Metabolic consequences of mycoplasmal contamination of cell cultures

KB cells originally derived from epitheloid carcinoma of the nasopharynx were found to be contaminated with mycoplasma. The contaminated cells showed significantly higher glycolytic (EMP) and respiratory (TCA) rates when compared with non-contaminated or 'cured' cells. The activity of the hexose monophosphate (HMP) shunt, an alternative pathway of glucose metabolism, was shown to be reasonably higher than normal KB cell levels. Treatment involving combination of heat (41 degrees C) and kanamycin (350 microgram/cm3) for 21 hours was found to adequately and selectively inactivate the mycoplasmal population. Following cure, the metabolism of the cells fell well within normal ranges. The treatment showed no deleterious effects on the KB cell population. The possibility and the significance of an independent hexose monophosphate shunt activity in the mycoplasma population in addition to the already established partial TCA and EMP activities, and the overall significance of detection of carbohydrate metabolism in these organisms, are discussed.