Uracil phosphoribosyl transferase activity of mycoplasma and infected cell cultures

Human H.Ep-2 and mouse 3T6 cells infected by Mycoplasma hyorhinis showed an increase in [3H]uracil uptake and a more than 20-fold increase in the activity of uracil phosphoribosyltransferase (UraPRT). Uninfected cell cultures gave background levels of this enzyme activity. A survey of 16 strains of mycoplasma showed 13 to possess UraPRT activity. Rabbit kidney cells (RK13) were infected with eight different strains of four mycoplasma species known to be common cell culture contaminants. Seven of the eight cell cultures showed elevated UraPRT activities four days after infection. This enzyme activity may be of value in monitoring cell cultures for mycoplasma and aid in classification.