Xerocomus Badius Research Articles

Activity of Scottish Plant, Lichen and Fungal Endophyte Extracts against Mycobacterium aurum and Mycobacterium tuberculosis

With tuberculosis the leading bacterial killer worldwide and other mycobacterial diseases on the increase, the search for new antimycobacterial agents is timely. In this study, extracts from plants, lichens and fungal endophytes of Scottish provenance were screened for activity against Mycobacterium aurum and M. tuberculosis H(37)Rv. The best activity against M. aurum was observed for extracts of Juniperus communis roots and Cladonia arbuscula (MIC = 4 microg/mL), and a fungal endophyte isolated from Vaccinium myrtillus (MIC = 8 microg/mL). The best activity against M. tuberculosis was observed for extracts of C. arbuscula, Empetrum nigrum, J. communis roots, Calluna vulgaris aerial parts, Myrica gale roots and stems (93 to 99% inhibition at 100 microg/mL). Potent antitubercular activity (90 to 96% inhibition at 100 microg/mL) was also observed for the ethanol extracts of Xerocomus badius, Chalciporus piperatus, Suillus luteus and of endophytes isolated from C. vulgaris, E. nigrum, Vaccinium vitis-idaea and V. myrtillus. The results obtained this study provide, in part, some scientific basis for the traditional use of some of the selected plants in the treatment of tuberculosis. They also indicate that fungal endophytes recovered from Scottish plants are a source of antimycobacterial agents worthy of further investigation.

Content of biogenic amines and polyamines in some species of European wild-growing edible mushrooms

The content of eight biologically active biogenic amines and polyamines were determined in fruiting bodies of 17 species of wild-growing edible mushrooms picked during 3 consecutive years. An analytical procedure, using freeze-dried samples, derivatisation with dansyl chloride and HPLC quantification had to be adapted in its extraction step due to the slimy character of the analysed mushrooms. No histamine and cadaverine were determined. Tyramine and tryptamine occurred at very low levels, usually up to 5 mg kg−1 fresh matter, whilst phenylethylamine contents varied widely from an undetectable level to 38 mg kg−1. Putrescine was the amine of the highest content, sometimes exceeding 150 mg kg−1 fresh matter, mainly in species of the family Boletaceae. The contents of spermidine were considerably higher than those of spermine, usually at levels of tens mg kg−1 fresh matter and sporadically above 100 mg kg−1. Thus, mushrooms are raw food materials with very high spermidine content. The highest spermidine levels occurred in spore-forming parts of fruiting bodies. In Xerocomus badius, statistically significant effects of the year of harvest, age and parts of the fruiting body and of their interactions on the contents of phenylethylamine, putrescine and spermidine were found.

Characterization of juvenile maritime pine (Pinus pinaster Ait.) ectomycorrhizal fungal community using morphotyping, direct sequencing and fruitbodies sampling

Using ectomycorrhizal root tip morphotyping (anatomical and morphological identification), molecular analysis (internal transcribed spacer region amplification and sequencing), and fruitbody sampling, we assessed diversity and composition of the ectomycorrhizal fungal community colonizing juvenile Pinus pinaster Ait. under natural conditions in NW Spain. Overall, we found 15 Basidiomycetes and two Ascomycetes. Members of the family Thelephoraceae represented up to 59.4% of the samples. The most frequent species was Tomentella sublilacina followed by Thelephora terrestris, Russula drimeia, Suillus bovinus, and Paxillus involutus, while the less frequent were Pseudotomentella tristis, Lactarius subdulcis, Russula ochroleuca, and Entoloma conferendum. From October 2007 to June 2008, we sampled 208 sporocarps belonging to seven genera and nine species: Thelephora terrestris, Paxillus involutus, Suillus bovinus, Xerocomus badius, Scleroderma verrucosum, Amanita gemmata, A. rubescens, Amanita sp., and Russula sp. The species belonging to the genus Amanita, X. badius and S. verrucosum were not found on root samples. By comparing our results with a bibliographic review of papers published from 1922 to 2006, we found five genera and six species which have not been previously reported in symbiosis with P. pinaster. This is the first time that the diversity of the ectomycorrhizal fungal community associated with P. pinaster was investigated using molecular techniques. Considering that only 38% of the genera found by sequencing were found as fruitbodies, we conclude that integrating morphotyping and sporocarps surveys with molecular analysis of ectomycorrhizas is important to documenting the ectomycorrhizal fungus community.

