A rapid method for preparation of rough and smooth lipopolysaccharide from Bacteroides, Porphyromonas and Prevotella

We describe a new method for lipopolysaccharide (LPS) preparation by water extraction at 100°C and subsequent digestion with proteinase K. The crude LPS could be reliably used for immunoblotting since it retained a high level of antigenicity, and was free of SDS and proteinase K, both of which can cause problems. Two monoclonal antibodies which failed to react with LPS prepared by two conventional methods reacted well with our preparation. We used the new method to prepare LPS from 44 strains of bacteria formerly classified as Bacteroides, some of which have been reclassified as Porphyromonas or Prevotella. In general, yields were good, and electrophoretic profiles obtained with SDS-PAGE and silver staining enabled strains to be rated rough, semi-rough, or smooth.