Search Results (118)

Fruit sweetness is a key trait that determines the quality of fresh raspberries and meets processing requirements. It is mainly regulated by the content of soluble sugars and organic acids. However, there is still a lack of systematic research on the molecular mechanisms of sugar accumulation during the development of raspberry fruits. This study used the raspberry variety ‘Caroline’ as material. By detecting changes in sugar content during fruit development and ripening, combined with transcriptomic analysis of related differentially expressed genes, it was found that the differentially expressed gene RiPFK2 was significantly upregulated during the period of rapid sugar accumulation in the fruit. We constructed an RiPFK2 overexpression vector and found that fructose content significantly increased in transgenic tomatoes and raspberries, indicating that this gene positively regulates fructose accumulation. This study is the first to reveal the positive regulatory role of PFK family members in fructose accumulation in raspberry fruits, providing a theoretical basis for improving raspberry fruit quality. Full article

This study investigated the effects of dietary carbohydrate levels on growth performance, body composition, and hepatic expression of metabolic genes in Chinese hook snout carp (Opsariichthys bidens). Fish were fed five isonitrogenous diets with graded α-starch levels (8%, 14%, 20%, 26%, and 32%) for 56 days. The diet containing 14% α-starch significantly increased the weight gain rate (WGR) and specific growth rate (SGR) of O. bidens (p < 0.05). Both broken-line and polynomial regression analyses on WGR and SGR consistently indicated an optimal dietary α-starch level of approximately 14–17%. High carbohydrate diets significantly elevated plasma glucose, triglyceride, and cholesterol levels, as well as hepatosomatic and intraperitoneal fat indices. Gene expression analysis revealed that moderate carbohydrate intake upregulated lipoprotein lipase (lpl), hormone-sensitive lipase (hsl), and carnitine palmitoyltransferase 1 (cpt1) gene expressions, enhancing lipolysis and β-oxidation, whereas excessive carbohydrate intake (>26% α-starch) suppressed these pathways but strongly induced acc1 gene expressions, promoting lipogenesis. Additionally, glycogen metabolism genes (glycogen synthase (gys) and glycogen phosphorylase (pyg) and glycolysis-related phosphofructokinase (pfk) were responsive to carbohydrate supply, while oxidative metabolism gene cs was downregulated under excessive carbohydrate, implying reduced mitochondrial oxidative metabolism. Overall, O. bidens exhibited limited carbohydrate utilization, with optimal intake supporting growth and metabolic balance, whereas excessive intake redirected glucose toward glycogen and lipid accumulation, leading to metabolic imbalance. Full article

Itaconic acid (IA), one of the top twelve renewable platform chemicals, is a key precursor for polymer synthesis. Here, we engineered Myceliophthora thermophila for efficient consolidated biocatalytic IA production from lignocellulose by introducing the heterologous IA pathway (cis-aconitic acid decarboxylase (CAD), mitochondrial tricarboxylic transporter (MTT), major facilitator superfamily transporter (MFS) from Aspergillus terreus), and boosting CAD expression and precursor supply. A critical issue was temperature mismatch: optimal fungal growth vs. CAD activity. Transcriptomics analysis identified reduced expression of glycolytic rate-limiting enzymes (fructose-bisphosphate aldolase, FBA; phosphofructokinase, PFK) at 40 °C. Overexpressing these enzymes in strain IA32 generated strain IA41 (with 3.1-fold and 2.8-fold higher expression of pfk and fba, respectively), which accelerated glucose consumption by 53.2% and increased IA yield by 55.1% A two-stage temperature-shift strategy (45 °C for growth/saccharification, 40 °C for CAD activity) was developed. The engineered strain achieved 3.93 g/L IA in shake flasks and 10.51 g/L in corncob fed-batch fermentation—the highest reported titer for consolidated lignocellulose-to-IA processes. This establishes M. thermophila as a robust platform for cost-effective IA production from lignocellulose. Full article

