On paralytic shellfish poisoning producing capacity of <italic>Alexandrium tamarense</italic>

Abstract

In order to explore the capacity of paralytic shellfish poisoning (PSP) production in <italic>Alexandrium tamarense</italic>, the algae strain was cultivated in different space volumes, salinities and nutrient concentrations with controlling other conditions unchanged. After culturing for a period of time, a certain number of algal cells were collected by centrifugation to analyze and calculate the toxin content and profiles by liquid chromatography tandem-mass spectrometry (LC-MS/MS). Results showed that: 1) <italic>A</italic>. <italic>tamarense</italic> could produce at least 13 PSP components, of which the main components were GTX1,GTX4, GTX5, C1 and C2, accounting for 97.2% of the total toxin content, and the content of GTX1 was as high as 40%. At the same time, there was a significant difference in the minimum number of <italic>A</italic>. <italic>tamarense</italic> cells required for extraction and the quantitative detection of each component. For example, when the number of algal cells used to extract and analyze toxin profiles was less than 4×10³, none of the 13 PSP components could be quantitatively detected. When the number of algae cells used to extract and analyze toxin profiles was between 4×10³ and 5.9×10⁶, only part of the toxin components could be quantitatively detected. All these 13 PSP components could be quantified only when the number of algae cells used to extract and analyze toxin profiles was higher than 5.9×10⁶. 2) The PSP producing capacity of <italic>A</italic>.<italic>tamarense</italic> cultured in salinity 25 and 35 was significantly higher than that cultured in salinity 15, the PSP producing capacity of <italic>A</italic>. <italic>tamarense</italic> cultured in the flask of 1 L was significantly higher than that cultured in the flask of 0.1 L, and cultured in the oligotrophic group was significantly higher than that cultured in the eutrophic group. From these results, we could know that <italic>A</italic>. <italic>tamarense</italic> had a rich toxin profile, and contained at least 13 PSP toxin components with known structures. <italic>A</italic>.<italic>tamarense</italic> could be used for basic research of PSP toxin, and it was also the best theoretical algae strain for separating and extracting GTX1. It showed stronger capacity of PSP production when cultivated in the flask of 1 L, at the salinity of 25 and 1/4 times of the f/2 medium concentration. <italic>A</italic>.<italic>tamarense</italic> blooms with high PSP toxicity may occur in marine environments with high salinity, sufficient space and high eutrophication. Thus, in order to reduce the risk of harmful <italic>A</italic>.<italic>tamarense</italic> blooms with high PSP toxicity, the supervision of sea areas that meet the above conditions should be strengthened carefully.