H2O2 Peroxidation Research Articles

Exploring the Protective and Reparative Mechanisms of G. lucidum Polysaccharides Against H2O2-Induced Oxidative Stress in Human Skin Fibroblasts.

BackgroundGanoderma lucidum (G. lucidum) is one of China’s traditional medicinal materials. G. lucidum polysaccharide has a wide range of promising pharmacological applications. However, there are many kinds of G. lucidum and they contain different kinds of polysaccharides. The biological mechanism through which Ganoderma lucidum polysaccharides (GLP) is able to protect human skin fibroblasts (HSFs) from H2O2-induced oxidative damage is still unclear.MethodsSix polysaccharides were obtained from G. lucidum to evaluate their free radical scavenging ability (DPPH free radical, ABTS free radical, hydroxyl-free radical, superoxide anion-free radical) in vitro, and their protective and reparative effects on oxidative damage induced by H2O2 in human skin fibroblasts. One polysaccharide was selected to detect oxidative damage markers and gene expression in the Keap1-Nrf2/ARE signaling pathway in HSFs.ResultsAll six polysaccharides showed the ability to scavenge free radicals and enhance the tolerance of human skin fibroblasts to H2O2 damage. Among them, GLP1 was selected and separated into two components (GLP1I and GLP1II). The results showed that GLP1, GLP1I and GLPII could significantly reduce the levels of reactive oxygen species (ROS) and malondialdehyde (MDA). The protective effect of GLP1II was stronger than that of positive control vitamin C. In addition, GLP1, GLP1I and GLP1II could significantly increase the levels of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px). And GLP1I works best in both ways. Meanwhile, Nrf2, a key regulator of keAP1-NRF2/ARE signaling pathway, was activated, while Keap1, a negative regulator, was inhibited, thus promoting the expression of downstream antioxidant enzyme genes (GSTs, GCLs, Nqo1, and Ho-1).ConclusionThe results showed that GLP could protect human skin fibroblasts from oxidative damage caused by H2O2 peroxide by enhancing enzyme activity and activating Keap1-Nrf2/ARE signaling pathway. GLP will act as a natural antioxidant to protect the skin from oxidative stress damage.

Protective Role of Vitamin B1 in Doxorubicin-Induced Cardiotoxicity in Rats: Focus on Hemodynamic, Redox, and Apoptotic Markers in Heart.

Up until now, the specific mechanisms involved in doxorubicin (DOX)-induced cardiotoxicity have not been fully elucidated. Since thiamine deficiency is associated with myocardial dysfunction and it may lead to cardiomyopathy, we aimed to investigate whether thiamine (Vitamin B1) treatment provides cardioprotection and modulates DOX mediated subchronic cardiotoxicity as well as to determine possible mechanisms of its effects. The study involved 48 Wistar albino rats divided into four groups: healthy non-treated rats and healthy rats treated with thiamine and DOX rats without treatment and DOX rats treated with thiamine. DOX was applied as a single i.p.injection (15mg/kg), while thiamine treatment lasted 7days (25mg/kg/dayi.p.). Before and after the treatment hemodynamic changes were monitored in vivo by echocardiography. When the protocol was completed, animals were sacrificed and rat hearts were isolated in order to evaluate parameters of cardiac oxidative stress [superoxide anion radical-O2−, hydrogen peroxide-H2O2, nitric oxide-NO−, index of lipid peroxidation-thiobarbituric acid (TBA) reactive substances (TBARS), superoxide dismutase – SOD, catalase (CAT), and reduced glutathione-GSH] and apoptosis (Bax, Bcl-2, caspases). DOX treatment significantly reduced the ejection fraction, while thiamine treatment led to its minor increase in the DOX-treated group. In that sense, heart oxidative stress markers were significantly increased in DOX-treated rats, while therapeutic dose of thiamine decreased the levels of free radicals. Our study demonstrated the promising ameliorative effects of thiamine against DOX-induced cardiotoxicity through modulation of oxidative stress, suppression of apoptosis, and possibility to improve myocardial performance and morphometric structure of rats` hearts.

