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The Marasmius oreades agglutinin (MOA) is the holotype of an emerging family of fungal chimerolectins and an active Ca2+/Mn2+-dependent protease, which exhibits a unique papain-like fold with special active site features. Here we investigated the functional significance of the structural elements differentiating MOA from other papain-like cysteine proteases. X-ray crystal structures of MOA co-crystallized with two synthetic substrates reveal cleaved peptides bound to the catalytic site, corresponding to the final products of the proteolytic reaction. Anomalous diffraction data on crystals grown in the presence of calcium and manganese, cadmium or zinc resolve the calcium/manganese preference of MOA and elucidate the inhibitory roles of zinc and cadmium towards papain-like cysteine proteases in general. The reported structures, together with activity data of MOA active site variants, point to a conservation of the general proteolysis mechanism established for papain. Ultimately, the findings suggest that papain and the papain-like domain of MOA are the product of convergent evolution., Graphical abstract Image 1, Highlights • MOA is a chimerolectin with protease activity carrying a unique papain-like fold. • The structures of inactive MOA variants reveal cleaved peptides in the active site. • Anomalous diffraction data elucidate activation or inhibition by different metals. • The MOA papain-like domain is a product of convergent evolution. • MOA is the holotype of an emerging family of enzymatically active fungal lectins.

The purpose of this paper was discovering the diversity of macromycetes in the territory of Batocina (Serbia). Field studies, which lasted more than a year, revealed the presence of 200 species of macromycetes. The identified species belong to phyla Basidiomycota (191 species) and Ascomycota (9 species). The biggest number of registered species (100 species) was from the order Agaricales. Among the identified species was one strictly protected - Phallus hadriani and seven protected species: Amanita caesarea, Marasmius oreades, Cantharellus cibarius, Craterellus cornucopiaodes, Tuber aestivum, Russula cyanoxantha and R. virescens; also, several rare and endangered species of Serbia. This paper is a contribution to the knowledge of the diversity of macromycetes not only in the territory of Batocina, but in Serbia, in general.

Marasmius oreades is a basidiomycete fungus that grows in so called “fairy rings,” which are circular, underground mycelia common in lawns across temperate areas of the world. Fairy rings can be thought of as natural, long-term evolutionary experiments. As each ring has a common origin and expands radially outwards over many years, different sectors will independently accumulate mutations during growth. The genotype can be followed to the next generation, as mushrooms producing the sexual spores are formed seasonally at the edge of the ring. Here, we present new genomic data from 95 single-spore isolates of the species, which we used to construct a genetic linkage map and an updated version of the genome assembly. The 44-Mb assembly was anchored to 11 linkage groups, producing chromosome-length scaffolds. Gene annotation revealed 13,891 genes, 55% of which contained a pfam domain. The repetitive fraction of the genome was 22%, and dominated by retrotransposons and DNA elements of the KDZ and Plavaka groups. The level of assembly contiguity we present is so far rare in mushroom-forming fungi, and we expect studies of genomics, transposons, phylogenetics, and evolution to be facilitated by the data we present here of the iconic fairy-ring mushroom.

