这种利益更为分散的繁殖方式。对绿色巴夫藻和其他有害藻类物种的毒性研究可能会受益于关注与潜在猎物发生物理接触后的过程。
