[Research progress on structures, activities, and biosynthesis of blazeispirol compounds from Agaricus blazei].

Agaricus blazei is a rare medicinal and edible fungus with a crispy taste and delicious flavor. Both fruiting body and mycelium are rich in polysaccharides, sterols, terpenoids, peptides, lipids, polyphenols, and other active ingredients, which have strong pharmacological activities such as anti-tumor, lipid-lowering, glucose-lowering, immunomodulation, optimization of intestinal flora, and anti-oxidation. Therefore, it is a kind of fungal resource with a great prospect of edible and medicinal development. Among the reported chemical components of A. blazei, blazeispirol is a series of sterol compounds unique to A. blazei, which has a spiral structure and is different from classical steroids. It is an important active ingredient found in the mycelium of A. blazei and has significant hepatoprotective activity. It can be used as a phylogenetic and chemotaxonomic marker of A. blazei strains and is considered an excellent lead compound for drug development. According to the skeleton structure characteristics, the 17 discovered blazeispirol compounds can be divided into two types: blazeispirane and problazeispirane. In order to further explore the resource of blazeispirol compounds of A. blazei, the discovery, isolation, structure, biological activity, and biosynthetic pathways of blazeispirol compounds of A. blazei were systematically reviewed. Besides, the metabolic regulation strategies related to the fermentation synthesis of blazeispirol A by A. blazei were discussed. This review could provide a reference for the efficient synthesis and development of blazeispirol compounds, the research and development of related drugs and functional foods, and the quality improvement of A. blazei and other medicinal and edible fungi resources and derivatives.

Transcriptome and Hormonal Analysis of Agaricus bisporus Basidiome Response to Hypomyces perniciosus Infection.

Agaricus bisporus (Lange) Imbach is the most widely cultivated mushroom in the world. A. bisporus wet bubble disease is one of the most severe diseases of white button mushrooms and is caused by the fungal pathogen Hypomyces perniciosus. The pathogen causes a drastic reduction in mushroom yield because of malformation and deterioration of the basidiomes. However, the mechanism of the button mushroom's malformation development after infection with H. perniciosus remains obscure. Therefore, to reveal the mechanism of A. bisporus malformation caused by H. perniciosus, the interaction between the pathogen and host was investigated in this study using histopathological, physiological, and transcriptomic analyses. Results showed that irrespective of the growth stages of A. bisporus basidiomes infected with H. perniciosus, the host's malformed basidiomes and enlarged mycelia and basidia indicated that the earlier the infection with H. perniciosus, the more the malformation of the basidiomes. Analyzing physiological and transcriptomic results in tandem, we concluded that H. perniciosus causes malformation development of A. bisporus mainly by affecting the metabolism level of phytohormones (N6-isopentenyladenosine, cis-zeatin, and N6-[delta 2-isopentenyl]-adenine) of the host's fruiting bodies rather than using toxins. Our findings revealed the mechanism of the button mushroom's malformation development after infection with H. perniciosus, providing a reference for developing realistic approaches to control mushroom diseases. Our results further clarified the interaction between A. bisporus and H. perniciosus and identified the candidate genes for A. bisporus wet bubble disease resistance breeding. Additionally, our work provides a valuable theoretical basis and technical support for studying the interaction between other pathogenic fungi and their fungal hosts.

Lignocellulose Degradation Efficiency of Agaricus bisporus Strains Grown on Wheat Straw-Based Compost.

The cultivation of Agaricus bisporus was investigated with two commercial strains, A15 and W192. Nitrogen and lignocellulose were analyzed in absolute amounts based on mass balance to accurately compare the degradation efficiency of the compost, and the correlation between the degradation efficiency and extracellular enzyme activity of the mycelium was analyzed. Lignocellulose utilization efficiency positively correlated with mushroom yield. For the same strain, the compost with high lignocellulose content resulted in high utilization efficiency, which increased the yield of A. bisporus. For the same compost, the lignocellulose utilization efficiency of A15 was higher than that of W192. The activities of manganese-dependent peroxidase and ß-glucosidase indicated that W192 may have a higher demand for lignin and cellulose. Therefore, a higher yield of W192 was obtained with high-lignocellulose compost. The metabolism of cellulose and hemicellulose in the mycelial growth stage seemed to be conducive to high mushroom yield.

