Ifremer, Phycotoxins Laboratory, rue de l'Ile d'Yeu, BP 21105, F-44311 Nantes, France.
National Oceanic and Atmospheric Administration, National Ocean Service, National Centers for Coastal Ocean Science, Center for Coastal Fisheries and Habitat Research (CCFHR),101 Pivers Island Road, Beaufort, NC 28516, USA.
Harmful Algae. 2017 Mar;63:173-183. doi: 10.1016/j.hal.2017.02.005. Epub 2017 Mar 9.
Species in the epi-benthic dinoflagellate genus Gambierdiscus produce ciguatoxins (CTXs) and maitotoxins (MTXs), which are among the most potent marine toxins known. Consumption of fish contaminated with sufficient quantities of CTXs causes Ciguatera Fish Poisoning (CFP), the largest cause of non-bacterial food poisoning worldwide. Maitotoxins, which can be found in the digestive system of fish, could also contribute to CFP if such tissues are consumed. Recently, an increasing number of Gambierdiscus species have been identified; yet, little is known about the variation in toxicity among Gambierdiscus strains or species. This study is the first assessment of relative CTX- and MTX-toxicity of Gambierdiscus species from areas as widespread as the North-Eastern Atlantic Ocean, Pacific Ocean and the Mediterranean Sea. A total of 13 strains were screened: (i) seven Pacific strains of G. australes, G. balechii, G. caribaeus, G. carpenteri, G. pacificus, G. scabrosus and one strain of an undetermined species (Gambierdiscus sp. Viet Nam), (ii) five strains from the North-Eastern Atlantic Ocean (two G. australes, a single G. excentricus and two G. silvae strains), and (iii) one G. carolinianus strain from the Mediterranean Sea. Cell pellets of Gambierdiscus were extracted with methanol and the crude extracts partitioned into a CTX-containing dichloromethane fraction and a MTX-containing aqueous methanol fraction. CTX-toxicity was estimated using the neuro-2a cytoxicity assay, and MTX-toxicity via a human erythrocyte lysis assay. Different species were grouped into different ratios of CTX- and MTX-toxicity, however, the ratio was not related to the geographical origin of species (Atlantic, Mediterranean, Pacific). All strains showed MTX-toxicity, ranging from 1.5 to 86pg MTX equivalents (eq) cell. All but one of the strains showed relatively low CTX-toxicity ranging from 0.6 to 50 fg CTX3C eq cell. The exception was the highly toxic G. excentricus strain from the Canary Islands, which produced 1426 fg CTX3C eq cell. As was true for CTX, the highest MTX-toxicity was also found in G. excentricus. Thus, the present study confirmed that at least one species from the Atlantic Ocean demonstrates similar toxicity as the most toxic strains from the Pacific, even if the metabolites in fish have so far been shown to be more toxic in the Pacific Ocean.
共生甲藻属的物种会产生雪卡毒素（CTXs）和鳗草毒素（MTXs），它们是已知最具毒性的海洋毒素之一。食用含有足够 CTXs 量的鱼会导致雪卡鱼中毒（CFP），这是全球最大的非细菌性食物中毒原因。如果食用鱼类的消化组织，鳗草毒素也可能导致 CFP。最近，已经鉴定出越来越多的共生甲藻属物种；然而，关于共生甲藻属菌株或物种之间的毒性变化知之甚少。本研究是对来自东北大西洋、太平洋和地中海等广泛地区的共生甲藻属物种的相对 CTX 和 MTX 毒性的首次评估。共筛选了 13 株：（i）7 株太平洋共生甲藻属菌株，包括 G. australes、G. balechii、G. caribaeus、G. carpenteri、G. pacificus、G. scabrosus 和一株未确定种的菌株（Viet Nam 共生甲藻属），（ii）5 株来自东北大西洋的菌株（2 株 G. australes、1 株 G. excentricus 和 2 株 G. silvae 菌株），和（iii）1 株来自地中海的 G. carolinianus 菌株。共生甲藻属细胞沉淀用甲醇提取，粗提物分为含有 CTX 的二氯甲烷部分和含有 MTX 的甲醇水溶液部分。使用神经-2a 细胞毒性测定法估计 CTX 毒性，用人红细胞溶血测定法测定 MTX 毒性。不同的物种被分为不同的 CTX 和 MTX 毒性比值，但比值与物种的地理来源（大西洋、地中海、太平洋）无关。所有菌株均表现出 MTX 毒性，范围从 1.5 到 86pg MTX 当量（eq）细胞。除一株外，所有菌株的 CTX 毒性均较低，范围从 0.6 到 50fg CTX3C eq 细胞。例外的是来自加那利群岛的高度毒性的 G. excentricus 菌株，其产生了 1426fg CTX3C eq 细胞。与 CTX 一样，毒性最高的也是 G. excentricus。因此，本研究证实，即使鱼类中的代谢物迄今为止在太平洋地区显示出更高的毒性，来自大西洋的至少一个物种也表现出与太平洋最毒菌株相似的毒性。
