Behar A, Yuval B, Jurkevitch E
Department of Plant Pathology and Microbiology, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, 76100 Rehovot, Israel.
J Insect Physiol. 2008 Sep;54(9):1377-83. doi: 10.1016/j.jinsphys.2008.07.011. Epub 2008 Jul 26.
Fruit flies (Diptera: Tephritidae) harbor stable bacterial communities in their digestive system, composed mainly of members of the Enterobacteriaceae. However, the Enterobacteriaceae are not the sole community in this habitat. We examined the hypothesis that Pseudomonas spp. form a cryptic community in the gut of Ceratitis capitata, the Mediterranean fruit fly ('medfly'). Suicide polymerase restriction PCR (SuPER PCR), a novel culture-independent technique, revealed that Pseudomonas spp. form minor, common and stable communities within the medfly's gut. These include P. aeruginosa, a known pathogen of arthropods. Experimental inoculations with high levels of P. aeruginosa reduced the medfly's longevity while inoculations with members of the Enterobacteriaceae extended the fly's life. Accordingly, we suggest that in addition to their possible contribution to the fly's nitrogen and carbon metabolism, development and copulatory success (as shown in previous studies), the Enterobacteriaceae community within the medfly's gut may also have an indirect contribution to host fitness by preventing the establishment or proliferation of pathogenic bacteria.
果蝇（双翅目：实蝇科）在其消化系统中拥有稳定的细菌群落，主要由肠杆菌科成员组成。然而，肠杆菌科并非该栖息地的唯一群落。我们检验了这样一个假设：假单胞菌属在地中海实蝇（“地中海果蝇”）的肠道中形成一个隐秘群落。自杀聚合酶限制性PCR（SuPER PCR），一种新的非培养技术，揭示了假单胞菌属在地中海果蝇肠道内形成少量、常见且稳定的群落。这些群落包括铜绿假单胞菌，一种已知的节肢动物病原体。用高水平的铜绿假单胞菌进行实验接种会缩短地中海果蝇的寿命，而用肠杆菌科成员接种则会延长果蝇的寿命。因此，我们认为，除了它们可能对果蝇的氮和碳代谢、发育及交配成功有贡献（如先前研究所示）外，地中海果蝇肠道内的肠杆菌科群落还可能通过阻止病原菌的定殖或增殖对宿主健康有间接贡献。
