GENETIC-BASIS OF PYOCIN RESISTANCE IN NEISSERIA-GONORRHOEAE

The genetic basis for pyocin resistance in Neisseria gonorrhoeae 1291( d), 1291(e), and FA5100 was determined by Southern blot and DNA sequen ce analyses. The genes defective in these strains are present as singl e copies in the gonococcal chromosome. The mutant regions of 1291(d), 1291(e), and FA5100 were amplified by the PCR. Sequence analysis of th e mutant regions demonstrated that strain 1291(d) contains a 12-bp del etion that results in the loss of four amino acids in phosphoglucomuta se, while strain 1291(e) contains a point mutation that results in the change of an uncharged glycine residue to a charged glutamic acid res idue in the same protein. FA5100 contains a nonsense mutation in the g ene encoding heptosyltransferase II. The gene previously described as lsi-1 was Shown to complement an rfaF mutation in Salmonella typhimuri um and has been renamed rfaF.