Functional analysis of basidiomycete specific chitin synthase genes in the agaricomycete fungus Pleurotus ostreatus.

Chitin is an essential structural component of fungal cell walls composed of transmembrane proteins called chitin synthases (CHSs), which have a large range of reported effects in ascomycetes; however, are poorly understood in agaricomycetes. In this study, evolutionary and molecular genetic analyses of chs genes were conducted using genomic information from nine ascomycete and six basidiomycete species. The results support the existence of seven previously classified chs clades and the discovery of three novel basidiomycete-specific clades (BI-BIII). The agaricomycete fungus Pleurotus ostreatus was observed to have nine putative chs genes, four of which were basidiomycete-specific. Three of these basidiomycete specific genes were disrupted in the P. ostreatus 20b strain (ku80 disruptant) through homologous recombination and transformants were obtained (Δchsb2, Δchsb3, and Δchsb4). Despite numerous transformations Δchsb1 was unobtainable, suggesting disruption of this gene causes a crucial negative effect in P. ostreatus. Disruption of these chsb2-4 genes caused sparser mycelia with rougher surfaces and shorter aerial hyphae. They also caused increased sensitivity to cell wall and membrane stress, thinner cell walls, and overexpression of other chitin and glucan synthases. These genes have distinct roles in the structural formation of aerial hyphae and cell walls, which are important for understanding basidiomycete evolution in filamentous fungi.

Exploring Therapeutic Potential of Pleurotus ostreatus and Agaricus bisporus Mushrooms against Hyperlipidemia and Oxidative Stress Using Animal Model.

The mushrooms oyster (Pleurotus ostreatus) and white button (Agaricus bisporus) contain bioactive compounds that have potential beneficial effects on hypercholesterolemia and cardiovascular diseases. In this study, hypolipidemic and antioxidative potential of these mushrooms' extract were explored using hypercholesterolemic (HC) rats as animal model. For the study, 56 adult rats were divided into seven groups, i.e., G1 (negative control), G2 (positive control group), G3 (HC rats with statin drug orally), G4 and G5 (HC rats @ 100 and 200 mg/kg body weight (BW) dose of oyster mushroom extracts), and G6 and G7 (HC rats @ 100 and 200 mg/kg BW dose of white button mushroom extracts). The hypercholesterolemia was induced experimentally in fasted rats through a high-fat diet along with injection of triton WR-1339. After 48 h, the treatment groups were given extract for 28 days along with standard diet. At the trial termination, we analyzed the blood sugar levels, antioxidant parameters, lipid profile, and renal function, as well as conducting liver function tests of the rats. The results indicated that positive control group rats exhibited increased levels of total cholesterol (TC), triglycerides (TG), low-density level (LDL), and very-low-density level (vLDL) by 19%, 37%, 52%, and 32%, respectively, and 53% decrease in HDL, whereas treatment groups that received 200 mg oyster and white button mushroom extracts reported 15%, 34%, 22% reduction in TC, TG, vLDL, respectively, and 22% improvement in HDL level. The enzyme profiles of different groups showed non-significant differences, although both mushroom extracts provision reduced glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) levels. Overall, the results indicated that mushroom extracts were helpful in maintaining oxidative stress and have the potential to improve dyslipidemia in the tested rat animal model.

Evaluation of Sample Size Influence on Chemical Characterization and In Vitro Antioxidant Properties of Flours Obtained from Mushroom Stems Coproducts.

The mushroom industry generates large amounts of stem co-product. This is generated after mushroom harvest; stems are attached to the growth substratum, and their only use has traditionally been as compost. In this study, we investigated extensively for the first time this co-product and the influence of sample size (L->0.510 mm; LI-0.510-0.315 mm; SI-0.315-0.180 mm; S-<0.180 mm) on the characterization and antioxidant activity of flours obtained from stem co-products of Agaricus bisporus (ABSF) and Pleurotus ostreatus (POSF). ABSF was rich in protein (14 g/100 g), calcium (428.23-700.77 mg/100 g), and sorbitol (22.57-26.60 g/100 g), while POSF was rich in ß-glucans (36.62-40.34 g/100 g) and linoleic acid (20.57-39.86 g/100 g of lipid). Both species were flush in amino acids and had an umami flavour. ABSF showed more elevated values for emulsifying activity than POSF. The S sizes were highlighted for their yield, hydration properties, and oil holding capacity. Furthermore, ABSF-S exhibited heightened antioxidant capacity in vitro, in consonance with the total phenolic compounds observed (0.91 mg/g). However, the antioxidant assays in POSF presented a positive correlation with ß-glucan content. Our study suggests that these co-products could have several food-related applications, such as potential for use as an emulsifier, sweetener, or fortifier in the development of functional food, owing to their rich concentrations of fibre, protein, sorbitol, and ß-glucans. Nevertheless, it is necessary to understand the interactions of the flours with the potential food matrix prior to proceeding further with food-related applications.

