Fig. 2. (A) Inhibition of rainbow trout gill basolateral membrane vesicle (BLMV) Ag(I) transport at 50 µmol l^-1 AgNO₃ by 500 µmol l^-1 of non-radioactive Ag(I), Cu(II), Pb(II), Cd(II), Zn(II) and Fe(III). Values are means ± S.E.M., numbers indicate N values. Asterisks indicate significant differences from control values (Student t-test performed on arcsine transformed data, P<0.05). (B) Concentration-dependent Ag(I) transport (solid circles), and in the presence of 800 µmol l^-1 Cu(II) (open circles). Values are means ± S.E.M., N=6, taken from two separate experiments. Both sets of data best-fitted a sigmoidal curve with regression equations: for the control vesicle Ag(I) transport, y=3.5±2.1/(1+e^{-(x-15.1±3/17.5±2.4)}), r²=0.992; for Ag(I) transport in Cu(II)-treated vesicles, y=9.8±1.6/(1+e^{-(x-17.4±2.9/6.4±3.5)}), r²=0.993. The Cu(II)-treated vesicle Ag(I) transport is significantly reduced (two-way analysis of variance, P=0.0052). The protocol for BLMV preparation and transport buffer media were taken from Bury et al. (1999).