Gluconate Research Articles

Glucose determination in human serum by applying inner filter effect quenching mechanism of upconversion nanoparticles.

Accurate blood glucose determination is essential to the clinical diagnosis and management of diabetes. This work establishes an inner filter effect (IFE) strategy between upconversion nanoparticles (UCNPs) and quinone-imine complex for glucose monitoring in human serum simply and efficiently. In this system, the enzyme glucose oxidase (GOx) catalyzes the reaction of glucose into hydrogen peroxide (H2O2) and gluconic acid when compulsion by oxygen. In the presence of horseradish peroxidase (HRP), the produced H2O2 can catalytically oxidize phenol and 4-amino antipyrine (4-AAP) to generate quinone-imine products. The purple-colored quinone-imine complex effectively absorbed the fluorescence of NaYF4:Yb3+, Er3+ UCNPs, leading to the strong fluorescence quenching of UCNPs through IFE. Thus, a new approach was established for glucose monitoring by determining the fluorescence intensity. Under the optimal condition, this approach shows better linearity to glucose from 2-240μmol/L with a low detection limit at 1.0μmol/L. Owing to the excellent fluorescence property and background-free interference of the UCNPs, the biosensor was applied for glucose measurements in human serum and got a satisfactory result. Furthermore, this sensitive and selective biosensor revealed great potential for the quantitative analysis of blood glucose or different kinds of H2O2-involved biomolecules for the application of clinical diagnosis.

Gluconic acid improves performance of newly weaned piglets associated with alterations in gut microbiome and fermentation

BackgroundWeaning is a critical phase in the pigs’ life and gut health might be compromised. Gluconic acid was shown to be poorly absorbed but readily fermented to butyrate in the gut which in turn can improve gut function. Hence, a total of 144 weaning pigs were fed the experimental diets for 42 days. Three treatments were replicated in 8 pens with 6 piglets each: control; low dietary dose of gluconic acid, 9 g/kg; and high dietary dose of gluconic acid, 18 g/kg. After 21 days, one piglet from each pen was sampled for blood haematology and biochemistry, fore- and hindgut digesta characteristics and microbiota, and distal small intestinal histo-morphological indices and gene expression.ResultsFeeding gluconic acid enhanced performance in period d 0–14 post-weaning, in particular feed intake was increased (P = 0.028), though the high dose did not show benefits over the low dose. Regarding d 0–42, feed intake was elevated (P = 0.026). At d 21, piglets fed 18 g/kg gluconic acid showed a trend for lower number of total white blood cells (P = 0.060), caused by particularly lower numbers of lymphocytes as compared to control (P = 0.028). Highly reduced plasma urea was found for groups fed gluconic acid, it amounted to 2.6 and 2.6 mmol/L for the 9 and 18 g/kg level, respectively, as compared to 3.8 mmol/L in control (P = 0.003). Feeding gluconic acid promoted the relative abundance of lactic-acid-producing and acid-utilizing bacteria. In distal small intestine, Lactobacillus amylovorus increased substantially from 11.3 to 82.6% for control and gluconic acid 18 g/kg, respectively (P < 0.05). In mid-colon, the butyrate producers Faecalibacterium prausnitzii (P > 0.05) and Megasphaera elsdenii (P < 0.05) showed highest abundance in gluconic acid 18 g/kg. Consequently, in caecum and mid-colon, increased relative molar percentage of butyrate were found, e.g., 10.0, 12.9 et 14.7% in caecum for gluconic acid at 0, 9, and 18 g/kg, respectively (P = 0.046). Elevated mRNA anti-inflammatory cytokine and survival signalling levels in distal small intestinal mucosa were found by feeding gluconic acid which might be mediated by butyrate.ConclusionsGluconic acid may have potential to alleviate the postweaning growth-check in pigs by altering microbiota composition and fermentation in the gut.