Drought‐induced increase in catalase activity improves cotton yield when grown under water‐limiting field conditions

AbstractPlants experiencing abiotic stress can produce excessive reactive oxygen species (ROS), ultimately impacting the crop growth and yield. Hydrogen peroxide H2O2 is a relatively stable active ROS and is mainly scavenged by catalase. In this study, the catalase‐encoding E. coli KatE gene was transferred to cotton plants by Agrobacterium‐mediated transformation. From almost 100 independent transgenic lines, three transgenic lines were identified that did not display a discernible growth and yield phenotype when grown under well‐watered field conditions, but were tolerant to drought under field conditions, resulting in a ~ 25% higher cotton‐seed yield. The three lines were analysed under controlled laboratory conditions to explain the drought‐dependent phenotype: the transgenic lines displayed drought‐inducible EcKatE expression and total catalase activity was only higher than that of the wild type during growth under drought or salinity stress. Furthermore, drought‐induced ectopic EcKatE expression increased total SOD and POD activities, decreased H2O2 levels and improved photosystem II performance and relative water content. The results show that ectopic EcKatE expression displays an advantage during drought stress, without negatively affecting yield during well‐watered field conditions. EcKatE overexpression confers hyper‐resistance to drought in cotton and provides improved cotton‐seed yield under water‐limiting field conditions. And the EcKatE gene might also be a promising drought‐resistant gene for improving other crop varieties.

The nanoparticles zero-valent synthesis by black tea extract to remove rb 238 using synthetic and natural wastewater by packed bed reactor

This study aims to synthesize nanoparticles of iron zero valences from black tea (BT-NZVI) and bentonite supported with black tea zero-valent iron (B-BT-NZVI) using black tea extract in an environmentally friendly and sustainable way to remove the reactive blue pigment 238 (RB). 238) from water. The characterization tests for BT-NZVI and B-BT-NZVI were performed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The zeta potential in the stability of iron nanoparticles was also measured. For measuring the porous material’s surface area, the Brunaune Emmett-Teller (BET) method was used the average diameter of iron nanoparticles was less than 50 nm. BT-NZVI and B-BT-NZVI were used as absorbents in the batch system study. Two adsorption balance models, Langmuir and Freundlich, are used to describe the adsorption process. The Freundlich model matches well with Reactive Blue 238 dye data and has proven successful in the adsorption process. Kinetic data acquired using the pseudo-first and pseudo-second model examined under optimal reaction conditions and a variety of NZVI concentrations. both batch and up-flow packed flow bed reactor with peroxide H2O2 can degrade dyes and utilized in industrial wastewater treatment.

Foliar application of H2O2 as salt stress attenuator in ‘BRS Rubi do Cerrado’ sour passion fruit

Irrigation with saline water causes a reduction in yield, especially in semi-arid regions. Cultivation strategies have been developed to mitigate salt stress on plants, such as the use of hydrogen peroxide. The objective of this study was to evaluate the attenuating effect of hydrogen peroxide on the gas exchange and growth of ‘BRS Rubi do Cerrado’ sour passion fruit cultivated under irrigation with saline water. The design was completely randomized in split-plot plots, with water salinity levels ECw (0.6, 1.2, 1.8, 2.4, and 3.0 dS m-1) considered the plots and the concentrations of hydrogen peroxide H2O2 (0, 15, 30, and 45 μM) considered the subplots, with three replicates. Gas exchange (stomatal conductance, transpiration, CO2 assimilation rate, intercellular CO2 concentration, instantaneous water use efficiency, and instantaneous carboxylation efficiency), and absolute and relative growth rates in stem diameter were evaluated. An increase in irrigation water salinity from 0.6 dS m-1 reduced gas exchange, and exogenous application of hydrogen peroxide did not promote a significant effect on gas exchange. However, foliar application of hydrogen peroxide at 15 μM increased the growth of ‘BRS Rubi do Cerrado’ sour passion fruit.

Physio-Anatomical Study of Polyploid Watermelon Grafted by Different Methods

Watermelon is one of the most desirable vegetable crops in the world. Recently, grafting is common in watermelons worldwide, but not all grafting methods are compatible with polyploids. In this study, diploid, triploid, and tetraploid from one watermelon variety, “Mi Mei”, were grafted on the “Xijiaqiangsheng” squash rootstock to study the effect of genome duplication on graft compatibility. Three grafting methods (splice, hole, and tongue) were used to determine graft compatibility. Significant differences in survival rates, hormones, antioxidants (AOX), sugars, and starch contents were observed between compatible/incompatible combinations. Compatible combinations with high survival rates showed high levels of hormones, AOX, carbohydrates, and low hydrogen peroxide H2O2 compared to incompatible plants. The hole grafting method was more efficient with diploid, while splice was efficient with a tetraploid, and both methods can be used for triploid. Compatibility is a combined effect of hormone, carbohydrate, and antioxidant activities. We predict that compatibility is a complex process and that further molecular studies must be performed to dig deep into this phenomenon.

