Costa Pedro Reis, Moita Teresa, Rodrigues Susana Margarida
IPMA - Intituto Português do Mar e da Atmosfera, Av. Brasília, 1449-006 Lisbon, Portugal.
IPMA - Intituto Português do Mar e da Atmosfera, Av. Brasília, 1449-006 Lisbon, Portugal.
Harmful Algae. 2014 Jan;31:35-40. doi: 10.1016/j.hal.2013.09.009. Epub 2013 Oct 17.
Gymnodinium catenatum, a dinoflagellate species with a global distribution, is known to produce paralytic shellfish poisoning (PSP) toxins. The profile of toxins of G. catenatum is commonly dominated by sulfocarbamoyl analogs including the C3+4 and GTX6, which to date has no commercial certified reference materials necessary for their quantification via chemical methods, such as liquid chromatography. The aim of this study was to assess the presence of C3+4 and GTX6 and their contribution to shellfish toxicity. C3+4 and GTX6 were indirectly quantified via pre-column oxidation liquid chromatography with fluorescence detection after hydrolysis conversion into their carbamate analogs. Analyses were carried out in mussel samples collected over a bloom of G. catenatum (>63×10cellsl) in Aveiro lagoon, NW Portuguese coast. Concentration levels of sulfocarbamoyl toxin analogs were two orders of magnitude higher than decarbamoyl toxins, which were in turn one order of magnitude higher than carbamoyl toxins. Among the sulfocarbamoyl toxins, C1+2 were clearly the dominant compounds, followed by C3+4 and GTX6. The least abundant sulfocarbamoyl toxin was GTX5. The most important compounds in terms of contribution for sample toxicity were C1+2, which justified 26% of the PSP toxicity. The lesser abundant dcSTX constitutes the second most important compound with similar % of toxicity to C1+2, C3+4 and GTX6 were responsible for approximately 11% and 13%, respectively. The median of the sum of C3+4 and GTX6 was 27%. These levels reached a maximum of 60% as was determined for the sample collected closest to the G. catenatum bloom. This study highlights the importance of these low potency PSP toxin analogs to shellfish toxicity. Hydrolysis conversion of C3+4 and GTX6 is recommended for determination of PSP toxicity when LC detection methods are used for PSP testing in samples exposed to G. catenatum.
链状裸甲藻是一种分布于全球的甲藻物种，已知其会产生麻痹性贝类毒素（PSP）。链状裸甲藻的毒素谱通常以包括C3 + 4和GTX6在内的磺基氨基甲酰类似物为主，迄今为止，尚无通过化学方法（如液相色谱法）对其进行定量所需的商业认证参考物质。本研究的目的是评估C3 + 4和GTX6的存在及其对贝类毒性的贡献。在水解转化为其氨基甲酸酯类似物后，通过柱前氧化液相色谱-荧光检测间接定量C3 + 4和GTX6。对在葡萄牙西北海岸阿威罗泻湖链状裸甲藻大量繁殖（>63×10个细胞/升）期间采集的贻贝样本进行了分析。磺基氨基甲酰毒素类似物的浓度水平比脱氨基甲酰毒素高两个数量级，而脱氨基甲酰毒素又比氨基甲酰毒素高一个数量级。在磺基氨基甲酰毒素中，C1 + 2显然是主要化合物，其次是C3 + 4和GTX6。含量最少的磺基氨基甲酰毒素是GTX5。就对样本毒性的贡献而言，最重要的化合物是C1 + 2，其导致了26%的PSP毒性。含量较少的dcSTX是第二重要的化合物，其毒性百分比与C1 + 2相似，C3 + 4和GTX6分别导致了约11%和13%的毒性。C3 + 4和GTX6总和的中位数为27%。对于最接近链状裸甲藻大量繁殖区域采集的样本，这些水平最高达到了60%。本研究强调了这些低毒PSP毒素类似物对贝类毒性的重要性。当使用液相色谱检测方法对暴露于链状裸甲藻的样本进行PSP检测时，建议对C3 + 4和GTX6进行水解转化以测定PSP毒性。
