Selective synergistic effects of oxalic acid and salicylic acid in enhancing amino acid levels and alleviating lead stress in Zea mays L.

Lead is one of the major environmental pollutants which is highly toxic to plants and living beings. The current investigation thoroughly evaluated the synergistic effects of oxalic acid (OA) and salicylic acid (SA) on Zea mays L. plants subjected to varying durations (15, 30, 30, and 45 days) of lead (Pb) stress. Besides, the effects of oxalic acid (OA) combined with salicylic acid (SA) for different amino acids at various periods of Pb stress were also investigated on Zea mays L. The soil was treated with lead nitrate Pb (NO3)2 (0.5 mM) to induce Pb stress while the stressed plants were further treated using oxalic acid (25 mg/L), salicylic acid (25 mg/L), and their combination OA + SA (25 mg/L each). Measurements of protein content, malondialdehyde (MDA) levels, guaiacol peroxidase (GPOX) activity, catalase (CAT) activity, GSH content, and Pb concentration in maize leaves were done during this study. MDA levels increased by 71% under Pb stress, while protein content decreased by 56%, GSH content by 35%, and CAT activity by 46%. After treatment with SA, OA, and OA+SA, there was a significant reversal of these damages, with the OA+SA combination showing the highest improvement. Specifically, OA+SA treatment led to a 45% increase in protein content and a 39% reduction in MDA levels compared to Pb treatment alone. Moreover, amino acid concentrations increased by 68% under the Pb+OA+SA treatment, reflecting the most significant recovery (p < 0.0001).

THE IMPACT OF DIAMIDE DERIVATIVES OF OXALIC ACID ON FREE RADICAL LIPID OXIDATION IN WHITE RAT BRAIN AND LIVER.

Antioxidants are widely used in medicine due to their ability to bind free radicals - active biomolecules that destroy the genetic apparatus of cells and the structure of their membranes, which makes it possible to reduce the intensity of oxidative processes in the body. In a living organism, free radicals are involved in various processes, but their activity is controlled by antioxidants. The purpose of this work was to conduct a series of studies to identify the antioxidant activity of new synthesized compounds of a series of oxalic acid diamides in the brain and liver tissue of white rats in vivo and in vitro experiments, as well as to determine their potential pharmacological properties. The studies were conducted on outbred white male rats, weighing 180-200 g, kept on a normal diet. After autopsy, the brain and liver were isolated, washed with saline, cleared of blood vessels, and homogenized in Tris-HCl buffer (pH-7.4) (in vitro). The research results showed significant antioxidant activity (AOA) of all compounds with varying effectiveness. The most pronounced activity was demonstrated by compound SV-425 in both brain and liver tissues. Compound SV-427 demonstrated the least activity, with levels in brain tissue and liver tissue. In addition, all physicochemical descriptors of the studied compounds comply with Lipinski's rule of five to identify new molecules for the treatment of oxidative stress. From the data obtained, it can be concluded that the studied compounds have antioxidant properties, helping to protect cells from oxidative stress. This is important for the prevention and treatment of diseases associated with increased levels of free radicals.

An antimicrobial film of silver/nanocellulose crystal/oxalic acid/polyvinyl alcohol with real-time bactericidal and prevention of biofilm formation properties.

Silver nanoparticles (AgNPs) is an excellent antibacterial agent, which is widely used in medical, food, environmental and other fields, but AgNPs are easy to accumulate in aqueous solution, so their application in various fields is limited. Therefore, it is particularly important to propose a new application method or to prepare a new composite material. In this study, OA/PVA was obtained by cross-linking oxalic acid (OA) with polyvinyl alcohol (PVA). Then Ag/NCC was obtained by in situ reduction of AgNPs on nanocellulose crystals (NCC). Finally, Ag/NCC/OA/PVA composite antimicrobial films with good waterproofing effect were prepared by mixing Ag/NCC with OA/PVA. Subsequently, the films were characterized using SEM, UV-vis, FTIR and XRD, as well as physicochemical properties such as mechanical strength and hydrophilic properties were determined. The results indicated that the Ag/NCC/OA/PVA films possess good light transmittance, mechanical properties, water resistance, antibacterial activity, and biodegradability. The results of the mechanism study showed that Ag/NCC/OA/PVA films can destroy cell integrity, inhibit succinate dehydrogenase (SDH) activity, thereby reducing intracellular ATP levels. And induce a large number of reactive oxygen species (ROS) production, eventually leading to the death of C. sakazakii. In summary, Ag/NCC/OA/PVA film has good physical and chemical properties, antibacterial activity and biocompatibility, and has promising applications in food and medical antibacterial fields.

