Toxic elements and trace elements in Macrolepiota procera mushrooms from southern Spain and northern Morocco

Effects of legacy mining on mercury concentrations in conifer needles and mushrooms in northern Palatinate, Germany

Due to integrated pollution prevention and control measures and the reduced burning of coal, air concentrations of mercury (Hg0) are currently levelling off. In the future, however, evasion from land surfaces will probably reverse this trend. Reasons are the rising temperatures and the loss of forest cover caused by calamities, droughts, storms and wildfires. Plant leaves constitute an important matrix for the accumulation of gaseous mercury and uptake and re-volatilisation by plants depends on the species, the vitality and the age and morphology of leaf organs. It has been shown that older conifer needles show higher concentrations than young needles and Hg accumulation is increasing throughout the season. In present study, we collected branches from Norway Spruce (Picea abies) in a former cinnabar mining region in Northern Palatinate, where artisanal and small-scale mining left innumerable waste dumps. While mining, smelting and processing of the ores were terminated during WWII, high total mercury concentrations remained in the top soils locally, with presumably only small fractions being plant available. In the lab, up to seven needle age classes were analysed. 1000 needle weights increased with age and as expected, also the Hg concentrations were elevated in the older needles. Needle concentrations were higher than those reported from other national biomonitoring programs confirming the regional imprint from legacy mercury. To complement our biomonitoring study, we collected edible mushrooms in former mining areas. Hg concentrations in most samples exceeded the EU maximum residue levels (MRL), while only a few broke the existing cadmium and lead limits. Tolerable weekly intake (TWI) for inorganic mercury would be surpassed with the consumption of a small portion of mushrooms. Further studies should be performed on the outgassing of Hg from mine wastes and the incorporation of Hg in the local food web, including its methylation and biomagnification.

Metals Transfer in Mushroom Tricholoma matsutake from Regional High Geochemical Background Areas: Environmental Influences and Human Health Risk

Wild-grown edible mushrooms are important in world diets and are also efficient metal accumulators. Yunnan, Southwest China, is the main producing region, with typically high levels of geochemical metals. The environmental factors, bioaccumulation, distribution and human health risks of metals were examined in paired soil and Tricholoma matsutake (n = 54). T. matsutake grows on acidified soils (pH = 3.95-6.56), and metals show a strong heterogeneity, with Fe, Mn, Zn and Cu in the ranges of 16-201, 0.046-8.58 g kg-1, and 22.6-215, 3.7-155 mg kg-1. High soil Fe content led to great accumulation in T. matsutake (0.24-18.8 g kg-1). However, though the soil Mn content was higher than that of Zn and Cu, their concentrations in T. matsutake were comparable (21.1-487 vs. 38.7-329 and 24.9-217 mg kg-1). This suggested that T. matsutake prefers to accumulate Zn and Cu compared to Mn, and this is supported by the bioaccumulation factors (BAFs = 0.32-17.1 vs. 0.006-1.69). Fe was mainly stored in stipes, while Mn, Zn and Cu were stored in caps, and the translocation factors (TFs) were 0.58 vs. 1.28-1.94. Therefore, stipe Fe showed the highest health risk index (HRI) at 1.28-26.9, followed by cap Cu (1.01-2.33), while 98-100% of the Mn and Zn were risk-free. The higher concentration and greater risk of Fe was attributed to the significant effect of soil Fe content (R = 0.34) and soil pH (R = -0.57). This study suggested that Fe, as an essential mineral, may exert toxic effects via the consumption of T. matsutake from high geochemical background areas.

