FIG 4.

Rhodamine 6G efflux and inhibition by FK506. Plasmid gene expression was induced by overnight growth in galactose medium. Cells were preloaded with R-6G, and the efflux assay was then performed under either glucose-replete (+GLC) conditions (A) or glucose-starved (−GLC) conditions (B) or under glucose-replete conditions with 5 μM FK506 (+GLC +FK506) (C). Fluorescence accumulation in the medium over time was measured in RFU. High levels of fluorescence indicate strong R-6G efflux activity.