Showing papers on "Mycelium published in 2017"

Advanced Materials From Fungal Mycelium: Fabrication and Tuning of Physical Properties.

Abstract: In this work is presented a new category of self-growing, fibrous, natural composite materials with controlled physical properties that can be produced in large quantities and over wide areas, based on mycelium, the main body of fungi. Mycelia from two types of edible, medicinal fungi, Ganoderma lucidum and Pleurotus ostreatus, have been carefully cultivated, being fed by two bio-substrates: cellulose and cellulose/potato-dextrose, the second being easier to digest by mycelium due to presence of simple sugars in its composition. After specific growing times the mycelia have been processed in order to cease their growth. Depending on their feeding substrate, the final fibrous structures showed different relative concentrations in polysaccharides, lipids, proteins and chitin. Such differences are reflected as alterations in morphology and mechanical properties. The materials grown on cellulose contained more chitin and showed higher Young's modulus and lower elongation than those grown on dextrose-containing substrates, indicating that the mycelium materials get stiffer when their feeding substrate is harder to digest. All the developed fibrous materials were hydrophobic with water contact angles higher than 120°. The possibility of tailoring mycelium materials' properties by properly choosing their nutrient substrates paves the way for their use in various scale applications.

Morphology and mechanics of fungal mycelium.

Abstract: We study a unique biomaterial developed from fungal mycelium, the vegetative part and the root structure of fungi. Mycelium has a filamentous network structure with mechanics largely controlled by filament elasticity and branching, and network density. We report the morphological and mechanical characterization of mycelium through an integrated experimental and computational approach. The monotonic mechanical behavior of the mycelium is non-linear both in tension and compression. The material exhibits considerable strain hardening before rupture under tension, it mimics the open cell foam behavior under compression and exhibits hysteresis and the Mullins effect when subjected to cyclic loading. Based on our morphological characterization and experimental observations, we develop and validate a multiscale fiber network-based model for the mycelium which reproduces the tensile and compressive behavior of the material.

Facilitation of phosphorus uptake in maize plants by mycorrhizosphere bacteria

Abstract: A major challenge for agriculture is to provide sufficient plant nutrients such as phosphorus (P) to meet the global food demand. The sufficiency of P is a concern because of it’s essential role in plant growth, the finite availability of P-rock for fertilizer production and the poor plant availability of soil P. This study investigated whether biofertilizers and bioenhancers, such as arbuscular mycorrhizal fungi (AMF) and their associated bacteria could enhance growth and P uptake in maize. Plants were grown with or without mycorrhizas in compartmented pots with radioactive P tracers and were inoculated with each of 10 selected bacteria isolated from AMF spores. Root colonization by AMF produced large plant growth responses, while seven bacterial strains further facilitated root growth and P uptake by promoting the development of AMF extraradical mycelium. Among the tested strains, Streptomyces sp. W94 produced the largest increases in uptake and translocation of 33P, while Streptomyces sp. W77 highly enhanced hyphal length specific uptake of 33P. The positive relationship between AMF-mediated P absorption and shoot P content was significantly influenced by the bacteria inoculants and such results emphasize the potential importance of managing both AMF and their microbiota for improving P acquisition by crops.

Mycelium-mediated transfer of water and nutrients stimulates bacterial activity in dry and oligotrophic environments

Abstract: Fungal-bacterial interactions are highly diverse and contribute to many ecosystem processes. Their emergence under common environmental stress scenarios however, remains elusive. Here we use a synthetic microbial ecosystem based on the germination of Bacillus subtilis spores to examine whether fungal and fungal-like (oomycete) mycelia reduce bacterial water and nutrient stress in an otherwise dry and nutrient-poor microhabitat. We find that the presence of mycelia enables the germination and subsequent growth of bacterial spores near the hyphae. Using a combination of time of flight- and nanoscale secondary ion mass spectrometry (ToF- and nanoSIMS) coupled with stable isotope labelling, we link spore germination to hyphal transfer of water, carbon and nitrogen. Our study provides direct experimental evidence for the stimulation of bacterial activity by mycelial supply of scarce resources in dry and nutrient-free environments. We propose that mycelia may stimulate bacterial activity and thus contribute to sustaining ecosystem functioning in stressed habitats.

