Figure 1. Dose-dependent killing of G. mellonella by S. Typhimurium NCTC 12023 WT.

G. mellonella larvae were infected with increasing bacterial loads, ranging from 40 to 4 × 10⁷ bacteria, and incubated for up to 50 h at 37° C. (A) Deposition of melanin at 2.5 h p. i. was dependent on the number of bacteria injected (1) PBS control; 2) non-injected control; 3) 4 × 10⁴; 4) 4 × 10⁵; 5) 4 × 10⁶; 6) 4 × 10⁷). (B) The percent of larvae surviving was assessed after injecting different doses of S. Typhimurium WT as indicated. Increasing amounts of dark-colored and/or dead larvae were obtained in a dose-dependent manner. PBS: buffer control. Data as shown are the representative results of three independent experiments, for which similar outcomes were obtained.