Transcriptional up-regulation of disk abalone selenium dependent glutathione peroxidase by H2O2 oxidative stress and Vibrio alginolyticus bacterial infection

Transcriptional regulation of selenium-dependent glutathione peroxidase from Venerupis philippinarum in response to pathogen and contaminants challenge

“…Significance across control was indicated with an asterisk at P < 0.05. hepatopancreas. Similar tissue expression profiles were also found in H. discus discus, U. tumidus and C. farreri GPx transcripts [2,13,14], perhaps due to the fact that hepatopancreatic lysosomes were the sites for generation of ROS [31]. Moreover, VpSe-GPx mRNA was found moderately expressed in haemocytes which were known to be responsible for respiratory burst and killing foreign invaders in bivalve mollusks [32,33].…”

“…BLAST homology analysis yielded close matches of VpSe-GPx with many other Se-GPxs in mollusks. VpSe-GPx contained a 279 TGA 281 codon corresponding to Sec (U 75 ) residue [17], SECIS region indispensable for selenocysteine incorporation [30], two Se-GPx signature motifs and functional residues (Q 109 , W 182 ), suggesting that VpSe-GPx was a selenium-dependent protein and possessed similar antioxidant functions with other Se-GPx [2,9]. By the phylogenetic analysis with extensive numbers of GPx isozymes, the invertebrate GPx protein family was scattered without forming a clearly defined invertebrate GPx cluster.…”

“…The role of GPx in the host immune defense system and antioxidant defense system has been well documented in invertebrates including mollusks [13,14] and arthropods [4,15]. Presently, six isoforms of the GPx family have been discovered in mammals [2,16], which are classified into two subgroups as selenium-dependent glutathione peroxidase (Se-GPx) and non-selenium glutathione peroxidase (non-Se-GPx), based on the presence of Sec encoded by a stop codon (TGA) at their active sites [17]. The difference between these two types of enzymes is that Se-GPx catalyzes the reduction of both organic and inorganic peroxides, while non-Se-GPx act only on organic peroxides [15].…”

“…Recently, several studies have demonstrated the immune modulation of GPx in marine invertebrates such as GPx of Haliotis discus discus [2], Chlamys farreri [14], Litopenaeus vannamei [4], Fenneropenaeus chinensis [15]. GPx has also been well characterized for its antioxidant activity in Unio tumidus [13] and Crassostrea gigas [21].…”

Cloning and expression of selenoprotein W from pearl mussels Cristaria plicata

“…Usually, the mRNA transcripts of selenoprotein possessing an antioxidant function are up-regulated after bacteria and virus infection. Litopenaeus vannamei SelM expression was transiently induced in gills after infection with the white spot syndrome virus (WSSV) on a time dependent manner (Clavero-Salas et al, 2007), the expression of selenoprotein glutathione peroxidase mRNA was significantly and could be induced by pathogen challenge (De Zoysa et al, 2008;Yeh et al, 2009;Liu et al, 2010). It was suggested that SelW was an antioxidant protein for lipid peroxidation (Jeong et al, 2002;Whanger, 2009).…”