Activities Of Carbohydrate Metabolizing Enzymes Research Articles

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.

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.
 Keywords: Diabetes Mellitus, High Fat Diet, Metformin, Stingless Bee Pollen

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.

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.

The role of genetic diversity and pre‐breeding traits to improve drought and heat tolerance of bread wheat at the reproductive stage

AbstractExtreme weather including heat waves and drought episodes are expected to increase in intensity and duration due to climate change. Wheat, being a major crop is under extreme threat to these stresses especially at the reproductive stage. This review addresses the potential of diverse wheat germplasm (originated from landraces and synthetic derivatives) to cope with drought and heat stress at the flowering stage. Here, important marker‐trait associations were reported for sustainable grain production under drought and heat stress at anthesis. Likewise, the mechanisms of drought and heat resilience including gene expression and physiological traits (activities of carbohydrate metabolic and antioxidant enzymes, and endogenous hormonal responses) were explored. These studies helped to understand the genetic and physiological basis of drought and heat tolerance and certain pre‐breeding traits related to osmotic adjustment, phytohormonal regulation, antioxidant metabolism, and the expression of novel genes were identified. Moreover, identified pre‐breeding traits and genotypes can be utilized in breeding wheat cultivars resilient to future adverse environments.

A flavonoid-rich fraction of Euphorbia peplus attenuates hyperglycemia, insulin resistance, and oxidative stress in a type 2 diabetes rat model.

Background: Type 2 diabetes (T2D) is a metabolic disorder characterized by insulin resistance (IR) and hyperglycemia. Plants are valuable sources of therapeutic agents for the management of T2D. Euphorbia peplus has been widely used as a traditional medicine for the treatment of various diseases, but its beneficial role in T2D has not been fully explored. Methods: The anti-diabetic efficacy of E. peplus extract (EPE) was studied using rats with T2D induced by high-fat diet (HFD) and streptozotocin (STZ). The diabetic rats received 100, 200, and 400mg/kg EPE for 4 weeks. Results: Phytochemical fractionation of the aerial parts of E. peplus led to the isolation of seven known flavonoids. Rats with T2D exhibited IR, impaired glucose tolerance, decreased liver hexokinase and glycogen, and upregulated glycogen phosphorylase, glucose-6-phosphatase (G-6-Pase), and fructose-1,6-bisphosphatase (F-1,6-BPase). Treatment with 100, 200, and 400mg/kg EPE for 4 weeks ameliorated hyperglycemia, IR, liver glycogen, and the activities of carbohydrate-metabolizing enzymes. EPE attenuated dyslipidemia, serum transaminases, tumor necrosis factor (TNF)-α, interleukin (IL)-1β and liver lipid accumulation, nuclear factor (NF)-κB p65, and lipid peroxidation, nitric oxide and enhanced antioxidants. All EPE doses upregulated serum adiponectin and liver peroxisome proliferator-activated receptor γ (PPARγ) in HFD/STZ-induced rats. The isolated flavonoids showed in silico binding affinity toward hexokinase, NF-κB, and PPARγ. Conclusion: E. peplus is rich in flavonoids, and its extract ameliorated IR, hyperglycemia, dyslipidemia, inflammation and redox imbalance, and upregulated adiponectin and PPARγ in rats with T2D.

Oral administration of Nigella sativa oil attenuates arsenic-induced redox imbalance, DNA damage, metabolic distress, and histopathological alterations in rat intestine