No evidence to support the use of glycerol-oxalic acid mixtures delivered via paper towel for controlling Varroa destructor (Mesostigmata: Varroidae) mites in the Southeast United States.

A significant amount of researcher and practitioner effort has focused on developing new chemical controls for the parasitic Varroa destructor mite in beekeeping. One outcome of that has been the development and testing of "glycerol-oxalic acid" mixtures to place in colonies for extended periods of time, an off-label use of the otherwise legal miticide oxalic acid. The majority of circulated work on this approach was led by practitioners and published in nonacademic journals, highlighting a lack of effective partnership between practitioners and scientists and a possible failure of the extension mandate in beekeeping in the United States. Here, we summarize the practitioner-led studies we could locate and partner with a commercial beekeeper in the Southeast of the United States to test the "shop towel-oxalic acid-glycerol" delivery system developed by those practitioners. Our study, using 129 commercial colonies between honey flows in 2017 split into 4 treatment groups, showed no effectiveness in reducing Varroa parasitism in colonies exposed to oxalic acid-glycerol shop towels. We highlight the discrepancy between our results and those circulated by practitioners, at least for the Southeast, and the failure of extension to support practitioners engaged in research.

Inducing a summer brood break increases the efficacy of oxalic acid vaporization for Varroa destructor (Mesostigmata: Varroidae) control in Apis mellifera (Hymenoptera: Apidae) colonies.

The ectoparasitic mite, Varroa destructor (Anderson and Trueman), is the leading cause of western honey bee colony, Apis mellifera (L.), mortality in the United States. Due to mounting evidence of resistance to certain approved miticides, beekeepers are struggling to keep their colonies alive. To date, there are varied but limited approved options for V. destructor control. Vaporized oxalic acid (OA) has proven to be an effective treatment against the dispersal phase of V. destructor but has its limitations since the vapor cannot penetrate the protective wax cap of honey bee pupal cells where V. destructor reproduces. In the Southeastern United States, honey bee colonies often maintain brood throughout the year, limiting the usefulness of OA. Prior studies have shown that even repeated applications of OA while brood is present are ineffective at decreasing mite populations. In the summer of 2021, we studied whether incorporating a forced brood break while vaporizing with OA would be an effective treatment against V. destructor. Ninety experimental colonies were divided into 2 blocks, one with a brood break and the other with no brood break. Within the blocks, each colony was randomly assigned 1 of 3 treatments: no OA, 2 g OA, or 3 g OA. The combination of vaporizing with OA and a forced brood break increased mite mortality by 5× and reduced mite populations significantly. These results give beekeepers in mild climates an additional integrated pest management method for controlling V. destructor during the summer season.

The effects of thymol, oxalic acid (Api-Bioxal) and hops extract (Nose-Go) on viability, the Nosema sp. spore load and the expression of vg and sod-1 genes in infected honey bees.

This study was done to investigate the effects of thymol, fumagillin, oxalic acid (Api-Bioxal) and hops extract (Nose-Go) on Nosema sp. spore load, the expression of vitellogenin (vg) and superoxide-dismutase-1 (sod-1) genes and mortality of bees infected with N. ceranae. Five healthy colonies were assigned as the negative control, and 25 Nosema sp. infected colonies were assigned to five treatment groups including: the positive control: no additive to sirup; fumagillin 26.4 mg/L, thymol 0.1 g/L, Api-Bioxal 0.64 g/L and Nose-Go 5.0 g/L sirup. The reduction in the number of Nosema sp. spores in fumagillin, thymol, Api-Bioxal and Nose-Go compared to the positive control was 54, 25, 30 and 58%, respectively. Nosema sp. infection in all infected groups increased (p < .05) Escherichia coli population compared to the negative control. Nose-Go had a negative effect on lactobacillus population compared to other substances. Nosema sp. infection decreased vg and sod-1 genes expression in all infected groups compared to the negative control. Fumagillin and Nose-Go increased the expression of vg gene, and Nose-Go and thymol increased the expression of sod-1 gene than the positive control. Nose-Go has the potential to treat nosemosis if the necessary lactobacillus population is provided in the gut.

