H2O2 Pretreatment Research Articles

Hydrogen Peroxide Pretreatment Mitigates Cadmium-Induced Oxidative Stress in Brassica napus L.: An Intrinsic Study on Antioxidant Defense and Glyoxalase Systems.

Cadmium (Cd) is considered as one of the most toxic metals for plant growth and development. In the present study, we investigated the role of externally applied hydrogen peroxide (H2O2) in regulating the antioxidant defense and glyoxalase systems in conferring Cd-induced oxidative stress tolerance in rapeseed (Brassica napus L.). Seedlings were pretreated with 50 μM H2O2 for 24 h. These pretreated seedlings as well as non-pretreated seedlings were grown for another 48 h at two concentrations of CdCl2 (0.5 and 1.0 mM). Both the levels of Cd increased MDA and H2O2 levels and lipoxygenase activity while ascorbate (AsA) declined significantly. However, reduced glutathione (GSH) content showed an increase at 0.5 mM CdCl2, but glutathione disulfide (GSSG) increased at any level of Cd with a decrease in GSH/GSSG ratio. The activities of ascorbate peroxidase (APX) and glutathione S-transferase (GST) upregulated due to Cd treatment in dose-dependent manners, while glutathione reductase (GR) and glutathione peroxidase (GPX) increased only at 0.5 mM CdCl2 and decreased at higher dose. The activity of monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), catalase (CAT), glyoxalase I (Gly I), and glyoxalase II (Gly II) decreased under Cd stress. On the other hand, H2O2 pretreated seedlings, when exposed to Cd, AsA and GSH contents and GSH/GSSG ratio increased noticeably. H2O2 pretreatment increased the activities of APX, MDHAR, DHAR, GR, GST, GPX, and CAT of Cd affected seedlings. Thus enhancement of both the non-enzymatic and enzymatic antioxidants helped to decrease the oxidative damage as indicated by decreased levels of H2O2 and MDA. The seedlings which were pretreated with H2O2 also showed enhanced glyoxalase system. The activities of Gly I, and Gly II and the content of GSH increased significantly due to H2O2 pretreatment in Cd affected seedlings, compared to the Cd-stressed plants without H2O2 pretreatment which were vital for methylglyoxal detoxification. So, the major roles of H2O2 were improvement of antioxidant defense system and glyoxalase system which protected plants from the damage effects of ROS and MG. The mechanism of H2O2 to induce antioxidant defense and glyoxalase system and improving physiology under stress condition is not known clearly which should be elucidated. The signaling roles of H2O2 and its interaction with other signaling molecules, phytohormones or other biomolecules and their roles in stress protection should be explored.

Impact of pre-oxidation using H2O2 and ultraviolet/H2O2 on disinfection byproducts generated from chlor(am)ination of chloramphenicol

Hydrogen peroxide with and without activation by ultraviolet irradiation (UV/H2O2 and H2O2, respectively) has been investigated to degrade emerging contaminants in drinking water. The antibiotic chloramphenicol (CAP) and its analogues (thiamphenicol and florfenicol), referred to collectively as CAPs, can produce a range of disinfection by-products (DBPs) during chlorination or chloramination (chlor(am)ination). The impact of unactivated and activated H2O2 pre-oxidation on the formation of nitrogenous and carbonaceous DBPs from the chlor(am)ination of CAP model precursors was investigated. A theoretical estimated toxicity evaluation was also carried out based on the DBPs that formed. H2O2 pretreatment alone did not affect organic carbon and nitrogen concentrations, but significantly reduced the formation of trichloromethane (TCM) during chlorination and trichloronitromethane (TCNM) during chloramination, and enhanced dichloroacetonitrile (DCAN) yields during chloramination. These significant changes in DBP yields caused by H2O2 pre-oxidation are attributable to the transformation of the three CAPs into more reactive precursor structures. The three CAPs did not form DCAN and TCNM during chlorination, regardless of whether H2O2 pre-oxidation was used. However, UV/H2O2 pretreatment resulted in the unexpected formation of TCNM during chlorination. Furthermore, UV/H2O2 pre-oxidation increased the formation of DCAN and TCNM, whereas it had little effect on TCM formation during chloramination. A preliminary estimated toxicity evaluation demonstrated that UV/H2O2 pre-oxidation at low doses, followed by chlorination, resulted in the lowest estimated toxicity from a range of DBPs. Conversely, the estimated toxicity evaluation showed that unactivated H2O2 (high dose) was preferable to UV activated H2O2 for overall control of these investigated DBPs during chloramination.

