Enigmatic Mycoplasma Colonies: Analysis by Scanning and Transmission Electronic Microscopy

The aim of this work is to study the morphology and ultrastructural organization of four mycoplasma species of Mollicutes class forming microcolonies (MCs) of an unknown early morphotype. The investigation was carried by scanning and transmission electronic microscopy. It was discovered that mycoplasma populations are heterogeneous at first. MCs of all species differ radically from typical classical colonies (CCs). MCs have a spiral form with a dense center and blades composed of rod-shaped cells. Colonies are arranged in almost parallel rows of cells arranged closely side by side. The ultrastructure of MC cells is unusual. Cells of different species have a longitudinal fissure on the cell surface, which dilates at one end or splits up in the form of a hand. CCs and MCs of different mycoplasma species have the same organization. Issues of the origin of these forms and their role in the species conservation are discussed. Our work showed that populations of mycoplasma cells are heterogeneous. The morphology and ultrastructural organization of MCs and their cells are unique, which was shown for the first time by scanning and transmission microscopy.