Insights into the genomic evolution and the alkali tolerance mechanisms of Agaricus sinodeliciosus by comparative genomic and transcriptomic analyses.

Agaricus sinodeliciosus is a rare wild edible mushroom from northwest China, and grows naturally in mild saline-alkali soil, which is also unusual in mushrooms. A. sinodeliciosus represents a potential model organism for explaining saline-alkali tolerance mechanisms and revealing related physiological processes in mushrooms. Here, we provide a high-quality genome of A. sinodeliciosus. Comparative genomic analyses reveal A. sinodeliciosus has numerous changes to its genome organization after a solitary evolutionary history under saline-alkali environments, such as gene family contraction, retrotransposon expansion and rapid evolution of adaptative genes. Our saline and alkali tolerance tests show that mycelium growth and fruit body formation of this species are effected by mild alkalinity. Transcriptomic analyses reveal that genes involved in carbon and nitrogen utilization, cell stability and fruit body formation of A. sinodeliciosus could be activated under mildly alkaline conditions. In particular, the 'starch and sucrose metabolism', 'biosynthesis of amino acids' and 'phenylpropanoid biosynthesis' pathways are important for mildly alkaline tolerance of A. sinodeliciosus. Like plants and arbuscular mycorrhizal fungi, in the rot fungus A. sinodeliciosus, the biosynthesis of intracellular small molecules could be enhanced to counter osmotic and oxidative stresses caused by mild alkalinity, and the biosynthesis of monolignol could be suppressed to increase cell wall infiltrates under mildly alkaline conditions. This research provides an understanding of the genomic evolution and mechanisms of A. sinodeliciosus in tolerance to saline-alkali environments. The A. sinodeliciosus genome constitutes a valuable resource for evolutionary and ecological studies of Agaricus.

Identification of bHLH family genes in Agaricus bisporus and transcriptional regulation of arginine catabolism-related genes by AbbHLH1 after harvest.

Basic helix-loop-helix (bHLH) transcription factors (TFs) are widely distributed in eukaryotes and play an important role in biological growth and development. The identification and functional analyses of bHLH genes/proteins in edible mushrooms (Agaricus bisporus) have yet to be reported. In the present study, we identified 10 putative bHLH members carrying the conserved bHLH domains. Phylogenetic analyses revealed that the 10 AbbHLHs were the closest to sequences of species belonging to 7 different fungal subgroups, which was supported by loop length, intron patterns, and key amino acid residues. The substantial increase after harvest and continuously elevated expression of AbbHLH1 during the development until the disruption of mushroom velum, and the preferential expression in cap and gill tissues suggest the important function of AbbHLH1 in postharvest development of A. bisporus. The relationship of arginine catabolism-related genes with the early stage of postharvest continuing development also was revealed by expression determination. Subcellular localization showed that AbbHLH1 could be localized in nucleus. Importantly, the electrophoretic mobility shift and dual-luciferase reporter assays showed that AbbHLH1 activated the promoters of AbOAT, AbSPDS, and AbSAMDC and suppressed the expression of AbARG, AbUREA, and AbODC, probably for the modulation of arginine catabolism and thus control of postharvest mushroom development. Taken together, the available data provide valuable functional insight into the role of AbbHLH proteins in postharvest mushrooms.

Mimicking Natural Metabolisms: Cell-Free Flow Preparation of Dopamine.

The biosynthesis of dopamine (DA) from L-tyrosine as starting material is an excellent yet challenging strategy. Here we developed a versatile, multi-enzymatic platform for the biocatalytic preparation of DA in a continuous mode with excellent conversion (90 %) and reaction time (45 min). The system exploits the immobilization of a decarboxylase from Bacillus pumilis (Fdc) and a tyrosinase from Agaricus bisporus (Tyr), which were combined to mimic the in-vivo synthesis of DA (both primary and secondary metabolisms) giving rise to an efficient strategy with a considerable reduction of process associated costs and environmental impact. To enhance the system automation, an in-line purification via catch-and-release procedure was added.

