Search Results (976)

Fructophilic lactic acid bacteria (FLAB), Apilactobacillus kunkeei strains AG8 and AG9 were selected in the current study for in-depth analysis. Cultivation on fructose yeast peptone (FYP) medium with varying fructose concentrations (1%, 10%, and 30%) revealed that higher fructose levels promoted acetate production over lactate, confirming a heterofermentative metabolic profile. Ethanol production was negligible, consistent with the absence of alcohol dehydrogenase (ADH) activity. Enzyme assays showed fructokinase activity doubled at 30% fructose, while acetate kinase activity increased and L-lactate dehydrogenase activity decreased. This shift in enzyme ratios from 1:1 at 1% fructose to 10:1 or 15:1 at higher concentrations explains the metabolic preference for acetate. Apb. kunkeei is an obligate FLAB, growing poorly on glucose unless supplemented with external electron acceptors like pyruvate or oxygen. It lacks ADH, but retains acetaldehyde dehydrogenase (ALDH), enabling acetate production and additional ATP generation, enhancing biomass yield. The absence of the adhE gene contributes to NAD+/NADH imbalance and favors acetate production. Gene expression studies targeting fructose transport enzymes showed elevated expression of ABC transporters and carbohydrate metabolism genes in response to fructose. ADH expression remained low across sugar concentrations. Fructokinase gene expression was shown to be strain specific. Neither strain expressed the ABC transporter ATP-binding protein gene on glucose, nor the bacteriocin ABC transporter gene, correlating with the absence of antibacterial activity. These findings underscore the metabolic specialization of Apb. kunkeei, its reliance on fructose, and the role of ABC transporters in optimizing fermentation. The strain-specific gene expression and metabolic flexibility highlight its potential as a probiotic and feed additive in apiculture and biotechnology. Full article

The young stem of rapeseed is a highly nutritional vegetable, but there is a lack of information on quality regulation by slow-release fertilizers (SRFs). This study aims to evaluate the effects of SRFs on nutritional contents, including vitamin and sugar profiles and regulatory mechanisms, using enzymatic activity and gene expression analysis. A field experiment was conducted with a split-plot design, in which treatments with two fertilizers (traditional compound fertilizer (TF) and SRF) served as the main plot and two harvesting stages (main stem harvesting (S1) and the first branch harvesting (S2)) served as the sub-plot. The results showed that vitamin E (VE) content under the SRF treatment was 48.31% and 18.44% higher than that under the TF treatment at both stages. The contents of vitamin C (Vc) at the S2 stage and vitamin B6 (VB6) at the S1 stage under the TF treatment were 7.56% and 2.95% higher than under SRF treatments. Water-soluble sugar (WSS) and glucose contents under the SRF treatment were significantly higher than under the TF treatment at both stages, while fructose, trehalose, and sorbitol contents exhibited the opposite trend. The offset effect of the activity of ascorbate oxidase (AAO) and dehydroascorbate reductase (DHAR) between the two fertilizers resulted in a non-significant difference in Vc content at the S1 stage. Under the TF treatment, sucrose phosphate synthase had greater activity as compared to the SRF treatment. The selected key genes involved in vitamin and carbohydrate metabolism were generally in agreement with the changes in enzymatic activity. This study highlights the importance of SRF for the quality formation of young stems of rapeseed as a vegetable. Full article

Fructose malabsorption is characterized as the incomplete absorption of fructose in the small intestine. Fructose is one of the most common monosaccharides in the human diet. The purpose of this review is to provide an updated overview of insights into the relationship between high-fructose diet, fructose malabsorption, gut microbiota and clinical consequences. Incomplete absorption of fructose causes accumulation in the colon, which leads to fermentation by gut microbiota and abdominal symptoms such as bloating and excessive gas production. Malabsorption may result from exceeding the absorptive capacity of GLUT5 or insufficient upregulation, with incidence increasing with age and higher dietary fructose concentrations. High-fructose diets generally promote an increase in inflammatory bacterial groups such as Desulfovibrio and Deferribacteraceae, while reducing beneficial Bacteroidetes. These microbial alterations may impair intestinal barrier function, modify short-chain fatty acid profiles, and contribute to systemic inflammation, metabolic disorders, and potentially mental health issues. Animal studies using fructose malabsorption models present inconclusive results regarding the impact of fructose on the composition of gut microbiota. Additional research is essential to fully comprehend the complex relationship between diet, fructose malabsorption and gut microbiota, to develop personalized, effective dietary approaches for managing symptoms of fructose malabsorption. Full article

