FIG 1.
Negative selection of L. monocytogenes mutants in vivo. Pregnant guinea pigs were injected i.v. with 109 CFU of the transposon mutant library. Bacteria surviving at 24 h p.i. in maternal liver (n = 4) and placenta (n = 8) were collected. The transposon mutants present in each sample were identified by microarray analysis. Data for the genes negatively selected in placenta only are represented. (A) Heat map of genes relatively absent in placenta versus BHI broth that are also not necessary for survival in the liver. Yellow represents a relative absence of the signal in the placenta compared with the liver, and blue represents a relative overabundance of the signal in the placenta compared with the liver. (B) Role category diagram representing the distribution of genes relatively absent in placenta, shown in panel A, according to gene ontology (GO) categories.