Nitric oxide fumigation stimulates flavonoid and phenolic accumulation and enhances antioxidant activity of mushroom

A comprehensive profiling of phenolic compounds and antioxidant activities of 24 varieties of red raspberry cultivated in Northeast China

Red raspberries, valued for their nutrients and bioactive compounds, have broad uses in processing and healthy products. However, limited comprehensive research focused on the comparison of phenolic compounds of red raspberry, especially species cultivated in Northeast China, has been reported. This study aimed to conduct a thorough investigation of 24 red raspberry varieties in Northeast China for the first time, evaluating their phenolic compounds and antioxidant capacities. The results showed that 'DNS1' had the highest total phenolic content (TPC), 'Willamette' had the highest total flavonoid content (TFC), and 'Boyne' had the highest total anthocyanin content (TAC). Phenolic compounds in red raspberries were predominantly found in esterified form, while glycosylated phenolics should not be overlooked. Chlorogenic acid, cryptochlorogenic acid, ellagic acid, and arbutin were the main phenolic compounds, and the distribution of their contents varied between varieties. The antioxidant activity in the red raspberry had a close association with the content of phenolic compounds. Principal component analysis (PCA) showed that phenolic compounds and antioxidant activities were higher in samples from 'DNS1', 'Boyne', 'Beijing10', 'DNS5', and 'Willamette' varieties. These varieties should be given priority in breeding programs that aim to boost the utility and bioactive profile of red raspberries. PRACTICAL APPLICATION: Red raspberry is becoming a desirable commercially grown fruit species and is viewed as a new functional food. In this context, this research offers strong support for confirming the quality of 24 varieties of red raspberry and plays a critical role in the food industry. It also indicates the potential sources of superior varieties of red raspberry, which are advantageous for growers and consumers in search of high-quality red raspberry varieties.

Role of phenylpropanoid pathway in genetic regulation and physiological adaptation in arsenic stressed rice genotypes

This study investigates the role of the phenylpropanoid pathway in arsenic (As) contaminated rice genotypes under natural conditions, exploring the intricate relationship between genetic regulation and physiological adaptation. Differential approaches adapted by rice genotypes to counteract As exposure are elucidated here through analysis of enzyme activities and related gene expression patterns, docking simulations, and nutrient dynamics. Enzymatic analysis from the phenylpropanoid pathway revealed significant variations across rice genotypes, with Mini mansoori exhibiting notably higher activity levels of key enzymes (PAL, C4H, 4CL, CHI, DFR and F3H) compared to Sampoorna and Pioneer. Additionally, the gene expression profiling unveiled differential responses, with Mini mansoori and Pioneer demonstrating higher expression of genes (OsPAL, OsCHS, OsCHI, OsF3H, OsF3'H, OsFLS, OsDFR, and OsLAR) associated with As resistance and tolerance, compared to Sampoorna. Enrichment analysis emphasized the involvement of cinnamic acid biosynthesis and related pathways. Molecular docking depicted certain proteins, such as Os4CL, OsFLS, OsDFR, and OsLAR susceptible to As binding, potentially affecting enzymatic activity. Ionomic analysis unveiled that Mini mansoori maintained higher levels of essential nutrients such as Na, Ca, P, Mn, Mg, and Zn in grains. However, this contrasted with Pioneer and Sampoorna, which experienced nutrient imbalance likely due to higher As accumulation. Chlorophyll fluorescence analysis depicted that Mini mansoori and Pioneer maintained better photosynthetic efficiency under As toxicity compared to Sampoorna. Moreover, network analysis highlights the critical role of Mg and Na interaction with essential phenolics and flavonoids, in combating the stress. Harnessing this understanding, targeted breeding effort could yield As-resistant rice varieties with enhanced nutrient and flavonoid contents, addressing both food safety and malnutrition in affected regions.

The Effect of Cold Plasma Treatment on the Storage Stability of Mushrooms (Agaricus bisporus)

Postharvest Agaricus bisporus is susceptible to browning, water loss, and microbial infection. In order to extend its shelf life, cold plasma technology was used to treat and evaluate A. bisporus. Firstly, according to the results of a single factor test and response surface analysis, the optimal conditions for cold plasma treatment were determined as a voltage of 95 kV, a frequency of 130 Hz, and a processing time of 10 min. Secondly, storage experiments were carried out using the optimized cold plasma treatment. The results showed that the cold plasma treatment in the packaging significantly reduced the total viable count in A. bisporus by approximately 16.5%, maintained a browning degree at 26.9% lower than that of the control group, and a hardness at 25.6% higher than that of the control group. In addition, the cold plasma treatment also helped to preserve the vitamin C and total protein content of A. bisporus. In conclusion, cold plasma treatment showed great potential in enhancing the postharvest quality of fresh A. bisporus.

