Enzymes Of Carbohydrate Metabolism Research Articles

Attenuation of carbohydrate metabolism and lipid profile by methanolic extract of Euphorbia helioscopia and improvement of beta cell function in a type 2 diabetic rat model

BackgroundTraditional plant-based remedies prescribed to treat diabetes have shown promise in research-based setting. Current research was conducted to examine the antidiabetic and antioxidant effects of methanolic extract of a folk herbal plant Euphorbia helioscopia in a rat model of type 2 diabetes.MethodsDiabetes was induced in male Wistar rats by administering 5% sucrose in drinking water and cafeteria diet for 8 weeks with subsequent nicotinamide and streptozotocin administration. Diabetic rats were then distributed into four individual groups (n = 8); Positive control (PC; no treatment), standard control (SC; Metformin @ 10 mg/kg bw), treatment 1 (EH1, E. helioscopia methanolic extract @200 mg/kg bw) and treatment 2 (EH2, E. helioscopia methanolic extract @400 mg/kg bw). After 21 days of treatments, the rats were decapitated for blood collection. Serum was evaluated for antidiabetic potential, antioxidant and lipid profile, thyroid hormone, amylin, leptin, and carbohydrate metabolic enzymes. Data were analyzed statistically by one-way analysis of variance (ANOVA).ResultsSerum levels of glucagon, glucose and C-peptide were significantly (P ≤ 0.05) decreased in EH1 (1915.33 ± 98.26a pg/ml, 122.59 ± 2.99a mg/dl, 277.59 ± 28.41a pg/ml respectively) and EH2 (1575.28 ± 56.46a pg/ml, 106.04 ± 5.21a mg/dl, 395.06 ± 42.55a pg/ml respectively) as compared to the PC (3135.78 ± 189.46bpg/ml, 191.24 ± 17.75bmg/dl, 671.70 ± 109.75b pg/ml respectively) group. A similar trend was observed in serum insulin levels in EH1 and EH2 groups. The plant’s methanolic extract effectively reduced the total oxidant status (TOS) and MDA levels in the diabetic rats and increased the total antioxidant capacity (TAC) along with an increased level of SOD, Catalase, Paraoxonase, and arylesterase. The plant extract also induced antihyperlipidemic activity and recovered the thyroid hormones, amylin, and leptin levels to normal. The activity of different carbohydrate metabolic enzymes like Pyruvate Kinase, Glucose 6 phosphate dehydrogenase, phosphofructokinase, and glucokinase has also been restored by the extract treatment.ConclusionCurrent study indicates the antioxidant and antidiabetic potential of E. helioscopia methanolic extract in normalizing the lipid profile, thyroid hormones, amylin, leptin, and carbohydrate metabolism in type 2 diabetic rat model.

Exogenously-Sourced Ethylene Positively Modulates Photosynthesis, Carbohydrate Metabolism, and Antioxidant Defense to Enhance Heat Tolerance in Rice.

The effect of exogenously-applied ethylene sourced from ethephon (2-chloroethyl phosphonic acid)was studied on photosynthesis, carbohydrate metabolism, and high-temperature stress tolerance in Taipei-309 and Rasi cultivars of rice (Oryza sativa L.). Heat stress increased the content of H2O2 and thiobarbituric acid reactive substances (TBARS)more in Rasi than Taipei-309. Further, a significant decline in sucrose, starch, and carbohydrate metabolism enzyme activity and photosynthesis was also observed in response to heat stress. The application of ethephon reduced H2O2 and TBARS content by enhancing the enzymatic antioxidant defense system and improved carbohydrate metabolism, photosynthesis, and growth more conspicuously in Taipei-309 under heat stress. The ethephon application enhanced photosynthesis by up-regulating the psbA and psbB genes of photosystem II in heat-stressed plants. Interestingly, foliar application of ethephoneffectively down-regulated high-temperature-stress-induced elevated ethylene biosynthesis gene expression. Overall, ethephon application optimized ethylene levels under high-temperature stress to regulate the antioxidant enzymatic system and carbohydrate metabolism, reducing the adverse effects on photosynthesis. These findings suggest that ethylene regulates photosynthesis via carbohydrate metabolism and the antioxidant system, thereby influencing high-temperature stress tolerance in rice.

