Figure 3. Expression of antimicrobial peptides and lysozyme in house flies after ingestion of GFP-Escherichia coli O157:H7.

Flies (total n = 95 in three biological replicates) were fed GFP-expressing E. coli O157:H7 (mean CFU ± SE: 1.40 ± 0.30 × 10⁶) and aseptically dissected at 2, 4, 6, and 12 h post-ingestion (n=7–8 per time point) to separate heads (with salivary glands), guts (i.e. proventriculus to rectum), and carcasses. qRT-PCR analysis was used to determine relative tissue-specific expression of cecropin (A), defensin (B), diptericin (C), and lysozyme (D) in house fly tissues (pooled per tissue within replicate). Log₂ fold change in expression was determined using the REST-MCS® software, with calibration to matched tissues from broth-fed control flies and the rps 18 reference gene. The mean expression of three biological replicates along with standard error is shown. Different letters denote statistical significance (P < 0.04) between tissues within time point. Asterisks denote statistical significance from broth-fed control flies (P < 0.05)