Feeding growing button mushrooms: The role of substrate mycelium to feed the first two flushes.

A number of experiments were done to further our understanding of the substrate utilization in button mushroom crops (Agaricus bisporus). An analysis of the degradation of dry matter of the substrate during a crop cycle revealed that for pin formation the upper 1/3rd layer is used, for the production of flush one all layers are involved and for flush two mainly the lower 1/3 layer is used. A reduction in substrate depth leads to a decrease in yield/m2 but an apparent increase in yield per tonne of substrate with a lower mushroom quality. A short daily interruption of the connection between the casing soil with the substrate results in a delay of the first flush. Interruptions with only part of the substrate did not lead to delay in production. Daily interruption of the connection with all or only part of the substrate leads to a shift in yield from flush one to flush two but the total yield remains unchanged. The mycelial biomass in the substrate increases from filling up to pinning, has a steeper increase during flush one, and is levelling off during flush two, indicating that in the period of venting and up to/including flush one, enzymes are secreted by growing hyphae generating nutrients to feed a fixed amount of mushroom biomass for two flushes. A sidewise extension of the substrate (without casing soil, thus not producing mushrooms) showed that the substrate at a distance more than somewhere between 20-50 cm away from the casing soil does not contribute to feeding mushrooms in the first two flushes. The observations are discussed with respect to relevant previous research.

Gastroprotective effect of hydroalcoholic extract from Agaricus blazei Murill against ethanol-induced gastric ulcer in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: The use of mushrooms in medicine is quite old and the first report about the use of genus Agaricus in treatment of ulcers occurred in Byzantine period. This mushroom is widely consumed as food, tea, food supplements, as well as nutraceutical and cosmeceutical applications, being cultivated and appreciated in several countries such as Brazil, Korea, Japan and China. AIM OF THE STUDY: This study aimed to characterize the chemical profile and the potential gastroprotective effect of hydroalcoholic extract from Agaricus blazei Murill (HEAb). MATERIALS AND METHODS: The extract was chemically characterized by elemental analysis, UPLC-QTOF-MSE, Nuclear Magnetic Resonance (NMR) and high-performance liquid chromatography (HPLC) techniques to elucidate the metabolites present in the extract. The quantification of phenolic compounds and the in vitro antioxidant activities were performed and the gastroprotective effect of this extract was evaluated against ethanol-induced gastric ulcer model. HEAb was administered by gavage at 5, 25 and 50 mg kg-1 and N-acetylcysteine at 300 mg kg-1 (positive control). Furthermore, the pathways of nitric oxide (NO), Cyclic Guanylate Monophosphate (cGMP), prostaglandins (PGs) and the involvement of ATP-sensitive K+ Channels were modulated. RESULTS: Mannitol, malic acid, pyroglutamic acid, L-agaritine and L-valine were putatively identified by UPLC-QTOF-MSE in HEAb. In addition, it was possible to identify mannitol by the intense signals in the NMR spectra, being still quantified as the main compound in the extract by HPLC. The contents of total phenols and flavonoids corroborated with the good antioxidant activity of HEAb. This study observed that HEAb at 25 and 50 mg kg-1 had gastroprotection effect demonstrated by the reduction of histopathological parameters and the reduction of mastocytosis in the stomach of mice. CONCLUSIONS: In this study was possible to conclude that HEAb has gastroprotective effect related to the involvement of NO and PG pathways in the ethanol-induced gastric ulcer model in mice.

A New Biotechnology Method of Bioelements' Accumulation Monitoring in In Vitro Culture of Agaricus bisporus.

