Figure 2

Exposure of PE255 worms to the respiratory inhibitor sodium azide (NaN ₃ ) for 30 min. A. Luminescence (in vivo) and fluorescence as a % of controls not exposed to NaN₃. Luminescence decreased markedly with increasing concentration of NaN₃, whereas survival remained 100% throughout (not shown). Fluorescence intensity tracked the GFP module of LUC+::GFP and was indicative of expression levels of the fused protein. It remained fairly constant throughout, except for 15 mM NaN₃ where a small decrease was observed. The drop in luminescence was consistent with decreased ATP levels caused by NaN₃. Synchronised L4 larval stage worms (from 45 h post hatch liquid cultures) were used. Error bars show the SEM. The pooled number of worms was 1200 (± 81) per tested condition. B. As a result of not feeding, a nematode treated with 1 mM azide for 30 min does not show red fluorescing microspheres in its pharynx. C. Red microspheres accumulate in the pharynx of control nematodes exposed to 0 mM azide. D. Luciferase activity (measured by in vitro luminescence) in lysates of worms exposed to NaN₃, expressed as % of control values and normalised to protein content. There were no significant changes in luciferase activity with increasing NaN₃ concentrations (Regression not significant; P = 0.623466), so that luciferase activity did not influence final in vivo luminescence. Error bars show the standard error of the mean (SEM). The pooled number of worms was 4000 (± 169) per tested condition.