Use of sawdust for production of ligninolytic enzymes by white-rot fungi and pharmaceutical removal.

Use of white-rot fungi for enzyme-based bioremediation of wastewater is of high interest. These fungi produce considerable amounts of extracellular ligninolytic enzymes during solid-state fermentation on lignocellulosic materials such as straw and sawdust. We used pure sawdust colonized by Pleurotus ostreatus, Trametes versicolor, and Ganoderma lucidum for extraction of ligninolytic enzymes in aqueous suspension. Crude enzyme suspensions of the three fungi, with laccase activity range 12-43 U/L and manganese peroxidase activity range 5-55 U/L, were evaluated for degradation of 11 selected pharmaceuticals spiked at environmentally relevant concentrations. Sulfamethoxazole was removed significantly in all treatments. The crude enzyme suspension from P. ostreatus achieved degradation of wider range of pharmaceuticals when the enzyme activity was increased. Brief homogenization of the colonized sawdust was also observed to be favorable, resulting in significant reductions after a short exposure of 5 min. The highest reduction was observed for sulfamethoxazole which was reduced by 84% compared to an autoclaved control without enzyme activity and for trimethoprim which was reduced by 60%. The compounds metoprolol, lidocaine, and venlafaxine were reduced by approximately 30% compared to the control. Overall, this study confirmed the potential of low-cost lignocellulosic material as a substrate for production of enzymes from white-rot fungi. However, monitoring over time in bioreactors revealed a rapid decrease in enzymatic ligninolytic activity.

Postharvest of fresh white shimeji mushroom subjected to UV-C radiation.

This study aimed to evaluate the postharvest characteristics of edible fresh white shimeji mushrooms under different UV-C radiation doses. The experimental design used was fully randomized, in a 5 × 8 factorial scheme (UV-C radiation dose: 0 (control), 1, 2, 3, and 4 kJ m-2 x day of analysis), with 3 replications of 70 ± 1 g mushrooms each. After exposure to different doses, they were stored at 2 ± 0.5 °C and 60 ± 3.8 % RH. Data were subjected to permutational multivariate analysis (PERMANOVA) (p ≤ 0.05). There was no significance for interaction, nor the factor day, only for the UV-C radiation doses factor. Regarding PCA, among the doses applied, the dose of 2 kJ m-2 was effective in maintaining the quality of mushrooms with greater lightness, greater whiteness index, a greater amount of total extractable polyphenols, and total antioxidant activity. In conclusion, the dose of 2 kJ m-2 was effective in maintaining the postharvest quality of white shimeji mushrooms.

Pleurotus ostreatus is a promising candidate of an edible 3D printing ink: Investigation of printability and characterization.

The 3D printing (3DP) technology shows great potential in the food industry, but the development of edible ink is currently insufficient. Pleurotus ostreatus (P. ostreatus) emerges as a novel promising candidate. In this study, a mixed ink was obtained by incorporating butter into P. ostreatus. The effects of different ratios of P. ostreatus and butter, as well as the influence of ink steaming were investigated on 3D printed products. The results indicated that all inks of the P. ostreatus system exhibited positive shear-thinning behavior, and the system maintained stable intermolecular hydrogen bonding when P. ostreatus powder concentration was 40 % (w/v). Furthermore, the L* value of the system was elevated for butter adding. The system with steaming exhibited superior stabilized molecular structure compared to the native system, particularly with a steaming duration of 5 min, showcasing its outstanding supporting capacity. This study suggests that P. ostreatus is a promising candidate in 3DP for the development of an edible ink that promotes innovation and nutritional food.