Osmopriming-induced salt tolerance during seed germination of alfalfa most likely mediates through H2O2 signaling and upregulation of heme oxygenase.

The present study showed that osmopriming or pretreatment with low H2O2 doses (2mM) for 6h alleviated salt-reduced seed germination. The NADPH oxidase activity was the main source, and superoxide dismutase (SOD) activity might be a secondary source of H2O2 generation during osmopriming or H2O2 pretreatment. Hematin pretreatment similar to osmopriming improved salt-reduced seed germination that was coincident with the enhancement of heme oxygenase (HO) activity. The semi-quantitative RT-PCR confirmed that osmopriming or H2O2 pretreatment was able to upregulate heme oxygenase HO-1 transcription, while the application of N,N-dimethyl thiourea (DMTU as trap of endogenous H2O2) and diphenyleneiodonium (DPI as inhibitor of NADPHox) not only blocked the upregulation of HO but also reversed the osmopriming-induced salt attenuation. The addition of CO-saturated aqueous rescued the inhibitory effect of DMTU and DPI on seed germination and α-amylase activity during osmopriming or H2O2 pretreatment, but H2O2 could not reverse the inhibitory effect of ZnPPIX (as HO inhibitor) or Hb (as CO scavenger) that indicates that the CO acts downstream of H2O2 in priming-driven salt acclimation. The antioxidant enzymes and proline synthesis were upregulated in roots of seedlings grown from primed seeds, and these responses were reversed by adding DMTU, ZnPPIX, and Hb during osmopriming. These findings for the first time suggest that H2O2 signaling and upregulation of heme oxygenase play a crucial role in priming-driven salt tolerance.

Improving Methane Production through Co-Digestion of Canola Straw and Buffalo Dung by H2O2 Pretreatment

In this study an effect of acidic pretreatment on the CS (Canola Straw) and BD (Buffalo Dung) by anaerobic co-digestion was investigated. H2O2 (Hydrogen Peroxide) is a mainly accustomed reagent, used as a bleaching agent in the different industries such as paper and wood. In the present study, it was used as a pretreatment chemical at varying concentrations in batch reactors. The co-digestion of CS and BD was carried out in SAMPTS (Semi-Automatic Methane Potential Test System) at mesophilic (37±1oC) conditions. The CS was pretreated in glass bottles with different concentrations of the H2O2 for seven days. The inoculum used in the present study was an effluent of the CSTR (Continuous Stirred Tank Reactor), which was treating BD at mesophilic conditions. The specific methane production from the codigestion of canola straw and BD, by the pretreatment of H2O2 at concentrations of 0.5, 1.0, and 1.5% were 530.8, 544.5, and 510.3 NmL CH4 g/VS, respectively. The significant reduction in the volatile solids of CS was observed at the optimum pretreatment of 1.0% H2O2.

Improving enzymatic saccharification of cassava stem using peroxide and microwave assisted pre-treatment techniques

The effectiveness of microwave assisted alkali (MAA) and alkaline hydrogen peroxide (AHP) pre-treatment methods in improving the enzymatic saccharification of cassava stem was investigated. Ground cassava stems were by MAA method by varying microwave power, NaOH concentration and pre-treatment time. AHP method was performed at various H2O2 concentrations, pre-treatment temperatures and times. The results showed that reducing sugar yield was higher from MAA pretreated stem when compared with AHP pre-treatment, which demonstrated that MAA pre-treatment was effective in releasing sugars. SEM studies on the pre-treated samples revealed extensive distortion of fibres in MAA pre-treated than AHP pre-treated samples, which showed pores and cracks in the fibrous structure. Spectral studies showed the change in the chemical structure of pre-treated samples. The work revealed that the studied pre-treatment methods were effective in improving the enzymatic saccharification of cassava stem.