Agaricus bisporus (J.E. Lange) Imbach is one the most popular species of edible mushrooms in the world because of its taste and nutritional properties. In the research, repeatability of accumulation of bioelements and biomass yield in experimentally chosen in vitro culture medium, was confirmed. The in vitro cultures were conducted on the modified Oddoux medium enriched with bioelements (Mg, Zn, Cu, Fe). The aim of the study was to create an effective method of sampling, which enabled non-invasive monitoring of metals concentrations changes in the medium, during increase of biomass in in vitro cultures. The first, indirect method of sampling was applied. The non-invasive probe (a dipper) for in vitro culture was used; hence, the highest biomass increase and metals accumulation were gained. The method also guaranteed culture sterility. The second method, a direct one, interfered the in vitro culture conditions and growth of mycelium, and as a consequence the lower biomass increase and metals' accumulation were observed. Few cases of contaminations of mycelium in in vitro cultures were observed. The proposed method of non-invasive sampling of the medium can be used to monitor changes in the concentrations of metals in the medium and their accumulation in the mycelium in natural environment. Changes in concentrations of the selected metals over time, determined by the method of atomic absorption spectrometry, made it possible to correlate the obtained results with the specific stages of A. bisporus mycelium development and to attempt to explain the mechanism of sampling metals from the liquid substrate.

Mating-Type Locus Organization and Mating-Type Chromosome Differentiation in the Bipolar Edible Button Mushroom Agaricus bisporus.

In heterothallic basidiomycete fungi, sexual compatibility is restricted by mating types, typically controlled by two loci: PR, encoding pheromone precursors and pheromone receptors, and HD, encoding two types of homeodomain transcription factors. We analysed the single mating-type locus of the commercial button mushroom variety, Agaricus bisporus var. bisporus, and of the related variety burnettii. We identified the location of the mating-type locus using genetic map and genome information, corresponding to the HD locus, the PR locus having lost its mating-type role. We found the mip1 and ß-fg genes flanking the HD genes as in several Agaricomycetes, two copies of the ß-fg gene, an additional HD2 copy in the reference genome of A. bisporus var. bisporus and an additional HD1 copy in the reference genome of A. bisporus var. burnettii. We detected a 140 kb-long inversion between mating types in an A. bisporus var. burnettii heterokaryon, trapping the HD genes, the mip1 gene and fragments of additional genes. The two varieties had islands of transposable elements at the mating-type locus, spanning 35 kb in the A. bisporus var. burnettii reference genome. Linkage analyses showed a region with low recombination in the mating-type locus region in the A. bisporus var. burnettii variety. We found high differentiation between ß-fg alleles in both varieties, indicating an ancient event of recombination suppression, followed more recently by a suppression of recombination at the mip1 gene through the inversion in A. bisporus var. burnettii and a suppression of recombination across whole chromosomes in A. bisporus var. bisporus, constituting stepwise recombination suppression as in many other mating-type chromosomes and sex chromosomes.

Anthocyanin extract from Lycium ruthenicum enhanced production of biomass and polysaccharides during submerged fermentation of Agaricus bitorquis (Quél.) Sacc. Chaidam.

Agaricus bitorquis (Quél.) Sacc. Chaidam (ABSC) is a wild edible fungus uniquely found in the Tibet Plateau. ABSC is rich in polysaccharides that are considered biologically active. This study aimed to determine the feasibility of enhancing exopolysaccharide (EPS) production by ABSC in shake flask culture by supplementing the fermentation medium with anthocyanin extract. Different concentrations of Lycium ruthenicum Murr. (LRM) anthocyanin crude extract were tested on ABSC fermentation. The activity of phosphoglucose isomerase (PGI), phosphoglucose mutase (PGM), and phosphomannose isomerase (PMI), enzymes presumably involved in EPS synthesis by ABSC, was determined. ABSC transcriptomic profile in response to the presence of anthocyanins during fermentation was also investigated. LRM anthocyanin crude extract (0.06 mg/mL) was most effective in increasing EPS content and mycelial biomass (by 208.10% and 105.30%, respectively, P < 0.01). The activity of PGI, PGM, and PMI was increased in a medium where LRM anthocyanin extract and its main components (proanthocyanidins and petunia anthocyanin) were added. RNA-Seq analysis showed that 349 genes of ABSC were differentially expressed during fermentation in the medium containing anthocyanin extract of LRM; 93 genes were up-regulated and 256 genes down-regulated. From gene ontology enrichment analysis, differentially expressed genes were mostly assigned to carbohydrate metabolism and signal transduction categories. Collectively, LRM anthocyanins extract positively affected EPS production and mycelial biomass during ABSC fermentation. Our study provides a novel strategy for improving EPS production and mycelial growth during ABSC liquid submerged fermentation.

