PIRE: Advancing Global Strategies and Understanding on the Origin of Ciguatera Fish Poisoning in Tropical Oceans

主要研究者：Alison Robertson（南亚拉巴马大学）联合PI：Donald安德森（伍兹霍尔海洋研究所）Deana Erdinger（德克萨斯大学奥斯汀分校）Michael Parsons（佛罗里达墨西哥湾沿岸大学）泰勒史密斯（维尔京群岛大学）非技术摘要：珊瑚礁生态系统是地球上生物多样性最丰富的栖息地之一，为沿海社区提供了至关重要的社会效益和渔业资源。对利用这些资源的一个重大威胁是雪卡毒鱼中毒，这是最普遍的非细菌性海产品疾病。CFP是由食用积累了雪卡毒素（CTX）的珊瑚鱼引起的。这些有效的神经毒素是由生活在水生植物表面的微观藻类（腰鞭毛虫）产生的（例如，大型藻类、海草），并通过食草鱼类和无脊椎动物的饮食进入珊瑚礁食物网。当这些毒素通过海洋食物网移动时，它们通过新陈代谢改变结构并增加效力。人类暴露于CTX导致疾病快速发作，持续时间为6-8周。症状包括胃肠道不适、神经功能障碍和心血管异常。目前没有有效的治疗方法或诊断测试可用于CFP，也没有可行的现场测试用于人类消费鱼类的上市前监测。尽管其严重性和流行性，CFP仍然是一个未被充分认识和报告的问题。大多数社区渔业方案影响到偏远岛屿社区的低社会经济地位群体，他们依靠当地海产品维持生计。然而，大陆地区因休闲捕鱼和国际海产品贸易而导致的鱼中毒事件正在增加，温带地区的风险也在增加。该项目的一个主要目标是更好地了解影响源生物产生CTX的环境条件，并确定毒素通过食物网在地理区域的命运。国际合作伙伴来自香港，古巴，挪威，加拿大，苏格兰（英国）和澳大利亚。技术摘要：虽然机制和环境驱动因素的遗传表型的冈比亚盘菌。虽然目前还不清楚，但许多其他的藻类生活在同一群落中，能够产生有毒的代谢物，进入食物网。这些毒素的身份和毒性在很大程度上是未知的，但他们的澄清是至关重要的监测方法的发展，保护公众健康的CFP。 CFP的管理策略远远落后于其他海产品安全问题，主要有以下四个方面的缺陷：1）无法容易地识别和监测引起CFP的产毒甘比藻物种和菌株; 2）缺乏对这些底栖微藻产生的次级代谢产物的毒性和结构的了解; 3）对这些代谢产物的食物网动力学和生物转化的了解有限;以及，4）无法预测CFP最有可能在何时何地爆发。基于这些相互关联的需求，我们已经为我们的PIRE计划开发了一个中心假设：产藻底栖甲藻产生一套稳定的次级代谢产物（元代谢组），使它们能够在由附生植物群，可用基质和环境条件变化驱动的不稳定环境中繁荣。此外，在此元代谢组中获得的稳定性和优势是普遍的，在整个产藻属，适用于许多（亚）热带礁环境。这一假设将通过检查地球仪周围珊瑚礁中的产毒冈比亚盘菌的动态和持久性来检验，以更好地了解其有毒代谢物的产生和归宿。假设检验将包括三个研究目标：1）评估珊瑚礁生态系统中附生植物和甘比尔盘菌群落的多样性和跨时空尺度和环境梯度的大型植物宿主选择性; 2）描述这些群落的元代谢物组，从结构上阐明关键代谢物，并开发评估其毒性和功能作用的方法; 3）利用生物指示物种（初级生产者和消费者）的化学生物标志物（毒素、脂类、稳定同位素），并模拟其在珊瑚礁食物网中的命运。为了实现这些研究目标，我们将与美国和国际合作伙伴一起参与一项研究计划，该计划整合了专业知识，通过在高度流行地区工作来解决CFP的全球性，并为来自美国和国外的本科生和研究生开发独特而持久的教育经验。

PI: Alison Robertson (University of Southern Alabama)co-PIs: Donald Anderson (Woods Hole Oceanographic Institution)Deana Erdner (University of Texas - Austin)Michael Parsons (Florida Gulf Coast University)Tyler Smith (University of the Virgin Islands)Nontechnical Abstract:Coral reef ecosystems are among the most biodiverse habitats on earth, providing societal benefits and fishery resources critical to coastal communities. A significant threat to utilizing these resources is ciguatera fish poisoning (CFP), the most prevalent non-bacterial seafood illness. CFP is caused by the consumption of reef fish that have accumulated ciguatoxins (CTXs). These potent neurotoxins are produced by microscopic algae (dinoflagellates) that live on the surfaces of aquatic plants (e.g., macroalgae, seagrasses) and enter reef food webs through the diet of herbivorous fish and invertebrates. As these toxins move through the marine food web they are structurally modified via metabolism and increase in potency. Human exposure to CTX results in rapid onset of illness and duration of 6-8 weeks. Symptoms include gastrointestinal distress, neurological dysfunction, and cardiovascular abnormalities. There are currently no effective treatments or diagnostic tests available for CFP, and no field tests feasible for pre-market surveillance of fish destined for human consumption. Despite its severity and prevalence, CFP remains an underappreciated and under-reported problem. Most CFP affects low socioeconomic groups in remote island communities who rely on local seafood for