RESUMO
This study concerns the relationship between spontaneous revertants and number of bacterial cells plated in the Ames test. These two parameters do not appear to bear a direct relationship: marked variations in cell input are attended by negligible variations in spontaneous revertants. However, a relationship, described by a quadratic equation that approximates a hyperbole, exists between the spontaneous revertants and the number of total cellular divisions permitted by the histidine concentration in the medium. Furthermore a direct linear relationship has been observed between cell input and diameter of the plate background microcolonies. The problem of the toxic effect in the Ames test performed with drugs or substances having high bactericidal activity is discussed.