Stimulating action of sodium nitroprusside and vinasse on salicin and direct regeneration in Salix Safsaf Forssk

The present study aimed to enhance salicin and direct regeneration in willow (Salix safsaf Forssk) using the sodium nitroprusside (SNP) regulation of nitric oxide (NO) and vinasse for its nutrition effect in culture medium. Internodes of Salix safsaf were cultured on Murashige and Skoog (MS) medium supplemented with benzyl adenine (BA) (0.25 mg L-1) and different concentrations of SNP (0, 5, 10, 15, and 20 mg L-1) or vinasse (0, 5, 10, and 20%) to examine shoot regeneration, antioxidant defense enzyme activity, total phenolic compounds, flavonoids, and salicine contents. The reported data revealed that application of SNP at 15 mg L-1 and vinasse at 10% induced a significant effect in vitro Salix safsaf shoot regeneration. To confirm that, nitric oxide is required for auxin-mediated activation of cell division in a dose-dependent manner. A concentration of 15 mg L-1 SNP promotes regeneration and salicin accumulation (3162.16 mg/100 g) during signaling action. On the other hand, the cross talk effect of nitric oxide and vinasse combination in Salix safsaf significantly induced a synergistic effect on direct propagation more than vinasse alone. SNP significantly stimulates salicylate accumulation in a dose-dependent manner, but the data on the association of vinasse and SNP on salicylate up-regulation showed a significant reduction in salicin accumulation when SNP was combined with 10% vinasse, which directly affected the signaling action of SNP as secondary product stimulators. Vinasse's phenolic compounds affect directly on the reduction activity of SNP to suppress its signaling action, or indirectly by inhibiting the sequence cascade of the SNP signaling transduction process to decrease the accumulation of salicin contents. Data confirmed that vinasse and SNP stimulated the antioxidant enzymes activity throw quenching the stimulated reactive oxygen species that produced via SNP. Results show that modified media with SNP administration at 15 mg L-1 and the combination of vinasse at 10% and SNP at 15 mg L-1 are recommended for modifying tissue culture media for induced direct regeneration and salicin accumulation in tissue culture applications, which will be very useful for commercial salicin overproduction as a biological active ingredient in willows.

RNA-Seq-Based Transcriptome Analysis of Nitric Oxide Scavenging Response in Neurospora crassa

While the biological role of naturally occurring nitric oxide (NO) in filamentous fungi has been uncovered, the underlying molecular regulatory networks remain unclear. In this study, we conducted an analysis of transcriptome profiles to investigate the initial stages of understanding these NO regulatory networks in Neurospora crassa, a well-established model filamentous fungus. Utilizing RNA sequencing, differential gene expression screening, and various functional analyses, our findings revealed that the removal of intracellular NO resulted in the differential transcription of 424 genes. Notably, the majority of these differentially expressed genes were functionally linked to processes associated with carbohydrate and amino acid metabolism. Furthermore, our analysis highlighted the prevalence of four specific protein domains (zinc finger C2H2, PLCYc, PLCXc, and SH3) in the encoded proteins of these differentially expressed genes. Through protein-protein interaction network analysis, we identified eight hub genes with substantial interaction connectivity, with mss-4 and gel-3 emerging as possibly major responsive genes during NO scavenging, particularly influencing vegetative growth. Additionally, our study unveiled that NO scavenging led to the inhibition of gene transcription related to a protein complex associated with ribosome biogenesis. Overall, our investigation suggests that endogenously produced NO in N. crassa likely governs the transcription of genes responsible for protein complexes involved in carbohydrate and amino acid metabolism, as well as ribosomal biogenesis, ultimately impacting the growth and development of hyphae.

Polyamines inhibit abscisic acid-induced stomatal closure by scavenging hydrogen peroxide

Stomatal closure is regulated by plant hormones and some small molecules to reduce water loss under stress conditions. Both abscisic acid (ABA) and polyamines alone induce stomatal closure; however, whether the physiological functions of ABA and polyamines are synergistic or antagonistic with respect to inducing stomatal closure is still unknown. Here, stomatal movement in response to ABA and/or polyamines was tested in Vicia faba and Arabidopsis thaliana, and the change in the signaling components under stomatal closure was analyzed. We found that both polyamines and ABA could induce stomatal closure through similar signaling components, including the synthesis of hydrogen peroxide (H₂ O₂ ) and nitric oxide (NO) and the accumulation of Ca²⁺ . However, polyamines partially inhibited ABA-induced stomatal closure both in epidermal peels and in planta by activating antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), to eliminate the ABA-induced increase in H₂ O₂ . These results strongly indicate that polyamines inhibit abscisic acid-induced stomatal closure, suggesting that polyamines could be used as potential plant growth regulators to increase photosynthesis under mild drought stress.

Comprehensive Review of Recent Advances in Chiral A-Ring Flavonoid Containing Compounds: Structure, Bioactivities, and Synthesis

Flavonoids are a group of natural polyphenolic substances that are abundant in vegetables, fruits, grains, and tea. Chiral A-ring-containing flavonoids are an important group of natural flavonoid derivatives applicable in a wide range of biological activities such as, cytotoxic, anti-inflammatory, anti-microbial, antioxidant, and enzyme inhibition. The desirable development of chiral A-ring-containing flavonoids by isolation, semi-synthesis or total synthesis in a short duration proves their great value in medicinal chemistry research. In this review, the research progress of chiral A-ring-containing flavonoids, including isolation and extraction, structural identification, pharmacological activities, and synthetic methods, is comprehensively and systematically summarized. Furthermore, we provide suggestions for future research on the synthesis and biomedical applications of flavonoids.