Heat stress induced by high temperature and humidity in southern China during summer reduce goat production efficiency and meat quality. Taurine (TAU), one of the most abundant amino acids in animal tissues, plays a vital role in alleviating heat stress and regulating energy metabolism through its involvement in glucose uptake and glycogen turnover. This study aimed to investigate the effects of rumen-protected (RP)-TAU on the meat quality, hepatic gluconeogenesis, and muscle energy metabolism of heat-stressed goats. During summer, twenty-four male crossbred Gan-xi goats (20.45 ± 2.95 kg) aged 5 months were randomly allocated to two groups treated with or without 0.4% RP-TAU (on a diet weight basis). After feeding for 60 days, six goats per treatment were slaughtered. Compared with the control group, RP-TAU supplementation significantly improved the growth performance of goats, as evidenced by increased final body weight, average daily gain, and average daily feed intake (p < 0.05). The goats in the RP-TAU group showed a reduced splenic index (p < 0.05), lower serum cortisol levels (0.05 < p < 0.1), and decreased muscle crude fat content (p < 0.01). Crucially, meat quality was improved with reduced hardness, gumminess, and chewiness (p < 0.05), indicating better textural properties. Nutritionally, RP-TAU supplementation modulated the muscle fatty acid profile, significantly reducing the concentrations of palmitic (a saturated fatty acid), palmitoleic (a monounsaturated fatty acid), and nervonic acids (p < 0.05), while cystine content was reduced (p < 0.05). RP-TAU supplementation significantly enhanced the muscle contents of glucose and glycogen, glycolytic potential, phosphofructokinase activity, and ATP level, while decreasing the pyruvate level and AMP/ATP ratio (p < 0.05). Gene expression analysis revealed the upregulation of GLUT4 and PYGM and the downregulation of GSK3β in muscle (p < 0.05). These results indicated that dietary supplementation of RP-TAU might be beneficial to improve stress resistance and meat quality by increasing muscle energy supply and glucose uptake in Gan-xi goats. Full article

Pollution from heavy metals represents one of the most important threats to crops. Among these, Nickel (Ni) represents a dangerous element, strictly related to anthropic activity and easily accumulated in plants. In this study, effects of high levels (1 mM) of Ni²⁺ were investigated in barley (Hordeum vulgare L. cv. Nure) grown hydroponically, inducing a severe reduction in plant growth, as well as genotoxic damage. Moreover, stress affects photosynthesis, inducing a decrease in Fv/Fm and ΦPSII and an increase in D1 protein and RuBisCO (RbcL) abundance to compensate for the loss of photosynthetic efficiency. Changes were observed in carbon metabolism, with increases in phosphofructokinase, glyceraldehyde-3P dehydrogenase-NAD⁺, and pyruvate kinase expression confirmed by increased proteins and activities. Notably, there was an evident rise in PEP carboxylase activity, presence, and expression. This increase boosts the TCA cycle (increased fumarase) and supports photorespiration. Evident rises were observed also for glucose-6P dehydrogenase activity and presence. Ni²⁺ stress induced an evident increase in enzymes involved in nitrogen metabolism: particularly, the chloroplastic GS2/Fd-GOGAT cycle and N assimilation through the cytosolic glutamate dehydrogenase reaction were enhanced. These results design a specific stress-responsive metabolism by diverting the synthesis of N-compounds through alternative C/N assimilation pathways to counteract the effects of Ni²⁺ toxicity. This study depicts a diversion of the main C/N metabolism network towards an increase in leaf N assimilation, using carbon skeletons from dark CO₂ fixation under high Ni²⁺ stress. These results may provide possible targets for the improvement of heavy metal tolerance in cereals. Full article

The effects of storage temperature (4 °C, −1 °C, and −4 °C) after the very fast chilling (VFC) treatment on the glycolysis in lamb were investigated. The meat tenderness, glycolytic rates, activity, phosphorylation, and acetylation levels of glycolytic enzymes in meat stored at different temperatures were measured. It was shown that there was no significant difference in the degradation degree of desmin and troponin T in meat at different storage temperatures after VFC treatment (p < 0.05). The decrease rate of pH and ATP in meat was the same under different storage temperatures. The promoted phosphorylation and acetylation levels of phosphofructokinase (PFKM) and phosphoglycerate kinase (PGK) and inhibited acetylation level of aldolase (ALDOA) in the samples stored at different temperatures maintained the same glycolytic rate. In conclusion, chilling treatment is the key step in improving meat tenderness rather than storage temperature, which is achieved by the increased phosphorylation of ALDOA, PFKM, and PGK and decreased acetylation of ALDOA. It indicated that the chilling rate promoted the improvement of meat quality mainly by delaying glycolysis compared to the storage temperature. Full article