Microbial Inoculation during the Short-Term Composting Process Enhances the Nutritional and Functional Properties of Oyster Mushrooms (Pleurotus ostreatus).

In recent years, short-term composting techniques have been widely applied in oyster mushroom cultivation, but there is still a lack of systematic research on their impact on the nutritional and functional properties of fruiting bodies. In this study, the microbial inoculant Streptomyces thermoviolaceus BUA-FM01 (ST) was applied in the short-term composting process for oyster mushroom cultivation. The agronomic traits, nutritional composition, flavor compounds, and antioxidant activity of fruiting bodies from the first three flushes were evaluated. The results show that microbial inoculation significantly (p < 0.05) reduced the total carbon content and C/N ratio of the composted substrates and, furthermore, increased the total yield of the fruiting bodies. Moreover, microbial inoculation significantly (p < 0.05) increased the crude protein, crude polysaccharide, total amino acid, and essential amino acid contents of the fruiting bodies. The fruiting bodies of the first flush of ST treatment possessed the highest umami amino acid content and equivalent umami concentration value. Furthermore, microbial inoculation significantly (p < 0.05) enhanced the scavenging ability of crude polysaccharides toward free radicals. The results indicate that microbial inoculation has many benefits for the composting cultivating process of oyster mushrooms and good application prospects.

Protein digestibility and ACE inhibitory activity of fermented flours in older adults and standard gastrointestinal simulation.

Consumption of essential amino acids responsible for muscle protein synthesis is important in preventing sarcopenia among older individuals. This population may experience gastrointestinal disorders that inhibit protein digestibility, making it crucial to address. Therefore, solid-state fermentation (SSF) using Pleurotus ostreatus and air drying has been suggested as a means of improving the protein digestibility of lentils and quinoa. SSF combined with air drying at 70 °C resulted in a slight increase in protein hydrolysis compared to unfermented samples. SSF was found to boost the proportion of small peptides to 35 %. Following digestion, SSF and drying yielded bioactive peptides of 1400 and 450 Da, with a range of 11 % to 28 %, respectively, and peptides < 190 Da making up 60 % of the total. SSF promoted valine, leucine, and isoleucine generation; however, hot air drying reduced free amino acids due to the amino acid-reducing sugar bonding but was never lower than the initial content of its unfermented counterpart. Furthermore, SSF and drying at 70 °C improved the release of hydrophobic amino acids (>70 mg/g dry basis) and negatively charged amino acids (>20 mg/g dry basis) in lentils during digestion. The SSF samples exhibited lower angiotensin converting enzyme (ACE) inhibitory activity, ≤35 %, compared to unfermented flours after digestion. However, the ACE inhibitory activity increased in SSF-dried samples, in part because of melanoidins generated during drying. Finally, lower values of protein digestibility and thus smaller peptides, amino acid profile, and ACE inhibitory activity of fermented flours were found in the older adult digestion model.

Comparative antioxidant activity and phytochemical content of five extracts of Pleurotus ostreatus (oyster mushroom).

