Figure 1
From: Intestinal FoxO signaling is required to survive oral infection in Drosophila
Oral infection with Serratia marcescens induces expression of antimicrobial peptide genes in different parts of the intestine and activates FoxO-dependent signaling. Shown are the responses of two transgenic lines indicating promotor activity of antimicrobial peptides (Defensin and Attacin) by concurrent expression of green fluorescent protein (GFP) in response to oral infection with S. marcescens. Controls fed with 5% sucrose did not show any signal in either the attacin- (a) or the defensin-reporter lines (c). Oral infection with Serratia induced attacin-associated expression primarily in parts of the proventriculus (b, arrow) and defensin-associated expression in various regions of the midgut (d, arrow). Oral infection with Serratia also induced activation of thor expression, which is a canonical FoxO target gene, as visualized using a thor-lacZ reporter strain (e and f, arrow). Transcript levels of various immune-related genes in response to oral infection with Serratia (6 h post infection) was quantified using quantitative real-time PCR (qRT-PCR) with isolated intestines from infected and control w1118and foxo21/21 adults (g; scale bars (a–f)=20 μm, in g, mean values±s.e.m. of four biological replicates are shown, *P<0.05, Mann–Whitney test).
