FIG 1.

Zinc acquisition and efflux in GAS. (A) Diagram representation of the gene locations of adcR, adcC, adcB, adcA, and adcAII in the GAS 5448 genome. Gene sizes are to scale. (B, C) Comparison of the relative levels of expression of zinc export (czcD) and zinc import (adcA, adcB, and adcAII) genes in strain 5448 wild type under zinc excess (1 mM ZnSO₄) (B) or zinc-limiting (65 μM TPEN) (C) conditions. Error bars show standard deviations of the results from 3 independent experiments. The relative levels of gene expression were calculated using the cycle threshold (2^−ΔΔCT) method, with gyrA as the reference gene, and are expressed as fold changes in expression in GAS grown under zinc overload or -limiting conditions compared to the expression in GAS grown in THY alone. Two-way ANOVA was used to compare the relative levels of gene expression under zinc excess or zinc-limiting conditions to their expression in THY (P < 0.0001). (D to F) Comparison of the growth of 5448 WT and isogenic deletion mutants (ΔczcD, ΔadcA, ΔadcAII, ΔadcA ΔadcAII, and ΔadcBC) in Todd Hewitt broth plus 1% yeast extract (THY) (D) and THY supplemented with 1 mM zinc sulfate (E) or 65 μM TPEN (F). Graph is representative of 3 independent experiments.