Journal of Agricultural and Food Chemistry最新文献

Naringenin (4,5,7-trihydroxyflavone, NAR) is an effective active ingredient in Rhizoma Drynariae, which has many biological functions, encompassing anti-inflammatory and -oxidant functions. Prior research has shown that NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasomes possessed a significant contribution to osteoporosis. However, the NAR impact on bone loss caused by microgravity remains unclear. Classical microgravity simulation methods were used to induce simulated microgravity (SMG) in mice and cells. Microcomputed tomography, immunohistochemical examination, and hematoxylin and eosin staining were implemented to ascertain alterations in bone microstructure and morphology in mice subsequent to NAR gavage. Cellular investigations were implemented encompassing quantitative real-time polymerase chain reaction, Western blotting, and immunofluorescence labeling to investigate the molecular mechanism behind NAR resistance to microgravity-induced bone loss. Our research has shown that NAR can significantly enhance the SMG-stimulated alterations in bone microstructure and morphology in mice, mainly by increasing the trabecular thickness, bone volume fraction, and trabecular number while increasing the bone trabecula number. Cell experiments also showed that SMG caused the activation of inflammatory corpuscles of NLRP3 and induced pyroptosis simultaneously, which can be confirmed by the upregulation of protein and mRNA expression levels such as those of NLRP3, cleaved caspase-1, gasdermin D, and apoptosis-associated speck-like protein. The occurrence of pyroptosis further led to the disorder of osteogenic differentiation, which showed that the osteopontin, Runt-related transcription factor 2, bone morphogenetic protein 2, and alkaline phosphatase expression levels were decreased. The intervention of NAR can activate the nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) pathway, reverse this phenomenon via controlling the reactive oxygen species generation in cells and correcting mitochondrial malfunction, weaken the pyroptosis of osteoblasts (OBs), and promote osteogenic differentiation. In summary, NAR could hinder the pyroptosis of OBs caused by SMG and promote osteogenic differentiation via activating the Nrf2/HO-1 pathway. This provides a unique view for inhibiting bone loss under weightlessness and confirms the NAR capacity in treating microgravity-stimulated bone loss, giving new ideas and methods for future space medicine development.

Phytoene, a colorless carotenoid with unique ultraviolet (UV)-B absorption properties, offers potential for applications in functional food, cosmetics, and therapeutics. However, their low natural yield poses a challenge for large-scale production. This study aims to enhance phytoene production in the oleaginous yeast Yarrowia lipolytica by introducing a heterologous phytoene synthase gene combined with metabolic engineering approaches. We enhanced phytoene synthesis by overexpressing key genes in the mevalonate pathway and compartmentalizing the biosynthetic pathway within peroxisomes. Moreover, we inhibited the glyoxylate cycle to increase the accumulation of peroxisomal acetyl-CoA available for phytoene production. Our engineered strains demonstrated a significant increase in phytoene production, reaching up to 1.34 g/L titer and 58.74 mg/gDCW yield in the flask-scale fed-batch culture, which are the highest levels reported to date. These results underscore the potential of Y. lipolytica as a robust platform for producing phytoenes and other terpenoids on an industrial scale, offering valuable insights for future efforts in metabolic engineering.

In this study, the nuarimol enantiomers were successfully baseline separated with Rs 1.70 by ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The absolute configurations of the nuarimol enantiomers were confirmed as R-(+)-nuarimol and S-(-)-nuarimol. The enantioselective bioactivity assay indicated that R-(+)-nuarimol exhibited greater potency against seven phytopathogenic fungi, with values approximately 1.4-3.5 and 4.5-51.4 times higher than those of rac-nuarimol and S-(-)-nuarimol. The active contribution value of R-enantiomer was 82-98%, showing that R-(+)-nuarimol played a crucial role in bioactivity. Meanwhile, R-(+)-nuarimol exhibited stronger effects in increasing the cell membrane permeability, compromising the cell membrane integrity, and inhibiting ergosterol biosynthesis. Molecular docking analysis showed that R-(+)-nuarimol possessed a stronger binding affinity to sterol 14-α demethylase (CYP51) than S-(-)-nuarimol, with docking energies of -7.42 and -7.36 kcal/mol. This study contributes essential data for screening a high-activity enantiomer of nuarimol and provide guidance for reducing used dosage and increasing the efficiency of nuarimolAQ.

Mitigating the cold denaturation of gluten protein during frozen storage is crucial for the quality improvement of frozen cereal products. Our previous study observed that starch derivatives, especially short-clustered maltodextrin (SCMD), could significantly improve frozen dough quality, alleviating the deterioration of gluten-network structure. To further reveal the cryoprotection mechanism of SCMD on gluten protein during frozen storage, the modulatory roles of SCMD in the hydration capacity and conformation behavior of gluten protein were explored, in comparison with DE2 maltodextrin (MD) and pregelatinized starch (PGS). Results demonstrated that SCMD significantly facilitated the reservation of bound water and decreased the surface hydrophobicity of gluten protein after 8 weeks of frozen storage. Remarkable effects of SCMD on stabilizing the secondary structure and microenvironment of aromatic amino acids of gluten protein were observed. Further mechanistic investigation showed that when the temperature dropped from 300 to 250 K, the short-clustered structure could stabilize the α-helixes more evidently than linear structures through hydrogen bonds with water and steric hindrance effect, rather than directly with protein. Our findings will provide novel insights into the cold denaturation of gluten protein and useful guidance in selecting the optimum structure to suppress this denaturation, improving the quality of frozen cereal products.

Building upon previous structure-activity relationships about the fungicidal amide and hydrazide lead structures, 24 novel amide-hydrazide compounds were designed and synthesized with L-isoleucine as the initial skeleton to explore the impact of substituents in the hydrazide bridge on the fungicidal activity. Among these compounds, A5 exhibited excellent and broad spectrum inhibitory activity, along with satisfactory in vivo protective efficiency against R. solani at concentrations of 200 and 50 μg·mL^-1. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations revealed that compound A5 induced significant morphological changes in the R. solani mycelium coupled with vacuole rupture and cytoplasmic inhomogeneity in cellular structures. Transcriptomic and metabolomic analyses indicated that, following A5 treatment, the differentially expressed genes and metabolites were significantly enriched in carbohydrate metabolism-related pathways as well as in lipid metabolism-associated pathways, including glycerophospholipid metabolism, steroid biosynthesis, arachidonic acid metabolism, and sphingolipid metabolism. Additionally, compound A5 demonstrated low toxicity to zebrafish, with survival rates of 100% and 60% at concentrations of 1 and 10 μg·mL^-1, respectively, over a period of 7 days. The above results provide theoretical guidance for the development of novel green hydrazide fungicidal candidates.