Zombie Ants: Towards a Mechanistic Understanding of the Precise Control of Animal Behavior by a Microbial Parasite

僵尸蚂蚁：从机制上理解微生物寄生虫对动物行为的精确控制

• 批准号: 1558062
• 负责人: David Hughes
• 金额: $ 54.7万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-02-15 至 2019-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1558062&HistoricalAwards=false
• 关键词: Zombie; Ants; Towards; Mechanistic; Understanding

One of the most complex examples of symbiosis in nature is the precise manipulation of animal behavior by a microbe. Ophiocordyceps is a fungus that infects zombie ants. Infection of ant workers by thousands of these fungal cells causes the workers to leave the colony and die attached by their mandibles to plants that overhang the trails of ant colonies. There the fungus uses the dead ant bodies to produce spores that infect other ants. The manipulation is complex and spectacular given the fact that an organism without a brain controls the behavior of one with a brain. In this project the research team will use an integrative approach to ask how fungi change ants from being productive members of their colony to "fungi in ant's clothing?". The project will use measurement of gene expression, metabolism and tissue structure to ask how, during the 3 week period of infection, the fungi effectively take control of the ant. This work will provide many general insights into the nature of parasitism and may have broader societal relevance because these fungi are known to be important sources of small molecules with medical relevance. The work is relevant to the broader mission of NSF to increase scientific literacy as the zombie ant system has been shown to be a very useful tool for communicating the elegance and beauty of natural systems. How can a microbe control the central nervous system of an animal? Animals are intimately associated with microbes that span the symbiotic spectrum from mutualism to parasitism. In some cases, microbial parasites of animals have evolved to control animal behavior in ways that enhance parasite transmission. The zombie ants represent one prominent example. In this system a fungal parasite (Ophiocordyceps unilateralis) has evolved a precise level of behavioral control over the ants it infects. Worker ants infected by O. unilateralis move out from their colonies at precise times of day to highly specific locations on leaves in forests, where they bite into vegetation before dying. This altered behavior provides a platform for the eventual release of spores from a long fungal stalk that grows from the cadaver of the ant. This striking system involves an organism in one kingdom of life (Fungi) that controls the behavior of an organism in another (Animalia). How does an organism without a brain control the behavior of one with a brain? The investigators will address this using time series infectionstudies to measure chemical changes in both the parasite and its host. By using three different but complementary tools (serial block face scanning electron microscopy, metabolomics and transcriptomics) to examine these changes across time, the investigators hope to understand the basis of these behavioral changes.

自然界中共生最复杂的例子之一是微生物对动物行为的精确操纵。 Ophiocordyceps是一种感染僵尸蚂蚁的真菌。 成千上万的这些真菌细胞对蚂蚁工人的感染导致工人离开殖民地，并由其下颌骨附着在悬挂着蚂蚁菌落痕迹的植物上。真菌在那里使用死蚂蚁物体产生感染其他蚂蚁的孢子。鉴于没有大脑的有机体控制一个人的行为，这种操作是复杂而壮观的。在这个项目中，研究团队将采用一种综合方法来询问真菌如何从其殖民地的生产成员变成“蚂蚁服装中的真菌？”。该项目将使用基因表达，代谢和组织结构的测量，以询问在感染的3周期间，真菌如何有效地控制蚂蚁。 这项工作将提供许多对寄生虫本质的一般见解，并且可能具有更广泛的社会意义，因为这些真菌是具有医学相关性的小分子的重要来源。这项工作与NSF的更广泛的使命有关，以提高科学素养，因为僵尸蚂蚁系统已被证明是传达自然系统的优雅和美丽的非常有用的工具。微生物如何控制动物的中枢神经系统？动物与跨越共生频谱的微生物密切相关，从互惠到寄生虫。在某些情况下，动物的微生物寄生虫已经演变为以增强寄生虫传播的方式来控制动物行为。僵尸蚂蚁代表了一个突出的例子。 在该系统中，真菌寄生虫（Ophiocordyceps Unilferalis）已进化出对IT蚂蚁感染的蚂蚁的精确行为控制水平。由O. Unilferalis感染的工人蚂蚁在一天中的精确时间从其菌落中移出，转移到森林中的叶子上高度特定的位置，在森林中，它们在死后咬成植被。这种改变的行为为从蚂蚁的尸体生长的长真菌茎中最终释放孢子提供了一个平台。这个引人注目的系统涉及一个生命王国（真菌）中的生物，该生物控制着一种生物在另一种生物（Animalia）中的行为。 没有大脑的有机体如何控制一个人的行为？ 研究人员将使用时间序列感染研究人员来解决这一问题，以测量寄生虫及其宿主的化学变化。 通过使用三种不同但互补的工具（串行块面扫描电子显微镜，代谢组学和转录组学）来检查这些变化，研究人员希望了解这些行为变化的基础。