Metabolic Enzyme Activities Research Articles

The Potential Hepatoprotective Effect of Vaccinium arctostaphylos L. Fruit Extract in Diabetic Rat.

Vaccinium arctostaphylos has traditionally been employed in Iranian folk medicine to treat diabetes. However, the precise molecular mechanisms underlying its antidiabetic properties remain incompletely understood. The current experiment intended to explore the modulatory effects of V. arctostaphylos fruit ethanolic extract (VAE) on biochemical and molecular events in the livers of diabetic rats. In this experimental study, male Wistar rats were randomly assigned to four groups: normal control, normal rats with VAE treatment, diabetic control, and diabetic rats with VAE treatment. Following 42 days of treatment, the impact of VAE on diabetes-induced rats was assessed by measuring various serum biochemical parameters, including insulin, free fatty acids (FFA), tumor necrosis factor-α (TNF-α), reactive oxygen species (ROS), and adiponectin levels. The activities of hepatic carbohydrate metabolic enzymes and glycogen content were determined. Additionally, expression levels of selected genes implicated in carbohydrate/lipid metabolism and miR-27b expression were evaluated. H and E-stained liver sections were prepared for light microscopy examination. Treatment with VAE elevated levels of insulin and adiponectin that reduced levels of FFA, ROS, and TNF-α in the serum of diabetic rats. VAE-treated rats exhibited increased activities of hepatic glucokinase (GK), glucose-6-phosphate dehydrogenase (G6PD), and glycogen concentrations, in conjunction with decreased activities of glucose-6-phosphatase (G6Pase) and fructose-1,6-bisphosphatase (FBPase). Furthermore, VAE significantly upregulated the transcription levels of hepatic insulin receptor substrate 1 (Irs1) and glucose transporter 2 (Glut2), while considerably downregulated the expression of peroxisome proliferator-activated receptor gamma (Pparg) and sterol regulatory element-binding protein 1c (Srebp1c). VAE remarkably enhanced the expression of miR27-b in the hepatic tissues of diabetic rats. Abnormal histological signs were dramatically normalized in diabetic rats receiving VAE compared to those in the diabetic control group. Our findings underscore the hypoglycemic and hypolipidemic activities of V. arctostaphylos and assist in better comprehension of its antidiabetic properties.

Effect of MTA3 Inhibition of Glutamine Synthetase-Mediated Glutaminolysis on Radiosensitivity of Patients with Esophageal Cancer

Metastasis-associated protein 3 (MTA3) can serve as a tumor suppressor in many cancer types. However, the role of MTA3 in radiosensitivity of patients with esophageal squamous cell cancer (ESCC) remains unclear. We thus investigated the function of MTA3 in radiosensitivity for ESCC, one of the most common digestive cancers. The colony formation assay and nude mice xenograft tumor assay were performed to investigate the effect of MTA3 on radiosensitivity in ESCC. Glutamine consumption assay kit and glutamate production assay kit were used to assess the glutaminolysis. Glutaminase (GLS) Activity Assay Kit and Glutamine Synthetase (GS) Activity Assay Kit were used to analyze the activity of specific metabolic enzymes dominate glutaminolysis. The regulatory mechanism of glutaminolysis by MTA3 was confirmed using Chromatin immunoprecipitation assay and Gaussia luciferase assay. The expression levels of MTA3 and GS in ESCC primary tissues were evaluated using immunohistochemistry. Survival curves were plotted with the Kaplan-Meier method and compared by log-rank test. The colony formation assay showed that MTA3 depletion and overexpression caused significantly higher and lower clonogenic survival after different doses of irradiation (IR), respectively. When these cells were subcutaneously injected into nude mice, the tumors derived from the cells with MTA3 overexpression and MTA3 knockdown were significantly smaller and bigger after IR, respectively. These findings suggest that MTA3 can enhance radiosensitivity in vitro and in vivo. Meanwhile, overexpressed and knockdown MTA3 can repress and expedite glutamine consumption and glutamate production uniformly, respectively. To determine how MTA3 acts on glutaminolysis, the activity of two specific metabolic enzymes dominate this metabolism, GS and GLS, were evaluated. It found that overexpressed and knockdown MTA3 can restrain and enhance the activity of GS, respectively, but have less effect on GLS. Moreover, the decreased radiosensitivity mediated by MTA3 knockdown is significantly increased when treated with GS inhibitor, suggesting that GS plays a crucial role in MTA3-mediated radiosensitivity enhancement. Mechanistically, Chromatin immunoprecipitation assay and Gaussia luciferase assay showed that MTA3 was recruited to the promoter of GS and suppressed GS transcription. However, knockdown of GATA3 abolished MTA3's repressive effect on GS and inhibited the MTA3's occupation on the promoter region of GS. These results collectively demonstrated that, in ESCC cells, MTA3 is recruited by GATA3 to inhibit GS expression, then ultimately represses glutaminolysis and enhances radiosensitivity. Finally, we showed that the ESCC patients in the MTA3low/GShigh group is significantly associated with shorter overall survival. MTA3 is capable of enhancing radiosensitivity through downregulating GS and MTA3low/GShigh might be a potential prognostic factor for ESCC patients.

