PDF(Pubmed)
Abstract：
The microbiota is a key determinant of the physiology and immunity of animal hosts. The factors governing the transmissibility of viruses between susceptible hosts are incompletely understood. Bacteria serve as food for Caenorhabditis elegans and represent an integral part of the natural environment of C. elegans. We determined the effects of bacteria isolated with C. elegans from its natural environment on the transmission of Orsay virus in C. elegans using quantitative virus transmission and host susceptibility assays. We observed that Ochrobactrum species promoted Orsay virus transmission, whereas Pseudomonas lurida MYb11 attenuated virus transmission relative to the standard laboratory bacterial food Escherichia coli OP50. We found that pathogenic Pseudomonas aeruginosa strains PA01 and PA14 further attenuated virus transmission. We determined that the amount of Orsay virus required to infect 50% of a C. elegans population on P. lurida MYb11 compared with Ochrobactrum vermis MYb71 was dramatically increased, over three orders of magnitude. Host susceptibility was attenuated even further in the presence of P. aeruginosa PA14. Genetic analysis of the determinants of P. aeruginosa required for attenuation of C. elegans susceptibility to Orsay virus infection revealed a role for regulators of quorum sensing. Our data suggest that distinct constituents of the C. elegans microbiota and potential pathogens can have widely divergent effects on Orsay virus transmission, such that associated bacteria can effectively determine host susceptibility versus resistance to viral infection. Our study provides quantitative evidence for a critical role for tripartite host-virus-bacteria interactions in determining the transmissibility of viruses among susceptible hosts.
摘要：
微生物群是动物宿主生理和免疫的关键决定因素。控制病毒在易感宿主之间的传播性的因素尚未完全理解。细菌是秀丽隐杆线虫的食物，是秀丽隐杆线虫自然环境的组成部分。我们使用定量病毒传播和宿主敏感性测定，确定了从自然环境中分离出的C.elegans对Orsay病毒在C.elegans中传播的细菌的影响。我们观察到苍白杆菌属物种促进了奥赛病毒传播，而蓝藻假单胞菌MYb11相对于标准实验室细菌食品大肠杆菌OP50减毒病毒传播。我们发现致病性铜绿假单胞菌PA01和PA14进一步减毒病毒传播。我们确定，与灰白色杆菌属MYb71相比，感染50％的秀丽隐杆线虫种群所需的奥赛病毒数量急剧增加，超过三个数量级。在铜绿假单胞菌PA14的存在下宿主易感性甚至进一步减弱。对降低秀丽隐杆线虫对奥赛病毒感染的易感性所需的铜绿假单胞菌决定子的遗传分析揭示了群体感应调节剂的作用。我们的数据表明，秀丽隐杆线虫微生物群和潜在病原体的不同成分可以对奥赛病毒传播产生广泛不同的影响。这样相关细菌可以有效地确定宿主对病毒感染的易感性与抗性。我们的研究提供了定量证据，证明了三方宿主-病毒-细菌相互作用在确定病毒在易感宿主之间的传播性中的关键作用。
