A new UiO-66-NH2 MOF-based nano-immobilized DFR enzyme as a biocatalyst for the synthesis of anthocyanidins.

Anthocyanidins and anthocyanins are one subclass of flavonoids in plants with diverse biological functions and have health-promoting effects. Dihydroflavonol 4-reductase (DFR) is one of the important enzymes involved in the biosynthesis of anthocyanidins and other flavonoids. Here, a new MOF-based nano-immobilized DFR enzyme acting as a nano-biocatalyst for the production of anthocyanidins in vitro was designed. We prepared UiO-66-NH2 MOF nano-carrier and recombinant DFR enzyme from genetic engineering. DFR@UiO-66-NH2 nano-immobilized enzyme was constructed based on covalent bonding under the optimum immobilization conditions of the enzyme/carrier ratio of 250 mg/g, 37 °C, pH 6.5 and fixation time of 10 min. DFR@UiO-66-NH2 was characterized and its catalytic function for the synthesis of anthocyanidins in vitro was testified using UPLC-QQQ-MS analysis. Compared with free DFR enzyme, the enzymatic reaction catalyzed by DFR@UiO-66-NH2 was more easily for manipulation in a wide range of reaction temperatures and pH values. DFR@UiO-66-NH2 had better thermal stability, enhanced adaptability, longer-term storage, outstanding tolerances to the influences of several organic reagents and Zn2+, Cu2+ and Fe2+ ions, and relatively good reusability. This work developed a new MOF-based nano-immobilized biocatalyst that had a good prospect of application in the green synthesis of anthocyanins in the future.

MIZ1 acts downstream of PGM1 in regulating root hydrotropism.

The MIZ1 play an important role in root hydrotropism. However, the relationship between MIZ1-regulated hydrotropism and amyloplast-mediated gravitropism remain largely unclear. Here, we generated the miz1/pgm1 double mutants by crossing the non-hydrotropic miz1 mutant with the amyloplast-defective pgm1 mutant, which lacks gravitropic response. Our results showed that the miz1/pgm1 mutants exhibited a significant reduction in amyloplast and gravitropic bending, while maintaining a similar ahydrotropic phenotype as the miz1 single mutant. These findings suggest that MIZ1 plays a role in hydrotropism downstream of PGM1. Understanding the mechanisms of interaction between hydrotropism and gravitropism is crucial for comprehending the rooting patterns of plants in natural conditions. The counteracting relationship between root hydrotropism and gravitropism in the miz1 mutant should receive attention in this field, particularly considering the interference from gravitropism on Earth.

[Effect of guarana on lipid metabolism in obese rats: a study based on lipidomics].

This study investigated the effect of guarana on plasma lipid metabolites in obese rats and analyzed its mechanism in the treatment of dyslipidemia in obesity. High-fat diet was used to establish obese rat models, and the therapeutic effect of guarana on obese rats was evaluated by measuring body weight, white fat, liver weight, and lipid content, as well as observing liver histomorphology. Lipid metabolites in plasma of rats in each group were detected by UHPLC-Q-TOF-MS lipidomics. The protein expressions of fatty acid synthase, acetyl-CoA carboxylase 1, triglyceride synthesis enzyme, carnitine palmitoyltransferase Ⅰ, and acetyl-coenzyme A acyltransferase 2 in rat liver were detected using Western blot. The results revealed that guarana significantly reduced body weight, white fat, and liver weight of obese rats due to high-fat diet, and alleviated dyslipidemia and liver steatosis. Lipidomics showed that some triglycerides and phospholipids were significantly elevated in the high-fat model group, and part of them was reduced after guarana treatment. Western blot found that guarana inhibited the expression of hepatic fatty acid and triglyceride synthesis-related proteins and increased the expression of fatty acid ß-oxidation-related proteins. Abnormalities in triglyceride and phospholipid metabolism are the main characteristics of plasma lipid metabolism in obese rats induced by high-fat diet. Guarana may regulate partial triglyceride and phospholipid metabolism by inhibiting hepatic fatty acid and triglyceride synthesis and increasing fatty acid ß-oxidation, thereby improving rat obesity and dyslipidemia.

[Study on time-toxicity relationship and mechanism of Gardeniae Fructus extract on hepatoxicity in rats based on proteomics].

To study the time-toxicity relationship and mechanism of Gardeniae Fructus extract on the hepatoxicity in rats. Rats were randomly divided into C group(0 day), D5 group(5 days), D12 group(12 days), D19 group(19 days), and D26 group(7 days recovery after 19 days of administration). The rats in normal group received normal saline through intragastric administration, and the rats in other groups received 10 g·kg~(-1 )Gardeniae Fructus extract through intragastric administration. After the final administration, the livers were collected. Hematoxylin-eosin staining was used to observe the histopathological changes in the liver tissue. Total liver proteins were extracted for proteomic analysis, detected by the Nano-ESI liquid-mass spectrometry system and identified by Protein Disco-very software. SIEVE software was used for relative quantitative and qualitative analysis of proteins. The protein-protein interaction network was constructed based on STRING. Cytoscape software was used for cluster analysis of differential proteins. Kyoto encyclopedia of genes and genomes(KEGG) database was used to perform enrichment signal pathway analysis. Pearson correlation analysis was performed for the screened differential protein expression and liver pathology degree score. The results showed that the severity of liver injury in D5, D12 and D19 groups was significantly higher than that in group C. The degree of liver damage in D5 group was slightly higher than that in D12 and D19 groups, with no significant difference between group D26 and group C. Totally 147 key differential proteins have been screened out by proteomics and mainly formed 6 clusters, involving in drug metabolism pathways, retinol metabolism pathways, proteasomes, amino acid biosynthesis pathways, and glycolysis/gluconeogenesis pathways. The results of Pearson correlation analysis indicated that differential protein expressions had a certain temporal relationship with the change of liver pathological degree. The above results indicated that the severity of liver damage caused by Gardeniae Fructus extract did not increase with time and would recover after drug with drawal. The above pathways may be related to the mechanism of liver injury induced by Gardeniae Fructus extract.