Catalytic Synthesis of Tartaric Acid from Glucose and Gluconic Acid over AuPt/TiO2 Catalysts: Studies on Catalyst Structure–Performance Dependency

Replacing fossil-derived tartaric acid (TA) with sugar-based TA provides a greener route for synthesizing bioplasticizers. However, the detailed mechanism involving C–H and C–C activation of sugar substrates in this area is still under debate. In this work, the plausible reaction mechanism for activation of −CHO (oxidation) and −COOH (decarboxylation) groups in glucose and gluconic acid molecules in the presence of bimetallic AuPt/TiO2 catalysts has been studied and revealed using the UV–vis technique. It is found that Pt and Au phases in bimetallic catalysts selectively promote C–H and C–C cleavage reactions through σ extraction (n−π*) and a π–π (π–π*) coordination mechanism, respectively. The Au2Pt2/TiO2 (Au/Pt: 1/1 atomic ratio) catalyst displays remarkable activity for primary conversion of glucose to gluconic acid (TOF ∼ 20,260 h–1 at 110 °C). Meanwhile, consecutive conversion of gluconic acid to TA can be selectively accelerated by the Au1Pt2/TiO2 (TOF: 3,159 h–1) catalyst. Thus, a record high TA production rate of 12.3 mol/h/molmetal was achieved in this work. Process design and the purification of product mixtures to obtain high quality TA were also proposed and validated at the laboratory scale. The outcome in this work will provide insights for aqueous phase oxidation for synthesis of various valuable sugar-derived carboxylic acids.

Characterization of Delonix regia Flowers’ Pigment and Polysaccharides: Evaluating Their Antibacterial, Anticancer, and Antioxidant Activities and Their Application as a Natural Colorant and Sweetener in Beverages

In the present study, an attempt was made to investigate the in vitro antioxidant, anticancer, and antibacterial activities of Delonix regia, then in vivo evaluate its safety as a natural colorant and sweetener in beverages compared to synthetic colorant and sweetener in rats, then serve the beverages for sensory evaluation. Delonix regia flowers had high protein, polysaccharide, Ca, Na, Mg, K, and Fe contents. The Delonix regia pigment extract (DRPE) polysaccharides were separated and purified by gel permeation chromatography on Sephacryl S-200, characterized by rich polysaccharides (13.6 g/L). The HPLC sugar profile detected the monosaccharides in the extracted polysaccharides, composed of mannose, galactose, glucose, arabinose, and gluconic acid, and the structure of saccharides was confirmed by FTIR, which showed three active groups: carbonyl, hydrocarbon, and hydroxyl. On the other hand, the red pigment constituents of DRPE were detected by HPLC; the main compounds were delphinidin and cyanidin at 15 µg/mL. The DRPE contained a considerable amount (26.33 mg/g) of anthocyanins, phenolic compounds (64.7 mg/g), and flavonoids (10.30 mg/g), thus influencing the antioxidant activity of the DRPE, which scavenged 92% of DPPH free radicals. Additionally, it inhibited the population of pathogenic bacteria, including Staphylococcus aureus, Listeria monocyogenes, Salmonella typhimurum, and Pseudomonas aeruginosa, in the range of 30-90 μg/mL, in addition to inhibiting 85% of pancreatic cancer cell lines. On the in vivo level, the rats that were delivered a diet containing DRPE showed regular liver markers (AST, ALP, and ALT); kidney markers (urea and creatinine); high TP, TA, and GSH; and low MDA, while rats treated with synthetic dye and aspartame showed higher liver and kidney markers; lowered TP, TA, and GSH; and high MDA. After proving the safety of DRPE, it can be safely added to strawberry beverages. Significant sensorial traits, enhanced red color, and taste characterize the strawberry beverages supplemented with DRPE. The lightness and redness of strawberries were enhanced, and the color change ΔE values in DRPE-supplemented beverages ranged from 1.1 to 1.35 compared to 1.69 in controls, indicating the preservative role of DRPE on color. So, including DRPE in food formulation as a natural colorant and sweetener is recommended for preserving health and the environment.

Modeling and tuning of glucose oxidase‐catalase system incorporating dissolved oxygen concentration

