FIGURE 1.

Co-cultivation of C. jejuni with viable epithelial cells stimulates enhanced metabolic activity. Temporal kinetics of [³⁵S]-methionine incorporation by C. jejuni strains 81–176 (A) and F38011 (B) incubated in MEM, MEM plus 1% FBS, MEM with human INT 407 epithelial cells that had been fixed with paraformaldehyde, MEM with viable human INT 407 epithelial cells, and MEM plus 1% FBS and viable human INT 407 epithelial cells. The FBS used in these experiments was albumin-depleted and dialyzed against PBS. The [³⁵S]-methionine labeling was performed in the presence of emetine hydrochloride to prevent radioactive methionine incorporation by the host cells. The bacteria were pelleted at the end of the time intervals indicated, washed in PBS, and amount of [³⁵S]-methionine incorporation determined by measuring counts per minute following trichloroacetic acid (TCA) precipitation. Shown is the mean ± the standard deviations. Significant differences from the MEM alone at each time point were determined by one-way ANOVA followed by Sidak’s multiple comparisons test (^∗p < 0.05).