A hypercaloric diet is associated with oxidative stress and the dysfunction of ATP-Binding Cassette transporter A1 (ABCA1), a key element in high-density lipoprotein (HDL) biogenesis and reverse cholesterol transport. Nicotinamide (NAM) presents antioxidant properties, which may contribute to maintaining lipid metabolism. Therefore, we aimed to evaluate the effect of NAM on HDL-cholesterol (HDL-C) level, oxidative stress markers, and the gene expression and protein levels of ABCA1 in Sprague-Dawley rats fed a hypercaloric diet. Forty male rats were divided into five groups: one group received a standard diet, and the remaining groups received a single high-fat, high-fructose diet (HFDF). Three of the HFDF groups received NAM treatment (5, 10, and 15 mM) in drinking water for 16 weeks (5 h/day). While HDL-C and oxidative stress were measured in serum samples, oxidative stress markers, and the gene expression and protein levels of ABCA1 were quantified in liver samples. The HDL-C level altered by the HFDF was improved by treatment with NAM. Furthermore, NAM reduces systemic lipid peroxidation levels and enhances the hepatic antioxidant response affected by the HFDF. In addition, NAM modulates the hepatic ABCA1 gene expression and protein level, altered by the HFDF. Our results suggest that NAM may modify the serum HDL-C level by an improvement of antioxidant response, and a possible modulation of the hepatic ABCA1 gene and protein expression. Further metabolic and molecular studies are needed to support the potential therapeutic role of NAM to prevent or treat lipid alterations promoted by a hypercaloric diet. Full article

Total Soluble Solids (TSS) in tomatoes is a core indicator for evaluating fruit quality and processing characteristics. Its composition mainly consists of soluble sugars (such as fructose and glucose) and organic acids (such as citric acid and malic acid). The contents of sugars and acids and their ratio directly affect the flavor and nutritional value. Cultivated tomatoes have a TSS of 4–6%, compared with 10–15% in wild varieties. In recent years, with the advancement of molecular biology and genomics technologies, significant progress has been made in the research on the regulatory mechanisms of tomato fruit TSS and major sugars and acids, including the identification of major quantitative trait locus (QTLs) (Lin5, SlALMT9), functional characterization via CRISPR/Cas9 and elucidation of the transporter network. Breaking the negative correlation between TSS and yield remains a major bottleneck in breeding. Analyzing the mechanism by which environmental factors regulate the TSS and optimizing cultivation measures are crucial for increasing the TSS content in tomatoes. The deep integration of cutting-edge technologies (such as Genome-wide association studies (GWAS), metabolome-wide association studies (mGWAS), Genomic selection (GS), genome editing, and crop modeling) with design breeding is expected to accelerate the development of high-TSS tomato varieties. This paper reviews the current research status from the following four aspects: QTL mapping related to tomato TSS and mining of major genes, metabolic and transport mechanisms of major sugars and acids and key genes, the influence of environmental factors on TSS, and application of genetic improvement strategies and technologies. Full article

Korean melon (K-melon, Cucumis melo L. var. makuwa) is a key horticultural crop in the Republic of Korea, but its short shelf life restricts long-distance export. This study evaluated the modified atmosphere (MA) films of varying oxygen transmission rates (OTR) at controlled atmosphere (CA) storage under real maritime export conditions to Vietnam. In the non-permeable OTR 0 (Control) treatment, internal O₂ rapidly declined below the anaerobic compensation point (1.67% at 10d and 0.47% at 10+3d) while CO₂ accumulated to 32–36%. This ultra-low oxygen environment induced anaerobic metabolism, evidenced by strong accumulation of fermentative metabolites such as lactic acid, acetoin, and 2,3-butanediol, along with glucose/fructose retention and increases in alanine and γ-Aminobutanoic acid (GABA). These changes disrupted glycolysis and the Tricarboxylic acid cycle (TCA), consistent with CA shock, and were accompanied by rind blackening, elevated weight loss, and hue angle shifts toward yellow-orange. By contrast, OTR 10,000 and OTR 30,000 films significantly suppressed weight loss and color changes. Partial least squares-discriminant analysis (PLS-DA) identified volatile organic compounds, namely acetoin, 2,3-butanediol, and hexanal, as key discriminant metabolites, with OTR 30,000 clearly separated from other treatments at 10+3d, indicating minimal fermentation and oxidative stress. Microbial assays revealed a dose-dependent reduction in bacterial counts with increasing OTR, while fungal growth was most strongly suppressed under OTR 10,000. Overall, OTR 30,000 maintained the lowest and most stable levels of stress-related metabolites, minimized microbial proliferation, and preserved metabolic stability throughout shipping. This study provides the first quantitative evidence of anaerobic metabolic transition and primary metabolite accumulation in K-melons under actual export trials. The findings demonstrate that optimizing MA film permeability, particularly OTR 30,000 films, offers a practical and cost-efficient strategy to extend shelf life, maintain quality stability, and enhance the global export potential of K-melons. Full article