AbstractBACKGROUNDGluconic acid production by a glucose oxidase (GOx) and catalase (CAT) system has been proposed. However, the bioprocess optimal design and operation are limited by the lack of kinetic models of GOx involving oxygen as substrate. Herein, the GOx‐CAT system is modeled considering a continuous oxygen supply at a bioreactor lab scale. Initially, experiments and modeling for parameter estimations of and the individual enzymes were conducted. Then, experiments and modeling for the GOx‐CAT system were performed for final model tuning. Additionally, the model quality was evaluated, allowing for a deeper understanding of the system phenomenology.RESULTSFrom the oxygen transport model tuning, a highly accurate estimation was obtained (&gt;0.98 and confidence interval &lt;2%). The highest oxygen transport rate was obtained for the combined system Buffer‐antifoam‐GOx‐CAT that was 2.5 times larger than that obtained for DI water. Kinetic models for the individual enzymes were very accurate and the parameters were fully identifiable. For the integrated system, the gluconic acid evolution was properly predicted and there was a loss of predictive power for the oxygen model. Parameter identifiability analysis showed that and interpretability was compromised. However, the sensitivity analysis indicated that the model must not be simplified.CONCLUSIONHerein its has been demonstrated that is a complex parameter to be estimated for multi‐enzymatic systems due to its dependency on medium composition, particularly with GOx. Nonetheless, based on the acceptable model predictive power, the calculated parameters could be used for studies on the process design phase. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley &amp; Sons Ltd on behalf of Society of Chemical Industry (SCI).

Nanohybrid Double Network Hydrogels Based on a Platinum Nanozyme Composite for Antimicrobial and Diabetic Wound Healing.

Along with hypoxia, severe bacterial infection, and abnormal pH, continuous inflammatory response hinders diabetic wounds from healing. It leads to the accumulation of large amounts of reactive oxygen species (ROS) and therefore prevents the transition of diabetic wounds from the inflammatory phase to the proliferative phase. In this work, a nanohybrid double network hydrogel with injectable, self-healing, and tissue adhesion properties based on a platinum nanozyme composite (PFOB@PLGA@Pt) was constructed to manage diabetic wound healing. PFOB@PLGA@Pt exhibited oxygen supply capacity and enzyme catalytic performance accompanied by pH self-regulation in the entire phases of wound healing. In the first stage, the oxygen carried by perfluorooctyl bromide (PFOB) can ameliorate the hypoxia and boost the glucose oxidase-like catalyzed reaction of Pt NPs, leading to a lowered pH environment with gluconic acid. As a result, the NADH oxidase-like, peroxidase-like, and oxidase-like multiple enzyme activities were activated successively, leading to synergistic antibacterial effects through the production of ROS. After the bacterial infection had cleared, the catalase-like and superoxide dismutase-like activities of Pt NPs reshaped the redox microenvironment by scavenging the excess ROS, which transitioned the wound from the inflammatory phase to the proliferative phase. The microenvironmentally adaptive hydrogel treatment can cover all phases of wound healing, showing the significant promoting effect in the repair of diabetic infected wounds.

Correlations of adaptive potential with metabolic factors in workers of the Yakutia river fleet

Aim. To assess correlations of adaptive potential (AP) with metabolic factors in workers of the Yakutia river fleet before and after the voyage in order to assess the impact of a long voyage.Materials and methods. Before a long voyage in 45 men, a questionnaire was conducted, measurement of height, body weight, heart rate, blood pressure, determination of body mass index and AP. The correlation of AP (according to R.M.Baevsky) with biochemical (aspartate transaminase, alanin transaminase, alkaline phosphatase, gamma glutamyl transferase, lactate dehydrogenase, creatine kinase, glucose, cholesterol, triglycerides) and hormonal (TSH, free T3, free T4, testosterone, cortisol) indicators was evaluated, and also with blood plasma metabolites (62 metabolites) determined by gas chromatography with mass spectrometry before after a long voyage.Results. Distribution by AP level of rivermen – 37.8% have satisfactory adaptive potential, 24.4% have functional stress of adaptive mechanisms, 20.0% have unsatisfactory adaptation and 17.8% have a sharp decrease in the functional capabilities of the circulatory system with the phenomenon of disruption of adaptive mechanisms. The revealed correlations of AP have associations with age, overweight, obesity and metabolic syndrome. Correlations were found with creatinine, testosterone, palmitic acid before the long voyage, and with creatine kinase, glucose, urea, testosterone, gluconic and threonic acids after the voyage. After a long voyage, the number of correlations of AP with metabolic parameters increases.Conclusion. In workers of the Yakutia river fleet the revealed results of metabolic changes indicate an aggravation of disadaptive changes in the conditions of a long voyage. Taking into account the identified features, it is necessary to carry out preventive measures to reduce the severity of disadaptive metabolic changes during a long voyage and rehabilitation actions after the voyage.