Postharvest sclerotinia rot control in carrot by the natural product hinokitiol and the potential mechanisms involved.

Sclerotinia rot infected by cosmopolitan fungi Sclerotinia sclerotiorum is a serious and destructive disease in carrot production, especially during their postharvest storage. Natural products with the advantages of environmentally friendly and safety have been widely concerned. This research estimated the impact of hinokitiol against S. sclerotiorum and on the quality of carrots. In vitro and in vivo tests demonstrated that hinokitiol had promising antifungal activities against both carbendazim-susceptible and -resistant isolates of S. sclerotiorum. Importantly, it effectively kept the quality and prolonged the shelf life of carrot by declining the loss of weight, ascorbic acid, carotenoid, and total phenolics content, preventing the formation of malondialdehyde, and enhancing the activities of antioxidant enzymes. Further study found that hinokitiol inhibited the formation of sclerotia by destroying the morphology and the integrality of cell membrane, reduced the pathogenicity by suppressing the synthesis of oxalic acid and exopolysaccharide, declined the activities of enzymes and the gene expression related to sclerotia development in S. sclerotiorum. These information evidenced the great potential of hinokitiol as a natural fresh-keeping agent for the management of postharvest decay infected by S. sclerotiorum.

Assessing Repeated Oxalic Acid Vaporization in Honey Bee (Hymenoptera: Apidae) Colonies for Control of the Ectoparasitic Mite Varroa destructor.

The American beekeeping industry continually experiences colony mortality with annual losses as high as 43%. A leading cause of this is the exotic, ectoparasitic mite, Varroa destructor Anderson & Trueman (Mesostigmata: Varroidae). Integrated Pest Management (IPM) options are used to keep mite populations from reaching lethal levels, however, due to resistance and/or the lack of suitable treatment options, novel controls for reducing mites are warranted. Oxalic acid for controlling V. destructor has become a popular treatment regimen among commercial and backyard beekeepers. Applying vaporized oxalic acid inside a honey bee hive is a legal application method in the U.S., and results in the death of exposed mites. However, if mites are in the reproductive stage and therefore under the protective wax capping, oxalic acid is ineffective. One popular method of applying oxalic is vaporizing multiple times over several weeks to try and circumvent the problem of mites hiding in brood cells. By comparing against control colonies, we tested oxalic acid vaporization in colonies treated with seven applications separated by 5 d (35 d total). We tested in apiaries in Georgia and Alabama during 2019 and 2020, totaling 99 colonies. We found that adult honey bees Linnaeus (Hymenoptera: Apidae), and developing brood experienced no adverse impacts from the oxalic vaporization regime. However, we did not find evidence that frequent periodic application of oxalic during brood-rearing periods is capable of bringing V. destructor populations below treatment thresholds.

Salicylic acid and oxalic acid in enhancing the quality and extending the shelf life of grape cv. Thompson seedless.

Postharvest life of table grapes is usually shortened by berry softening, berry drop, stem browning, fungal decay. Salicylic acid reduces fruit respiration and ethylene biosynthesis, during storage of fruits. Similarly, application of oxalic acid is a secure and hopeful postharvest handling technology for keeping quality and prolonging storage life of fruit. To study the effect of Salicylic acid and oxalic acid in enhancing the quality and extending the shelf life of grape, the present investigation was conducted. The grape berries were treated with Oxalic acid (OA) (1, 2, 3, 4, and 5 mM) and Salicylic acid (SA) (0.5, 1, 1.5 and 2 mM). The treatments were compared within 16th days at an interval of 4 days. Among the treatments, SA (2 mM) showed superiority in different quality attributing characters like physiological loss in weight (PLW), berry firmness, rachis browning, berry appearance, fungal decay, berry shattering, TSS, ascorbic acid, titratable acidity, total sugars, reducing sugars, TSS: acid ratio, taste, overall acceptability and shelf life. Hence, SA (2 mM) can be used as an effective strategy for maintaining quality of table grapes.