Salinity induced alterations in photosynthetic and oxidative regulation are ameliorated as a function of salt secretion.

Ion secretion facilitates recretohalophytes to tolerate saline and drought conditions but its relative contribution to the survival of many species remains poorly understood. Tamarix chinensis has high potential for restoration of saline deteriorated lands. The water management and high salt tolerance of the plant have highlighted the need to determine the strategies that govern these mechanisms. Here we report the selectivity of this halophyte to transport, utilize, and secrete different cations and anions under various NaCl (0, 100, 200 and 400mM) concentrations. Plant growth, photosynthesis and antioxidant defense responses were also determined to relate them with the function of ion secretion. Results reflected two different sets of strategies adopted by plants to survive low and high salinities. Exposure to highly saline conditions caused reduction in photosynthesis due to stomatal and biochemical limitations. The decreased content of photosynthetic pigments exposed plants to excessive light energy that accelerated production of ROS (i.e., hydrogen peroxide H2O2) and caused damage to cellular membranes. The increased activities of anti-oxidative enzymes (superoxide-dismutase, catalase, ascorbate-peroxidase, and glutathione-reductase) were insufficient to detoxify H2O2. In contrast, plants treated with low salinity did not face stomatal limitations while the photosynthetic pigments increased. As no damage to membranes was detected, the increased content of H2O2 was postulated for its messenger role. The assimilation of essential nutrients was affected due to increased content of toxic ions (Na+ and Cl-) in the growing medium and within the plants. However, the ability to regulate K+ facilitated plants to improve water use efficiency under hyper-osmotic environment. The removal of toxic ions from the photosynthesizing tissues demands high energy, which was evident in the compromised growth of plants. This study offers a window to physiological mechanisms, e.g., potassium retention that ensure salt secretion as a beneficial strategy for prolonged survival of T. chinensis.

Study of the effectiveness of hydrogen peroxide in improving the germination characteristics of maize seed under water stress

"A factorial experiment was carried out in the lab. college of Agricultural Engineering Science, University of Baghdad Al- Jadiriyah during year of 2017 With the aim of improving the germination properties of Maize variety of Noor under water stress. According to the Completely randomize design (CRD) with three replications were used in both and two factors: first: it included water tensile treatments by exposing the seeds to a solution of polyethylene glycol PEG 6000 with three levels (0, -4 ,-8) Bar, while the second factor with three concentrations of the compound peroxide Hydrogen H2O2 with a concentration of 50% (0, 10 , 20 mg L-1). The results showed that water stress had a significant effect on the characteristics of Maize seedlings, as it reduced the level of water stress (-8) bar, the average germination percentage, Average 80.00%, Root Shoot length, 7.900 , 5.22 (cm), respectively, seedling dry weight 269.9 (mg seedlings-1) and Seed vigor index of drought resistance 0.781,while treatment with compound hydrogen peroxide H2O2 contributed to improving the characteristics of Maize seedlings significantly, as the seed soaking treatment at a concentration of 20 (mg L-1) recorded the highest germination rate of 89.44%, the feather length of 5.90 (cm), and the seedling dry weight 353.6 (mg seedlings-1). Germination and vigor index of drought resistant 1.089. We recommend to soak maize seeds with peroxide Hydrogen H2O2 (10 ) mg L-1 for 24 h before planting, especially under water stress."

