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Journal of Industrial Microbiology &... Jan 2024As a key molecular scaffold for various flavonoids, naringenin is a value-added chemical with broad pharmaceutical applicability. For efficient production of naringenin...
UNLABELLED
As a key molecular scaffold for various flavonoids, naringenin is a value-added chemical with broad pharmaceutical applicability. For efficient production of naringenin from acetate, it is crucial to precisely regulate the carbon flux of the oxaloacetate-phosphoenolpyruvate (OAA-PEP) regulatory node through appropriate pckA expression control, as excessive overexpression of pckA can cause extensive loss of OAA and metabolic imbalance. However, considering the critical impact of pckA on naringenin biosynthesis, the conventional strategy of transcriptional regulation of gene expression is limited in its ability to cover the large and balanced solution space. To overcome this hurdle, in this study, pckA expression was fine-tuned at both the transcriptional and translational levels in a combinatorial expression library for the precise exploration of optimal naringenin production from acetate. Additionally, we identified the effects of regulating pckA expression by validating the correlation between phosphoenolpyruvate kinase (PCK) activity and naringenin production. As a result, the flux-optimized strain exhibited a 49.8-fold increase compared with the unoptimized strain, producing 122.12 mg/L of naringenin. Collectively, this study demonstrated the significance of transcriptional and translational flux rebalancing at the key regulatory node, proposing a pivotal metabolic engineering strategy for the biosynthesis of various flavonoids derived from naringenin using acetate.
ONE-SENTENCE SUMMARY
In this study, transcriptional and translational regulation of pckA expression at the crucial regulatory node was conducted to optimize naringenin biosynthesis using acetate in E. coli.
Topics: Escherichia coli; Phosphoenolpyruvate; Flavonoids; Acetates; Flavanones
PubMed: 38285614
DOI: 10.1093/jimb/kuae006 -
Foods (Basel, Switzerland) Nov 2023Malic acid is the predominant organic acid in grape berries, and its content is affected by abiotic factors such as temperature (fruit zone microclimate) and water (vine...
Malic acid is the predominant organic acid in grape berries, and its content is affected by abiotic factors such as temperature (fruit zone microclimate) and water (vine water status). The objectives of this study were to explore the potential mechanisms behind the effects of vine water status on the biosynthesis and degradation of berry malic acid and the potential downstream effects on berry metabolism. This study was conducted over two growing seasons in 2021 and 2022, comprising three watering regimes: no water stress (CK), light water stress (LWS), and moderate water stress (MWS). Compared to CK, a significantly higher level of malic acid was found in berries from the MWS treatment when the berry was still hard and green (E-L 33) in both years. However, water stress reduced the malic acid content at the ripe berry harvest (E-L 38) stage. The activities of NAD-malate dehydrogenase (NAD-MDH) and pyruvate kinase (PK) were enhanced by water stress. Except for the E-L 33 stage, the activity of phosphoenolpyruvate carboxylase (PEPC) was reduced by water stress. The highest phosphoenolpyruvate carboxykinase (PEPCK) activity was observed at the berry veraison (E-L 35) stage and coincided with the onset of a decrease in the malate content. Meanwhile, the expression of was consistent with its enzyme activity. This study showed that water stress changed the content of some free amino acids (GABA, proline, leucine, aspartate, and glutamate), two of which (glutamate and GABA) are primary metabolites of the GABA pathway.
PubMed: 38231685
DOI: 10.3390/foods12234191 -
ACS Omega Jan 2024Conjugated linoleic acid (CLA) holds significant application prospects due to its anticancer, anti-atherosclerosis, lipid-lowering, weight-loss, and growth-promoting...
