FIG. 4.

Estimation of the contribution of Bacteroides and Prevotella 16S rDNA to total eubacterial 16S rDNA sequences. Amplified sequences were transferred onto a filter by Southern blotting and probed with either the Uni16S eubacterial probe (A) or the BacPre probe (B). Lanes: 1, amplified DNA from P. ruminicola 23 control; 2 to 5, DNA from four different sheep rumen samples. To obtain the data shown in the final columns in Tables 2 and 3, radioactivity was estimated for each band by using a Packard beta scanner. The proportion of eubacterial 16S rDNA sequences due to Bacteroides and Prevotella was estimated as (a_e/a_b) × (b_b/b_e) where a_e and b_e are the counts obtained for the control and unknown cultures, respectively, with the universal eubacterial probe uni16S, and a_b and b_b are the corresponding counts obtained with the BacPre probe.