From phalanx to assassins: The commensal-to-pathogen switch in the lepidopteran gut microbial community

在许多动物中，细菌的数量远远超过动物细胞的数量。动物和细菌之间的联系大多是良性的，有些是有益的，但在某些情况下，共生(良性)细菌会转化为病原体，导致心内膜炎和败血症等疾病。人们对这种转换知之甚少，但可能涉及宿主生理或免疫状态的变化，或者细菌进入它们通常不居住的器官。动物肠道是经历从共生到病原体转换的细菌的常见来源，但许多动物肠道中微生物群落的复杂性为研究肠道群落与宿主的相互作用导致健康状况的变化提供了障碍。研究人员将研究一种常见的毛虫--吉普赛蛾的幼虫--正常肠道居民从共生到病原体的转换。该项目旨在了解基本的生态相互作用，使一种吉普赛蛾肠道菌群的正常成员能够在另一种细菌产生的毒素存在的情况下煽动疾病和死亡。这项研究将检验这样的假设，即向病原体的转换与宿主的炎症反应有关，以及肠道正常微生物群落介导了共生向病原体的转换。该项目将为历史上黑人大学的本科生提供暑期研究体验。他们将从参与研究的大学中以队列的形式招募，以便在研究计划期间为他们提供一个同行小组。暑期学生的所有导师都将在课程中接受培训，进入由PI开发的导师培训，以确保每个学生都有成功的研究体验。

In many animals, bacteria vastly outnumber of animal cells. Most of the associations between animals and bacteria are benign and some are beneficial, but under some circumstances, commensal (benign) bacteria convert to pathogens, resulting in diseases such as endocarditis and sepsis. This switch is poorly understood, but may involve changes in host physiology or immune status or bacterial entry into organs where they normally do not reside. The animal gut is a common source of bacteria that undergo the commensal-to-pathogen switch, but the complexity of the microbial communities in many animals' guts presents a barrier to studying the gut community's interactions with the host that lead to the change in health status. The investigators will study the commensal-to-pathogen switch of normal gut residents in a common caterpillar, the larva of the gypsy moth. The project aims to understand the fundamental ecological interactions that enable a bacterium that is a normal member of the gypsy moth gut flora to incite disease and death in the presence of a toxin produced by another bacterium. The study will test the hypotheses that the conversion to pathogen is associated with host's inflammatory response and that the normal microbial community of the gut mediates the commensal-to-pathogen switch. The project will provide the context for providing summer research experiences for undergraduate students from historically black universities. They will be recruited from participating universities in cohorts to provide them a peer group during the research program. All mentors of the summer students will be trained in the course, Entering Mentoring, which was developed by the PI, to ensure a successful research experience for every student.