Enzymes Of Carbohydrate Metabolism Research Articles

Ferulic acid attenuates streptozotocin induced alternation in glycoprotein moiety via regulation of carbohydrate metabolic enzymes in rats

Ferulic acid attenuates streptozotocin induced alternation in glycoprotein moiety via regulation of carbohydrate metabolic enzymes in rats

Elevated CO2 improves grain yield in bread wheat by enhancing carbon assimilation, activities of carbohydrate metabolic and antixidant enzymes

This study aimed to explore the effects of elevated CO2 (e[CO2]) on wheat performance under drought stress, while investigating the role of eco-physiology, carbohydrate metabolic and antioxidant enzymes to predict the grain yield. Wheat genotype Lianmai6 was grown under ambient (400 ppm) and elevated (800 ppm) CO2 concentrations, with subsequent exposure to drought stress prior to anthesis. Leaf parameters, including photosynthetic rate (An), stomatal conductance (Gs), and transpiration rate (E), were significantly declined under drought. Grain yield parameters were adversely affected by drought stress, while An with water use efficiency (WUE) and yield traits increased under e[CO2]. Notably, the activities of certain carbohydrate metabolic enzymes were increased in sink tissues but reduced significantly in source tissues under drought conditions. However, activities phosphoglucomutase (PGM and phophoglucoisomerase (PGI) were increased in source tissues under the combined effect of drought and e[CO2]. Total antioxidant potential (TAP) decreased in both leaf and spike under drought conditions, yet increased significantly under e[CO2]. These findings suggest that e[CO2] can enhance CO2 assimilation by boosting antioxidant potential and facilitate increased supply of photosynthates through enhanced activities of various carbohydrate metabolic enzymes, ultimately the better grain yield. These findings could elucidate the partial mechanism of better grain yield in bread wheat under combined effect of e[CO2] and drought stress.

The Hepatoprotective Effect of Trigonelline in Diabetic Rat Through Insulin-related IRS1-GLUT2 Pathway: A Biochemical, Molecular, Histopathological, and Immunohistochemical Study

Background: Diabetes significantly increases morbidity and mortality rates, causing complications such as cardiovascular disease, kidney failure, and blindness. Purpose: The aim of this study was to investigate the hepatoprotective effects of trigonelline (TRIG) in diabetic rats through the antioxidative, anti-inflammatory, and insulin-related IRS1-GLUT2 pathway. Methods: In this experimental investigation, sixty male Wistar rats (n = 10/group) were randomly divided into six groups: a healthy group (HEL), healthy rats treated with 1500 and 3000 mg/kg of TRIG, a diabetic (D), and diabetic rats treated with 1500 and 3000 mg/kg of TRIG (D+ TRIG). The effects of TRIG on rats with induced diabetes were evaluated by serum biochemical parameters, such as insulin, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), free fatty acids (FFA), nitric oxide, and adiponectin levels. The activities of hepatic carbohydrate metabolic enzymes (hepatic glucokinase, glucose 6-phosphatase, glycogen, and glucose-6-phosphate dehydrogenase) were also measured. Furthermore, the expression levels of genes and proteins associated with carbohydrate/lipid metabolism, including peroxisome proliferator-activated receptor gamma (PPARg), glucose transporter 2 (GLUT2), insulin receptor substrate 1 (IRS1), sterol regulatory element-binding protein 1c (SREBP-1c) were analyzed using real-time PCR and western blotting techniques, respectively. Liver sections were examined using H&E staining and immunohistochemistry targeting the p53 protein. Results: The results showed that 3000 mg/kg TRIG was able to suppress TNF-α, IL-6, and FFA by inhibiting inflammatory pathways along with increasing the activity of antioxidant enzymes. TRIG treatment regulated serum levels of insulin, adiponectin, and hepatic carbohydrate metabolic enzymes as well as glycogen content by regulation of the IRS1/ GLUT2- SREBP-1c/ PPARg pathway. Conclusion: These results provide evidence that TRIG has the potential to protect liver organs from oxidative damage in diabetic patients.

