Fig. 7. Heat shock protein accumulation in isolated shark lateral choroid plexus (CP) after zinc exposure with KNK437 in absence of trimethylamine oxide (TMAO). Lateral CPs from an individual shark were divided, yielding four equal-sized segments; each segment was incubated at 13.5°C in TMAO-free L15E medium. Tissues were incubated without zinc ± 100 µmol l^–1 KNK437 or with 50 µmol l^–1 ZnSO₄ ± 100 µmol l^–1 KNK437 for 6 h; all tissues were then incubated for 1.5 h in zinc-free medium containing TMAO ± 100 µmol l^–1 KNK437. For tissues not treated with KNK437, medium contained 0.2% DMSO (vehicle). (A) Representative immunoblot analysis of Hsp70 and actin accumulation in lysates of lateral CP treated in the absence of TMAO without zinc or with zinc ± KNK437. (B) Graphical comparison of Hsp70 induction by zinc exposure ± KNK437 in the absence of TMAO (mean ± s.e.m.; N=3). Fold-induction of Hsp70 was calculated by dividing Hsp70 accumulation (normalized to actin) in zinc-treated tissue without or with KNK437 by the normalized Hsp70 accumulation in timed-control tissue incubated without KNK437. ^*P<0.05 vs fold-induction in control and ^**P<0.05 vs fold-induction in zinc only, respectively.