Rosmarinic Acid Alleviates the Endothelial Dysfunction Induced by Hydrogen Peroxide in Rat Aortic Rings via Activation of AMPK

Endothelial dysfunction is the key player in the development and progression of vascular events. Oxidative stress is involved in endothelial injury. Rosmarinic acid (RA) is a natural polyphenol with antioxidative, antiapoptotic, and anti-inflammatory properties. The present study investigates the protective effect of RA on endothelial dysfunction induced by hydrogen peroxide (H2O2). Compared with endothelium-denuded aortic rings, the endothelium significantly alleviated the decrease of vasoconstrictive reactivity to PE and KCl induced by H2O2. H2O2 pretreatment significantly injured the vasodilative reactivity to ACh in endothelium-intact aortic rings in a concentration-dependent manner. RA individual pretreatment had no obvious effect on the vasoconstrictive reaction to PE and KCl, while its cotreatment obviously mitigated the endothelium-dependent relaxation impairments and the oxidative stress induced by H2O2. The RA cotreatment reversed the downregulation of AMPK and eNOS phosphorylation induced by H2O2 in HAEC cells. The pretreatment with the inhibitors of AMPK (compound C) and eNOS (L-NAME) wiped off RA's beneficial effects. All these results demonstrated that RA attenuated the endothelial dysfunction induced by oxidative stress by activating the AMPK/eNOS pathway.

SO4= uptake and catalase role in preconditioning after H2O2-induced oxidative stress in human erythrocytes.

Preconditioning (PC) is an adaptive response to a mild and transient oxidative stress, shown for the first time in myocardial cells and not described in erythrocytes so far. The possible adaptation of human erythrocytes to hydrogen peroxide (H2O2)-induced oxidative stress has been here verified by monitoring one of band 3 protein functions, i.e., Cl-/HCO3- exchange, through rate constant for SO4= uptake measurement. With this aim, erythrocytes were exposed to a mild and transient oxidative stress (30min to either 10 or 100μM H2O2), followed by a stronger oxidant condition (300- or, alternatively, 600-μM H2O2 treatment). SO4= uptake was measured by a turbidimetric method, and the possible role of catalase (CAT, significantly contributing to the anti-oxidant system in erythrocytes) in PC response has been verified by measuring the rate of H2O2 degradation. The preventive exposure of erythrocytes to 10μM H2O2, and then to 300μM H2O2, significantly ameliorated the rate constant for SO4= uptake with respect to 300μM H2O2 alone, showing thus an adaptive response to oxidative stress. Our results show that (i) SO4= uptake measurement is a suitable model to monitor the effects of a mild and transient oxidative stress in human erythrocytes, (ii) band 3 protein anion exchange capability is retained after 10 μM H2O2 treatment, (iii) PC response induced by the 10 μM H2O2 pretreatment is clearly detected, and (iv) PC response, elicited by low-concentrated H2O2, is mediated by CAT enzyme and does not involve band 3 protein tyrosine phosphorylation pathways. Erythrocyte adaptation to a short-term oxidative stress may serve as a basis for future studies about the impact of more prolonged oxidative events, often associated to aging, drug consumption, chronic alcoholism, hyperglycemia, or neurodegenerative diseases.

Appropriate mechanical strength of carbon black-decorated loofah sponge as anode material in microbial fuel cells

A new composite anode material, possessing an appropriate mechanical strength, was fabricated by depositing carbon black on the loofah sponge matrix surface. Carbon black was oxidized in nitric acid (HNO3) and hydrogen peroxide (H2O2), respectively, to increase electrochemical properties before starting deposition. Microbial fuel cell (MFC) with the H2O2 treated carbon black anode achieved the maximum power density of 61.7 ± 0.6 W/m3, which was higher than one decorated with the HNO3 treated or untreated carbon black. Scanning electron microscopy (SEM) observation showed a compact bacterial attachment on the H2O2 treated carbon black surface. Results of electrochemical impedance spectroscopy (EIS) and Tafel plots indicated a fast electron transfer rate between the H2O2 pre-treatment of carbon black and electrochemically active bacteria (EAB). Therefore, the H2O2 treated carbon black-loofah sponge anode was promising for MFC application in terms of its superior performance, straightforward fabrication method and ultra-low cost.

