Two variants of selenium-dependent glutathione peroxidase from the disk abalone Haliotis discus discus: Molecular characterization and immune responses to bacterial and viral stresses. Issue 2 (August 2015)

• Record Type: Journal Article
• Authors: Bathige, S.D.N.K.; Umasuthan, Navaneethaiyer; Godahewa, G.I.; Thulasitha, William Shanthakumar; Whang, Ilson; Won, Seung Hwan; Kim, Chul; Lee, Jehee
• Is Part Of: Fish & shellfish immunology. Volume 45:Issue 2(2015:Aug.)
• Page Start: 648
• Page End: 655
• Publication Date: 2015-08
• Subjects: Selenium-dependent glutathione peroxidase (SeGPx) -- Haliotis discus discus -- Immune response -- AbSeGPx-a -- AbSeGPx-b; Fishes -- Immunology -- Periodicals; Shellfish -- Immunology -- Periodicals; Poissons -- Immunologie -- Périodiques; Crustacés -- Immunologie -- Périodiques; 571.9617
• DOI: 10.1016/j.fsi.2015.05.028
• Languages: English
• ISSNs: 1050-4648

Abstract

Abstract: Glutathione peroxidase (GPx) is an essential member of the antioxidant systems of living organisms and may be involved in immune defense against pathogenic invasion. In the current study, two selenium-dependent glutathione peroxidases ( AbSeGPx s) that shared 54.3% identity were identified from the disk abalone Haliotis discus discus . The open reading frames (ORFs) of AbSeGPx-a and AbSeGPx-b coded for 222 and 220 amino acids, respectively, with a characteristic selenocysteine residue encoded by an opal stop codon (TGA). The conserved selenocysteine insertion sequence (SECIS) element was predicted in the 3′ untranslated region (UTR) of both isoforms, and they were found to form two stem-loop structures. Amino acid comparison and phylogenetic studies revealed that the AbSeGPxs were closely related to those in other mollusk species and were evolutionarily distinct from those of other taxonomic groups. The SYBR Green qPCR was employed in investigating the transcripts of AbSeGPx s. The expression of AbSeGPx s mRNA was examined in different embryonic developmental stages and differential expression patterns for AbSeGPx-a and AbSeGPx-b were noted. Meanwhile, the highest expression of AbSeGPx s was detected in the hepatopancreas of healthy adult animals. Next, transcriptional levels were profiled in hemocytes of adults to determine the immune responses of AbSeGPx s to microbial infections. The results revealed the significant up-regulation of AbSeGPx-a in a time-dependent manner after bacterial ( Listeria monocytogenes and Vibrio parahaemolyticus ) and viral (viral hemorrhagic septicemia virus) infections. Consequently, these findings indicate that AbSeGPx-a and AbSeGPx-b might be involved in the embryonic development of disk abalone and the regulation of immune defense system of adult animals. Highlights: Two full length cDNA sequences of SeGPxs ( AbSeGPx ) were characterized from disk abalone. The SECIS element was predicted at the 3′ UTR of both AbSeGPx s and found to form stem loop structure. Significant expression of AbSeGPxs transcripts were detected during early developmental stages. Significantly up-regulated transcription of AbSeGPx s after live bacterial and viral infections was observed.