Restriction Endonuclease Analyses of Two Porcine Mycoplasma Deoxyribonucleic Acids: Sequence-Specific Methylation in the Mycoplasma hyopneumoniae Genome

The deoxyribonucleic acids of two porcine mycoplasmas, Mycoplasma hyopneumoniae and Mycoplasma flocculare, were distinguished readily with restriction enzymes. Enzymes that recognized guanine-plus-cytosine-rich sequences, such as SmaI and BamHI, were particularly useful since they generated relatively small numbers of deoxyribonucleic acid fragments which could be resolved by gel electrophoresis. In addition, we found that the adenine nucleotide in the GATC sequence of M . hyopneumoniae is methylated, whereas that in M. flocculare is not.