FIG. 5.

CV staining assay of genetically (A) and chemically (B) complemented Y. pestis ΔspeA ΔspeC mutant. (A) The ΔspeA ΔspeC mutant was complemented by the expression of full-length speA from pBAD/HisbspeA. The speA⁺ speC⁺ strain and the ΔspeA ΔspeC mutant are included for comparison. (B) PMH2 medium was supplemented with 1 mM concentrations of putrescine, spermidine, or agmatine. CV staining values are the averages of three or more independent experiments, with error bars indicating standard deviations. The speA⁺ speC⁺ strain is included for comparison.