Existence of a surface configuration on the aerial spore and aerial mycelium of Micropolyspora.

We report the existence of a surface configuration in a true spore-forming genus having cell wall constituents of type IV. Micropolyspora angiospora, M. caesia and M. faeni freeze-fractured along the wall surface and only had a surface configuration on their aerial mycelium and aerial spores, with none on the substrate mycelium and substrate spore. The surface configuration of Micropolyspora was distinctly more complicated than that of Nocardia. The aerial spores of M. angiospora were characteristic in that they possessed ridges, two kinds of surface configurations (i.e. rodlets and fibres), and a complex pattern on the surface. Some rodlets of this organism were formed of a two-stranded helix, each strand having a diameter similar to that of a fibre.