ABSTRACT
To overcome the spread of the severe COVID-19 outbreak, various lockdown measures have been taken worldwide. China imposed the strictest home-quarantine measures during the COVID-19 outbreak in the year 2020. This provides a valuable opportunity to study the impact of anthropogenic emission reductions on air quality. Based on the GEE platform and satellite imagery, this study analyzed the changes in the concentrations of NO2, O3, CO, and SO2 in the same season (1 February-1 May) before and after the epidemic control (2019-2021) for 16 typical representative cities of China. The results showed that NO2 concentrations significantly decreased by around 20-24% for different types of metropolises, whereas O3 increased for most of the studied metropolises, including approximately 7% in megacities and other major cities. Additionally, the concentrations of CO and SO2 showed no statistically significant changes during the study intervals. The study also indicated strong variations in air pollutants among different geographic regions. In addition to the methods in this study, it is essential to include the differences in meteorological impact factors in the study to identify future references for air pollution reduction measures.
Subject(s)
Air Pollutants , Air Pollution , COVID-19 , Humans , Air Pollutants/analysis , COVID-19/epidemiology , Nitrogen Dioxide/analysis , Search Engine , Environmental Monitoring/methods , Communicable Disease Control , Air Pollution/analysis , Cities , China/epidemiology , Particulate Matter/analysisABSTRACT
The balance of oxidation and reduction in the body requires the synergistic effect of various antioxidant enzymes. Therefore, the construction of enzyme mimics with multiple antioxidant activities is important and beneficial for further research on the synergistic effects of antioxidant enzymes and their mechanism of action. To explore the synergistic effect of superoxide dismutase (SOD) and glutathione peroxidase (GPx), a 76-mer selenium-containing peptide (Se-76P) mimic containing the active SOD and GPx centers was designed. Moreover, a cell-penetrating peptide was introduced into Se-76P by structure modeling, and then, Se-76P was expressed by a single-protein production combined with the cysteine auxotrophic double-expression system of Escherichia coli. The results suggest that Se-76P exhibits SOD and GPx activities, following the GPx activity of 109 U/mg protein and the SOD activity of 1218 U/mg protein. The labeled Se-76P with FITC fluorescence was verified to enter the L02 cells successfully; it improved the antioxidant activity in cells and promoted the consumption of glucose and synthesis of glycogen. The injection of Se-76P subcutaneously decreased the levels of blood glucose and malondialdehyde of lipid peroxidation produced in mice, indicating that Se-76P had antioxidative properties and a certain regulatory role of glucose metabolism. The data analysis provides further clarification that Se-76P can regulate insulin signal transduction to play an insulin-like role, which not only has a greater significance for further elucidating the catalytic mechanism of the enzyme and their synergistic effects on each other but also has enormous medicinal potential.
Subject(s)
Cell-Penetrating Peptides/chemistry , Insulin/metabolism , Lipid Peroxidation/drug effects , Peptides/chemistry , Antioxidants/chemistry , Antioxidants/metabolism , Carbohydrate Metabolism/genetics , Catalytic Domain/drug effects , Cell-Penetrating Peptides/pharmacology , Glucose/metabolism , Glutathione Peroxidase/chemistry , Humans , Insulin/chemistry , Oxidation-Reduction/drug effects , Peptides/genetics , Peptides/pharmacology , Selenium/chemistry , Superoxide Dismutase/chemistryABSTRACT
Increasing evidence indicates that microRNAs(miRNAs) are often aberrantly expressed in osteosarcoma (OS) and play critical roles in OS tumorigenesis. Therefore, the discovery of miRNAs may provide a new and powerful tool for understanding the mechanismof OS initiation and development. The aim of this study was to investigate the functional significance of miR-365 and identify its possible mechanism in OS cells. Here, wefound that the expression level of miR-365 is significantly downregulated in OS tissues and cell lines, and its expression isassociated with the clinical stage, distant metastasis, tumor grade, and poor overall survival rate. The overexpression of miR-365 is able to inhibit cell proliferation, migration, and invasion in Saos-2 and MG-63 cells. Moreover, the cysteine-rich angiogenic inducer 61 (CYR61) has been identified as a target of miR-365 in OS cells, and its expression is found to be significantly increased in OS tissues, which is negatively correlated with miR-365. Furthermore, CYR61 overexpression significantly attenuated the suppressive effects of miR-365 on the proliferation, migration, and invasion of Saos-2 and MG-63 cells. Therefore, we consider that miR-365 acts as a tumor suppressor in OS, partly, by targeting CYR61 expression.
