Restriction fragment length polymorphism analysis of Bifidobacterium spp. and its application on identification of Korean isolates

초록

Bifidobacterium spp. are known to have several beneficial effects on human host. A number of Bifidobacteium spp. which were present as predominant populations in Korean adults were isolated. In order to identify the isolates, first we have established RFLP patterns for type strains of 12 bifidobacterial species obtained from ATCC by genomic Southern blot hybridization. A simple and rapid method was used for isolation of genomic DNA from bifidobacteria, which gave more than 20 microgram of DNA from a 3 ㎖ culture in less than 4 hours. After digestion with several restriction enzyme, genomic digests were fractionated on agarose gels prior to hybridization with 1,500 bp fragment within 16S rRNA gene as a probe. The probe has been amplified by PCR from genomic DNA of B. breve with eubacterial primers Southern hybridization revealed distinct RFLP patterns among bifidobacterial species. When all the isolates were identified as B. longum. In further identification experiments at the strain level, we have used 4 bp-cutting restriction enzymes to obtain RFLP patterns of 3 different strains of B. lonum along with those of Korean isolates, Interestingly, all the Korean isolates examined showed an identical RFLP pattern to that of B. longum ATCC 15708