Nutritional, environmental, and genetic regulation of toxicity and growth in Dinophysis

从生态、进化和公共卫生的角度来看，甲藻属具有重要意义。在前一类中，该属的一些成员通过需要隐芽和纤毛虫捕食的独特的、多阶段的过程来获取营养。在进化上，隐芽植物叶绿体在取食过程中的修饰及其随后的光合作用利用为研究叶绿体的获取和进化提供了一个模式系统。从公共卫生的角度来看，绝大多数腹泻性贝类中毒(DSP)病例都是由假藻引起的。DSP是一种主要与食用积累了牙藻毒素的贝类有关的综合症。它是许多国家的主要健康和经济问题，也是最重要和最普遍的有害藻华(HAB)相关中毒综合征之一。几十年来，由于我们无法在实验室培养和维护这些微生物，Dinophysis的许多生理、毒性和遗传学方面仍然难以解决。然而，由于最近的一项突破，这个障碍不再存在，一系列重要的实验和测量现在是可能的。在多条战线上取得重大进展的机会很大。研究人员将进行一项全面的研究，以调查营养、环境和遗传对牙藻毒性和生长的调控。他们的总体假设是，牙藻中毒素的可变性不仅受牙藻物种和菌株之间的遗传差异的影响，还受纤毛虫和隐藻食物可获得性和质量的差异以及环境影响的影响。他们将建立一个地理上多样化的培养集合，并对其进行遗传学特征描述，其中将包括Dinophysis、Myrionecta和其他纤毛虫的各种分离株，以及隐芽植物。在提交之前，这些文化收藏的大部分已经组装好了。然后，培养组合将被用来研究齿藻和纤毛虫的取食选择性、放牧率和生长。下一个主要目标是探索藻类毒素变异的潜在机制。这将包括对地理上分散的以纤毛虫和隐芽植物为食的牙藻分离株的分析，以及对环境因素(如温度、光照和营养物质)在毒素产生中的作用的检查。该研究项目将依赖于一种经过验证的系统和方法--在PI的实验室中以高速度生长了数月的Dinophysis的培养，建立了实验方案，以及使用最先进的仪器和技术的复杂的毒素化学。该项目将开始回答甲藻生理学、生态学、毒性和进化方面的长期问题，同时提供关于重大公共健康和经济问题的有价值的信息。该项目适用于本科生、研究生和博士后培训。皮安德森将在这个项目上为一名博士生提供支持，并将让几名本科生实习生参与这项研究。安德森通常为东北大学的几名实习生提供支持，他们在实验室工作6个月，以获得指导教育和职业选择的经验。博士后学者朱丽叶·史密斯将以世界卫生组织奖学金的身份参与毒素分析。由此产生的培养物收藏将与该领域的其他工作人员共享，以加速科学进步。项目成果将通过科学论文、在讲习班、会议和研讨会上的陈述以及与媒体的讨论来广泛传播。此外，由于正在研究的生物是影响世界各国的一种主要形式的贝类中毒的罪魁祸首，该项目具有重大的实际意义，很容易满足促进发现与其为社会服务之间的联系的标准。

The dinoflagellate genus Dinophysis is important from ecological, evolutionary, and public health perspectives. In the former category, some members of this genus derive their nutrition through a unique, multi-stage process requiring cryptophyte and ciliate prey. Evolutionarily, the modification of cryptophyte chloroplasts during feeding and their subsequent utilization for photosynthesis provides a model system for investigations of plastid acquisition and evolution. From the public health perspective, Dinophysis species are responsible for the vast majority of diarrhetic shellfish poisoning (DSP) cases. DSP is a syndrome predominantly associated with consumption of shellfish that have accumulated Dinophysis toxins. It is a major health and economic problem for many countries and is among the most important and widespread of the harmful algal bloom (HAB)-associated poisoning syndromes.For decades, many aspects of Dinophysis physiology, toxicity, and genetics have remained intractable due to our inability to grow and maintain these organisms in laboratory cultures. As a result of a recent breakthrough, however, this obstacle no longer exists and an array of important experiments and measurements are now possible. The opportunities for major advances on multiple fronts are significant. The investigators will conduct a comprehensive study to investigate nutritional, environmental, and genetic regulation of toxicity and growth in Dinophysis. Their overall hypothesis is that toxin variability in Dinophysis is regulated not only by genetic differences among Dinophysis species and strains, but also by differences in ciliate and cryptophyte food availability and quality, and by environmental influences as well. They will establish and genetically characterize a geographically diverse culture collection that will include a variety of isolates of Dinophysis, Myrionecta and other ciliates, and cryptophytes. Much of this culture collection has already been assembled in advance of this submission. The culture assemblage will then be used to investigate Dinophysis and ciliate feeding selectivity, grazing rates, and growth. The next major objective is to explore mechanisms underlying toxin variability in Dinophysis. This will include analysis of geographically dispersed Dinophysis isolates fed with an array of ciliates and cryptophytes, as well as an examination of the role of environmental factors such as temperature, light, and nutrients in toxin production. The research project will rely on a proven system and methods - cultures of Dinophysis that have been growing at high rates in the PI's laboratory many months, established experimental protocols, and sophisticated toxin chemistry using state-of-the-art instruments and techniques. This project will begin to answer longstanding questions in dinoflagellate physiology, ecology, toxicity, and evolution while providing valuable information on a significant public health and economic problem.Broader Impacts. This project lends itself to undergraduate, graduate, and postdoctoral training. PI Anderson will support a PhD student on this project and will involve several undergraduate interns in the study as well. Anderson typically supports several Northeastern University interns who work in the laboratory for 6 months to obtain experience to guide education and career options. Postdoctoral Scholar Juliette Smith will participate in the toxin analysis, on a WHOI fellowship. The resulting culture collection will be shared with others working in this field to accelerate scientific progress. Project results will be broadly disseminated through scientific papers, presentations at workshops, conferences, and seminars, and discussions with the media. Furthermore, since the organisms being studied are responsible for a major form of shellfish poisoning that affects countries throughout the world, this project has significant practical implications that readily satisfy the criterion fostering connections between discoveries and their use in the service of society.