Isolation and quantitative determination of ergosterol peroxide in various edible mushroom species

Ergosterol peroxide, the steroidal derivative with cytotoxic activity, has been isolated for the first time from the mycelium of edible and medicinal mushroom Hericium erinaceum (lion’s mane mushroom) together with erinacine A. The new densitometric method was applied for the quantitative determination of ergosterol peroxide in n-hexane extracts of H. erinaceum, Laetiporus sulfureus (chicken mushroom) , and Morchella esculenta (common morel) mycelia, as well as in Boletus edulis (king bolete), Suillus bovinus (Jersey cow mushroom) , and B. badius (bay bolete) fruiting bodies. The ergosterol peroxide content reached 15.98 ± 0.78, 10.07 ± 0.75, 13.37 ± 0.56, 29.32 ± 1.43, 17.27 ± 0.84, and 12.60 ± 0.59 mg per 100 g, respectively. What is significant was that ergosterol peroxide was identified for the first time, to the best of our knowledge, in edible mushrooms mentioned above.

Ectomycorrhizal mycelial species composition in apatite amended and non-amended mesh bags buried in a phosphorus-poor spruce forest

We studied the effect of apatite amendment on ectomycorrhizal (EM) mycelial biomass production and species composition in a phosphorus-poor spruce forest using sand-filled mesh bags. Control and apatite-amended bags were buried in pairs in the lower part of the organic horizon for one growth season. DNA extraction, PCR of the ITS region, cloning and random sequencing were used to examine the fungal species composition in each bag. Sequences were identified by comparison with the UNITE database and GenBank. Our study confirmed previous results that the major fungal ingrowth in mesh bags was of EM origin. On average 13 species were detected in each bag. Tylospora fibrillosa, Amphinema sp., Tomentellopsis submollis, and Xerocomus badius made up almost 80 % of the EM sequences. High biomass was related to increased dominance of specific species. There were no statistically significant differences in biomass production estimated from PLFA 18:2ω6, 9, or between fungal communities of apatite-amended and control bags estimated from DNA after one growth season. The potential of the mesh bag method in studies of functional diversity of EM mycelia in the field is discussed.

Competition for nitrogen between Pinus sylvestris and ectomycorrhizal fungi generates potential for negative feedback under elevated CO2

We investigated fungal species-specific responses of ectomycorrhizal (ECM) Scots pine (Pinus sylvestris) seedlings on growth and nutrient acquisition together with mycelial development under ambient and elevated CO2. Each seedling was associated with one of the following ECM species: Hebeloma cylindrosporum, Laccaria bicolor, Suillus bovinus, S. luteus, Piloderma croceum, Paxillus involutus, Boletus badius, or non-mycorrhizal, under ambient, and elevated CO2 (350 or 700 μl l−1 CO2); each treatment contained six replicates. The trial lasted 156 days. During the final 28 days, the seedlings were labeled with 14CO2. We measured hyphal length, plant biomass, 14C allocation, and plant nitrogen and phosphorus concentration. Almost all parameters were significantly affected by fungal species and/or CO2. There were very few significant interactions. Elevated CO2 decreased shoot-to-root ratio, most strongly so in species with the largest extraradical mycelium. Under elevated CO2, ECM root growth increased significantly more than hyphal growth. Extraradical hyphal length was significantly negatively correlated with shoot biomass, shoot N content, and total plant N uptake. Root dry weight was significantly negatively correlated with root N and P concentration. Fungal sink strength for N strongly affected plant growth through N immobilization. Mycorrhizal fungal-induced progressive nitrogen limitation (PNL) has the potential to generate negative feedback with plant growth under elevated CO2.

Production of theanine by Xerocomus badius (mushroom) using submerged fermentation

Theanine is a rare amino acid mainly produced by the genus Camellia, which is also found in the Basidiomycete fungus (mushroom) Xerocomus badius. Besides its favorable taste, broad potential physiological effects have been reported in the recent years, leading to the very fast growing demand for theanine worldwide. Thus a series of methods to produce theanine have been developed, including tea callus cultivation, chemical synthesis, extraction from the fresh leaves of the tea plant, and enzymatic synthesis. Different from the previous procedures, we reported here a novel protocol to produce theanine from the mushroom X. badius by means of submerged fermentation. Moreover, response surface methodology (RSM) was employed to optimize various parameters during fermentation. The statistic results indicated that the maximum theanine yield of X. badius (17.2420 mg/L) could be achieved at the optimal conditions, with glucose of 29.17 g/L, yeast extract of 6.38 g/L in a broth volume of 61.43 mL (within a flask of 250 mL) at an initial pH at 5.63. These predicted values were also validated by experiments. Taken together, these findings provided us a promising strategy for the production of theanine from X. badius in addition to the traditional preparation processes.