Nitric Oxide Made a Major Contribution to the Improvement of Quality in Button Mushrooms (Agaricus bisporus) by the Combined Treatment of Nitric Oxide with 1-MCP

Browning is one of the major effects of shelf-life responsible for the reduction in the commercial value of the button mushrooms (Agaricus bisporus). In this study, the individual and the combined effects of exogenous sodium nitroprusside (SNP, a nitric oxide donor) and 1-methylcyclopropene (1-MCP) on the quality of button mushrooms were evaluated. The results demonstrated that mushrooms treated with SNP+1-MCP promoted reactive oxygen species (ROS) metabolism thereby protecting cell membrane integrity, hindering polyphenol oxidase (PPO) binding to phenolic compounds, and downregulating the PPO activity. In addition, the SNP+1-MCP treatment effectively maintained quality (firmness, color, total phenol, and flavonoid) and mitigated oxidative damage by reducing ROS accumulation and malondialdehyde production through the stimulation of the antioxidant enzymes activities and the enhancement of ascorbic acid (AsA) and glutathione (GSH) contents. Moreover, the correlation analysis validated the above results. The SNP+1-MCP treatment was observed to be more prominent on maintaining quality than the individual effects of SNP followed by 1-MCP, suggesting that the combination of NO and 1-MCP had synergistic effects in retarding button mushrooms senescence, and NO signaling molecules might be predominant in the synergy.

Alleviation of postharvest chilling injury in sweet pepper using Salicylic acid foliar spraying incorporated with caraway oil coating under cold storage

The decrease in the postharvest quality of sweet peppers in terms of the physiological disorders resulting from cold storage (<7-10°C) results in the significant economic losses. The ability of pre-harvest foliar spraying of Salicylic acid (SA) (1.5 and 3 mM) and the postharvest caraway (Carum carvi) oil coating (0.3% and 0.6%) on chilling injury (CI) and the quality of stored sweet pepper at 4 ± 2°C for 60 d followed by an additional 2 d at 20°C were investigated. The antifungal activity of caraway oil (0.15%, 0.3%, and 0.6%) on Botrytis cinerea mycelia in in vitro showed that the maximum percentage of inhibition was equal to 95% in the medium with 0.6% of this oil. The CI of sweet pepper was significantly reduced by increasing SA, and caraway oil concentrations compared to the control, especially the lowest CI (14.36%), were obtained at 3 mM SA and 0.6% caraway oil treatment. The results showed a significant delay in the changes of weight loss (79.43%), firmness (30%), pH (6%), total soluble solids (TSS) (17%), titratable acidity (TA) (32%), and color surface characteristics and capsaicin content (5%) compared to control fruits at 3 mM SA and 0.6% caraway oil concentrations. Results indicated that the decrease in CI was related to a decrease in electrolyte leakage, malondialdehyde (MDA) content, total phenolic production, decay incidence, and an increase in the activity of antioxidant enzymes, including catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD). Thus, the incorporation of SA (3 mM) and caraway oil (0.6%) to reduce the CI of stored sweet pepper at low temperature can be considered a practical solution to improve the quality and marketability of this product.

Transcriptomic and Non-Targeted Metabolomic Analyses Reveal the Flavonoid Biosynthesis Pathway in Auricularia cornea

Flavonoids, which are abundant in plants, are recognized for their antioxidant and anticancer roles in clinical applications. However, little is known about the molecular basis of flavonoid biosynthesis in fungi. In this study, we found that inclusion of leachate of Korshinsk peashrub (Caragana korshinskii) in the fermentation medium increased the total flavonoid content of the edible fungus Auricularia cornea by 23.6% relative to that grown in a control medium. Combined transcriptomic and non-targeted metabolomic analysis of the flavonoid biosynthesis pathway in A. cornea illustrated that there are important metabolites in the phenylpropanoid, coumarin and isoflavonoid biosynthesis pathways. In addition, we found that certain homologous genes encode phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO) and chalcone isomerase (CHI) in these biosynthesis pathways. These results, in this study, provide a new line for studying the regulation of flavonoid production in edible fungi.