Mechanical stiffness promotes skin fibrosis through Piezo1-mediated arginine and proline metabolism

The increased mechanics of fibrotic skin tissue continuously regulate fibroblast functions such as survival and differentiation. Although all these processes consume metabolites, it is unclear whether and how cells adapt their metabolic activity to increased matrix stiffness. Here, we show that transferring mouse dermal fibroblasts from soft to stiff substrates causes an up-regulation of arginine and proline metabolism. Increased matrix stiffness stimulates the expression and activity of key metabolic enzymes, leading to the synthesis of L-proline, a major source of collagen. In addition, the novel mechanosensitive channel Piezo1 was identified as a key regulator of arginine and proline metabolism in fibroblasts under increased stiffness. Consistently, targeting Piezo1 to dermal fibroblasts in vivo effectively reduces fibrosis and arginine-proline metabolism in mouse skin. Therefore, mechanical stiffness is a critical environmental cue for fibroblast metabolism and skin fibrosis progression.

Protective effect of bromelain on some metabolic enzyme activities in tyloxapol-induced hyperlipidemic rats.

Elevation of one or more plasma lipids, such as phospholipids, cholesterol esters, cholesterol, and triglycerides, is known as hyperlipidemia. In humans and experimental animals, bromelain, the primary active ingredient isolated from pineapple stems, has several positive effects, including anti-tumor growth, anticoagulation, and anti-inflammation. Hence, the purpose of this study was to determine the possible protective impact of bromelain on some metabolic enzymes (paraoxonase-1, glutathione S-transferase, glutathione reductase, sorbitol dehydrogenase [SDH], aldose reductase [AR], butyrylcholinesterase [BChE], and acetylcholinesterase [AChE]), activity in the heart, kidney, and liver of rats with tyloxapol-induced hyperlipidemia. Rats were divided into three groups: control group, HL-control group (tyloxapol 400mg/kg, i.p. administered group), and HL+bromelain (group receiving bromelain 250mg/kg/o.d. prior to administration of tyloxapol 400mg/kg, i.p.). BChE, SDH, and AR enzyme activities were significantly increased in all tissues in HL-control compared to the control, whereas the activity of other studied enzymes was significantly decreased. Bromelain had a regulatory effect on all tissues and enzyme activities. In conclusion, these results prove that bromelain is a new mediator that decreases hyperlipidemia.

Synthesis, characterization, biochemical, and molecular modeling studies of carvacrol-based new thiosemicarbazide and 1,3,4-thiadiazole derivatives.

A series of carvacrol-based thiosemicarbazide (3a-e) and 1,3,4-thiadiazole-2-amine (4a-e) were designed and synthesized for the first time. The structures were characterized by nuclear magnetic resonanceand high resolution mass spectroscopytechniques. All compounds were examined for some metabolic enzyme activities. Results indicated that all the synthetic molecules exhibited powerful inhibitory actions against human carbonic anhydrase I and II (hCAI and II), acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) enzymes compared to the standard molecules. Ki values of five novel thiosemicarbazides and five new 1,3,4-thiadiazole-2-amine derivatives (3a-e and 4a-e) for hCA I, hCA II, AChE, and BChE enzymes were obtained in the ranges 0.73-21.60, 0.42-15.08 µM, 3.48-81.48, 92.61-211.40 nM, respectively. After the experimental undertaking, an extensive molecular docking analysis was conducted to scrutinize the intricate details of interactions between the ligand and the enzyme in question. The principal focus of this investigation was to appraise the potency and efficacy of the most active compound. In this context, the calculated docking scores were noted to be remarkably low, with values of -8.65, -7.97, -8.92, and -8.32 kcal/mol being recorded for hCA I, hCA II, AChE, and BChE, respectively. These observations suggest a high affinity and specificity of the studied compounds towardthe enzymes, as mentioned earlier, which may pave the way for novel therapeutic interventions aimed at modulating the activity of these enzymes.