Ameliorative Histological Effects of Aqueous Neem Leaf Extract (Azadirachta indica) on Lead Induced Neurotoxicity of Lateral Geniculate Body of Adult Wistar Rats

Introduction: Lead exposure remains a significant public health burden across the globe, impacting millions of individuals and posing a major threat to nervous system development and function. Among the vulnerable targets of lead's neurotoxic assault is the lateral geniculate body (LGB), a crucial relay station within the visual pathway. This brain region acts as a gateway for visual information, processing signals from the retina and transmitting them to the visual cortex for interpretation. Aim: This study seeks to investigate the potential neuroprotective effects of aqueous Azadirachta indica (Neem leaf) extract against lead-induced neurotoxicity in the LGN of adult rats. Methods: Twenty (20) adult wistar rats weighing 150-200g were randomly grouped into four(4) (A-D, n=5). Group A Normal control Group B received (70mg/kg)(Orally) Lead only, Group C received (200mg/kg)(Orally) Azadirachta indica (Neem leaf), Group D received (70mg/kg Lead and 200mg/k Azadirachta indica)(Orally). Alterations in the relative weight of the LGB were determined, and antioxidant status was assessed by measuring Superoxide Dismutase (SOD) and catalase (CAT) and Lactate Dehydrogenase (LDH) levels. The effects of neem leaf extract on lactate dehydrogenase were also evaluated. Additionally, histological changes in the cerebellum due to lead exposure were examined using H&E and Cresyl Violet staining. Results: Lead exposure led to alterations in the relative weight of the LGB, SOD and CAT level was significantly (P,<0.005) reduced compared to the control, while the LDH was significantly increased(P.>0.005) and disruptions in lactate dehydrogenase activity. Aqueous neem leaf extract administration showed potential ameliorative effects mitigating these alterations and histological examination revealed ameliorative changes in the LGB associated with lead exposure. The study highlights the potential neuroprotective effects of aqueous neem leaf extract against lead-induced neurotoxicity, emphasizing its role in mitigating oxidative stress and preserving histological integrity in the LGN. Insights into the effects of neem on carbohydrate metabolism enzymes and cerebellar histology contribute to a comprehensive understanding of its therapeutic potential.

Transgenerational Seed Exposure to Elevated CO2 Involves Stress Memory Regulation at Metabolic Levels to Confer Drought Resistance in Wheat.

Drought is the worst environmental stress constraint that inflicts heavy losses to global food production, such as wheat. The metabolic responses of seeds produced overtransgenerational exposure to e[CO2] to recover drought's effects on wheat are still unexplored. Seeds were produced constantly for four generations (F1 to F4) under ambient CO2 (a[CO2], 400 μmol L-1) and elevated CO2 (e[CO2], 800 μmol L-1) concentrations, and then further regrown under natural CO2 conditions to investigate their effects on the stress memory metabolic processes liable for increasing drought resistance in the next generation (F5). At the anthesis stage, plants were subjected to normal (100% FC, field capacity) and drought stress (60% FC) conditions. Under drought stress, plants of transgenerational e[CO2] exposed seeds showed markedly increased superoxide dismutase (16%), catalase (24%), peroxidase (9%), total antioxidants (14%), and proline (35%) levels that helped the plants to sustain normal growth through scavenging of hydrogen peroxide (11%) and malondialdehyde (26%). The carbohydrate metabolic enzymes such as aldolase (36%), phosphoglucomutase (12%), UDP-glucose pyrophosphorylase (25%), vacuolar invertase (33%), glucose-6-phosphate-dehydrogenase (68%), and cell wall invertase (17%) were decreased significantly; however, transgenerational seeds produced under e[CO2] showed a considerable increase in their activities in drought-stressed wheat plants. Moreover, transgenerational e[CO2] exposed seeds under drought stress caused a marked increase in leaf Ψw (15%), chlorophyll a (19%), chlorophyll b (8%), carotenoids (12%), grain spike (16%), hundred grain weight (19%), and grain yield (10%). Hence, transgenerational seeds exposed to e[CO2] upregulate the drought recovery metabolic processes to improve the grain yield of wheat under drought stress conditions.

Ameliorative potential of β-sitosterol and lupeol on high fat diet and streptozotocin -induced hepatorenal and cardiac complications via regulation of carbohydrate metabolic enzymes in diabetic rats