164 - To Adapt or Not to Adapt: Sex-Specific and Age-Dependent Adaptation of the Mitochondrial Lon Protease in D. Melanogaster

Mitochondria are central to cellular metabolism. However, an inevitable trade-off is electron leakage, and the resultant generation of superoxide and hydrogen peroxide (H2O2), from the electron transport chain (ETC). To minimize the accumulation of oxidative damage, mitochondria utilize reducing enzymes and repair systems to maintain function, and proteolysis to remove damaged internal proteins. A key mitochondrial-matrix proteolytic enzyme is the nuclear-encoded Lon protease: an ATP-stimulated protein that degrades oxidized proteins. Prior cell culture studies have shown Lon is a stress response protein as measured by its rapidly increased synthesis following exposure to multiple forms of stress: e.g. H2O2, heat shock, and serum starvation. Due to Lon’s role in the maintenance of the mitochondrial proteome, our aim was to study Lon function and stress-responsiveness during aging in the model organism, D. melanogaster. Upon H2O2 stress, females, but not males are capable of adaptation. Females show increased Lon protein expression and activity, which is lost with age. In contrast, males, regardless age or H2O2 pretreatment, show no change in Lon protein expression or activity. These sex-specific differences in stress responsiveness appear to be attributable to expression (or lack of expression) of the mitochondrial Lon protease. In addition, females translate three unique Lon protein isoforms, whereas only two are present in the males. Importantly, sex-specific expression of the Lon protein isoforms was also observed in mammalian tissues, suggesting a possible conservation of sex-specific Lon regulation. To assess Lon’s involvement in the male and female adaptive differences, males were transformed into ‘pseudo-females’ through over-expression of the female-specific Transformer (TraF) splicing factor. Pseudo-females recapitulated the female-specific Lon protein isoforms and H2O2 adaptation. Our findings suggest the use of D. melanogaster as a model for sex-specific stress adaptation regulated by the Lon protease, with potential implications for understanding sexual-dimorphism in disease.

Second-generation ethanol from sugarcane and sweet sorghum bagasses using the yeast Dekkera bruxellensis

In previous work we showed that the yeast Dekkera bruxellensis (strain GDB 248) is capable of assimilating cellobiose and converting this sugar to ethanol, a characteristic that may help in reducing the cost of biomass hydrolysis with commercial enzyme. In the present work we tested the efficiency of ethanol production by this yeast from bagasse of sugarcane (SCB) and sweet sorghum (SSB) after alkaline H2O2 pretreatment and enzymatic hydrolysis treatment. SSB contained less lignin and ashes and more waxes than SCB, resulting in more efficient pretreatment and enzyme hydrolysis, as evidenced by chemical and physical analysis. Glucose and cellobiose were released from cellulose, as well as xylose from the remaining hemicellulose. The hexoses were completely consumed with final yields of 0.42 (±0.04) g/g for SCB and 0.44 (±0.03) g/g for SSB. Acetate was not produced, which indicated that the fermentations were carried out under anaerobic condition. This yeast was capable of metabolising cellobiose for ethanol production, which therefore proves to be a promising industrial microorganism for the production of second-generation ethanol.

Optimization of Microwave-Hydrogen Peroxide Pretreatment of Cellulose

A hydrogen peroxide (H2O2) solution was adapted for microwave pretreatment of microcrystalline cellulose, which can be further used for heavy metal adsorption. The H2O2 concentration, temperature, and retention time were the key factors affecting the microwave/hydrogen peroxide pretreatment process. A Box-Benhken design (BBD) with response surface methodology (RSM) was employed to design and optimize the microwave-hydrogen peroxide pretreatment process (H2O2 pretreatment) of cellulose. After the H2O2 pretreatment, the crystallinity of cellulose decreased by 20% and the degree of polymerization (DP) decreased by up to 30%. The optimal conditions obtained by BBD were a H2O2 concentration of 8.37%, a temperature of 90 °C, and a retention time 5.33 min. Under these conditions, a minimum DP of 91.74 was achieved. The results indicated that all three of the factors notably affected the reduction of cellulose polymerization degree and pronounced interactions existed among the response variables. The predictive model developed was able to optimize the pretreatment process for the reduction of cellulose polymerization degree, which could improve the cellulose modification reactivity.