Protective effect of three brown seaweed extracts against fungal and bacterial diseases of tomato

Abstract: The effect of extracts of the brown algae Cystoseira myriophylloides, Laminaria digitata, and Fucus spiralis against the tomato pathogens Verticillium dahliae and Agrobacterium tumefaciens was evaluated in vitro and in the greenhouse. A significant inhibition of growth was observed only with methanolic seaweed extracts (MSE). Disease resistance was assessed in the greenhouse against Verticillium wilt using spray application of aqueous seaweed extracts (ASE) on the whole plant or using seed imbibition. Both methods significantly reduced disease severity whatever the algal species, though protection observed after seed treatments was higher than that observed after spray treatment. Spray application of ASE from C. myriophylloides and F. spiralis also resulted in significant reduction of Crown gall disease caused by the bacterial pathogen A. tumefaciens. ASE-treated plants had significantly higher levels of activity of defense enzymes polyphenol oxidase and peroxidase compared to the control. ASE did not inhibit mycelium growth of V. dahliae or development of A. tumefaciens in vitro; it is therefore suggested that induced resistance is probably the main mechanism of protection afforded by ASE.

Antimicrobial activity of endophytic fungi from olive tree leaves

Abstract: In this study, the antimicrobial potential of three fungal endophytes from leaves of Olea europaea L. was evaluated and the host plant extract effect in the antimicrobial activity was examined. The volatile compounds produced by endophytes were identified by GC/MS and further correlated with the antimicrobial activity. In potato dextrose agar, both Penicillium commune and Penicillium canescens were the most effective inhibiting Gram-positive and -negative bacteria (up to 2.7-fold compared to 30 µg/mL chloramphenicol), whereas Alternaria alternata was most effective inhibiting yeasts (up to 8.0-fold compared to 25 μg/mL fluconazole). The presence of aqueous leaf extract in culture medium showed to induce or repress the antimicrobial activity, depending on the endophytic species. In the next step, various organic extracts from both A. alternata mycelium and cultured broth were prepared; being ethyl acetate extracts displayed the widest spectrum of anti-microorganisms at a minimum inhibitory concentration ≤0.095 mg/mL. The volatile composition of the fungi that displayed the highest (A. alternata) and the lowest (P. canescens) antimicrobial activity against yeasts revealed the presence of six volatiles, being the most abundant components (3-methyl-1-butanol and phenylethyl alcohol) ascribed with antimicrobial potentialities. Overall the results highlighted for the first time the antimicrobial potential of endophytic fungi from O. europaea and the possibility to be exploited for their antimicrobial agents.

Exploring the Antimicrobial and Antitumor Potentials of Streptomyces sp. AGM12-1 Isolated from Egyptian Soil.

Abstract: The occurrence of extensive antibiotics resistant bacteria increased the demands for mining out new sources of antimicrobial agents. Actinomycetes, especially Streptomyces sp. have grasped considerable attention worldwide due to production of many useful bioactive metabolites. In the present study, a total of 52 actinomycetes were isolated from agricultural soil samples in Beni-Suef, Egypt. All isolates were characterized based on colony morphology, mycelium coloration, and pigment diffusion. They were screened for their capabilities to show antimicrobial activities against different indicator microorganisms, and only 20 isolates have shown significant antimicrobial activities against at least one of the tested indicator microorganisms. The isolate AGM12-1 was active against all tested microorganisms and showed a marked antitumor activity with IC50 3.3 and 1.1μg/ml against HCT-116 and HepG-2 cell lines respectively. It was genotypically characterized as Streptomyces sp. with the presence of PKS Π biosynthetic gene cluster. Mannitol, ammonium sulfate, pH 7, 2% inoculum size and incubation for 11 days at 30 °C were the optimum conditions that used to maximize the production and hence allowed purification of one active antimicrobial compound to homogeneity using HPLC with a molecular mass of m/z 488.05. NMR structural elucidation showed that this compound was a diketopiperazine derivative.

Valorization of spent oyster mushroom substrate and laccase recovery through successive solid state cultivation of Pleurotus, Ganoderma, and Lentinula strains.