Synergy of Nitric Oxide and 1-Methylcyclopropene Treatment in Prolong Ripening and Senescence of Peach Fruit

Peach is a putrescible fruit thus drastically restricting its postharvest storage life. In recent years, the application of 1-methylcyclopropene (1-MCP) and nitric oxide (NO) in postharvest fruit quality control has received considerable attention and investigative efforts due to the advantages of using relatively low concentrations and short-time treatment duration. In the present study, the effects of various 1-MCP and NO treatments on peach fruit (Prunus persica L. cv. Xiahui-8) stored at 25 °C were evaluated and compared. Results indicated that the combination treatment with both chemical agents (MN) was most effective in postponing peach ripening and preserving fruit quality, followed by 1-MCP and NO treatment alone. We also demonstrated that NO could delay fruit senescence mainly by stimulating antioxidant enzymes, while 1-MCP overly outperformed NO in the treatment of ‘Xiahui-8′ peach in slowing down respiration rate, inhibiting ethylene production, maintaining high firmness and reducing ROS content. NO treatment showed a greater influence on phenolic compounds than 1-MCP especially anthocyanins, flavanones and flavones according to LC/MS analysis. The phenolic change in MN group were highly associated to NO treatment. Through this study we provide informative physiological, biochemical and molecular evidence for the beneficial effects of the combined 1-MCP and NO treatment on peach fruit based on a functional synergy between these two chemical agents.

A Possibility to Use Selected Crop Post-Extraction Wastes to Improve the Composition of Cultivated Mushroom Pleurotus citrinopileatus

A cultivated mushroom species, Pleurotus citrinopileatus, is becoming increasingly popular thanks to its attractive colour and medicinal properties. In this study, P. citrinopileatus was grown in a cultivation medium enriched with wheat bran (WB), thymus post-extraction waste (TPEW) and pumpkin post-extraction waste (PPEW) products. The study showed that the post-extraction wastes are a crucial factor determining the accumulation of minerals, the content/profile of low-molecular-weight organic acids (LMWOAs) and phenolic compounds in fruit bodies, thereby increasing their nutritional value. The use of the waste materials significantly increased LMWOAs contents. The sum of LMWOAs under all cultivation mediums increased, especially quinic, malic and citric acids under the 20% PPEW, 25 and 50% TPEW addition. Total phenolic content, phenolic content, as well as the composition and scavenging effect on DPPH radicals, were strongly dependent on the used substrate. The control variant was poor in phenolic compounds, while the supplementation increased the contents and diversity of these metabolites. In the control, only four phenolic compounds were quantified (chlorogenic, gallic, syringic and vanillic acids), while in the supplemented substrates up to 14 different phenolic compounds (caffeic, chlorogenic, p-coumaric, 2,5-dihydroxybenzoic acid, ferulic, gallic, protocatechuic, salicylic, sinapic, syringic, trans-cinnamic and vanillic acids, catechin and rutin).

The importance of Cu × Pb interactions to Lentinula edodes yield, major/trace elements accumulation and antioxidants

Due to the use of various substrates in the production of edible mushrooms which may contain metals, including Cu and Pb, it is important to understand the influence of mutual interactions between them in the process of their accumulation in fruit bodies. For this reason, the effects of Cu, Pb, and Cu × Pb on yield, accumulation of five major elements (Ca, K, Mg, Na and P), trace elements (Cu, Pb and Fe) and some bioactive compounds in Lentinula edodes fruit bodies were studied. Both the metals were added in doses of 0.1 and 0.5 mM (Cu0.1, Cu0.5, Pb0.1, Pb0.5 and their combinations). The addition of the metals resulted in a reduction in size, amount and finally yield of fruit bodies. Depending on the presence of Cu and or Pb and their concentration in the substrate, both antagonism and synergism may occur. The influence on the accumulation of other determining elements was also recorded. Among phenolic compounds, phenolic acids and flavonoids were detected. 2,5-Dihydroxybenzoic acid dominated in fruit bodies in the control variant, Pb0.1, Pb0.5 and all experimental variants enriched with Cu + Pb, while gallic acid was the major phenolic after Cu0.1 and Cu0.5 addition. Only protocatechuic acid content increased in all combinations. A significant decrease of all aliphatic acid contents in comparison to the control variant was observed in the Cu0.1 and Pb0.1 variants. Significant stimulation of aliphatic acid synthesis was recorded in Cu0.5 and Pb0.5 variants and in the mixture of both the metals. The additions pointed to the possible role of the determined molecules in detoxification mechanisms.

Alternative oxidase gene induced by nitric oxide is involved in the regulation of ROS and enhances the resistance of Pleurotus ostreatus to heat stress

Background

In China, during the cultivation process of Pleurotus ostreatus, the yield and quality of fruiting bodies are easily affected by high temperatures in summer. Nitric oxide (NO) plays an important regulatory role in the response to abiotic stress, and previous studies have found that NO can induce alternative oxidase (aox) experssion in response to heat stress (HS) by regulating aconitase. However, the regulatory pathway of NO is complex, and the function and regulation of the aox gene in the response to HS remain unclear.

Results

In this study, we found that NO affected nicotinamide adenine dinucleotide (NADH) and adenosine triphosphate (ATP) levels, reduced hydrogen peroxide (H₂O₂) and superoxide anion (O₂⁻) contents, and slowed O₂⁻ production. Further RNA-Seq results showed that NO regulated the oxidation-reduction process and oxidoreductase activity, affected the cellular respiration pathway and activated aox gene expression. The function of aox was determined by constructing overexpression (OE) and RNA interference (RNAi) strains. The results showed that the OE-aox strains exhibited obviously improved growth recovery after exposure to HS. During exposure to HS, the OE-aox strains exhibited reduced levels of NADH, the product of the tricarboxylic acid (TCA) cycle, and decreased synthesis of ATP, which reduced the production and accumulation of reactive oxygen species (ROS), whereas the RNAi-aox strains exhibited the opposite result. In addition, aox mediated the expression of antioxidant enzyme genes in the mycelia of P. ostreatus under HS through the retrograde signaling pathway.

