FIG. 1.

Western blot analysis of purine enzyme levels. Soluble proteins prepared from cells grown in antibiotic-free medium to the mid-logarithmic phase of growth were separated by SDS-polyacrylamide gel electrophoresis (PAGE). Proteins were transferred onto nitrocellulose membranes and probed with antibodies to PurH or antibodies to PurM as indicated. P100, strain 5827 passaged 100 times in the absence of vancomycin; strain 5827, first clinical VISA isolate in the United States; strains V20, V25, and VP-32, strain 5827 passaged on vancomycin to MICs of 20, 25, and 32 μg/ml, respectively.