Effects of Arbutin on Potassium Bromate-Induced Erythrocyte Toxicity in Rats: Biochemical Evaluation of Some Metabolic Enzyme Activities In Vivo and In Vitro.

In the present study, the inhibitory effect of potassium bromate on the pentose phosphate pathway and intracellular antioxidant systems enzymes (glucose 6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), glutathione reductase (GR), glutathione S-transferase (GST), and thioredoxin reductase (TrxR)) and the role of arbutin in ameliorating this inhibition were investigated. In the in vivo phase of the study, Wistar Albino rats (28 male adults) were randomly divided into four groups. Control (n = 7): isotonic serum (0.5 mL, i.p), potassium bromate group (n = 7): potassium bromate (100 mg/kg), arbutin group (n = 7): arbutin (i.p.) (50 mg/kg/day), potassium bromate + arbutin, and Group (n = 7): potassium bromate (100 mg/kg) + arbutin (50 mg/kg/day) (i.p). The results of in vivo study showed that the activities of G6PD, 6PGD, GR, and TrxR enzymes were strongly inhibited in potassium bromate groups (p < 0.05). It was determined that GST enzyme activity decreased in the potassium bromate group, but this decrease was not statistically significant compared to the control group (p ⩾ 0.05). A statistically significant increase was found in G6PD, 6PGD, GST, and TrxR enzyme activities in the arbutin group compared to the control group (p < 0.05). The increase in GR enzyme activity was not statistically significant (p ⩾ 0.05). The potassium bromate + arbutin group's enzyme activity increased in comparison to the potassium bromate group and was discovered to be closer to the control group. It was found that potassium bromate inhibited the 6PGD enzyme obtained from rat erythrocyte tissues with IC50 = 346 μM value and Ki = 434.4 μM ± 6.1 value, and the inhibition was noncompetitive.

Changes in the content of aminonitrogen and the activity of aminotransferases in saliva in lymphomas

Background. The relevance of studying changes in the activity of metabolic enzymes in saliva in lymphomas lies in the non-invasive method of research, the search for new ways in the diagnosis of oncology to detect the disease in the early stages, as well as to obtain a complete picture of the course of the pathological process. The activity of certain biochemical enzymes is significantly higher in saliva than in blood serum. In addition, saliva is a less hazardous environment for laboratory testing than blood, which reduces the risk of infection for medical personnel. Objective. The aim of this work was to search for biochemical markers in saliva in Hodgkin’s and non-Hodgkin’s lymphomas, the value of which was statistically significantly different from the values of the same markers among healthy subjects included in the control group. Design and methods. In the case-control study, volunteers were divided into 2 groups: the main group, with a histologically confirmed diagnosis of Hodgkin’s lymphoma (53 people) or non-Hodgkin’s lymphoma (82 people) and the control group (135 people), apparently healthy individuals. Inclusion in groups occurred in parallel. All participants underwent a biochemical study of saliva to determine the content of amine nitrogen, the activity of enzymes (AlAT, AsAT, GGT, alkaline phosphatase). The patients of the main group were recruited on the basis of the Clinical Oncological Dispensary (Omsk, Russian Federation). Results. A significant increase in amino nitrogen (p &lt; 0,0084), ALT (p &lt; 0,0205), AST (p &lt; 0,0047), GGT (p&lt;0,0291) was found in the group of patients diagnosed with non-Hodgkin’s lymphoma, compared with subjects from the control group. Conclusion. A preliminary hypothesis was put forward that aminotransferases such as ALT, AST and GGT can be used not only as indicators of liver damage. A change in the activity of amine transferases with a simultaneous increase in the activity of amino nitrogen may reflect a pronounced redistribution of nitrogen in the body for the synthesis of new non-essential amino acids that are necessary for neoplastic cells as structural components for their growth and proliferation. This work also confirms that saliva is an informative diagnostic liquid that can be used in the routine practice of a clinician.

