FIG. 2.

Schematic representation of the results of a Δlcb3 synthetic-lethality screen. A Δlcb3 screening strain constructed for the purpose of the synthetic-lethality screen forms red colonies when it contains the LCB3 plasmid and white colonies when it lacks the plasmid. Under nonselective growth conditions, this strain undergoes frequent plasmid loss, resulting in formation of sectored red and white colonies. Mutations that give advantage to cells that retain the plasmid will result in solid-red colonies.