FIG. 3.

The pH of the growth medium affects the secretion in culture of HrmA (HopPsyA) and HrpZ via the Hrp secretion system. P. syringae pv. syringae 61(pCPP2318) cultures were grown at 22°C in hrp-derepressing media differing only in the pH of the medium. Bacterial cultures were separated into cell-bound (C) and supernatant (S) fractions by centrifugation, and proteins were separated by SDS-PAGE. Immunoblot analysis was carried out as described in Materials and Methods, using anti-HrmA, anti-HrpZ, or anti-β-lactamase antibodies followed by secondary antibodies conjugated to alkaline phosphatase. The image of the immunoblot was captured by using the Bio-Rad Gel Doc 1000 UV fluorescent gel documentation system with the accompanying Multi-Analyst PC software. For figure construction, the image was manipulated by using Microsoft PowerPoint 97 and transferred to Adobe Photoshop 4.0 to meet the publisher’s specifications.