Conjugated linoleic acid (CLA) holds significant application prospects due to its anticancer, anti-atherosclerosis, lipid-lowering, weight-loss, and growth-promoting functions. The key to its efficient production lies in optimizing the biocatalytic performance of linoleic acid isomerase (LAI). Here, we constructed a mutant library and screened positive mutants with high linoleate isomerase activity. The proteomics and metabolomics were used to explore the mechanism in the regulation of linoleic acid isomerase activity. High-throughput proteomics revealed 104 differentially expressed proteins unique to positive mutant strains of linoleic acid isomerase of which 57 were upregulated and 47 were downregulated. These differentially expressed proteins were primarily involved in galactose metabolism, the phosphotransferase system, starch metabolism, and sucrose metabolism. Differential metabolic pathways were mainly enriched in amino acid biosynthesis, including glutamate metabolism, the Aminoacyl-tRNA biosynthesis pathway, and the ABC transporter pathway. The upregulated metabolites include dl-valine and Acetyl coA, while the downregulated metabolites include Glutamic acid and Phosphoenolpyruvate. Overall, the activity of linoleic acid isomerase in the mutant strain was increased by the regulation of key proteins involved in galactose metabolism, sucrose metabolism, and the phosphotransferase system. This study provides a theoretical basis for the development of high-yield CLA food.
PubMed: 38222669
DOI: 10.1021/acsomega.3c08243 -
PloS One 2024We evaluated the effect of Tucum-do-Cerrado on glucose metabolism homeostasis and its relationship with redox-inflammatory responses in a high-fat (HF) diet-induced...
INTRODUCTION
We evaluated the effect of Tucum-do-Cerrado on glucose metabolism homeostasis and its relationship with redox-inflammatory responses in a high-fat (HF) diet-induced obesity model.
RESULTS
The HF diet increased energy intake, feed efficiency, body weight, muscle and hepatic glycogen, insulin, homeostatic model assessment of insulin resistance (HOMA IR) and beta (β)-cell function, and gut catalase (CAT) activity, and decreased food intake, hepatic glutathione reductase (GR), glutathione peroxidase (GPX), glutathione S-transferase (GST), and superoxide dismutase (SOD) activities, hepatic phosphoenolpyruvate carboxykinase 1 (Pck1), and intestinal solute carrier family 5 member 1 (Slc5a1) mRNA levels compared with the control diet. However, the HF diet with Tucum-do-Cerrado decreased hepatic glycogen, and increased hepatic GR activity, hepatic Slc2a2 mRNA levels and serum Tnfa compared with the HF diet. Tucum-do-Cerrado decreased muscle glycogen, intestinal CAT and GPX activities, muscle PFK-1 and HK activities, and increased hepatic protein (CARB) and intestinal lipid (MDA) oxidation, hepatic GST activity, serum antioxidant potential, hepatic phosphofructokinase-1 (PFK-1) activity, intestinal solute carrier family 2 member 2 (Slc2a2), tumor necrosis factor (Tnf), interleukin-1 beta (Il1b), muscle protein kinase AMP-activated alpha 1 (Prkaa1), solute carrier family 2 member 2 (Slc2a2) mRNA levels, and serum interleukin-6 (IL-6) levels, regardless of diet type.
CONCLUSION
Tucum-do-Cerrado consumption may ameliorate impaired glucose utilization in a HF diet-induced obesity model by increasing liver and muscle glucose uptake and oxidation. These data suggest that Tucum-do-Cerrado consumption improves muscle glucose oxidation in non-obese and obese rats. This response may be related to the improvement in the total antioxidant capacity of rats.
Topics: Rats; Animals; Glucose; Antioxidants; Diet, High-Fat; Liver Glycogen; Obesity; Liver; Arecaceae; RNA, Messenger
PubMed: 38206915
DOI: 10.1371/journal.pone.0293627 -
Nutrients Dec 2023Type 2 diabetes mellitus (T2DM) has become a worldwide public health problem. Epimedin C is considered one of the most important flavonoids in , a famous edible herb in...