Antidiabetic effects of nerolidol through promoting insulin receptor signaling in high-fat diet and low dose streptozotocin-induced type 2 diabetic rats.

The present study was designed to investigate the antidiabetic effect of nerolidol on high-fat diet and streptozotocin-induced diabetic rats. Type 2 diabetes was induced in animals by feeding them a high-fat diet for 4weeks and administering a single intraperitoneal dose of streptozotocin (35mg/kg body weight). Diabetic rats were treated with nerolidol (25mg/kg BW) for 28days. Results showed that nerolidol treatment significantly reduced (p < 0.05) the level of elevated glucose, glycosylated hemoglobin and improved (p < 0.05) the body weight and insulin level. Nerolidol also considerably improved (p < 0.05) the carbohydrate metabolic enzyme activities and increased the glycogen storage in the liver of diabetic rats. Increased serum triglycerides, total cholesterol (C), low-density lipoproteins-C and very low-density lipoproteins-C levels were significantly lowered (p < 0.05), while reduction of serum high-density lipoprotein-C was alleviated after administration of nerolidol. In addition, nerolidol attenuated oxidative stress markers by significantly increasing (p < 0.05) the levels of superoxide dismutase, catalase, reduced glutathione, and lowering (p < 0.05) the level of thiobarbituric acid reactive substances, and lipid hydroperoxide. Similarly, nerolidol showed its pharmacological effects against hepatic markers via restoring (p < 0.05) the alleviated level of alanine transaminase, aspartate aminotransferase, and alkaline phosphatase. Finally, it improved insulin-dependent glucose transport in skeletal muscle by enhancing and activating glucose transporter protein-4. These findings confirmed the antidiabetic potential of nerolidol in type 2 diabetic rats. This may be related to a high antioxidant capacity, the restoration of plasma insulin and lipid levels, and the activation of insulin signaling in STZ/HFD-induced diabetic rats.

Methanolic Extract of Myrsine africana Leaf Ameliorates Hyperglycemia and Dyslipidemia in Alloxan-Induced Diabetic Albino Mice.

Background Diabetes mellitus is one of the leading public health problems globally, and its prevalence is increasing in Ethiopia. The current drugs for people with diabetes are costly, less effective, and less safe with a challenging administration method. Thus, globally, the need for alternative herbal antidiabetic medicines is increasing. In the previous studies, antioxidant activities have been seen in crude extracts of M. africana leaves, which is an auspicious sign of antidiabetic property. Accordingly, this study has evaluated the antidiabetic and antidyslipidemic activities of methanolic extract of M. africana leaves. Methods Hypoglycemic and antihyperglycemic activities of the three doses (250 mg/kg, 500 mg/kg, and 1000 mg/kg) of crude methanolic extract of M. africana leaf were studied on normoglycemic, oral glucose-loaded, and alloxan-induced diabetic mice models. The effect of the extract on diabetic dyslipidemia, insulin and glycated hemoglobin levels, carbohydrate-metabolizing enzymes, and body weight was also studied in alloxan-induced diabetic mice. Glibenclamide (5 mg/kg) was used as a standard drug in all cases. Data analysis was carried out using mixed-design ANOVA. A P value of ≤0.05 was considered a statistically significant difference. Results The methanolic extract of M. africana leaf did not show acute toxicity up to the dose of 5000 mg/kg and showed better glucose utilization in the oral glucose tolerance test. After 14 days of treatment, M. africana leaf extract decreased the blood glucose level, glycated hemoglobin, glucose-6-phosphatase, and fructose-1-6-bisphosphatase in diabetic mice. In contrast, it increased hexokinase and insulin levels in diabetic mice. Moreover, weight loss and dyslipidemia profiles have been corrected significantly in diabetic mice. Conclusion M. africana leaves showed antihyperglycemic and antidyslipidemic effects in alloxan-induced diabetic mice. That suggests M. africana may be a potential treatment option for diabetes in the future. However, further molecular studies are required to analyze the mechanisms.