Conclusions

This study shows that the expression of the aox gene in P. ostreatus mycelia can be induced by NO under HS, that it regulates the TCA cycle and cell respiration to reduce the production of ROS, and that it can mediate the retrograde signaling pathway involved in the mycelial response to HS.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12934-021-01626-y.

Blue and UV-B light synergistically induce anthocyanin accumulation by co-activating nitrate reductase gene expression in Anthocyanin fruit (Aft) tomato

The tomato accession LA1996, which carries a dominant allele of anthocyanin fruit (Aft) locus, accumulates anthocyanins in the epidermis of fruits when exposed to sunlight. The involvement of blue, UV-A, UV-B and a combination of these wavelengths on anthocyanin accumulation and the molecular mechanism of their regulation was investigated in LA1996. The most effective treatment for inducing anthocyanin biosynthesis in Aft fruits was co-irradiation with blue and UV-B (blue + UV-B) light. Finding the correlated genes is an important approach towards understanding their molecular mechanisms. In the present study, the nitrate reductase (NR) gene SlNIA was isolated using RNA-seq profiling of Aft fruits given different light treatments. The functions of NR-mediated anthocyanin induction by blue + UV-B were confirmed using a series of chemical treatments, followed by assessment of NR activity and nitric oxide (NO) detection. The expression of NR was highly induced by blue + UV-B, and this specificity was also confirmed with the enzyme activity of NR and the NO concentration. The NR inhibitors, which reduce NO generation, the expression levels of anthocyanin related genes and decreased anthocyanin accumulation in LA1996. Our results suggest that NR plays a key role in blue + UV-B-mediated anthocyanin accumulation in LA1996 fruits.

Nitric oxide donor sodium nitroprusside-induced transcriptional changes and hypocrellin biosynthesis of Shiraia sp. S9

Background

Nitric oxide (NO) is a ubiquitous signaling mediator in various physiological processes. However, there are less reports concerning the effects of NO on fungal secondary metabolites. Hypocrellins are effective anticancer photodynamic therapy (PDT) agents from fungal perylenequinone pigments of Shiraia. NO donor sodium nitroprusside (SNP) was used as a chemical elicitor to promote hypocrellin biosynthesis in Shiraia mycelium cultures.

Results

SNP application at 0.01–0.20 mM was found to stimulate significantly fungal production of perylenequinones including hypocrellin A (HA) and elsinochrome A (EA). SNP application could not only enhance HA content by 178.96% in mycelia, but also stimulate its efflux to the medium. After 4 days of SNP application at 0.02 mM, the highest total production (110.34 mg/L) of HA was achieved without any growth suppression. SNP released NO in mycelia and acted as a pro-oxidant, thereby up-regulating the gene expression and activity of reactive oxygen species (ROS) generating NADPH oxidase (NOX) and antioxidant enzymes, leading to the increased levels of superoxide anion (O₂⁻) and hydrogen peroxide (H₂O₂). Gene ontology (GO) analysis revealed that SNP treatment could up-regulate biosynthetic genes for hypocrellins and activate the transporter protein major facilitator superfamily (MFS) for the exudation. Moreover, SNP treatment increased the proportion of total unsaturated fatty acids in the hypha membranes and enhanced membrane permeability. Our results indicated both cellular biosynthesis of HA and its secretion could contribute to HA production induced by SNP.

Conclusions

The results of this study provide a valuable strategy for large-scale hypocrellin production and can facilitate further understanding and exploration of NO signaling in the biosynthesis of the important fungal metabolites.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12934-021-01581-8.

Molecular functions of nitric oxide and its potential applications in horticultural crops

Nitric oxide (NO) regulates plant growth, enhances nutrient uptake, and activates disease and stress tolerance mechanisms in most plants, making NO a potential tool for use in improving the yield and quality of horticultural crop species. Although the use of NO in horticulture is still in its infancy, research on NO in model plant species has provided an abundance of valuable information on horticultural crop species. Emerging evidence implies that the bioactivity of NO can occur through many potential mechanisms but occurs mainly through S-nitrosation, the covalent and reversible attachment of NO to cysteine thiol. In this context, NO signaling specifically affects crop development, immunity, and environmental interactions. Moreover, NO can act as a fumigant against a wide range of postharvest diseases and pests. However, for effective use of NO in horticulture, both understanding and exploring the biological significance and potential mechanisms of NO in horticultural crop species are critical. This review provides a picture of our current understanding of how NO is synthesized and transduced in plants, and particular attention is given to the significance of NO in breaking seed dormancy, balancing root growth and development, enhancing nutrient acquisition, mediating stress responses, and guaranteeing food safety for horticultural production.