Type 2 diabetes mellitus (T2DM) has become a worldwide public health problem. Epimedin C is considered one of the most important flavonoids in , a famous edible herb in China and Southeast Asia that is traditionally used in herbal medicine to treat diabetes. In the present study, the therapeutic potential of epimedin C against T2DM was ascertained using a mouse model, and the mechanism underlying the hypoglycemic activity of epimedin C was explored using a label-free proteomic technique for the first time. Levels of fasting blood glucose (FBG), homeostasis model assessment of insulin resistance (HOMA-IR), and oral glucose tolerance, as well as contents of malondialdehyde (MDA) and low-density lipoprotein cholesterol (LDL-C) in the 30 mg·kg epimedin C group (EC30 group), were significantly lower than those in the model control group (MC group) ( < 0.05), while the contents of hepatic glycogen, insulin, and high-density lipoprotein cholesterol (HDL-C), as well as activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the EC30 group were notably higher than those in the MC group ( < 0.05). The structures of liver cells and tissues were greatly destroyed in the MC group, whereas the structures of cells and tissues were basically complete in the EC30 group, which were similar to those in the normal control group (NC group). A total of 92 differentially expressed proteins (DEPs) were enriched in the gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. In the EC30 vs. MC groups, the expression level of cytosolic phosphoenolpyruvate carboxykinase (Pck1) was down-regulated, while the expression levels of group XIIB secretory phospholipase A2-like protein (Pla2g12b), apolipoprotein B-100 (Apob), and cytochrome P450 4A14 (Cyp4a14) were up-regulated. According to the KEGG pathway assay, Pck1 participated in the gluconeogenesis and insulin signaling pathways, and Pla2g12b, Apob, and Cyp4a14 were the key proteins in the fat digestion and fatty acid degradation pathways. Pck1, Pla2g12b, Apob, and Cyp4a14 seemed to play important roles in the prevention and treatment of T2DM. In summary, epimedin C inhibited Pck1 expression to maintain FBG at a relatively stable level, promoted Pla2g12b, Apob, and Cyp4a14 expressions to alleviate liver lipotoxicity, and protected liver tissues and cells from oxidant stress possibly by its phenolic hydroxyl groups.
Topics: Humans; Hypoglycemic Agents; Diabetes Mellitus, Type 2; Proteomics; Flavonoids; Insulin; Phosphoenolpyruvate Carboxykinase (ATP); Cholesterol
PubMed: 38201855
DOI: 10.3390/nu16010025 -
Foods (Basel, Switzerland) Dec 2023Edible fungi polysaccharides are widely sourced and have various physiological activities, including hypoglycemic. Current studies mainly focus on the hypoglycemic...
Edible fungi polysaccharides are widely sourced and have various physiological activities, including hypoglycemic. Current studies mainly focus on the hypoglycemic activity of polysaccharides themselves, while the strength of the hypoglycemic activity of edible fungi polysaccharides from different sources remained elusive. This study compared the hypoglycemic activity of different edible fungi polysaccharides after in vitro fermentation by fecal bacteria, combined with non-targeted metabolomics and 16S rDNA analysis, to screen out potential key metabolites related to the hypoglycemic activity. The results show that the fermentation supernatants of all four edible fungi polysaccharides significantly increased the glucose consumption and glycogen synthesis of IR-HepG2, also up-regulated the level of hexokinase and down-regulated the level of phosphoenolpyruvate carboxylase. All fermentation supernatants could alleviate the insulin resistance of IR-HepG2 cells by regulating the expression levels of genes related to the IRS-1/PI3K/Akt signaling pathway. Gingerglycolipid A, sphinganine 1-phosphate, matricin, tricarballylic acid, N-carbamoylputrescine, nomega-acetylhistamine, tyramine, and benzamide could be considered as potential key metabolites to evaluate the hypoglycemic effects. Their levels were strongly positively correlated with the abundance of , , , , , , , and . These metabolites and microorganisms are closely related to the hypoglycemic activity of edible fungi polysaccharides.