The phosphofructokinase (PFK) gene family plays a pivotal role in glycolysis and energy metabolism in plants. This study aimed to systematically characterize the PFK gene family in Arabidopsis thaliana at the genome-wide level and to investigate the function of AtPFK2 (ATP-dependent phosphofructokinase 2) in response to salt and drought stress. Through bioinformatics analysis, 11 AtPFK genes were identified. Phylogenetic analysis revealed that these PFK genes can be classified into two subfamilies: PFK and PFP. Notably, AtPFK2 possesses a unique structure, containing only a single intron, and its promoter is enriched with stress- and hormone-responsive elements, such as ABRE and MBS. T-DNA insertion mutants (pfk2) exhibited slightly shorter roots but slightly higher fresh weight under stress conditions, whereas Arabidopsis lines AtPFK2-overexpressing (OE-PFK2) showed increased stress sensitivity, with inhibited root and leaf growth, leaf wilting, reduced malondialdehyde and chlorophyll content, and enhanced accumulation of proline and soluble sugars. Weighted gene co-expression network analysis (WGCNA) identified 14 stress-related modules, from which six core genes—LBD41, TRP3, PP2-A3, SAUR10, IAA6, and JAZ1—were selected. These genes are involved in glycine metabolism and plant hormone signaling. The results of this study indicate that AtPFK2 mediates stress responses by regulating osmoregulatory substances and hormone signaling pathways, offering new insights into the mechanisms of stress resistance in crops. Full article

The focus on selecting broilers for rapid growth rates and enhanced breast muscle yield has resulted in a decline in meat quality. The differences in carcass characteristics and meat quality between Hubbard white broilers (HWs, a commercial breed) and Xueshan chickens (XSs, an indigenous breed) at market age were analyzed to determine the potential mechanisms responsible for these differences. The results show that HWs exhibited significantly better carcass performance than XSs, including the larger weight of the carcass, the breast muscle, and the thigh muscle (p < 0.01). In addition, based on HE staining analysis, HWs’ breast muscles had a considerably larger average myofiber area and diameter than those of XSs (p < 0.01). Furthermore, the physical characteristics of the meat revealed that XSs had higher redness and yellowness and also higher lightness. HW meat had a higher pH and thermal loss, but a lower shear force and drip loss than XS meat (p < 0.01). The content of saturated fatty acids (SFAs) and polyunsaturated fatty acids (PUFAs) was, remarkably, lower in the breast muscles of HWs than of XSs (p < 0.01). In contrast, HWs had a larger concentration of monounsaturated fatty acids (MUFAs) than XSs (p < 0.01). Finally, the breast muscles of XSs had lower levels of mRNA expression for genes linked to lipid metabolism, such as fatty acid binding protein 4 (Fabp4) and peroxisome proliferator-activated receptor alpha (Pparα), and had higher levels of the phosphofructokinase muscle type (Pfkm) compared to HWs (p < 0.01). These results indicate that a lower carcass yield was observed in XSs compared with HWs, but that XSs showed better performance in terms of meat quality than HW. Full article