Reactive oxygen species reacts with numerous molecules in the body system causing oxidative damage, which requires antioxidants to ameliorate. Pleurotus ostreatus, a highly nutritious edible mushroom, has been reported to be rich in bioactive compounds. This study evaluated the comparative antioxidant activity and phytochemical contents of five extracts of P. ostreatus: aqueous (AE), chloroform (CE), ethanol (EE), methanol (ME) and n-hexane (HE). The phytochemical composition and antioxidant activity of the extracts were determined using standard in-vitro antioxidant assay methods. Results showed that the extracts contained alkaloids, tannins, saponins, flavonoids, terpenoids, phenolics, cardiac glycosides, carbohydrates, anthrocyanins, and betacyanins in varied amounts. CE had the highest flavonoid content (104.83 ± 29.46 mg/100 g); AE gave the highest phenol content of 24.14 ± 0.02 mg/100 g; tannin was highest in EE (25.12 ± 0.06 mg/100 g); HE had highest amounts of alkaloids (187.60 ± 0.28 mg/100 g) and saponins (0.16 ± 0.00 mg/100 g). Antioxidant analyses revealed that CE had the best hydroxyl radical activity of 250% at 100 µg/ml and ferric cyanide reducing power of 8495 µg/ml; ME gave the maximum DPPH activity (87.67%) and hydrogen peroxide scavenging activity (65.58%) at 500 µg/ml; EE had the highest nitric oxide radical inhibition of 65.81% at 500 µg/ml and ascorbate peroxidase activity of 1.60 (iU/l). AE had the best total antioxidant capacity (5.27 µg/ml GAE at 500 µg/ml) and ferrous iron chelating activity (99.23% at 100 µg/ml) while HE gave the highest guaiacol peroxidase activity of 0.20(iU/l). The comparative phytochemical and antioxidant characteristics (IC50) of the extracts followed the order: CE > AE > EE > ME > HE. Overall, chloroform was the best extraction solvent for P. ostreatus. The high content of phenolic compounds, flavonoids, and alkaloids in P. ostreatus makes it a rich source of antioxidants and potential candidate for the development of new therapies for a variety of oxidative stress-related disorders.

Pleurotus ostreatus polysaccharide-mediated modulation of skin damage caused by microcystin-LR in tadpoles.

In this study, we aimed to evaluate the effect of dietary supplementation with edible mushroom (Pleurotus ostreatus)-derived polysaccharides on microcystin leucine-arginine (MC-LR)-induced skin damage in Pelophylax nigromaculatus tadpoles. Tadpoles were exposed to 1 µg/L daily MC-LR, with or without 5.0 g/kg of dietary P. ostreatus polysaccharides, for 30 days. P. ostreatus polysaccharide supplementation significantly increased the dermal collagen fibrils, increased tight junction protein gene expression, decreased the amount of MC-LR accumulation in skin tissues, attenuated oxidative stress, downregulated apoptosis-associated gene transcription, decreased eosinophil numbers, and downregulated transcription of inflammation-related genes (e.g. TLR4, NF-κB, and TNF-α). The composition of the skin commensal microbiota of MC-LR-exposed tadpoles supplemented with P. ostreatus polysaccharides was similar to that of the no-treatment control group. Lipopolysaccharide (LPS) content was positively correlated with the abundance of Gram-negative bacteria, including Chryseobacterium and Thauera. Therefore, P. ostreatus polysaccharides may alleviate MC-LR-induced skin barrier damage in tadpoles in two ways: 1) attenuation of oxidative stress-mediated apoptosis mediated by increased glutathione (GSH) content and total superoxide dismutase activity; and 2) alteration of the skin commensal microbiota composition to attenuate the LPS/Toll-like receptor 4 inflammatory pathway response. Furthermore, P. ostreatus polysaccharides may increase skin GSH synthesis by promoting glycine production via the gut microbiota and may restore the MC-LR-damaged skin resistance to pathogenic bacteria by increasing antimicrobial peptide transcripts and lysozyme activity. This study highlights for the first time the potential application of P. ostreatus polysaccharides, an ecologically active substance, in mitigating the skin damage induced by MC-LR exposure, and may provide new insights for its further development in aquaculture.

Comparative Proteomic Analysis Reveals Candidate Pathways Related to the Effect of Different Light Qualities on the Development of Mycelium and Fruiting Body of Pleurotus ostreatus.

Light affects the morphology and physiology of Pleurotus ostreatus. However, the underlying molecular mechanism of this effect remains unclear. In this study, a label-free comparative proteomic analysis was conducted to investigate the global protein expression profile of the mycelia and fruiting bodies of P. ostreatus PH11 growing under four different light quality treatments. Among all the 2234 P. ostreatus proteins, 1349 were quantifiable under all tested conditions. A total of 1100 differentially expressed proteins were identified by comparing the light group data with those of the darkness group. GO and KEGG enrichment analyses indicated that the oxidative phosphorylation, proteasome, and mRNA surveillance pathways were the most related pathways under the light condition. qRT-PCR verified that the expression of the white collar 1 protein was significantly enhanced under white light. Additionally, glutamine synthetase and aldehyde dehydrogenase played important roles during light exposure. This study provides valuable insight into the P. ostreatus light response mechanism, which will lay the foundation for improved cultivation.