Fungal chitin-glucan nanopapers with heavy metal adsorption properties for ultrafiltration of organic solvents and water

Membranes and filters are essential devices, both in the laboratory for separation of media, solvent recovery, organic solvent and water filtration purposes, and in industrial scale applications, such as the removal of industrial pollutants, e.g. heavy metal ions, from water. Due to their solvent stability, biologically sourced and renewable membrane or filter materials, such as cellulose or chitin, provide a low-cost, sustainable alternative to synthetic materials for organic solvent filtration and water treatment. Here, we investigated the potential of fungal chitin nanopapers derived from A. bisporus (common white-button mushrooms) as ultrafiltration membranes for organic solvents and aqueous solutions and hybrid chitin-cellulose microfibril papers as high permeance adsorptive filters. Fungal chitin constitutes a renewable, easily isolated, and abundant alternative to crustacean chitin. It can be fashioned into solvent stable nanopapers with pore sizes of 10-12 nm, as determined by molecular weight cut-off and rejection of gold nanoparticles, that exhibit high organic solvent permeance, making them a valuable material for organic solvent filtration applications. Addition of cellulose fibres to produce chitin-cellulose hybrid papers extended membrane functionality to water treatment applications, with considerable static and dynamic copper ion adsorption capacities and high permeances that outperformed other biologically derived membranes, while being simpler to produce, naturally porous, and not requiring crosslinking. The simple nanopaper production process coupled with the remarkable filtration properties of the papers for both organic solvent filtration and water treatment applications designates them an environmentally benign alternative to traditional membrane and filter materials.

Effects of nitric oxide treatment on flavour compounds and antioxidant enzyme activities of button mushroom (Agaricus bisporus) during storage

Button mushroom (Agaricus bisporus) is sold well for its unique flavour and nutritional benefits. However, the mushroom flavour deteriorates quickly during storage because of its delicate structure and high moisture. In this study, the effects of nitric oxide (NO) application on flavour compounds and antioxidant enzyme activities of stored button mushrooms were investigated. The button mushrooms were immersed in the NO donor sodium nitroprusside (15 μmol/L) for 3 min and then stored under the condition of 4 °C, 90% relative humidity for 12 days. Results showed that the treated mushrooms have reduced weight loss rate, uniform white colour, and higher firmness during storage. Compared to the control, the ketones, alcohols, esters, and aldehydes in the NO-treated button mushroom increased sharply at 3 days of storage and then showed a continuing decline trend, except ester compounds which reached the peak value at 6 days of storage. In addition, NO treatment increased the total phenolics and catalase activity and inhibited the polyphenol oxidase activity in the stored button mushroom. These results indicated that NO treatment is an alternative storage technology to enhance antioxidant capacity and maintain flavour and consumer acceptance of stored button mushroom.

The Effect of Mushroom Extracts on Human Platelet and Blood Coagulation: In vitro Screening of Eight Edible Species

Cardiovascular diseases remain the leading global cause of mortality indicating the need to identify all possible factors reducing primary and secondary risk. This study screened the in vitro antiplatelet and anticoagulant activities of hot water extracts of eight edible mushroom species (Agaricus bisporus, Auricularia auricularia-judae, Coprinuscomatus, Ganodermalucidum, Hericium erinaceus, Lentinulaedodes, Pleurotuseryngii, and Pleurotusostreatus) increasingly cultivated for human consumption, and compared them to those evoked by acetylsalicylic acid (ASA). The antioxidant capacity and concentration of polysaccharides, phenolic compounds, organic acids, ergosterol, macro elements, and trace elements were also characterized. The most promising antiplatelet effect was exhibited by A. auricularia-judae and P. eryngii extracts as demonstrated by the highest rate of inhibition of adenosine-5′-diphosphate (ADP)-induced and arachidonic acid (AA)-induced aggregation. The response to both extracts exceeded the one evoked by 140 µmol/L of ASA in the ADP test and was comparable to it in the case of the AA test. Such a dual effect was also observed for G. lucidum extract, even though it was proven to be cytotoxic in platelets and leukocytes. The extract of P. ostreatus revealed an additive effect on AA-induced platelet aggregation. None of the mushroom extracts altered the monitored coagulation parameters (prothrombin time, prothrombin ratio, and International Normalized Ratio). The effect of mushroom extracts on platelet function was positively related to their antioxidative properties and concentration of polysaccharides and ergosterol, and inversely related to zinc concentration. The study suggests that selected mushrooms may exert favorable antiplatelet effects, highlighting the need for further experimental and clinical research in this regard.

