FIG. 2.

(A) Carriage of exl loci in meningococcal genomes is mutually exclusive. Southern blots of 10 meningococcal strains hybridized with hmbR, exl2, and exl3 probes are shown. Lanes 1 through 10 contain genomic DNAs from strains NMB, 44/76, 6940, M981, FAM18, M1205, M1843, F8229, GA0929, and 6083, respectively. Lane L contains labeled size markers, and lane P contains unlabeled probe DNA as a positive control. (B) Genetic arrangement of the exl cassettes in N. meningitidis strainsGA0929 (accession number AF319532) and 6083 (accession number AF319533). See the legend to Fig. 1 for details.