Comparison of two Lactobacillus strains isolated from piglets in different area by using representational difference analysis

Abstract:

[Objective] To identify Lactobacillus sp. strain S1 from the intestine of piglet, and compare the genomic difference between this strain and Lactobacillus sobrius 001T. [Methods] Analysis of 16S rRNA gene sequence and species-specific polymerase chain reaction assay were used to identify Lactobacillus sp. strain S1. Representational difference analysis (RDA) was used to compare these two strains. [Results] The 16S rRNA gene sequence analysis of strain S1 showed that its closest known species in the GenBank database was L. sobrius. Denaturing gradient gel electrophoresis analysis showed that the predominant bands in profiles from bacteria in the jejunum and ileum of piglets had the identical migrating position with strain S1. Cloning and sequencing of 16S rRNA gene analysis revealed that this band matched clone (Clone S) was also related closely to L. sobrius. Phylogenetic analysis of 16S rRNA gene showed that homology between strain S1 and Clone S was 99.8%, and that between strain S1 and L. sobrius was 99.6%. Both strains could be detected in 1.2% agarose gel by L. sobrius-specific PCR assay. Recently, RDA has been adapted to study the genomic diversity of bacterial strains. This analysis showed that there was no genomic difference between the two strains. [Conclusion] Piglet-derived strain S1 belonged to L. sobrius. Piglet-derived L. sobrius 001T and L. sobrius S1 were the similar strain.