Fairy rings caused by Marasmius oreades Fr. and other fungi cause considerable damage to turfgrasses. The recommended control measures for this disease are either soil fumigation or digging up the affected turf and replacing it with noninfested soilo Both methods require subsequent reseeding or resodding of the area. Results of two years' experimentation indicate that chemical control of fairy ring disease is not practical at the present. Hence, the possibilities of biological control were explored. This investigation has shown that Pythium artotrogus and other Pythium species will inhibit the mycelial growth of H· oreades and Agaricus bisporus. Fythium artotrogus was more antagonistic to A· bisporus than was other Pythium species tested. Pythium ultimum and an isolate of ~· irregulare were more antagonistic to M· oreades than was ~· artotrogus. Inhibition of H· oreades mycelium was shown to be due to toxic metabolites of~· artotrogus which diffuse through an agar gel. Fresh culture filtrates of P. artotrogus completely inhibited the growth of the agaric hyphal tips within twenty minutes. The biological activity of the filtrate was not reduced when kept at 7° C for prolonged periods, but it was shown to be thermolabile. Studies on the effect of temperature on mycelial growth showed that M· oreades and P. artotrogus had the same minimum temperature requirement. The optimum temperature for growth ii. was about 27° C for both fungi. Growth of l • artotrogus occurred at higher temperatures than M. oreades . At all temperatures i · artotrogus had a growth rate of two to ten times t hat of M· oreades. Marasmius oreades grew over a pH range of about 3 . 0 to 7.5 with an optimum of about 5.5 . Growth of l• artotrogus occurred from pH 2.5 to above 7 . 7 with an optimum at 5. 5. Pythium artotrogus was not parasitic to ! · bisporus or H· oreades. However, this Pythium species was shown to parasi tize the hyphae of l • aphanidermatum, P . debaryanum, P . irregulare, ~· splendens and l · ultimum. When encountering susceptible hyphae, the hyphal tip of P. artotrogus coiled around the host hypha followed by the formation of an appressorium on the hyphal surface of the host . Following penetration, t he infection hypha grew lengthwise in that of the host, degenerat i ng the cellular contents as it advanced. Although not parasitic, the hyphae of l · artotrogus formed coils around t he hyphae of i • arrhenomanes . Pythium artotrogus did not form coils and was not parasitic in its own or in the hyphae of i · graminicolum. Of the many Pythium species that were shown to be antagonistic to ! · bisporus and M· oreades , only P. artotrogus was shown to cause no injury to four species of Agrostis in laboratory pathogenicity tests. The data indicate that P. artotrogus has the potential to be used as a biological control agent for fairy ring caused by M· oreades. However, since it was shown that

Despite increasing knowledge on host-associated microbiomes, little is known about mechanisms underlying fungus-microbiome interactions. This study aimed to examine the relative importance of host genetic, geographic and environmental variations in structuring fungus-associated microbiomes. We analyzed the taxonomic composition and function of microbiomes inhabiting fungal fruiting-bodies in relation to host genetic variation, soil pH and geographic distance between samples. For this, we sequenced the metagenomes of 40 fruiting-bodies collected from six fairy rings (i.e., genets) of a saprotrophic fungus Marasmius oreades. Our analyses revealed that fine genetic variations between host fungi could strongly affect their associated microbiome, explaining, respectively, 25% and 37% of the variation in microbiome structure and function, whereas geographic distance and soil pH remained of secondary importance. These results, together with the smaller genome size of fungi compared to other eukaryotes, suggest that fruiting-bodies are suitable for further genome-centric studies on host-microbiome interactions.

This study is based on the phenolic composition and the antioxidant, anticancer, antimicrobial, and antibiofilm activities of the edible mushroom Marasmius oreades from Turkey. The phenolic composition of an M. oreades ethanol extract was measured by using the Folin-Ciocalteu method, aluminium chloride colorimetry, and ultraperformance liquid chromatography. The antioxidant activity was evaluated on the basis of DPPH radical scavenging activity. The effect of the M. oreades ethanol extract was also screened in order to determine glutathione-S-transferase, glutathione peroxidase, catalase, and superoxide dismutase enzyme activities. The antimicrobial activity of the mushroom extract was evaluated by using well diffusion and was based on the minimum inhibitory concentration. In addition, the antibiofilm potential of M. oreades was analyzed against Gram-positive and -negative bacteria. Finally, the anticancer effects of the mushroom extract were tested on colon (HT-29) and breast (MCF-7 and MDA-MB-231) cancer cell lines by using the MTT assay. The results revealed that the total amount of phenolics in the ethanol extract of M. oreades was 10.990 ± 0.0007 mg gallic acid equivalent/100 g, and the total amount of flavonoids was 1.139 ± 0.0052 mg quercetin equivalent/100 g. The ultraperformance liquid chromatography results indicated that the M. oreades ethanol extract contained various phenolic compounds: catechin, ferulic, gallic acid, and vanillic acid. The M. oreades ethanol extract scavenged about 80% of DPPH free radicals. It did not show any effect on the glutathione-S-transferase, glutathione peroxidase, and catalase enzyme activities, but its maximal concentration (10 mg/mL) increased superoxide dismutase activity (8%). The ethanol extract of M. oreades showed a moderate anticancer effect on the HT-29, MCF-7, and MDA-MB-231 cell lines. Although the ethanolic extract of the mushroom did not show sufficient antibacterial activity, it presented a strong antibiofilm effect against all studied pathogenic strains at the tested concentrations.

