Extracellular DNA from Serpulina hyodysenteriae consists of 6.5 kbp random fragments of chromosomal DNA

Abstract

Preparations of chromosomal DNA from a number of Serpulinahyodysenteriae strains have shown, using agarose gel electrophoresis,the presence of an additional band with a mobility similar to that of a6.5 kbp linear DNA fragment. Analysis showed that this is not a plasmidbut rather a form of extracellular DNA like that observed forGram-negative bacteria. However, unlike the extracellular DNA fromGram-negative bacteria, which showed a similar band profile to that ofthe DNA from whole cells, that from S. hyodysenteriae consistedprimarily of fragments of a fixed 6.5 kbp.