How Do Different Dietary Carbohydrate/Lipid Ratios Influence Intestinal Morphology and Glycolipid Metabolism Capacity in Hybrid Grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂)

Levels of dietary carbohydrates and lipids have important effects on the growth, health, and glycolipid metabolizing capacity of the hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂). This experiment evaluated the effect of carbohydrate to lipid ratios (CHO:L ratio) on growth, serum biochemical indices, intestinal morphology and activity of digestive enzymes, and the ability to metabolize carbohydrates and lipids in the hybrid grouper. Six iso-nitrogenous (500 g/kg) and iso-energetic (190 MJ/kg) feeds with CHO:L ratios of 0.82, 1.03, 1.28, 1.58, 1.94, and 2.27 were formulated. The 720 groupers with an initial body weight of 7.76 ± 0.08 g were sorted into 24 fiberglass buckets of 30 fish each. Feed was delivered twice daily at 8:00 and 16:00 to apparent satiety for 56 days. The results showed that the growth performance of the groupers was not significantly affected by the diet. Based on the specific growth rate (SGR), the optimal CHO:L ratio was 1.72 for the groupers by the second-order polynomial regression model. The intestinal trypsin and lipase, and the hepatic trypsin activities of the groupers showed a maximum in the 1.58 group. The intestinal muscle thickness in the 1.94 group and the villus length in the 1.58 group were significantly greater than in the 0.82, 1.03, 1.28, and 2.27 groups. The glycogen synthase, pyruvate kinase, and hexokinase activities of the liver were significantly higher in the 1.58 group than in the 0.82 and 2.27 groups. The hormone-sensitive triglyceride lipase, adipose triglyceride lipase, acetyl-CoA carboxylase, and carnitine palmitoyl transferase of the liver showed significantly higher activities in the 1.58 group than those in the 0.82 and 1.03 groups. These results showed that based on the SGR of the groupers, the best CHO:L ratio was 1.72. An appropriate dietary CHO:L ratio can reduce the lipid deposition of the fish body, liver, and muscle, as well as improve the intestinal morphology and activities of liver carbohydrate and lipid metabolism enzymes.

Exogenous Salicylic Acid Alleviates NO2 Damage by Maintaining Cell Stability and Physiological Metabolism in Bougainvillea × buttiana 'Miss Manila' Seedlings.

Exogenous substances can alleviate plant damage under adverse conditions. In order to explore whether different concentrations of salicylic acid (SA) can play a role in the resistance of Bougainvillea × buttiana 'Miss Manila' to nitrogen dioxide (NO2) stress and the relevant mechanisms of their effects, different concentrations of SA were applied locally under the control experiment condition of 4.0 μL·L-1 NO2, and the role of SA in alleviating injury was studied. The findings noted a significant increase in metabolic adaptations and antioxidant enzyme activities following 0.25-0.75 mM SA application (p < 0.05), except 1 mM. Superoxide dismutase (SOD) and catalase (CAT) in particular increased by 21.88% and 59.71%, respectively. Such an increase led to effective control of the reduction in photosynthetic pigments and the photosynthetic rate and protection of the structural stability of chloroplasts and other organelles. In addition, the activity of nitrate reductase (NR) increased by 83.85%, and the content of nitrate nitrogen (NO3--N) decreased by 29.23% in nitrogen metabolism. Concurrently, a principal component analysis (PCA) and a membership function analysis further indicated that 0.75 mM SA provided the most notable improvement in NO2 resistance among the different gradients. These findings suggest that 0.25-0.75 mM SA can relieve the stress at 4 μL·L-1 NO2 injury by effectively improving the antioxidant enzyme activity and nitrogen metabolizing enzyme activity, protecting the photosynthetic system and cell structure, but 1 mM SA had the opposite effect. In the future, the specific reasons for inhibition of SA at high concentrations and the comprehensive effects of the application of other exogenous compounds should be further studied.