Selected detrimental and essential elements in fruiting bodies of culinary and toxic medicinal macroscopic fungi growing in the Bohemian Forest, the Czech Republic

Selected wild-growing edible fungi (Boletus edulis, Neoboletus luridiformis, Cantharellus cibarius, Macrolepiota procera, Amanita rubescens, Russula virescens, Lycoperdon perlatum, and Flammulina velutipes) along with the poisonous medicinal species Amanita muscaria were collected from five sites in the Bohemian Forest, the Czech Republic and analyzed regarding the contents of 19 elements (Ag, Al, As, Be, Ca, Cd, Co, Cr, Cu, Fe, Li, Mg, Mn, Ni, Pb, Rb, Se, Tl, and Zn) in their fruiting bodies. The contents of the elements as well as bioconcentration factors (ratios of the element content in dry matter of the mushroom to the content in the soil; BCF) were significantly species dependent. In general, the analysis revealed the most intensive accumulation of Cd, Rb, Ag, Cu, Se, and Zn in the studied mushrooms. B. edulis accumulated Ag, Se, Cd, Rb, Cu, and Zn with average BCF of 31, 25, 18, 13, 3.9, and 2.6, respectively. On the other hand, A. rubescens accumulated Cd, Rb, Ag, Cu, Zn, and As (BCF of 41, 27, 4.8, 3.3, 2.1, and 1.4). The data concerning the detrimental elements in sporocarps of edible mushrooms indicate no negative effect on human health if the fungi are consumed occasionally or as a delicacy.

Application of Diffusive Gradients in Thin-films (DGT) for assessing the heavy metals mobility in soil and prediction of their transfer to Russula virescens

Although edible mushrooms are considered a source of many beneficial nutrients for human, they can also represent a risk to health due to their capacity to accumulate heavy metals. In this study, the total dissolved in soil solution and labile concentrations of heavy metals (Cd, Pb, Cu, Zn, Co, Cr, Mn, Ni, and Fe) in soil were measured and correlated with their concentrations accumulated in Russula virescens wild mushrooms. The diffusive gradient in thin films (DGT) technique was used to measure the labile metals content in the soil (CDGT), and corroborated with the metals concentrations in soil solution (Csoln) was used to calculate an R-value, which can estimate the metals resupply from soil solid phase when they are uptake by mushroom. The DGT-labile metal concentrations decreased in the order Mn > Fe > Zn > Cu > Co > Ni > Cd ≅ Pb > Cr. The R-values, calculated as the ratio between CDGT and Csoln decreased in the order: Cd (0.50) > Zn (0.37) > Pb (0.33) > Cu (0.24) ≅ Ni (0.24) ≅ Co (0.23) > Mn (0.16) > Fe (0.12) > Cr (0.04). For the first time, we compared the R-values with the bioaccumulation factors (BAFs) in mushrooms, and it was observed that, a similar increasing trend of BAFs with the R-values exists, thus the capacity of the soil solid phase to fast re-supply metals to soil solution increases BAFs. Although the soil samples were not contaminated with heavy metals above the legislative limits, the concentrations of heavy metals accumulated in mushrooms were high enough to pose risks for humans, mainly for children, due to their Cu content.

Chromium contents, distribution and bioaccessibility in cultivated mushrooms from market: Health implications for human consumption

Mushrooms are consumed worldwide as they constitute a part of traditional cuisine culture in many countries. However, chromium (Cr) accumulation in mushrooms may constitute a potential pathway for its chronical exposure to humans. In this work, the Cr contents, distribution and bioaccessibility in 140 cultivated mushrooms from 14 species in 10 top-producing provinces in China were examined. Total Cr contents were 0.09-4.71 mg·kg-1 dw (mean 0.74 mg kg-1), with 59% exceeding the 0.5 mg kg-1standard. Additionally, less Cr was accumulated in the caps than stipes, with Cr ratio in caps/stipes being 0.28-2.6, averaging 0.91. Based on the Solubility Bioaccessibility Research Consortium (SBRC) assay, the mean Cr bioaccessibility in the mushrooms was 24.8% and 50.1% in the gastric phase (GP) and intestinal phase (IP). However, samples from Guizhou show the lowest Cr bioaccessibility at 12.5% in GP and 24.8% in IP. Further, a negative correlation between total Cr contents and Cr bioaccessibility suggests that Cr bioaccessibility is critical for accurate assessment of Cr exposure. In addition, drying mushrooms increased their bioaccessibility in the gastric phase. This study shows a high Cr exceeding rate of cultivated mushrooms, which may indicate a potential exposure risk, with Cr contents and bioaccessibility showing species and regional variation.

