Fig. 6.

Mutant appearances from CAT2 [(a, b and c, 37 °C) and (d, e and f, 30 °C)]. An overnight culture of CAT2 (1×10⁹ c.f.u. ml⁻¹) was inoculated onto solid agar plates (0.5 % tryptone, 0.5 % NaCl and 1.5 % agar) (a and d), into liquid medium (0 % agar) (b and e) and into soft agar plates (0.3 % agar) (c and f). The solid agar and soft agar plates were incubated at 37 °C (a and c, repectively) or 30 °C (d and f, respectively) as specified, while the liquid media were incubated with rotation (250 r.p.m.) at 37 °C (b) or 30 °C (e). The total populations (diamonds) and the emerging insertion mutant populations (squares) were determined in LB and LB+Cm media, respectively. Error for triplicate determinations was within 10 % of the measured values.