Metal/metalloid contamination and isotopic composition of lead in edible mushrooms and forest soils originating from a smelting area

High metal contents in edible mushrooms growing in severely contaminated industrial areas pose an important toxicological risk. In the presented study, trace element (Pb, Cd, Zn, Cu, Ag, As, Se) contents were determined in caps and stipes of three different edible mushroom species ( Boletus edulis Bull. Fr., Xerocomus badius Fr. Gilb., Xerocomus chrysenteron Bull. Quél.). Additionally, information about the chemical fractionation of metals in separate soil horizons and Pb isotopic data from soils and fruiting bodies allowed a more detailed insight on the uptake mechanisms of metals by the studied mushroom species. Total metal and metalloid concentrations in the organic soil horizons reached 36 234 mg Pb kg − 1 ; 11.9 mg Cd kg − 1 ; 519 mg Zn kg − 1 ; 488 mg Cu kg − 1 ; 25.1 mg Ag kg − 1 ; 120 mg As kg − 1 and 5.88 Se mg kg − 1 . In order to evaluate the accumulation capacity of the studied species, bioconcentration factors (BCF) were calculated for separate trace elements. For selected metals (Pb, Cd, Zn, Cu), a modified BCF calculation (using EDTA-extractable concentrations of metals in soil) was proposed. High contents of Pb (up to 165 mg kg − 1 ) and Cd (up to 55 mg kg − 1 ) exceeded all the regulatory limits in all the studied species. This was also the case for Se (up to 57 mg kg − 1 ) in B. edulis. Intensive consumption of this species grown in such polluted areas can therefore pose toxicological risks for human health. A novel finding was that X. badius can act as an Ag accumulating species when grown at polluted sites due to the high concentrations of Ag (up to 190 mg kg − 1 ) in caps. Pb isotopic data showed that Pb originating from the recent air pollution control residues is present mainly in the exchangeable/acid-extractable fraction of the organic horizons and is taken up by fruiting bodies; especially in the case of B. edulis, where fast Pb accumulation occurs. Due to the high species-dependent variations of metal contents, the studied mushrooms are not suitable as bioindicators of environmental pollution.

Determination of antioxidant activity and antioxidant compounds in wild edible mushrooms

The methanolic extracts of dried Agaricus bisporus, Polyporus squamosus, Pleurotus ostreatus, Lepista nuda, Russula delica, Boletus badius, and Verpa conica were analyzed for antioxidant activity in different systems including reducing power, free radical scavenging, superoxide anion radical scavenging, total antioxidant activity, and metal chelating activities. Those various antioxidant activities were compared to standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and α-tocopherol. The percentage inhibition methanolic extracts of dried Russula delica, Boletus badius, Agaricus bisporus, Polyporus squamosus, Pleurotus ostreatus, Lepista nuda and Verpa conica at 100 μg/mL concentrations on peroxidation in linoleic acid system were 99.7%, 99.2%, 98.8%, 98.4%, 98.3%, 97.9% and 97.7%, respectively, and greater than those 400 μg/mL of α-tocopherol, BHA and BHT (77%, 85%, and 97%). Among methanolic extracts from seven wild edible mushrooms, the reducing power of Russula delica and Verpa conica were excellent, and were 1.32 and 1.22 at 200 μg/mL, respectively. Methanolic extract from Verpa conica, Boletus badius and Russula delica proved to be better at scavenging O 2 − than other mushroom species. The scavenging effects of methanolic extracts from mushroom species and standards on the DPPH radical decreased in the order of BHA> α-tocopherol> Lepista nuda> Russula delica> Polyporus squamosus> Pleurotus ostreatus> Agaricus bisporus> Verpa conica> Boletus badius and were, at the concentration of 180 μg/mL, 97.4, 95.4, 91.3, 86.1, 82.8, 81.3, 77.5, 75.7 and 68.7, respectively. The metal scavenging effect of extract of the mushroom species and standards decreased in the order of Verpa conica> Lepista nuda> Russula delica> Boletus badius> Polyporus squamosus>BHT> Pleurotus ostreatus> Agaricus bisporus>BHA> α-tocopherol. On the other hand, total phenolic compounds, α-tocopherol, and β-carotene were determined in the methanolic extracts of dried Agaricus bisporus, Polyporus squamosus, Pleurotus ostreatus, Lepista nuda, Russula delica, Boletus badius, and Verpa conica.