Novel Disk Diffusion Assay on Magnesium Oxalate Agar To Evaluate the Susceptibility of Yersinia pestis to Type III Secretion System Inhibitors.

Current methods for screening small molecules that inhibit the plasmid pCD1-encoded Yersinia pestis type III secretion system (T3SS) include lengthy growth curves followed by multistep luminescence assays or Western blot assays to detect secretion, or lack thereof, of effector proteins. The goal of this research was to develop a novel disk diffusion assay on magnesium oxalate (MOX) agar as a simple way to evaluate the susceptibility of Y. pestis to type III secretion system inhibitors. MOX agar produces distinct Y. pestis growth characteristics based on the bacteria's ability or inability to secrete effector proteins; small, barely visible colonies are observed when secretion is activated versus larger, readily visible colonies when secretion is inhibited. Wild-type Y. pestis was diluted and spread onto a MOX agar plate. Disks containing 20 µl of various concentrations of imidocarb dipropionate, a known Y. pestis T3SS inhibitor, or distilled water (dH2O) were placed on the plate. After incubation at 37°C for 48 h, visible colonies of Y. pestis were observed surrounding the disks with imidocarb dipropionate, suggesting that T3S was inhibited. The diameter of the growth of colonies surrounding the disks increased as the concentration of the T3SS inhibitor increased. Imidocarb dipropionate was also able to inhibit Y. pestis strains lacking effector Yops and Yop chaperones, suggesting that they are not necessary for T3S inhibition. This disk diffusion assay is a feasible and useful method for testing the susceptibility of Y. pestis to type III secretion system inhibitors and has the potential to be used in a clinical setting. IMPORTANCE Disk diffusion assays have traditionally been used as a simple and effective way to screen compounds for antibacterial activity and to determine the susceptibility of pathogens to antibiotics; however, they are limited to detecting growth inhibition only. Consequently, antimicrobial agents that inhibit virulence factors, but not growth, would not be detected. Therefore, we developed a disk diffusion assay that could detect inhibition of bacterial virulence factors, specifically, type III secretion systems (T3SSs), needle-like structures used by several pathogenic bacteria to inject host cells with effector proteins and cause disease. We demonstrate that magnesium oxalate (MOX) agar can be used in a disk diffusion assay to detect inhibition of the T3SS of Yersinia pestis, the causative agent of bubonic plague, by small-molecule inhibitors. This assay may be useful for screening additional small molecules that target bacterial T3SSs or testing the susceptibility of patient-derived samples to drugs that target T3SSs.

HTS-based discovery and optimization of novel positive allosteric modulators of the α7 nicotinic acetylcholine receptor.

HTS campaign of the corporate compound collection resulted in a novel, oxalic acid diamide scaffold of α7 nACh receptor positive allosteric modulators. During the hit expansion, several derivatives, such as 4, 11, 17 demonstrated not only high in vitro potency, but also in vivo efficacy in the mouse place recognition test. The advanced hit molecule 11 was further optimized by the elimination of the putatively mutagenic aromatic-amine building block that resulted in a novel, aminomethylindole compound family. The most balanced physico-chemical and pharmacological profile was found in case of compound 55. Docking study revealed an intersubunit binding site to be the most probable for our compounds. 55 demonstrated favorable cognitive enhancing profile not only in scopolamine-induced amnesia (place recognition test in mice) but also in natural forgetting (novel object recognition test in rats). Compound 55 was, furthermore, active in a cognitive paradigm of high translational value, namely in the rat touch screen visual discrimination test. Therefore, 55 was selected as a lead compound for further optimization. Based on the obtained favorable results, the invented aminomethylindole cluster may provide a viable approach for cognitive enhancement through positive allosteric modulation of α7 nAChRs.