BackgroundExposure to arsenic, a widespread environmental toxin, produces multiple organ toxicity, including gastrointestinal toxicity. Nigella sativa (NS) has long been revered for its numerous health benefits under normal and pathological states. In view of this, the present study attempts to evaluate the protective efficacy of orally administered Nigella sativa oil (NSO) against arsenic-induced cytotoxic and genotoxic alterations in rat intestine and elucidate the underlying mechanism of its action. MethodsRats were categorized into the control, NaAs, NSO, and NaAs+NSO groups. After pre-treatment of rats in the NaAs+NSO and NSO groups daily with NSO (2 ml/kg bwt, orally) for 14 days, NSO treatment was further continued for 30 days, with and without NaAs treatment (5 mg/kg bwt, orally), respectively. Various biochemical parameters, such as enzymatic and non-enzymatic antioxidants, carbohydrate metabolic and brush border membrane marker enzyme activities were evaluated in the mucosal homogenates of all the groups. Intestinal brush border membrane vesicles (BBMV) were isolated, and the activities of membrane marker enzyme viz. ALP, GGTase, LAP, and sucrase were determined. Further, the effect on kinetic parameters viz KM (Michaelis-Menten constant) and Vmax of these enzymes was assessed. Integrity of enterocyte DNA was examined using the comet assay. Histopathology of the intestines was performed to evaluate the histoarchitectural alterations induced by chronic arsenic exposure and/or NSO supplementation. Arsenic accumulation in the intestine was studied by inductively coupled plasma-mass spectroscopy (ICP-MS). ResultsNaAs treatment caused substantial changes in the activities of brush border membrane (BBM), carbohydrate metabolism, and antioxidant defense enzymes in the intestinal mucosal homogenates. The isolated BBM vesicles (BBMV) also showed marked suppression in the marker enzyme activities. Severe DNA damage and mucosal arsenic accumulation were observed in rats treated with NaAs alone. In contrast, oral NSO supplementation significantly alleviated all the adverse alterations induced by NaAs treatment. Histopathological examination supported the biochemical findings. ConclusionNSO, by improving the antioxidant status and energy metabolism, could significantly alter the ability of the intestine to protect against free radical-mediated arsenic toxicity in intestine. Thus, NSO may have an excellent scope in managing gastrointestinal distress in arsenic intoxication.

Arbutin ameliorates hyperglycemia, dyslipidemia and oxidative stress and modulates adipocytokines and PPARγ in high-fat diet/streptozotocin-induced diabetic rats

Arbutin is a glycosylated hydroquinone with antioxidant and anti-hyperglycemia effects. However, its beneficial effects in type 2 diabetes (T2D) were not clarified. This study evaluated the effect of arbutin on hyperglycemia, dyslipidemia, insulin resistance, oxidative stress, and inflammatory response in T2D. Rats induced by high fat diet and streptozotocin were treated with arbutin (25 and 50 mg/kg) for 4 weeks. Diabetic rats exhibited glucose intolerance, elevated HbA1c%, reduced insulin, and high HOMA-IR. Liver glycogen and hexokinase activity were decreased in T2D rats while glucose-6-phosphatase (G6Pase), fructose-1,6- biphosphatase (FBPase), and glycogen phosphorylase were upregulated. Circulating and hepatic cholesterol and triglycerides and serum transaminases were elevated in T2D rats. Arbutin ameliorated hyperglycemia, dyslipidemia, insulin deficiency and resistance, and liver glycogen and alleviated the activity of carbohydrate-metabolizing enzymes. Both doses of arbutin decreased serum transaminases and resistin, and liver lipids, TNF-α, IL-6, malondialdehyde and nitric oxide, downregulated liver resistin and fatty acid synthase, and increased serum and liver adiponectin, and liver reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT). These effects were associated with the upregulation of hepatic PPARγ. Arbutin inhibited α-glucosidase in vitro and in silico investigations revealed the ability of arbutin to bind PPARγ, hexokinase, and α-glucosidase. In conclusion, arbutin effectively ameliorated glucose intolerance, insulin resistance, dyslipidemia, inflammation, and oxidative stress, and modulated carbohydrate-metabolizing enzymes, antioxidants, adipokines and PPARγ in T2D in rats.

Limitation of sucrose biosynthesis shapes carbon partitioning during plant cold acclimation.