Fatty acid composition of various ectomycorrhizal fungi and ectomycorrhizas of Norway spruce

Whole cell fatty acid (WCFA) compositions of three different structures of ectomycorrhizal (ECM) fungi: sporocarps, pure culture mycelia and ectomycorrhizas were analysed to evaluate the potential use of fatty acid profiles as biomarkers for ECM fungi and ectomycorrhiza-associated bacteria. Sporocarps of Amanita muscaria, Amanita rubescens, Lactarius rufus, Lactarius thejogalus, Leccinum scabrum, Paxillus involutus, Russula foetens, Russula rosea, Russula vesca, Suillus grevillei, Tylopilus felleus, Xerocomus badius, Xerocomus subtomentosus, pure cultures of A. muscaria, P. involutus, X. badius, X. subtomentosus, Suillus bovinus Suillus luteus and seven ectomycorrhizal morphotypes of Norway spruce were examined. Our results revealed species-specific composition of fatty acids of fungal sporocarps and pure culture mycelia. Ectomycorrhizal morphotypes distinguished and identified by morphological and molecular methods (PCR-RLFP and sequencing) created specific fatty acid profiles. The dominating fatty acids in pure cultures and sporocarps were 18:2 ω6,9, 18:1 ω9 and 16:0, whereas ectomycorrhizas also contained plant and bacterial specific fatty acids. Especially, fatty acids specific to Gram-positive bacteria 15:0 anteiso and 17:0 anteiso were present in relatively high amounts and suggested that these bacteria are dominating in the examined Norway spruce mycorrhizosphere. In conclusion, our results show that fatty acid based methods can be useful in studies of ectomycorrhizal fungi, both as a quick method for differentiation of fungal species and also in studies of mycorrhiza-associated microorganisms in the field.

Radiocesium in mushrooms from selected locations in the Czech Republic and the Slovak Republic

In this paper, activity concentrations of radiocesium in mushrooms from various locations in the Czech Republic and the Slovak Republic in the years 2000-2004 are presented. Summary reports of Czech regulatory bodies have judged the average activity concentrations in mushrooms to be remarkably below the maximum permissible level of contamination. However, there are certain regions where radiocesium activities have approached the maximum permissible level for contamination of basic foodstuff. For example, the highest activity concentration of (137)Cs measured by gamma-spectrometry was 2,263 Bq kg(-1) (on a dry mass basis), in Xerocomus badius from Staré Ransko (a locality in the Czech-Moravian Highlands, Czech Republic). The highest activity concentration of (137)Cs measured in Slovakia was 966 Bq kg(-1) (on a dry mass basis), for Suillus luteus from Senica. For comparison, the corresponding activity concentration in a sample taken within the 30 km zone around Chernobyl was measured to be 6,000 Bq kg(-1) (on a dry mass basis). Our results have also demonstrated remarkably lower activity concentrations of (137)Cs in Slovakia compared to those in the Czech Republic.

Exponential drop of radiocesium activity in mushrooms due to the effect of acetic acid

The capability of vinegary pickle (2% solution of acetic acid) as a decontaminant for mushrooms has been studied. The complete sporocarps of Xerocomus badius, Suillus luteus and Lepista saeve in dry weight, the native state and after defrosting were investigated. The mushroom samples gathered in forest ecosystems were contaminated by the post-Chernobyl radiocesium. The activity concentrations of 137Cs were determined by the semiconductor gammaspectroscopy. It was proved that the reduction in activity has been affected by the frequency of replacement of acetic acid. However, the number of replacements is limited due to a change of the mushroom consistency. The vinegary pickle is already effective after the first treatment, i.e. the activity in the dry weight was reduced by 73%, and in the native state by 59%. The radiocesium activity follows an exponential curve with the exponents of 0.766 (the dry weight with the values exceeding the maximum permissible level of contamination), 0.266 (the dry weight with low activities) and 0.040 (mushrooms in the native state with the activities near the maximum permissible level of contamination) for the repeated effect of the fresh solution of acetic acid.