Nitrogen-modified atmosphere technology, due to its effectiveness in pest control, is widely used in grain storage as an eco-friendly preservation method. This study compared the quality changes in unhulled rough rice (paddy) stored under nitrogen-modified atmosphere and conventional conditions. Fatty acid value (FAV), reactive oxygen species (ROS) content, coenzyme levels, antioxidant enzyme activities, and concentrations of central carbon metabolism-related metabolites of paddy were monitored during storage under different storage conditions. The results revealed that compared to conventional storage, nitrogen-modified atmosphere resulted in lower FAV and ROS levels, as well as higher pyridine nucleotides contents and antioxidant enzyme activities, including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and glutathione reductase (GR). Metabolomic profiling demonstrated that N₂-MAS induced metabolic changes characterized by the down-regulation of 2-hydroxyglutaric acid and the up-regulation of fructose 6-phosphate, glucose 1-phosphate, glycerol 3-phosphate, gluconic acid, fumaric acid, and malic acid, which collectively contribute to reduced oxidative damage and enhanced preservation quality. These findings elucidated the mechanism of N₂-MAS-delayed quality deterioration and revealed the regulatory role of the antioxidant system and central carbon metabolism. Full article

This study investigated the effects of replacing part of the soybean meal in the diet of Dumont lambs with urea, rapeseed meal, and cottonseed meal on their growth performance and rumen fermentation and combined rumen microbial metagenomics and metabolomics to explain the reasons for the changes in phenotypic data. Twenty-four healthy male Dumont lambs were divided into four groups: soybean meal group (T1, control group), group with 1.5% urea replacing 6.4% soybean meal (T2), group with 1% urea replacing 4.3% soybean meal (T3), and group with 1% urea + 6.6% cottonseed meal +5% rapeseed meal replacing all soybean meal (19%) (T4), following the principle of equal energy and nitrogen. Urea, rapeseed meal, and cottonseed meal have different degradation rates in the rumen, primarily stimulating arginine biosynthesis, sulphur metabolism, and carbon fixation in photosynthetic organisms through Prevotella genus mediation, thereby influencing the accumulation of metabolites such as 9,10-DiHOME, DG (PGJ2/a-15:0/0:0), isonicotinate and taxifolin, affecting rumen fermentation. Compared with the T1 group, the T2 group showed significantly increased ammonia nitrogen (NH₃-N) and microbial protein (MCP) content (p < 0.01) and improved fructose and mannose metabolic capacity (p < 0.05). The T3 group showed a significant increase in total volatile fatty acids (TVFA) and MCP content (p < 0.01), which facilitated the absorption of subsequent nutrients. In the T4 group, different degradation rates of nitrogen resources and rapeseed meal + cottonseed meal contained abundant and complementary amino acids, which improved rumen fermentation, enhanced rumen microbial and metabolite diversity, and optimized the synergistic metabolic efficiency of carbon, nitrogen and sulphur. However, the specific mechanisms of post-rumen metabolism and absorption require further investigation. Full article