Ulva prolifera (Chlorophyta), a pivotal species in green tide generation, is particularly vulnerable to abiotic stressors, including variations in temperature and light intensity, requiring specific regulatory frameworks for survival. Epigenetic modification is recognized as a molecular mechanism contributing to the flexible adaptability to environmental alterations. In this study, using DNA methylation pattern analysis, we investigated abiotic stress responsive methylation events, as well as gene and pathway expression patterns, in green macroalgae U. prolifera cultured under elevated temperature–light stress (30 °C and 300 µmol photons m⁻² s⁻¹⁾ and identified a negative correlation between CG methylation and gene expression patterns which indicated that abiotic stress caused CG demethylation and afterwards provoked the transcription response. CHG and CHH methylation exhibited an increased mutability and were preeminently found in transposable elements and intergenic regions, possibly contributing to genetic stability by restricting transposon activity. Furthermore, a rapid regeneration through spore ejection and the formation of new thalli was observed, which emphasized its tenacity capacity for stress memory. Our study also revealed an upregulation of genes associated with the glycolysis pathway and highlighted the critical roles of hexokinase, 6-phosphofructokinase-1, and fructose-6-phosphate in triggering glycolysis as a significant stress-adaptive pathway. Overall, these findings suggested that DNA methylation functions as a potential regulatory mechanism, maintaining environmental adaptability, genomic integrity, and underpinning regenerative capacity in U. prolifera. The findings elucidated the molecular resilience of U. prolifera, highlighting its feasibility for sustainable development and biotechnological applications. Full article

The physiological functions of mammalian sperm, such as motility, hyperactivation, and capacitation, require substantial energy. This study investigates the effects of two classic cryopreservation extenders—TCG (tris-citrate-glucose) and LEY (lactose-egg yolk)—on the energy metabolism of frozen–thawed boar semen. By comparing the quality indicators, key metabolite levels, and the activities of critical enzymes involved in glycolysis and the tricarboxylic acid cycle, we aim to understand how these different semen extenders influence the spermatozoa vitality of frozen–thawed boar semen. Following thawing, the LEY-cryopreserved sperm demonstrated significantly elevated motility parameters (viability, VCL, VSL, and VAP) and enhanced plasma membrane and acrosomal integrity compared with the TCG group (p < 0.05), though both cryopreserved groups exhibited significantly reduced performance relative to fresh semen controls. Cryopreservation markedly reduced intracellular adenosine triphosphate (ATP), pyruvate, and acetyl coenzyme A (A-CoA) levels (fresh > LEY > TCG; p < 0.05). The LEY-preserved spermatozoa retained higher activities of glycolysis-related enzymes (phosphofructokinase, PFK; pyruvate kinase, PK) compared with the TCG group, which, in turn, showed elevated lactate dehydrogenase (LDH) activity. Critically, TCG-suppressed pyruvate dehydrogenase (PDH) activity (p < 0.05) coincided with diminished A-CoA, indicating impaired mitochondrial oxidative phosphorylation. These results demonstrate LEY’s superior preservation of motility and membrane stability but highlight cryodamage-induced energy metabolism dysregulation, particularly TCG’s disruption of the glycolysis–TCA cycle coordination essential for spermatozoa function. In conclusion, the choice of semen extender has a significant impact on the energy metabolism and overall quality of frozen–thawed semen, highlighting the importance of optimizing cryopreservation protocols for improved spermatozoa viability and functionality. Full article

To investigate the effects of straight-line-shape (SL) and inverted-umbrella-shape (IU) training systems on sugar accumulation and metabolism in ‘Kyoho’ grape berries in Fujian, this study used 16-year-old ‘Kyoho’ grapevines trained in the two systems. Fruit samples were collected from 45 to 95 days after flowering (DAF) to measure soluble sugar content. Transcriptome sequencing was performed to analyze the differential expression of sugar metabolism-related genes, combined with KEGG enrichment analysis and RT-qPCR validation of key genes. The results showed that, at the same stage, the soluble sugar content in berries under the SL training system was significantly higher than that under the IU training system, especially from 45 to 65 DAF, where sugar accumulation was faster. Transcriptome analysis revealed that the SL training system showed 6274, 5597, and 2064 differentially expressed genes at 45, 65, and 95 DAF, respectively. Key sugar metabolism-related genes, such as fructokinase (FK), phosphofructokinase (PFK), and sucrose phosphate synthase (SPS), exhibited significantly higher expression levels in the SL training system than in the IU training system. KEGG enrichment analysis indicated that the SL training system significantly enriched sugar metabolism and transport pathways during the early fruit ripening stage. RT-qPCR validation confirmed that genes related to sugar metabolism and transport (such as FK7, SUS3, SPP1) were expressed at significantly higher levels in the SL training system than in the IU training system. In conclusion, the SL training system significantly promoted soluble sugar accumulation and accelerated fruit ripening in ‘Kyoho’ grapes by regulating the expression of sugar metabolism and transport-related genes, providing a theoretical basis for promoting the SL training system in production. Full article