Summary Most mutations in coding regions of the genome are deleterious, causing selection to favor mechanisms that minimize the mutational load over time [ 1 , 2 , 3 , 4 , 5 ]. DNA replication during cell division is a major source of new mutations. It is therefore important to limit the number of cell divisions between generations, particularly for large and long-lived organisms [ 6 , 7 , 8 , 9 ]. The germline cells of animals and the slowly dividing cells in plant meristems are adaptations to control the number of mutations that accumulate over generations [ 9 , 10 , 11 ]. Fungi lack a separated germline while harboring species with very large and long-lived individuals that appear to maintain highly stable genomes within their mycelia [ 8 , 12 , 13 ]. Here, we studied genomic mutation accumulation in the fairy-ring mushroom Marasmius oreades. We generated a chromosome-level genome assembly using a combination of cutting-edge DNA sequencing technologies and re-sequenced 40 samples originating from six individuals of this fungus. The low number of mutations recovered in the sequencing data suggests the presence of an unknown mechanism that works to maintain extraordinary genome integrity over vegetative growth in M. oreades. The highly structured growth pattern of M. oreades allowed us to estimate the number of cell divisions leading up to each sample [ 14 , 15 ], and from this data, we infer an incredibly low per mitosis mutation rate (3.8 × 10−12 mutations per site and cell division) as one of several possible explanations for the low number of identified mutations.

Mushrooms can accumulate toxic trace elements. The objectives of the present study are to evaluate levels of mercury, cadmium, lead, and arsenic in dried mushrooms, to determine the effect of cooking on the contents of these elements, and to evaluate their bioaccessibility in the mushrooms ready for consumption. The results showed that Hg levels in Amanita ponderosa, Boletus edulis, Marasmius oreades, and Tricholoma georgii, as well as Cd levels in some samples of Amanita caesarea and T. georgii, exceeded the legislated limits. Cooking significantly reduced the levels of As (26–72%), whereas the reduction in levels of Hg, Cd, and Pb was much lower. However, the bioaccessibility of As (63–81%) was higher than the values obtained for the metals (, This work was supported by the Spanish Ministry of Economy and Competitiveness (AGL2015-68920-R), for which the authors are deeply indebted. Gabriela de Matuoka e Chiocchetti received a fellowship from the Brazilian Government (CAPES-proceso BEX1086/14-6) and Carlos Jadán-Piedra received a Personnel Training Grant from SENESCYT (Ecuadorian Ministry of Higher Education, Science, Technology and Innovation).

Background Fruiting body lectins have been proposed to act as effector proteins in the defense of fungi against parasites and predators. The Marasmius oreades agglutinin (MOA) is a lectin from the fairy ring mushroom with specificity for Galα1-3Gal containing carbohydrates. This lectin is composed of an N-terminal carbohydrate-binding domain and a C-terminal dimerization domain. The dimerization domain of MOA shows in addition calcium-dependent cysteine protease activity, similar to the calpain family. Methods Cell detachment assay, cell viability assay, immunofluorescence, live cell imaging and Western blot using MDCKII cell line. Results In this study, we demonstrate in MDCKII cells that after internalization, MOA protease activity induces profound physiological cellular responses, like cytoskeleton rearrangement, cell detachment and cell death. These changes are preceded by a decrease in FAK phosphorylation and an internalization and degradation of β1-integrin, consistent with a disruption of integrin-dependent cell adhesion signaling. Once internalized, MOA accumulates in late endosomal compartments. Conclusion Our results suggest a possible toxic mechanism of MOA, which consists of disturbing the cell adhesion and the cell viability. General significance After being ingested by a predator, MOA might exert a protective role by diminishing host cell integrity., Biochimica et Biophysica Acta (BBA) - General Subjects, 1860 (2), ISSN:0304-4165, ISSN:1872-8006

