Influence of Urea on the Growth of T-Strain Mycoplasmas

Abstract

T-strain mycoplasmas require urea for propagation, but urea metabolism also occurs in nonpropagating viable cultures. Ammonia results from this metabolism and alkalinizes the medium. Ammonium ions and an alkaline p H both inhibit the multiplication of T strains and reduce the viability of T strains in broth. These toxic effects of urea metabolism currently limit the growth of T strains in broth. Stock T-strain cultures are optimally maintained in continuous culture if the routine medium at p H 6.0 is supplemented with 0.05% urea and 0.002% phenol red, but an incubation temperature of 30 C is preferable to 37 C for subculture at 24-hr intervals.