CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
Harmful Algae. 2022 Mar;113:102188. doi: 10.1016/j.hal.2022.102188. Epub 2022 Feb 1.
Dinoflagellate Gymnodinium catenatum is an important producer of paralytic shellfish toxins (PSTs), including a novel group of hydroxybenzoate derivatives named GC toxins. In the East China Sea, G. catenatum has been considered as the causative agent for several paralytic shellfish poisoning (PSP) episodes, yet the knowledge on their toxin production was still quite limited. In this study, toxins produced by a strain of G. catenatum (MEL11) isolated from the East China Sea were determined, using high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). Changes of toxin profile in the stain MEL11 in response to nutrient and temperature variations were also examined. A total of 11 PST components dominated by hydroxybenzoate analogs and N-sulfocarbamoyl toxins were detected, which was different from other G. catenatum strains previously established in the East China Sea in the presence of GC5 and the lack of dcGTX2&3. Cellular toxin composition and content of the strain had no apparent change within a range of temperature from 20°C to 26°C. In contrast, nutrient limitation and nitrogen source had notable impacts on toxin production. The molar percentage of GC toxins decreased remarkably at the stationary growth phase under nutrient-deprived conditions of both nitrogen (N) and phosphorus (P). The replacement of nitrate with ammonium as the source of N significantly promoted PST production by G. catenatum. The study revealed the potential diversity of toxin profiles of G. catenatum in the East China Sea, and highlighted the effects of nutrients on production of GC toxins by G. catenatum.
甲藻属中的链状亚历山大藻是麻痹性贝类毒素（PSTs）的重要生产者，包括一组新型的羟基苯甲酸酯衍生物，名为 GC 毒素。在中国东海，链状亚历山大藻被认为是几次麻痹性贝类中毒（PSP）事件的病原体，但对其毒素产生的了解仍然相当有限。在这项研究中，使用高效液相色谱-串联质谱（HPLC-MS/MS）测定了从中国东海分离的链状亚历山大藻（MEL11）产生的毒素。还检查了 MEL11 菌株对营养和温度变化的毒素谱变化。检测到 11 种 PST 成分，主要由羟基苯甲酸类似物和 N-磺酰胺基毒素组成，这与以前在中国东海建立的其他链状亚历山大藻菌株不同，因为存在 GC5，缺乏 dcGTX2&3。在 20°C 至 26°C 的温度范围内，菌株的细胞毒素组成和含量没有明显变化。相比之下，营养限制和氮源对毒素产生有显著影响。在氮（N）和磷（P）两种营养物质都缺乏的静止生长阶段，GC 毒素的摩尔百分比显著下降。用铵代替硝酸盐作为氮源会显著促进链状亚历山大藻产生 PST。研究揭示了东海链状亚历山大藻毒素谱的潜在多样性，并强调了营养物质对链状亚历山大藻产生 GC 毒素的影响。
