Regulation of Toxicity in the Dinoflagellate Alexandrium

9415536安德森 项目摘要 亚历山大藻属的有毒甲藻大量繁殖导致麻痹性贝类中毒（PSP）的爆发，这是全球海洋现象中较为严重的一种，统称为“赤潮”。 PSP爆发对经济、公共卫生和生态系统的影响有多种形式，包括人类中毒和受污染的贝类或鱼类死亡，渔业物种的阶段，以及海洋哺乳动物、鱼类和海鸟的死亡。 这些影响是由石房蛤毒素引起的，石房蛤毒素是甲藻产生的一种神经毒素，在浮游动物、贝类或鱼类进食时积累。 该项目的总体目标是确定Alexandrum spp中参与毒素产生的基因。和其他产生石房蛤毒素的生物，并研究它们的调节方式。 该方法将使用差异显示来识别细胞之间的信使RNA差异，这些细胞在制造毒素的能力上不同。 然后，差异表达的序列可以用于筛选在广泛的有毒和无毒的甲藻和蓝藻物种中的推定毒素基因。 其他间接证据的毒素特异性的基因将来自甲藻代谢的操作，使用抑制剂，阻止毒素的生物合成在不同的水平。 如果差异显示方法是不成功的，因为毒素基因在转录水平上不受调节，传统的方法的二维蛋白电泳将应用于亚历山大草提取物从不同的细胞周期阶段，以解决翻译/翻译后调节的剩余可能性。 这反过来将导致识别和分离与毒素产生有关的基因。 上述两种方法都将提供进行调控研究所需的遗传工具，以确定这些基因开启和关闭的机制。 所获得的信息将有助于破译一些长期存在的谜团周围的石房蛤毒素在甲藻的代谢作用和毒素的变异性观察到不同的菌株或在不同的环境条件下的个别菌株。

9415536 Anderson PROJECT ABSTRACT Blooms of toxic dinoflagellates in the genus Alexandrium result in outbreaks of paralytic shellfish poisoning (PSP), one of the more serious of the global marine phenomena collectively termed "red tides". The economic, public health, and ecosystem impacts of PSP outbreaks take a variety of forms, and include human intoxications and death from contaminated shellfish or fish, stages of fisheries species, and death of marine mammals, fish, and seabirds. These impacts are caused by the saxitoxins, a family of neurotoxins produced by the dinoflagellates and accumulated in zooplankton, shellfish, or fish during feeding. The overall objective of this project is to identify genes involved in toxin production in Alexandrium spp. and other saxitoxin-producing organisms and to study the manner in which they are regulated. The approach will use differential display to identify messenger RNA differences between cells that differ in their ability to make toxin. Differentially expressed sequences can then be used to screen for the putative toxin genes in a wide range of toxic and non-toxic species of dinoflagellates and cyanobacteria. Other indirect evidence for the toxin-specificity of the identified genes will derive from manipulations of dinoflagellate metabolism using inhibitors that block toxin biosynthesis at different levels. If the differential display approach is not successful because the toxin genes are not regulated at the transcriptional level, traditional methods of two-dimensional protein electrophoresis will be applied to extracts of Alexandrium from different cell cycle stages to address the remaining possibility of translational/post-translational regulation. This in turn will lead to the identification and isolation of genes implicated in toxin production. Both of the above approaches will provide genetic tools needed to conduct regulatory studies to determine the mechanisms by which these genes are turned on and off. The information gained will aid in deciphering some of the long-standing mysteries surrounding the metabolic role of saxitoxin in dinoflagellates and the toxin variability observed in different isolates or in individual isolates under different environmental conditions.