Poulsen A, Kobayasi T, Secher L, Weismann K.
DOI: 10.2340/0001555565367373

The ultrastructure of treponema pallidum obtained directly from human chancres by biopsy was studied by electron microscopy. The treponemes were enveloped by a trilaminar cytoplasmic membrane and a trilaminar periplastic membrane. The central part of the periplastic membrane corresponds to the protective mucoid layer. In undamaged organisms bunches of axial filaments were seen to entwine the whole cytoplasmic body without any disruption or overlapping. The number of axial filaments varied between three and four. Identical nose pieces were demonstrable in both ends of the treponemes. Axial filaments and nose pieces seem to differ from those of Nichols´ strain.