IRCEB: Host-Pathogen Biology and the Global Decline of Amphibians

IRCEB：宿主病原体生物学和两栖动物的全球衰退

• 批准号: 9977063
• 负责人: James Collins
• 金额: $ 297.58万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-15 至 2003-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9977063&HistoricalAwards=false
• 关键词: IRCEB; Host; Pathogen; Biology; Global

9977063Collins et al. We propose an IRCEB in host-pathogen biology with a strong problem-solving focus designed to enhance collaboration and encourage pursuit of answers beyond the boundaries of traditional scientific disciplines. Host-pathogen interactions alternately fascinate and frustrate biologists. The fascination stems from the opportunities these systems offer as models for understanding at a basic level the complex mechanisms underlying organismal relationships. The frustration stems from not understanding these interactions sufficiently well to anticipate or react to epidemics or epizootics. Ecologists increasingly acknowledge a role for pathogens in population dynamics and in maintaining diverse communities and ecosystems. We have a poor understanding, however, of how pathogens alter host population dynamics, how pathogens infect hosts in a population, and how host and pathogen populations coevolve. In many populations, hosts and pathogens coexist and each shows regular increases and decreases in population size. At times, however, a pathogen nearly or completely decimates its host population. We propose testing the basic mechanisms underlying each of these patterns using amphibians as a model system. Most amphibian populations regularly fluctuate in numbers of individuals, but beginning about 1989 herpetologists became alarmed by reports that populations and even species were persistently declining, some to extinction. Extreme population fluctuations and declines are centered on a broad region of the Cordilleras of western North America from southern Saskatchewan south to Costa Rica and northern Panama, and the higher elevations of Australia from southeastern to north Queensland. Four main causes seem to be acting alone, sequentially, or synergistically: habitat destruction, exotic species, disease, and anthropogeneic environmental change due to toxic chemicals, UB radiation, or global climate change. Many regions with declines are conservation areas protected from exotic species and habitat destruction suggesting subtle, complex causes like environmental change or pathogens are at work. We have assembled an international research team to answer the question: Why are pathogens causing some amphibian populations to decline, even to extinction? The evidence suggests a pathogenic chytrid fungus causes populations to plummet, while another pathogen, an iridovirus causes amphibian populations to fluctuate. The proposed research will address the questions: How do pathogens influence host population dynamics? Are these newly-introduced amphibian pathogens, or has the virulence of historically benign amphibian associates changed? Have recent environmental changes altered amphibian-pathogen interactions? Except for some cases involving humans as hosts (e.g., cholera, malaria), few host-pathogen interactions have been dissected from molecular biology to population dynamics. Our team will do just that to advance basic host-pathogen biology with the goal of applying our findings to one of the most significant global biodiversity problems facing us today: Why are amphibian populations declining? Metaphorically, the declining amphibian problem is like a prism in reverse: instead of dispersing colors, it focuses research disciplines - ecology, evolution, organismal biology, genetics, pathology, and immunology - so that they no longer appear individually. Understanding the basic mechanisms of host-pathogen interactions is central to our proposal and essential for answering the question of why amphibians are declining. The point of this metaphor is that while a spectrum can be "divided" into its colors, the variation is continuous - "divisions" are artificial and at the origin they disappear. Amphibians are integral parts of ecosystems in ways that place them at this metaphorical core. Therefore, we need a diversity of disciplines and a diversity of investigators willing to collaborate on integrative research projects. The declining amphibian case in an exciting, but unfortunate, opportunity to explore the boundaries of host-pathogen biology, and the time is now to understand why amphibians are declining. The point of our IRCEB research program is to meld diverse disciplinary concepts, methods, and traditions in ways that advance our understanding of pathogens as a factor in amphibian declines, a key example of the general loss of biodiversity.

9977063柯林斯等人。我们提出了宿主-病原体生物学领域的 IRCEB，其重点是解决问题，旨在加强合作并鼓励超越传统科学学科的界限寻求答案。 宿主与病原体的相互作用时而令生物学家着迷，时而令其沮丧。 这些系统的魅力源于这些系统提供的机会，作为从基本层面理解有机体关系背后的复杂机制的模型。 挫败感源于对这些相互作用的理解不够充分，无法预测或应对流行病或动物流行病。 生态学家越来越认识到病原体在种群动态以及维持多样化群落和生态系统中的作用。 然而，我们对病原体如何改变宿主种群动态、病原体如何感染种群中的宿主以及宿主和病原体种群如何共同进化知之甚少。在许多种群中，宿主和病原体共存，并且各自的种群规模都有规律的增加和减少。 然而，有时病原体几乎或完全消灭其宿主种群。 我们建议使用两栖动物作为模型系统来测试这些模式背后的基本机制。 大多数两栖动物种群的个体数量经常波动，但大约从 1989 年开始，爬行动物学家对种群数量甚至物种持续减少、有些甚至灭绝的报道感到震惊。 人口极端波动和下降集中在北美西部科迪勒拉山脉的广大地区，从萨斯喀彻温省南部到哥斯达黎加和巴拿马北部，以及澳大利亚从东南部到昆士兰州北部的较高海拔地区。 四个主要原因似乎单独、连续或协同作用：栖息地破坏、外来物种、疾病以及有毒化学品、紫外线辐射或全球气候变化造成的人为环境变化。 许多下降的地区都是保护区，免受外来物种和栖息地破坏的影响，这表明环境变化或病原体等微妙而复杂的原因正在发挥作用。我们组建了一个国际研究小组来回答这个问题：为什么病原体会导致一些两栖动物种群减少，甚至灭绝？ 有证据表明，致病性壶菌会导致种群数量骤减，而另一种病原体虹彩病毒则会导致两栖动物种群数量波动。 拟议的研究将解决以下问题：病原体如何影响宿主种群动态？ 这些是新引入的两栖动物病原体，还是历史上良性两栖动物伙伴的毒力发生了变化？ 最近的环境变化是否改变了两栖动物与病原体的相互作用？ 除了一些涉及人类作为宿主的病例（例如霍乱、疟疾）外，很少有宿主与病原体的相互作用从分子生物学到种群动态进行了剖析。 我们的团队将这样做，以推进基本的宿主病原体生物学，目标是将我们的发现应用于当今我们面临的最重要的全球生物多样性问题之一：为什么两栖动物种群数量下降？打个比方，日益减少的两栖动物问题就像一个倒转的棱镜：它不再分散颜色，而是集中研究学科——生态学、进化论、有机生物学、遗传学、病理学和免疫学——使它们不再单独出现。 了解宿主与病原体相互作用的基本机制是我们建议的核心，对于回答两栖动物为何数量减少的问题至关重要。 这个比喻的要点是，虽然光谱可以“划分”为其颜色，但变化是连续的——“划分”是人为的，并且在起源处它们消失了。 两栖动物是生态系统不可或缺的一部分，这将它们置于这个隐喻的核心。 因此，我们需要愿意在综合研究项目上进行合作的多元化学科和多元化研究人员。 两栖动物数量减少的案例是一个令人兴奋但不幸的探索宿主-病原体生物学界限的机会，现在是时候了解两栖动物数量减少的原因了。 我们 IRCEB 研究计划的重点是融合不同的学科概念、方法和传统，以增进我们对病原体作为两栖动物数量减少的一个因素的理解，这是生物多样性普遍丧失的一个重要例子。