Pierce R H, Henry M S
Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236, USA.
Ecotoxicology. 2008 Oct;17(7):623-31. doi: 10.1007/s10646-008-0241-x. Epub 2008 Aug 30.
The Florida red tide is a descriptive name for high concentrations of the harmful marine alga, Karenia brevis. Although most prevalent along the south-west Florida coast, periodic blooms have occurred throughout the entire US and Mexico Gulf coasts and the Atlantic coast to North Carolina. This dinoflagellate produces a suite of polyether neurotoxins, called brevetoxins, that cause severe impacts to natural resources, as well as public health. These naturally produced biotoxins may represent one of the most common chemical stressors impacting South Florida coastal and marine ecosystems. Impacts include massive fish kills, marine mammal, sea turtle and sea bird mortalities, benthic community die-off and public health effects from shellfish contamination and inhalation of air-borne toxins. The primary mode of action is binding to voltage-gated sodium channels causing depolarization of nerve cells, thus interfering with nerve transmission. Other effects include immune depression, bronchial constriction and haemolysis. Parent algal toxins are synthesized within the unicellular organism, others are produced as metabolic products. Recent studies into the composition of brevetoxins in cells, water, air and organisms have shown PbTx-2 to be the primary intracellular brevetoxin that is converted over time to PbTx-3 when the cells are ruptured, releasing extracellular brevetoxins into the environment. Brevetoxins become aerosolized by bubble-mediated transport of extracellular toxins, the composition of which varies depending on the composition in the source water. Bivalved molluscs rapidly accumulate brevetoxins as they filter feed on K. brevis cells. However, the parent algal toxins are rapidly metabolized to other compounds, some of which are responsible for neurotoxic shellfish poisoning (NSP). These results provide new insight into the distribution, persistence and impacts of red tide toxins to south-west Florida ecosystems.
佛罗里达赤潮是对有害海洋藻类——短裸甲藻大量繁殖现象的一种描述性称谓。尽管在佛罗里达州西南海岸最为常见，但周期性的藻华现象已在美国和墨西哥湾沿岸以及北卡罗来纳州的大西洋沿岸出现。这种甲藻会产生一系列称为短裸甲藻毒素的聚醚神经毒素，对自然资源以及公众健康造成严重影响。这些天然产生的生物毒素可能是影响佛罗里达州南部沿海和海洋生态系统的最常见化学应激源之一。其影响包括大量鱼类死亡、海洋哺乳动物、海龟和海鸟死亡、底栖生物群落灭绝以及贝类污染和吸入空气中毒素对公众健康的影响。主要作用方式是与电压门控钠通道结合，导致神经细胞去极化，从而干扰神经传递。其他影响包括免疫抑制、支气管收缩和溶血。母体藻类毒素在单细胞生物体内合成，其他毒素则作为代谢产物产生。最近对细胞、水、空气和生物体中短裸甲藻毒素成分的研究表明，PbTx - 2是主要的细胞内短裸甲藻毒素，当细胞破裂时，随着时间的推移会转化为PbTx - 3，将细胞外短裸甲藻毒素释放到环境中。短裸甲藻毒素通过气泡介导的细胞外毒素运输形成气溶胶，其成分因源水中的成分而异。双壳贝类在滤食短裸甲藻细胞时会迅速积累短裸甲藻毒素。然而，母体藻类毒素会迅速代谢为其他化合物，其中一些是导致神经性贝类中毒（NSP）的原因。这些结果为赤潮毒素在佛罗里达州西南部生态系统中的分布、持久性和影响提供了新的见解。
