Anderson D M, Kulis D M, Qi Y Z, Zheng L, Lu S, Lin Y T
Biology Department, Woods Hole Oceanographic Institution, MA 02543-1049, USA.
Toxicon. 1996 May;34(5):579-90. doi: 10.1016/0041-0101(95)00158-1.
The rapidly expanding mariculture and commercial region along the southern coast of China has experienced sporadic outbreaks of paralytic shellfish poisoning for nearly 30 years, yet virtually nothing is known of the nature of that toxicity or of the causative organisms. This study presents the first direct comparisons of the high performance liquid chromatography toxin composition profiles of shellfish implicated in paralytic shellfish poisoning outbreaks in Daya Bay with Alexandrium tamarense cultures established from those waters. The three cultures that were analyzed produced an unusually high proportion of the low potency N-sulfocarbamoyl toxins C1 and C2 (nearly 90% of the total), and only trace quantities of the other saxitoxin derivatives. Total toxicity was thus very low with mild acid extraction, ranging between 7.2 and 12.7 fmole cell-1, or 0.7-0.9 pg saxitoxin equiv. cell-1. Following acid hydrolysis using the standard AOAC extraction method, the dominant toxins in the cultures were gonyautoxins 2 and 3 and decarbamoyl gonyautoxins 2 and 3. Total potency increased fourfold to 2.6-3.4 pg saxitoxin equiv. cell-1 following acid hydrolysis. These cultures are thus at the low end of the range of toxicities recorded for members of the A. tamarense species complex. Two scallop samples and one mussel sample collected from Daya Bay during paralytic shellfish poisoning episodes in 1990 and 1991 were also analyzed following the AOAC extraction procedure. The toxin profiles were similar for the three shellfish samples, in that the same suite of toxins were present in each, but the relative proportion of those toxins varied. The dominant toxins were gonyautoxins 2 and 3 and toxins C1-C4. Total toxicity was 336 and 654 micrograms saxitoxin per 100 g meat for the scallop samples, and 723 for the mussels. Toxins C3,4 were present in the shellfish at up to 22 mole%, but were not detected in cultures, even when mild acid was used for extraction. Despite the otherwise similar nature of the culture versus the shellfish toxin signatures, the presence of C3,4 indicates that another strain or species of Alexandrium, or possibly a paralytic shellfish poisoning-producing species of another genus was responsible for the 1990 and 1991 paralytic shellfish poisoning outbreaks in Daya Bay. Since the cultures analyzed were of low intrinsic toxicity, A. tamarense may be more widespread along the south coast of China than is suggested by the sporadic pattern of past paralytic shellfish poisoning outbreaks. Blooms with high cell density are required to generate sufficient toxin to be dangerous. The alarming increase in algal blooms in Chinese waters due to persistent and growing pollution may make these low toxicity populations more problematic in the future.
在中国南部沿海迅速扩张的海水养殖和商业区域，近30年来曾零星爆发过麻痹性贝类中毒事件，但对于这种毒性的本质或致病生物几乎一无所知。本研究首次直接比较了大亚湾麻痹性贝类中毒事件中涉事贝类的高效液相色谱毒素成分谱与从这些水域分离出的塔玛亚历山大藻培养物的毒素成分谱。所分析的三种培养物产生的低毒N-磺基甲酰基毒素C1和C2比例异常高（几乎占总量的90%），而其他石房蛤毒素衍生物仅为痕量。因此，采用温和酸提取法时总毒性非常低，范围在7.2至12.7飞摩尔/细胞-1之间，即0.7 - 0.9皮克石房蛤毒素当量/细胞-1。使用标准AOAC提取法进行酸水解后，培养物中的主要毒素为膝沟藻毒素2和3以及脱氨甲酰基膝沟藻毒素2和3。酸水解后总毒性增加了四倍，达到2.6 - 3.4皮克石房蛤毒素当量/细胞-1。因此，这些培养物的毒性处于塔玛亚历山大藻物种复合体成员记录毒性范围的低端。1990年和1991年麻痹性贝类中毒事件期间从大亚湾采集的两个扇贝样本和一个贻贝样本，也按照AOAC提取程序进行了分析。这三个贝类样本的毒素谱相似，即每种样本中都存在相同的一组毒素，但这些毒素的相对比例有所不同。主要毒素为膝沟藻毒素2和3以及毒素C1 - C4。扇贝样本每100克肉的总毒性为336和654微克石房蛤毒素，贻贝样本为723微克。毒素C3、4在贝类中的含量高达22摩尔%，但在培养物中未检测到，即使使用温和酸进行提取也未检测到。尽管培养物与贝类毒素特征在其他方面相似，但C3、4的存在表明，另一种亚历山大藻菌株或物种，或者可能是另一个属的产生麻痹性贝类中毒的物种，是1990年和1991年大亚湾麻痹性贝类中毒事件的起因。由于所分析的培养物内在毒性较低，塔玛亚历山大藻在中国南部沿海可能比过去麻痹性贝类中毒事件的零星模式所显示的更为广泛。需要高细胞密度的藻华才能产生足够危险的毒素。由于持续且日益严重的污染，中国海域藻华惊人地增加，这可能使这些低毒性种群在未来引发更多问题。
