The neurotoxin β-N-methylamino-L-alanine (BMAA), produced by cyanobacteria and diatoms, has been implicated as an environmental risk factor for neurodegenerative diseases. This study first investigated the occurrence and monthly distributions of BMAA and its isomers, 2,4-diaminobutyric acid (DAB) and N-2-aminoethylglycine (AEG), in phytoplankton and mussels from 11 sites along the South Sea Coast of Korea throughout 2021. These toxins were quantified using LC-MS/MS, revealing elevated BMAA concentrations from late autumn to spring, with phase lags observed between phytoplankton and mussels. The highest concentration of BMAA in phytoplankton was detected in November (mean: 1490 ng g dry weight (dw)), while in mussels, it peaked in December (mean: 1240 ng g dw). DAB was detected in phytoplankton but was absent in mussels, indicating limited bioaccumulation potential. In February, the peak mean DAB concentration in phytoplankton was 89 ng g dw. AEG was not detected in any samples. Chlorophyll-a concentrations consistently showed an inverse correlation with BMAA concentrations in mussels throughout the year. Through correlation analysis, four diatom genera, , , , and , were identified as potential causative microalgae of BMAA. This study offers insights into identifying the causative microalgae for BMAA and informs future regulatory efforts regarding unmanaged biotoxins.

中文翻译：

---

首次调查韩国南海沿岸神经毒素 β-N-甲氨基-L-丙氨酸 (BMAA) 和候选致病微藻的时间分布


由蓝细菌和硅藻产生的神经毒素 β-N-甲氨基-L-丙氨酸 (BMAA) 被认为是神经退行性疾病的环境危险因素。本研究首先调查了 2021 年韩国南海沿岸 11 个地点的浮游植物和贻贝中 BMAA 及其异构体 2,4-二氨基丁酸 (DAB) 和 N-2-氨乙基甘氨酸 (AEG) 的出现情况和每月分布情况使用 LC-MS/MS 对这些毒素进行定量，显示从深秋到春季，BMAA 浓度升高，并且在浮游植物和贻贝之间观察到相位滞后。浮游植物中 BMAA 的最高浓度出现在 11 月份（平均值：1490 ng g 干重 (dw)），而贻贝的 BMAA 浓度在 12 月份达到峰值（平均值：1240 ng g dw）。在浮游植物中检测到 DAB，但在贻贝中不存在，表明生物累积潜力有限。 2 月份，浮游植物中 DAB 平均峰值浓度为 89 ng g dw。在任何样品中均未检测到 AEG。全年贻贝中的叶绿素-a 浓度始终与 BMAA 浓度呈负相关。通过相关性分析，确定了 、 、 、 和 4 个硅藻属为 BMAA 的潜在致病微藻。这项研究为识别 BMAA 的致病微藻提供了见解，并为未来有关未管理的生物毒素的监管工作提供了信息。