FIG 1.

Differences between S. Pullorum (SP) and S. Enteritidis (SE) in their intracellular survival dynamics (A and B), NO production (D), and iNOS expression (E) in infected chMDMs do not correlate with their effect on the viability of infected chMDMs (C). (A and B) Infected chMDMs were lysed to quantify intracellular viable bacteria (A) and the decline rate (B). (D) The supernatant was collected to determine the nitrite ion concentration using a Griess assay. (E) Relative mRNA expression levels of iNOS shown as fold changes in comparison to those from uninfected chMDMs (shown as 1) at 6 h p.i. (C) Percentages of viable chMDMs infected with S. Pullorum and S. Enteritidis were determined by using propidium iodide. Data in panels A, C, and D are presented as means ± standard errors of the means (SEM) (n = 3) and are representative of results from at least two independent experiments. For panel B, the decline rate was determined by using averaged counts of intracellular viable bacteria at each time point. For panel E, iNOS levels were determined from chMDMs prepared from three birds. + indicates a statistically significant difference from the negative control (+, P < 0.05; ++, P < 0.01). * indicates statistical differences between different treatment (*, P < 0.05; **, P < 0.01).