Agaricus crocodilinus (Agaricaceae), an edible saprotrophic mushroom, accumulates high concentrations of cadmium (Cd) in unpolluted environments. This study investigates whether this species has evolved mechanisms to store Cd complexed with metallothioneins (MTs), proteins that bind heavy metal ions via cysteinyl (Cys)-thiolate bonds, how these MTs originated, and how similar mechanisms are present in other fungal species. Size exclusion chromatography revealed that a substantial fraction of Cd in A. crocodilinus sporocarps was sequestered in a 3.4 kDa complex containing Cys-rich peptides. Screening a sporocarp cDNA expression library in a Cd-sensitive Saccharomyces cerevisiae strain identified two MT transcripts, AcMT1 and AcMT2, encoding 49-amino acid (AA) AcMT1 with 10 Cys and 32-AA AcMT2 with 7 Cys. The presence of AcMT2 in the 3.4 kDa Cd-peptide complex isolated from sporocarp was confirmed by mass spectrometry. In mycelial isolates exposed to heavy metals, AcMT1 was more strongly upregulated, while AcMT2 was more expressed under normal conditions. Sequence comparisons revealed that AcMT2 is closer to the ancestral gene, whereas AcMT1 is a more recent duplicate. Combined bioinformatic and functional evidence supports AcMT2 as a constitutively expressed MT involved in Cd binding in the sporocarp, while AcMT1, though more inducible in mycelia and more protective in yeast, appears to serve a transient detoxification role. Moreover, the gene duplication and domain rearrangement mechanism underlying this MT diversification was also identified in other Agaricales and Boletales species.

• Klíčová slova
• Agaricaceae, Gene duplication, Gene internal duplication, Heavy metals,
• Publikační typ
• časopisecké články MeSH

In the 21st century, nanomaterials play an increasingly important role in our lives with applications in many sectors, including agriculture, biomedicine, and biosensors. Over the last two decades, extensive research has been conducted to find ways to synthesise nanoparticles (NPs) via mediation with fungi or fungal extracts. Mycosynthesis can potentially be an energy-efficient, highly adjustable, environmentally benign alternative to conventional physico-chemical procedures. This review investigates the role of metal toxicity in fungi on cell growth and biochemical levels, and how their strategies of resistance, i.e., metal chelation, biomineral formation, biosorption, bioaccumulation, compartmentalisation, and efflux of metals from cells, contribute to the synthesis of metal-containing NPs used in different applications, e.g., biomedical, antimicrobial, catalytic, biosensing, and precision agriculture. The role of different synthesis conditions, including that of fungal biomolecules serving as nucleation centres or templates for NP synthesis, reducing agents, or capping agents in the synthesis process, is also discussed. The authors believe that future studies need to focus on the mechanism of NP synthesis, as well as on the influence of such conditions as pH, temperature, biomass, the concentration of the precursors, and volume of the fungal extracts on the efficiency of the mycosynthesis of NPs.

• Klíčová slova
• biomolecule, biosynthesis, fungus, green synthesis, metal oxide nanoparticle, metallic nanoparticle, nanomaterial,
• MeSH
• bioakumulace MeSH
• biologický transport MeSH
• katalýza MeSH
• kovové nanočástice * MeSH
• redukční činidla MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• redukční činidla MeSH

This article presents a bibliometric study of 200 European publications released between 2001 and 2016, about the contamination of mushrooms by selected elements. The analysis includes figures on the type of analyte, its concentration, the species of fungi, and its country of origin. In the literature review, 492 species of mushrooms (wild-growing and cultured) found in 26 European countries and their concentration of 74 associated elements were analysed. The papers, which dealt mainly with the heavy metal (Cd, Cu, Fe, Pb, and Zn) concentrations of mushrooms, primarily came from Turkey, Poland, Spain, and the Czech Republic. More than 50% of the publications provided data about edible mushrooms. The results of the bibliometric analysis showed that over the 16 years, European research on fungal contamination by selected analytes has not lessened in popularity and is ongoing. Many of the studies underlined the need to assess the risk to human health arising from the consumption of contaminated mushrooms taken from various habitats. These results were the effect of, among other things, the strong interest in studies carried out on edible species, in which concentrations of mainly heavy metals that are dangerous to health and are marked were indicated (Cd, Pb, and Hg).

• Klíčová slova
• Bibliometric analysis, Heavy metals, Mushrooms, Review,
• MeSH
• Agaricales * MeSH
• bibliometrie MeSH
• látky znečišťující půdu analýza   MeSH
• lidé MeSH
• monitorování životního prostředí MeSH
• těžké kovy analýza   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Geografické názvy
• Česká republika MeSH
• Evropa MeSH
• Polsko MeSH
• Španělsko MeSH
• Turecko MeSH
• Názvy látek
• látky znečišťující půdu MeSH
• těžké kovy MeSH

Homeostatic mechanisms preventing the toxicity of heavy metal ions in cells involve, among others, compartmentalization and binding with peptidaceous ligands, particularly the cysteinyl-rich metallothioneins (MTs). We have previously shown that in natural conditions Zn-overaccumulating ectomycorrhizal (EM) fungus Russula bresadolae stores nearly 40% of Zn bound with cysteinyl- and hystidyl-containing RaZBP peptides, which resemble MTs, while the detoxification of Zn and Cd in EM Hebeloma mesophaeum relies upon compartmentalization in small vesicles and vacuoles, respectively. Here, we examined the performance of RaZBP1 gene expressed in H. mesophaeum mycelium with respect to handling of Zn and Cd. Expression of RaZBP1 impaired growth of the mycelium on low-Zn medium by 60%, the growth was partly ameliorated upon the addition of Zn and remained considerable up to 2 mmol/L Zn, while the growth of the wild-type and control mycelia transformed with empty T-DNA was severely reduced in the presence of 0.5 mmol/L Zn; furthermore, RaZBP1 slightly added to Cd tolerance in the range of Cd concentrations of 0.625 to 8 μmol/L. Staining of Zn- or Cd-exposed hyphal cells with Zn- or Cd-specific fluorescent tracers did not indicate that the expression of RaZBP1 would redirect the flow of the metals away from their innate sinks. Size exclusion chromatography of extracted metal species revealed that the complexes corresponding to Zn/Cd-RaZBP1 are present only in minute levels. Considering that RaZBP1 inhibited growth at low Zn, and despite the benefit that it provided to H. mesophaeum in the presence of high Zn and moderate Cd, these data indicate that the binding of excess Zn and Cd with RaZBP1 is not a trait that would be outright transmitted to H. mesophaeum.

• MeSH
• Basidiomycota genetika   MeSH
• cytoplazmatické vezikuly metabolismus   MeSH
• fungální proteiny genetika   metabolismus   MeSH
• Hebeloma genetika   růst a vývoj   metabolismus   MeSH
• kadmium metabolismus   MeSH
• metalothionein genetika   metabolismus   MeSH
• mycelium genetika   růst a vývoj   metabolismus   MeSH
• mykorhiza genetika   MeSH
• rekombinantní proteiny genetika   metabolismus   MeSH
• zinek metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• fungální proteiny MeSH
• kadmium MeSH
• metalothionein MeSH
• rekombinantní proteiny MeSH
• zinek MeSH