Identification andin silico characterisation of putative conjugative transfer genes on Geobacillus stearothermophilus plasmids

We report the first data demonstrating the presence of putative conjugative transfer genes on plasmids of the species Geobadllus stearothermophilus. Partial sequence analysis of the plasmid pGS18 from G. stearothermophilus 18 was determined. It contained eleven complete open reading frames. Five of them encoded proteins which are homologous to Bacillus megaterium pBM300 Mob/TraA, Lactococcus lactis pMRC01 TrsD and TrsE, Staphylococcus aureus pG01 TrsG and S. aureus subsp. aureus pUSA03 TraL, the proteins that are associated with conjugative plasmid transfer. Southern hybridizations were performed on two other plasmids isolated from G. stearothermophilus 3 and G. stearothermophilus 19 strains using the most homologous parts of those five genes as probes. Data from different hybridization patterns show a close homology of putative conjugative transfer genes between pGS and 8 pGS3 hypothesizing a similar molecular organization of putative conjugative plasmid transfer region of both plasmids.