Oribatid mite (Acari, Oribatida) feeding on ectomycorrhizal fungi

The coexistence of a large number of soil animals without extensive niche differentiation is one of the great riddles in soil biology. The main aim of this study was to explore the importance of partitioning of food resources for the high diversity of micro-arthropods in soil. In addition, we investigated if ectomycorrhizal fungi are preferentially consumed compared to saprotrophic fungi. Until today, ectomycorrhizal fungi have never been tested as potential food resource for oribatid mites. We offered six ectomycorrhizal fungi [Amanita muscaria (L.) Hook., Boletus badius (Fr.) Fr., Cenococcum geophilum Fr., Laccaria laccata (Scop.) Fr., Paxillus involutus (Batsch) Fr. and Piloderma croceum J. Erikss. & Hjortstam], one ericoid mycorrhizal fungus [Hymenoscyphus ericae (D.J. Read) Korf & Kernan] and three saprotrophic fungi [Agrocybe gibberosa (Fr.) Fayod, Alternaria alternata (Fr.) Keissl. and Mortierella ramanniana (A. Møller) Linnem.] simultaneously to each of the mainly mycophagous oribatid mite species Carabodes femoralis (Nicolet), Nothrus silvestris Nicolet and Oribatula tibialis Nicolet. The ericoid mycorrhizal fungus H. ericae and the ectomycorrhizal fungus B. badius were preferentially consumed by each oribatid mite species. However, feeding preferences differed significantly between the three species, with O. tibialis being most selective. This study for the first time documented that oribatid mites feed on certain ectomycorrhizal fungi.

Study of Heavy Metals in Wild Edible Mushrooms under Different Pollution Conditions by X-Ray Fluorescence Spectrometry

In this work we studied and compared the metal uptake in edible mushrooms (Lepiota procera, Boletus badius, Boletus edulis, Tricholoma equestry, Lactarius deliciosus, Cantarelus tubalformis and Cantarelus edulis), relative to sampling sites submitted to different pollution conditions: car traffic, soil pollution due to pesticides and fertilizers used in old vineyards, and incineration of hospital waste. Soil was also collected in some places, and its content was correlated to the corresponding one in some mushrooms species. All samples, without any chemical treatment, were analyzed by an X-ray fluorescence set-up. This technique is based on a monochromatic X-ray beam ionizing the atoms of the sample. Following this ionization, the emitted radiation is characteristic of the element, allowing its identification and quantification. Vineyards are normally submitted to very high amounts of sulfating, containing high copper concentrations. This metal is accumulated on the soil, and can be up-taken by vegetation. Very high levels of Fe and Cu were found in Lepiota procera species in old vineyards. Zinc was found to be always higher than Cu by factors ranging from 1.5 to 8 in clean wood taken as a reference for the whole analyzed species, while in old vineyards the ratio Zn/Cu reach 0.25 for Lepiota procera. This is correlated to the soil content for both elements. In addition, pollution induced by car traffic was checked in some samples, collected in the proximity of highways. Pb was the main contaminant in these areas, and presenting values 10 times higher than the corresponding ones in sites not submitted to pollution, for some species. Mushrooms contamination due to incineration of hospital waste was also studied, but we did not observe any contamination involving heavy metals in the several analyzed species around these areas. This is in agreement with what was expected, taking into account that hospital waste is mostly organic and, in principle, no heavy metals would be observed.

Radionuclides content in Xerocomus badius and other commercial mushrooms from several regions of Poland

In this study the levels of 137Cs, mostly originating from the Chernobyl fallout, as well as levels of natural radionuclides 40K and 210Pb present in caps and stalks of edible mushroom samples and soil from Poland were measured. The analytical technique used was alpha spectrometry to determine 210Pb through its granddaughter 210Po. The 137Cs and 40K activity concentrations were determined by gamma spectrometry. The radionuclide activities in Xerocomus badius were in the ranges: 330–6670 ( 137Cs), 180–1520 ( 40K) and 0.70–32.0 ( 210Pb) Bq kg −1 d.w. The highest measured concentration of 137Cs was in the caps of X. badius from the Borecka Forest. The caps of examined mushrooms showed significantly higher activity concentrations compared to the stalks. In order to estimate the degree of accumulation of each element by mushrooms, transfer factor (TF) soil–cap and soil–stalk values were calculated. Also, some commercial mushrooms were examined such as dried, frozen and marinated products.

