FIG. 1.

Comparison of the PS B1 and PS B2 biosynthesis regions of B. fragilis NCTC 9343 and 638R. The direction of transcription of each ORF (boxes) is designated with an arrow. The ORFs that do not demonstrate homology with genes involved in polysaccharide biosynthesis are shaded. The area between the diagonal lines indicates where the two chromosomes diverge. Two stem-loop regions that may serve to terminate transcription in the 638R region are indicated, as are the locations of primers used to amplify wcgC and wcgD for complementation studies. The average G+C content of each ORF of the 638R region is indicated by a black bar. Cosmid clones and a PCR product used as sequencing templates are shown.