Analysis of synonymous codon substitutions in the psm-mec ORF.

(A) The nucleotide sequence of the psm-mec ORF in pF and the synonymous codon substituted sequence of the psm-mec ORF in pFP are shown. The substituted nucleotides are colored in red. The amino acid sequence of PSM-mec protein is shown below the nucleotide sequence. (B) The amounts of psm-mec mRNA in Newman strains harboring pND50, pF, and pFP were measured. The data are presented as the means ± standard deviations from at least three independent experiments. ND, not detected. (C) The PSM-mec production of Newman strains harboring pND50, pF, or pFP was examined by HPLC. The data are presented as the means ± standard deviations from at least three independent experiments. ND, not detected. (D) The colony-spreading abilities of Newman strains harboring pND50, pF, or pFP were examined. Plates were incubated for 8 h at 37°C and the means ± standard deviations of the halo diameters from at least three independent experiments are shown. (E) The PSMα production of Newman strains harboring pND50, pF, or pFP was examined by HPLC. The data are presented as the means ± standard deviations from at least three independent experiments. (F) Biofilm formation onto polystyrene microplates of Newman strains harboring pND50, pF, or pFP was examined. (G) The PSMα production of Newman strains harboring the psm-mec gene-inducible plasmid (pNDX1-F) was examined. pNDX1-FP harbors the synonymous codon-substituted sequence of the psm-mec ORF in (A). ATc, anhydrotetracycline.