Time-course of the effect of potassium oxalate in the treatment of hypersensitive dentine in man.

OBJECTIVE: Investigate the cause of hypersensitive dentine (HD) by recording the time course of changes in dentine sensitivity, sensory threshold to electrical stimulation (ET) and pulpal blood flow (PBF) following tubular occlusion using in vitro and clinical experiments. DESIGN: Nineteen teeth with HD and 13 with normal dentine from 8 participants were evaluated, and the intensity of any pain produced by various stimuli was recorded at different times after oxalate treatment. The participants used a visual-analogue scale (VAS) to indicate the intensity of any pain. The ET and PBF were recorded at the same times. RESULTS: Preliminary in vitro experiments showed that oxalate treatment had no effect on the method used to record PBF, and blocked the treated tubules immediately after application. Considering teeth with HD, a decrease in the median VAS evoked by all forms of stimulation was observed at all post-treatment times, except immediately after treatment (p < 0.05), while the treatment produced no significant effect in teeth with normal dentine. No significant changes in ET or PBF was observed in any of the groups. CONCLUSIONS: The effect of oxalate in relieving the symptoms of HD is not only due to a reduction in the intensity of stimulation of sensory receptors sensitive to fluid flow in the dentinal tubules, but also to a reduce in the sensitivity of the receptors that respond to dentine stimulation. There was no evidence that acute pulpitis or central sensitization to pain, which would be associated with changes in PBF or ET, contributes to HD.

Exploring interaction dynamics of designed organic cocrystal charge transfer complex of 2-hydroxypyridine and oxalic acid with human serum albumin: Single crystal, spectrophotometric, theoretical and antimicrobial studies.

As human serum albumin (HSA) being the most abundant blood protein involved in the role of transport of molecules (drugs), we have designed HSA binding organic charge transfer complex between 2-hydroxypyridine (donor) and oxalic acid (acceptor) showing antimicrobial activities. The type of interactions between HSA and synthesized complex at the molecular level was studied through fluorescence spectroscopy. Binding constant along with the type of quenching mechanism was shown through the Stern Volmer equation. Molecular docking tool also justifies the binding results obtained from fluorescence by providing different interactions, FEB, hydrogen bonding and H-bonding surfaces. Antimicrobial activity was screened against three bacteria - Escheichia coli, Bacteria subtilis and Staphylococus aureus strain and three fungi - Aspergillus Niger, Candida Albicans and Fusarium Oxysporun using disc diffusion method. The characterization of the complex was done through different techniques (FTIR, UV-vis spectroscopy, TGA-DTA). Job's method along with single crystal XRD provides 2:1 stoichiometry and O⋯H-O type of H-bonding between acceptor and donor molecule. Physical parameters (KCT, εCT, ID, ΔG°, µEN, f and RN) were also calculated for the synthesized complex. Theoretical computational data (DFT and Hirshfeld surface) have also been calculated for the complex.

Effect of postharvest oxalic acid application on enzymatic browning and quality of lotus (Nelumbo nuciferaGaertn.) root slices.

Post-cut surface browning is one of the major constraints for shelf-life extension of lotus root slices. In the present study, lotus roots slices were treated with 0, 5 and 10 mmol L-1 oxalic acid and stored at 20 ± 1 °C for 5 days. Results showed that 10 mmol L-1 oxalic acid treated lotus slices exhibited reduced browning, superoxide anion, hydrogen peroxide, electrolyte leakage and malondialdehyde content than control. The 10 mmol L-1 treated slices had better visual quality and higher ascorbic acid and total phenolic contents. In addition, 10 mmol L-1 treated slices showed reduced total bacterial count along with lower soluble quinones, peroxidase and polyphenol oxidase activities in contrast to control. Similarly, 10 mmol L-1 treatment showed higher superoxide dismutase, catalase and ascorbate peroxidase activities as compared to control. In conclusion, 10 mmol L-1 oxalic acid application could be considered suitable to delay post-cut browning of lotus root slices.