Preparation, physicochemical and biological evaluation of chitosan Pleurotus ostreatus polysaccharides active films for food packaging.

The aim of this study was to create CS-POP composite films by blending Pleurotus ostreatus stalk polysaccharides (POP) and chitosan (CS). The effects of adding different concentrations (0 %, 0.25 %, 0.5 %, 0.75 %, and 1 %) of POP on the mechanical, barrier, and optical properties of the CS films were investigated. When the POP content is at 0.5 %, the tensile strength of the composite film reaches its maximum value at 13.691 MPa, showing a significant improvement compared to the tensile strength of the pure CS film. The structure of the CS and CS-POP composite films was characterized by FT-IR spectroscopy, XRD, TGA and SEM. The results indicate that due to the interaction between the two types of CS and POP, the formation of Schiff base, and the intermolecular hydrogen bonds between CS and POP, the addition of POP to CS films can result in a smoother and more stable crystalline structure in the composite film. The CS-POP composite films exhibited enhanced antioxidant and antibacterial activity compared to the CS films alone, with the highest DPPH scavenging activity of 72.43 %. The composite films also showed significant inhibitory effects on the growth of E. coli.

In situ mycoremediation of acid rain and heavy metals co-contaminated soil through microbial inoculation with Pleurotus ostreatus.

The combined pollution of acid rain and heavy metals in soil is a pressing environmental problem, especially in the regions with large-scale heavy industrial production activities. Low remediation efficiency and weak long-lasting stability are major challenges when disposing the heavy metals contaminated soil in acid rain polluted sites. Herein, a specific microbe, strain CT13 was isolated and domesticated to exhibit high tolerance to both acid rain and cadmium (Cd). Then, an in situ mycoremediation method by adopting a bioaugmentation technology of strain CT13 inoculation with Pleurotus ostreatus was developed. The remediation performance was investigated in acidic conditions with Cd concentrations in soil ranging from 0 to 15 mg/kg. While most of the bacteria strains (e.g. strain CT6/13) significantly improved the dry weight of mushroom and Cd accumulation in neutral environment, the performance of strain CT6 was remarkably deteriorated in acid rain environment. In contrast, strain CT13 maintained its behavior in acidic conditions, displaying ∼30 % and 150 % enhancements (vs the neutral environment) in the dry weight of mushroom and Cd accumulation, respectively. In addition, inoculation of strain CT13 led to significant reductions in the content of superoxide dismutase, peroxidase and lipid peroxidation in the fruiting body of P. ostreatus, indicating an improvement in the mushroom's tolerance to both acid rain and heavy metals. The synergistic effect of strain CT13 and P. ostreatus realized the significant improvement in soil remediation efficiency and long-lasting stability in acidic conditions, providing valuable insights into the remediation of heavy metal contaminated soil in the regions affected by acid rain.

Development of novel heat-treated sausage with Pleurotus ostreatus: Low energy, enhanced bioactivity, reduced amount of meat and fat.

The use of Pleurotus ostreatus to reduce calories and increase bioactivity in processed meat products is an increasingly common practice. In this study, a novel sausage containing P. ostreatus was developed based parameters like protein, antioxidants, total phenolic content, cohesiveness, energy, fat, ΔE, hardness, and gumminess values using a D-optimal mixture design. The results showed that over 20% of P. ostreatus could be used in sausage production. Moreover, it was concluded that the optimized sausages contain less fat (33.05%) and meat (18.6%) and therefore have a lower calorie value (19.03%). In addition, P. ostreatus added to the sausage formulation decreased the use of animal raw materials, increased the bioactive properties of the sausages, and did not cause a significant change in the amino acid profile.

Investigation of pre-treatment techniques on spent substrate of Pleurotus ostreatus for enhanced biobutanol production using Clostridium acetobutylicum MTCC 11274.