PubMed: 38201125
DOI: 10.3390/foods13010097 -
Frontiers in Molecular Biosciences 2023When is exposed to changing environmental conditions, the expression of many genes is regulated at the transcriptional level. We reported previously that the...
When is exposed to changing environmental conditions, the expression of many genes is regulated at the transcriptional level. We reported previously that the enterococcal MafR protein causes genome-wide changes in the transcriptome. Here we show that MafR activates directly the transcription of the gene, which encodes a hypothetical protein of 111 amino acid residues. We have identified the promoter and demonstrated that MafR enhances the efficiency of this promoter by binding to a DNA site that contains the -35 element. Moreover, our analysis of the OG1RF_10478 protein AlphaFold model indicates high similarity to 1) structures of EIIB components of the bacterial phosphoenolpyruvate:carbohydrate phosphotransferase system, and 2) structures of receiver domains that are found in response regulators of two-component signal transduction systems. However, unlike typical EIIB components, OG1RF_10478 lacks a Cys or His residue at the conserved phosphorylation site, and, unlike typical receiver domains, OG1RF_10478 lacks a conserved Asp residue at the position usually required for phosphorylation. Different from EIIB components and receiver domains, OG1RF_10478 contains an insertion between residues 10 and 30 that, according to ColabFold prediction, may serve as a dimerization interface. We propose that OG1RF_10478 could participate in regulatory functions by protein-protein interactions.
PubMed: 38192335
DOI: 10.3389/fmolb.2023.1294974 -
Frontiers in Plant Science 2023The content and proportion of sugars and acids in tomato fruit directly affect its flavor quality. Previous studies have shown that 5-aminolevulinic acid (ALA) could...
The content and proportion of sugars and acids in tomato fruit directly affect its flavor quality. Previous studies have shown that 5-aminolevulinic acid (ALA) could promote fruit ripening and improve its aroma quality. In order to explore the effect of ALA on sugar and acid quality during tomato fruit development, 0, 100, and 200 mg L ALA solutions were sprayed on the fruit surface 10 days after pollination of the fourth inflorescence, and the regulation of ALA on sugar, acid metabolism and flavor quality of tomato fruit was analyzed. The results showed that ALA treatment could enhance the activities of acid invertase (AI), neutral invertase (NI), and sucrose synthase (SS), reduce the activity of sucrose phosphate synthase (SPS), up-regulate the expression of , and , change the composition and content of sugar in tomato fruit at three stages, significantly increase the content of sugars in fruit, and promote the accumulation of sugars into flesh. Secondly, ALA treatments increased the activities of phosphoenolpyruvate carboxykinase (PEPC), malic enzyme (ME), and citrate synthase (CS), up-regulated the expression of , , and , and reduced the citric acid content at maturity stage, thereby reducing the total organic acid content. In addition, ALA could also increase the number and mass fraction of volatile components in mature tomato fruits. These results indicated that exogenous application of ALA during tomato fruit development could promote the formation of fruit aroma quality and were also conducive to the formation of fruit sugar and acid quality.
PubMed: 38186602
DOI: 10.3389/fpls.2023.1323048 -
Endocrinology and Metabolism (Seoul,... Feb 2024Sodium-dependent glucose cotransporter 2 (SGLT2) mediates glucose reabsorption in the renal proximal tubules, and SGLT2 inhibitors are used as therapeutic agents for...
BACKGRUOUND
Sodium-dependent glucose cotransporter 2 (SGLT2) mediates glucose reabsorption in the renal proximal tubules, and SGLT2 inhibitors are used as therapeutic agents for treating type 2 diabetes mellitus. This study aimed to elucidate the effects and mechanisms of SGLT2 inhibition on hepatic glucose metabolism in both serum deprivation and serum supplementation states.