Introductionβ-Sitosterol is a plant-derived compound that shares structural similarities with cholesterol and is used to treat coronary artery disease, prostate cancer, breast cancer, and hypercholesterolemia etc. Lupeol is a natural pentacyclic triterpene, found in a variety of fruits, vegetables, and traditional Chinese medicines like Astragalusmembranaceus and AtractylodesmacrocephalaKoidz. Numerous pharmacological activities of lupeol have been investigated; they include applications as antioxidant, antiviral, antihypertensive, anti-inflammatory and antitumor agents.The current study wasaimed to examine the potential benefits of β-sitosterol and lupeol in reducing pathophysiological complications caused by high fat diet and streptozotocin by regulating the enzymes involved in the metabolism of carbohydrates in diabetic rats as there was no study on this aspect. MethodsMale albino wistar rats were given a high-fat diet for two weeks in order to cause diabetes in them. Following a two-week period, the animals were administered a low dosage of streptozotocin and maintained on an overnight fast. Using commercial diagnostic kits, we assessed plasma glucose and glycated hemoglobin (HbA1C). Plasma insulin level was assayed with the help of an ELISA kit and other assays were made biochemically. ResultsThe homeostatic model of insulin resistance, glucose 6-phosphatase, fructose 1,6-bisphosphatase, and blood glucose levels all significantly increased in the diabetic rats, while plasma insulin, hexokinase, glucose 6-phosphate dehydrogenase, and glycogen content significantly decreased.In addition, the hepatic (aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase) and renal (urea and creatinine) indicators in diabetic rats were raised, and their lipid profiles were disrupted. However, diabetic rats treated with lupeol and β-sitosterol significantly restored all these changed parameters to the levels close to normal. Furthermore, the treatment of lupeol and β sitosterol improved the liver, kidney and heart histology alteration to near normal and prevented the body weight loss. DiscussionBecause of its structural polymorphism, β-sitosterol appeared to be more effective than lupeol in all the parameters investigated and thus these results imply that β sitosterol is a more effective antidiabetic medication than lupeol.

Overview of Ethnobotanical-Pharmacological Studies Carried Out on Medicinal Plants from the Serra da Estrela Natural Park: Focus on Their Antidiabetic Potential.

The Serra da Estrela Natural Park (NPSE) in Portugal stands out as a well-preserved region abundant in medicinal plants, particularly known for their pharmaceutical applications in diabetes prevention and treatment. This comprehensive review explores these plants' botanical diversity, traditional uses, pharmacological applications, and chemical composition. The NPSE boast a rich diversity with 138 medicinal plants across 55 families identified as traditionally and pharmacologically used against diabetes globally. Notably, the Asteraceae and Lamiaceae families are prevalent in antidiabetic applications. In vitro studies have revealed their significant inhibition of carbohydrate-metabolizing enzymes, and certain plant co-products regulate genes involved in carbohydrate metabolism and insulin secretion. In vivo trials have demonstrated antidiabetic effects, including glycaemia regulation, insulin secretion, antioxidant activity, and lipid profile modulation. Medicinal plants in NPSE exhibit various activities beyond antidiabetic, such as antioxidant, anti-inflammatory, antibacterial, anti-cancer, and more. Chemical analyses have identified over fifty compounds like phenolic acids, flavonoids, terpenoids, and polysaccharides responsible for their efficacy against diabetes. These findings underscore the potential of NPSE medicinal plants as antidiabetic candidates, urging further research to develop effective plant-based antidiabetic drugs, beverages, and supplements.

Antidiabetic effect of the mixture of Cissus polyantha and Rytigynia senegalensis in high-fat diet and streptozocin-induced diabetic rats

BackgroundIn traditional Chinese medicine (TCM) practices, many plants of the Cissus and Rytigynia genera are used to treat many diseases including diabetes mellitus.The aim of this study was to evaluate the modulating effects of the mixture of the aqueous extracts of Cissus polyantha and Rytiginia senegalensis (CPRS) on some enzymes of carbohydrate metabolism, oxidative profile, and cardiovascular parameters in diabetic rats. MethodsDiabetes was induced by a diet enriched in high-fat for 30 days associated with a single intraperitoneal injection of streptozocin (35 mg/kg). Rats with a blood glucose level greater than or equal to 200 mg/dL were selected and divided into groups. Groups 1 and 2 received distilled water. Group 3 received metformin (40 mg/kg). Groups 4 and 5 received CPRS at doses of 50 and 111 mg/kg, respectively. Glycaemia, body mass, food and water intake, insulinemia, insulin resistance and insulin secretion indices, lipid profile and cardiovascular risk indices, oxidant profile, glycogen and liver enzymes were evaluated. Histology of the pancreas and heart was performed. ResultsCPRS (50 and/or 111 mg/kg) significantly (p < 0.05 to p < 0.001) reduced water and food consumption, blood glucose, HOMA-IR, coronary risk index, cholesterol, triglyceride, LDL-c, VLDL-c, and malondialdehyde levels, as well as glucose-6-phosphatase and fructose-1,6-biphosphatase activities in diabetic animals. In contrast, CPRS (50 and/or 111 mg/kg) caused an increase (p < 0.05 to p < 0.001) in body mass, insulinemia and HDL-c levels, reduced glutathione and hepatic glycogen. HOMA-β, insulin distribution, atherogenic and cardioprotective indices as well as superoxide dismutase, catalase, glucokinase, and glucose-6-phosphate dehydrogenase activities were also increased after CPRS administration. CPRS regenerated pancreatic islet β cells and decreased leukocyte infiltration in cardiomyocytes of diseased animals. ConclusionCPRS has hypoglycemic, antidyslipidemic, and antioxidant effects, thus validating its use in traditional medicine in the treatment of diabetes mellitus and its complications.