Abstract: Spent mushroom substrate (SMS) of Pleurotus ostreatus was supplemented with wheat bran and soybean flour in various proportions to obtain C/N ratios of 10, 20, and 30, and their effect was evaluated in successive cultivation of Pleurotus ostreatus, Pleurotus pulmonarius, Ganoderma adspersum, Ganoderma resinaceum, and Lentinula edodes strains with respect to mycelium growth rate, biomass concentration, recovery of the enzyme laccase and crude exopolysaccharides, and also with additional fruiting body production. All fungi showed the highest growth rate on unamended SMS (C/N 30), with G. resinaceum being the fastest colonizer (Kr = 9.84 mm day−1), while biomass concentration maximized at C/N 10. Moreover, supplementation affected positively laccase activity, with P. pulmonarius furnishing the highest value (44,363.22 U g−1) at C/N 20. On the contrary, L. edodes growth, fruiting, and laccase secretion were not favored by SMS supplementation. Fruiting body formation was promoted at C/N 30 for Ganoderma and at C/N 20 for Pleurotus species. Exopolysaccharide production of further studied Pleurotus strains was favored at a C/N 20 ratio, at the initial stage of SMS colonization. The obtained results support the potential effective utilization of supplemented SMS for laccase production from Ganoderma spp. and for new fruiting body production of Pleurotus spp.

Interactions affect hyphal growth and enzyme profiles in combinations of coniferous wood-decaying fungi of Agaricomycetes.

Abstract: Fomitopsis pinicola is a species of Polyporales frequently encountered in Nordic temperate and boreal forests In nature, the fungus causes destructive brown rot in wood, colonizing tree trunks often occupied by other Basidiomycota species We mimicked these species-species interactions by introducing F pinicola to five white rot species, all common saprotrophs of Norway spruce Hyphal interactions and mycelial growth in various combinations were recorded, while activities of lignocellulose-acting CAZymes and oxidoreductases were followed in co-cultures on two different carbon-source media Of the species, Phlebia radiata and Trichaptum abietinum were the strongest producers of lignin-modifying oxidoreductases (laccase, manganese peroxidase) when evaluated alone, as well as in co-cultures, on the two different growth media (low-nitrogen liquid medium containing ground coniferous wood, and malt extract broth) F pinicola was an outstanding producer of oxalic acid (up to 61 mM), whereas presence of P radiata prevented acidification of the growth environment in the liquid malt-extract cultures When enzyme profiles of the species combinations were clustered, time-dependent changes were observed on wood-supplemented medium during the eight weeks of growth End-point acidity and production of mycelium, oxalic acid and oxidoreductase activities, in turn clustered the fungal combinations into three distinct functional groups, determined by the presence of F pinicola and P radiata, by principal component analysis Our findings indicate that combinations of wood-decay fungi have dramatic dynamic effects on the production of lignocellulose-active enzymes, which may lead to divergent degradative processes of dead wood and forest litter

Effects of Pisolithus tinctorius and Cenococcum geophilum inoculation on pine in copper-contaminated soil to enhance phytoremediation.

Abstract: We used Pisolithus tinctorius and Cenococcum geophilum to determine the copper (Cu) resistance of ectomycorrhizal (ECM) fungi and their potential for improving phytoremediation of Cu-contaminated soil by Chinese red pine (Pinus tabulaeformis). The results showed that nutrient accumulation in C. geophilum mycelium was significantly lower under higher Cu concentrations in the soil, which was not observed in P. tinctorius. Meanwhile, P. tinctorius exhibited greater Cu tolerance than C. geophilum. Inoculation with ECM fungi significantly improved the growth of pine shoots planted in polluted soil in pot experiments (p < 0.01). The total accumulated Cu in pine seedlings planted in Cu-contaminated soil increased by 72.8% and 113.3% when inoculated with P. tinctorius and C. geophilum, respectively, indicating that ECM fungi may help their host to phytoextract heavy metals. Furthermore, the majority of the total absorbed metals remained in the roots, confirming the ability of ECM fungi to promote heavy metal phytostabilization. There were no differences between the effects of the two fungi in helping the host stabilize and absorb Cu, even though they have different Cu tolerances. Inoculation with ECM fungi can benefit plant establishment in polluted environments and assist plants with phytoremediating heavy-metal-contaminated soils.

The pH-responsive transcription factor PacC regulates mycelial growth, fruiting body development, and ganoderic acid biosynthesis in Ganoderma lucidum.

