Characterization of Spiroplasmas by one- and two-dimensional protein analysis on polyacrylamide slab gels

Abstract

Differences betweenSpiroplasma citri isolates were detected by one-dimensional electrophoresis of proteins on gradient polyacrylamide slab gels. Two-dimensional protein maps (electrofocusing followed by electrophoresis) showed a highly characteristic pattern for allS. citri isolates examined. Coanalysis of mixed protein samples from pairs ofS. citri strains revealed more than 150 comigrating proteins common to allS. citri isolates, but also a number of noncomigrating proteins. Some noncomigrating proteins were present in one isolate but not in another, while other proteins whose migrational properties were only slightly different from one isolate to the other (homologous proteins), were present in more than one isolate.S. citri isolates had many common and only a few homologous proteins. Comparisons ofS. citri with the corn stunt spiroplasma revealed few common proteins and a large number of homologous proteins. When comparingS. citri and the suckling mouse cataract spiroplasma, few common and homologous proteins were apparent. However, several of these common proteins were also shared by the corn stunt spiroplasma, suggesting that they may well represent genus-specific proteins. The data also offer additional evidence that the suckling mouse cataract spiroplasma differs significantly fromS. citri and corn stunt spiroplasmas and probably deserves a separate species designation.