Osmolality as a Novel Mechanism Explaining Diet Effects on the Outcome of Infection with a Blood Parasite.
Osmolality as a Novel Mechanism Explaining Diet Effects on the Outcome of Infection with a Blood Parasite.
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渗透压作为一种新机制解释饮食对血液寄生虫感染结果的影响。
DOI：
10.1016/j.cub.2020.04.058
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Wilson K
中科院分区：
文献类型：
--
作者：
Wilson K
最近的研究表明，宿主-寄生虫相互作用的结果取决于宿主的饮食，但以往的研究大多集中在自上而下的机制上，即宿主的饮食如何改善宿主的免疫反应，以降低寄生虫的数量，改善宿主的健康状况。相比之下，寄主营养对寄生虫适合性的直接影响以及支持这些影响的机制相对来说还没有被探索。在这里，我们使用一个模型宿主-病原体系统(斜纹夜蛾和嗜线虫，一种细胞外细菌血液寄生虫)，在体外和体外探索宿主膳食中大量营养素平衡对病原体生长速度的影响，使我们能够比较存在和不存在宿主免疫反应时的病原体生长速度。在体内，高蛋白饲料导致较低的细菌建立率、较慢的细菌生长速度、较高的宿主存活率和较慢的宿主死亡速度；相反，食物中碳水化合物的能量含量和数量解释了任何衡量病原体或宿主适合性的指标几乎没有变化。在体外，我们表明这些影响在很大程度上是由宿主饲料蛋白对宿主血淋巴(血液)渗透压(即其溶质浓度)的影响驱动的，在富含蛋白质、高渗透压血淋巴中细菌生长较慢，这突显了一种新的“自下而上”的机制，通过这种机制，宿主饮食可以同时影响病原体和宿主适合度。
Recent research has suggested that the outcome of host-parasite interactions is dependent on the diet of the host, but most previous studies have focused on "top-down" mechanisms, i.e., how the host's diet improves the host immune response to drive down the parasite population and improve host fitness. In contrast, thedirectimpacts of host nutrition on parasite fitness and the mechanisms underpinning these effects are relatively unexplored. Here, using a model host-pathogen system (Spodoptera littoraliscaterpillars andXenorhabdus nematophila, an extracellular bacterial blood parasite), we explore the effects of host dietary macronutrient balance on pathogen growth rates bothin vivoandin vitro, allowing us to compare pathogen growth rates both in the presence and absence of the host immune response.In vivo, high dietary protein resulted in lower rates of bacterial establishment, slower bacterial growth, higher host survival, and slower speed of host death; in contrast, the energy content and amount of carbohydrate in the diet explained little variation in any measure of pathogen or host fitness.In vitro, we show that these effects are largely driven by the impact of host dietary protein on host hemolymph (blood) osmolality (i.e., its concentration of solutes), with bacterial growth being slower in protein-rich, high-osmolality hemolymphs, highlighting a novel "bottom-up" mechanism by which host diet can impact both pathogen and host fitness.