FIG. 6.

lac complementation and growth analysis of transformants. The pEXSs derivative vectors pEXlacS and pEXlacOP were transferred into the mutant GθW cells by electroporation, and transformants were selected on gelrite plates containing only lactose as a nutrient. (A) The LacS⁻ GθW did not produce any colonies when plated onto lactose medium (negative control; plate a), and lacS transformants failed to grow, maintaining the lactose metabolic defect (plate b), whereas transformation with the construct containing both lacS and lacTr restored the wild-type phenotype and sustained growth on minimal medium (plate c). (B) Growth of four independent transformants was monitored in both rich tryptone-lactose (Trp-Lac) and minimal lactose (Lac) media and resulted in nearly identical overlapping curves (solid squares) compared to cultures of the wild-type Gθ (•) and untransformed GθW (▵) strains under the same conditions. OD₆₀₀, optical density at 600 nm.