Validation of the C. elegans model using juglone as a positive control for oxidative stress

To confirm the suitability of C. elegans as a model organism, preliminary gene expression experiments were performed using juglone (5-hydroxy-1,4-naphthoquinone; 97% pure; Sigma-Aldrich, St-Louis, MO), an ROS-generator, as a positive control of oxidative stress (d'Arcy Doherty et al. 1987; Leiers et al. 2003). Reproduction tests were initially performed to establish the sub-lethal effect concentrations used in the microarray experiments. The effects of juglone on C. elegans gene expression were then measured after 24 h of exposure to 0.2, 2, and 20 μM juglone as compared to negative control (K-medium). Four replicates for each concentration and 12 replicates for negative controls were analyzed as single color microarray.