Addressing global energy demand, researchers sought eco-friendly biobutanol production from lignocellulosic waste biomass. In the present research work, five different pre-treatment methods viz., Microwave, Ultrasound, Alkali, Acid, and Hybrid, were investigated to explore its biobutanol production potential by utilizing Pleurotus ostreatus spent as substrate. The compositional and physico-chemical changes of the pre-treated Spent Mushroom Substrate (SMS) were assessed using SEM, FTIR, and XRD. Hybrid pre-treatment (Microwave, Alkali, Ultrasound) showed higher delignification when compared to conventional pre-treatment method. Hybrid pre-treated SMS resulted in higher total reducing sugars (521.53 ± 1.84 mg/g) than indigenous SMS (267.89 ± 1.53 mg/g). Fermentation of hybrid pre-treated SMS with Clostridium acetobutylicum MTCC 11274 produced the highest biobutanol concentration (9.84 ± 0.03 g/L) and yielded 0.38 ± 0.02 g/g of biobutanol. This study revealed that hybrid pre-treatment could be a promising solution for enhanced biobutanol production using SMS biomass.

Consuming Mushrooms When Adopting a Healthy Mediterranean-Style Dietary Pattern Does Not Influence Short-Term Changes of Most Cardiometabolic Disease Risk Factors in Healthy Middle-Aged and Older Adults.

BACKGROUND: Mushrooms are a nutritious food, though knowledge of the effects of mushroom consumption on cardiometabolic risk factors is limited and inconsistent. OBJECTIVE: We assessed the effects of consuming mushrooms as part of a healthy United States Mediterranean-style dietary pattern (MED) on traditional and emerging cardiometabolic disease (CMD) risk factors. We hypothesized that adopting a MED diet with mushrooms would lead to greater improvements in multiple CMD risk factors. METHODS: Using a randomized, parallel study design, 60 adults (36 females, 24 males; aged 46 ± 12 y; body mass index 28.3 ± 2.84 kg/m2, mean ± standard deviation) without diagnosed CMD morbidities consumed a MED diet (all foods provided) without (control with breadcrumbs) or with 84 g/d of Agaricus bisporus (White Button, 4 d/wk) and Pleurotus ostreatus (Oyster, 3 d/wk) mushrooms for 8 wk. Fasting baseline and postintervention outcome measurements were traditional CMD risk factors, including blood pressure and fasting serum lipids, lipoproteins, glucose, and insulin. Exploratory CMD-related outcomes included lipoprotein particle sizes and indexes of inflammation. RESULTS: Adopting the MED-mushroom diet compared with the MED-control diet without mushrooms improved fasting serum glucose (change from baseline -2.9 ± 1.18 compared with 0.6 ± 1.10 mg/dL; time × group P = 0.034). Adopting the MED diet, independent of mushroom consumption, reduced serum total cholesterol (-10.2 ± 3.77 mg/dL; time P = 0.0001). Concomitantly, there was a reduction in high-density lipoprotein (HDL) cholesterol, buoyant HDL2b, and apolipoprotein A1, and an increase in lipoprotein(a) concentrations (main effect of time P < 0.05 for all). There were no changes in other measured CMD risk factors. CONCLUSIONS: Consuming a Mediterranean-style healthy dietary pattern with 1 serving/d of whole Agaricus bisporus and Pleurotus ostreatus mushrooms improved fasting serum glucose but did not influence other established or emerging CMD risk factors among middle-aged and older adults classified as overweight or obese but with clinically normal cardiometabolic health. TRIAL REGISTRATION NUMBER: https://www. CLINICALTRIALS: gov/study/NCT04259229?term=NCT04259229&rank=1.

Ensayo de citotoxicidad de extractos de Pleurotusostreatus en diferentes líneas celulares para aplicaciones inmunonutricionales