Prophylactic effects of Combretum molle boughs on changes in the hematological, biochemical, and histological parameters in dexamethasone-induced insulin-resistant rats

BackgroundCombretum molle (Combretaceae) is a plant used in Cameroon traditional medicine to treat diabetes mellitus. To our knowledge, no studies have been performed on the preventive effects of C. molle on change in hematological, biochemical, and histological parameters of insulin-resistant rats. The aim of the study was to evaluate the preventive effect of C. molle on changes in the hematological biochemical, and histological parameters of insulin-resistant rats. MethodsInsulin resistance was induced for 10 days by subcutaneous injection of dexamethasone (1 mg/kg), one hour after oral pretreatment of animals with distilled water, metformin (40 mg/kg), and C. molle extract (250 and 500 mg/kg). Hematological profile (red blood cells, white blood cells, platelets and their indices), biomarkers of renal and hepatic function, hepatic glycogen level, activity of hepatic enzymes of carbohydrate metabolism, and histological sections of kidney, liver and pancreas were assessed. ResultsC. molle extract (250 and 500 mg/kg) caused a significant decrease (p < 0.05 to p < 0.001) in white blood cells, platelets count, and the activities of fructose 6-diphosphatase, glucose-6-phosphate dehydrogenase, and transaminases. It also caused significant increase (p < 0.05 to p < 0.001) in red blood cells, hemoglobin, albumin, glycogen, urea, uric acid, and creatinine values, and fructose-1,6-diphospatase and glucokinase activity. Histological examination revealed regeneration of beta-cells of the pancreatic islets and preventive renal and hepatic tissues against damages caused by impact of dexamethasone. ConclusionC. molle extract protected insulin-resistant patients from hematological, biochemical, and histopathological changes, there by validating the merits of the use of this plant in traditional medicine to treat diabetes mellitus and its complications.

Algae-Based Supplements Claiming Weight Loss Properties: Authenticity Control and Scientific-Based Evidence on Their Effectiveness.

The worldwide prevalence of obesity impacts more than 600 million adults. Successfully managing weight is effective in reducing the risk of chronic diseases, but sustaining long-term weight loss remains a challenge. Although there are supplements based on algae that claim to aid in weight loss, there is a notable scarcity of scientific evidence supporting their effectiveness, and their regular consumption safety remains inadequately addressed. In this work, commercially available Arthrospira (Spirulina) platensis Gomont and/or Fucus vesiculosus L. supplements showed moderate capacity to inhibit the activity of carbohydrate-metabolizing enzymes, and to scavenge biologically relevant reactive species. IC25 values varying between 4.54 ± 0.81 and 66.73 ± 5.91 µg of dry extract/mL and between 53.74 ± 8.42 and 1737.96 ± 98.26 µg of dry extract/mL were obtained for α-glucosidase and aldose reductase, respectively. A weaker effect towards α-amylase activity was observed, with a maximum activity of the extracts not going beyond 33%, at the highest concentrations tested. Spirulina extracts showed generally better effects than those from F. vesiculosus. Similar results were observed concerning the antiradical capacity. In a general way, the extracts were able to intercept the in vitro-generated reactive species nitric oxide (•NO) and superoxide anion (O2•-) radicals, with better results for O2•-scavenging with the spirulina samples (IC25 values of 67.16 and 122.84 µg of dry extract/mL). Chemically, similar pigment profiles were observed between spirulina supplements and the authenticated counterpart. However, fucoxanthin, the chemotaxonomic marker of brown seaweeds, was not found in F. vesiculosus samples, pointing to the occurrence of a degradation phenomenon before, during, or after raw material processing. Our findings can contribute to providing data to allow regulatory entities (e.g., EFSA and FDA) to better rule these products in a way that can benefit society.