Invited review: Camel milk–derived bioactive peptides and diabetes—Molecular view and perspectives

In dairy science, camel milk (CM) constitutes a center of interest for scientists due to its known beneficial effect on diabetes as demonstrated in many in vitro, in vivo, and clinical studies and trials. Overall, CM had positive effects on various parameters related to glucose transport and metabolism as well as the structural and functional properties of the pancreatic β-cells and insulin secretion. Thus, CM consumption may help manage diabetes; however, such a recommendation will become rationale and clinically conceivable only if the exact molecular mechanisms and pathways involved at the cellular levels are well understood. Moreover, the application of CM as an alternative antidiabetic tool may first require the identification of the exact bioactive molecules behind such antidiabetic properties. In this review, we describe the advances in our knowledge of the molecular mechanisms reported to be involved in the beneficial effects of CM in managing diabetes using different in vitro and in vivo models. This mainly includes the effects of CM on the different molecular pathways controlling (1) insulin receptor signaling and glucose uptake, (2) the pancreatic β-cell structure and function, and (3) the activity of key metabolic enzymes in glucose metabolism. Moreover, we described the current status of the identification of CM-derived bioactive peptides and their structure-activity relationship study and characterization in the context of molecular markers related to diabetes. Such an overview will not only enrich our scientific knowledge of the plausible mode of action of CM in diabetes but should ultimately rationalize the claim of the potential application of CM against diabetes. This will pave the way toward new directions and ideas for developing a new generation of antidiabetic products taking benefits from the chemical composition of CM.

Twice-split phosphorus application alleviates low-temperature impacts on wheat by improved spikelet development and setting

Extreme low-temperature incidents have become more frequent and severe as climate change intensifies. In Huang-Huai-Hai wheat growing area of China, the late spring coldness occurring at the jointing-booting stage (the anther interval stage) has resulted in significant yield losses of winter wheat. This study attempts to develop an economical, feasible, and efficient cultivation technique for improving the low-temperature (LT) resistance of wheat by exploring the effects of twice-split phosphorus application (TSPA) on wheat antioxidant characteristics and carbon and nitrogen metabolism physiology under LT treatment at the anther interval stage using Yannong 19 as the experimental material. The treatments consisted of traditional phosphorus application and TSPA, followed by a –4°C LT treatment and natural temperature (NT) control at the anther interval stage. Our analyses showed that, compared with the traditional application, the TSPA increased the net photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate (Tr) of leaves and reduced the intercellular carbon dioxide concentration (Ci). The activity of carbon and nitrogen metabolism enzymes in the young wheat spikes was also increased by the TSPA, which promoted the accumulation of soluble sugar (SS), sucrose (SUC), soluble protein (SP), and proline (Pro) in young wheat spike and reduced the toxicity of malondialdehyde (MDA). Due to the improved organic nutrition for reproductive development, the young wheat spikes exhibited enhanced LT resistance, which reduced the sterile spikelet number (SSN) per spike by 11.8% and increased the spikelet setting rate (SSR) and final yield by 6.0 and 8.4%, respectively, compared to the traditional application. The positive effects of split phosphorus application became more pronounced when the LT treatment was prolonged.

Neodymium Nitrate Improves the Germination of Aged Wheat Seeds by Increasing Soluble Substances and Activating Antioxidative and Metabolic Enzymes in Seeds

Seeds stored for a prolonged period are subject to aging and a reduction in germination potential (GP), which will negatively affect seed sales. Rare-earth elements have a synergistic effect on the improvement of seed GP. In this study, we examined the effects of neodymium on biochemical components, the antioxidant protective system, and metabolism-related enzymes during germination of naturally and artificially aged seeds of three wheat cultivars. Seed germination indices, biochemical substance contents, and enzyme activities decreased after seed aging. Soaking seeds in a neodymium nitrate solution revived aged wheat seeds at an optimal concentration of 20 µmol/L for 8 h. Soaking in a neodymium nitrate solution increased the GP4 (by 2.25–60.9%), germination index (by 1.69–29.2%), and vigor index (by 3.36–18.7%) of aged seeds. Compared with non-soaked seeds, soaking significantly changed the contents of biochemical substances, and the activities of antioxidant protective enzymes and metabolic enzymes in seedlings were increased. Soaking with neodymium may revive aged seeds by regulating the synthesis of soluble sugars, soluble proteins, chlorophyll, and carotenoids and decomposing malondialdehyde in the germinating seed. Root dehydrogenase and amylase showed different responses to the aging modes. The differential responses of root dehydrogenase and amylase may reflect differences in the resistance of enzymes to long-term mild seed aging and short-term severe environmental aging.

