FIG 6.

Quantitative PCR analysis of genes involved in synthesis of surface polysaccharides. The parent strain W83, strain Δ77bpIR, and strain ΔPG0106 were grown to mid-log phase, and transcription of select genes was evaluated by qRT-PCR. (A) Transcription of K-antigen capsule synthesis genes (PG0108, PG0113, and PG0118) is not significantly altered by deletion of the 77bpIR element; however, PG0104, located upstream from the 77bpIR element, and PG0106, just down stream from the element, showed an increase in expression levels. Expression of the K-antigen capsule synthesis gene is downregulated in the ΔPG0106 K-antigen null mutant. (B) Genes reported to be associated with LPS synthesis are upregulated in the Δ77bpIR mutant. The cDNA samples analyzed for K-antigen capsule synthesis genes were further analyzed for changes in expression in genes associated with synthesis of LPS. Both PG1138 and PG1142, located in the PorR locus, have been reported to affect the presence of A-LPS. Error bars represent standard deviations of technical replicates.