Molecular profiling of whey permeate reveals new insights into molecular affinities related to industrial unit operations during lactose production

Lactose powder production from whey permeate generates various side-streams. Molecular profiling of these side-streams and lactose powder can help to detect minor compounds affecting lactose crystallization, lactose powder properties and document the composition of the underutilized side-streams. In this study, whey permeate, lactose powder and intermediate streams from trial lactose productions were analyzed using gas chromatography-mass spectrometry (GC–MS) and proton nuclear magnetic resonance (1H NMR) spectroscopy. In total, 110 compounds were identified and 49 were quantified. Linking the molecular profiles to in-process steps revealed differential compositional attenuation by the unit operations. Small molecules (e.g. methanol) and a few larger molecules (e.g. fatty acids) permeated reverse osmosis membrane, while twenty-three compounds (e.g. hydroxypyruvic acid, malonic acid, gluconic acid and ribonic acid) co-crystallized with lactose and ended up in lactose power. These results help to better understand and control lactose powder production and highlights possibilities to develop new food ingredients.

Development of an intelligent heterojunction fenton catalyst for chemodynamic/starvation synergistic cancer therapy

Chemodynamic therapy (CDT) as an emerging modality in cancer treatment, its implementation remains a daunting challenge by the lack of smart Fenton catalyst under acidic tumor microenvironments. Herein, we have successfully constructed a Fe3O4@MIL-100 heterojunction by growing Fe-based metal-organic framework (MIL-100) onto the surface of Fe3O4 nanoparticles. The as-made heterojunction after encapsulating glucose oxidase (termed FMG) is demonstrated as a pH-responsive intelligent Fenton nanosystem with the synergistic effect of starvation therapy (ST). Density functional theory (DFT) calculations reveal that such heterojunction could greatly reduce the energy barrier of the Fenton reaction, which better explains the mechanism of Fenton performance improvement. Moreover, the encapsulated glucose oxidase has successfully activated the ST process, in which its generated H2O2 and gluconic acid further improve the CDT efficiency. More O2 from the enhanced CDT in turn promotes the enzymatic reaction of glucose oxidase. The Fenton/cascade enzymatic reaction operates in a self-feedback manner as proposed. In vitro and in vivo experiments demonstrate that such intelligent Fenton nanoreactors provide a powerful anticancer mechanism for effective tumor ablation with enough safety. This work provides insights into the developments of MOF-based heterojunctions as powerful anticancer treatment nanoreactors.

A Novel Large-Diameter Optical Fiber Glucose Biosensor Based on Glucose Oxidase– Graphene Oxide–Gold Nanoparticles

A novel glucose large-diameter optical fiber LSPR sensor was constructed based on chemical cross-linking and electrostatic methods of glucose oxidase-graphene oxide-gold nanoparticles (GOD-GO-AuNPs). The GOD-catalyzed oxidation of glucose reacts with oxygen to produce gluconic acid and H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , leading to a change in its ambient refractive index, which in turn leads to a significant shift in the LSPR peak of GO-AuNPs on the fiber. The structure and morphology of GOD-GO-AuNPs were studied by FTIR, UV-vis spectroscopy, SEM, and TEM, respectively. GO improves the stability of the composite particles, reduces the biotoxicity of the metal particles, and the immobilization of glucose oxidase on the surface of the composite particles improved the enzyme activity. A fiber-optic sensor was prepared based on the optimal conditions, and the sensitivity of the sensor was 11.134 nm/(mg/mL) in the range of 0 to 1.0 mL with a response time of 55 s. It showed good anti-interference, selectivity and can be used for real detection. This method combines the advantages of GO, AuNPs, and large diameter fiber-optical which show promise for simple, stable, and cost-effective applications in the field of glucose detection.

