Viability in fertile stocks of Pseudomonas aeruginosa.

Diluent composition, time consumed in experimental manipulations, and the presence of pyocine-like lethal agents affected the viability of sexual fertility factor-positive and fertility factor-negative auxotrophic stocks of Pseudomonas aeruginosa. In the same cultures, recovery of prototrophic revertants increased as the number of viable cells dispensed per plate was reduced. As a result, the number of revertants recovered was indirectly determined by the combined activities of the three conditions affecting viability. Possible modifications by these conditions affecting viability on the expression and interpretation of the fertility factor-positive sex factor-mediated system of genetic recombination are presented.