Background: Dietary consumption of insulinogenic amino acids (IAA) is known to contribute to the development of insulin resistance. It remains to be studied whether dietary IAA restriction improves glucose metabolism and insulin sensitivity and whether this improvement is related to alterations in glucose metabolism in peripheral tissues. The objective of this study was to examine the effect of IAA restriction on glucose metabolism in a piglet model. Methods: Following the acclimation period, thirty-two seven-day-old male piglets were randomly assigned into one of three groups for three weeks as follows (n = 10–11/group): (1) NR (control): basal diet without IAA restriction; (2) R50: basal diet with IAA restricted by 50%; (3) R75: basal diet with IAA restricted by 75%. IAA were alanine (Ala), arginine (Arg), isoleucine (Ile), leucine (Leu), lysine (Lys), threonine (Thr), phenylalanine (Phe), and valine (Val) as suggested by previous studies. Thermal images, body weight, and growth parameters were recorded weekly, oral glucose tolerance tests were performed on week 2 of the study, and blood and tissue samples were collected on week 3 after a meal test. Results: R75 improved glucose tolerance and, together with R50, reduced blood insulin concentration and homeostatic model assessment for insulin resistance (HOMA-IR) value, which is suggestive of improved insulin sensitivity following IAA restriction. R75 increased thermal radiation and decreased adipocyte number in white adipose tissue (WAT). R75 had a greater transcript of glucose transporter 1 (GLUT1), phosphofructokinase, liver type (PFKL), and pyruvate kinase, liver, and RBC (PKLR) in the liver and glucokinase (GCK) in WAT indicating a higher uptake of glucose in the liver and greater glycolysis in both liver and WAT. R75 increased the mRNA abundance of insulin receptor substrate 1 (IRS1) and protein kinase B (AKT1) in skeletal muscle suggestive of enhanced insulin signaling. Further, R75 had a higher mRNA of fibroblast growth factor 21 (FGF-21) in both the liver and hypothalamus and its upstream molecules such as activating transcription factor 4 (ATF4) and inhibin subunit beta E (INHBE) which may contribute to increased energy expenditure and improved glucose tolerance during IAA restriction. Conclusions: IAA restriction improves glucose tolerance and insulin sensitivity in piglets while not reducing body weight, likely through improved hepatic glycolysis and insulin signaling in skeletal muscle, and induced FGF-21 signaling in both the liver and hypothalamus. Full article

Giardiasis is a common intestinal infection caused by Giardia lamblia. The standard treatment for this parasitic infection involves the administration of nitroimidazoles, albendazoles, and nitrothiazoles. However, in recent years, Giardia lamblia strains resistant to these treatments have been reported. Additionally, the current therapies exhibit considerable side effects, highlighting the need for new compounds that specifically target this parasite. The aim of this study was to evaluate nitrothiazole analogs and assess their impact on the metabolic, redox, and structural gene expression of this parasite. First, the compounds CNZ-7, CNZ-8, FLP-2, FLP-6, and FLP-8 were tested at concentrations ranging from 0 to 50 µM to determine their IC₅₀ in G. lamblia cultures. Subsequently, gene expression changes and structural cell damage in trophozoites were analyzed following incubation with the IC₅₀ of each compound. The giardicidal activity of the compounds was also evaluated in a nitazoxanide-resistant strain. The results showed that FLP-2, FLP-6, and FLP-8 exhibited a stronger effect on trophozoite viability compared to nitazoxanide (NTZ) and metronidazole (MTZ). Both compounds induced an increase in the expression of phosphofructokinase (PFK), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), pyruvate kinase (PK), pyruvate phosphate dikinase (PPDK), and pyruvate:ferredoxin oxidoreductase (PFOR). Additionally, FLP-2 caused ultrastructural alterations in trophozoites. Furthermore, FLP-2, FLP-6, and FLP-8 demonstrated efficacy against drug-resistant strains. These findings suggest that FLP-2, FLP-6, and FLP-8 are promising candidates for the treatment of giardiasis, as they effectively reduce parasite viability, modify gene expression, and exhibit activity against drug-resistant G. lamblia strains. Full article

