FIG 4.

PSM production in bovine mastitis isolates. PSMs were analyzed in culture filtrates of cultures inoculated from precultures and grown for 8 h in tryptic soy broth. HPLC-MS detection was performed essentially as described previously (23). Intensity values are based on the integration of the extracted ion chromatogram using the two most abundant m/z peaks of every single PSM. Intensities can thus be directly compared between strains for a specific PSM, but only in a limited way for different PSMs. The assay was performed in triplicate. Error bars show standard deviations.