Scanning electron and light microscopy of selected avian strains of Mycoplasma iowae.

The morphology of six strains of Mycoplasma iowae was studied at various stages of growth by scanning electron and light microscopy. The six strains, which formerly represented avian mycoplasmal serotypes I, J, K, N, Q, and R, produced filaments and branching filaments, sometimes with centrally or terminally located bulbous swellings. During cell division, the filaments appeared to develop into chains of coccal, coccobacillary, and elongated cells. Mycoplasmas that appeared as chains of cocci under light microscopy were often observed as coccobacillary or fusiform when viewed with scanning electron microscopy. The morphology of single or paired cells of all strains included cocci, rods, coccobacilli, and pleomorphic forms. Fusiform and teardrop-shaped cells with bleb-like structures were also observed. Some cells of all strains deteriorated by the latter growth stages, forming clumps of flattened irregular-shaped cells, sometimes intertwined with fragmented filaments. The formation of filaments, branching filaments, and the other cell morphology indicated that the six strains of M. iowae were similar in morphology and growth characteristics.