METHODS
Huh7 cells were treated with the SGLT2 inhibitors empagliflozin and dapagliflozin to examine the effect of SGLT2 on hepatic glucose uptake. To examine the modulation of glucose metabolism by SGLT2 inhibition under serum deprivation and serum supplementation conditions, HepG2 cells were transfected with SGLT2 small interfering RNA (siRNA), cultured in serum-free Dulbecco's modified Eagle's medium for 16 hours, and then cultured in media supplemented with or without 10% fetal bovine serum for 8 hours.
RESULTS
SGLT2 inhibitors dose-dependently decreased hepatic glucose uptake. Serum deprivation increased the expression levels of the gluconeogenesis genes peroxisome proliferator-activated receptor gamma co-activator 1 alpha (PGC-1α), glucose 6-phosphatase (G6pase), and phosphoenolpyruvate carboxykinase (PEPCK), and their expression levels during serum deprivation were further increased in cells transfected with SGLT2 siRNA. SGLT2 inhibition by siRNA during serum deprivation induces nuclear localization of the transcription factor forkhead box class O 1 (FOXO1), decreases nuclear phosphorylated-AKT (p-AKT), and p-FOXO1 protein expression, and increases phosphorylated-adenosine monophosphate-activated protein kinase (p-AMPK) protein expression. However, treatment with the AMPK inhibitor, compound C, reversed the reduction in the protein expression levels of nuclear p- AKT and p-FOXO1 and decreased the protein expression levels of p-AMPK and PEPCK in cells transfected with SGLT2 siRNA during serum deprivation.
CONCLUSION
These data show that SGLT2 mediates glucose uptake in hepatocytes and that SGLT2 inhibition during serum deprivation increases gluconeogenesis via the AMPK/AKT/FOXO1 signaling pathway.
Topics: Humans; AMP-Activated Protein Kinases; Diabetes Mellitus, Type 2; Gluconeogenesis; Glucose; Phosphoenolpyruvate Carboxykinase (ATP); Proto-Oncogene Proteins c-akt; RNA, Small Interfering; Signal Transduction; Sodium; Sodium-Glucose Transporter 2; Sodium-Glucose Transporter 2 Inhibitors
PubMed: 38171209
DOI: 10.3803/EnM.2023.1786 -
Plant Physiology and Biochemistry : PPB Jan 2024Phosphoenolpyruvate carboxylase (PEPC; EC 4.1.1.31) is an enzyme family with pivotal roles in plant carbon and nitrogen metabolism. A main role for non-photosynthetic...
Phosphoenolpyruvate carboxylase (PEPC; EC 4.1.1.31) is an enzyme family with pivotal roles in plant carbon and nitrogen metabolism. A main role for non-photosynthetic PEPC is as anaplerotic enzyme to load tricarboxylic acid (TCA) cycle with carbon skeletons that compensate the intermediates diverted for biomolecule synthesis such as amino acids. When plants are grown under ammonium (NH) nutrition, the excessive uptake of NH often provokes a stress situation. When plants face NH stress, N assimilation is greatly induced and thus, requires the supply of carbon skeletons coming from TCA cycle. In this work, we addressed the importance of root PEPC and TCA cycle for sorghum (Sorghum bicolor L. Moench), a C4 cereal crop, grown under ammonium nutrition. To do so, we used RNAi sorghum lines that display a decrease expression of SbPPC3 (Ppc3 lines), the main root PEPC isoform, and reduced root PEPC activity. SbPPC3 silencing provoked ammonium hypersensitivity, meaning lower biomass accumulation in Ppc3 respect to WT plants when growing under ammonium nutrition. The silenced plants presented a deregulation of primary metabolism as highlighted by the accumulation of NH in the root and the alteration of normal TCA functioning, which was evidenced by the accumulation of organic acids in the root under ammonium nutrition. Altogether, our work evidences the importance of non-photosynthetic PEPC, and root TCA cycle, in sorghum to deal with high external NH availability.
Topics: Ammonium Compounds; Phosphoenolpyruvate Carboxylase; Sorghum; Citric Acid Cycle; Carbon
PubMed: 38154297
DOI: 10.1016/j.plaphy.2023.108312