Generation of Iron-Independent Siderophore-Producing Agaricus bisporus through the Constitutive Expression of hapX.

Agaricus bisporus secretes siderophore to uptake environmental iron. Siderophore secretion in A. bisporus was enabled only in the iron-free minimal medium due to iron repression of hapX, a transcriptional activator of siderophore biosynthetic genes. Aiming to produce siderophore using conventional iron-containing complex media, we constructed a recombinant strain of A. bisporus that escapes hapX gene repression. For this, the A. bisporushapX gene was inserted next to the glyceraldehyde 3-phosphate dehydrogenase promoter (pGPD) in a binary vector, pBGgHg, for the constitutive expression of hapX. Transformants of A. bisporus were generated using the binary vector through Agrobacterium tumefaciens-mediated transformation. PCR and Northern blot analyses of the chromosomal DNA of the transformants confirmed the successful integration of pGPD-hapX at different locations with different copy numbers. The stable integration of pGPD-hapX was supported by PCR analysis of chromosomal DNA obtained from the 20 passages of the transformant. The transformants constitutively over-expressed hapX by 3- to 5-fold and sidD, a key gene in the siderophore biosynthetic pathway, by 1.5- to 4-fold in mRNA levels compared to the wild-type strain (without Fe3+), regardless of the presence of iron. Lastly, HPLC analysis of the culture supernatants grown in minimal medium with or without Fe3+ ions presented a peak corresponding to iron-chelating siderophore at a retention time of 5.12 min. The siderophore concentrations of the transformant T2 in the culture supernatant were 9.3-fold (-Fe3+) and 8-fold (+Fe3+) higher than that of the wild-type A. bisporus grown without Fe3+ ions, while no siderophore was detected in the wild-type supernatant grown with Fe3+. The results described here demonstrate the iron-independent production of siderophore by a recombinant strain of A. bisporus, suggesting a new application for mushrooms through molecular biological manipulation.

Investigation on the uptake of ciprofloxacin, chloramphenicol and praziquantel by button mushrooms.

Button mushrooms are widely produced edible basidiomycetes. Commercially, they are cultivated on substrates containing fermented horse manure and chicken feces. Since pharmacologically active substances (PAS) might be introduced into the food chain via animal treatment, their residues may be present in manure used for mushroom growth. Previous studies in plants have demonstrated an uptake of PAS from the agricultural environment. The present study was performed to investigate the presence of PAS in button mushrooms. For analysis, a multi-analyte method for the detection of 21 selected PAS using liquid chromatography tandem-mass spectrometry was developed, successfully validated and applied to commercially available button mushrooms. Traces of chloramphenicol were detected in two of 20 samples. Additionally, in a mushroom cultivation experiment an uptake of ciprofloxacin, chloramphenicol and praziquantel was conducted. Throughout the whole experiment, praziquantel was present in quantifiable amounts in mushrooms and in high quantities in soil.

Polysaccharides and extracts from Agaricus brasiliensis Murill - A comprehensive review.

Edible mushrooms have been increasingly introduced into the human diet, which has driven research into their functional properties. Thus, Agaricus brasiliensis Murill or Agaricus blazei Murill (ABM) is a species native to the Brazilian biome, whose fruiting body has been used not only for dietary purposes, but also in the development of functional foods or as source of molecules of pharmacological interest. The bioactivity of ABM has been related to the presence of polysaccharides, although the contribution of other metabolites cannot be discharged. This work describes the polysaccharides isolation methodology and preparation of the extracts of ABM and their biological activities. Furthermore, it presents a general outline of its characterizations regarding composition, chemical structure and properties in solution. The ABM and its chemical constituents exhibit several biological activities that support their potential use for prevention or treatment of diseases with inflammatory background, such as cancer, diabetes and atherosclerosis. The mechanism of action of the extracts and polysaccharides from ABM is mainly related to a modulation of immune system response or reduction of inflammatory response. This review shows that the ABM has great potential in the pharmaceutical, biotechnological and food sectors that deserves additional research using standardized products.