Anti- hyperglycemic activity of polyherbal formulation (Herbinsulplus) in experimental diabetes and its effects on key metabolic enzymes of carbohydrate metabolism

Diabetes mellitus is a metabolic disorder in which the body does not produce or properly utilize insulin, causes disturbances in carbohydrate, protein and lipid metabolism. In spite of the presence of series of known anti-diabetic medicine in the pharmaceutical market, remedies from medicinal plants are used with success to treat this disease. The investigation was undertaken to study the effect of polyherbal formulation on changes in Body weight, Plasma glucose, RBC, WBC, HB, Platelets, Hepatic glucokinase &amp; hexokinase, Glucose-6-phosphate and Glycogen content. In the current study, diabetes mellitus was induced by alloxan monohydrate at a dose of 150 mg/kg i.p to rats. A significant increase was observed in plasma glucose level in alloxan induced diabetic rats, whereas treatment with Glipizide (10mg/kg), polyherbal formulation (herbinsulplus) at two different doses (120mg/kg and 240mg/kg) showed significant antihyperglycemic activity in mild hyperglycemia. The administration of polyherbal formulation (herbinsulplus) at two doses showed an increase in body weight in alloxan-induced diabetic rats. Treatment with polyherbal formulation (herbinsul plus) at two doses prevented this alteration in glycogen content of liver tissue, but could not normalize the content of glycogen of the non-diabetic control. The groups treated with polyherbal formulation (herbinsul plus) (120mg/kg and 240mg/kg) and Glipizide (10mg/kg) showed greater persistence of islets of Langerhans and lesser degree of necrotic changes as compared to the untreated alloxan-induced diabetic rats. In conclusion, HerbinsulPlus exhibited significant anti-hyperglycemic activity in normal and alloxan induced diabetic rats and showed improvement in carbohydrate metabolizing enzymes as well as regeneration of β-cells of pancreas and so might be of value in diabetes treatment.

EFFECT OF OLIGOSACCHARIDES ON ENZYMES OF CARBOHYDRATE METABOLISM AND ANTIOXIDANT PROTECTION IN IN VITRO TREATED ERYTHROCYTES UNDER CONDITIONS OF HYPERGLYCEMIA

Introduction: The purpose of this experiment is to examine the effect of different oligosaccharides with proven prebiotic effects on enzymes of carbohydrate metabolism and the antioxidant protection of erythrocytes in vitro under conditions of hyperglycemia. Materials and methods: This experiment included 10 healthy men (27±3 years of age). The isolated erythrocytes were treated with 1% and 5% solutions of the following oligosaccharides: lactulose, inulin, galactooligosaccharide and fructooligosaccharide in the presence of 5mM, 50mM and 100mM glucose. After incubation, for 2 hours at 37 °C, the erythrocytes were lysed, and the supernatant was used for analyses of lactate dehydrogenase, hexokinase and glutathione reductase. FRAP (Ferric reducing antioxidant power) method was used for determining the total antioxidant activity of erythrocytes. Results: Lactate dehydrogenase was decreased in the presence of 5% lactulose in groups with 50mM and 100 mM Glc. An increase in the activity of glutathione reductase under severe hyperglycemia (100mM glucose) was observed after treatment with: 1% lactulose, 1% inulin, 1% galactooligosaccharide, 1% and 5% fructooligosaccharides (p&lt;0.005). A significant difference in the enzymatic activity of hexokinase was found in all groups (p&lt;0.05) and of glutathione reductase only in the control group as well as in the groups treated with 1% lactulose, 1% galactooligosaccharide, 1% and 5% fructooligosaccharides Conclusions: Galactooligosaccharides 1% and fructooligosaccharides 1% and 5% cause a statistically significant increase of the enzymatic activities of hexokinase and glutathione reductase in in vitro hyperglycemia induced by 100 mM glucose, as well as an increase in FRAP.

Label-free proteomic analysis reveals freshness-related proteins in sea bass (Lateolabrax japonicus) fillets stored on ice