Plastic waste in the environment is a significant threat due to its resistance to biological processes. Here we report the ability of fungal strains found on floating plastic debris to degrade plastics. In particular, we wanted to know which fungi grow on plastic debris floating in the shoreline, whether these fungi have the ability to degrade plastics, whether the plastic-degrading fungi can degrade other complex C-polymers such as lignin, and whether lignin-degraders vice versa can also break down plastics. Overall, more than a hundred fungal strains were isolated from plastic debris of the shoreline of Lake Zurich, Switzerland, and grouped morphologically. Representative strains of these groups were then selected and genetically identified, altogether twelve different fungal species and one species of Oomycota. The list of fungi included commonly occurring saprotrophic fungi but also some plant pathogens. These fungal strains were then used to test the ability to degrade polyethylene and polyurethane. The tests showed that none of the strains were able to degrade polyethylene. However, four strains were able to degrade polyurethane, the three litter-saprotrophic fungi Cladosporium cladosporioides, Xepiculopsis graminea, and Penicillium griseofulvum and the plant pathogen Leptosphaeria sp. A series of additional fungi with an origin other than from plastic debris were tested as well. Here, only the two litter-saprotrophic fungi Agaricus bisporus and Marasmius oreades showed the capability to degrade polyurethane. In contrast, wood-saprotrophic fungi and ectomycorrhizal fungi were unable to degrade polyurethane. Overall, it seems that in majority only a few litter-saprotrophic fungi, which possess a wide variety of enzymes, have the ability to degrade polyurethane. None of the fungi tested was able to degrade polyethylene.

Eritadenine is a hypocholesterolemic compound that is found in several mushroom species such as Lentinula edodes, Marasmius oreades, and Amanita caesarea (1.4, 0.7 and 0.6 mg per g dry weight, respectively). It was synthesized during all developmental stages, being present in higher concentrations in the skin of shiitake fruiting bodies. When subjected to traditional cooking, grilling followed by frying were more adequate methodologies than boiling or microwaving to maintain its levels. Modern culinary processes such as texturization (with agar-agar) and spherification (with alginate) also interfered with its release. Grilling and gelling using gelatin enhanced eritadenine's bioaccessibility in an in vitro digestion model. An animal model (where male and female rats were administered 21 and 10 mg per kg animal per day of eritadenine) indicated that intake of the compound was safe under these concentrations; it reached the liver and reduced the atherogenic index (TC/HDL) in rat sera. Thus, it might be used to design a functional food., This research was supported by a national R&D program from the Spanish Ministry of Science and Innovation (project AGL2014-56211-R) and a regional program from the Community of Madrid, Spain (S2013/ABI-2728).

The contamination level of 92 samples (12 species) of wild edible mushrooms and underlying substrates with heavy metals (Cd, Cu, Hg, Pb and Zn) in the Slovak Paradise National Park that borders with a region of historical mining and processing of polymetallic ores, were determined. The collected samples were analyzed using of atomic absorption spectrophotometry. The metals were determined separately in hymenophore (H) and rest of fruit bodies (RFB). Bioaccumulation factor as well as ratio of metal content in H and RFB were calculated. Cadmium and lead contents in hymenophore exceeded statutory limits of the EU (Cd: 0.5 mg/kg dry weight (dw), Pb: 1.0 mg/kg dw) for edible mushrooms in 96% and 83% of the samples, respectively. The risk from the consumption of the collected mushroom species was calculated based on the provisionally tolerable weekly intake (PTWI) values, and the highest health risk arising with consumption of particularly Macrolepiota procera, Marasmius oreades and Russula vesca from the observed area was demonstrated. It was shown that average weekly consumption of tested mushrooms species results the threat of exceeding of PTWI limits in the case of cadmium values (by 164%, 86% and 4% of PTWI for M. oreades, R. vesca and R. puellaris, respectively) and of mercury (by 96% of PTWI for M. procera) but not lead.