Antidiabetic Properties of Stingless Bee Pollen in High-Fat Diet FED-Low Dose STZ Induced Experimental T2DM Rats

Diabetes mellitus (DM) is a multisystem metabolic disease because of either insulin insufficiency or ineffectiveness. Individuals with DM continuously measure their blood glucose levels during fasting and after eating in order to manage their condition effectively. glucose levels during fasting and after eating in order to manage their condition effectively. Despite the availability of several drugs, there is no treatment proven to be perfect due to adverse side impacts as well as reduced long-term efficacy. Moreover, the excessive formation of free radicals has been linked to diabetes progression, development, as well as complications. As a result, there is a need to explore new medicines without side effects, preferably derived from natural products. Therefore, this study analyzes the antidiabetic properties of stingless bee pollen scientifically. This natural product was fed a high-fat diet and low streptozotocin doses in experimental rats with T2DM. An oral glucose tolerance test aimed investigate stingless bee pollen effect on glucose homeostasis. An insulin toleration test was executed to obtain stingless pollen influence on insulin sensitivity. This study measures Insulin resistance with HOMA-IR. Oral administration of stingless bee pollen for 30 days raised glucose homeostasis in T2DM rats, as shown by the OGTT, ITT, and HOMA-IR results. In addition, this treatment significantly improved changes in glycated hemoglobin, fasting blood glucose, protein, uric acid, urea, as well as creatinine levels. The activity changes of ALP, AST, and ALT liver enzyme markers in T2DM rats were nearly normalized after given with stingless bee pollen. The activity of carbohydrate metabolism enzymes includes pyruvate kinase, glucokinase, glucose-6-phosphatase, glucose-6-phosphate dehydrogenase, fructose-1,6-bisphosphatase and lactate dehydrogenase in T2DM rats’ liver tissue. This change was significantly restored to near-normal levels after stingless bee pollen treatment.&#x0D; Keywords: Diabetes Mellitus, High Fat Diet, Metformin, Stingless Bee Pollen

5-ALA, DTA-6, and Nitrogen Mitigate NaCl Stress by Promoting Photosynthesis and Carbon Metabolism in Rice Seedlings.

A large number of dead seedlings can occur in saline soils, which seriously affects the large-scale cultivation of rice. This study investigated the effects of plant growth regulators (PGRs) and nitrogen application on seedling growth and salt tolerance (Oryza sativa L.), which is of great significance for agricultural production practices. A conventional rice variety, "Huang Huazhan", was selected for this study. Non-salt stress treatments included 0% NaCl (CK treatment), CK + 0.05 g N/pot (N treatment), CK + 40 mg·L-1 5-aminolevulinic acid (5-ALA) (A treatment), and CK + 30 mg·L-1 diethylaminoethyl acetate (DTA-6) (D treatment). Salt stress treatments included 0.3% NaCl (S treatment), N + 0.3% NaCl (NS treatment), A + 0.3% NaCl (AS treatment), and D + 0.3% NaCl (DS treatment). When 3 leaves and 1 heart emerged from the soil, plants were sprayed with DTA-6 and 5-ALA, followed by the application of 0.3% NaCl (w/w) to the soil after 24 h. Seedling morphology and photosynthetic indices, as well as carbohydrate metabolism and key enzyme activities, were determined for each treatment. Our results showed that N, A, and D treatments promoted seedling growth, photosynthesis, carbohydrate levels, and the activities of key enzymes involved in carbon metabolism when compared to the CK treatment. The A treatment had the most significant effect, with increases in aboveground dry weight and net photosynthetic rates (Pn) ranging from 17.74% to 41.02% and 3.61% to 32.60%, respectively. Stomatal limiting values (Ls) significantly decreased from 19.17% to 43.02%. Salt stress significantly inhibited seedling growth. NS, AS, and DS treatments alleviated the morphological and physiological damage of salt stress on seedlings when compared to the S treatment. The AS treatment was the most effective in improving seedling morphology, promoting photosynthesis, increasing carbohydrate levels, and key enzyme activities. After AS treatment, increases in aboveground dry weight, net photosynthetic rate, soluble sugar content, total sucrose synthase, and amylase activities were 17.50% to 50.79%, 11.39% to 98.10%, 20.20% to 80.85%, 21.21% to 33.53%, and 22.17% to 34.19%, respectively, when compared to the S treatment. In summary, foliar sprays of 5-ALA, DTA-6, and additional nitrogen fertilizer enhanced rice seedling growth, increased photosynthesis, lowered Ls values, and improved seedling salt tolerance. Spraying two regulators, 5-ALA and DTA-6, quantitatively increased the effect of nitrogen fertilizer, with comparable effects on NaCl stress regulation. This study provides the basis for efficient agricultural production.

