A high degree of genetic diversity among 29 strains of from the rumen was revealed by comparing restriction fragment length polymorphisms in 16S rRNA genes, sodium dodecyl sulfate-polyacrylamide gel profiles of total-cell proteins, and G+C contents of chromosomal DNAs. In order to obtain information on phylogenetic relationships, the sequences of a 389-bp region of the 16S rRNA gene, including variable regions 4 and 5, were compared for 10 strains. These 10 strains formed a single group when their sequences were compared with 16S ribosomal DNA sequences from other species, including spp. from the human colon. On the other hand, the great genetic distances between many strains, including subsp. B4 and GA33 and 23 (T = type strain), support the hypothesis that these organisms should be reclassified into new species. We identified signature oligonucleotides based on 16S ribosomal DNA sequences that distinguished strains related to strains 23, B4, GA33, and M384, as well as an oligonucleotide that specifically recognized all but one of the and strains tested. On the basis of the priming activities of these signature oligonucleotides in PCR reactions and on other criteria, we concluded that 12 of the original 29 strains were related to strain 23, 4 were related to strain B4, and 4 were related to strain GA33. While there are clear grounds for subdividing the species on the basis of genotypic differences, it is appropriate to delay formal reclassification until further work on the phenotypic differentiation of the new groups is completed.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error