Cold acclimation is a multigenic process by which many plant species increase their freezing tolerance. Stabilization of photosynthesis and carbohydrate metabolism plays a crucial role in cold acclimation. To study regulation of primary and secondary metabolism during cold acclimation of Arabidopsis thaliana, metabolic mutants with deficiencies in either starch or flavonoid metabolism were exposed to 4°C. Photosynthesis was determined together with amounts of carbohydrates, anthocyanins, organic acids and enzyme activities of the central carbohydrate metabolism. Starch deficiency was found to significantly delay soluble sugar accumulation during cold acclimation, while starch overaccumulation did not affect accumulation dynamics but resulted in lower total amounts of \sucrose and glucose. Anthocyanin amounts were lowered in both starch deficient and overaccumulating mutants. Vice versa, flavonoid deficiency did not result in a changed starch amount, which suggested a unidirectional signalling link between starch and flavonoid metabolism. Mathematical modelling of carbon metabolism indicated kinetics of sucrose biosynthesis to be limiting for carbon partitioning in leaf tissue during cold exposure. Together with cold-induced dynamics of citrate, fumarate and malate amounts, this provided evidence for a central role of sucrose phosphate synthase activity in carbon partitioning between biosynthetic and dissimilatory pathways which stabilizes photosynthesis and metabolism at low temperature.

Thymoquinone supplementation mitigates arsenic-induced cytotoxic and genotoxic alterations in rat liver

Arsenic, a widespread environmental toxin, produces multiple organ toxicity, including hepatotoxicity. Thymoquinone (TQ) is known to restore liver functions in several hepatic injury models. This study aims to assess the mitigative potential of TQ against sodium arsenate (NaAs)-induced cytotoxic and genotoxic alterations in the liver. Rats were randomly distributed to control, NaAs, TQ, and NaAs+TQ groups. NaAs+TQ and TQ group of rats were pre-treated with TQ (1.5 mg/kg bwt, orally) for 14 days, and the treatment was further continued for 30 days, with and without NaAs treatment (5 mg/kg bwt, orally), respectively. The deleterious histological alterations in the liver of arsenic intoxicated animals were accompanied by an upsurge in the activities of serum ALT and AST, the diagnostic indicators of liver injury. NaAs caused pronounced alterations in the activities of membrane marker and carbohydrate metabolic enzymes and the enzymatic and non-enzymatic components of hepatic antioxidant defense. Significant hepatocyte DNA damage and hepatic arsenic accumulation were also observed in arsenic-exposed rats. TQ supplementation alleviated these adverse alterations and improved the overall hepatic metabolic and antioxidant status in NaAs-administered rats. Prevention of oxidative injury could be the key mechanism of TQ-elicited protective effects. TQ may have an excellent scope as a dietary supplement in the management of arsenic-induced hepatic pathophysiology.

Effects of Digested Pig Slurry on Photosynthesis, Carbohydrate Metabolism and Yield of Tomato (Solanum lycopersicum L.)

Soilless cultivation of vegetables is widely used in production. It is also well accepted that digested slurry is frequently applied as a fertilizer in agricultural production. However, the effect of digested pig slurry on yield and quality of tomato soilless cultivation, as well as the yield and quality influenced by plant carbohydrate metabolism, remain unexplored. Here, the dual inputs of fertilizers (digested pig slurry (D) and mineral fertilizer (M)) and soilless substrates (peat substrate (P) and cinder substrate(C)) consisted of four treatments. The dry biomass and fruit yields, photosynthetic parameters, carbohydrate contents and metabolism enzymes in leaves and fruits were recorded during the experimental period. The highest fruit yields were obtained in DP and MP treatments. Although DP treatment significantly increased the fresh weight of single fruits by 18.0% compared to MP treatment, it reduced the number of ripe fruits. The photosynthetic efficiency and carbohydrate contents (sucrose, glucose and fructose) in leaves were generally higher in DP treatment compared to other treatments, as well as the activities of sucrose phosphate synthase and AGPase in leaves. The soluble sugar contents of fruits in DP and DC treatments were enhanced by 12.3% and 37.0%, respectively, compared to MP and MC treatments. Moreover, the current results showed that DP treatment significantly increased the activity of acid invertase in fruit by 36.3%, 31.3%, and 42.2%, respectively, compared to MP, DC, and MC treatments, and decreased the activity of AGPase by 24.2%, 16.0%, and 36.4%, respectively. The current results have demonstrated that DP treatment had better yield and quality, owing to digested pig slurry increasing the photosynthetic efficiency and source strength, and regulated the activities of carbohydrate metabolism enzymes.

