New Insights on Cytological and Metabolic Features of Ostreopsis cf. ovata Fukuyo (Dinophyceae): A Multidisciplinary Approach
New Insights on Cytological and Metabolic Features of Ostreopsis cf. ovata Fukuyo (Dinophyceae): A Multidisciplinary Approach
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DOI：
10.1371/journal.pone.0057291
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发表时间：
2013-02-27
期刊：
影响因子：
3.7
通讯作者：
Tubaro, Aurelia
中科院分区：
文献类型：
--
作者：
Honsell, Giorgio;Bonifacio, Alois;Tubaro, Aurelia
有害甲藻Ostreopsis cf.OVATA一直在地中海沿岸和其他温带和热带地区造成中毒事件，在过去十年中频率越来越高。尽管进行了许多研究，但该物种的重要生物学特征仍鲜为人知。利用不同的显微镜和分子技术、拉曼光谱和高分辨液质联用(HR LC-MS)进行了综合研究，以阐明细胞学方面的内容，并鉴定包括毒素在内的主要代谢物。该种经遗传鉴定为O.cf.卵形，大西洋-地中海分支。超微结构结果显示了该物种大量产生的粘液网络的独特特征，以定居海底底物，具有以前从未描述过的毛囊的新作用。粘液的无定形多糖组分似乎来源于粘液纤维物质和粘液囊。在生长的所有阶段，细胞都显示出大量的脂类产生。不同发育阶段的叶绿体存在于细胞质的外围和细胞的中心。在活体拉曼光谱证实了类胡萝卜素Peridinin在O.cf.并在几个样品中检测到大量结构上与二十二碳六烯酸相关的不饱和脂肪的存在。HR LC-MS分析表明，卵毒素-a是主要的毒素，同时还有少量的卵毒素-b、-d/e、-c和推测的孢子虫毒素。每个细胞的毒素浓度从指数阶段增加到衰老阶段。结果表明，该物种的底栖生物水华可能与一些特征有关，如产生覆盖在海底的独特粘性鞘的能力，以及与产生类似孢子虫毒素的强烈毒素有关的能力。这样，O.cf.卵形动物可能会比其他物种更快地在底栖生物底物上定居。
The harmful dinoflagellate Ostreopsis cf. ovata has been causing toxic events along the Mediterranean coasts and other temperate and tropical areas, with increasing frequency during the last decade. Despite many studies, important biological features of this species are still poorly known. An integrated study, using different microscopy and molecular techniques, Raman microspectroscopy and high resolution liquid chromatography-mass spectrometry (HR LC-MS), was undertaken to elucidate cytological aspects, and identify main metabolites including toxins. The species was genetically identified as O. cf. ovata, Atlantic-Mediterranean clade. The ultrastructural results show unique features of the mucilage network abundantly produced by this species to colonize benthic substrates, with a new role of trichocysts, never described before. The amorphous polysaccharidic component of mucilage appears to derive from pusule fibrous material and mucocysts. In all stages of growth, the cells show an abundant production of lipids. Different developmental stages of chloroplasts are found in the peripheral cytoplasm and in the centre of cell. In vivo Raman microspectroscopy confirms the presence of the carotenoid peridinin in O. cf. ovata, and detects in several specimen the abundant presence of unsaturated lipids structurally related to docosahexaenoic acid. The HR LC-MS analysis reveals that ovatoxin-a is the predominant toxin, together with decreasing amounts of ovatoxin-b, -d/e, -c and putative palytoxin. Toxins concentration on a per cell basis increases from exponential to senescent phase. The results suggest that benthic blooms of this species are probably related to features such as the ability to create a unique mucilaginous sheath covering the sea bottom, associated with the production of potent toxins as palytoxin-like compounds. In this way, O. cf. ovata may be able to rapidly colonize benthic substrates outcompeting other species.