THE EFFECTS OF OXIDATIVE STRESS ON PHENOLIC COMPOSITION AND ANTIOXIDANT METABOLISM IN CALLUS CULTURE OF COMMON DAISY.

Background:Exogenous pretreatment of oxidative stress on callus cultures of Bellis perennis L. (common daisy) induced catalase (CAT), superoxide dismutase (SOD), total phenolic, total flavonoid, total protein and selected commercial phenolic compounds production and accumulation.Materials and Methods:The callus culture obtained from B. perennis pedicel explants was incubated on Murashige and Skoog medium (MS) containing 10 mM H2O2 or 0 mM H2O2 (for control group) for 10 hours. Twenty phenolic compounds (apigenin, caffeic acid, p-coumaric acid, gallic acid, genistein, kaempferol, luteolin, myricetin, procyanidin-C1, quercetin, rutin hydrate, vanillic acid, ferulic acid, salicylic acid, sinapic acid, chlorogenic acid, hesperedin, naringenin, rosmarinic acid and isorhamnetin) were detected by LC-ESI-MS/MS analysis in methanolic extracts of 10 mM H2O2 and control treatments.Results:A predominant phenolic compound was chlorogenic acid followed by rutin hydrate, caffeic acid, luteoline, isorhamnetin, quercetin, myricetin, apigenin, p-coumaric acid and kaempferol. No gallic acid, genistein, procyanidin-C1, vanillic acid, sinapic acid, hesperidin and naringenin were detected in H2O2 treatment and control groups of B. perennis. The total phenolic contents estimated were in the order of H2O2 treatment (285.36 μg/g dw) and control (220.79 μg/g dw) groups. The biosynthesis and accumulation of kaempferol, myricetin, quercetin and isorhamnetin were only determined in H2O2 treatment callus materials. The H2O2 pretreatment clearly showed in a raise in enzymatic and non-enzymatic antioxidant activities. Finally, a significant positive correlation between phenolic accumulation and comprehensive activities of CAT, SOD, total phenolic, total flavonoid and proline was accessible.Conclusion:The present results suggest that using H2O2 as an elicitor or a stimulant plays a significant enhancement role in special phenolic molecules biosynthesis and activation of antioxidant metabolism on callus cultures of B. perennis.

Improving yield and composition of protein concentrates from green tea residue in an agri-food supply chain: Effect of pre-treatment

Rather than improving crop-production yield, developing biorefinery technology for unused biomass from the agri-food supply chain may be the crucial factor to reach sustainable global food security. A successful example of food-driven biorefinery is the extraction of protein from green tea residues, however, alkali usage is high and the resulting low protein quality limits its application. The research objective was to investigate the influence of pre-treatments with ethanol, Viscozyme® L and/or H2O2 on the subsequent alkaline protein extraction, and on their possible products for food applications. Polyphenols and/or pigments can be obtained by ethanol pre-treatment. Galacturonic acid and glucose can be obtained using Viscozyme® L. Pre-treatments using ethanol or Viscozyme® L individually reduced alkali consumption by 25% and improved protein extraction yield and purity. Their combination has the best effect. Additionally, pre-treatment using 50% ethanol reduced browning by 59% while pre-treatment using Viscozyme® L increased contents of arginine, threonine, and serine in the final alkaline protein extract. H2O2 pre-treatment had a negative effect on the alkaline protein extraction. These pre-treatments and protein extraction can be added to the existing process.

Hydrogen peroxide affects plant growth promoting effects of Azospirillum

This study aimed to investigate if pretreatment seed with H2O2 affects promoting effect of Azospirillum on plant. The experiment was a factorial combination of two main factors, Azospirillum and hydrogen peroxide (0, 25, 50, and 80%), carried out under field conditions. Soaking seed in various concentrations of H2O2 solution resulted in enhanced stomata density and increased length and histological components of leaf. These changes in histological components were found to be positive since plants of H2O2-soaked seeds (H2O2 pretreatment) had higher fresh and dry weights, seed number per spike, and higher grain yield. Azospiriilum enhanced number of grain spikes-1 and total grain yield by 3% and 7%, respectively. Soaking seeds in 25% H2O2 solution enhanced the promoting effect of Azospirillum on increased vessels area and diameter. Soaking seeds in 50% H2O2 solution resulted in enhanced stimulating effect of Azospirillum on enhanced areas of vascular bundle and upper epidermis. The promoting effect of Azospirillum on the area of lower epidermis was largest when seed was pretreated with 80% H2O2. All three concentrations of H2O2 used had the same effect on Azospirillum–inoculated plant in terms of leaf area and chlorophyll a. Soaking seed in 80% H2O2 solution and then inoculated with Azospirillum resulted in the highest grain yields.

