Key Laboratory of Environment Change and Resources Use in Beibu Gulf, Ministry of Education, Nanning Normal University, Nanning 530001, China.
Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Guangxi University, Nanning 530004, China.
Toxins (Basel). 2021 Feb 18;13(2):161. doi: 10.3390/toxins13020161.
The frequency of harmful algal blooms (HABs) has increased in China in recent years. Information about harmful dinoflagellates and paralytic shellfish toxins (PSTs) is still limited in China, especially in the Beibu Gulf, where PSTs in shellfish have exceeded food safety guidelines on multiple occasions. To explore the nature of the threat from PSTs in the region, eight strains were isolated from waters of the Beibu Gulf and examined using phylogenetic analyses of large subunit (LSU) rDNA, small subunit (SSU) rDNA, and internal transcribed spacer (ITS) sequences. Their toxin composition profiles were also determined using liquid chromatography-tandem mass spectrometry (LC-MS/MS). All eight strains clustered in the phylogenetic tree with , , and from other locations, forming three well-resolved groups. The intraspecific genetic distances of the three species were significantly smaller than interspecific genetic distances for species. Beibu Gulf isolates were therefore classified as , , and . No PSTs were identified in , but low levels of gonyautoxins (GTXs) 1 to 5, and saxitoxin (STX) were detected in (a total of 4.60 fmol/cell). The extremely low level of toxicity is inconsistent with PST detection above regulatory levels on multiple occasions within the Beibu Gulf, suggesting that higher toxicity strains may occur in those waters, but were unsampled. Other explanations including biotransformation of PSTs in shellfish and the presence of other PST-producing algae are also suggested. Understanding the toxicity and phylogeny of species provides foundational data for the protection of public health in the Beibu Gulf region and the mitigation of HAB events.
近年来，中国有害藻华（HAB）的频率有所增加。中国有关有害甲藻和麻痹性贝类毒素（PSTs）的信息仍然有限，特别是在北部湾，贝类中的 PSTs 多次超过食品安全标准。为了探索该地区 PSTs 威胁的性质，从北部湾水域分离了 8 株，并通过大亚基（LSU）rDNA、小亚基（SSU）rDNA 和内部转录间隔区（ITS）序列的系统发育分析对其进行了研究。还使用液相色谱-串联质谱（LC-MS/MS）测定了它们的毒素组成谱。这 8 株菌在系统发育树中与来自其他地区的 、 和 聚类，形成了三个明确的组。三种 的种内遗传距离明显小于 种间遗传距离。因此，北部湾分离株被分类为 、 和 。在 中未鉴定出 PSTs，但在 中检测到低水平的 GTXs 1 至 5 和石房蛤毒素（STX）（共 4.60 fmol/细胞）。极低的毒性与北部湾多次 PST 检测超过监管水平不一致，这表明这些水域可能存在毒性更高的菌株，但未被采样。其他解释包括贝类中 PSTs 的生物转化和其他产生 PST 的藻类的存在。了解 种的毒性和系统发育为保护北部湾地区的公众健康和减轻 HAB 事件提供了基础数据。
