RESUMO
Two GATC specific methylases together with Sau3AI isoschizomeric restriction endonuclease were partially characterized in Mitsuokella multiacida 46/5. This is the first report on the presence of solitary Dam methyltransferase alongside GATC specific restriction-modification system resulting in the unusual two-fold methylation of the GATC motifs.
Assuntos
Bacteroidaceae/genética , Metilação de DNA , Metilases de Modificação do DNA/genética , Metilases de Modificação do DNA/metabolismo , Desoxirribonucleases de Sítio Específico do Tipo II/metabolismo , Eletroforese em Gel de ÁgarRESUMO
Analysis of restriction and modification activities in lactate-utilizing bacteria belonging to the Megasphaera elsdenii and Mitsuokella multiacida species revealed the presence of GATC-specific, MboI isospecific, restriction-modification (R-M) systems in all strains tested. While restriction endonucleases isolated from M. elsdenii strains were found to be sensitive to Dam methylation, enzymes from M. multiacida cleaved DNA irrespective of Dam methylation. The comparison of type II R-M systems specificities in three closely related lactate-utilizing ruminal bacterial species indicated complete lack of restriction and/or modification enzymes previously characterized from Selenomonas ruminantium in tested M. elsdenii and M. multiacida strains. R-M systems are believed to represent the main defense tool against phage infection. Based on the results of our experiments it could be assumed that M. elsdenii and M. multiacida use the different strategy for bacteriophage protection compared to S. ruminantium.