As the source of the first reported class of non-mammalian hemoglobin, Vitreoscilla sp. C1 is a historically important microorganism that has offered important clues to understanding how bacteria can thrive at low oxygen tension, with potential applications to wastewater and sludge bioengineering. However, the processes that enable this bacterium to thrive in such environments remain unclear. In this study, we analyzed the published Vitreoscilla sp. C1 genome to predict the core metabolic pathways used by this microorganism to support cell growth under hypoxic conditions, compared them with the predicted metabolism of other important β-proteobacteria, and tested Vitreoscilla’s respiratory activity in vitro in the presence of various substrates and inhibitors. Vitreoscilla sp. C1 carries a functional Krebs cycle and the genes for a branched aerobic respiratory chain, minus the genes for complexes III and IV, and our results show that Vitreoscilla sp. C1 sugar metabolism is carried out through a unique pathway that shunts intermediaries from glycolysis, bypassing phosphofructokinase-I, into the non-oxidative section of the pentose phosphate pathway, reducing its oxygen dependency, which appears as an adaptation to the microaerophilic environment that this organism inhabits. Although Vitreoscilla sp. C1 features a simplified respiratory chain, experimental data demonstrate that all predicted branches are functional, with two main dehydrogenases and two terminal oxidases. Full article

Background: As a broad-spectrum fluoroquinolone, enrofloxacin (ENR) is commonly employed to manage bacterial infections in aquatic species. Nevertheless, there have been no documented pharmacokinetic and residue studies conducted on Dybowski’s frog (Rana dybowskii). Therefore, the objective of our study was to characterize the pharmacokinetics (PK) of ENR and its metabolite ciprofloxacin (CIP) in R. dybowskii, establish withdrawal times, and evaluate the physiological effects associated with ENR administration. Methods: Adult Rana dybowskii (120 individuals; 60 males and 60 females) were sex-separated and acclimated in four tanks. Prior to dosing, three males and three females were randomly selected as untreated controls (without ENR administration). Following the oral gavage of ENR (10 mg/kg), blood, liver, and kidney tissues were collected at 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 24, 36, 48, and 72 h (n = 6) for pharmacokinetic analysis. Muscle and oviduct tissues were additionally sampled at 1, 3, 7, 15, and 30 days post-dose (n = 6) for ENR content determination. Serum/tissue ENR concentrations were measured via Liquid Chromatography–Tandem Mass Spectrometry (LC-MS/MS) and analyzed using a non-compartmental model (WinNonLin 6.1 software) to calculate PK parameters including peak time (T_max), peak concentration (C_max), and area under the curve (AUC_0−t). In studying the physiology effects of ENR administration, biochemical enzyme activities and gene expressions in the liver and intestine were assessed post-ENR administration. Results: ENR demonstrated rapid absorption and extensive distribution in R. dybowskii. The withdrawal periods were determined to be over 33 days for females and 34 days for males in R. dybowskii. Following ENR administration, there was an increase in immune enzymes (AKP (alkaline phosphatase) and ACP (acid phosphatase)) as well as glycolytic enzymes (HK (hexokinase), PK (pyruvate kinase), PFK (phosphofructokinase)). Antioxidant enzyme levels, specifically SOD (superoxide dismutase) and CAT (catalase), peaked at 1.5 h post-ENR administration but subsequently declined by the 8 h mark. Additionally, following ENR treatment, IGF1, PI3K, and Akt exhibited up-regulation, whereas Keap1 and GYS1 showed down-regulation. Conclusions: The administration of ENR at a dosage of 10 mg/kg significantly enhances the activities of AKP and ACP, promotes glycolysis, and activates the Keap1/Nrf2 and PI3K-Akt signaling pathways in R. dybowskii. These findings establish a foundation for the rational application of ENR and the determination of withdrawal times in frog aquaculture. Full article