Effects of exposure to nanoplastics on the gill of mussels Mytilus galloprovincialis: An integrated perspective from multiple biomarkers

The pervasive presence of nanoplastics (NPs) in marine environments poses a threat to marine organisms. Gills, as the organ in direct contact with the environment in marine invertebrates, maybe the first to accumulate NPs. To date, the toxic effects of NPs on the gills of marine invertebrates are still largely unknown. In this study, the response of multiple biomarkers (i.e., total antioxidant capacity, the activity of acetylcholine, ion content and transport enzyme, metabolic enzymes, and lipids content) in mussels Mytilus galloprovincialis exposed to polystyrene nanoplastics (PS-NPs) for 7 days were evaluated. Significant inductions of total antioxidant capacity (T-AOC) and inhibition of acetylcholine (AChE) activity were detected after 7 days of PS-NPs exposure. PS-NPs also triggered significant alteration in ion content (Na+ and K+) and suppressed the activities of the ion transport enzyme (Na+/K+-ATPase). Moreover, we found the activity of metabolic enzymes (succinate dehydrogenase and pyruvate kinase) and lipids content (triacylglycerol and cholesterol) were significantly altered, suggesting the interference of PS-NPs on energy metabolism and lipid metabolism. This investigation provides substantial information to understand the physical responses of invertebrate gills to PS-NPs exposure. Given the crucial ecological roles of invertebrates, the presence of PS-NPs in the marine environment may have far-reaching impacts on population abundance, biodiversity, and stability of the marine ecosystem.

Proline Metabolism Process and Antioxidant Potential of Lycium ruthenicum Murr. in Response to NaCl Treatments.

Salinity influences the level of antioxidants and proline content, which are both involved in the regulation of stress responses in plants. To examine the interplay between the antioxidant system and proline metabolism in plant stress acclimation, explants of Lycium ruthenicum were subjected to NaCl treatments, and the growth characteristics, antioxidant enzyme activities, proline accumulation, and metabolic enzyme content were analyzed. The results revealed that NaCl concentrations between 50 to 150 mM have a positive effect on the growth of L. ruthenicum explants. Increasing NaCl concentrations elevated the activities of superoxide dismutase (SOD) and catalase (CAT), while hydrogen peroxide (H2O2) content was inhibited, suggesting that the elevated antioxidants play a central protective role in superoxide anion (O2•-) and H2O2 scavenging processes in response to NaCl treatments. Also, high proline levels also protect antioxidant enzyme machinery, thus protecting the plants from oxidative damage and enhancing osmotic adjustment. Increasing levels of pyrroline-5-carboxylate synthetase (P5CS), pyrroline-5-carboxylate reductase (P5CR), and ornithine-δ-aminotransferase (δ-OAT) were observed, resulting in elevated level of proline. In addition, the expression levels of LrP5CS1, -2, -3, LrOAT-1, and -2 were promoted in NaCl treatments. According to the combined analysis of metabolic enzyme activities and their relative expression, it is confirmed that the glutamate (Glu) pathway is activated in L. ruthenicum faced with different levels of NaCl concentrations. However, Glu supplied by δ-OAT is fed back into the main pathway for proline metabolism.

Succinylation modification: a potential therapeutic target in stroke.

Stroke is a leading cause of mortality and disability worldwide. Ischemic cell death triggered by the compromised supply of blood oxygen and glucose is one of the major pathophysiology of stroke-induced brain injury. Impaired mitochondrial energy metabolism is observed minutes after stroke and is closely associated with the progression of neuropathology. Recently, a new type of post-translational modification, known as lysine succinylation, has been recognized to play a significant role in mitochondrial energy metabolism after ischemia. However, the role of succinylation modification in cell metabolism after stroke and its regulation are not well understood. We aimed to review the effects of succinylation on energy metabolism, reactive oxygen species generation, and neuroinflammation, as well as Sirtuin 5 mediated desuccinylation after stroke. We also highlight the potential of targeting succinylation/desuccinylation as a promising strategy for the treatment of stroke. The succinylation level is dynamically regulated by the nonenzymatic or enzymatic transfer of a succinyl group to a protein on lysine residues and the removal of succinyl catalyzed by desuccinylases. Mounting evidence has suggested that succinylation can regulate the metabolic pathway through modulating the activity or stability of metabolic enzymes. Sirtuins, especially Sirtuin 5, are characterized for their desuccinylation activity and have been recognized as a critical regulator of metabolism through desuccinylating numerous metabolic enzymes. Imbalance between succinylation and desuccinylation has been implicated in the pathophysiology of stroke. Pharmacological agents that enhance the activity of Sirtuin 5 have been employed to promote desuccinylation and improve mitochondrial metabolism, and neuroprotective effects of these agents have been observed in experimental stroke studies. However, their therapeutic efficacy in stroke patients should be validated.

