An In Vivo Selection Identifies Listeria monocytogenes Genes Required to Sense the Intracellular Environment and Activate Virulence Factor Expression
Fig 2
Characterization of mutants identified in the genetic selection.
(A) Plaque area as a percentage of wild type. Data are the mean and error bars indicate the standard error of the mean (s.e.m.) for three independent experiments. p values were calculated using a heteroscedastic Student’s t-test and all strains are significantly different from wild type (p < 0.001). (B) Quantification of immunoblots of ActA and P60 during infection. ActA abundance was normalized to P60 abundance and measured as a percentage of wild type. Data are the mean ± s.e.m. of at least three independent experiments. (C) Female CD-1 mice were infected with 105 colony forming units (CFU) of each mutant. Spleens were harvested 48 hours post-infection and CFU were quantified. The solid lines indicate the median, and data represent three pooled experiments totaling n = 15 mice per strain. p values were calculated using a heteroscedastic Student’s t-test * p < 0.05; ** p < 0.01; *** p < 0.001. (D) Gene expression of target genes measured by quantitative RT-PCR in wild type L. monocytogenes grown in broth compared to expression during infection of BMMs. Data are the mean ± s.e.m. of at least three independent experiments. p values were calculated using a heteroscedastic Student’s t-test * p < 0.05.