Fish viscera protein hydrolysates: Production, potential applications and functional and bioactive properties.

Aptamer-Based Biosensors for Antibiotic Detection: A Review.

Aptasensors as the future of antibiotics test kits-a case study of the aptamer application in the chloramphenicol detection

Marine-derived antioxidant polysaccharides have aroused extensive attention because of their potential nutritional and therapeutic benefits. However, the comprehensive comparison of identified marine-derived antioxidant polysaccharides is still inaccessible, which would facilitate the discovery of more efficient antioxidants from marine organisms. Thus, this review summarizes the sources, chemical composition, structural characteristics, and antioxidant capacity of marine antioxidant polysaccharides, as well as their protective in vivo effects mediated by antioxidative stress reported in the last few years (2013–2019), and especially highlights the dominant role of marine algae as antioxidant polysaccharide source. In addition, the relationships between the chemical composition and structural characteristics of marine antioxidant polysaccharides with their antioxidant capacity were also discussed. The antioxidant activity was found to be determined by multiple factors, including molecular weight, monosaccharide composition, sulfate position and its degree.

https://www.mdpi.com/1660-3397/17/12/674/pdf

The Antioxidant Activity of Polysaccharides Derived from Marine Organisms: An Overview.

Antioxidant and anti-freezing peptides from salmon collagen hydrolysate prepared by bacterial extracellular protease.

Marine organisms are rich sources of structurally diverse bioactive nitrogenous components. In recent years, numerous bioactive peptides have been identified in a range of marine protein resources, such as antioxidant peptides. Many studies have approved that marine antioxidant peptides have a positive effect on human health and the food industry. Antioxidant activity of peptides can be attributed to free radicals scavenging, inhibition of lipid peroxidation, and metal ion chelating. Moreover, it has also been verified that peptide structure and its amino acid sequence can mainly affect its antioxidant properties. The aim of this review is to summarize kinds of antioxidant peptides from various marine resources. Additionally, the relationship between structure and antioxidant activities of peptides is discussed in this paper. Finally, current technologies used in the preparation, purification, and evaluation of marine-derived antioxidant peptides are also reviewed.

Overview of Antioxidant Peptides Derived from Marine Resources: The Sources, Characteristic, Purification, and Evaluation Methods.

An aptamer-based effective method for highly sensitive detection of chloramphenicol residues in animal-sourced food using real-time fluorescent quantitative PCR

Developing non-noble catalysts with superior activity and durability for oxygen evolution reaction (OER) in acidic media is paramount for hydrogen production from water. Still, challenges remain due to the inadequate activity and stability of the OER catalyst. Here, we report a cost-effective and stable manganese oxybromide (Mn7.5O10Br3) catalyst exhibiting an excellent OER activity in acidic electrolytes, with an overpotential of as low as 295 ± 5 mV at a current density of 10 mA cm-2. Mn7.5O10Br3 maintains good stability under operating conditions for at least 500 h. In situ Raman spectroscopy, X ray absorption near edge spectroscopy, and density functional theory calculations confirm that a self-oxidized surface with enhanced electronic transmission capacity forms on Mn7.5O10Br3 and is responsible for both the high catalytic activity and long-term stability during catalysis. The development of Mn7.5O10Br3 as an OER catalyst provides crucial insights into the design of non-noble metal electrocatalysts for water oxidation. 

/pdf/efficient-and-stable-noble-metal-free-catalyst-for-acidic-1ocsh18i.pdf

Efficient and stable noble-metal-free catalyst for acidic water oxidation

Chloramphenicol (CAP) has been widely used to treat bacterial infections in livestock and aquatic animals. To reduce the risk of CAP residues, an efficient technology to rapidly detect CAP residues in animal-sourced food is expressly needed. In this study, magnetic bead-based systematic evolution of ligands by exponential enrichment (Mag-SELEX) strategy was performed to select and identify CAP-specific single-stranded DNA (ssDNA) aptamers from a random oligonucleotide library. After nine rounds of selection, five potential ssDNA aptamers were selected. Low homology indicated that they might belong to different families. To identify an aptamer with the highest affinity for CAP, the dissociation constant (K d) values of these selected aptamers were determined. The lowest K d values of two potential aptamers (i.e., No. 4 and No. 5) were, respectively, 0.10162 ± 0.0111 and 0.03224 ± 0.00819 μM, which were much lower than previously reported lowest K d value (i.e., 0.766 μM) of CAP aptamer. Moreover, compared with No. 4, aptamer No. 5 had higher binding rate, which is quite different among those with CAP and with CAP's structural analogs (i.e., thiamphenicol (TAP) and florfenicol (FF)). These results indicated that the potential aptamer No. 5 with highest specificity and affinity for CAP would be an ideal aptamer for future detection of residual CAP in animal-sourced food.

Selection and Identification of Chloramphenicol-Specific DNA Aptamers by Mag-SELEX

Zymography is a widely used technique for the study of proteolytic activities on the basis of protein substrate degradation. In this study, substrate immersing zymography was used in analyzing proteolysis of extracellular proteases. Instead of being added directly into a sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gel, the substrates were added into the immersing solution after electrophoresis. Substrate immersing zymography could accurately determine the molecular weight of trypsin, and band intensities were linearly related to the amount of protease. The diversity of extracellular proteases produced by different marine bacteria was analyzed by substrate immersing zymography, and large variations of proteolysis were evidenced. The proteolytic activity of Pseudoalteromonas strains was more complicated than that of other strains. Five Pseudoalteromonas strains and five Vibrio strains were further analyzed by substrate immersing zymography with different substrates (casein and gelatin), and multiple caseinolytic and gelatinolytic profiles were detected. The extracellular proteolytic profiles of Pseudoalteromonas strains exhibited a large intraspecific variation. Molecular weight (Mw) of the main protease secreted by Vibrio was 35 kDa. Additionally, the time-related change trends of the activities of extracellular proteases produced by Pseudoalteromonas sp. SJN2 were analyzed by substrate immersing zymography. These results implied the potential application of substrate immersing zymography for the analysis of the diversity of bacterial extracellular proteases.

Hao Li

Papers

Overview of Antioxidant Peptides Derived from Marine Resources: The Sources, Characteristic, Purification, and Evaluation Methods.

An aptamer-based effective method for highly sensitive detection of chloramphenicol residues in animal-sourced food using real-time fluorescent quantitative PCR

Efficient and stable noble-metal-free catalyst for acidic water oxidation

Selection and Identification of Chloramphenicol-Specific DNA Aptamers by Mag-SELEX

In situ demonstration and characteristic analysis of the protease components from marine bacteria using substrate immersing zymography.