Lee Hye-Yeon, Lee Shin-Hae, Lee Ji-Hyeon, Lee Won-Jae, Min Kyung-Jin
Department of Biological Sciences, Inha University, Incheon 22212, South Korea.
School of Biological Sciences, Seoul National University, Seoul 08826, South Korea.
Aging (Albany NY). 2019 Jul 12;11(13):4611-4640. doi: 10.18632/aging.102073.
Commensal microbes have mutualistic relationships with their host and mainly live in the host intestine. There are many studies on the relationships between commensal microbes and host physiology. However, there are inconsistent results on the effects of commensal microbes on host lifespan. To clarify this controversy, we generated axenic flies by using two controlled methods - bleaching and antibiotic treatment - and investigated the relationship between the commensal microbes and host lifespan in . The removal of microbes by using bleaching and antibiotic treatments without detrimental effects increased fly lifespan. Furthermore, a strain of flies colonized with a high load of microbiota showed a greater effect on lifespan extension when the microbes were eliminated, suggesting that commensal bacteria abundance may be a critical determinant of host lifespan. Consistent with those observations, microbial flora of aged fly gut significantly decreased axenic fly lifespan via an increase in bacterial load rather than through a change of bacterial composition. Our elaborately controlled experiments showed that the elimination of commensal microbes without detrimental side effects increased fly lifespan, and that bacterial load was a significant determinant of lifespan. Furthermore, our results indicate the presence of a deterministic connection between commensal microbes and host lifespan.
共生微生物与宿主存在互利关系，主要生活在宿主肠道内。关于共生微生物与宿主生理之间的关系已有许多研究。然而，共生微生物对宿主寿命的影响结果并不一致。为了澄清这一争议，我们通过两种可控方法——漂白和抗生素处理——培育了无菌果蝇，并研究了共生微生物与宿主寿命之间的关系。通过漂白和抗生素处理去除微生物且无有害影响，这延长了果蝇寿命。此外，当消除微生物时，携带高负荷微生物群的果蝇菌株对寿命延长的影响更大，这表明共生细菌丰度可能是宿主寿命的关键决定因素。与这些观察结果一致，老年果蝇肠道的微生物群通过增加细菌负荷而非改变细菌组成显著缩短了无菌果蝇的寿命。我们精心控制的实验表明，在无有害副作用的情况下消除共生微生物可延长果蝇寿命，且细菌负荷是寿命的重要决定因素。此外，我们的结果表明共生微生物与宿主寿命之间存在确定性联系。
