Nutritional Effects on the Growth, Cell Size, and Resistance to Stress of Acholeplasma laidlawii.

Due to their lack of a cell wall, mycoplasmas are useful models for the study of biological membranes. However, they are much less appreciated by cell culture laboratories due to their unfortunate tendency to contaminate cell culture lines (1-5). One of the primary protections of a cell line is through filtration of cell culture media. It is necessary to use 0.1 μm-rated filters because mycoplasmas can often penetrate the more commonly used 0.2 (or 0.22) μm-rated filters. In the battle against mycoplasma contamination, it is helpful to delineate factors that may affect mycoplasma replication, cell size, and resistance to contamination control. The addition of cholesterol and unsaturated long chain fatty acids to growth media enhance replication of Acholeplasma laidlawii (6-10). The absence of glucose, presence of unsaturated fatty acids, increased incubation period, and exposure to stress promote the production of small mycoplasma cells (6-12). Exposure to a high salt concentration, hydrogen peroxide, and UV light, which are commonly used for contamination control, can enhance the production of small resistant cells (13-15).