Characterization of phyllosphere endophytic lactic acid bacteria reveals a potential novel route to enhance silage fermentation quality.

The naturally attached phyllosphere microbiota play a crucial role in plant-derived fermentation, but the structure and function of phyllosphere endophytes remain largely unidentified. Here, we reveal the diversity, specificity, and functionality of phyllosphere endophytes in alfalfa (Medicago sativa L.) through combining typical microbial culture, high-throughput sequencing, and genomic comparative analysis. In comparison to phyllosphere bacteria (PB), the fermentation of alfalfa solely with endophytes (EN) enhances the fermentation characteristics, primarily due to the dominance of specific lactic acid bacteria (LAB) such as Lactiplantibacillus, Weissella, and Pediococcus. The inoculant with selected endophytic LAB strains also enhances the fermentation quality compared to epiphytic LAB treatment. Especially, one key endophytic LAB named Pediococcus pentosaceus EN5 shows enrichment of genes related to the mannose phosphotransferase system (Man-PTS) and carbohydrate-metabolizing enzymes and higher utilization of carbohydrates. Representing phyllosphere, endophytic LAB shows great potential of promoting ensiling and provides a novel direction for developing microbial inoculant.

Comparative physiological, biochemical and proteomic analyses reveal key proteins and crucial regulatory pathways related to drought stress tolerance in faba bean (Vicia faba L.) leaves

Drought is one of the important abiotic factors that affect faba bean growth and productivity in the Mediterranean region. In order to study the response of faba bean plant to water-deficit stress, a physiological and proteomic analysis was carried out in leaf tissue. All physiological parameters were affected by drought. The physiological mechanism underlying the response of faba bean leaves to water-deficit was therefore attributed to the alleviation of oxidative stress via the accumulation of proline and to the synergistic action of the antioxidant enzyme system (CAT, SOD, APX and GPOX). Proteomic analysis identified 2000 proteins from faba bean leaves, of which were 81 differentially expressed. Of those, 36 were downregulated and 45 were upregulated under water-deficit treatment. KEGG and GO enrichments indicated differentially abundant proteins (DAPs) related to photosynthesis, antioxidants and ROS detoxifying enzymes, biosynthesis of amino acids and secondary metabolites, molecular chaperones, signal transduction, energy and carbohydrate metabolism and metabolic enzymes. The current results provide evidence for a complex synergetic pathway, in which ROS detoxification mechanisms and photoprotection constituted the major aspect of water-deficit tolerance in faba bean leaves. These results offer a foundational basis regarding the molecular mechanism involved in drought resistance within the faba bean species.

DFT study of sucrose hydrolysis by a GH32 cell-wall invertase, a key enzyme in carbohydrate metabolism

ABSTRACT The Arabidopsis thaliana cell-wall invertase 1 (AtCWIN1), a member of the family 32 glycoside hydrolase (GH32), hydrolyzes sucrose into fructose and glucose via a retaining mechanism. AtCWIN1 plays a key role in sucrose metabolism in plant. Here, the reaction mechanism of the GH32 AtCWIN1 enzyme has been investigated using quantum chemical approach. Two alternative orientations of an acid/base catalyst (Glu203) with regard to the location of the pK a modulators (Arg148 and Tyr279) are investigated to understand the involvement of these pK a residues in the reaction. The calculations suggested that the orientation involving a hydrogen bond network (Arg148•••Glu203•••Tyr279) is energetically more favourable than the other (Arg148•••Glu203), with a barrier of 17.5 kcal mol−1, which is consistent with the experimental value (15.3 kcal/mol). This Arg148•••Glu203•••Tyr279 interaction provides a strong H-bond network that stabilises the reaction effectively. Overall, this study demonstrates that the enzymatic activity in AtCWIN1 depends on a hydrogen bond network created by the residues Arg148, Glu203, and Tyr279.