Enhancing the lithium content of white button mushrooms Agaricus bisporus using LiNO3 fortified compost: effects on the uptake of Li and other trace elements.

Attempts to bio-enrich fungal biomass with an essential trace elements to produce dietary supplements have some tradition and an example is selenium. Lithium salts have medical applications, but safer forms are sought after, and lithiated foods and food supplements may be an alternative. This study evaluated the lithiation of white Agaricus bisporus mushrooms using commercial compost fortified with LiNO3 and investigated the effects on co-accumulation of trace elements. The fortifications at levels of 1.0, 5.0, 10, 50 and 100 mg·kg-1 dw, resulted in corresponding median increases in mushroom Li concentrations of 0.74, 5.0, 7.4, 19 and 21 mg kg-1 dw, respectively, relative to 0.031 mg kg-1 dw in control mushrooms. The bio-concentration potential for Li uptake decreased at higher levels of fortification, with saturation occurring at 100 mg·kg-1, and the level of 500 mg kg-1 mycelium failed to produce mushrooms. The compost fortification resulted in up to several hundred-fold enrichment of mushrooms compared to those grown on control compost, underlining their potential therapeutic use. At higher fortification levels, some effects were seen on the co-accumulation of other elements, such as Ag (stems), As, Cd, Cr, Cs, Cu, Hg (stems), Mn, Rb, Sr, U (stems) and Zn; 0.05 < p < 0.10), but no effects were seen for Ag (caps), Al, Ba, Co, Hg (caps) Ni, Tl, U (caps), and V (p > 0.05).

Valorization of dietary edible mushrooms waste: chemical and physical properties, nutrient digestibility, microbial protein synthesis and nitrogen balance in sheep.

BACKGROUND: The optimal use of feed resources must be considered by most livestock farmers. The use of low-cost agricultural by-products and the processing of these materials is one possible solution in this respect. One such compound is edible button mushroom waste (EM), a large amount of which is produced annually in the mushroom production cycle worldwide. RESULTS: Bulk density 100 of EM was smaller than the other groups. These changes also applied to alfalfa for bulk density, which was higher than the replaced waste. The dry matter solubility of EM was higher than that of alfalfa hay, whereas the ash solubility rate for EM was greater compared to alfalfa. Replacing up to 210 g kg-1 alfalfa with EM did not affect the production of purine derivatives, microbial protein, nitrogen excreted in urine and feces, and retained nitrogen, although the organic matter digestibility (OMD) increased, whereas the crude protein digestibility and neutral detergent fiber (NDF) decreased (P < 0.05). Fermentation potential, gas production rate, metabolizable energy and short-chain fatty acids were increased. On replacing up to 210 g kg-1 alfalfa with EM, the diet OMD increased, whereas the crude protein and NDF digestibility decreased (P < 0.05). CONCLUSION: EM usage in the experimental diets did not affect the production of purine derivatives, microbial protein, nitrogen excreted in urine and feces, and retained nitrogen. The physical properties, chemical composition and nutritional value of EM, as well as its low cost, show that it can be used as an alternative part of the diet forage in the ruminant's diet. © 2021 Society of Chemical Industry.

Influence of cellulose nanocrystals gellan gum-based coating on color and respiration rate of Agaricus bisporus mushrooms.