Introducción: Los bioderivados propuestos como candidatos a ingredientes alimentarios suelen requerir ciertas evaluaciones para las aplicaciones inmunonutricionales Los hongos comestibles-medicinales son un surtidor de compuestos con estas potencialidades. Entre ellos, las setas Pleurotus ostreatus contienen metabolitos bioactivos, con importantes usos en la industria alimenticia y en la práctica terapéutica de la industria médico-farmacéutica. Los ensayos de citotoxicidad in vitro constituyen métodos valiosos para evaluarproductos de origen natural, como los extractos fúngicos. Objetivo: Evaluar la citotoxicidad de dos extractos obtenidos de la seta Pleurotus ostreatus en diferentes líneas celulares. Método: Se obtuvieron extractos hidrosolubles a partir del micelio y de los cuerpos fructíferos de Pleurotus ostreatus en laboratorios del Centro de Estudios de Biotecnología Industrial de la Universidad de Oriente. Se evaluó la citotoxicidad de los bioproductos por el ensayo de reducción del colorante resazurina sobre tres líneas celulares en el Laboratorio de Microbiología, Parasitología e Higiene (LMPH) de la Universidad de Amberes, Bélgica. Se utilizaron células no adherentes THP-1 (pre-monocitos de leucemia humana), células adherentes Caco-2 (epitelio de adenocarcinoma de colon humano) y células adherentes RAW 264.7 (macrófagos murinos). Resultados: Los extractos de Pleurotus ostreatus no resultaron citotóxicos para ninguna de las líneas celulares estudiadas humanas o murina, ya que no ocasionaron daños sobre la viabilidad de las célulasepiteliales del sistema gastrointestinal, nisobrelas células del sistema inmune empleadas. Conclusiones: Este resultado demuestra que ambos bioderivados fúngicos pueden ser aplicados con seguridad en estudios inmunonutricionales.

Introduction: Bioderivatives proposed as candidates for food ingredients usually require certain evaluations for immunonutritional applications. Edible-medicinal mushrooms are a source of compounds with these potentials. Among them, Pleurotus ostreatus mushrooms contain bioactive metabolites, with important uses in the food industry and in the therapeutic practice of the medical-pharmaceutical industry. In vitro cytotoxicity assays are valuable methods to evaluate products of natural origin, such as fungal extracts. Objective: To evaluate the cytotoxicity of two extracts obtained from the Pleurotus ostreatus mushroom in different cell lines. Method: Water-soluble extracts were obtained from the mycelium and fruiting bodies of Pleurotus ostreatus in laboratories of the Center for Industrial Biotechnology Studies of the Universidad de Oriente. The cytotoxicity of the bioproducts was evaluated by the resazurin dye reduction assay on three cell lines at the Laboratory of Microbiology, Parasitology and Hygiene (LMPH) of the University of Antwerp, Belgium. Non-adherent THP-1 cells (human leukemia pre-monocytes), Caco-2 adherent cells (human colon adenocarcinoma epithelium) and RAW 264.7 adherent cells (murine macrophages) were used. Results: Pleurotus ostreatus extracts were not cytotoxic for any of the human or murine cell lines studied, since they did not cause damage to the viability of the epithelial cells of the gastrointestinal system, nor to the immune system cells used. Conclusions: This result demonstrates that both fungal bioderivatives can be safely applied in immunonutritional studies.

Introdução: Bioderivados propostos como candidatos a ingredientes alimentícios geralmente requerem determinadas avaliações para aplicações imunonutricionais. Pleurotus ostreatus contêm metabólitos bioativos, com importantes utilizações na indústria alimentícia e na prática terapêutica da indústria médico-farmacêutica. Ensaios de citotoxicidade in vitro são métodos valiosos para avaliar produtos de origem natural, como extratos de fungos. Objetivo: Avaliar a citotoxicidade de dois extratos obtidos do cogumelo Pleurotus ostreatus em diferentes linhagens celulares. Método: Extratos hidrossolúveis foram obtidos do micélio e dos corpos frutíferos de Pleurotus ostreatus nos laboratórios do Centro de Estudos de Biotecnologia Industrial da Universidade de Oriente. A citotoxicidade dos bioprodutos foi avaliada pelo ensaio de redução do corante resazurina em três linhagens celulares no Laboratório de Microbiologia, Parasitologia e Higiene (LMPH) da Universidade de Antuérpia, Bélgica. Foram utilizadas células THP-1 não aderentes (pré-monócitos de leucemia humana), células aderentes Caco-2 (epitélio de adenocarcinoma do cólon humano) e células aderentes RAW 264.7 (macrófagos murinos). Resultados: Os extratos de Pleurotus ostreatus não foram citotóxicos para nenhuma das linhagens celulares humanas ou murinas estudadas, pois não causaram danos à viabilidade das células epiteliais do sistema gastrointestinal, nem às células do sistema imunológico utilizadas. Conclusões: Este resultado demonstra que ambos os bioderivados fúngicos podem ser aplicados com segurança em estudos imunonutricionais.

