FIG. 1.

(A) O-PS structure of serotype b A. actinomycetemcomitans. (B) Silver-stained 5 to 15% polyacrylamide-SDS gel of serotype b LPS. A total of 1.0 ml of mid-logarithmic-phase cells were collected and lysed. Three lysates from each strain were combined and treated with proteinase K at 60°C for 60 min before electrophoresis, followed by silver staining. C, control: whole-cell lysate without proteinase K digestion; WT, wild type (VT1169); emaA, extracellular matrix protein adhesin A mutant; rmlC, rhamnose epimerase mutant; wzt, ATP-binding cassette sugar transport mutant. The dark brown staining of the high molecular weight (75,000 to 250,000) corresponds to polymerized O-PS.