Fungal bioproducts for petroleum hydrocarbons and toxic metals remediation: recent advances and emerging technologies

Petroleum hydrocarbons and toxic metals are sources of environmental contamination and are harmful to all ecosystems. Fungi have metabolic and morphological plasticity that turn them into potential prototypes for technological development in biological remediation of these contaminants due to their ability to interact with a specific contaminant and/or produced metabolites. Although fungal bioinoculants producing enzymes, biosurfactants, polymers, pigments and organic acids have potential to be protagonists in mycoremediation of hydrocarbons and toxic metals, they can still be only adjuvants together with bacteria, microalgae, plants or animals in such processes. However, the sudden accelerated development of emerging technologies related to the use of potential fungal bioproducts such as bioinoculants, enzymes and biosurfactants in the remediation of these contaminants, has boosted fungal bioprocesses to achieve higher performance and possible real application. In this review, we explore scientific and technological advances in bioprocesses related to the production and/or application of these potential fungal bioproducts when used in remediation of hydrocarbons and toxic metals from an integral perspective of biotechnological process development. In turn, it sheds light to overcome existing technological limitations or enable new experimental designs in the remediation of these and other emerging contaminants.

Essential Mineral Content (Fe, Mg, P, Mn, K, Ca, and Na) in Five Wild Edible Species of Lactarius Mushrooms from Southern Spain and Northern Morocco: Reference to Daily Intake

Mushroom consumption has increased in recent years due to their beneficial properties to the proper functioning of the body. Within this framework, the high potential of mushrooms as a source of essential elements has been reported. Therefore, the present study aims to determine the mineral content of seven essential metals, Fe, Mg, Mn, P, K, Ca, and Na, in twenty samples of mushrooms of the genus Lactarius collected from various locations in southern Spain and northern Morocco, by FAAS, UV-Vis spectroscopy, and ICP-OES after acid digestion. Statistics showed that K was the macronutrient found at the highest levels in all mushrooms studied. ANOVA showed that there were statistically significant differences among the species for K, P, and Na. The multivariate study suggested that there were differences between the accumulation of the elements according to the geographic location and species. Furthermore, the intake of 300 g of fresh mushrooms of each sample covers a high percentage of the RDI, but does not meet the recommended daily intake (RDI) for any of the metals studied, except for Fe. Even considering these benefits, the consumption of mushrooms should be moderated due to the presence of toxic metals, which may pose health risks.

A Coding Basis and Three-in-One Integrated Data Visualization Method 'Ana' for the Rapid Analysis of Multidimensional Omics Dataset

With innovations and advancements in analytical instruments and computer technology, omics studies based on statistical analysis, such as phytochemical omics, oilomics/lipidomics, proteomics, metabolomics, and glycomics, are increasingly popular in the areas of food chemistry and nutrition science. However, a remaining hurdle is the labor-intensive data process because learning coding skills and software operations are usually time-consuming for researchers without coding backgrounds. A MATLAB® coding basis and three-in-one integrated method, 'Ana', was created for data visualizations and statistical analysis in this work. The program loaded and analyzed an omics dataset from an Excel® file with 7 samples * 22 compounds as an example, and output six figures for three types of data visualization, including a 3D heatmap, heatmap hierarchical clustering analysis, and principal component analysis (PCA), in 18 s on a personal computer (PC) with a Windows 10 system and in 20 s on a Mac with a MacOS Monterey system. The code is rapid and efficient to print out high-quality figures up to 150 or 300 dpi. The output figures provide enough contrast to differentiate the omics dataset by both color code and bar size adjustments per their higher or lower values, allowing the figures to be qualified for publication and presentation purposes. It provides a rapid analysis method that would liberate researchers from labor-intensive and time-consuming manual or coding basis data analysis. A coding example with proper code annotations and completed user guidance is provided for undergraduate and postgraduate students to learn coding basis statistical data analysis and to help them utilize such techniques for their future research.