The elemental composition of four wild edible mushroom species was determined by inductively coupled plasma optical emission spectrometry (ICP OES): scotch bonnet (Marasmius oreades), chanterelle (Cantarellus cibarius), porcini (Boletus edulis), and peppery milk-cap (Lactarius piperatus). Mushrooms are a potassium-rich food, which was confirmed in this study. M. oreades contained the highest concentration of almost all elements, except for cadmium, potassium, phosphorus, and lead. Lead and cadmium were present but at concentrations that are not hazardous to human health. A principal component analysis loading plot for elemental composition demonstrated that 95.51 percent of the total variance was present in the first two principal components. Cluster analysis separated the elements into three statistical significant clusters.

In vitro antioxidant and anti-inflammatory activities of fluidized bed ethanol extracts of Pleurotus ostreatus PQMZ91109, PBS281009, M2191 (obtained from a laboratory greenhouse), Agaricus bisporus, Marasmius oreades, Craterellus cornucopioides, and Tuber melanosporum were investigated using free radical scavenging activities, metal chelating effects, inhibition of lipid peroxidation (inhibition of peroxyl radicals), xanthine oxidase, and lipoxygenase, and identification of antioxidant compounds. Levels of different compounds with antioxidant properties demonstrated the presence of more tocopherols than polyphenol carboxylic acids and flavones. HPLC showed that T. melanosporum extracts had high correlation values between levels of different active compounds and antioxidant assay results. Tocopherol levels were highly correlated (R 2=0.867) with anti-inflammatory activities and inhibition of lipid peroxidation. Fluidized bed ethanol extracts from dried mushroom fruit bodies can be a source of products rich in tocopherols, and can constitute an important ingredient in food supplements.

Fungal Genetics Mutation can often occur as part of the process of cellular division and may have deleterious consequences for multicellular organisms. Through genomic sequencing of Marasmius oreades , a species of fairy ring mushroom, Hiltunen et al. found that in this relatively long-lived species, the accumulation of mutations is an order of magnitude less than previously discovered for any organism. This could not be attributed to purifying selection and indicates that this species has evolved high-fidelity replication and/or repair mechanisms to prevent mutation accumulation. Given that fungi, unlike mammals, do not sequester their reproductive germ cells, this is of interest in understanding how an organism can police its own cell division to maintain a low rate of mutation accumulation. Curr. Biol. 29 , 2758 (2019).

Papain-like cysteine proteases (PLCPs) constitute the largest group of thiol-based protein degrading enzymes and are characterized by a highly conserved fold. They are found in bacteria, viruses, plants and animals and involved in a number of physiological and pathological processes, parasitic infections and host defense, making them interesting targets for drug design. The Marasmius oreades agglutinin (MOA) is a blood group B-specific fungal chimerolectin with calcium-dependent proteolytic activity. The proteolytic domain of MOA presents a unique structural arrangement, yet mimicking the main structural elements in known PLCPs. Here we present the X-ray crystal structure of MOA in complex with Z-VAD-fmk, an irreversible caspase inhibitor known to cross-react with PLCPs. The structural data allow modeling of the substrate binding geometry and mapping of the fundamental enzyme-substrate interactions. The new information consolidates MOA as a new, yet strongly atypical member of the papain superfamily. The reported complex is the first published structure of a PLCP in complex with the well characterized caspase inhibitor Z-VAD-fmk.