The Effect of Alcoholic Extract of Rhizomes of Greater Galangal (Alpinia galanga L.) on the Serum Antioxidant Enzymes for Japanese Quail During Oxidative Stress Induced by Hydrogen Peroxide

This study aimed to investigate the effect of alcoholic extract of greater galangal rhizomes on the serum antioxidant enzymes level in Japanese quail during oxidative stress induced by hydrogen peroxide. Two hundred and sixteen, 7 days-old of Japanese quail birds were randomly distributed into four groups (n=54) with three replicates per group and 18 chicks per replicate. The groups as follows: the first group was drank water without any addition as control. The second group was supplied with 4 ml.-1 hydrogen peroxide H2O2 (40%). The third group was supplied with 4 ml.-1 both hydrogen peroxide (40%) and alcoholic extract of greater galangal rhizomes. The fourth group was supplied with 4 ml.-1 alcoholic extract of greater galangal rhizomes. The results showed the lowest significant (P<0.05) decrease of malonaldehyde (MDA), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) concentrations in the fourth group while, the highest significant (P<0.05) increase was recorded in the second group. The highest significant (P<0.05) activity level of superoxide dismutase (SOD) and glutathione peroxidase (GPx) recorded in the fourth group, on the other hand, it was significantly lowest in the second group. The results explained there is no significant difference (P<0.05) in the concentration of MDA,SOD, GPx AST and ALT between the first (control) and third groups. The results indicated there is no significant differs between males and females in the MDA,SOD, GPx AST and ALT. It can be concluded, oxidative stress was caused a negative impacts on serum SOD, GPx. AST and ALT enzymes. Moreover, it was caused an increase in MDA levels. The alcoholic extract of rhizomes of greater galangal was reduced and reversed the H2O2 impacts. All parameters non-significantly influenced by sexes.

Analytical study of the intensification of the mass transfer process during inactivation of soybean grain in an ultrasonic installation

The article is devoted to improving the effectiveness of technological impact on soy in order to remove anti – nutritional substances from it-trypsin inhibitors and urease enzymes. This is achieved by intensifying the mass transfer during extraction by ultrasonic pulsating micro-flows and cavitation with the formation of the oxidizer hydrogen peroxide H2O2. The developed technical means provide high inactivation rates and increase the productivity of the process.

INDUCED SEED TREATMENT WITH HYDROGEN PEROXIDE (H2O2) PROMOTES PHYSIOLOGICAL, BIOLOGICAL CHANGES AND SALT-TOLERANCE IN WHEAT (TRITICUM AESTIVUM L.)

The present study was undertaken to study the effect of exogenously applied six hydrogen peroxide H2O2 concentrations (0, 20, 40, 60, 80 and 100 µM) as seed primer on two wheat varieties (Khirman and Inqalab) under salt and non-salt water levels (0 and 100 mM NaCl). The oxidizing effects were measured and estimated using the wheat index of different salt and non-salt water levels, as well as H2O2 soaking seed at varying fixations and concentrations. The H2O2 as a seed primer impacted on growth, yield and physiological and biochemical aspects such as moisture content, sodium potassium substance and sodium potassium content under H2O2 and NaCl levels. The results revealed that the exogenous application of hydrogen peroxide was effective in increasing tolerance of wheat under salt stress. The Khirman and Inqalab varieties could be established and cultivated under saline conditions. 60?M treatment of H2O2 is seen with the strongest impacts. Progress has contributed to enhance physiological and biochemical features of stress outflow, which promote growth.

Correlates of Early-Stage Frailty—Sleep, Fitness, Oxidative Stress, and BMI

Frailty reflects a decreased reserve in multiple systems resulting from cumulative decline. Frailty markers should be identified as early as possible to attenuate the loss of reserve. The aim of this study was to identify potentially modifiable correlates of frailty in relatively healthy older adults. Volunteers (n = 122) were recruited from local councils and, based on gender and age, were divided into one group of men aged 77.0 (±5.3), and two groups of women, aged 68.8 (±3.6) and aged 78.4 (±3.4). Frailty was assessed by a Frailty Index. The examined correlates were: physical activity, physical fitness (predicted peak VO2), sleep quality, oxidative stress (hydrogen peroxide—H2O2) and depression. Both groups of women had poor scores on physical fitness compared to women's norms. In order to examine the contribution of each of the potential correlates to explaining the variance of frailty, stepwise regressions were performed for each group separately. Based on the results, none of the suggested correlates significantly explained the variability of frailty in the men. In the younger-aged women, predicted peak VO2 and sleep quality explained 22.4% of the variability of frailty. In the older women, Body Mass Index (BMI), oxidative stress and sleep quality explained 34.9% of the variance. It is possible that increased aerobic fitness and interventions for improving sleep quality in older, seemingly healthy women will slow down the frailty process. Further research is needed to assess potential correlates of frailty, and to initiate suitable interventions to mitigate the signs of frailty at an early stage.

