FIG. 4.

Role of LPS phenotype in serum resistance of Y. enterocolitica O:9. Survival of bacteria in 66.7% NHS (CP/AP-killing bottom panel) and Mg-EGTA-treated serum (AP-killing, top panel) at 0.5- and 2-h time points. The columns indicate the mean survival percentage of the strain, and the bars indicate the ranges of standard errors. The filled columns show the results for the wild-type strain. In between the panels, the strains and their properties with respect to the presence of pYV (Yersinia virulence plasmid) and expression of OPS and OC are indicated. *, the AP killing results of YeO9-OC and YeO9-R1 at 2 h differed significantly (P < 0.001, Student's t test) from those of Ruokola/71.