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. 2014 Dec 1;111(52):18709–18714. doi: 10.1073/pnas.1413209111

Fig. 3.

Fig. 3.

Yersinia urease is responsible for toxicity to X. cheopis and O. montana fleas. (A) Y. pseudotuberculosis and Y. enterocolitica urease mutants are not toxic to fleas. Mortality of fleas 24 h after feeding on blood containing wild-type, ΔureD, ΔURE, or complemented ΔURE (pWKS-UREpstb) strains of Y. pseudotuberuclosis IP32953 (Y. pstb) or Y. enterocolitica 8081 (Y. ent). (B) Reactivation of the silenced urease activity in Y. pestis and expression of Y. pseudotuberculosis urease in Y. pestis and E. coli lead to flea toxicity. Mortality of fleas 24 h after feeding on blood containing wild-type Y. pestis KIM6+ with or without the empty cloning vector (WT, pWKS130), KIM6+ expressing the Y. pstb urease cluster (pWKS-UREpstb), or the Y. pstb ureG-D genes (pCR-ureGDpstb); KIM6+ in which the ureD pseudogene was repaired (ureDΔG); or E. coli containing the empty cloning vector (pWKS130) or expressing the Y. pstb IP32953 urease operon (pWKS-UREpstb). Data are the mean ± SD from a minimum of two experiments except for the strain E. coli (pWKS130) for which only one experiment was realized. ***P < 0.001, ****P < 0.0001, ★the value of both replicates was zero. The result of the in vitro urease test (+ or – phenotype after growth on urea agar) for each bacterial strain is indicated. N/A, not applicable.