Study of the Efficiency of Sludge Conditioning by the Method of Advanced Oxidation Process (AOP) During Dewatering of Excess Activated Sludge

The issue of sludge disposal is a complex task that needs to be addressed, taking into account not only economic indicators but also local conditions, such as: the availability of existing sewage treatment plant infrastructure, energy availability, climatic conditions and so on. Currently, more and more municipal enterprises in European countries are building sludge incineration plants. Preparation of sludge for incineration occupies a significant part of the budget since its humidity and caloric content have the greatest impact on the parameters of the sludge incineration unit and its energy balance. Chamber-membrane filter presses are one of the few types of equipment that allows to ensure the maximum reduction of sludge moisture, and the possibility of its completion with heat treatment systems in one closed housing make it an even more attractive solution for small and medium wastewater treatment plants. Of great interest at the present stage of development of wastewater treatment and sludge disposal technology is the technology of advanced oxidation of AOR, which allows to remove biologically stable organic pollutants and leads to inactivation of pathogenic microorganisms. The purpose of this stage was to evaluate the possibility of using the technology of advanced oxidation of AOP for conditioning sludge of municipal treatment plants before their mechanical dehydration and to determine the technological parameters of the sludge filtration process. The studies included laboratory and industrial tests. Based on the research, it was found that AOP technology can be used to reduce the consumption of reagents (iron, lime) in the conditioning of municipal sewage sludge in the case of filtration on a chamber-membrane filter press. The most economically and technologically optimal ratio of Fe / Ca / H2O2 is equal to 2/5/1 at the dosage of hydrogen peroxide H2O2 at the level of 1 g / l. At the proposed dosages of reagents, it is possible to obtain a filtration sludge with a residual moisture content of 64–65% compared to 72–73% using only iron and lime (initial dry matter content in the sludge at 3%).

Determination of an effective method of Citrus aurantifolia lime and Citrus lemon varieties plant explants sterilization for in vitro introduction into the culture

Potted citrus plants are in constant demand, but the propagation of such plants requires the use of a winter greenhouse and several well-developed mother plants to obtain planting material. The use of microclonal propagation can accelerate the production of seed material though it requires detailed development of in vitro cultivation techniques. The aim of the research was to study the effectiveness of sterilizing substances and methods of sterilization on the yield of viable micro shoots of lime plants (Citrus aurantifolia) as well as Meyer and Jubilee lemon varieties and their growth in vitro. The research was conducted in the interdepartmental "Biotechnological Laboratory" of the Agrobiotechnological Faculty of Bila Tserkva NAU. The source material was microshoots from lime plants (Citrus aurantifolia), and lemon varieties (Citrus lemon) Meyer and Jubilee. The objects of the study were selected according to the diversity of genotypes, development type and varietal characteristics. The possibility of using different parts of plants for reproduction is a feature of in vitro culture. We used microshoots with a bud in our research. To neutralize the exogenous bacterial and fungal microflora, we used 70 % ethanol solution C2 H5 OH, sodium hypochlorite 5 %, 15 % solution of hydrogen peroxide H2 O2 , sulema (0.1) and washed the material in sterile water (for 5–10 min) under several schemes. The study revealed the influence of different sterilization regimes for obtaining sterile explants and the introduction into plant culture of explants of the species of lime Citrus aurantifolia as well as Meyer and Jubilee lemon varieties. It was found that the use of step sterilization using 2.5 % solutions of sodium hypochlorite gives a high percentage of sterile viable material – 27.7 %, which is significantly higher than in other variants of the experiment. Key words: microshoots, lime, sterile material, micropropagation, sterilization, hydrogen peroxide, viability of explants.

