Fig. 2. Viability of G. dibranchiata erythrocytes exposed to H₂S in vitro. (A–E) Epifluorescence micrographs of cells exposed to control conditions (A) or H₂S at 0.10% (B), 0.32% (C), 1.0% (D) and 3.2% (E) for 2 h, followed by labeling with calcein (green) and propidium iodide (PI; red). Scale bar=100 µm. (F) Quantitative analysis of calcein and PI labeling following H₂S exposure. `Calcein' (green circles) represents cells with cytoplasmic calcein labeling; `NPI' (red triangles) represents cells with nuclear PI labeling; `Total PI' (red circles) represents cells with nuclear or cytoplasmic PI labeling. Asterisks indicate a significant difference from control conditions by one-way analysis of variance (ANOVA) with Dunnett's post-hoc test, N=3.