A new mannose-recognizing lectin (MOL) was purified on an asialofetuin-column from fruiting bodies of Marasmius oreades grown in Japan. The lectin (MOA) from the fruiting bodies of the same fungi is well known to be a ribosome-inactivating type lectin that recognizes blood-group B sugar. However, in our preliminary investigation, MOA was not found in Japanese fruiting bodies of M. oreades, and instead, MOL was isolated. Gel filtration showed MOL is a homodimer noncovalently associated with two subunits of 13 kDa. The N-terminal sequence of MOL was blocked. The sequence of MOL was determined by cloning from cDNA and by protein sequencing of enzyme-digested peptides. The sequence shows mannose-binding motifs of bulb-type mannose-binding lectins from plants, and similarity to the sequences. Analyses of sugar-binding specificity by hemagglutination inhibition revealed the preference of MOL toward mannose and thyroglobulin, but asialofetuin was the strongest inhibitor of glycoproteins tested. Furthermore, glycan-array analysis showed that the specificity pattern of MOL was different from those of typical mannose-specific lectins. MOL preferred complex-type N-glycans rather than high-mannose N-glycans.

The Marasmius oreades mushroom lectin (MOA) is well known for its exquisite binding specificity for blood group B antigens. In addition to its N-terminal carbohydrate-binding domain, MOA possesses a C-terminal domain with unknown function, which structurally resembles hydrolytic enzymes. Here we show that MOA indeed has catalytic activity. It is a calcium-dependent cysteine protease resembling papain-like cysteine proteases, with Cys215 being the catalytic nucleophile. The possible importance of MOA's proteolytic activity for mushroom defense against pathogens is discussed.

Nitric oxide (NO) is a gaseous, radical molecule that plays a role in various physiological processes. Previously, we reported that transduction of murine colon cancer cells (MC38) with herpes simplex virus thymidine kinase (HSV-tk) gene resulted in a significant over-expression of cyclooxygenase-2 (COX-2) and activation of NF-kB pathway. In this study we show that TNFα, but not LPS, was significantly able to stimulate the production of NO in HSV-tk transduced 9L glioblastoma cell lines, mediated by the up-regulation of iNOS transcript and iNOS protein. The TNFα-induced up-regulation of iNOS expression was mediated by MAPK and NF-κB signaling pathways as revealed by using selective pharmaceutical inhibitors. A culture liquid extract of the edible and medicinal mushroom Marasmius oreades that was previously shown to inhibit iNOS expression in MCF-7 was utilized to prepare fractions and evaluate their ability to affect TNFα-induced iNOS expression in HSV tk transduced 9L cell lines. While most of the tested fractions were shown to inhibit TNFα-induced iNOS expression, they targeted different signaling pathways in a selective fashion. Here, we report that fraction SiSiF1 interfered with IKBα phosphorylation and consequently interfered with NF-κB activation pathway. SiSiF1 showed minimal interference with the phosphorylation of p38 and JNK proteins. In contrast, fraction SiSiF3 selectively inhibited the phosphorylation of p38 and fractions SiSiF4 and SiSiF5 selectively inhibited the phosphorylation of JNK with no observed effect against IKBα and p38 phosphorylation. Our data illustrate the complexity of iNOS regulation in HSV tk transduced 9L cell lines and also the richness of natural products with bioactive substances that may act synergistically through different signaling pathways to affect iNOS gene expression.

BACKGROUND: Macrolide polyene antibiotics possess potent broad-spectrum antifungal properties. Use of these agents in the field or in controlled environments is impeded by their poor water solubility and susceptibility to oxidation- and/or light-induced degradation. While typically used for human disease therapy, there is potential to expand the utility of polyene macrolide antibiotics, such as amphotericin B, for control of fungal disease infestation in agricultural settings. Thus, the susceptibility of this antibiotic to exposure-induced activity loss was evaluated. RESULTS: Incubation of the prototype polyene amphotericin B (AMB) with phospholipid vesicles and apolipoprotein A-I results in the formation of nanoscale complexes, termed nanodisks (NDs), capable of solubilizing significant quantities of AMB. To evaluate whether AMB incorporation into NDs conferred protection against light- or oxidation-induced damage, yeast growth inhibition assays were conducted. Compared with AMB solubilized in detergent micelles, AMB incorporated into NDs was protected from damage caused by exposure to UV light as well as by KMnO4-induced oxidation. Furthermore, AMB-NDs inhibited growth of the turfgrass fungus Marasmius oreades Fr. CONCLUSION: Results suggest that this water-soluble formulation of a natural, biodegradable, antifungal agent represents a potential cost-effective, non-toxic and environmentally friendly substitute for chemical agents currently employed to control a range of fungal infestations. Copyright © 2009 Society of Chemical Industry

