A Thermophilic, Acidophilic Mycoplasma Isolated from a Coal Refuse Pile

Abstract

A thermophilic, acidophilic procaryote lacking a cell wall has been isolated from a coal refuse pile which had undergone self-heating. Electron micrographs, chemical assays for hexosamine, and the inability of vancomycin to inhibit growth confirm the lack of a cell wall. The apparent ability of the organism to reproduce by budding and the low guanine plus cytosine content of its DNA indicate a relation to the mycoplasmas. The temperature optimum of the organism is 59°C, and growth occurs over a range of 45° to 62°C. No growth occurs at 37°C or at 65°C. The optimum p H for growth is between 1 and 2, and growth occurs between p H 0.96 and 3.5 but does not occur at p H 0.35 and only poorly at p H 4.0. We propose to call this organism Thermoplasma acidophila . The existence of this organism extends considerably the range of habitats in which mycoplasma may occur.