The role of abiotic and biotic factors of aged brine in directing microbial assembly and volatile profiles of Paocai during fermentation

Aged brine is a representative natural starter that evolves with stable abiotic and biotic conditions for reproducible quality of fermented vegetables. In this study, the role of aged brine in directing the quality formation of Paocai (a traditional fermented vegetable) was investigated by analyzing the contribution of abiotic and biotic factors to physicochemical properties, volatile compound profiles, microbial composition and function in Paocai. Results showed that the abiotic factors in aged brine promoted reducing sugar consumption and lactic acid accumulation by facilitating the growth of indigenous lactic acid bacteria (LAB) and yeasts. Also, the masking effect of abiotic factors on isothiocyanates and disulfide alleviated the pungent flavor of Paocai. The biotic factors introduced indigenous dominant LAB genera of Liquorilactobacillus, Levilactobacillus, Lactiplantibacillus, Secundilactobacillus, Pediococcus, Lentilactobacillus, Lacticaseibacillus, Lactobacillus and indigenous dominant yeast genera of Kazachstania and Brettanomyces into Paocai. LAB functioned in the production of acid and aldehyde, while yeasts contributed to the accumulation of esters and lactones. Both LAB and yeasts reduced the contents of pungent compounds in Paocai during fermentation. Analysis of microbial function revealed that the role of aged brine was related to the regulation of carbohydrate metabolism and carbohydrate-active enzymes of the microbial community. This study provided an understanding of the role of aged brine in shaping the quality of fermented vegetables.

IMPACT OF MELATONIN ON SOME INDICATORS OF CARBOHYDRATE METABOLISM IN LIVER OF RATS WITH DEXAMETHASONE-INDUCED DIABETES

One frequently employed experimental model, particularly in pre-clinical studies examining the hypoglycemic effects of potential antidiabetic medications, is the metasteroid diabetes model induced by the prolonged administration of glucocorticoids to animals. This experimental study aimed to elucidate the effects of exogenous melatonin (10 mg/kg) on glycogen content and the activity of key enzymes—pyruvate kinase (PK) [EC 2.7.1.40], lactate dehydrogenase (LDH) [EC 1.1.1.27], glucose-6-phosphate dehydrogenase (G-6-PDH) [EC 1.1.1.49], and glucose-6-phosphatase (G-6-P-ase) [EC 3.1.3.9]—in the livers of rats with dexamethasone-induced diabetes. Materials and Methods. The experiments were performed on 44 male 18-month-old white non-linear rats, divided into three groups: 1) control (intact rats), 2) rats with dexamethasone-induced diabetes, 3) rats that amid the progression of dexamethasone-induced diabetes, underwent daily oral administration of melatonin (Sigma, USA) in a dose of 10 mg/kg. Dexamethasone diabetes was modeled by subcutaneous injection of dexamethasone (injection solution 4 mg/ml, KRKA, Slovenia) at a dose of 0.125 mg/kg body weight daily for 13 days (O.V. Stefanov, 2001). Decapitation of animals was carried out in accordance with the norms of the "European Convention for the Protection of Vertebrate Animals Used for Experimental and Other Scientific Purposes" (Strasbourg, 1986). Glucose content in blood from the tail vein of rats, taken on the 14th day of fasting before decapitation of the animals, was determined using a portable glucometer (One Touch Ultra Easy, Life Scan, USA). The content of glycogen and the activity of the studied enzymes of carbohydrate metabolism in the liver were determined according to the generally accepted, previously described methods. A 5% homogenate was prepared from the cold-isolated rat liver in a chilled 50 mM Tris-HCI buffer (pH=7.4) to study the activities of pyruvate kinase, lactate dehydrogenase, glucose-6-phosphate dehydrogenase and glucose-6-phosphatase in the cytosolic fraction. The reliability of the difference between the obtained indicators was assessed using the parametric Student's t-test (for normal distribution) and the non-parametric Mann-Whitney U-test (for non-normal distribution). Differences were considered probable at p≤0.05. Results and discussion. According to our results, in the liver of diabetic rats that did not receive any means of correction of carbohydrate metabolism disorders, the glycogen content was 33% lower than in intact animals. The activities of enzymes such as pyruvate kinase and glucose-6-phosphate dehydrogenase were also reduced in the liver of rats with impaired glucose tolerance by 31.6 and 21.5%, respectively, compared to intact animals, indicating inhibition of glucose oxidation pathways, both at the level glycolysis (decrease of pyruvate kinase), as well as at the level of the oxidative stage of the pentose-phosphate pathway of glucose-6-phosphate oxidation. At the same time, the activity of lactate dehydrogenase and especially glucose-6-phosphatase in the liver of rats with diabetes by 19.5 and 56%, respectively, exceeded the indicators of animals of the control group, which demonstrates the increased activity, intensity of glycogenolysis and gluconeogenesis under conditions of insulin resistance, because glucose-6-phosphatase is the terminal enzyme of these processes. Regarding the investigated parameters of carbohydrate metabolism, both the glucose content in the blood of rats, as well as the glycogen content and the activity of all studied enzymes in the liver of rats that were injected with melatonin against the background of the development of diabetes, did not reliably differ from the parameters of intact animals, which confirms the assumption of the probable hypoglycemic effect of melatonin against the background of the development of diabetes. Conclusions: The daily two-week use of melatonin (10 mg/kg), against the background of the development of dexamethasone diabetes in rats, contributes to the normalization of certain indicators of carbohydrate metabolism in the liver of animals.