The edible coating has been used for covering fruits and vegetables, bringing surface protection, and extending product shelf-life. Due to the outstanding properties, nanomaterials have become a part of the packaging/coating new generation, demonstrating improvements in the barrier capacity of materials starting from construction products to the food industry. In the food industry, on the other hand, Agaricus bisporus mushrooms have a limited shelf-life from 1 to 3 days because of their high respiration rate and enzymatic browning. With the aim to reduce these two parameters and prevent rapid senescence, the objective of this study was to incorporate a natural source of nanomaterials (cellulose nanocrystals (CNCs) into a gellan gum-based coating and sprayed the surface of the mushrooms with the coating material. To evaluate the effect of CNCs, oxygen consumption, carbon dioxide production rate, and color change were recorded during the mushroom storage at 4 ± 1 °C. Results showed that all coatings were able to decrease total color change (ΔE) of mushrooms from 12 to 8 at day 10 when the coating was applied in all samples compared to control. In addition, significant differences were observed in the respiration rate when CNCs were added to the mushrooms. Oxygen consumption results exhibited a 44 mL O2 /kg · day production at day 5 with 20% CNCs compared to 269 mL O2 /kg · day observed in noncoated samples. This trend was similarly observed in the carbon dioxide production rate. PRACTICAL APPLICATION: With this research, it was remarkable to see the presence of CNCs in the coating solution reduced the respiration rate and increased the shelf-life of mushrooms. Similar applications can be industrially scaled-up to protect fruits and vegetables by CNCs-based coating or packaging materials. A variety of sustainable materials are available nowadays that serve as packaging matrix, and scientists are working on expanding the compatibility of these nanomaterials. In addition, it has been studied that CNCs enhance the degradation of polymers, an effort that many companies are making to reduce the environmental impact in their products.

The effects of melatonin treatment on cap browning and biochemical attributes of Agaricus bisporus during low temperature storage.

Exogenous melatonin application at 0, 1, 10, 100, and 1000 µM retarded cap browning of button mushrooms (Agaricus bisporus) by 78.35, 31.40, 30.91, 27.17, and 32.50 %, respectively.Mushrooms treated with 100 µM melatonin also had lower weight loss and higher firmness. During the first 5 days of storage at 4 °C, higher H2O2 accumulation may serve as a signal for promoting endogenous melatonin accumulation by triggering the expression of TDC, T5H, SNAT, and ASMT genes, beneficial for preserving membrane integrity. Besides, the higher accumulation of phenols in mushrooms treated with 100 µM melatonin may be ascribed to higher PAL and lower PPO gene expression and enzyme activity. Moreover, higher DPPH scavenging capacity in mushrooms treated with 100 µM melatonin may be ascribed to the higher accumulation of phenols and ascorbic acid.

Melatonin retards senescence via regulation of the electron leakage of postharvest white mushroom (Agaricus bisporus).

Currently, melatonin (N-acetyl-5-methoxytrytamine) is recognized as a potential scavenger of free radicals. In this study, the effect of exogenous melatonin at various concentrations (0.05, 0.1, and 0.2 mM) on the texture, sensory qualities, and electron leakage in white mushrooms was evaluated at 3 ± 1 °C. It was observed that mushrooms treated with 0.1 mM melatonin were of good quality and their electron leakage was dramatically dampened. The results showed that 0.1 mM melatonin retained a higher adenosine triphosphate level and also prevented the release of cytochrome c into the cytoplasm. More significantly, it prominently inhibited electron leakage by increasing the activities of complexes I and III by the upregulation of AbNdufB9 and AbRIP1. It also regulated respiratory states in mushrooms; delayed the decline of respiratory state 3; enhanced respiratory state 4; boosted the oxidative phosphorylation and efficiency of mitochondria; and ultimately retarded the senescence of the white mushrooms.

Isolation and identification of three water-soluble selenoproteins in Se-enriched Agaricus blazei Murrill.

Selenoproteins in selenium (Se)-enriched vegetables play an important role in human health. In this study, three water-soluble selenoproteins PR-Se-1, PR-Se-2 and PR-Se-3 in Agaricus blazei Murrill (ABM) were isolated by anion exchange chromatography, gel filtration chromatography and SDS-PAGE. Sequence analyses performed by HPLC-MS/MS showed that PR-Se-1, a 114024 Da selenoprotein with 1019 amino acids (AAs), is an isoenzyme of isocitrate dehydrogenase. PR-Se-2, a 53983 Da selenoprotein with 508 AAs, is a kind of dihydrolipoyl dehydrogenase. PR-Se-3, a 47179 Da selenoprotein with 415 AAs, is a kind d-proline reductase. Se content is high at 26.1 µg/g, and selenocystine is the predominant Se unit in the three selenoproteins. Se content of ABM is 9.15 µg/g, and the organic form of Se accounts for ~81% of total Se content. ABM could be a promising source of Se in Se-poor regions.