Sugars function as essential signaling molecules and metabolic substrates in plant growth, development, yield formation, and fruit quality. The aril of litchi (Litchi chinensis Sonn.) accumulates high levels of hexoses, primarily glucose and fructose; however, the molecular mechanisms underlying this process remain poorly characterized. This study aimed to systematically identify the monosaccharide transporter (MST) gene family in litchi and elucidate its role in aril sugar accumulation. Through a comprehensive analysis of the litchi genome, we identified a total of 45 LcMST genes, which were classified into seven distinct subfamilies: STP, ERD6L, PLT, INT, pGlcT, TMT, and VGT. Analysis of gene structure and conserved motifs revealed notable conservation among members within the same subfamily. Collinearity and gene duplication analyses suggested that the LcMST family expanded through both tandem and whole-genome duplication events, a process primarily governed by purifying selection. Expression profiling across diverse tissues demonstrated that LcMST genes exhibit distinct tissue-specific expression patterns. During fruit development in the hexose-dominant cultivar ‘Tianshuili’, the expression of the tonoplast monosaccharide transporter gene LcTMT1 exhibited a significant positive correlation with the accumulation of fructose, glucose, and total sugars. Heterologous functional complementation assays in yeast confirmed the ability of LcTMT1 to transport both glucose and fructose. In conclusion, this study presents the first genome-wide identification and characterization of the MST gene family in litchi, and identifies LcTMT1 as a key contributor of hexose accumulation in the aril. These findings establish a foundation for elucidating the molecular mechanisms of sugar accumulation in litchi fruit and for guiding future genetic improvement of fruit quality. Full article

Bats have unique reproductive strategies that are closely related to testicular metabolic adaptations, such as prolonged sperm storage. This study examined the expression of glucose transporter 5 (GLUT-5), a fructose-specific member of the facilitative glucose transporter family, in the testes of roundleaf bats (Hipposideros spp.) collected from various locations in Thailand during their active reproductive season (July to September) and explored its association with biometric traits. To assess GLUT-5’s localization and expression levels, testicular tissues from 50 adult males representing Hipposideros larvatus, Hipposideros armiger, and Hipposideros lekaguli species were analyzed using immunohistochemistry and Western blotting. Strong GLUT-5 immunoreactivity was observed in the cytoplasm of spermatocytes, spermatids, and spermatozoa, while weak staining was seen in spermatogonia. No GLUT-5 expression was detected in Leydig or Sertoli cells. Staining intensity varied significantly by month, with the highest levels observed in August (p < 0.05), exceeding those in July and September. Western blotting identified two GLUT-5 isoforms (55 and 100 kDa), with relative intensities that changed across the reproductive timeline. In parallel, morphometric analysis revealed that the height of the germinal epithelium and the diameter of the seminiferous tubules were significantly greater in July than in August and September, reflecting peak spermatogenic activity. These findings suggest that the seasonal regulation of fructose transport, along with changes in testicular architecture, may support testicular function and sperm maturation. The differential expression of GLUT-5 isoforms may reflect their distinct roles in body growth, reproductive maturation, and seasonal testicular activity in Hipposiderid bats. Full article

Analyzing the biochemical and physiological activities of food microbes using molecular and bioinformatics tools is important, offering profound insights into their safety, functional, and applicational roles in food. In this study, Lactiplantibacillus plantarum NMGL2, a well-documented beneficial lactic acid bacteria (LAB) strain, was investigated for its genomic, metabolic, and transcriptomic characteristics. Whole-genome sequencing revealed that this strain possesses a chromosome and two plasmids, with 3320 annotated genes, showcasing pathways involved in carbohydrate metabolism, stress adaptation, and bioactive compound synthesis. Growth studies under various nutritional conditions, including fructose, lactose, exogenous exopolysaccharide (EPS), and soy peptone, demonstrated that nitrogen source alteration significantly enhanced bacterial growth and EPS production. Transcriptomic analysis showed the addition of EPS and soy peptone resulted in similar regulatory patterns, suggesting shared modulation of metabolic pathways, although distinct gene regulation patterns were involved. In contrast, fructose and lactose primarily regulated carbohydrate metabolism without increasing EPS yield. Prophage gene clusters were consistently down-regulated across all experimental conditions, reflecting the strain’s adaptive response. These findings highlight L. plantarum NMGL2’s ability to dynamically adjust its metabolism and gene expression in response to environmental and nutritional changes, offering valuable insights for its application in functional foods and probiotics. These results also imply the potential of LAB strains in bioactive compound production and health-related applications through metabolic engineering. Full article

