Fig. 3.
H2S memory is long-lived. (A) Scheme showing the experimental setup used to test the durability of sulfide exposure. (B) Representative OCR traces for cells ± 100 µM Na2S after 4, 24, and 48 h. While control cells rapidly oxidized 20 µM Na2S (red arrow), pretreated cells were inhibited up to 48 h. The black and red lines represent the OCR before and after recovery from 20 µM Na2S, respectively. (C) Changes in cellular P50(O2) values 4, 24, and 48 h after a single exposure to 100 µM Na2S. (D) Pretreatment with 100 µM Na2S results in lower H2S clearance and thiosulfate production 4 h later. (E–G) Sulfide (0 to 100 µM) pretreatment (4 or 24 h) resulted in a dose-dependent inhibition of OCR following Na2S reexposure (20 µM) (E), increased time to recovery of a new stationary OCR (F), but had no impact on the total O2 consumed during the recovery time (G). The average total O2 consumed per sulfide was estimated to be 1.5 ± 0.1 across all sulfide pretreatment concentrations. The two-sample unpaired t test was performed for statistical analysis (C–G).