Whole-cell biotransformation for simultaneous synthesis of allitol and d-gluconic acid in recombinant Escherichia coli

Allitol and gluconic acid (GA) are important industrial compounds that are preferably produced via bio-production processes. In this research, d-psicose-3-epimerase (DPEase), glucose dehydrogenase (GDH), and ribitol dehydrogenase (RDH) were heterologously expressed in Escherichia coli, realizing the co-production of allitol and GA. Compared to the loss of carbon flux from formate dehydrogenase (FDH), glucose dehydrogenase can produce GA while generating NAD(H). The recombinant strain Ec/pAd-pRrg boosted NADH production to 2.4 μmol/gDCW, 118% higher than with the control strain. Under the optimized conditions, 12.0 g/L allitol and 14.8 g/L GA were produced from 25 g/L d-fructose and 20 g/L d-glucose; i.e., 66.7% and 66.3% higher yields compared to the case of fermentation without optimization, respectively. Furthermore, 42.7 g/L allitol and 56.2 g/L GA can be obtained from pretreated molasses (containing 139.2 g/L d-fructose and 149.1 g/L d-glucose). This work provides a practicable strategy for industrial and efficient co-production of allitol and GA from a cheap raw substrate.

Dual-Functional Nanoplatform Based on Bimetallic Metal-Organic Frameworks for Synergistic Starvation and Chemodynamic Therapy.

Tumor microenvironment (TME)-responsive chemodynamic therapy (CDT) mediated by nanozymes has been extensively studied in oral squamous cell carcinoma. However, the low catalytic efficiency due to insufficient H2O2 in the TME is still a major challenge for its clinical translation. Herein, we present an antitumor nanoplatform based on a Mn-Co organometallic framework material (MnCoMOF), which shows peroxidase-like (POD-like) activity, loaded with glucose oxidase (GOx@MnCoMOF), demonstrating the ability of H2O2 self-supply and H2O2 conversion to toxic hydroxyl radicals. The encapsulated GOx efficiently catalyzes glucose into gluconic acid and H2O2 at the tumor site, which can cut off the energy supply to inhibit tumor growth and produce a large amount of H2O2 and acid to compensate for their lack in the tumor microenvironment. The POD-like activity of MnCoMOF can convert H2O2 into hydroxyl radicals and eliminate tumor cells. The nanoplatform exhibits enhanced tumor cell cytotoxicity in a high-glucose medium compared with a low-glucose medium, illustrating sufficient generation of H2O2 from glucose by GOx. The in vivo results indicate that GOx@MnCoMOF has excellent antitumor efficacy and can remodel the immune-suppressive tumor microenvironment. In conclusion, the GOx@MnCoMOF nanoplatform possesses dual enzymatic activities, i.e., POD-like and glucose oxidase, to achieve improved tumor-suppressive efficiency through synergistic starvation and chemodynamic therapy, thus providing a new strategy for the clinical treatment of oral cancer.

Pomegranate peel extract protects against the development of diabetic cardiomyopathy in rats by inhibiting pyroptosis and downregulating LncRNA-MALAT1.

Background: Pyroptosis is an inflammatory programmed cell death accompanied by activation of inflammasomes and maturation of pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-18. Pyroptosis is closely linked to the development of diabetic cardiomyopathy (DC). Pomegranate peel extract (PPE) exhibits a cardioprotective effect due to its antioxidant and anti-inflammatory properties. This study aimed to investigate the underlying mechanisms of the protective effect of PPE on the myocardium in a rat model of DC and determine the underlying molecular mechanism. Methods: Type 1 diabetes (T1DM) was induced in rats by intraperitoneal injection of streptozotocin. The rats in the treated groups received (150mg/kg) PPE orally and daily for 8weeks. The effects on the survival rate, lipid profile, serum cardiac troponin-1, lipid peroxidation, and tissue fibrosis were assessed. Additionally, the expression of pyroptosis-related genes (NLRP3 and caspase-1) and lncRNA-MALAT1 in the heart tissue was determined. The PPE was analyzed using UPLC-MS/MS and NMR for characterizing the phytochemical content. Results: Prophylactic treatment with PPE significantly ameliorated cardiac hypertrophy in the diabetic rats and increased the survival rate. Moreover, prophylactic treatment with PPE in the diabetic rats significantly improved the lipid profile, decreased serum cardiac troponin-1, and decreased lipid peroxidation in the myocardial tissue. Histopathological examination of the cardiac tissues showed a marked reduction in fibrosis (decrease in collagen volume and number of TGF-β-positive cells) and preservation of normal myocardial structures in the diabetic rats treated with PPE. There was a significant decrease in the expression of pyroptosis-related genes (NLRP3 and caspase-1) and lncRNA-MALAT1 in the heart tissue of the diabetic rats treated with PPE. In addition, the concentration of IL-1β and caspase-1 significantly decreased in the heart tissue of the same group. The protective effect of PPE on diabetic cardiomyopathy could be due to the inhibition of pyroptosis and downregulation of lncRNA-MALAT1. The phytochemical analysis of the PPE indicated that the major compounds were hexahydroxydiphenic acid glucoside, caffeoylquinic acid, gluconic acid, citric acid, gallic acid, and punicalagin. Conclusion: PPE exhibited a cardioprotective potential in diabetic rats due to its unique antioxidant, anti-inflammatory, and antifibrotic properties and its ability to improve the lipid profile. The protective effect of PPE on DC could be due to the inhibition of the NLRP3/caspase-1/IL-1β signaling pathway and downregulation of lncRNA-MALAT1. PPE could be a promising therapy to protect against the development of DC, but further clinical studies are recommended.

