Akami Mazarin, Tamgue Ousman, Ren Xueming, Wang Yaohui, Qi Xuewei, Martin Luther Koanga Mogtomo, Ngono Ngane Rosalie Annie, Niu Chang-Ying
Hubei Key Laboratory of Insect Resource Application and Sustainable Pest Control, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
Department of Biochemistry, Faculty of Science, University of Douala, PO Box 24157, Douala, Cameroon.
R Soc Open Sci. 2021 Nov 10;8(11):211104. doi: 10.1098/rsos.211104. eCollection 2021 Nov.
In order to understand the role of symbionts for their insect hosts, it is customary to treat them with antibiotics or to sterilize eggs (treatments), resulting in aposymbiotic and axenic insects, respectively. Such axenic insects can then be compared with untreated controls. Fruit flies often bear complex communities which are greatly reduced by such treatments. However, the bacterial community is not completely eliminated. Here, we examine the effect of these procedures on the structure of the remaining bacterial communities in (Diptera: Tephritidae) and on the insect longevity. The antibiotics (Norfloxacin and Ceftazedime) were administered to 1-day-old adult flies through sugar meal for 7 days, and eggs were surface sterilized and dechorionated to produce axenic lines. The flies were starved of protein before they were offered full diets or diets containing non-essential amino acids only. Antibiotic and egg disinfection treatments resulted in a significant reduction of the vast majority of gut bacterial populations, especially Proteobacteria, Firmicutes and Bacteroidetes. On the other hand, antibiotic allowed the persistence of Actinobacteria, Cyanobacteria and Acidobacteria populations. In untreated control flies, longevity was extended irrespective of diet quality in comparison to treated flies. Conversely, when gut bacteria were largely reduced (aposymbiotic and axenic flies), longevity was reduced in the non-essential amino acids diet treatment versus slightly improved in the presence of a protein diet. We discuss these results in an ecological-life-history perspective.
为了了解共生体对其昆虫宿主的作用，通常会用抗生素处理它们或对卵进行消毒（处理），分别产生无共生体和无菌昆虫。然后可以将这些无菌昆虫与未处理的对照进行比较。果蝇通常携带复杂的群落，这些群落在这种处理下会大大减少。然而，细菌群落并未被完全消除。在这里，我们研究了这些程序对地中海实蝇（双翅目：实蝇科）中剩余细菌群落结构以及昆虫寿命的影响。通过糖餐对1日龄的成年果蝇施用抗生素（诺氟沙星和头孢他啶）7天，并对卵进行表面消毒和去壳以产生无菌品系。在给果蝇提供全饲料或仅含非必需氨基酸的饲料之前，先使其饥饿缺乏蛋白质。抗生素和卵消毒处理导致绝大多数肠道细菌种群显著减少，尤其是变形菌门、厚壁菌门和拟杆菌门。另一方面，抗生素使放线菌门、蓝细菌门和酸杆菌门种群得以持续存在。在未处理的对照果蝇中，与处理过的果蝇相比，无论饲料质量如何，其寿命都会延长。相反，当肠道细菌大量减少时（无共生体和无菌果蝇），在非必需氨基酸饲料处理中寿命会缩短，而在有蛋白质饲料的情况下寿命略有改善。我们从生态生命史的角度讨论这些结果。
