Bacillus clausii Enhances Oxidative Stress Resistance in C. elegans

Caenorhabditis elegans strains N2, Bristol (wild type) was obtained from the Caenorhabditis Genetics Center at the University of Minnesota and maintained at 20 °C on Nematode Growth Medium (NGM) plates with E. coli strain OP50 as normal diet for nematodes. Overnight, B. clausii CSI08 culture was grown, as described in Section 2.1, and then centrifuged for 10 min at 4000× g. Supernatants were then removed, and bacterial pellets were washed once with saline solution. C. elegans wild-type strain (N2) cultured in NGM (control fed condition), or NGM supplemented with B. clausii CSI08 at two different doses (10⁸ and 10⁹ cells/plate). Vitamin C (10 µg/mL) was used as positive control. Worms were incubated in these conditions and after several days were submitted to an acute oxidative stress (2 mM H₂O₂) according to a previously published protocol [46 (link)]. Afterwards, viability of nematodes was determined in each fed condition. Experiments were performed in duplicate. Each experiment was conducted on 5 different plates, each containing 10 worms (50 worms/assay). The antioxidant activity (worm survival) of total population was calculated. Final survival data correspond to the average of two independent assays (total population of 100 worms/condition). The effect of B. clausii CSI08 antioxidant activity was studied by comparing the survival of treated nematodes versus the control-fed nematodes.