Woofter Ricky T, Brendtro Kirsten, Ramsdell John S
Marine Biotoxins Program, Center for Coastal Environmental Health and Biomolecular Research, National Oceanic and Atmospheric Administration-National Ocean Service, Charleston, South Carolina 29412, USA.
Environ Health Perspect. 2005 Jan;113(1):11-6. doi: 10.1289/ehp.7274.
There is a critical need to simply and reliably monitor brevetoxins routinely in the blood of humans and aquatic animals. We used striped mullet as laboratory test animals to better define the uptake and elimination kinetics of brevetoxin during an aqueous exposure to the brevetoxin-producing dinoflagellate Karenia brevis. Striped mullet were first exposed to sublethal densities of K. brevis (approximately 250,000 cells/L) for 1, 4, 8, 12, and 24 hr. No mortality was observed in the aquaria, and at each time point blood samples were taken and applied to blood collection cards for brevetoxin analysis using radioimmunoassay (RIA). The RIA indicated that blood levels of brevetoxin (PbTx-3) increased to values significantly different from that of the controls at all five time points during exposure (p < 0.05). Striped mullet were then exposed to a K. brevis culture with a known brevetoxin concentration of 0.5 ng/mL. Even after exposures at a low brevetoxin concentration, RIA was able to detect 2.25 +/- 0.62 ng/mL PbTx-3 equivalents in the blood of the mullet at 8 hr of exposure. When exposed to higher brevetoxin concentrations (3.5 and 5.4 ng/mL), blood brevetoxin increased to peak levels at 12 hr and then reached equilibrium after 24 hr in the continued presence of K. brevis. During this time of equilibrium, the mullet maintained brevetoxins with a blood:water coefficient of 2.2. To define the elimination of brevetoxin, striped mullet were next exposed for 8-10 hr and then transferred to fresh seawater containing no K. brevis for up to 116 hr. Blood brevetoxin levels remained elevated and decreased only by 50% 116 hr after transfer. The rate of elimination fit best to a two-phase exponential decay with a biologic half-life of 12 and 266 hr. This study, using RIA in conjunction with blood collection cards, demonstrates an effective means to monitor blood brevetoxin levels in finfish and provides a foundation to characterize biologically relevant levels of brevetoxin in other species impacted by red tide events.
迫切需要一种简单可靠的方法来常规监测人类和水生动物血液中的短裸甲藻毒素。我们使用条纹鲻鱼作为实验动物，以更好地确定在水体暴露于产短裸甲藻毒素的甲藻——短裸甲藻期间，短裸甲藻毒素的摄取和消除动力学。条纹鲻鱼首先暴露于亚致死密度的短裸甲藻（约250,000个细胞/升）中1、4、8、12和24小时。水族箱中未观察到死亡情况，在每个时间点采集血液样本，并将其应用于采血卡，使用放射免疫分析（RIA）进行短裸甲藻毒素分析。RIA表明，在暴露期间的所有五个时间点，短裸甲藻毒素（PbTx - 3）的血液水平均升高至与对照组显著不同的值（p < 0.05）。然后，条纹鲻鱼暴露于已知短裸甲藻毒素浓度为0.5 ng/mL的短裸甲藻培养物中。即使在低短裸甲藻毒素浓度下暴露后，RIA仍能在暴露8小时时检测到鲻鱼血液中2.25±0.62 ng/mL的PbTx - 3当量。当暴露于更高的短裸甲藻毒素浓度（3.5和5.4 ng/mL）时，血液中的短裸甲藻毒素在12小时时升至峰值水平，然后在持续存在短裸甲藻的情况下24小时后达到平衡。在这个平衡期内，鲻鱼体内短裸甲藻毒素的血 - 水系数为2.2。为了确定短裸甲藻毒素的消除情况，接下来将条纹鲻鱼暴露8 - 10小时，然后转移到不含短裸甲藻的新鲜海水中长达116小时。血液中的短裸甲藻毒素水平仍然升高，在转移116小时后仅下降了50%。消除速率最符合两相指数衰减，生物半衰期分别为12小时和266小时。这项使用RIA结合采血卡的研究，展示了一种监测硬骨鱼血液中短裸甲藻毒素水平的有效方法，并为确定受赤潮事件影响的其他物种中与生物学相关的短裸甲藻毒素水平奠定了基础。
