A comprehensive review of Pt electrocatalysts for the oxygen reduction reaction: nanostructure, activity, mechanism and carbon support in PEM fuel cells

The sluggish rate of the oxygen reduction reaction (ORR) in proton exchange membrane (PEM) fuel cells has been a major challenge. Significantly increasing efforts have been made worldwide towards a highly active ORR catalyst with high durability. Among all the catalysts exploited, Pt electrocatalysts are still the best in terms of a comprehensive evaluation. The investigation of Pt-based ORR catalysts is necessary for a practical ORR catalyst with low Pt content. This paper reviews recent progress in the studies of the mechanism, nanostructure, size effect and carbon supports of Pt electrocatalysts for the ORR. The importance of the size and structure control of Pt ORR catalysts, related with carbon support materials, is indicated. The potential methods for such control are discussed. The progress in theoretical studies and in situ catalyst characterization are also discussed. Finally, challenges and future developments are addressed

Low beauvericin concentrations promote PC-12 cell survival under oxidative stress by regulating lipid metabolism and PI3K/AKT/mTOR signaling

Beauvericin (BEA), a naturally occurring cyclic peptide with good pharmacological activity, has been widely explored in anticancer research. Although BEA is toxic, studies have demonstrated its antioxidant activity. However, to date, the antioxidant mechanisms of BEA remain unclear. Herein, we conducted a comprehensive and detailed study of the antioxidant mechanism of BEA using an untargeted metabolomics approach, subsequently validating the results. BEA concentrations of 0.5 and 1 μM significantly inhibited H2O2-induced oxidative stress (OS), decreased reactive oxygen species levels in PC-12 cells, and restored the mitochondrial membrane potential. Untargeted metabolomics indicated that BEA was primarily involved in lipid-related metabolism, suggesting its role in resisting OS in PC-12 cells by participating in lipid metabolism. BEA combated OS damage by increasing phosphatidylcholine, phosphatidylethanolamine, and sphingolipid levels. In the current study, BEA upregulated proteins related to the PI3K/AKT/mTOR pathway, thereby promoting cell survival. These findings support the antioxidant activity of BEA at low concentrations, warranting further research into its pharmacological effects

Identification of a Novel Walnut Iron Chelating Peptide with Potential High Antioxidant Activity and Analysis of Its Possible Binding Sites

Peptide iron chelate is widely regarded as one of the best iron supplements for relieving iron deficiency. In this study, a new type of walnut peptide iron (WP-Fe) chelate was prepared using low molecular weight walnut peptides (WP) as raw materials. Under the conditions of this study, the chelation rate and iron content of the WP-Fe chelate were 71.87 ± 1.60% and 113.11 ± 2.52 mg/g, respectively. Fourier transform infrared spectroscopy (FTIR), zeta potential, amino acid composition, and other structural analysis showed that WP-Fe is formed by the combination of carboxyl, amino and carbonyl with Fe2+. The WP-Fe chelate exhibits a honeycomb-like bulk structure different from that of WP. In addition, we predicted and established the binding model of ferrous ion and WP by molecular docking technology. After chelation, the free radical scavenging ability of the WP-Fe chelate was significantly higher than that of the WP. Overall, the WP-Fe chelate has high iron-binding capacity and antioxidant activity. We believe that peptides from different sources also have better iron binding capacity, and peptide iron chelates are expected to become a promising source of iron supplement and antioxidant activities

Differential protein analysis of saline-alkali promoting the oil accumulation in Nitzschia palea

Abstract Background The increasingly severe salinization of the aquatic environment has led to serious damage to the habitats of aquatic organisms. Benthic diatoms are commonly employed as indicator species for assessing water quality and serve as a reflection of the overall health of the aquatic ecosystem. Nitzschia palea is a common diatom found in freshwater, with high oil content, rapid reproductive rate, and it is a commonly dominant species in various rivers. Results The results showed that after 4 days (d) of saline-alkali stress, the cell density and chlorophyll a content of Nitzschia palea reached their maximum values. Therefore, we selected Nitzschia palea under 4 d stress for Tandem Mass Tag (TMT) quantitative proteomic analysis to explore the molecular adaptation mechanism of freshwater diatoms under saline-alkali stress. Totally, 854 proteins were enriched, of which 439 differentially expressed proteins were identified. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and subcellular fractionation analysis revealed that these proteins were mainly enriched in the photosynthesis pathway, citric acid cycle (TCA cycle), fatty acid synthesis, and glutathione cycle. Conclusions This study aims to reveal the physiological, biochemical and proteomic mechanisms of salt and alkali tolerance and molecular adaptation of Nitzschia palea under different saline-alkali concentrations. This study showed that Nitzschia palea is one candidate of the environmental friendly, renewable bioenergy microalgae. Meantime, Nitzschia palea reveals for the proteome of the freshwater and provides the basis, it became a model algal species for freshwater diatoms

Molecular Mechanism of <i>MYL4</i> Regulation of Skeletal Muscle Development in Pigs

The processes of muscle growth and development, including myoblast proliferation, migration, differentiation, and fusion, are modified by a variety of regulatory factors. MYL4 plays an important role in atrial development, atrial cardiomyopathy, muscle-fiber size, and muscle development. The structural variation (SV) of MYL4 was found via the de novo sequencing of Ningxiang pigs, and the existence of SV was verified in the experiments. The genotype distribution of Ningxiang pigs and Large White pigs was detected, and it was found that Ningxiang pigs were mainly of the BB genotype and that Large White pigs were mainly of the AB genotype. However, the molecular mechanisms behind the MYL4-mediated regulation of skeletal muscle development need to be deeply explored. Therefore, RT-qPCR, 3′RACE, CCK8, EdU, Western blot, immunofluorescence, flow cytometry, and bioinformation analysis were used to explore the function of MYL4 in myoblast development. The cDNA of MYL4 was successfully cloned from Ningxiang pigs, and its physicochemical properties were predicted. The expression profiles in six tissues and four stages of Ningxiang pigs and Large White pigs were found to be the highest in the lungs and 30 days after birth. The expression of MYL4 increased gradually with the extension of the myogenic differentiation time. The myoblast function test showed that the overexpression of MYL4 inhibited proliferation and promoted apoptosis and differentiation. The knockdown of MYL4 showed the opposite result. These results enhance our understanding of the molecular mechanisms of muscle development and provide a solid theoretical foundation for further exploring the role of the MYL4 gene in muscle development

Circular Intronic RNA circTTN Inhibits Host Gene Transcription and Myogenesis by Recruiting PURB Proteins to form Heterotypic Complexes

Muscle cell growth plays an important role in skeletal muscle development. Circular RNAs (circRNAs) have been proven to be involved in the regulation of skeletal muscle growth and development. In this study, we explored the effect of circTTN on myoblast growth and its possible molecular mechanism. Using C2C12 cells as a functional model, the authenticity of circTTN was confirmed by RNase R digestion and Sanger sequencing. Previous functional studies have showed that the overexpression of circTTN inhibits myoblast proliferation and differentiation. Mechanistically, circTTN recruits the PURB protein on the Titin (TTN) promoter to inhibit the expression of the TTN gene. Moreover, PURB inhibits myoblast proliferation and differentiation, which is consistent with circTTN function. In summary, our results indicate that circTTN inhibits the transcription and myogenesis of the host gene TTN by recruiting PURB proteins to form heterotypic complexes. This work may act as a reference for further research on the role of circRNA in skeletal muscle growth and development