RECOMBINANT-DNA PROBES AND POLYMERASE CHAIN-REACTION FOR DETECTION OFMYCOPLASMA-GALLISEPTICUM STRAINS

Two recombinant DNA clones, pMG286.2 and pMG301.1, were isolated from the partial genomic library of Mycoplasma gallisepticum strain S6. Rec ombinant M. gallisepticum specific fragments were used as probes in So uthern hybridisation with 10 M. gallisepticum strains whose DNA was di gested by EcoRI, HindIII, BglII, RsaI and BamHI. The 1.5 kb fragment p MG301.1 did not show polymorphism in hybridisation patterns with M. ga llisepticum strains, while the 3.5 kb fragment pMG286.2 enabled differ entiation of M. gallisepticum strains into clusters. The DNA sequence of pMG301.1 was used to design a pair of 27-mer oligonucleotides flank ing a 1.3 kb genomic region. These two primers directed specific in vi tro amplification of all m. gallisepticum strains assayed giving an ex pected 1.3 kb product. Digestion of polymerase chain reaction products by DdeI enabled simple differentiation between clusters of M. gallise pticum strains and may be useful for improved epizootiological studies of M. gallisepticum infections in poultry.