Institute for Marine Biosciences, National Research Council of Canada, 1411 Oxford Street, Halifax, NS B3H 3Z1, Canada.
Institute for Marine Biosciences, National Research Council of Canada, 1411 Oxford Street, Halifax, NS B3H 3Z1, Canada; Measurement Science and Standards, National Research Council of Canada, 1411 Oxford Street, Halifax, NS B3H 3Z1, Canada.
Harmful Algae. 2017 Mar;63:85-93. doi: 10.1016/j.hal.2017.01.012. Epub 2017 Feb 11.
Many toxic secondary metabolites used for defense are also toxic to the producing organism. One important way to circumvent toxicity is to store the toxin as an inactive precursor. Several sulfated diesters of the diarrhetic shellfish poisoning (DSP) toxin okadaic acid have been reported from cultures of various dinoflagellate species belonging to the genus Prorocentrum. It has been proposed that these sulfated diesters are a means of toxin storage within the dinoflagellate cell, and that a putative enzyme mediated two-step hydrolysis of sulfated diesters such as DTX-4 and DTX-5 initially leads to the formation of diol esters and ultimately to the release of free okadaic acid. However, only one diol ester and no sulfated diesters of DTX-1, a closely related DSP toxin, have been isolated leading some to speculate that this toxin is not stored as a sulfated diester and is processed by some other means. DSP components in organic extracts of two large scale Prorocentrum lima laboratory cultures have been investigated. In addition to the usual suite of okadaic acid esters, as well as the free acids okadaic acid and DTX-1, a group of corresponding diol- and sulfated diesters of both okadaic acid and DTX-1 have now been isolated and structurally characterized, confirming that both okadaic acid and DTX-1 are initially formed in the dinoflagellate cell as the non-toxic sulfated diesters.
许多用于防御的有毒次生代谢物对产生它们的生物体也是有毒的。一种避免毒性的重要方法是将毒素储存为无活性的前体。已从属于原甲藻属的各种甲藻物种的培养物中报道了几种腹泻性贝类毒素（DSP）毒素 okadaic 酸的硫酸二酯。有人提出，这些硫酸二酯是甲藻细胞内毒素储存的一种方式，并且假定酶介导的两步水解硫酸二酯（如 DTX-4 和 DTX-5）最初导致二醇酯的形成，最终导致游离 okadaic 酸的释放。然而，只有一种二醇酯和一种与 DSP 毒素密切相关的 DTX-1 的硫酸二酯被分离出来，这使得一些人推测这种毒素不是作为硫酸二酯储存的，而是通过其他一些方式进行处理的。已对两种大规模原甲藻 lima 实验室培养物的有机提取物中的 DSP 成分进行了研究。除了通常的 okadaic 酸酯套件，以及游离酸 okadaic 酸和 DTX-1 外，现在已经分离并结构表征了一组 okadaic 酸和 DTX-1 的相应二醇酯和硫酸二酯，证实 okadaic 酸和 DTX-1 最初都是在甲藻细胞中形成的非毒性硫酸二酯。