Effect of calcium spray at flowering combined with post-harvest 1-MCP treatment on the preservation of grapes

These tests were carried out to find out how calcium and 1-MCP treatment affected the preservation of grapes, as grapes are highly susceptible to decay during post-harvest storage. The grapes were treated with 5 g/L calcium at the flowering stage, followed by 1 μL/L 1-MCP treatment after harvesting.When grapevines were treated with a combination of calcium and 1-MCP, the marketable fruit rate (At day 56 of storage, the 1-MCP + Ca2+ treatment group was still 93%, an increase of 29.03% compared to the control group.) and quality improved (At day 28 of storage, the VC content of the 1-MCP + Ca2+ treated group was 4.35 mg/100g, an increase of 25.01% compared to the control group.), while the fruit weight loss rate decreased (At day 56 of storage, the weight loss of the control group was 6.97%, an increase of 39.43% compared to the 1-MCP + Ca2+ treated group.).According to the experimental results, there are several reasons for this. First, in the early stages of fruit storage, the concentration of soluble pectin and soluble fiber, as well as the activities of pectinase and cellulase (related gene levels) were decreased. Secondly, the activity of antioxidant enzymes was increased, while MDA content was decreased. Third, during fruit storage, the respiratory intensity and ethylene release rate were reduced, as was the activity of energy metabolism enzymes. As a result, the aging and deterioration of the fruit during storage were delayed. Principal component analysis revealed that the calcium and 1-MCP combination therapy slowed the decline in grape berry quality, followed by the calcium-treated and 1-MCP-treated fruits. In contrast, grape berry quality declined the most rapidly in the control group.

Carbon Fluxes in Potato (Solanum tuberosum) Remain Stable in Cell Cultures Exposed to Nutritional Phosphate Deficiency.

Nutritional phosphate deficiency is a major limitation to plant growth. Here, we monitored fluxes in pathways supporting respiratory metabolism in potato (Solanum tuberosum) cell cultures growing in control or limiting phosphate conditions. Sugar uptake was quantified using [U-14C]sucrose as precursor. Carbohydrate degradation through glycolysis and respiratory pathways was estimated using the catabolism of [U-14C]sucrose to 14CO2. Anaplerotic carbon flux was assessed by labeling with NaH14CO3. The data showed that these metabolic fluxes displayed distinct patterns over culture time. However, phosphate depletion had relatively little impact on the various fluxes. Sucrose uptake was higher during the first six days of culture, followed by a decline, which was steeper in Pi-sufficient cells. Anaplerotic pathway flux was more important at day three and decreased thereafter. In contrast, the flux between sucrose and CO2 was at a maximum in the mid-log phase of the culture, with a peak at Day 6. Metabolization of [U-14C]sucrose into neutral, basic and acidic fractions was also unaffected by phosphate nutrition. Hence, the well-documented changes in central metabolism enzymes activities in response to Pi deficiency do not drastically modify metabolic fluxes, but rather result in the maintenance of the carbon fluxes that support respiration.

Effect of sowing dates on physiological characteristics, yield, and quality of Carthamus tinctorius

