FIG 8 .

Closely related Clostridium species are involved in the production of the inhibitory molecules. (A) Strains from diverse Clostridium species were tested for biological activity against hilA. Strains were cultured under anaerobic conditions in Trypticase soy broth supplemented with menadione and hemin for at least 2 days, and the cultures were extracted with ethyl acetate. Dried extracts were added to LB broth, which was used to culture a Salmonella hilA::gfp reporter strain. GFP production was then monitored through flow cytometry. Results shown are the averages of three individual measurements (n = 3), except for the control culture, where six cultures were used (n = 6). Bars indicate the standard errors of the means. (B) Production of the inhibitory molecule by select Clostridium strains was confirmed through RT-PCR targeting hilA. Results shown are the averages of 2 to 6 individual measurements, and bars show the standard errors of the means. *, P < 0.03; ns, not significant (P > 0.05).