subsistence. However, fish poisonings from recreational fishing and the international seafood trade are increasing in continental areas increasing exposure in temperate regions. A major goal of this PIRE project will be to better understand the environmental conditions affecting the production of CTXs by the source organisms and to determine the fate of the toxins through the food web across geographical regions. International partners are from Hong Kong, Cuba, Norway, Canada, Scotland (UK) and Australia.Technical Abstract:While the mechanisms and environmental drivers of toxigenic phenotypes of Gambierdiscus spp. remain unknown, many other toxigenic algae live in the same community and are capable of producing toxic metabolites that can enter the food web. The identity and toxicity of these toxins are largely unknown, but their elucidation is critical to the development of monitoring approaches for public health protection of CFP. Management strategies for CFP lag far behind other seafood safety issues due to four major deficiencies: 1) the inability to easily identify and monitor for the toxigenic Gambierdiscus species and strains responsible for CFP; 2) a lack of knowledge on the toxicity and structure secondary metabolites produced by these benthic micro-algae; 3) a limited understanding of the food web dynamics and biotransformations of these metabolites; and, 4) the inability to predict when and where CFP outbreaks are most likely to occur. Based on these interlinked needs, we have developed a central hypothesis for our PIRE program: toxigenic benthic dinoflagellates produce a stable suite of secondary metabolites (meta-metabolome) allowing them to prosper in an otherwise unstable environment driven by shifts in the epiphytic flora, available substrates, and environmental conditions. Moreover, the stability and advantages gained in this meta-metabolome are universal across toxigenic genera and applicable to many (sub)tropical reef environments. This hypothesis will be tested by examining the dynamics and persistence of toxigenic Gambierdiscus in reefs around the globe to better understand the production and fate of their toxic metabolites. Hypothesis testing will comprise three research objectives: 1) Evaluate epiphyte and Gambierdiscus community diversity and macrophyte host selectivity across spatio-temporal scales and environmental gradients in coral reef ecosystems; 2) Characterize the meta-metabolome of these communities, structurally elucidate key metabolites, and develop methods to evaluate their toxicity and functional role; 3) Utilize chemical biomarkers (toxins, lipids, stable isotopes) in bio-indicator species (primary producers and consumers) and model their fate in reef food webs. To achieve these research goals we will engage in a research program with US and International partners that integrates expertise, addresses the global nature of CFP by working across hyper-endemic regions, and develops unique and lasting educational experiences for undergraduate and graduate students from the US and abroad.