Increased drought tolerance in maize plants induced by H2O2 is closely related to an enhanced enzymatic antioxidant system and higher soluble protein and organic solutes contents

Drought stress is one of the most important agricultural problems limiting development and growth in plants. Therefore, mechanisms to alleviate drought stress have been one of the major limiting factors in production. H2O2 pretreatment has emerged as a method to induce stress acclimation in plants. In this study, the effects of H2O2 leaf pretreatment on plant growth, antioxidative enzymes, soluble protein, and organic solute content in maize plants under conditions of drought stress were analyzed. Results demonstrated that drought stress reduced shoot and root mass compared with the control, and H2O2 leaf spraying significantly improved the growth of drought-stressed plants. In general, in drought-stressed plants, CAT, APX, GPX, and SOD activities in roots and leaves were increased by H2O2 leaf spraying relative to water spraying. GPX was the main H2O2-scavenging enzyme in leaves and roots, and CAT activity was not detected in the leaves of maize plants. Increased organic solute contents (proteins, carbohydrates, soluble proline, and amino acids) were found in the leaves and mainly in the roots of H2O2-stressed plants relative to water-stressed plants. In conclusion, it was found that H2O2 leaf spraying pretreatment reduced the deleterious effects of drought stress on maize plant growth. This treatment proved to be a beneficial health strategy in plants. This effect could be attributed to the ability of H2O2 to induce antioxidant defense system activity, particularly GPX, and to increase organic solute (protein, carbohydrate, proline, and free amino acid) content in roots and leaves.

Role of Hydrogen Peroxide Preoxidizing on CO2 Adsorption of Nitrogen-Doped Carbons Produced from Coconut Shell

In this work, the coconut shell was preoxidized by hydrogen peroxide, before it was treated by the ammoxidation process and potassium hydroxide activation to synthesize nitrogen-doped porous carbons. The resulting sorbents exhibit significantly higher nitrogen content and narrow microporosity than the control sample without H2O2 pretreatment. Consequently, these sorbents are found to demonstrate high carbon dioxide uptake at 1 bar, such as 4.47 mmol g–1 at 25 °C and 6.79 mmol g–1 at 0 °C. In addition, these sorbents possess high CO2/N2 selectivity, stable reusability, high initial heat of CO2 adsorption, and high dynamic CO2 capture capacity under simulated flue gas conditions. These superior CO2 adsorption properties make them highly competitive among all the carbonaceous adsorbents for CO2 capture.

A New Method to Visualize the Intact Subretina From Retinal Pigment Epithelium to Retinal Tissue in Whole Mount of Pigmented Mouse Eyes.

PurposeThe subretinal layer between apical retinal pigment epithelium (RPE) and the apices of the photoreceptor outer segments is important to aging and degenerative pathogenesis, but current protocols do not provide intact horizontal images of this retinal space. Thus, an RPE/retina whole mount staining protocol was developed to observe integral subretinal regions.MethodsRPE/retina whole mounts were stained instead of separated retina or RPE whole mounts. Hydrogen peroxide (H2O2) treatment was applied in different conditions of concentration, time, and temperature for the bleaching of RPE and choroidal melanocyte pigmentation in the pigmented RPE/retina whole mounts before antibody staining.ResultsAn RPE/retina whole mount staining protocol provided better morphology of the photoreceptor outer segment than current retina whole mount. For the pigmented eyes, 10% H2O2 pretreatment effectively bleached melanin at 55°C less than 2 hours, or at 4°C within 7 days, without significant effect on immunolabeling efficacy of most antibodies tested. Actually, 55°C bleaching improved immunolabeling intensities compared to the nonbleaching control. This melanin bleaching RPE/retina protocol was applied further to observe macrophage/microglia extending from the sclera to outer plexiform layer in the CX3CR1+/GFP retina.ConclusionsThe pigment bleaching RPE/retina whole mount allowed integral horizontal imaging between choroid to photoreceptor layers, which could not be accomplished with existing methods of separated retina or RPE whole mount. Under these procedures, antigenicity of most antibodies also was well preserved.Translational RelevanceThis efficient protocol provides a tool to observe an integral view of subretinal structures including macrophage/microglia and transplanted cells, and further allows study of the interrelationship between the choroid and photoreceptor in models of aging, disease, and retinal degeneration.

