Antagonistic Effect of Selenium on Fumonisin B1 Promotes Neutrophil Extracellular Traps Formation in Chicken Neutrophils.

Neutrophils are an important component of the innate immune system, and one of their defense mechanisms, neutrophil extracellular traps (NETs), is a hot topic of the current research. This study explored the effects of fumonisin B1 (FB1) on chicken neutrophil production of NETs and its possible molecular mechanism of action. Scanning electron microscopy and fluorescence microscopy were used to observe morphological changes in neutrophils, and a fluorescence microplate reader was used to detect reactive oxygen species (ROS) and extracellular DNA release from neutrophils. Quantitative PCR (qPCR) and western blot were used to determine the expression levels of selenoproteins. The results indicate that FB1 inhibited the zymosan-induced formation of NETs in chicken neutrophils by preventing ROS burst and histone H3 (H3) and neutrophil elastase (NE) release. Moreover, the mRNA expression levels of glutathione peroxidase (GPX), thioredoxin reductase (TXNRD), and deiodinase (DIO) were downregulated in the FB1 group. The protein expression levels of GPX1, GPX2, GPX3, DIO3, and TXNRD1 were consistent with the changes in their gene expressions, suggesting an abnormal selenoprotein expression in response to the toxic effects of FB1. Conversely, selenium (Se) supplementation reduced the toxic effects of FB1 and restored the NETs formation, indicating that Se can be used as a potential drug to prevent and control FB1 toxicity in livestock farming.

Removal of Copper (II) by Biochar Mediated by Dissolved Organic Matter.

The effects of humic acid (HA) and fulvic acid (FA) on Cu2+ adsorption on biochar were investigated, with mechanisms confirmed by excitation-emission matrix spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy. HA loading enhanced Cu2+ adsorption on biochar, with the maximum enhancement of 55.0% occurring at an HA loading of 100 mg-C/L. The adsorbed HA introduced many additional functional groups to biochar, thus enhancing Cu2+ adsorption, which decreased at HA concentrations >100 mg-C/L due to self-association of HA at high loading concentrations. In contrast, FA loading caused no enhancement on Cu2+ adsorption on biochar. FA was adsorbed through H-bonding with the functional groups of biochar, which set up a competition with Cu2+ for adsorption on biochar. The functional groups occupied by adsorbed FA were offset by the newly introduced functional groups of FA, thus there was no net increase in the amount of Cu2+ adsorption upon FA loading. These findings imply that, because of the enhanced adsorption of HA-loaded biochar, the amount of Cu2+ immobilized would increase by 28.2% for mature compost and 31.9% for fresh compost if there exist interaction between biochar and HA compared with the amounts immobilized by non-interactive HA and biochar.