Figure 1.

Mutual colicin induction. The proteins of isogenic strains carrying colicin E2 or E7 plasmids and a colicin-free control strain were crudely extracted and used to induce reporter strains carrying ce2a and ce7a promoters fused to the Photorhabdus luminescence luxCDABE reporter operon (Table 1). Colicin E2 crude protein extract was used to induce the pDEW-E7 reporter vector (A; filled circle), whereas colicin E7 extract was used to induce the pDEW-E2 reporter vector (B; filled triangle); the colicin-free strain was tested with the pDEW-E7 (C; open circle) and pDEW-E2 (D; open triangle) reporter vectors.