Prussian Blue-Derived Nanoplatform for In Situ Amplified Photothermal/Chemodynamic/Starvation Therapy

Chemodynamic therapy (CDT) is an emerging tumor treatment; however, it is hindered by insufficient endogenous hydrogen peroxide (H2O2) and high glutathione (GSH) concentrations in the tumor microenvironment (TME). Furthermore, CDT has limited therapeutic efficacy as a monotherapy. To overcome these limitations, in this study, a nanoplatform is designed and constructed from Cu-doped mesoporous Prussian blue (CMPB)-encapsulated glucose oxidase (GOx) with a coating of hyaluronic acid (HA) modified with a nitric oxide donor (HN). In the proposed GOx@CMPB-HN nanoparticles, the dopant Cu2+ ions are crucial to combining and mutually promoting multiple therapeutic approaches, namely, CDT, photothermal therapy (PTT), and starvation therapy. The dopant Cu2+ ions in CMPB protect against reactive oxygen species to deplete the intracellular GSH in the TME. Additionally, the byproduct Cu+ ions act as a substrate for a Fenton-like reaction that activates CDT. Moreover, H2O2, which is another important substrate, is produced in large quantities through intracellular glucose depletion caused by the nanoparticle-loaded GOx, and the gluconic acid produced in this reaction further enhances the TME acidity and creates a better catalytic environment for CDT. In addition, Cu2+ doping greatly improves the mesoporous Prussian blue (MPB) photothermal conversion performance, and the resultant increase in temperature accelerates CDT catalysis. Finally, the HN coating enables the nanoparticles to actively target CD44 receptors in cancer cells and also enhances vascular permeability. Therefore, this coating has multiple effects, such as facilitating enhanced permeability and retention and deep laser penetration. In vitro and in vivo experiments demonstrate that the proposed GOx@CMPB-HN nanoplatform significantly inhibits tumor growth with the help of in situ enhanced synergistic therapies based on the properties of the TME. The developed nanoplatform has the potential to be applied to cancer treatment and introduces new avenues for tumor treatment research.

Comparative metabolomics of root-tips reveals distinct metabolic pathways conferring drought tolerance in contrasting genotypes of rice

BackgroundThe mechanisms underlying rice root responses to drought during the early developmental stages are yet unknown.ResultsThis study aimed to determine metabolic differences in IR64, a shallow-rooting, drought-susceptible genotype, and Azucena, a drought-tolerant and deep-rooting genotype under drought stress. The morphological evaluation revealed that Azucena might evade water stress by increasing the lateral root system growth, the root surface area, and length to access water. At the same time, IR64 may rely mainly on cell wall thickening to tolerate stress. Furthermore, significant differences were observed in 49 metabolites in IR64 and 80 metabolites in Azucena, for which most metabolites were implicated in secondary metabolism, amino acid metabolism, nucleotide acid metabolism and sugar and sugar alcohol metabolism. Among these metabolites, a significant positive correlation was found between allantoin, galactaric acid, gluconic acid, glucose, and drought tolerance. These metabolites may serve as markers of drought tolerance in genotype screening programs. Based on corresponding biological pathways analysis of the differentially abundant metabolites (DAMs), biosynthesis of alkaloid-derivatives of the shikimate pathway, fatty acid biosynthesis, purine metabolism, TCA cycle and amino acid biosynthesis were the most statistically enriched biological pathway in Azucena in drought response. However, in IR64, the differentially abundant metabolites of starch and sucrose metabolism were the most statistically enriched biological pathways.ConclusionMetabolic marker candidates for drought tolerance were identified in both genotypes. Thus, these markers that were experimentally determined in distinct metabolic pathways can be used for the development or selection of drought-tolerant rice genotypes.

