Proteome and Transcriptome Analysis of the Antioxidant Mechanism in Chicken Regulated by Eucalyptus Leaf Polyphenols Extract.

Eucalyptus leaf polyphenols extract (EPE) has been proved to have various bioactivities, but few reports focus on its antioxidant mechanism in vivo. The purpose of this study was to elucidate the effect and mechanism of EPE dietary supplements on antioxidant capacity in chicken. A total of 216 chickens were randomly selected for a 40-day experiment. Four treatment groups received diets including the control diet only, the control diet + low EPE (0.6 g/kg), the control diet + moderate EPE (0.9 g/kg), and the control diet + high EPE (1.2 g/kg). Compared with control group, the glutathione peroxidase (GSH-Px) activity and glutathione (GSH) content in the breast muscle of the moderate EPE treatment group was significantly higher (p < 0.05), while the malonaldehyde (MDA) content in the moderate EPE group was reduced (p < 0.05). Moreover, proteomic and transcriptomic analyses of the breast muscle revealed that glutathione metabolism and the peroxisome were the two crucial metabolic pathways responsible for increased antioxidant capacity of the muscle. Accordingly, nine candidate genes and two candidate proteins were identified related to improved antioxidant status induced by EPE supplements. This research provides new insights into the molecular mechanism of antioxidant capacity in chickens treated with EPE dietary supplements.

A novel process for obtaining pinosylvin using combinatorial bioengineering in Escherichia coli.

Pinosylvin as a bioactive stilbene is of great interest for food supplements and pharmaceuticals development. In comparison to conventional extraction of pinosylvin from plant sources, biosynthesis engineering of microbial cell factories is a sustainable and flexible alternative method. Current synthetic strategies often require expensive phenylpropanoic precursor and inducer, which are not available for large-scale fermentation process. In this study, three bioengineering strategies were described to the development of a simple and economical process for pinosylvin biosynthesis in Escherichia coli. Firstly, we evaluated different construct environments to give a highly efficient constitutive system for enzymes of pinosylvin pathway expression: 4-coumarate: coenzyme A ligase (4CL) and stilbene synthase (STS). Secondly, malonyl coenzyme A (malonyl-CoA) is a key precursor of pinosylvin bioproduction and at low level in E. coli cell. Thus clustered regularly interspaced short palindromic repeats interference (CRISPRi) was explored to inactivate malonyl-CoA consumption pathway to increase its availability. The resulting pinosylvin content in engineered E. coli was obtained a 1.9-fold increase depending on the repression of fabD (encoding malonyl-CoA-ACP transacylase) gene. Eventually, a phenylalanine over-producing E. coli consisting phenylalanine ammonia lyase was introduced to produce the precursor of pinosylvin, trans-cinnamic acid, the crude extraction of cultural medium was used as supplementation for pinosylvin bioproduction. Using these combinatorial processes, 47.49 mg/L pinosylvin was produced from glycerol.