Exogenous Melatonin Reprograms the Rhizosphere Microbial Community to Modulate the Responses of Barley to Drought Stress.

The rhizospheric melatonin application-induced drought tolerance has been illuminated in various plant species, while the roles of the rhizosphere microbial community in this process are still unclear. Here, the diversity and functions of the rhizosphere microbial community and related physiological parameters were tested in barley under the rhizospheric melatonin application and drought. Exogenous melatonin improved plant performance under drought via increasing the activities of non-structural carbohydrate metabolism enzymes and activating the antioxidant enzyme systems in barley roots under drought. The 16S/ITS rRNA gene sequencing revealed that drought and melatonin altered the compositions of the microbiome. Exogenous melatonin increased the relative abundance of the bacterial community in carbohydrate and carboxylate degradation, while decreasing the relative abundance in the pathways of fatty acid and lipid degradation and inorganic nutrient metabolism under drought. These results suggest that the effects of melatonin on rhizosphere microbes and nutrient condition need to be considered in its application for crop drought-resistant cultivation.

Biochanin A Attenuates Hyperglycemia in High-Fat Diet–Streptozotocin–Induced Diabetic Rats by Modulating the Activities of Carbohydrate-Metabolizing Enzymes in Vital Organs

Biochanin A Attenuates Hyperglycemia in High-Fat Diet–Streptozotocin–Induced Diabetic Rats by Modulating the Activities of Carbohydrate-Metabolizing Enzymes in Vital Organs

Regulation of accumulation and metabolism circadian rhythms of starch and sucrose in two leaf-color lettuces by red:blue ratios of LED continuous light

There are interspecies differences in lettuce CL tolerance to LED red and blue light. It is important to clarify the response mechanism of tolerant and sensitive lettuce to CL to achieve efficient application of CL in artificial light plant factories. In the experiment, red-blue LEDs were used to provide a conventional light (360μmol·m−2·s−1, red:blue ratio 4:1 and 18/6 h photoperiod) and three continuous light (CL) treatments with various red:blue ratios (270μmol·m−2·s−1, red:blue ratio 4:1, 2:1 and 1:1) for CL-sensitive and tolerant lettuce cultivars (Yidali and Zishan) with the same daily light integral. The effects of CL quality on the growth, diurnal starch and sucrose accumulation and metabolism of two lettuces were studied by sampling at 6:00, 12:00, 18:00 and 24:00 on the 12 days after light treatment. The results showed that red-blue CL up-regulated shoot biomass of two cultivars, which might be attributed to root and leafy morphology, and chlorophyll content responses. CL with the 80% red light produced the greatest yield, but minor and medium leafy injury was found only on Yidali. CL improved starch and sucrose contents diurnally in two lettuce cultivars, and they totally decreased with blue light proportion. Sucrose synthase (SS), sucrose phosphate synthase (SPS), acid invertase (AI), neutral invertase (NI), adenosine diphosphate glucose pyrophosphorylas (AGP), α-amylase and β-amylase activities under CL were improved in two lettuces compared with the conventional light. Starch and sucrose contents and SS, SPS and AGP activities basically decreased with blue light proportion for two cultivars, while AI, NI, α-amylase and β-amylase activities increased inversely totally. CL irrespectively of its quality disordered the circadian rhythms of carbohydrate accumulation and metabolic enzyme activities in two lettuces. Starch content related closely positively with AGP, α-amylase and β-amylase activities for Zishan, but positively AGP and β-amylase activities for Yidali. Sucrose content correlated negatively with AI and NI activities for Zishan, while positively SS and SPS activities for Yidali. To sum up, red-blue CL with low-dose blue light could improve Yidali and Zishan lettuce yield, starch and sucrose accumulation, and metabolic enzyme activity, but CL disordered the circadian rhythms of carbohydrate accumulation and metabolic enzyme activity irrespectively of spectral quality. Yidali and Zishan lettuces are sensitive and tolerant cultivars to red-blue CL, which is not up to their abilities to maintain circadian rhythms of carbohydrate accumulation and metabolism. Furthermore, starch accumulation in two cultivars was controlled jointly by synthesis and decomposition enzymes, but sucrose accumulation in Yidali lettuce depended on decomposition enzymes rather than synthesis enzyme for purple lettuce.

