Wu Q.,Jimei University |
Fu X.-P.,Jimei University |
Fu X.-P.,Chinese Academy of Fishery Sciences |
Sun L.-C.,Jimei University |
And 7 more authors.
International Journal of Food Science and Technology | Year: 2015
R-phycoerythrin (R-PE) was purified from the red algae Bangia fusco-purpurea after 35-50% ammonium sulphate fractionation followed by ion-exchange column chromatography on DEAE-Sepharose, resulting in a purity (A565/A280) ratio of 5.1. The circular dichroism spectroscopy results suggested that the structure of R-PE is predominately helical. The antioxidant activity of R-PE was studied and revealed changes in conformation and antioxidant activity at different temperatures and pH values. After in vitro-simulated gastrointestinal (GI) digestion of R-PE, the scavenging activity of ABTS radical (EC50, 769.9 μg mL-1), DPPH radical (EC50, 421.9 μg mL-1), hydroxyl radical (EC50, 32.4 μg mL-1) and reducing power (A700 = 0.5, 625.8 μg mL-1) were measured. Gel filtration chromatography analysis showed that the molecular weight distribution of the final GI digest that still contained high antioxidant activity was <3 kDa. Our present results indicate that digestion-resistant antioxidant peptides of R-PE may be obtained by in vitro GI proteinases degradation. © 2015 Institute of Food Science and Technology.
Shi B.,Xiamen University |
Xiang X.,Xiamen University |
Ke Y.,Xiamen University |
Zhou L.,Xiamen University |
And 2 more authors.
Comparative Biochemistry and Physiology Part - B: Biochemistry and Molecular Biology | Year: 2015
Oysters are considered hyper-accumulators of Cu, but the molecular mechanism by which they maintain Cu cell homeostasis is still unclear. ATP-binding cassette protein subfamily B member 1 (ABCB1, P-glycoprotein) can transport a variety of substrates across the cell membrane in aquatic animals. In this study, to provide insight into the roles of ABCB1 in resistance against Cu in oysters, complete cDNA of abcb1 gene in Crassostrea angulata was cloned and analyzed. The complete sequence of C. angulata ABCB1 showed high identity to ABCB1 from other bivalves and contained some classical motifs of ABCB transport proteins. Abcb1 was mainly expressed in the apical epithelial cell of gills and epithelia of mantles. Abcb1 expression and Cu accumulation were also studied in control oysters and oysters exposed to Cu (30, 100, 300. μg/L Cu, 1-15. days). Cu accumulation in the gill and mantle were measured after abcb1 gene interference. The complete sequence of C. angulata ABCB1 showed high identity to ABCB1 from other bivalves and contained some classical motifs of ABCB transport proteins. The mRNA transcript of abcb1 showed hypersensitivity to Cu exposure. A concentration-dependent highest abcb1 mRNA level (up to 5.61-fold to the control) in the gill and mantle existed across all Cu exposure concentrations after 3. days of Cu exposure. The gill and mantle Cu concentration were significantly higher after the abcb1 mRNA interference. According to these results, it is here speculated that ABCB1 may underlie cell protection against Cu in C. angulata. © 2015.