The effect of drying temperature on bioactive compounds and antioxidant activity of Leccinum scabrum (Bull.) Gray and Hericium erinaceus (Bull.) Pers

In the study the effect of drying temperature on phenolic and organic acid content, total phenolic content, ergosterol content, antioxidant activity and content of 40 elements in fruiting bodies of Leccinum scabrum and Hericium erinaceus was estimated. The analysis was performed for fresh fruiting bodies and those dried at 20, 40 and 70 °C. Drying resulted in changes in the profile of phenolic and organic acids. Drying generally resulted in losses of the content of total phenolics, ergosterol and antioxidant activity in both species. However, a reduction and an increase of phenolic acids and organic acids were observed. The greatest reduction of the compounds was generally observed at 70 °C. The greatest losses concerned organic acids (some single components and total) (even more than 90% of some compounds). The inhibition of free radicals decreased in the following order: fresh samples > air-dried samples > samples dried at 40 °C > samples dried at 70 °C. The drying temperature affected only selected element contents in fruiting bodies.

Chitosan nanoparticles-loaded Citrus aurantium essential oil: a novel delivery system for preserving the postharvest quality of Agaricus bisporus

BACKGROUND

One of the main problems in the button mushroom industry is the rapid deterioration of fruit bodies after harvest. Today, nanotechnology has become a more reliable technique to improve the quality of products in food packaging. In the present study, the effectiveness of chitosan nanoparticles containing Citrus aurantium essential oil on postharvest quality of white button mushroom was examined and compared to essential oil fumigation and control treatments.

RESULTS

Based on high-resolution transmission electron microscopy and dynamic light scattering, nanoparticles exhibited a spherical shape of 20-60 nm diameter. The results revealed that the application of chitosan nanoparticles loaded with C. aurantium oil significantly decelerated the rate of color change, weight loss and firmness compared to fumigation with essential oil and control treatments. Treatment of fruit bodies with chitosan nanoparticles loaded with C. aurantium oil promoted the accumulation of phenolic compounds and ascorbic acid, and resulted in increases in catalase and superoxide dismutase and a decrease in polyphenol oxidase activities, as the highest antioxidant capacity was observed after 15 days of cold storage.

CONCLUSION

This present research demonstrates that gradual release of C. aurantium essential oil from chitosan nanoparticles could be an effective and practical method for extending the shelf life of white button mushroom up to 15 days without significant decrease in antioxidant capacity. © 2018 Society of Chemical Industry.

Exogenous nitric oxide induces disease resistance against Monilinia fructicola through activating the phenylpropanoid pathway in peach fruit

BACKGROUND

Nitric oxide (NO) is a multifunctional signaling molecule involved in plant-induced resistance to disease. The present study aimed to investigate the relationship between disease resistance induced by NO and the phenylpropanoid pathway in peach fruit. The present study investigated the effect of NO on the main enzymes and metabolites of the phenylpropanoid pathway of harvested peach, which are probably related to disease resistance against Monilinia fructicola.

RESULTS

The results showed that treatment with 15 µmol L^-1 NO significantly (P < 0.05) enhanced the activities of phenylalanine ammonia-lyase, cinnamate-4-hydroxylase, 4-coumaroyl-CoA ligase, chalcone synthase and chalcone isomerase and the expression of their genes. Furthermore, NO treatment significantly (P < 0.05) increased the contents of total phenolics, flavonoids and lignin over the entire storage period and maintained higher total anthocyanin, phenolic acid and anthocyanin contents during the earlier storage period.

CONCLUSION

These results suggest that NO treatment could activate the phenylpropanoid pathway to enhance the activity of related enzymes and the contents of phenylpropanoid metabolites in peach to improve disease resistance and prevent pathogenic invasion. © 2016 Society of Chemical Industry.

Metabolism of Flavonoids in Novel Banana Germplasm during Fruit Development

Banana is a commercially important fruit, but its flavonoid composition and characteristics has not been well studied in detail. In the present study, the metabolism of flavonoids was investigated in banana pulp during the entire developmental period of fruit. 'Xiangfen 1,' a novel flavonoid-rich banana germplasm, was studied with 'Brazil' serving as a control. In both varieties, flavonoids were found to exist mainly in free soluble form and quercetin was the predominant flavonoid. The most abundant free soluble flavonoid was cyanidin-3-O-glucoside chloride, and quercetin was the major conjugated soluble and bound flavonoid. Higher content of soluble flavonoids was associated with stronger antioxidant activity compared with the bound flavonoids. Strong correlation was observed between antioxidant activity and cyanidin-3-O-glucoside chloride content, suggesting that cyanidin-3-O-glucoside chloride is one of the major antioxidants in banana. In addition, compared with 'Brazil,' 'Xiangfen 1' fruit exhibited higher antioxidant activity and had more total flavonoids. These results indicate that soluble flavonoids play a key role in the antioxidant activity of banana, and 'Xiangfen 1' banana can be a rich source of natural antioxidants in human diets.