PriA is involved in Pleurotus ostreatus development and defense against Pseudomonas tolaasii.

Pleurotus ostreatus is a crucial commercial mushroom widely cultivated for diverse uses. Scientists have worked on breeding disease-resistant and high-yielding varieties to secure food supply. Studies on the molecular genetic mechanism of growth and development can provide valuable information to facilitate crop breeding programs by genetic engineering. Aegerolysins are pore-forming proteins widely distributed in both prokaryotes and eukaryotes, which are reported to have haemolytic activity and be involved in the early stages of fructification. The present study aimed to explore biological function of a differential expressed aegerolysin gene PriA in P. ostreatus. The expression level of PriA gene was higher in primordium and fruiting body than that in mycelium. The PriA expression in overexpression (OE) and RNAi interference (RNAi) strains was detected by qRT-PCR. The RNAi strains grew at slightly slower rates and advanced producing yellow pigments than the wild type, while OE strains showed no prominent phenotypic characteristics. Furthermore, Pseudomonas tolaasii infection assays showed that the PriA OE strains could enhance mycelia and caps resistance to P. tolaasii. These data demonstrate PriA from P. ostreatus play an essential role in mycelial development and increase antagonism against P. tolaasii. Our study provides some reference information on interactions between edible fungi and pathogenic bacteria and offers a new resistance-conferring gene for breeding.

Identification of two phthalide derivatives and an oxindole compound isolated from the edible mushroom Pleurotus ostreatus and their inhibitory activities against plant pathogenic microorganisms.

The excessive use of chemical pesticides in agricultural fields for controlling plant pathogenic microorganisms harms human health, the environment, and other beneficial microorganisms in the soil and plants. To address this challenge, it is essential to isolate and discover bioactive compounds from biological resources that could inhibit plant pathogenic microorganisms. In this study, the culture filtrate of the edible mushroom Pleurotus ostreatus was subjected to bioassay-guided isolation, and two phthalide derivatives-4,6-dimethoxyphthalide (1) and 5,7-dimethoxyphthalide (2)-were identified, along with an oxindole compound-3-hydroxy-3-methyloxindole (3). The inhibitory activities of the three compounds were evaluated against four fungal and five bacterial pathogens. Remarkably, 1 and 2 exhibited the lowest IC50 values against the conidial germination and germ tube elongation of the rice blast fungus Pyricularia oryzae. However, their effectiveness against bacterial pathogens was relatively low. The (S) and (R)-enantiomers of 3-hydroxy-3-methyloxindole showed different activities against plant fungal pathogens and bacterial plant pathogens.

Properties of Yogurts Enriched with Crude Polysaccharides Extracted from Pleurotus ostreatus Cultivated Mushroom.

Increasingly, consumers are looking for products with specific nutritional and health-promoting properties. The answer of the producers for this demand is fortified food. The raw material that can be used to enrich food is, among others, mushrooms. Crude water soluble polysaccharides (cWSP) were isolated from fruiting bodies of Pleurotus ostreatus (oyster) mushroom. Chemical analysis showed that they consisted mainly of carbohydrates (~61%), protein (~9%) and phenolics (~0.8%). The isolated cWSP were used to obtain enriched cow milk set yogurts. cWSP were added at the concentration of 0.1%, 0.2%, 0.3%, 0.4% and 0.5%, and milk containing no cWSP was prepared as the control. All of the variants were fermented via applying two commercially available culture starters. The addition of cWSP led to a drop in pH in the case of one starter culture. Also, the decline in total soluble solids (TSS) content was higher where cWSP was used for the enrichment. Texture profile analysis (TPA) revealed that parameters of hardness and gumminess increased along with the concentration of cWSP (reaching values approximately 7-8 times higher, compared to the control). A significant increase in syneresis level (proportional to cWSP concentration and ranging from ~10% to ~50%) was also observed after the fermentation. Fortifying milk with cWSP led to a slight increase in antioxidant capacity in FRAP assay (up to ~12%) and ABTS assay (up to ~23%). The results demonstrate that using cWSP to enrich set-type yogurts is fairly limited.