Cytogenetic effects of antidiabetic drug metformin

Metformin (MET) is the first-choice antidiabetic drug for type 2 diabetes mellitus treatment. In this study, the genotoxic potential of MET was evaluated by using chromosome aberrations (CAs), sister chromatid exchanges (SCEs), and micronucleus (MN) assays in human peripheral lymphocytes as well as comet assay in isolated lymphocytes. Human lymphocytes were treated with different concentrations of MET (12.5, 25, 50, 75, 100, and 125 µg/mL) for 24 h and 48 h. A negative and a positive control (Mitomycin-C-MMC, 0.20 μg/mL, for CA, SCE, and MN tests; hydrogen peroxide-H2O2, 100 µM, for comet assay) were also maintained. MET significantly increased the frequency of CAs at 48 h exposure (except 12.5 µg/mL) compared to the negative control. MET increased SCEs/cells in both treatment periods (except 12.5 µg/mL at 24 h). MET only increased the frequency of MN at 125 µg/mL. While MET significantly increased the comet tail length (CTL) at four concentrations (25, 75, 100, and 125 µg/mL), it did not affect comet tail intensity (CTI) (except 125 µg/mL) and comet tail moment (CTM) at all the treatments. All these data showed that MET had a mild genotoxic effect, especially at a long treatment period and higher concentrations in human lymphocytes in vitro. However, further in vitro and especially in vivo studies should be conducted to understand the detailed genotoxic potential of MET. Highlights Metformin increased the frequency of CAs and SCEs, especially at 48-h exposure time in human lymphocytes. This antidiabetic drug increased the frequency of MN only at the highest concentration tested (125 µg/mL). Metformin significantly increased the comet tail length in all treatments (except 50 µg/mL). The drug did not significantly affect the comet tail intensity (except 125 µg/mL) and comet tail moment in all treatments.

Dual-Mode Solution Plasma Processing for the Production of Chitosan/Ag Composites with the Antibacterial Effect.

The development of novel biocompatible and biodegradable materials for medical applications has been drawing significant interest in the scientific community for years. Particularly, chitosan loaded with silver nanoparticles (Ag NPs) has a strong antimicrobial potential and could be applied, for example, as wound dressing material. In this work, chitosan/Ag NP composites were produced utilizing a single-step plasma-solution process, which is simple and environmentally friendly. An acetic solution of chitosan containing AgNO3 was treated by the direct current (DC) atmospheric pressure glow discharge, with the liquid serving as either cathode or anode. The plasma-solution system with liquid anode is more useful for the production of Ag NPs. Nevertheless, the NP size is comparable for both cases. The plasma treatment with both polarities led to chitosan degradation. The cleavage of glucosidic chains mostly occurred in the system with the liquid cathode, whereas the side oxidation reactions took place when the solution served as the anode. The oxidation processes were possibly induced by the hydrogen peroxide H2O2 efficiently formed in the last case. The composite materials produced with both polarities of liquid electrode demonstrated the bactericidal action against Gram-negative Escherichia coli, Gram-positive Staphylococcus aureus, and Gram-positive Bacillus subtilis.

EFFECT OF SPRAYING WITH SALICYLIC ACID AND HYDROGEN PEROXIDE ON SOME QUALITY PROPERTIES OF FRUITS OF THREE VARIETIES OF DATE PALM TREES Phoenix dactylifera L. PROPAGATED VIA TISSUE CULTURE

The experiment was conducted at the AL-Kut Date Palms Station of Horticulture Department and the Ministry of Agriculture for 2019 season with the aim of studying the effect of spraying with salicylic acid (SA) and hydrogen peroxide H2O2 (Control 0%, SA 250 and 500 mg L-1, H2O2 at a concentration of 3% and 6%) on three cultivars (Barhi, Hilali and Majhool) of propagated via tissue culture and the interaction between them in some qualities properties of the fruits, the research was carried out as a factorial experiment with the design of complete random sectors (RCBD) and with three replicates. The results showed when using the SA 500 and 250 mg.L-1led To increase the percentage of total sugars amounted to 60.58% and 59.22 respectively, outperforming the rest of the coefficients Spraying and reducing sugars decreased when using spray transactions compared to control treatment, while the percentage rose sucrose in most transactions spray. When using H2O2, 6% increase the percentage of total soluble solids by 64.32% and decreased the percentage of fruit fall to 4.78%. The cultivars did not differ significantly in their content of total and reducing sugars and sucrose, while the Majhool and the Barhee significantly 65.56 and 64.61 compared to Hilaly 49.08 in the percentage percentage of the total soluble solids, whereas the Majhool significantly outperformed in the weight of the pulp of the soft fruit 22.43 g. Fruit -1

A Review on Antibacterial Properties of Biologically Synthesized Zinc Oxide Nanostructures