The advantages of epigallocatechin gallate incorporated in agar oligosaccharide treatment during post-mortem storage on ice for maintaining the quality and proteome stability of sea bass muscle was investigated using hardness, total volatile basic nitrogen, total viable counts, protein biochemical properties and label-free proteomic analysis. The results indicated that hardness value and sulfhydryl content of EGCG–AO-treated fish muscle were much higher than those of the samples immersed in sterile water. The total volatile basic nitrogen, total viable counts, and carbonyl content increased to 165.65%, 18.93%, and 42.37%, respectively after 8 days of storage. Proteomic analysis of muscle samples from control fillets on days 0 (CK0) and 8 (CK8), and EGCG–AO-treated fillets on day 8 (T8) revealed 708 different abundant proteins (DAPs). DAPs in CK8 vs. CK0 fillets were mainly structural proteins, metabolic enzymes, and proteins involved in protein turnover, and were closely related with freshness properties. Muscles from fillets in T8 showed delayed degradation of structural proteins, lower abundance of calpain and carbohydrate metabolic enzymes, and maintained higher levels of transcription and translation to maintain quality. Thus, EGCG–AO treatment is a possible method for maintaining freshness of sea bass fillets. Several DAPs are potential proteomic markers for monitoring fillet freshness.

Effect of sakuranin on carbohydrate-metabolizing enzyme activity modifications in streptozotocin-nicotinamide-induced diabetic wistar rats

This study is to assess the glucose lowering activity of sakuranin in diabetes induced rats by streptozotocin (STZ) and nicotinamide (NA). Diabetic rats were treated sakuranin for 45 days (20, 40, 80 mg/kg) by orally. Sakuranin (80 mg/kg body weight) was normalized the changes of abnormal blood glucose plasma glucose and plasma insulin levels. Hence, we have continued the further research with this active dose of 80 mg/kg sakuranin. The plasma glucose and glycosylated hemoglobin (HbA1c) reduced and insulin, glycogen and hemoglobin levels increased by Sakuranin administration in diabetic rats. Additionally, hexokinase and glucose-6-phophate dehydrogenase activities increased and glucose-6-phosphatase and fructose-1,6-bisphosphatase activities decreased in diabetic condition while administration of treated compound. In this observed result signified that sakuranin may have potential role of diabetic condition rats by evidenced with reducing glucose and increasing insulin and also protect the carbohydrate metabolic changes.

Inoculation of tomato (Solanum lycopersicum) roots with growth promoting Pseudomonas strains induces distinct local and systemic metabolic biosignatures

The genus Pseudomonas harbours numerous strains that positively affect plant growth and defence through diverse mechanisms such as nutrient solubilisation and production of phytohormones or secondary metabolites. The aim of this study was to compare the impact of six plant-beneficial Pseudomonas strains on tomato (Solanum lycopersicum) growth and holobiont physiology. The physiological impact was determined by profiling the activities of key enzymes in the central carbohydrate and antioxidant metabolism. Root inoculation of tomato seedlings with Pseudomonas strains in a greenhouse experiment induced plant growth, measured as biomass and plant height promotion. The bacterial strains also increased leaf chlorophyll content and caused distinct carbohydrate and antioxidative metabolism enzyme activity profiles in leaf and root tissue respectively. For the carbohydrate metabolism, the activities of several key enzymes involved in assimilate partitioning from source to sink and processing of the transport sugar sucrose for catabolism and anabolism were stimulated. For the antioxidative metabolism, both enzymes involved in detoxification of reactive oxygen species and redox buffering were increased. These increased enzyme activities in response to bacterial inoculation could contribute to balancing plant growth and defence. Importantly, positive correlations between plant growth parameters and distinct enzyme activities suggest that host plant biosignatures may be predicting bacteria with plant growth-promoting potential. These findings offer new perspectives for integrating physiological fingerprinting in the screening of microbes during early developmental stages of the host plant. In addition, determining plant metabolic biosignatures could be a rapid tool for predicting the potential and improvement of stress resiliency.

Novel Triterpenoids from Cassia fistula Stem Bark Depreciates STZ-Induced Detrimental Changes in IRS-1/Akt-Mediated Insulin Signaling Mechanisms in Type-1 Diabetic Rats.