Elucidation of the mechanisms into effects of organic acids on soil fertility, cadmium speciation and ecotoxicity in contaminated soil.

The remediation effect of organic acids in heavy metal contaminated soil was widely studied. However, the comprehensive evaluation of organic acids on micro-ecological environment in heavy metal contaminated soil was less known. Herein, this experiment was conducted to investigate the impact of malic acid, citric acid and oxalic acid on soil fertility, cadmium (Cd) speciation and ecotoxicity in contaminated soil. Especially, to evaluate the ecotoxicity of Cd, high-throughput sequencing was used to investigate the soil bacterial community structure and diversity after incubation with organic acids. The results showed that obvious changes in soil pH were not observed. Whereas, the contents of available phosphorus (Olsen-P) and alkali hydrolysable nitrogen (Alkeline-N) evidently increased with a significant difference. Furthermore, compared to control, the proportion of acetic acid-extractable Cd increased by 3.06-6.63%, 6.11-9.43% and 1.91-6.22% respectively in the groups amended with malic acid, citric acid and oxalic acid, which indicated that citric acid did better in improving the availability of Cd than malic acid and oxalic acid. In terms of biological properties, citric acid did best in bacteria count increase, enzyme activities and bacterial community structure improvement. Accordingly, these results provided a better understanding for the influence of organic acids on the micro-ecological environment in Cd contaminated soil, based on physicochemical and biological analysis.

Antinephrolithiatic activity of Ananas comosus extract against experimentally induced renal calculi in rats.

The present study evaluates the prophylactic role of Ananas comosus ethanolic extract (ACEE) against sodium oxalate (NaOx) - induced nephrolithiasis. Forty two rats were allocated into the following set of groups (6 rats/set group). Normal rats divided to two groups, one of them received distilled water (Control group) and the other received ACEE (1000 mg/kg body weight, p.o) for 7 consecutive days. Urolithiatic rat groups which divided into five subgroups injected with sodium oxalate (70 mg NaOx /kg body weight, i.p) for 7 days; and concurrently received oral administration of distilled water (Urolithiatic group, Vehicle), ACEE and Cystone. Interestingly, ACEE showed a beneficial effect in preventing stone formation. Significant reductions were obtained in the urinary and serum calcium and phosphate excretion along with an increase in magnesium excretion in urolithiatic rats treated with ACEE. Urolithiatic rats treated with ACEE and cystone significantly increased the urinary volume. Administration of ACEE caused significant amelioration in renal function which suggests antilithiatic activity of ACEE. Moreover, urolithiatic rats treated with ACEE significantly attenuated oxidative damage induced by NaOx. In conclusion, ACEE has antilithiatic efficacy may be due to its diuretic activity, antioxidant activity, beside its bioactive constituents which affecting calcium oxalate crystallization.

A long-term evaluation of experimental potassium oxalate concentrations on dentin hypersensitivity reduction: A triple-blind randomized clinical trial.

OBJECTIVE: The aim of this split-mouth, triple-blind, randomized clinical trial was to evaluate the long-term clinical efficacy of experimental potassium oxalate concentration (10%) in relieving dentin hypersensitivity (DH), after a four-session application protocol. METHODS: Potassium oxalate gels with different concentrations (5 and 10%) were randomly assigned to half of the 31 patients from the sample in a split-mouth design. The desensitizers were applied following a four-session protocol, one session every 48 h. The primary outcome was the assessment of pain level with the visual analog scale (VAS, 0-10), at baseline, immediately after each desensitizing session, and also after the seventh day and along 1-,3-, 6-, 9- and 12-months follow-ups. Statistical analyses were performed using Friedman repeated measures and Wilcoxon signed rank tests (α = 0.05). RESULTS: For both groups, the minimum of three sessions were required for the achievement of lower DH levels. Regardless of the concentration, the desensitizing effect was maintained all the way to the end of the 6-month follow-up. The 10%-potassium oxalate group was more effective for both 9 and 12-months follow-up periods (p < 0.001). No complications and adverse effects were observed. CONCLUSIONS: When a four-session protocol is applied, both concentrations of potassium oxalate (5 and 10%) proved to be effective on DH reduction for up to six months. However, the higher concentration promoted better long-term results. CLINICAL SIGNIFICANCE: The DH is an increasing condition in clinical practice, which affects the patient's life quality. This study provides primary clinical evidence, suggesting that multiple application sessions and higher concentrations of potassium oxalate may result in maintenance of the desensitizing effect for more extended periods. Trial registered under number: ClinicalTrials.gov NCT03083496.

