Chunying Meng’s research while affiliated with Zhejiang Gongshang University and other places

The mussel Mytilus coruscus is an important and very popular seafood in China and widespread along the eastern coast of China. In this study, we investigated the molecular response of mussel gonads to cadmium accumulation at two concentrations (80 and 200 µg/L) for 30 days using ionomics and proteomics techniques. The shrinkage of the cells and moderate hemocytic infiltration were observed in the Cd-treated groups. The strontium, selenium (Se), and zinc contents were significantly altered, and the relationships between iron, copper, Se, manganese, calcium, sodium, and magnesium were also significantly altered. Label-free quantitative proteomics analysis revealed a total of 227 differentially expressed proteins. These proteins were associated with multiple biological processes, including the tricarboxylic acid cycle, structural reorganization of cells, biosynthesis of amino acids, inflammatory response of cells, and tumorigenesis. Nonetheless, our ionomics and proteomics analysis revealed that mussels could partly alleviate the adverse effects of Cd by altering the metal contents and correlations between minerals, thereby enhancing the biosynthesis of some amino acids and activity of antioxidant enzymes. Overall, this study provides an insight into the mechanism underlying Cd toxicity in mussel gonads from a metal and protein perspective.

The mussel Mytilus coruscus is an important and very popular seafood in China and widespread along the eastern coast of China. In this study, we investigated the molecular response of mussel gonads to cadmium hyperaccumulation at two concentrations (80 and 200 µg/L) for 30 days using ionomics and proteomics techniques. The shrinkage of the cells and moderate hemocytic infiltration were observed in the Cd-treated groups. The strontium, selenium (Se), and zinc contents were significantly altered, and the relationships between iron, copper, Se, manganese, calcium, sodium, and magnesium were also significantly altered. Label-free quantitative proteomics analysis revealed a total of 227 differentially expressed proteins. These proteins were associated with multiple biological processes, including the tricarboxylic acid cycle, structural reorganization of cells, biosynthesis of amino acids, inflammatory response of cells and tumorigenesis. Nonetheless, our ionomics and proteomics analysis revealed that mussels could partly alleviate the adverse effects of Cd by altering the metal contents and correlations between minerals, thereby enhancing the biosynthesis of some amino acids and activity of antioxidant enzymes. Overall, this study provides insight into the mechanism underlying Cd toxicity in mussel gonads from a metal and protein perspective.

Zn-binding protein was obtained after purification from scallops (Mizuhopecten yessoensis) using gel permeation and ion-exchange chromatography. Amino acid determination result shows that the cysteine of the zinc-binding protein accounts for one third of the total amino acids, which is a typical feature of metallothionein (MT). The secondary structure of zinc-binding protein was determined by Fourier Transform Infrared Spectroscopy (FTIR) and Circular dichroism (CD), the result shows that the α-helix was 46.55%, the β-sheets was 27.07%, the random coil was 16.48% and the β-turns was 9.89%. Using a commercial kit to measure its in vitro antioxidant activity, the result shows that it has good scavenging ability to 1, 1-diphenyl-2-picrylhydrazyl (DPPH), Hydroxyl radical (•OH) and reducing ability to ferrous iron ions. In this study, the extraction and purification of zinc-binding protein can be prepared in large quantities, which provide a basis for its industrialization.

Metal accumulation in the marine environment can increase the metal content of fish living in it. For this reason, it is essential to evaluate the nutrition from fish consumption and assess metal toxicity risk. Ten species of demersal fish, which are part of the daily diet of coastal residents, were sampled using trammel net in the East China Sea. Levels of the microelements, the constant elements, and the toxic elements of muscle tissue were analyzed. Spiny red gurnard had the highest concentrations of calcium, copper, and iron, whereas pufferfish and threadfin porgy were good sources of zinc and magnesium. The levels of lead, cadmium, and inorganic arsenic in all samples were below the limit values according to Chinese national standards. Although some concerns were raised about the concentration of mercury (Hg) in threadfin porgy, silver croaker, and fivespot flounder, molar ratios (selenium, Se:Hg) and the Se health benefit values (HBVSe) indicated that they were safe for human consumption. Additionally, the estimated weekly intake and % weekly contribution of 10 fish species with different elements were provided, giving a reference for the people’s healthy consumption.

Zn‐binding protein was obtained after purification from scallops (Mizuhopecten yessoensis) using gel permeation and ion‐exchange chromatography. Amino acid determination showed that the cysteine of the zinc‐binding protein accounted for one‐third of the total amino acids, which is a typical feature of metallothionein (MT). The spectra of Fourier Transform Infrared Spectroscopy (FTIR) and Circular Dichroism (CD) were analyzed to predict the secondary structure information of zinc‐binding protein: the α‐helix was 46.55%, the β‐sheets was 27.07%, the random coil was 16.48%, and the β‐turns was 9.89%. Using a commercial kit to measure its antioxidant activity in vitro, the result showed that it had good scavenging ability to 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH), hydroxyl radical (·OH), and reducing the ability to ferrous iron ions. With the process provided by this study, zinc‐binding protein can be prepared in large quantities, which is the basis for its future commercialization. Practical applications According to the extraction and purification process established in this study, a large amount of zinc‐bound MT from the viscera of scallops can be obtained. And the zinc‐bound MT had good antioxidant activity. In addition, the yield of each purification step has been calculated. The zinc‐bound MTs from scallop’ viscera can be prepared in large quantities by directly using the process in this manuscript or by equal magnification of this process. In the future, large‐scale production can be considered to increase the economic value of scallops’ viscera.

Zinc-binding proteins named MT-M-I and MT-M-II were obtained after purification from metal-exposed hairy clams (Arca subcrenata) using gel permeation and ion-exchange chromatography. MT-M-I and MT-M-II were resolved by ion-exchange chromatography, and they were found to have similar molecular weights. MT-M-I and MT-M-II can bind 6 and 7 equivalents of Zn²⁺ in vitro, and they showed unusual migration behaviors in Tricine sodium dodecyl sulfate polyacrylamide gel electrophoresis (Tricine-SDS-PAGE). Such migration behaviors may be due to themetal thiolate clusters in these proteins. In terms of amino acid composition, the proportion of cysteine in MT-M-I and MT-M-II was approximately 30%, and glycine accounted for approximately 15%, where as aromatic amino acids were absent. Considering the performance in Tricine-SDS-PAGE and the amino acid compositions, MT-M-I and MT-M-II conform to the molecular characteristics of the metallothionein proteins. The structures were explored using circular dichroism (CD) and Fourier-transform infrared spectroscopy (FTIR). Also determined the antioxidant activities in terms of DPPH radical scavenging ability, hydroxyl radical (·OH) scavenging ability, and ferric-reducing/antioxidant power. The antioxidant activities of MT-M-I were found to be stronger than those of MT-M-II.