GROUP-SPECIFIC 16S RIBOSOMAL-RNA HYBRIDIZATION PROBES FOR DETERMINATIVE AND COMMUNITY STRUCTURE STUDIES OF BUTYRIVIBRIO-FIBRISOLVENS IN THERUMEN

Oligonucleotide probes covering three phylogenetically defined groups of Butyrivibrio spp, were successfully designed and tested, The specif icity of each probe was examined by hybridization to rRNAs from an ass ortment of B. fibrisolvens isolates as well as additional ruminal and nonruminal bacteria. The sensitivity of the hybridization method was d etermined by using one of the probes (probe 156), When RNA was extract ed from a culture of OB156, the probe was able to detect target cells at densities as low as 10(4) cells/ml, When 10(4) or more target cells /ml were added to cattle rumen samples, detectable hybridization signa ls were obtained with 1,000 ng of total RNA loaded onto the nylon memb rane, In contrast, the sensitivity was reduced to 10(6) target cells/m l at 100 ng of RNA per slot, The probes were used to type 19 novel But yrivibrio isolates, The phylogenetic placement was confirmed by partia l 16S rRNA gene sequencing, The use of the probes in community-based s tudies indicated that the Butyvrivibrio groups examined in this paper did not represent a significant portion of the bacterial 16S rRNA pool in the rumen of the cattle, sheep, and deer examined.