FIG. 1.

Colony morphology of SE6-HCD on inducing agar medium after serial passage. A 5-μl volume of cells of serovar Enteritidis maintained for two passages in early log phase and allowed to grow to stationary phase during the third passage was centrally inoculated on HEA–100 mM glucose. Plates were incubated for 16 h at 37°C. The diameter of the large terraced colony obtained from SE-HCD at its widest point is 62 mm. (Inset) Colony morphology of SE6-E21 transformed with pBR322 after serial passage (diameter, 8 mm), which is a phenotype similar to that of wild type lacking pBR322.