Here, we identified the mechanisms of action of antidiabetic activity of novel compounds isolated from Cassia fistula stem bark in STZ-diabetic animals. Novel triterpenoid compounds (C1, C2 and C3) were treated to STZ-administered diabetic animals at a concentration of 20mg/kg body weight orally for 60 days to assess their effects on plasma glucose, plasma insulin/C-peptide, serum lipid markers and the enzymes of carbohydrate metabolism, glucose oxidation and insulin signaling molecules. Oral administration of novel triterpenoid compounds to STZ-diabetic animals significantly decreased (p < 0.05) the plasma glucose concentration on the 7th, 15th, 30th, 45th and 60th daysin a duration-dependent manner (p < 0.05). Plasma insulin (p < 0.0001)/C-peptide (p < 0.0006), tissue glycogen (p < 0.0034), glycogen phosphorylase (p < 0.005), glucose 6-phosphatase (p < 0.0001) and lipid markers were significantly increased (p < 0.0001) in diabetic rats, whereas glucokinase (p < 0.0047), glycogen synthase (p < 0.003), glucose oxidation (p < 0.001), GLUT4 mRNA (p < 0.0463), GLUT4 protein (p < 0.0475) and the insulin-signaling molecules IR mRNA (p < 0.0195), IR protein (p < 0.0001), IRS-1 mRNA (p < 0.0478), p-IRS-1Tyr612 (p < 0.0185), Akt mRNA (p < 0.0394), p–AktSer473 (p < 0.0162), GLUT4 mRNA (p < 0.0463) and GLUT4 (p < 0.0475) were decreased in the gastrocnemius muscle. In silico analysis of C1–C3 with IRK and PPAR-γ protein coincided with in vivo findings. C1–C3 possessed promising antidiabetic activity by regulating insulin signaling mechanisms and carbohydrate metabolic enzymes.

Relationship of Carbohydrate Metabolism and Molecular Genetic Markers in Gliomas with Different Degree of Anaplasia.

We examined postoperative material from 28 patients aged 39-61 years with gliomas of different degrees of anaplasia (the diagnosis was histologically verified according to the WHO classification of CNS tumors) who had not previously received antitumor treatment. In glioma tissue, the glucose concentration was significantly higher than in the brain tissue of subjects dead from traumas (control), while lactate concentration did not differ from that in the control group or was lower. Hexokinase activity demonstrated a tendency to an increase in grade I and significant elevation in grades II and III, while in grade IV gliomas, this parameter did not differ from the control. Activities of the pentose-phosphate pathway enzymes glucose-6-phosphate dehydrogenase and transketolase increased with increasing of tumor anaplasia. Activity of glycogen synthase 3β kinase was significantly higher than in the control group. IDH1 mutation was discovered in 40% cases, the MGMT promoter methylation was detected in more than 50%, the Ki-67 level increased with increasing tumor anaplasia. The most significant correlations with glioma markers were detected for glucose-6-phosphate dehydrogenase and glycogen synthase 3β kinase. Activities of the studied enzymes of carbohydrate metabolism significantly correlated with Ki-67 marker.

Glycogen Storage Disease Type Ia: Current Management Options, Burden and Unmet Needs.

Glycogen storage disease type Ia (GSDIa) is caused by defective glucose-6-phosphatase, a key enzyme in carbohydrate metabolism. Affected individuals cannot release glucose during fasting and accumulate excess glycogen and fat in the liver and kidney, putting them at risk of severe hypoglycaemia and secondary metabolic perturbations. Good glycaemic/metabolic control through strict dietary treatment and regular doses of uncooked cornstarch (UCCS) is essential for preventing hypoglycaemia and long-term complications. Dietary treatment has improved the prognosis for patients with GSDIa; however, the disease itself, its management and monitoring have significant physical, psychological and psychosocial burden on individuals and parents/caregivers. Hypoglycaemia risk persists if a single dose of UCCS is delayed/missed or in cases of gastrointestinal intolerance. UCCS therapy is imprecise, does not treat the cause of disease, may trigger secondary metabolic manifestations and may not prevent long-term complications. We review the importance of and challenges associated with achieving good glycaemic/metabolic control in individuals with GSDIa and how this should be balanced with age-specific psychosocial development towards independence, management of anxiety and preservation of quality of life (QoL). The unmet need for treatment strategies that address the cause of disease, restore glucose homeostasis, reduce the risk of hypoglycaemia/secondary metabolic perturbations and improve QoL is also discussed.

