FIG. 4.

PCR analysis. Gentamicin-resistant or chloramphenicol-resistant N. meningitidis B16B6 colonies were selected for PCR analysis, and PCR products were separated by electrophoresis. Products in lanes 1 to 4 were obtained with primers 513 and 539 (Table 1), which flank the ClaI site of the lbpB gene. Products in lanes 5 to 8 were obtained with primers 536 and 537, which flank the unique SalI site of the lbpB gene. Lanes 9 to 12 were obtained with primers 287 and 212, which flank the EagI site of the meningococcal lbpA gene (39). The PCR product in lane 13 was obtained with primer 262, which is specific for the 5′ end of the gent cassette, and primer 539, which is specific for the lbpA gene (39). Lane 14 contains the PCR product obtained with primer 536, which is specific for the 5′ end of the lbpB gene, and primer 395, which is specific for the 3′ end of the catΩ gene (22). The PCR product in lane 15 was obtained with primers 287 and 394, which are specific for regions upstream of the 3′ end of the catΩ gene (22). Lanes 1, 5, and 9, N16T12EK; 2, 6, 10, and 13, N16T12EK lbpB::gent; 3, 7, 8, and 14, N16T12EK lbpB::catΩ; 4, 8, 12, and 15, N16T12EK lbpA::catΩ. A negative image of the ethidium bromide-stained agarose gel is shown. STDS, molecular weight standards.