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Overload of hepatic palmitate, like palmitic acid (PA), is known as the key trigger for non-alcoholic fatty liver disease. Here, we investigated whether Chinese propolis (CP) would mitigate PA-induced lipotoxicity in hepatocytes. Total of 20 phenolic compounds were analysed in CP using HPLC-DAD/Q-TOF-MS. PA has significant cytotoxic effects on HepG2 and L02 hepatocytes, by decreasing cell viability and inducing LDH releases, which was rescued by CP pre-treatment. Lipoapoptosis was also found in HepG2 hepatocytes treated with PA and CP helped restore the energy provision and prevented cell apoptosis. After PA challenges, antioxidant effects of CP were also observed by boosting the HepG2 cellular total-antioxidant potentials, increasing superoxide dismutase level and up-regulating antioxidant/detoxicant gene expressions ( GSTA1 , TXNRD1 , NQO-1 , HO-1 and Nrf2 ). Notably, gene expressions of inflammatory cytokine, TNF-α and IL-8, were decreased by CP. Therefore, CP protects hepatocytes against PA-induced lipotoxicity by lowering biomarkers of apoptosis, oxidative stress and inflammation. [ABSTRACT FROM AUTHOR]

Honeybees (Apis mellifera) are important economic insects and play important roles in pollination and maintenance of ecological balance. However, the use of pesticides has posed a substantial threat to bees in recent years, with the more widely used deltamethrin being the most harmful. In this study, we found that deltamethrin exposure significantly reduced bee survival in a dose-dependent manner (p = 0.025). In addition, metagenomic sequencing further revealed that DM exposure significantly reduced the diversity of the bee gut microbiota (Chao1, p < 0.0001; Shannon, p < 0.0001; Simpson, p < 0.0001) and decreased the relative abundance of core species of the gut microbiota. Importantly, in studies of GF-bees, we found that the colonization of important gut bacteria such as Gilliamella apicola and Lactobacillus kunkeei significantly increased bee resistance to DM (survival rate increased from 16.7 to 66.7%). Interestingly, we found that the immunity-genes Defensin-2 and Toll were significantly upregulated in bees after the colonization of gut bacteria. These results suggest that gut bacteria may protect against DM stress by improving host immunity. Our findings provide an important rationale for protecting honeybees from pollutants from the perspective of gut microbes. [Display omitted] • Deltamethrin exposure disrupts the core gut microbiota of bees. • Colonization of G. Apis and L. Kunkeei significantly improved bee survival. • Kunkeei promotes the expression of immune genes against DM. [ABSTRACT FROM AUTHOR]

The mechanism of ionic wind and electric field of electrohydrodynamic (EHD) drying dehydration stress on the biochemical and molecular basis of bee pollen is still unclear. In this study, metabolomics and proteomics were employed to analyze the changes in biochemicals and small-molecule metabolic compounds of bee pollen during the drying process using needle-to-plate and plate-to-plate electrode system. The results show that ionic wind and electric field contributed 85.0% and 15.0% respectively to the dehydration characteristics, with the electric field having a greater effect on the quality parameters. As compared to ionic wind, the ribosome, the citric acid cycle (TCA cycle), and proteasome pathway played a positive role in regulating the abiotic and biochemical responses of electric field dehydration. Both ionic wind and electric field changed the expression of functional proteins related to amino acid metabolism pathways, resulting in a decrease in the expression of characteristic metabolites such as L-phenylalanine, L-aspartic acid, and L-pyroglutamic acid from 114.27 × 107, 5.31 × 107, and 142.55 × 107 in fresh rape bee pollen to 57.46 × 107, 3.32 × 107, and 57.46 × 107 in needle-to-plate (N-P) electrode treated and 61.25 × 107, 2.47 × 107, as well as 33.82 × 107 in plate-to-plate (P-P) electrode treated samples. Additionally, the differential expression of proteasome pathway and the destruction of the structural integrity of the cell wall storing phenolic compounds resulted in the further interaction of protein-phenolic supercomplexes, which in turn changed the content of free phenolic acids in rape bee pollen. These findings elucidated the biochemical regulation strategy and protein-phenolic compound interaction mechanism of rape bee pollen during EHD drying processing, and further emphasized the synergistic mechanism of ionic wind and electric field. [Display omitted] • Separate the respective roles of electric field and ionic wind. • Ionic wind has a greater influence on the drying characteristic parameters. • Electric field has significant effect on pathways related to protein denaturation. • Electrohydrodynamic drying affected the protein-phenolic acid interactions. • Combined metabolomics and proteomics study on the phytochemicals formation. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the antibacterial characteristics and antibacterial mechanisms of ɛ-poly-lysine against Escherichia coli and Staphylococcus aureus. The diameters of inhibition zones of E. coli (10 ± 0.5 mm) and S. aureus (12 ± 0.1 mm) treated by 200 μg/ml ɛ-poly-lysine were much larger than control (5 ± 0.3 mm) (p < 0.05). Minimum inhibition concentration of ɛ-poly-lysine against E. coli and S. aureus was 12.5 μg/ml. Scanning electron microscopy showed that ɛ-poly-lysine damaged the morphology of tested bacterial cells. The increase in electric conductivity of bacterial cells suspension indicated that the cytoplasmic membranes were broken by ɛ-poly-lysine, which caused leakage of ions in cells. SDS-PAGE of bacterial proteins demonstrated that ɛ-poly-lysine could damage bacterial cells through the destruction of cellular proteins. These results indicated that ɛ-poly-lysine has good potential to be as a natural food preservative. [ABSTRACT FROM AUTHOR]