TAAR1 agonists have emerged as promising therapeutic agents capable of modulating glucose homeostasis, enhancing insulin secretion and suppressing appetite, making them attractive candidates for the treatment of obesity and related metabolic disorders. Despite their potential, the number of TAAR1-targeting compounds with well-defined pharmacological profiles remains limited. In this study, we identified and characterized JP-14, a novel aminoguanidine-based TAAR1 agonist, in a comprehensive panel of pharmacological assays. JP-14 promoted glucose uptake in HepG2 cells and reduced lipid deposition during 3T3-L1 adipocyte differentiation, with both actions dependent on TAAR1 signaling. In differentiated 3T3-L1 adipocytes, JP-14 reduced intracellular levels of both neutral lipids and phospholipids, indicating dual anti-steatotic and anti-phospholipidotic activity. In zebrafish larvae, toxicity profiling confirmed 10 µg/mL as a safe concentration for further in vivo studies. These assays showed that JP-14 promoted lipid mobilization and partially prevented fructose-induced lipid accumulation, demonstrating systemic metabolic benefits in vivo. Moreover, JP-14 markedly delayed gastric emptying in mice, an effect similar to loperamide and reversed by TAAR1 antagonism, supporting its role in regulating satiety and energy balance. Collectively, our findings establish JP-14 as a safe and metabolically active TAAR1 agonist with multifaceted effects on glucose and lipid metabolism. JP-14 represents a valuable pharmacological tool for probing TAAR1-mediated mechanisms in metabolic regulation. Full article

Background: Due to the continuous global rise in obesity prevalence, foods rich in bioactive compounds are increasingly recognised for the management of several diseases. Objective: The present study aims to investigate whether an Opuntia stricta var. dillenii fruit peel extract, rich in betalains and phenolic compounds, is able to prevent obesity induced by a high-fat high-fructose diet in rats, along with the potential mechanisms of action underlying this effect. Results: The supplementation with Opuntia stricta var. dillenii extract obtained from the peel fruit partially prevents obesity development by attenuating HFHF-induced fat accumulation. This effect was observed predominantly in visceral adipose tissue, rather than in the subcutaneous depot. The obesity prevention was accompanied by the improvement of serum lipid profile. The mechanisms underlying the extract anti-obesity effect which were analysed in epididymal adipose tissue, involve preventing the rise in the availability of triglyceride synthesis substrates induced by high-fat high-fructose feeding, the inhibition of triglyceride assembly, and in the case of the high dose, increased lipolysis. Conclusions: According to these results, the peel wastes of Opuntia stricta var. dillenii fruit represent a promising natural source of bioactive compounds for obesity prevention. Nevertheless, these preclinical effects should be replicated in further studies in human beings. Full article

To elucidate the flavor substance basis of the pear germplasm resources in Xinjiang, this study conducted precise qualitative and quantitative analysis of sugars and organic acids in the fruits of 29 pear cultivars. Fructose and glucose are the dominant sugars, accounting for 64.0% of the total sugar content. Malic acid is the dominant organic acid, accounting for 85.8% of the total acid content. The cultivar LL exhibited the highest total sugar content at 633.6 mg·g⁻¹, while cultivar JJL-1 showed the highest total acid content at 1441.3 μg·g⁻¹. Early-ripening (ER) cultivars demonstrated significantly higher sucrose content compared to mid-ripening (MR) and late-ripening (LR) cultivars, while late-ripening cultivars contained the highest total acid content. These findings provide essential phenotypic data for understanding the genetic basis of sugar and acid metabolism in pear fruits and establish a scientific foundation for parent selection in breeding high-quality pear cultivars in Xinjiang. Full article

Excessive maternal fructose intake contributes to the developmental programming of hypertension in offspring, partly via gut microbiota dysbiosis and oxidative stress. Fecal microbiota transplantation (FMT) may restore microbial balance and modulate short-chain fatty acid (SCFA) production. We investigated whether maternal FMT from healthy donors could prevent hypertension in offspring exposed to a high-fructose (HF) diet. Pregnant Sprague Dawley rats (n = 12) were fed normal chow (ND) or a 60% HF diet from mating to delivery. Cross-FMT was performed: HF dams received FMT from ND donors, and ND dams received FMT from HF donors. Male offspring (n = 8/group) were assigned to ND, HF, ND + HF-FMT, or HF + ND-FMT groups. Offspring of HF dams developed higher systolic blood pressure (+13 mmHg vs. ND, p < 0.05). Maternal FMT from ND donors reduced this elevation by ~8 mmHg (p < 0.05). Protective effects were accompanied by higher plasma butyrate, increased expression of SCFA receptors (GPR41, GPR43), reduced renal oxidative stress markers (8-OHdG), and distinct gut microbiota profiles. Maternal FMT generated four enterotypes in offspring, each associated with differential blood pressure outcomes. These findings suggest that maternal microbiota-targeted interventions, such as FMT, can mitigate hypertension of developmental origin by restoring gut microbial and metabolic homeostasis. Full article