Selenocysteine

Five L4/young adult worms were transferred to a fresh NGM plate and permitted to lay eggs for 5 h. After removing the five adult worms, the progeny were grown on NGM plates for 3 days. Age-synchronized worms were treated with different concentrations (0, 1, 2.5, or 5 mM) of selenocysteine (Sigma-Aldrich, St. Louis, USA) for 24 h. The worms were then exposed to 1 or 2 mM H₂O₂ in S-basal without cholesterol (5.85 g sodium chloride, 1 g potassium phosphate dibasic, and 6 g potassium phosphate monobasic for 1 L sterilized distilled water). The survival of worms under oxidative-stress conditions was monitored after 6 h. Worms not responding to any mechanical stimuli were considered dead. Three independent replicate experiments were performed. Statistical significance was measured using the standard two-tailed Student’s t-test. P-values less than 0.05 were considered significant.

The substances FURA 2-AM (FURA-2-pentakis (acetoxymethyl) ester, Triton X-100 (t-octylphenoxypolyethoxyethanol), EGTA (ethylene glycol-bis (β-aminoethyl ether)-N,N,N’,N’-tetracetic acid), sodium selenite (Na₂SeO₃), sodium selenate (Na₂SeO₄), selenomethionine (SeMet), selenocysteine (SeCys), Se-(methyl)selenocysteine (Se SeMeSeCys), and protease (Protease TypeXIV), as well as olive pollen, were purchased from the Sigma-Aldrich corporation (St. Louis, MO, USA), along with nitric acid (HNO₃ 65% RPE), dimethyl sulfoxide (DMSO), hydrogen peroxide (H₂O₂ 40% wv RE pure), and other reagents (reagent grade).