Improved rock phosphate dissolution from organic acids is driven by nitrate assimilation of bacteria isolated from nitrate and CaCO3-rich soil.

Until now, the solubilization capacities of insoluble mineral P by soil microorganisms have been screened in vitro with media containing NH4+ as a nitrogen source. This presence of NH4+ will lead to an acidification of the medium responsible for the solubilization of the insoluble P. However, besides proton release, the production of organic acids can play a very important role in the release of free P. This physiological mechanism can largely depend on the source of nitrogen (NH4+vs NO3-) assimilated by the bacteria but the influence of the N source on the production of organic acids has yet to be studied. Our aim was to investigate if the N source assimilated by bacteria and the soil characteristics such as the dominant N source (NH4+vs NO3-) and CaCO3 contents might influence the bacterial capacities to solubilize rock phosphate. To fill this objective, we screened the capacity of bacteria isolated from 3 soils to solubilize rock phosphate in vitro in presence of NH4+or NO3-. Then, we selected the most efficient bacterial strains to identify and quantify the release of organic anions into the medium. Among the two hundred and forty-three bacterial strains isolated from the 3 soils, nine and seven isolates were identified with the highest % rock phosphate-solubilization values with NH4+ or NO3- as the sole N-source. Only one strain was able to release free Pi with NH4+ or NO3- as the sole N-source. The most predominant organic acids released by almost all isolates were gluconic acid, lactic acid, glycolic acid, acetic acid, formic acid and pyruvic acid regardless the N-source. However, with NO3- as source of N, the highest concentrations on those acids were found together with the highest release of free Pi into the medium. Molecular analysis of 16S rRNA indicated that almost all strains belonged to Bacillus and Paenibacillus genera. The PCA analysis between soil properties and bacterial capacities to release organic acids and free Pi also revealed that soil factors such as CaCO3 and soil NO3- content positively influenced the release of organic acids by bacteria grown in vitro. Our results concluded that the bacterial rock phosphate-solubilization was intimately related to organic acids production which in turn seemed to be driven by the assimilation of NO3- by bacteria. Therefore, the N-source might be considered a key factor to take into consideration during the screening and selection of suitable strains involved in the P-solubilization.

A multifunctional nanocatalyst based on ultra-fluorescent carbon quantum dots for cascade enzymatic activity and stimuli-responsive chemotherapy of cancer

Clinical studies have switched from monotherapy to multimodal therapy due to the intricacy, multiplicity, and unpredictability of malignant tumors. In this work, we report one-pot microwave synthesis of highly fluorescent copper, nitrogen, and sulfur-doped carbon quantum dots (Cu,N,S-CQDs) with superior quantum yield (84%) and enhanced peroxidase-like activity. Then, Cu,N,S-CQDs was further biofunctionalized with glucose oxidase (GOx) and camptothecin (CPT) to form a multifunctional Cu,N,S-CQDs@GOx/CPT (CuCGC) nanocatalysts. The release of Cu2+ and S2− ions from CuCGC were promoted under acidic condition and catalyze the productions of hydroxyl (•OH) radical and H2S gas for chemodynamic (CDT) and gas (GT) therapy of cancer. Besides the CDT and GT effects, CuCGC also stimulates the breakdown of glucose into gluconic acid and peroxide solution for starvation therapy (ST) and ST-guided self-supplied CDT. CuCGC produce large quantities of reactive oxygen species (ROS) in the presence of H2O2 and glucose for enhanced cancer therapy via CDT and ST-guided CDT mechanisms. Interestingly, CuCGC nanocatalysts demonstrates ROS-responsive CPT release upon activation with H2O2 and glucose by CDT and ST-guided CDT, with about 66% of drug release was achieved in this study. In vitro analysis confirmed that our material reveals better biocompatibility towards cancer cells and caused substantial cell damage upon activation with H2O2and glucose through GT, CDT, ST, and chemotherapeutic mechanisms. Therefore, the designing of CuCGC nanocatalysts by coupling ROS-generator with stimuli-responsive drug was potential candidates in clinical studies.