Anti-bacterial activity of biologically synthesized zinc oxide (ZnO) nanostructures has engrossed great attention around the globe due to distinctive nanotechnological applications. Biogenic ZnO nanostructures have prominent anti-bacterial properties as compared to bulk because small sized nanostructures exhibit larger surface area leading to improved particle surface-reactivity. This study reveals that biologically synthesized ZnO nanostructures are bio-compatible, stable and have longer shelf life due to presence of phytochemicals which acts as stabilizing and capping agents during synthesis process. The anti-bacterial mechanism of ZnO nanostructures includes production of reactive oxygen species (ROS) such as hydrogen peroxide H2O2, OH− and O2−2. The ROS provides major toxicity mechanism which includes destruction of cell wall due to interaction of ZnO nanostructures. Sometimes, ZnO nanostructures have increased anti-bacterial activity due to surface imperfections and ROS generation in dark. Interaction between ZnO nanostructures and bacterial cell causes mitochondrial weakness, intra-cellular outflow, and oxidative stress which eventually inhibits bacterial growth and kills the whole cell. This review describes anti-bacterial activity of biologically synthesized ZnO nanostructures by previously reported literature and tests used to examine anti-bacterial activity, influence of UV illumination, ZnO unique features i.e. size, concentration, morphology, and defects. Furthermore, it also presents significant anti-bacterial applications of ZnO nanostructures particularly in food packaging industry, pharmaceutical industry and other health care applications.

Postharvest 1-methylcyclopropene application delays leaf yellowing of pak choi (Brassica rapa subsp. chinensis) by improving chloroplast antioxidant capacity and maintaining chloroplast structural integrity during storage at 20 °C

The aim of this study was to uncover the regulatory mechanism underlying the leaf yellowing of pak choi after 1-methylcyclopropene (1-MCP) treatment at (20 ± 0.5) °C. The ultrastructural, physiological and biochemical metabolism changes of the chloroplast in pak choi were investigated. Chlorophyll degradation was effectively alleviated by 1-MCP treatment, and the market life of pak choi was extended by 2 days compared with that of control. Electron microscopy confirmed that the chloroplast breakdown was reduced by 1-MCP. This treatment not only preserved the high activities of chloroplast antioxidant enzymes (superoxide dismutase SOD and ascorbic peroxidase APX) and non-enzymatic antioxidants (ascorbate-glutathione (AsA-GSH)) for scavenging reactive oxygen species (ROS) (superoxide anion O2·− and hydrogen peroxide H2O2), but also decreased the chloroplast chlorophyll-degrading peroxidase (Chl-POX) activity, thus retarding chlorophyll degradation in the peroxidase-H2O2 system. Abundant O2·- and H2O2 may function as major toxic molecules to enhance the activities of chloroplast phospholipase (PLD), lipoxygenase (LOX) and lipase. The loss of the chloroplast structural integrity and function caused by the high activities of PLD, lipase and LOX aggravated the enzymatic degradation of chlorophyll in pak choi, which was rescued by using 1-MCP that retarded the degradation of the chloroplast membrane, as well as maintained high unsaturated fatty acid levels and low malondialdehyde (MDA) level. In conclusion, 1-MCP fumigation may augment the chloroplast antioxidant capacity for scavenging ROS (O2·- and H2O2), which attenuated the activities of chloroplast PLD, lipase and LOX, inhibited the degradation of the chloroplast membrane and kept the membrane integrity and normal function, ultimately relieving the yellowing of pak choi.

Keggin-Type Mixed Polyoxomolybdates Catalyzed Cyclohexanone Oxidation by Hydrogen Peroxide: In Situ IR Pyridine Adsorption

Homogenous cyclohexanone oxidation was catalyzed by a series of Keggin-type polyoxometalates as formula H3PMo12O40, Cs3PMo12O40, CsSnPMo12O40, Cs2Sn0.5PMo12O40 and HSnPMo12O40 using hydrogen peroxide H2O2 (30%), without solvent. The following reaction products, adipic, glutaric and succinic acids, butane-1,3-diol and e-caprolactone were identified and quantified by high-performance liquid chromatography (HPLC). The catalysts were prepared and characterized by Fourier transform infrared spectroscopy (FTIR), chemical analysis (ICP), 31P and 133Cs nuclear magnetic resonance spectroscopies and in situ FTIR of pyridine adsorption. The presence of both BrOnsted and Lewis acid sites was evidenced for CsSnPMo12O40, Cs2Sn0.5PMo12O40 and HSnPMo12O40. Among them, HSnPMo12O40 exhibited total conversion with adipic acid, as major product (60% of yield).