Heys Chloe, Lizé Anne, Blow Frances, White Lewis, Darby Alistair, Lewis Zenobia J
School of Life Sciences/Institute of Integrative Biology University of Liverpool Liverpool UK.
UMR 6553 ECOBIO University of Rennes Rennes France.
Ecol Evol. 2018 Mar 26;8(8):4150-4161. doi: 10.1002/ece3.3991. eCollection 2018 Apr.
In recent years, there has been a surge in interest in the effects of the microbiota on the host. Increasingly, we are coming to understand the importance of the gut microbiota in modulating host physiology, ecology, behavior, and evolution. One method utilized to evaluate the effect of the microbiota is to suppress or eliminate it, and compare the effect on the host with that of untreated individuals. In this study, we evaluate some of these commonly used methods in the model organism, . We test the efficacy of a low-dose streptomycin diet, egg dechorionation, and an axenic or sterile diet, in the removal of gut bacteria within this species in a fully factorial design. We further determine potential side effects of these methods on host physiology by performing a series of standard physiological assays. Our results showed that individuals from all treatments took significantly longer to develop, and weighed less, compared to normal flies. Males and females that had undergone egg dechorionation weighed significantly less than streptomycin reared individuals. Similarly, axenic female flies, but not males, were much less active when analyzed in a locomotion assay. All methods decreased the egg to adult survival, with egg dechorionation inducing significantly higher mortality. We conclude that low-dose streptomycin added to the dietary media is more effective at removing the gut bacteria than egg dechorionation and has somewhat less detrimental effects to host physiology. More importantly, this method is the most practical and reliable for use in behavioral research. Our study raises the important issue that the efficacy of and impacts on the host of these methods require investigation in a case-by-case manner, rather than assuming homogeneity across species and laboratories.
近年来，人们对微生物群对宿主的影响兴趣激增。我们越来越认识到肠道微生物群在调节宿主生理、生态、行为和进化方面的重要性。一种用于评估微生物群作用的方法是抑制或消除它，并将对宿主的影响与未处理个体进行比较。在本研究中，我们在模式生物中评估了一些常用方法。我们采用全因子设计，测试了低剂量链霉素饮食、去卵壳处理以及无菌饮食在去除该物种肠道细菌方面的效果。我们通过进行一系列标准生理测定，进一步确定这些方法对宿主生理的潜在副作用。我们的结果表明，与正常果蝇相比，所有处理组的个体发育时间显著延长，体重更轻。经过去卵壳处理的雄性和雌性果蝇体重明显低于链霉素饲养的个体。同样，在运动测定中分析时，无菌雌性果蝇（而非雄性）的活动能力明显较低。所有方法都降低了卵到成虫的存活率，去卵壳处理导致的死亡率显著更高。我们得出结论，在饮食培养基中添加低剂量链霉素在去除肠道细菌方面比去卵壳处理更有效，并且对宿主生理的有害影响较小。更重要的是，这种方法在行为研究中是最实用和可靠的。我们的研究提出了一个重要问题，即这些方法对宿主的有效性和影响需要逐案研究，而不是假设跨物种和实验室具有同质性。
