Pirellulosomes: a new type of membrane-bounded cell compartment in planctomycete bacteria of the genus Pirellula

The structure and nucleic acid content of pirellulosomes were analyzed in planctomycetes such as Pirellula marina and Gemmata obscuriglobus. Electron microscopic analysis of pirellulosomes indicated the presence of genomic DNA in the membrane-bounded cell organelle. Furthermore, the membrane-bounded DNA-containing region in Pirellula marina contains single membrane while the pirellulosome in Gemmata obscuriglobus has two membranes.