The cytokinin-producing plant beneficial bacterium Pseudomonas fluorescens G20-18 primes tomato (Solanum lycopersicum) for enhanced drought stress responses

Plant growth-promoting rhizobacteria (PGPR) are known for exerting beneficial effects on plant growth and tolerance to plant pathogens. However, their specific role in mediating protection against abiotic stress remains underexplored. The aim of this study was to characterise the ability of the cytokinin-producing beneficial bacterium Pseudomonas fluorescens G20-18 to enhance tomato growth and boost tolerance to drought stress. Tomato seedlings were root inoculated and their growth and physiological and molecular responses assessed under well-watered conditions and also in response to progressive drought stress and a subsequent recovery period. Root inoculation with G20-18 had a significant positive impact on tomato growth. Furthermore, G20-18 inoculated and drought-stressed plants showed higher leaf chlorophyll and abscisic acid (ABA) content and stomatal closure than non-inoculated controls. Root inoculation also increased the activity of different carbohydrate metabolism enzymes, which are important for root and leaf growth and development in drought stressed plants. A significant increase in the activity of different antioxidant enzymes and total antioxidant capacity correlated with elevated levels of relevant secondary metabolites, such as phenolics, anthocyanins and flavonoids. RNA sequencing revealed distinct qualitative and quantitative differences in gene regulation in response to G20-18. Notably, the number of genes differentially regulated in response to G20-18 was approximately sevenfold higher during drought stress, indicating that root inoculation with the bacteria primed the plants for a much stronger transcriptionally regulated systemic drought stress response. The regulated genes are related to phenylalanine metabolism and other key processes linked to plant growth, development and drought stress resilience. A role of the ability of G20-18 to produce the plant hormone cytokinin for interaction with tomato was established by the cytokinin-deficient biosynthesis mutants CNT1 and CNT2. In comparison with G20-18, the inoculation of plants with CNT1 resulted in a reduced number of differentially regulated genes. The relative change was most prominent under well-watered conditions with a 85 % reduction, corresponding to 462 genes. However, under drought conditions the absolute number of differentially regulated genes was reduced by even 2219 in response to the CNT1 mutant. The relevance of the ability of G20-18 to produce cytokinins for interaction with plants was also evident from differences in growth and specific cell and ecophysiological parameters in response to CNT1 and CNT2. These findings provide novel insights about G20-18's ability to improve drought stress responses and the role of interkingdom signalling by bacterial-derived cytokinins, and contribute to enhance the robustness of the practical application of these microorganisms to improve crop resilience in agricultural production.

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.

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 effect of fullerenols on streptozotocin-induced diabetic rats

We support the general understanding that deleterious effects induced by hyperglycemia in rats would be alleviated by means of antioxidant treatment. Also, we have been supported and encouraged by many explorations on the usage of fullerenols for treating diabetic complications. Our present study aims to examine the potentials of fullerenols against diabetes in streptozotocin-induced diabetic rats. Animals were intraperitoneally administered with fullerenols for 15 days and then sacrificed. Following parameters were assessed: blood glucose, insulin concentration, levels of redox-related parameters, liver and kidney function biomarkers, glycogen contents, carbohydrate metabolic enzyme activities and histopathological analysis. As expected, fullerenols exhibited the well-known anti-oxidative property via decreasing MDA, increasing SOD, GSH-Px and CAT levels. Fullerenol treatment also showed a slight improvement in liver and kidney functional biomarkers, inferring a marginal hepatorenal protection. However, there were insignificant changes in levels of blood glucose, insulin, the pathological state of the necrotic islets. Herein, our results revealed that fullerenols failed to improve the function of pancreas and reverse the hyperglycemia in streptozotocin-induced diabetic rats in spite of a potent antioxidant role. Our study suggested that neither diabetes nor its complications could benefit from fullerenol administration.