FIG. 5.

Southern hybridization of M. arthritidis chromosomal DNA from 20 strains with probes prepared from DNA sequences in two different regions of ORF 1. Nine-microgram samples of chromosomal DNA were digested with EcoRI, electrophoresed on a 0.8% (wt/vol) agarose gel, transferred to nylon membrane, and hybridized with ³²P-labeled oligonucleotide probe NT, from near the 5′ end of the coding sequence (A), and a ³²P-labeled 264-bp HS fragment from within the ORF 1 repeat region (B). All 20 strains contained at least one copy of sequences homologous to NT, while only seven strains contained copies of the sequence from within the repeat region. These seven strains were shown in an earlier study to express the epitope recognized by MAA2-specific MAb 7a, while the others did not (54).