Radioactive Contamination of Ukrainian Mushrooms

Even 18 years after the Chernobyl catastrophe, radioactive contamination of wild growing mushrooms, in some cases reaching very high levels, created human health problems resulting from their nutritional and medicinal use. According to radioecological evaluations, the internal dose of irradiation in this case may reach 40−60%. A combination of macro- and micromycetes mycelial biomass and its capacity to uptake and retain radionuclides play very important roles in their migration and distribution. Actually, knowledge about the mechanisms involved in the accumulation and retention is incomplete. There is a positive correlation among the levels of soil contamination, degree of humidity, pH, rainfall, and radionuclide accumulation in mushrooms, although the species and ecological specificities of uptake are also observed. To measure species specificity of uptake, species-hyperaccumulators—for instance, radiocaesium—were used as bioindicators of contaminated soils. Among them, the widely spread and common species, Lactarius rufus (Scop.:Fr.) Fr. and Paxillus involutus (Batsch:Fr.) Fr., not consumed by the population because of their inedibility and toxicity, are now the most convenient test objects for long-term monitoring.During the last few years in about 80% of mushroom samples traditionally included in the Ukrainian diet—species of Boletaceae (Xerocomus spp., Suillus spp., Leccinum scabrum (Bull.:Fr.) S.F.Gray, Boletus edulis Bull.:Fr.) and Cantharellus cibarius (Fr.:Fr.) Fr. taken from areas with an average soil contamination of 0.1−5 Ci/km2 (presently, the collecting and consuming of wild growing mushrooms are practically not controlled)—the 137Cs levels exceeded permissible limits adopted in the Ukraine (2500 Bq/kg d.w.). Mushrooms growing in the Exclusion Zone, in the vicinity of the Chernobyl Power Plant (with 137Cs contamination density of 837 Ci/km2) accumulated up to millions of Bq/kg d.w. In 2004 137Cs activity in samples from the location of Novo-Shepelychi was within (in Bk/kg d.w.) 340,000 (Armillariella mellea (Vahl.:Fr.) P.Kumm.) to 20,000,000 (Xerocomus subtomentosus (L.:Fr.) Quél.), and 90Sr within 2000 (X. subtomentosus) to 13,000 (Stropharia aeruginosa (W.Curt.:Fr.) Quél.). Transfer factors for 137Cs were in X. subtomentosus 645, P. involutus 548, Lactarius turpis (Weinm.)Fr.280, L. deliciosus (L.:Fr.) S.F.Gray 222; for 90Sr Tf were in S. aeruginosa 6.0, L. turpis 5.1,A. mellea 3.1. The ratio of 137Cs/90Sr was within the range of 7.5−10,000. Mushrooms growing on the highly contaminated territories are permanently subjected to chronic irradiation. Taking into account polymorphism peculiar to mushrooms, the direct finding of morphose for them is difficult. Microstructural morphology of three bioindicative species using light and electron scanning microscopy was studied. It was statistically established that the spore length in Xerocomus badius (Fr.:Fr.) Kuhn. ex Gilb., Paxillus involutus, and Lactarius turpis samples collected in the Exclusion Zone was bigger than in the controls. In some cases, in the hymenophore of studied samples, parts with abnormally large as well as with very small spores were found. The observed variability indicated that high dosages resulting from radionuclides incorporated by mycelium and fruiting bodies from contaminated soils affect the hereditary structures of mushrooms.In nature mushrooms accumulate less 90Sr than 137Cs. In cultivation conditions, increasing levels of radiostrontium accumulation for Lentinus edodes (Berk.) Singer and Pleurotus ostreatus (Jacq.:Fr.)P. Kumm. (Grodzinskaya and Kuchma, 2004) were observed. This phenomenon can be connected to the higher biological availability of 90Sr from mixed and watered substrates. An increase of 90Sr activity in wood (observed in the last few years in contaminated territories) inevitably will cause an increase in its content in lignotroph species. Therefore, the selective control of 90Sr accumulation in cultivated lignotrophs, even in territories with low surface soil contamination, is strongly recommended.

