Biotechnology, Department of Biochemistry, University of Turku, Tykistökatu 6 A 6th Floor, FI-20520 Turku, Finland.
VERIFIN - Finnish Institute for Verification of the Chemical Weapons Convention, Department of Chemistry, P.O. Box 55, FI-00014 University of Helsinki, Finland.
Harmful Algae. 2016 Feb;52:1-10. doi: 10.1016/j.hal.2015.10.018. Epub 2015 Dec 23.
Many marine dinoflagellates, including several species of the genus Alexandrium, Gymnodinium catenatum, and Pyrodinium bahamense are known for their capability to produce paralytic shellfish toxins (PST), which can cause severe, most often food-related poisoning. The recent discovery of the first PST biosynthesis genes has laid the foundation for the development of molecular detection methods for monitoring and study of PST-producing dinoflagellates. In this study, a probe-based qPCR method for the detection and quantification of the sxtA4 gene present in Alexandrium spp. and Gymnodinium catenatum was designed. The focus was on Alexandrium ostenfeldii, a species which recurrently forms dense toxic blooms in areas within the Baltic Sea. A consistent, positive correlation between the presence of sxtA4 and PST biosynthesis was observed, and the species was found to maintain PST production with an average of 6 genomic copies of sxtA4. In August 2014, A. ostenfeldii populations were studied for cell densities, PST production, as well as sxtA4 and species-specific LSU copy numbers in Föglö, Åland, Finland, where an exceptionally dense bloom, consisting of 6.3×10cellsL, was observed. Cell concentrations, and copy numbers of both of the target genes were positively correlated with total STX, GTX2, and GTX3 concentrations in the environment, the cell density predicting toxin concentrations with the best accuracy (Spearman's ρ=0.93, p<0.01). The results indicated that all A. ostenfeldii cells in the blooms harbored the genetic capability of PST production, making the detection of sxtA4 a good indicator of toxicity.
许多海洋甲藻，包括亚历山大藻属的几个物种、链状亚历山大藻和短凯伦藻，都以产生麻痹性贝类毒素 (PST) 的能力而闻名，这些毒素会导致严重的、通常与食物有关的中毒。最近发现的第一批 PST 生物合成基因为监测和研究产 PST 甲藻的分子检测方法奠定了基础。在这项研究中，设计了一种基于探针的 qPCR 方法，用于检测和定量存在于亚历山大藻属和链状亚历山大藻中的 sxtA4 基因。研究重点是亚历山大藻，一种在波罗的海区域反复形成密集有毒水华的物种。观察到 sxtA4 的存在与 PST 生物合成之间存在一致的正相关，并且该物种维持 PST 生产的平均 sxtA4 基因拷贝数为 6 个。2014 年 8 月，在芬兰奥兰群岛的 Föglö 研究了亚历山大藻种群的细胞密度、PST 产生以及 sxtA4 和种特异性 LSU 拷贝数，在那里观察到异常密集的水华，由 6.3×10 个细胞/L 组成。细胞浓度和两个目标基因的拷贝数与环境中的总 STX、GTX2 和 GTX3 浓度呈正相关，细胞密度对毒素浓度的预测具有最佳准确性（Spearman's ρ=0.93，p<0.01）。结果表明，水华中的所有亚历山大藻细胞都具有 PST 产生的遗传能力，因此检测 sxtA4 是毒性的良好指标。
