Zebrafish Embryos as a Model for Cyanobacterial Toxins

描述(申请人提供)：蓝藻，或“蓝绿藻”，特别是在淡水栖息地，被认为会产生一系列潜在的有毒化合物。越来越多的证据表明，产毒蓝藻严重危害人类和环境健康。开发新的方法将是理解蓝藻毒素在环境健康中的当前和正在出现的作用的关键。这项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的有毒或其他生物活性代谢物。这项研究将从两个生态独特和截然不同的淡水微生物群落中分离和培养蓝藻，即佛罗里达沼泽地(以及南佛罗里达州的相关水道)和北部五大湖。将利用斑马鱼胚胎作为脊椎动物发育的模型来筛选蓝藻分离株，以确定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已识别毒素的初步纯化，以实现潜在新化合物的化学和生物学表征的目标。此外，斑马鱼模型将专门用于研究蓝藻中一种普遍存在的细菌毒素--脂多糖(LPS)。虽然来自革兰氏阴性异养真细菌的LPS(或“内毒素”)已经被很好地描述，但来自蓝藻的相同化合物在很大程度上还没有被探索过。然而，新出现的证据表明，蓝藻LPS可能对某些“解毒酶”有特定的影响，并随后与其他毒素相互作用。因此，这项拟议的研究将进一步利用斑马鱼胚胎模型来检验与LPS相关的几个假说，特别是来自分离的微囊藻菌株的LPS对重金属毒性和积累的影响。拟议的研究将大大有助于我们越来越多地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.