Toxin composition and toxicity dynamics of marine gastropod Nassarius spp. collected from Lianyungang, China

Abstract

Consumption of nassariid gastropods often leads to poisoning incidents in some coastal provinces in China. To elucidate the pattern of toxicity dynamics and origin of toxins, samples of gastropod Nassarius spp. were collected from late May to early August 2007 from Lianyungang, Jiangsu province, where the poisoning incidents have been frequently reported. Toxicity was first screened with the mouse bioassay method, and tetrodotoxin and its analogues (TTXs) were analysed with high-performance liquid chromatography coupled with an ion-trap mass spectrometer (HPLC-MS ⁿ ). The toxicity of nassariid N. semiplicatus showed an ‘M’-shaped pattern of fluctuation during the sampling season. Two peaks of toxicity appeared in late May and late July. The maximum toxicity was recorded on 24 May, with the value of 846 mouse unit (MU) g⁻¹ of tissue (wet weight). TTX and its analogues trideoxyTTX, 4-epiTTX, anhydroTTX and oxoTTX were detected in the nassariid samples. TrideoxyTTX but not TTX was the major toxin in all the samples. No paralytic shellfish poison (PSP) was detected in the sample with the maximum toxicity by HPLC-FLD analysis. Variation of TTX content in the tissue of nassariid gastropods correlates well with the dynamics of toxicity. It is suggested that TTXs are the major toxins corresponding to the toxicity of the nassariids, and May and July are the high-risk seasons for consumption of nassariids, which is critical for the management of poisoning incidents.

Keywords:

• seafood
• natural toxicants
• chromatography – LC/MS
• bioassay

Acknowledgements

This work was supported by the projects (40821004 and 30571426) from the Natural Science Foundation of China (NSFC) and a project (KZCX2-YW-Q07-04) from the Chinese Academy of Sciences. It was also supported partially by a knowledge innovation programme from the Institute of Oceanology, Chinese Academy of Sciences (IOCAS). The authors deeply appreciated the help of Xiang-Tian Lin and Xue-Feng Sun, Lianyungang Health Inspection Agency, for their assistance in sample collection; and Professor Su-Ping Zhang, IOCAS, for her supervision in the identification of the nassariid samples.