A field experiment was conducted to measure the physiological characteristics, yield, active ingredient content, and other indicators of Carthamus tinctorius leaves undergoing 13 sowing date treatments. The principal component analysis(PCA) and redundancy analysis were used to analyze the correlation between these indicators to explore the effect of sowing date on the yield and active ingredient content of C. tinctorius in Liupanshan of Ningxia. The results illustrated that the early sowing in autumn and spring had significant effects on leaf photosynthetic parameters, SPAD value, antioxidant enzyme activity, nitrogen metabolism enzyme activity, filament yield, grain yield, and hydroxy safflower yellow A(HYSA) of C. tinctorius. Sowing in mid-November and late March had the best effect. Leaf transpiration rate, stomatal conductance, nitrate reductase, nitrite reductase, glutamine synthetase, and glutamate synthase increased by 44.9%, 52.4%, 15.9%, 60.8%, 10.3%, and 38.3%, respectively. The activities of superoxide dismutase, peroxidase, and catalase decreased by 10.8%, 4.1%, and 20.9%, respectively. The improvement of photosynthetic physiological characteristics promoted the dry matter accumulation and reproductive growth of C. tinctorius. The yield of filaments and seeds increased by 15.5% and 11.7%, and the yield of HYSA and kaempferol increased by 17.9% and 20.0%. In short, the suitable sowing date can promote the growth and development of C. tinctorius in Liupanshan of Ningxia, and significantly improve the yield and quality, which is conducive to the high quality and efficient production of C. tinctorius.

Quantification of Glucose Metabolism and Nitrogen Utilization in Two Brassicaceae Species under Bicarbonate and Variable Ammonium Soil Conditions.

In karst habitats under drought conditions, high bicarbonate (high pH), and an abundant nitrate soil environment, bicarbonate regulates the glycolysis (EMP) and pentose phosphate pathways (PPP), which distribute ATP and NADPH, affecting nitrate (NO3-) and ammonium (NH4+) utilization in plants. However, the relationship between EMP PPP and NO3-, and NH4+ utilization and their responses to bicarbonate and variable ammonium still remains elusive. In this study, we used Brassica napus (Bn, a non-karst-adaptable plant) and Orychophragmus violaceus (Ov, a karst-adaptable plant) as plant materials, employed a bidirectional nitrogen-isotope-tracing method, and performed the quantification of the contribution of EMP and PPP. We found that bicarbonate and ammonium inhibited glucose metabolism and nitrogen utilization in Bn under simulated karst habitats. On the other hand, it resulted in a shift from EMP to PPP to promote ammonium utilization in Ov under high ammonium stress in karst habitats. Compared with Bn, bicarbonate promoted glucose metabolism and nitrogen utilization in Ov at low ammonium levels, leading to an increase in photosynthesis, the PPP, carbon and nitrogen metabolizing enzyme activities, nitrate/ammonium utilization, and total inorganic nitrogen assimilation capacity. Moreover, bicarbonate significantly reduced the growth inhibition of Ov by high ammonium, resulting in an improved PPP, RCRUBP, and ammonium utilization to maintain growth. Quantifying the relationships between EMP, PPP, NO3-, and NH4+ utilization can aid the accurate analysis of carbon and nitrogen use efficiency changes in plant species. Therefore, it provides a new prospect to optimize the nitrate/ammonium utilization in plants and further reveals the differential responses of inorganic carbon and nitrogen (C-N) metabolism to bicarbonate and variable ammonium in karst habitats.

Electrochemical Activation of Metabolic Enzymes in Human Liver S9 Fractions

Human liver subcellular fractions such as liver microsomes, liver cytosol fractions, or S9 fractions are widely used in in-vitro assays to predict liver metabolism. The S9 fractions are the supernatants of human liver homogenates consist of both human liver microsomes and the cytosol. Therefore, these fractions contain majority of cytochrome P450 (CYP) enzymes and soluble phase II enzymes like glucuronosyltransferases, N-acetyl transferases, sulfotransferases, and glutathione-S-transferases. Here we report the direct electrochemistry and biocatalytic features of redox active enzymes impregnated in S9 fractions. We investigated the electrochemical properties of S9 films by immobilizing them onto a high purity graphite electrode and performing cyclic voltammetry in anaerobic (Ar saturated) and aerobic (O2 saturated) conditions. The electron transfer between the S9 film and the high purity graphite electrode was observed at the formal potential of -0.48 V, with respect to Ag/AgCl reference electrode, which confirmed the activation of CYP450 reductase enzyme in the film. These films also demonstrated a catalytic oxygen reduction with a maximum current density of ~0.5 mA cm-2 at the scan rate of 0.050V/s. We investigated the CYP activity in the S9 biofilm for phase 1 metabolism using diclofenac hydroxylation as a probe reaction and could able to identify metabolic products using liquid chromatography-mass spectrometry (LC-MS) technique. Eventually, we envision to develop a platform to perform both phase I and II metabolic reactions in a single electrochemical assay.