16S rDNA analysis of bacterial diversity in three fractions of cow rumen

examined using a PCR-based approach. 16S rDNA sequenceswere amplified and cloned from thre fractions of rumen(solid, fluid, and epithelium) that are likely to representdiferent bacterial niches. A total of 113 clones weresequenced, and similarities to known 16S rDNA sequenceswere examined. About 47.8% of the sequences had 90-97%similarity to 16S rDNA database sequences. Furthermore, about62.2% of the sequences were 98-100% similar to 16S rDNAdatabase sequences. For the remaining 6.1%, the similarityinfer the makeup of the bacterial comunities in the differentrumen fractions. The Cytophaga-Flexibacter-Bacteroides group(CFB, 67.5%), low G+C Gram-positive bacteria (LGCGPB,30%), and Proteobacteria (2.5%) were represented in therumen fluid clone set; LGCGPB (75.7%), CFB (10.8%),Proteobacteria (5.4%), high G+C Gram-positive bacteria(HGCGPB, 5.4%), and Spirochaetes (2.7%) were representedin the rumen solid clone set; and the CFB group (94.4%) andclone set. These findings sugest that the rumen fluid, solid,and epithelium suport diferent microbial populations thatmay play specific roles in rumen function. KCI Citation Count: 30