Multi-omics based strategy for toxicity analysis of acrylamide in Saccharomyces cerevisiae model

Although the toxicity of acrylamide (ACR) has been extensively investigated in different experimental models, its perturbations to multiple nodes of the cellular signaling network have not been systematically associated. In this study, changes at different omics layers in ACR exposed Saccharomyces cerevisiae cells were monitored using a multi-omics strategy. The results of the analysis highlighted the impairment of oxidative-reductive balance, energy metabolism, lipid metabolism, nucleotide metabolism, and ribosome function in yeast cells. Response to acute ACR damage, glutathione synthesis was upregulated, the process of protein degradation was accelerated, and the autophagy flux was initiated. Meanwhile, yeast upregulates gene expression levels of enzymes in carbohydrate metabolism and speeds up the oxidation process of fatty acids to compensate for energy depletion. Importantly, the multi-omics strategy captures features that have rarely been addressed in previous studies on the toxicology of ACR, including blocked de novo nucleotide synthesis, decreased levels of metabolic enzyme cofactors thiamine and D-biotin, increased intracellular concentrations of neurotoxic N-methyl d-aspartic acid and l-glutamic acid, and release of death mediators ceramide. The ACR perturbation network constructed in this work and the discovery of new damage features provide a theoretical basis for subsequent point-to-point toxicological studies.

Identification of a bio-signature for barley resistance against Pyrenophora teres infection based on physiological, molecular and sensor-based phenotyping

Necrotic and chlorotic symptoms induced during Pyrenophora teres infection in barley leaves indicate a compatible interaction that allows the hemi-biotrophic fungus Pyrenophora teres to colonise the host. However, it is unexplored how this fungus affects the physiological responses of resistant and susceptible cultivars during infection. To assess the degree of resistance in four different cultivars, we quantified visible symptoms and fungal DNA and performed expression analyses of genes involved in plant defence and ROS scavenging. To obtain insight into the interaction between fungus and host, we determined the activity of 19 key enzymes of carbohydrate and antioxidant metabolism. The pathogen impact was also phenotyped non-invasively by sensor-based multireflectance and –fluorescence imaging.Symptoms, regulation of stress-related genes and pathogen DNA content distinguished the cultivar Guld as being resistant. Severity of net blotch symptoms was also strongly correlated with the dynamics of enzyme activities already within the first day of infection. In contrast to the resistant cultivar, the three susceptible cultivars showed a higher reflectance over seven spectral bands and higher fluorescence intensities at specific excitation wavelengths. The combination of semi high-throughput physiological and molecular analyses with non-invasive phenotyping enabled the identification of bio-signatures that discriminates the resistant from susceptible cultivars.

Chebulagic acid attenuates HFD/streptozotocin induced impaired glucose metabolism and insulin resistance via up regulations of PPAR γ and GLUT 4 in type 2 diabetic rats

The aim of the present study was to evaluate the effects of chebulagic acid on enzymes involved in carbohydrate metabolism in high-fat diet/streptozotocin-induced diabetic rats. Diabetes was induced in albino male Wistar rats by feeding them with a high-fat diet comprising of 84.3% standard laboratory rat chow, 5% lard, 10% yolk powder, 0.2% cholesterol, and 5% bile salt for 2 weeks. After 2 weeks, the animals were kept in an overnight fast and injected with a low dose of streptozotocin (35 mg/kg, dissolved in 0.1 M sodium citrate buffer, pH 4.5). At the end of the experimental periods, the blood glucose, plasma insulin, hemoglobin, glycated hemoglobin levels, homeostatic model of insulin resistance, glycogen content, glycogen synthase, glycogen phosphorylase were measured in high-fat diet and streptozotocin-induced diabetic rats whereas the glucose metabolic enzymes such as hexokinase, glucose 6 phosphate dehydrogenase, glucose 6 phosphatase, fructose 1,6 bisphosphatase and protein expression of peroxisome proliferator-activated receptor–γ (PPAR-γ) and Glucose transporter 4 (GLUT4) were analyzed. Administration of chebulagic acid to HFD/STZ -induced diabetic rats for 30 days significantly decreased the levels of plasma glucose, homeostatic model assessment of insulin resistance, glycogen phosphorylase and glycosylated hemoglobin and increased the levels of insulin, glycogen content and glycogen synthase. On the other hand, the altered activity of carbohydrate metabolic enzymes, PPAR-γ and GLUT4 were brought back to near-normal levels on treatment with chebulagic acid. The effect produced by chebulagic acid on various parameters was comparable to that of metformin.

