School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland.
Microbiology (Reading). 2020 Apr;166(4):335-348. doi: 10.1099/mic.0.000907. Epub 2020 Mar 24.
Different model systems have, over the years, contributed to our current understanding of the molecular mechanisms underpinning the various types of interaction between bacteria and their animal hosts. The genus comprises Gram-negative insect pathogenic bacteria that are normally found as symbionts that colonize the gut of the infective juvenile stage of soil-dwelling nematodes from the family . The nematodes infect susceptible insects and release the bacteria into the insect haemolymph where the bacteria grow, resulting in the death of the insect. At this stage the nematodes feed on the bacterial biomass and, following several rounds of reproduction, the nematodes develop into infective juveniles that leave the insect cadaver in search of new hosts. Therefore has three distinct and obligate roles to play during this life-cycle: (1) must kill the insect host; (2) must be capable of supporting nematode growth and development; and (3) must be able to colonize the gut of the next generation of infective juveniles before they leave the insect cadaver. In this review I will discuss how genetic analysis has identified key genes involved in mediating, and regulating, the interaction between and each of its invertebrate hosts. These studies have resulted in the characterization of several new families of toxins and a novel inter-kingdom signalling molecule and have also uncovered an important role for phase variation in the regulation of these different roles.
多年来，不同的模式系统为我们目前对细菌与其动物宿主之间各种类型相互作用的分子机制的理解做出了贡献。 属包含革兰氏阴性昆虫致病性细菌，通常作为共生体存在，定植于土壤线虫科感染性幼虫阶段的肠道中。线虫感染易感昆虫，并将细菌释放到昆虫血淋巴中，细菌在那里生长，导致昆虫死亡。在这个阶段，线虫以细菌生物量为食，并且在多次繁殖后，线虫发育成感染性幼虫，离开昆虫尸体寻找新的宿主。因此， 在生命周期中有三个截然不同且必需的作用：(1) 必须杀死昆虫宿主；(2) 必须能够支持线虫的生长和发育；(3) 必须能够在下一代感染性幼虫离开昆虫尸体之前定植于其肠道中。在这篇综述中，我将讨论遗传分析如何确定参与 与其每个无脊椎动物宿主之间相互作用的关键基因，并对其进行调节。这些研究导致了几类新毒素家族和一种新型的跨领域信号分子的表征，并且还揭示了相位变化在调节这些不同作用中的重要作用。