1-Deoxynojirimycin Mitigates Glycogen and Carbohydrate Metabolic Enzyme Alterations in High Glucose-Induced Diabetic Tilapia: Implications for Therapeutic Intervention

This study investigated the effects of 1- deoxynojirimycin (DNJ) on blood glucose levels, body weight changes, glycogen levels, and carbohydrate marker enzyme activity in a high glucose-induced experimental diabetic tilapia model. We utilized spectrophotometry assay methods to achieve this objective. DNJ treatment significantly reduced blood glucose and mitigated body weight loss compared to the diabetic control group. Furthermore, DNJ treatment increased glycogen levels in liver and muscle tissues, suggesting its potential to enhance glycogen synthesis or reduce glycogen breakdown. DNJ treatment also modulated the activity of carbohydrate marker enzymes, indicating its possible inhibitory effect on enzymes involved in carbohydrate absorption and breakdown, which in turn may improve glucose homeostasis and control. The results of this study highlight DNJ's potential as a therapeutic agent for diseases associated with glycogen metabolism and glucose homeostasis, as well as its ability to influence body weight changes in diabetic conditions. Our findings contribute to the growing body of research on DNJ as a potential therapeutic agent for illnesses linked to glycogen and underscore its therapeutic potential for future treatments targeting glucose metabolism, glycemic control, and weight management.

Activities of Energy Metabolism Enzymes in Atlantic Salmon Salmo salar L. Smolts and Parr Grown under Different Light Regimens.

Activities of enzymes of energy and carbohydrate metabolism in muscles and the liver were studied in Atlantic salmon Salmo salar L. smolts and parr grown under continuous or natural lighting and different feeding regimens in autumn followed by a short photoperiod in winter. Enzyme activities were found to differ between test and control salmon groups and between parr and smolts sampled at the end of the winter period. Smolts grown under continuous lighting and round-the-clock feeding differed from other groups by having higher cytochrome c oxidase (COX) activity and lower aldolase activity in muscles. Differences in aerobic metabolism in muscles between parr and smolts were found to be the same in all experimental groups, COX and aldolase activities being relatively higher in smolts. The pattern of changes in enzyme activities in the liver from parr to smolts differed between different experimental groups. Based on the results, the photoperiod was assumed to affect the activities of energy metabolism enzymes in salmon juveniles and may eventually affect the completion of smoltification.

Antihyperglycaemic Effect of Tetrahydrocurcumin and Pterostilbene: Effect on Key Metabolic Enzymes of Carbohydrate Metabolism in Streptozotocin Induced Diabetes

This study is to assess the glucose lowering activity of tetrahydrocurcumin (THC) and pterostilbene (PTS), in diabetes induced rats by streptozotocin (STZ) and nicotinamide. Diabetic rats were treated THC (80 mg/kg body weight) and PTS (40 mg/kg body weight) for 45 days, after which activities of hexokinase, glucose-6-phosphate dehydrogenase, glucose-6-phosphatase, fructose-1,6-bisphosphatase, sorbitol dehydrogenase in liver and glycogen content in liver and muscle were assayed. The activities of gluconeogeneic enzymes were significantly increased, whereas the activities of hexokinase, glucose-6-phosphate dehydrogenase and glycogen were significantly decreased in diabetic control rats. Both THC and PTS were able to restore the altered enzyme activities to almost near normal levels. THC was more effective than PTS. Our results indicate that administration of THC and PTS to diabetic animals normalizes blood glucose and causes marked improvement of altered carbohydrate metabolic enzymes during diabetes. The THC administration showed more effective than PTS and metformin.