Activity of Energy and Carbohydrate Metabolism Enzymes in the Juvenile Pink Salmon Oncorhynchus gorbuscha (Walb.) during the Transition from Freshwater to a Marine Environment

Biochemical adaptations of energy metabolism and some pathways of glucose oxidation during a change in salinity of the environment in larvae and smolts of the pink salmon Oncorhynchus gorbuscha (Walb.) inhabiting the White Sea were studied. We assayed the activity of energy and carbohydrate metabolism enzymes (cytochrome c oxidase (COХ), lactate dehydrogenase (LDH), glucose-6-phosphate dehydrogenase (G6PDH), 1-glycerophosphate dehydrogenase (1-GPDH), and aldolase) in pink salmon larvae in a short-term aquarium experiment and in pink salmon smolts in a long-term cage experiment simulating the transition of juveniles from freshwater to a marine environment. A decrease in the activity of COX, LDH, 1‑GPDH, and aldolase already in the first hour after the transfer of larvae to seawater was shown. Smolts kept in the estuary and in the sea had low levels of activity of 1-GPDH and aldolase in comparison with individuals from the river. Most likely, in the salmon juveniles studied, there was a redistribution of carbohydrates between the reactions of aerobic and anaerobic metabolism in favor of anaerobic ATP synthesis. No changes in the enzyme activity of the pentose phosphate pathway, G-6-PDH, were found in either larvae or smolts compared with the individuals kept in freshwater. Maintenance of the required levels of anaerobic metabolism and of the pentose phosphate pathway is probably one of the mechanisms of biochemical adaptation of pink salmon to changes in salinity.

The Crosstalk of Melatonin and Hydrogen Sulfide Determines Photosynthetic Performance by Regulation of Carbohydrate Metabolism in Wheat under Heat Stress.

Photosynthesis is a pivotal process that determines the synthesis of carbohydrates required for sustaining growth under normal or stress situation. Stress exposure reduces the photosynthetic potential owing to the excess synthesis of reactive oxygen species that disturb the proper functioning of photosynthetic apparatus. This decreased photosynthesis is associated with disturbances in carbohydrate metabolism resulting in reduced growth under stress. We evaluated the importance of melatonin in reducing heat stress-induced severity in wheat (Triticum aestivum L.) plants. The plants were subjected to 25 °C (optimum temperature) or 40 °C (heat stress) for 15 days at 6 h time duration and then developed the plants for 30 days. Heat stress led to oxidative stress with increased production of thiobarbituric acid reactive substances (TBARS) and hydrogen peroxide (H2O2) content and reduced accrual of total soluble sugars, starch and carbohydrate metabolism enzymes which were reflected in reduced photosynthesis. Application of melatonin not only reduced oxidative stress through lowering TBARS and H2O2 content, augmenting the activity of antioxidative enzymes but also increased the photosynthesis in plant and carbohydrate metabolism that was needed to provide energy and carbon skeleton to the developing plant under stress. However, the increase in these parameters with melatonin was mediated via hydrogen sulfide (H2S), as the inhibition of H2S by hypotaurine (HT; H2S scavenger) reversed the ameliorative effect of melatonin. This suggests a crosstalk of melatonin and H2S in protecting heat stress-induced photosynthetic inhibition via regulation of carbohydrate metabolism.

Right versus left ventricular remodeling in heart failure due to chronic volume overload

Mechanisms of right ventricular (RV) dysfunction in heart failure (HF) are poorly understood. RV response to volume overload (VO), a common contributing factor to HF, is rarely studied. The goal was to identify interventricular differences in response to chronic VO. Rats underwent aorto-caval fistula (ACF)/sham operation to induce VO. After 24 weeks, RV and left ventricular (LV) functions, gene expression and proteomics were studied. ACF led to biventricular dilatation, systolic dysfunction and hypertrophy affecting relatively more RV. Increased RV afterload contributed to larger RV stroke work increment compared to LV. Both ACF ventricles displayed upregulation of genes of myocardial stress and metabolism. Most proteins reacted to VO in a similar direction in both ventricles, yet the expression changes were more pronounced in RV (pslope: < 0.001). The most upregulated were extracellular matrix (POSTN, NRAP, TGM2, CKAP4), cell adhesion (NCAM, NRAP, XIRP2) and cytoskeletal proteins (FHL1, CSRP3) and enzymes of carbohydrate (PKM) or norepinephrine (MAOA) metabolism. Downregulated were MYH6 and FAO enzymes. Therefore, when exposed to identical VO, both ventricles display similar upregulation of stress and metabolic markers. Relatively larger response of ACF RV compared to the LV may be caused by concomitant pulmonary hypertension. No evidence supports RV chamber-specific regulation of protein expression in response to VO.