Quantitative mapping of mercury and selenium in mushroom fruit bodies with laser ablation-inductively coupled plasma-mass spectrometry

This work describes the development of a novel method for quantitative mapping of Hg and Se in mushroom fruit body tissues with laser ablation coupled to inductively coupled plasma-mass spectrometry (LA-ICP-MS). Different parameters of the protocol for preparation of the standards used for quantification via external calibration were assessed, e.g., the dissolution temperature of gelatin standards and the addition of chitosan and L-cysteine as additives to the gelatin-based calibration droplets to better match the sample matrix. While chitosan was not suited for this purpose, the presence of L-cysteine considerably improved the figures of merit of the calibration, leading to limits of detection of 0.006 and 0.3 µg g-1 for Hg and Se, respectively, at a pixel size of 20 × 20 µm. Further, an in-house reference material, ideally suited for the validation of the method for application to mushroom samples, was successfully prepared from a paste of Boletus edulis. The newly developed method was used to investigate the distribution of Hg and Se in tissue sections of five porcini mushroom individuals of three different species (Boletus edulis, Boletus aereus, and Boletus pinophilus) and one sample of a parasol mushroom (Macrolepiota procera). For one sample, additional areas were ablated at higher spatial resolution, with a laser spot size down to 5 µm, which allows a detailed investigation of the spatial distribution of Hg and Se in mushrooms.

Risk Assessment of Heavy Metals Occurrence in Two Wild Edible Oyster Mushrooms (Pleurotus spp.) Collected from Rajaji National Park

This study aimed at assessing the concentration of six heavy metals (Cd, Cr, Cu, Fe, Mn, and Zn) in two wild edible oyster mushrooms (Pleurotus ostreatus and Pleurotus djamor) collected from Rajaji National Park in Haridwar, India. For this purpose, mushroom samples were collected from selected locations (forest, residential, tourist, industrial areas, and transportation activities) from June 2021 to July 2022 and subsequently analyzed for selected heavy metals using atomic absorption spectroscopy (AAS). Results showed that both Pleurotus spp. had significantly varying (p < 0.05) concentrations of heavy metals. However, P. ostreatus showed relatively higher concentration levels of these metals compared to P. djamor. The mean concentrations (mg/kg dry weight) of the Cd, Cr, Cu, Fe, Mn, and Zn in P. ostreatus and P. djamor were 0.10 and 0.08, 0.87 and 0.64, 16.19 and 14.77, 28.49 and 27.15, 9.93 and 8.73, and 18.15 and 15.76, respectively. As indicated by the multivariate analysis tools i.e., principal component analysis (PCA) and hierarchical cluster analysis (HCA), the locations near the residential, industrial, and transportation activities had higher concentration levels of heavy metals. Moreover, the health risk studies using the target hazard quotient (THQ < 1) showed no significant health risk as the consumption of both Pleurotus spp., except for at one location, had high-traffic activities. The findings of this study provide vital information about the occurrence of potentially toxic heavy metals in wild edible Pleurotus spp. in Rajaji National Park in Haridwar, India representing a safeguard for mushroom consumers.