A Comparative Study on the Utilization of Corn Pericarp and Peanut Hull in the Production of Ethanol and the Impact on Food Economics

Corn pericarp and peanut hull (lignocellulosic materials) which are food industry by-products were used as substrates in this study. Alkaline hydrogen peroxide (H2O2) pretreatments at 0%, 2.5% and 5% were used for the removal of lignin. Simultaneous Saccharification and Fermentation (SSF) and Separate Hydrolysis and Fermentation (SHF) were conducted using Aspergillus niger (strain 201201) and Saccharomyces cerevisiae (strain 26603). Aspergillus niger was added on day 1 to all samples with inoculation treatments of S. cerevisiae at one-day intervals (A = Day 1, B = Day 2, C = Day 3 and D = Day 4). Pretreatment with 2.5% H2O2 was more beneficial in the removal of lignin for both substrates. Corn pericarp yielded an ethanol concentration of 22.2 g/L in C and 21.78 g/L in D of 2.5% H2O2 pretreatment. Peanut hull with 2.5% H2O2 pretreatment in D yielded a higher concentration at 10.38 g/L compared to other inoculation treatments. The highest ethanol yielded on a percentage basis for corn pericarp was 45.04% in C of 2.5% H2O2 pretreatment and 24.6% in D of 2.5% H2O2 pretreatment for peanut hull.

H2O2 Pretreatment Modulates Growth and the Antioxidant Defense System of Drought-stressed Zoysiagrass and Kentucky Bluegrass

This study investigated the effect of exogenous hydrogen peroxide (H₂O₂) on the antioxidant responses and growth of warm-season turfgrass (Zoysia japonica Steud.) and cool-season turfgrass (Poa pratensis L.) subjected to drought stress. Compared with control plants that were not pretreated with H₂O₂, plants pretreated with H₂O₂ had significantly greater fresh and dry weights of shoots and roots, and increased water content. H₂O₂ pretreatments before drought stress significantly decreased the concentrations of malondialdehyde and H₂O₂. DPPH radical scavenging and glutathione activities were significantly increased. The responsive activities of the antioxidant enzymes superoxide dismutase, ascorbate peroxidase, catalase, and peroxidase were also significantly enhanced. Our results suggest that exogenous H₂O₂ could improve the growth of warm-season and cool-season turfgrass under drought stress by increasing the activity of their antioxidant enzymes, while decreasing lipid peroxidation.

Combined free nitrous acid and hydrogen peroxide pre-treatment of waste activated sludge enhances methane production via organic molecule breakdown.

This study presents a novel pre-treatment strategy using combined free nitrous acid (FNA i.e. HNO2) and hydrogen peroxide (H2O2) to enhance methane production from WAS, with the mechanisms investigated bio-molecularly. WAS from a full-scale plant was treated with FNA alone (1.54 mg N/L), H2O2 alone (10–80 mg/g TS), and their combinations followed by biochemical methane potential tests. Combined FNA and H2O2 pre-treatment substantially enhanced methane potential of WAS by 59–83%, compared to 13–23% and 56% with H2O2 pre-treatment alone and FNA pre-treatment alone respectively. Model-based analysis indicated the increased methane potential was mainly associated with up to 163% increase in rapidly biodegradable fraction with combined pre-treatment. The molecular weight distribution and chemical structure analyses revealed the breakdown of soluble macromolecules with the combined pre-treatment caused by the deamination and oxidation of the typical functional groups in proteins, polysaccharides and phosphodiesters. These changes likely improved the biodegradability of WAS.