Zebrafish Embryos as a Model for Cyanobacterial Toxins

描述（由申请人提供）：蓝藻，或“蓝绿藻”，特别是在淡水栖息地，被认为可以产生一系列强毒性化合物。越来越多的证据表明，产毒蓝藻对人类和环境健康构成严重关切。新方法的发展将是关键，以了解当前和新兴的角色蓝藻毒素在环境健康。拟议的研究将利用斑马鱼（Danio rerio）胚胎作为毒理学模型来研究蓝藻细菌的毒性或其他生物活性代谢物。这项研究将从两个生态独特的淡水微生物群落中分离和培养蓝藻，即佛罗里达大沼泽地（以及南佛罗里达的相关水道）和北部五大湖。蓝藻分离物将使用斑马鱼胚胎作为脊椎动物发育模型进行筛选，专门用于识别干扰发育途径的代谢物（即发育毒素）。生物测定将进一步用于指导鉴定毒素的初始纯化，以实现潜在新化合物的化学和生物学特性。此外，斑马鱼模型将被专门用于研究一种普遍存在的细菌毒素，即来自蓝藻的脂多糖（lps）。虽然来自革兰氏阴性异养真细菌的lps（或“内毒素”）被很好地描述，但来自蓝藻细菌的相同化合物在很大程度上尚未被探索。然而，新出现的证据表明，蓝藻脂多糖可能对某些“解毒酶”有特定的影响，并随后与其他毒素产生相互作用。因此，本研究将进一步利用斑马鱼胚胎模型来验证与脂多糖（特别是来自微囊藻分离菌株的脂多糖）对重金属毒性和积累的影响有关的几个假设。拟议的研究将大大有助于我们日益了解淡水蓝藻毒素在环境健康中的作用。

DESCRIPTION (provided by applicant): Cyanobacteria, or "blue-green algae," particularly in freshwater habitats, are recognized to produce an array of potently toxic compounds. Growing evidence indicates that toxigenic cyanobacteria represent a serious concern to human and environmental health. Development of novel approaches will be key to understanding both current and emerging roles of cyanobacterial toxins in environmental health. The proposed research will utilize the zebrafish (Danio rerio) embryo as a toxicological model to investigate toxic or otherwise bioactive metabolites from cyanobacteria. This research will isolate and culture cyanobacteria from two, ecologically unique and distinct freshwater microbial communities, namely the Florida Everglades (and associated waterways in South Florida) and the northern Great Lakes. Cyanobacterial isolates will be screened using the zebrafish embryo as a model of vertebrate development specifically to identify metabolites which interfere with developmental pathways (i.e. developmental toxins). The bioassay will be further utilized to guide initial purification of identified toxins toward the goal of chemical and biological characterization of potentially novel compounds. In addition, the zebrafish model will be used specifically to investigate a ubiquitous class of bacterial toxins, the lipopolysaccharides (LPSs), from cyanobacteria. Though LPSs (or "endotoxins") from Gram-negative heterotophic eubacteria are well described, the same compounds from cyanobacteria have been largely unexplored. However, emerging evidence indicates that cyanobacterial LPSs may have specific effects on certain "detoxifying enzymes," and a subsequent interactive effects with other toxins. Accordingly, the proposed research will further utilize the zebrafish embryo model to test several hypothesis related to the effects of LPSs, specifically from isolated strains of Microcystis, on heavy metal toxicity and accumulation. The proposed research will contribute significantly to our growing understanding of the role of freshwater cyanobacterial toxins in environmental health.