Aloe vera carbohydrates regulate glucose metabolism through improved glycogen synthesis and downregulation of hepatic gluconeogenesis in diabetic rats

Ethnopharmacological relevanceAloe vera (L.) Burm.f. is an ancient medicinal plant that belongs to the family Asphodelaceae. It has a rich source of bioactive constituents such as carbohydrates, polyphenols, peptides, sterols and tannins, etc. Aloe vera has multiple biological activities such as anti-inflammatory, antioxidant and antidiabetic activity etc. Aim of the studyThe present study investigated the antidiabetic mechanism of Aloe vera carbohydrate fraction (AVCF) and aimed to provide insights into the regulation of carbohydrate metabolism enzymes in glucose homeostasis. Materials and methodsThe antidiabetic effect of AVCF was evaluated using α-amylase, α-glucosidase inhibition, glucose diffusion and glucose uptake assay. The in vitro AVCF effect on insulin secretion, cell proliferation and inflammatory markers were determined using streptozotocin-induced oxidative stress on RIN-m5F cells. Streptozotocin-induced male Wistar diabetic rats were treated for 21 days with AVCF (54 mg/kg bw). The in vivo AVCF effect was measured on fasting plasma glucose, insulin, glucagon, hexokinase, glycogen synthase and glucose-6-phosphatase, levels in diabetic rats. Histopathological studies for organ-specific effects in the pancreas, liver and small intestine were also conducted. ResultsAVCF-treated RIN-m5F cells significantly increased BrdU levels, with insulin secretion, and decreased TNF-α, IL-6 and nitric oxide levels. AVCF treated streptozotocin-induced diabetic rats showed significantly decreased fasting plasma glucose, glucagon and glucose-6-phosphatase levels with a concomitant increase in insulin, hexokinase, and glycogen synthase levels and, glycogen content. These findings corroborate with the improved hepatic glycogen content in the PAS stained histological section of the liver of AVCF treated diabetic rats. ConclusionThese results suggest that CF of Aloe vera improved glucose metabolism by activation of glycogenesis and down-regulation of gluconeogenesis thereby, maintaining glucose homeostasis. Hence, AVCF can be used as an alternative medicine in the alleviation of diabetes mellitus symptoms.

Effects of the Carbohydrate Sources Nectar, Sucrose and Invert Sugar on Antibacterial Activity of Honey and Bee-Processed Syrups.

Honey is a functional food with health-promoting properties. Some types of honey are used in wound care for the treatment of acute and chronic infected wounds. Increased interest in using honey as a functional food and as a base for wound care products causes limited availability of raw honey. Numerous studies suggest that the protein content of honey is mainly comprised of bee-derived proteins and peptides, with a pronounced antibacterial effect. Therefore, the aim of our study was to characterize for the first time the antibacterial activity of raw honeys and bee-processed syrups which were made by processing sucrose solution or invert sugar syrup in bee colonies under field conditions. Furthermore, we compared the contents of glucose oxidase (GOX) and the levels of hydrogen peroxide (H2O2) in honey samples and bee-processed syrups. These parameters were also compared between the processed sucrose solution and the processed invert sugar syrup. Our results clearly show that natural honey samples possess significantly higher antibacterial activity compared to bee-processed syrups. However, no differences in GOX contents and accumulated levels of H2O2 were found between honeys and bee-processed syrups. Comparison of the same parameters between bee-processed feeds based on the two artificial carbohydrate sources revealed no differences in all measured parameters, except for the content of GOX. The amount of GOX was significantly higher in bee-processed sucrose solutions, suggesting that processor bees can secrete a higher portion of carbohydrate metabolism enzymes. Determination of honey color intensity showed that in bee colonies, bee-processed syrups were partially mixed with natural honey. Further research is needed to identify the key botanical compounds in honey responsible for the increased antibacterial potential of honey.