Structural Features and Immunomodulatory Effects of Water-Extractable Polysaccharides from Macrolepiota procera (Scop.) Singer

Macrolepiota procera (MP) is an edible mushroom used in the treatment of diabetes, hypertension and inflammation. However, the structure and biological effects of its polysaccharides (PSs) are unclear. This study investigates the structural features of a PS complex from MP (MP-PSC), its immunomodulatory activities and effects on probiotic and pathogenic bacteria. MP-PSC was obtained by boiling water, and PSs were characterized by 2D NMR spectroscopy. The immunomodulatory effects on blood and derived neutrophils, other leukocytes, and murine macrophages were studied by flow cytometry, chemiluminescence, spectrophotometry, and ELISA. The total carbohydrate content of MP-PSC was 74.2%, with glycogen occupying 36.7%, followed by β-D-glucan, α-L-fuco-2-(1,6)-D-galactan, and β-D-glucomannan. MP-PSC (200 μg/mL) increased the number of CD14+ monocyte cells in the blood, after ex vivo incubation for 24 h. It dose-dependently (50-200 μg/mL) activated the spontaneous oxidative burst of whole blood phagocytes, NO, and interleukin 6 productions in RAW264.7 cells. MP-PSC exhibited a low antioxidant activity and failed to suppress the oxidative burst and NO generation, induced by inflammatory agents. It (2.0%, w/v) stimulated probiotic co-cultures and hindered the growth and biofilm development of Escherichia coli, Streptococcus mutans and Salmonella enterica. MP PSs can be included in synbiotics to test their immunostimulating effects on compromised immune systems and gut health.

Barbero G. Exposure to Essential and Toxic Elements via Consumption of Agaricaceae, Amanitaceae, Boletaceae, and Russulaceae Mushrooms from Southern Spain and Northern Morocco

The demand and interest in mushrooms, both cultivated and wild, has increased among consumers in recent years due to a better understanding of the benefits of this food. However, the ability of wild edible mushrooms to accumulate essential and toxic elements is well documented. In this study, a total of eight metallic elements and metalloids (chromium (Cr), arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb), copper (Cu), zinc (Zn), and selenium (Se)) were determined by ICP-MS in five wild edible mushroom species (Agaricus silvicola, Amanita caesarea, Boletus aereus, Boletus edulis, and Russula cyanoxantha) collected in southern Spain and northern Morocco. Overall, Zn was found to be the predominant element among the studied species, followed by Cu and Se. The multivariate analysis suggested that considerable differences exist in the uptake of the essential and toxic elements determined, linked to species-intrinsic factors. Furthermore, the highest Estimated Daily Intake of Metals (EDIM) values obtained were observed for Zn. The Health Risk Index (HRI) assessment for all the mushroom species studied showed a Hg-related cause of concern due to the frequent consumption of around 300 g of fresh mushrooms per day during the mushrooming season.

Edible Mushrooms for Sustainable and Healthy Human Food: Nutritional and Medicinal Attributes

Global food production faces many challenges, including climate change, a water crisis, land degradation, and desertification. These challenges require research into non-traditional sources of human foods. Edible mushrooms are considered an important next-generation healthy food source. Edible mushrooms are rich in proteins, dietary fiber, vitamins, minerals, and other bioactive components (alkaloids, lactones, polysaccharides, polyphenolic compounds, sesquiterpenes, sterols, and terpenoids). Several bioactive ingredients can be extracted from edible mushrooms and incorporated into health-promoting supplements. It has been suggested that several human diseases can be treated with extracts from edible mushrooms, as these extracts have biological effects including anticancer, antidiabetic, antiviral, antioxidant, hepatoprotective, immune-potentiating, and hypo-cholesterolemic influences. The current study focuses on sustainable approaches for handling edible mushrooms and their secondary metabolites, including biofortification. Comparisons between edible and poisonous mushrooms, as well as the common species of edible mushrooms and their different bioactive ingredients, are crucial. Nutritional values and the health benefits of edible mushrooms, as well as different biomedical applications, have been also emphasized. Further research is needed to explore the economic sustainability of different medicinal mushroom bioactive compound extracts and their potential applications against emerging diseases such as COVID-19. New approaches such as nano-biofortification are also needed to supply edible mushrooms with essential nutrients and/or to increase their bioactive ingredients.