Oxalic acid preharvest treatment increases antioxidant systems and improves plum quality at harvest and during postharvest storage.

BACKGROUND: Plums are much appreciated by consumers as fresh fruit but have a limited storage life. Since reactive oxygen species (ROS) are associated with fruit ripening, an increase in ROS scavenging antioxidant systems could lead to a delay in postharvest plum ripening and in maintaining fruit quality after long cold storage. RESULTS: Results showed that crop yield (kg per tree) and fruit weight were enhanced by preharvest oxalic acid (OA) treatment of plum cultivars ('Black Splendor' and 'Royal Rosa'), although the on-tree ripening process was delayed. In addition, the ripening process during cold storage was delayed in plums from OA-treated tress, manifested by lower firmness and acidity losses and reduced ethylene production, as compared with fruits from control trees. Antioxidant compounds (phenolics, anthocyanins and carotenoids) and the activity of antioxidant enzymes were higher in plums from OA-treated trees than in controls, at harvest and during 50 days of cold storage. CONCLUSION: OA preharvest treatment could be a useful tool to maintain plum quality properties during long-term storage, by delaying the postharvest ripening process through a delay in ethylene production, with an additional effect on increasing bioactive compounds with health beneficial effects. © 2018 Society of Chemical Industry.

Influence of recurrent rainfall and oxalic acid on phosphorus releasing from rocks phosphate in the Chaohu watershed, China.

In order to understand the spatial distribution characteristics, loss risk and leaching behaviors of phosphorous from exposed rocks in typical small-area of Chaohu watershed, phosphorus-rich rock was selected for conducting a series of column leaching experiments to investigate the phosphorus leaching. By simulating the intermittent cycle of acid rainfall, effects of oxalic acid on the weathering of phosphate rocks were studied. Total phosphorus contents, pH and phosphate leaching capacity from phosphorus rocks were tested in the presence of oxalic acid at different dry-wet intervals. The results indicated that the cumulative release of phosphorus increased first and then decreased with the duration of dry-wet intervals increasing. Four typical kinetic equations can describe phosphorus release from phosphate rocks with the action of oxalic acid. The best fitting models were the weight function and parabolic equation, with a mean correlation coefficient R2 of 0.9727 and 0.9941, respectively, which reached significance level. Total phosphorus (TP) leaching distribution in each column showed a tendency of gradually decreasing from top to bottom except for time interval of 5 d and 7 d. Occluded-bound P (Oc-P) is the dominant form in rocks. The change point value of rocks phosphorus is 4.11  mg kg-1 after intermittent leaching, and the phosphorus loss risk is relatively large in some rocks formations.

Inhibitory mechanism and molecular analysis of furoic acid and oxalic acid on lipase.

Lipase hydrolyzes fat to free fatty acid and monoacylglycerol, which can be absorbed. Lipase inhibitors reduce the absorption of fat by intestinal cells. In this paper, we explored a novel treatment for obesity. Lipase was strongly inhibited by furoic acid and oxalic acid (IC50 of 2.12 ±â€¯0.04 and 15.05 ±â€¯0.78 mM, respectively). The inhibition by furoic acid was non-competitive, while that of oxalic acid was competitive (inhibition constant 2.12 ±â€¯0.04 and 10.6 ±â€¯0.17 mM, respectively). Quenching was static. With increasing concentration of inhibitor, the peaks of enzyme fluorescence declined. Docking results suggested that furoic acid and oxalic acid could interact with the amino acid residues of the active center of lipase.