S-nitroso-proteome in poplar leaves in response to acute ozone stress

Protein S-nitrosylation, the covalent binding of nitric oxide (NO) to protein cysteine residues, is one of the main mechanisms of NO signaling in plant and animal cells. Using a combination of the biotin switch assay and label-free LC-MS/MS analysis, we revealed the S-nitroso-proteome of the woody model plant Populus x canescens. Under normal conditions, constitutively S-nitrosylated proteins in poplar leaves and calli comprise all aspects of primary and secondary metabolism. Acute ozone fumigation was applied to elicit ROS-mediated changes of the S-nitroso-proteome. This treatment changed the total nitrite and nitrosothiol contents of poplar leaves and affected the homeostasis of 32 S-nitrosylated proteins. Multivariate data analysis revealed that ozone exposure negatively affected the S-nitrosylation status of leaf proteins: 23 proteins were de-nitrosylated and 9 proteins had increased S-nitrosylation content compared to the control. Phenylalanine ammonia-lyase 2 (log2[ozone/control] = −3.6) and caffeic acid O-methyltransferase (−3.4), key enzymes catalyzing important steps in the phenylpropanoid and subsequent lignin biosynthetic pathways, respectively, were de-nitrosylated upon ozone stress. Measuring the in vivo and in vitro phenylalanine ammonia-lyase activity indicated that the increase of the phenylalanine ammonia-lyase activity in response to acute ozone is partly regulated by de-nitrosylation, which might favor a higher metabolic flux through the phenylpropanoid pathway within minutes after ozone exposure.

Antioxidant properties of mushroom mycelia obtained by batch cultivation and tocopherol content affected by extraction procedures

The determination of the antioxidant potential of lyophilized mushroom mycelia from 5 strains of the species Pleurotus ostreatus and Coprinus comatus (obtained by submerged cultivation in batch system) was analyzed as ethanolic extracts by evaluating ABTS and the hydroxyl scavenging activity, FRAP method, the chelating capacity, the inhibition of human erythrocyte hemolysis, and the inhibition of xanthine oxidase activity. The main compounds present in all extracts were determined by HPLC chromatography. Overall, results demonstrated that the biologically active substances content is modulated by the extraction method used. The most beneficial extract, characterized by determining the EC₅₀ value, was that of C. comatus M8102, followed by P. ostreatus PQMZ91109. Significant amount of α-tocopherol (179.51 ± 1.51 mg/100 g extract) was determined as well as flavones such as rutin and apigenin. In the P. ostreatus PQMZ91109 extract, 4.8 ± 0.05 mg/100 g extract of tocopherol acetate known to play a significant role as an antioxidant in skin protection against oxidative stress generated by UV rays was determined. The various correlations (r² = 0.7665–0.9426 for tocopherol content) assessed and the composition of extracts in fluidized bed from the mycelia of the tested species depicted a significant pharmacological potential as well as the possibility of usage in the development of new functional products.

Effect of nitric oxide on antioxidative response and proline metabolism in banana during cold storage

The effect of exogenous nitric oxide (NO) on chilling injury to banana fruit was investigated. Banana fruit was treated with NO donor sodium nitroprusside of 0.05 mM at 20 °C for 10 min and then stored at 7 °C for up to 20 days. Banana fruit treated with NO sustained a lower chilling injury index and higher firmness and kept lower electrolyte leakage and malondialdehyde content than the control. Further investigation showed that NO treatment enhanced activities of guaiacol peroxidase, ascorbate peroxidase, and glutathione reductase compared to the control. It also maintained higher ascorbic acid, reduced glutathione content, and total antioxidant capacity but reduced hydrogen peroxide and superoxide anion to lower levels compared to control fruit during storage. NO treatment significantly enhanced the accumulation of total phenolics and proline, which resulted from the increased activities of phenylalanine ammonia-lyase and Δ¹-pyrroline-5-carboxylate synthetase and decreased proline dehydrogenase activity. We proposed that the enhanced chilling tolerance induced by NO treatment may result from the reduction of oxidative stress and proline accumulation.

Protective effects of extracts from Fructus rhodomyrti against oxidative DNA damage in vitro and in vivo

OBJECTIVE

To evaluate the potential protective effects of extracts from Fructus rhodomyrti (FR) against oxidative DNA damage using a cellular system and the antioxidant ability on potassium bromate- (KBrO3-) mediated oxidative stress in rats.

METHODS

The effects of FR on DNA damage induced by hydrogen peroxide (H2O2) were evaluated by comet assay in primary spleen lymphocytes cultures. The effects of FR on the activities of SOD, CAT, and GPx and the levels of GSH, hydroperoxides, and 8-OHdG were determined in the plasma and tissues of rats treated with KBrO3.

RESULTS

FR was shown to effectively protect against DNA damage induced by H2O2  in vitro, and the maximum protective effect was observed when FR was diluted 20 times. Endogenous antioxidant status, namely, the activities of SOD, CAT, and GPx and the levels of GSH were significantly decreased in the plasma, the liver, and the kidney of the KBrO3-treated rats, while the pretreatment of FR prevented the decreases of these parameters. In addition, the pretreatment of FR was also able to prevent KBrO3-induced increases in the levels of hydroperoxides and 8-OHdG in the plasma, the liver, and the kidney in rats.

CONCLUSIONS

Our findings suggested that FR might act as a chemopreventive agent with antioxidant properties offering effective protection against oxidative DNA damage in a concentration-dependent manner in vitro and in vivo.