Base-free selective oxidation of monosaccharide into sugar acid by surface-functionalized carbon nanotube composites

Selective oxidation of biomass-derived monosaccharide into high value-added chemicals is highly desirable from sustainability perspectives. Herein, we demonstrate a surface-functionalized carbon nanotube-supported gold (Au/CNT-O and Au/CNT-N) catalyst for base-free oxidation of monosaccharide into sugar acid. Au/CNT-O and Au/CNT-N surfaces successfully introduced oxygen- and nitrogen-containing functional groups, respectively. The highest yields of gluconic acid and xylonic acid were 93.3% and 94.3%, respectively, using Au/CNT-N at 90 °C for 240 min, which is higher than that of using Au/CNT-O. The rate constants for monosaccharide decomposition and sugar acid formation in Au/CNT-N system were higher, while the corresponding activation energy was lower than in Au/CNT-O system. DFT calculation revealed that the mechanism of glucose oxidation to gluconic acid involves the adsorption and activation of O2, adsorption of glucose, dissociation of the formyl C-H bond and formation of O-H bond, and formation and desorption of gluconic acid. The activation energy barrier for the glucose oxidation over Au/CNT-N is lower than that of Au/CNT-O. The nitrogen-containing functional groups are more beneficial for accelerating monosaccharide oxidation and enhancing sugar acid selectivity than oxygen-containing functional groups. This work presents a useful guidance for designing and developing highly active catalysts for producing high-value-added chemicals from biomass.

Accelerated Cream Cheese Technology Development with Combined Acidification

Сream cheese is a variety of fermented milk cheeses. In its production a man formed the cheese mass by the acid-rennet coagulation. Traditional technology implies a long process of obtaining a clot and its separation from the serum, which is due to the slow increase in the milk mixture acidity. The research aim is to reveal the milk mixture fat impact on the fermentation process dynamics and the quality indicators of cream cheese with combined (sourdough and gluconic acid) acidification. The thesis concerns the technology of soft cream cheese obtained by the combined acidification along with acid-rennet clotting. While the mix fermentation richness increasing, the decrease rate in active acidity grows. The active acidity is lower in samples with an increased mass fraction of fat in both cheese and whey compared to lower fat samples. The active acidity of cream cheese ranges from 4.25 to 4.40 pH units. The use of cream cheeses of a normalized fat mass fraction up to 6–8 % of the milk mixture in the technology, the gluconic acid solution introduction into the mixture first to obtain 6.0 pH units of the milk mixture with subsequent introduction of a starter culture of mesophilic Lactococcus enables to accelerate the acid-rennet clot process in a cheese bath. Cream cheese has a soft smearing consistency, a pronounced sour-creamy taste. It has high organoleptic and physico-chemical characteristics defined by constancy from one production process to another in accordance with the selected technological parameters. A man recommends cream cheese for the HoReCa sector, as well as households.

High efficiency chemical mechanical polishing for silicon wafers using a developed slurry

Improving the material removal rate (MRR) of silicon wafers is a challenge in chemical mechanical polishing (CMP), to meet the demands of the development of integrated circuits. In this study, four environmentally friendly additives, including sorbitol, gluconic acid, citric acid, and ammonium citrate, were incorporated into polishing slurries to promote the MRR of silicon wafers. The polishing results reveal that the highest MRR was obtained by ammonium citrate as an additive. When the concentration of ammonium citrate was 0.05 mol/L, the MRR increased by 71.6% to 1979.88 Å/min, and the surface roughness Sa was decreased from 1.131 nm to 0.563 nm. Meanwhile, the polishing slurry containing colloidal silica as abrasives maintained good dispersibility. Polishing mechanism was interpreted using electrochemical analysis, X-ray photoelectron spectroscopy, and coefficient of friction tests. It is indicated that NH4+ions, generated by hydrolysis of ammonium citrate, could modify the electrical characteristics of the silicate layer and catalyze the chemical reactions between Si atoms and H2O on the surface of silicon wafers. This work emphasizes the interfacial action between the polishing slurry and silicon wafers and provides a new idea for high efficiency CMP of silicon wafers in the manufacture of integrated circuits and photovoltaic industry.