Figure 2. Agr-like QS system regulation of C. perfringens toxin production involves a diffusible signal. (A) Inoculation of Transwell chambers with, as indicated, the type C parent strain CN3685, the isogenic cpb null mutant (CN3685::cpb) or an isogenic agrB null mutant (CN3685::agrB) in two chambers, or CN3685::cpb in one chamber and CN3685::agrB in the other chamber. After 5 h, CPB production in each culture was examined by CPB western blot. (B) Inoculation of Transwell chambers with, as indicated, type D parent strain CN3718, an isogenic etx null mutant (CN3718::etx) or an agrB null mutant (CN3718::agrB) in two chambers, or CN3718::etx in one chamber and CN3718::agrB in the other chamber. After 5 h, ETX production in each culture was examined by ETX western blot. Reproduced with permission from refs. 51 and 54.