Amphibian Mucosal Defenses against an Emerging Fungal Disease: Testing for Selection in Recovering Populations

两栖动物粘膜防御新出现的真菌疾病：测试恢复种群的选择

• 批准号: 290658919
• 负责人: Dr. Andreas Hertz
• 金额: --
• 依托单位: Biology Department
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/290658919?language=en
• 关键词: Amphibian; Mucosal; Defenses; against; Emerging

Nowadays, amphibians are considered the most threatened vertebrate class worldwide. Besides habitat loss, Emerging Infectious Diseases (EIDs) are among the main causes for a worldwide decline in amphibian populations. The most disastrous amphibian EID is chytridiomycosis, caused by the Chytrid fungus Batrachochytrium dendrobatidis (Bd). The waterborne zoospore penetrates the amphibian skin and develops inside epidermal cells to sporangia that release new zoospores. It has been shown that the fungus is susceptible to heat, cold, and drought. Thus, it is especially epidemic in tropical highland situations with a constant cool and humid climate, where it has caused mass declines of whole amphibian communities. In Panama, chytridiomycosis related declines were first observed in the early 1990. Since then, the epidemic is spreading in a wave-like pattern from west to east along the Panamanian central mountain range. It has been proposed that stream associated highland species might have been extinct after disease outbreak. However, single populations that had suffered from chytrid related, well-documented declines have been rediscovered during recent field work, some of which even show an increase in numbers of individuals. However, the reasons why some species and populations recover are still poorly understood. Preliminary studies have shown that the effectiveness against Bd of the combined amphibian immune defense, consisting of specific antimicrobiotic peptides (AMPs), antibodies, and microbiotic secondary metabolites, may vary among species and populations. Generally, mountainous species with an aquatic tadpole stage are more likely to decline during Bd epidemics, irrespective of their taxonomic affiliation. On the contrary, population recovery following disease related population declines has been only observed in particular taxa.The main goals of this research project are to test if natural selection has led to a higher resistance of persisting amphibian populations against Bd and if phenotypic plasticity influences mucosome function of the amphibian mucosa against Bd respectively. Therefore, the mucosome function against Bd will be tested in several populations with different exposure time to the pathogen and at different altitudes. Further, it will be tested if the frog receives its probiotic skin microbiom already in the tadpole stage. In addition, it will be tested if environmental parameters like temperature and illumination have an effect on mucosome function of captive bred amphibians in ex-situ breeding programs.

目前，两栖动物被认为是世界上最受威胁的脊椎动物。除了栖息地丧失，新发传染病（EID）是全球两栖动物种群减少的主要原因之一。最具灾难性的两栖动物EID是壶菌病，由壶菌真菌Batrachochytrium dendrobaerum（Bd）引起。水媒游动孢子穿透两栖动物的皮肤，在表皮细胞内发育成孢子囊，释放出新的游动孢子。它已被证明，真菌是敏感的热，冷，和干旱。因此，它在气候持续凉爽和潮湿的热带高原地区尤其流行，导致整个两栖动物群落的大规模下降。在巴拿马，1990年初首次观察到与壶菌病有关的下降。此后，疫情沿着巴拿马中部山脉沿着由西向东呈波浪式蔓延。有人提出，与溪流有关的高地物种可能在疾病爆发后灭绝。然而，在最近的野外工作中，重新发现了与壶菌有关的、有据可查的数量下降的单一种群，其中一些种群甚至显示出个体数量的增加。然而，一些物种和种群恢复的原因仍然知之甚少。初步研究表明，由特异性抗菌肽（AMP）、抗体和微生物次级代谢产物组成的两栖动物联合免疫防御对Bd的有效性可能因物种和种群而异。一般来说，山区物种与水生蝌蚪阶段更有可能下降，在Bd流行病，无论其分类隶属关系。与此相反，人口恢复疾病相关的人口下降已被观察到，只有在特定taxi.The主要目标的研究项目是测试，如果自然选择已经导致了更高的抵抗力的持续两栖动物种群对Bd和如果表型可塑性影响的两栖动物粘膜对Bd的粘膜功能。因此，将在不同暴露于病原体的时间和不同海拔的几个人群中测试粘粒对Bd的功能。此外，将测试青蛙是否已经在蝌蚪阶段接受其益生菌皮肤微生物。此外，它将测试环境参数，如温度和光照有在迁地繁殖计划圈养繁殖两栖动物的粘液体功能的影响。