Macro- and microelement contents in fruiting bodies of wild mushrooms from the Notecka forest in west-central Poland

Fruiting bodies of wild mushrooms and forest soil samples were collected and analyzed for macro- (N, P, K, S, Ca, Mg) and microelement (Al, Zn, Fe, Mn, Cd, Pb) contents in pine stands of the Notecka Forest in west-central Poland. Elements were determined by atomic absorption spectrometry in 160 samples of 8 fungal species and 15 underlying soil samples. Macro- and microelement contents in soil were low and characteristic of the poor and acidic sandy soils of the Polish lowlands not influenced by industrial pollution. In fruiting bodies, the highest mean concentration of macroelements (dry mass basis) was found for N (40.0 g kg −1), followed by K (33.0 g kg −1), P (5.4 g kg −1), S (2.2 g kg −1), Ca (1.0 g kg −1) and Mg (0.7 g kg −1). All macroelements (except for Ca) were concentrated in considerably higher levels in the fruiting bodies than in the forest soil. Nitrogen, P, K, S and Mg were preferably translocated into the cap rather than the stipes. Calcium, however, was often found in higher concentration in stipes than in caps. The mean microelement concentrations, across all tested fungi, were in the following order: Al > Zn > Fe > Mn > Pb > Cd. Microelements showed different distributions, depending on the part of the fruiting body. Some were more concentrated in the caps and some in stipes and distributions varied among species. Xerocomus badius is the most often harvested edible mushroom in the Notecka Forest. Pb and Cd distributions in fruiting bodies of this mushroom were evaluated in order to assess health risks to consumers. The estimated dietary exposures to Pb and Cd for consumers of this mushroom were in excess of guidelines on safe exposures.

Experimental study for increasing productivity of Boletus edulis s.l. in Italy

A drastic decrease in the presence and productivity of many fungal species, especially symbionts, has been recorded in various parts of Europe. Many of the most famous edible species, such as the group of Boletus edulis s.l., are in this category. The present study proposes to clarify the ecological requirements of these species ( B. edulis s.l.), in order to provide guidelines for environmental management aimed at conserving the ideal habitat of this culinary delicacy. The presence of B. edulis in two age classes (30 and 60 years) of fir woods and data on the effects of various management treatments (thinning and litter removal) on the fruiting process are reported. B. edulis is replaced by Boletus badius in older stands. Medium thinning seems to have a positive effect whereas removal of the litter layer has a negative effect on the fruiting process of B. edulis.

Optical purity of (R)-(−)-1-octen-3-ol in the aroma of various species of edible mushrooms

The characteristic enantiomeric ratio of 1-octen-3-ol in various species of edible mushrooms was the subject of the investigation. The microdistillation–extraction apparatus of Likens–Nickerson was used for aroma isolation. The volatiles were separated on the usual GC capillary column and on the chiral GC column connected to an HP-6890 gas chromatograph. The following species of cultivated mushrooms were analysed: Agaricus bisporus, Pleurotus ostreatus, Hericium erinaceum, Pholiota nameco and Lentinus edodes, and wild growing: Boletus edulis, Xerocomus badius and Macrolepiota procera. Despite significant differences in the concentrations of 1-octen-3-ol, the optical purity of (R)-(−)-1-octen-3-ol in all the species was very high, the highest in A. bisporus (over 98.5%), the lowest in X. badius (over 82.1%). Several mushroom-like flavouring substances and food products of mushroom-like aroma were also tested. In all of them the racemic ratio of 1-octen-3-ol was determined; this suggests that the origin of the flavours was not natural.

Metals bioaccumulation by bay bolete, Xerocomus badius, from selected sites in Poland

The concentrations of 14 elements (Pb, Cd, Ag, Cu, Mn, Cr, Co, Ni, Fe, Zn, Na, K, Ca, Mg) were determined in fruiting bodies of bay bolete, Xerocomus badius, and the underlying soil substratum collected from northern and north-eastern Poland. The total metals content was determined by flame atomic absorption spectrometry (AAS), using deuterium-background correction. The caps of the mushroom examined showed greater concentrations of some metals than the stalks, and the values of the cap to stalk ratio were similar despite different sampling sites. In order to estimate the degree of accumulation of each element by mushrooms, bioconcentration factor values (BCFs) were calculated. Significant correlation coefficients ( P<0.001, P<0.01 and P<0.05) were found between concentrations of metals in the caps, stalks of Xerocomus badius and the associated soil as a substratum. Cluster analysis (CA) and discriminant function analysis (DFA) were applied to the concentration data obtained. Some spatial differences in metal concentrations, especially concerning Pb were identified.