Molecular Characterization of Mn-superoxide Dismutase and Gene Expression Studies in Dietary Restricted Brachionus plicatilis Rotifers

Superoxide dismutases (SODs) promote a conversion of harmful reactive oxygen species (ROS) to relatively moderate forms, resulting in the extension of lifespan in the nematode Caenorhabditis elegans under caloric restriction. The lifespan of the rotifer Brachionus plicatilis is also markedly extended by caloric restriction. We, therefore, cloned cDNA encoding SOD activated with Mn (Mn SOD) from B. plicatilis and examined its expression pattern in rotifers raised with energy restricted diet. The full length deduced amino acid sequence of the rotifer Mn SOD showed 61% identity with the C. elegans ortholog. Four amino acid residues that are essential to the binding of this enzyme to Mn were conserved in the rotifer Mn SOD. Subsequently we examined the mRNA expression patterns of Mn SOD using highly sensitive quantitative real-time PCR for various rotifer populations that are likely to differ in their lifespans in experiments on calorie restricted diets. The accumulated mRNA levels of Mn SOD were found to increase in supposedly long-lived rotifers. These results suggest that Mn SOD is possibly related to the aging of B. plicatilis.