Fig. 1.
(a) Analysis of AvrA expression and secretion in vitro by Western blot. AvrA-tagged, SipA-tagged and SseJ-tagged strains of S. Enteritidis were grown under different culture conditions that mimicked the intestinal environment and the intracellular environment. Expression and secretion were investigated in whole bacterial extracts and supernatants, respectively. Samples were subjected to SDS-PAGE and tagged proteins were detected by anti-FLAG antibodies. Each lane was loaded with material from approximately 106 c.f.u. bacteria. Lanes: 1, SE1702 (avrA : : 3×FLAG cat : : FLAG); 2, SE1703 (sipA : : 3×FLAG cat : : FLAG); 3, SE1704 (sseJ : : 3×FLAG cat : : FLAG). Data are representative from three independent experiments. (b) Analysis of avrA expression under different culture conditions by qRT-PCR. The relative mRNA amount was determined by real-time qRT-PCR and related to 16S mRNA levels. Values are means±sd of three independent mRNA extractions performed in triplicate. AU, Arbitrary unit; NS, no significant difference between the two culture conditions (ANOVA). Black bars, intestinal environment; white bars, intracellular environment.