Fructification organs of Calvatia excipuliformis, Lycoperdon perlatum, Laccaria amethystea, Armillaria mellea, Marosmius oreades, Xerula radicata, Cantharellus cibarius, Craterellus cornucopioides, Cantharellus tubaeformis, Hypholoma fasciculare, Clitocybe gibba, Collybia dryophila, Lepista nuda and Mycena aetites were collected from different localities in Black sea region of Turkey. Their trace metals concentrations were determined by atomic absorption spectrometry after wet and microwave digestion. The results were (as mg/kg) 150-1741 for iron, 15.5-73.8 for copper, 28.6-145 for manganese, 43.5-205 for zinc, 4.8-42.7 for aluminium and 0.9-2.6 for lead. The levels of lead analyzed in some edible mushroom samples were found to be higher than legal limits. The relative standard deviations (R.S.D.) were found below 10%. The accuracy of procedure was confirmed by certified reference material. (C) 2008 Elsevier B.V. All rights reserved.

Background Lectins are carbohydrate-binding proteins that are involved in fundamental intra- and extracellular biological processes. They occur ubiquitously in nature and are especially abundant in plants and fungi. It has been well established that certain higher fungi produce lectins in their fruiting bodies and/or sclerotia as a part of their natural resistance against free-living fungivorous nematodes and other pests. Despite relatively high diversity of the glycan structures in nature, many of the glycans targeted by fungal lectins are conserved among organisms of the same taxon and sometimes even among different taxa. Such conservation of glycans between free-living and parasitic nematodes is providing us with a useful tool for discovery of novel chemotherapeutic and vaccine targets. In our study, a subset of fungal lectins emanating from toxicity screens on Caenorhabditis elegans was tested for their potential to inhibit larval development of Haemonchus contortus. Methods The effect of Coprinopsis cinerea lectins - CCL2, CGL2, CGL3; Aleuria aurantia lectin – AAL; Marasmius oreades agglutinin - MOA; and Laccaria bicolor lectin – Lb-Tec2, on cultivated Haemonchus contortus larval stages was investigated using a larval development test (LDT). To validate the results of the toxicity assay and determine lectin binding capacity to the nematode digestive tract, biotinylated versions of lectins were fed to pre-infective larval stages of H. contortus and visualized by fluorescent microscopy. Lectin histochemistry on fixed adult worms was performed to investigate the presence and localisation of lectin binding sites in the disease-relevant developmental stage. Results Using an improved larval development test we found that four of the six tested lectins: AAL, CCL2, MOA and CGL2, exhibited a dose-dependent toxicity in LDT, as measured by the number of larvae developing to the L3 stage. In the case of AAL, CGL2 and MOA lectin, doses as low as 5 μg/ml caused >95 % inhibition of larval development while 40 μg/ml were needed to achieve the same inhibition by CCL2 lectin. MOA was the only lectin tested that caused larval death while other toxic lectins had larvistatic effect manifesting as L1 growth arrest. Using lectin histochemistry we demonstrate that of all lectins tested, only the four toxic ones displayed binding to the larvae’s gut and likewise were found to interact with glycans localized to the gastrodermal tissue of adults. Conclusion The results of our study suggest a correlation between the presence of target glycans of lectins in the digestive tract and the lectin-mediated toxicity in Haemonchus contortus. We demonstrate that binding to the structurally conserved glycan structures found in H. contortus gastrodermal tissue by the set of fungal lectins has detrimental effect on larval development. Some of these glycan structures might represent antigens which are not exposed to the host immune system (hidden antigens) and thus have a potential for vaccine or drug development. Nematotoxic fungal lectins prove to be a useful tool to identify such targets in parasitic nematodes., Parasites & Vectors, 8 (1), ISSN:1756-3305