Molecular characterization of two superoxide dismutases from Hydra vulgaris

Abstract

Apparent full-length cDNA sequences coding for manganese superoxide dismutase (HvMnSOD) and extracellular superoxide dismutase (HvEC-SOD) were isolated from Hydra vulgaris in order to understand their expression and 3D structures; and explore their possibility of being used as for biomarkers for environmental stress and toxicity. The deduced HvMnSOD protein consists of 219 amino acids of which first 21 amino acids constitute a presumed mitochondria-targeting signal peptide whereas HvEC-SOD protein consists of 189 amino acids of which first 19 amino acids constitute a presumed signal peptide. Molecular model generated for HvMnSOD displayed the N-terminal long alpha antiparallel hairpin and the C-terminal mixed alpha/beta fold characteristic of MnSODs and that for HvEC-SOD displayed the characteristic CuZnSOD â-barrel fold. Hydrae subjected to thermal, starvation, metal and oxidative stress responded by regulating MnSOD and EC-SOD mRNA transcription. These results indicated that these genes are involved in the cellular stress response and (anti)oxidative processes triggered by stressor and contaminant exposure. Hence the expression of these SODs in hydra may have potential as molecular biomarkers for assessing stress, toxicity and pro-oxidant quality of chemicals and aquatic environmental quality.

Activation of the cnidarian oxidative stress response by ultraviolet light, polycyclic aromatic hydrocarbons and crude oil

“…Phylogenetic analysis of the N. vectensis SOD genes provides a glimpse into the diversification of SODs early in the evolution of animals and within the cnidarian lineage. Two CuZnSODs have previously been identified in the anemone A. viridis (Plantivaux et al, 2004), one in the hydrozoan H. vulgaris (Dash et al, 2007) and eight from an initial search of the genome of the coral A. digitifera (Shinzato et al, 2012). We have identified three CuZnSODs in N. vectensis, two of which are orthologs of the genes from A. viridis.…”

“…At the sequence level, searches of genomic and expressed sequence tag (EST) databases of the sea anemones Nematostella vectensis (Goldstone, 2008;Reitzel et al, 2008b) and Aiptasia pallida (Sunagawa et al, 2009), the coral Acropora digitifera (Shinzato et al, 2012) and the hydrozoan Hydra magnapapillata (Shinzato et al, 2012) have demonstrated the presence of multiple genes encoding antioxidant enzymes, including CuZnSODs, MnSODs, catalase, thioredoxins and glutathione peroxidases. Two CuZnSODs have been cloned from A. viridis (Plantivaux et al, 2004), and an extracellular CuZnSOD and a mitochondrial MnSOD have been identified in the freshwater hydrozoan Hydra vulgaris (Dash et al, 2007). Catalase has been cloned from A. viridis (Merle et al, 2007) and H. vulgaris (Dash and Phillips, 2012).…”

“…Exposure of Hydra to elevated temperatures or to a variety of metals induced expression of catalase and one or more SODs within 6 h (Dash et al, 2007;Dash and Phillips, 2012). SOD and catalase activity and/or expression can be induced in corals by elevated temperatures and ultraviolet (UV) radiation, and these levels have been used as stress biomarkers in corals (Barshis et al, 2013;Császár et al, 2009;Downs et al, 2000;Souter et al, 2011).…”

Hydra, a model system for environmental studies

“…On the other hand, Hydra have the capacity to protect against oxidative stress since they contain two superoxide dismutase (SOD) genes (Dash et al, 2007). The SOD are of the type MnSOD which are principally found in the mitochondria and of the type CuZnSOD which is cytosolic in cells.…”

Genomic Survey of Candidate Stress-Response Genes in the Estuarine AnemoneNematostella vectensis

“…Previous research with cnidarians, primarily anthozoans, has characterized the expression of SODs and catalase (CAT) in response to environmental stress (Richier et al, 2003(Richier et al, , 2005Yakovleva et al, 2004;Dash et al, 2006Dash et al, , 2007Merle et al, 2007).…”