Abstract: Ganoderma lucidum is a medicinal macrofungus that is widely used in traditional Chinese medicine. Nonetheless, the scarcity of basic biological studies of this organism has hindered the further development of its commercial value. The pH-responsive transcription factor PacC/Rim101 governs the adaptation to environmental pH, the development and the secondary metabolism of many fungi. In this study, a homologue of PacC/Rim101 that encodes GlPacC was identified in the higher basidiomycete G. lucidum. GlPacC is composed of 807 amino acids and contains three typical C2H2 zinc-finger domains, two potential PEST domains, a putative PKA phosphorylation site, and a putative nuclear localization signal (NLS). GlPacC was transcribed at a high level when the fungus was under neutral and alkaline conditions, and silencing of GlPacC impaired the fungal response to ambient pH. The distance between the hyphal branches (of vegetative hyphae and aerial hyphae) was significantly increased in the GlPacC-silenced strains. The GlPacC-silenced strains grew abnormally or became sickly on solid culture medium and were unable to form primordia and fruiting bodies. The ganoderic acid content, levels of the sqs and ls transcripts, and contents of the metabolic intermediates squalene and lanosterol were all up-regulated in the GlPacC-silenced strains. Our results indicate that GlPacC is functional and plays complex roles in mycelial growth, fruiting body development and ganoderic acid biosynthesis in G. lucidum.

Sensitivity of Fusarium oxysporum f. sp. niveum to Prothioconazole and Thiophanate-Methyl and Gene Mutation Conferring Resistance to Thiophanate-Methyl

Abstract: Fusarium wilt, incited by the fungus Fusarium oxysporum f. sp. niveum, is a soilborne disease that affects watermelon production worldwide. Approaches for effective management of Fusarium wilt in watermelon are limited. Studies conducted in recent years indicated that prothioconazole and thiophanate-methyl reduced the disease significantly under field conditions. However, effects of the fungicides on different life stages of F. oxysporum f. sp. niveum and potential existence of fungicide resistance in F. oxysporum f. sp. niveum populations are unknown. In the present study, effects of prothioconazole and thiophanate-methyl on mycelium growth and spore germination of F. oxysporum f. sp. niveum isolates collected in watermelon fields in Georgia were determined. In vitro mycelium growth studies indicated that all 100 isolates evaluated were sensitive to prothioconazole; the effective concentration that suppressed mycelium growth by 50% ranged from 0.75 to 5.69 μg/ml (averaged 1.62 μg/ml). In contrast, 33 and 4% of the isolates were resistant to thiophanate-methyl at 10 and 100 μg/ml, respectively. Microconidial germination assays showed that 36 and 64% of the isolates tested were sensitive or intermediately sensitive to prothioconazole at 100 μg/ml but the fungicide did not inhibit spore germination at 10 μg/ml. Sequencing a portion of the β-tubulin gene of eight isolates resistant or sensitive to thiophanate-methyl indicated that fungicide resistance was associated with a point mutation at nucleotide position 200, resulting in a substitution of phenylalanine by tyrosine. This is the first report of isolates of F. oxysporum resistant to thiophanate-methyl. Results of the research suggest that prothioconazole may be a viable option for management of Fusarium wilt of watermelon whereas thiophanate-methyl should be used judiciously due to the existence of isolates resistant to the fungicide.

Design, Cultivation and Application of Load-Bearing Mycelium Components

Abstract: MycoTree is a spatial branching structure made out of load-bearing mycelium components. Its geometry was designed using 3D graphic statics, utilising compression-only form to enable the weak material to perform structurally. Using only mycelium and bamboo, the structure represents a provocative vision of how one may move beyond the mining of our construction materials from the earth’s crust to their cultivation; how achieving stability through geometry rather than through material strength opens up possibilities to use weaker materials structurally and safely; and ultimately, how newly developed cultivated materials in combination with informed structural design have the potential to propose an alternative to established building materials for a more sustainable construction industry.

Production of a potential liquid plant bio-stimulant by immobilized Piriformospora indica in repeated-batch fermentation process

Abstract: Piriformospora indica, a mycorrhizal-like fungus able to establish associations with roots of a wide range of plants, supporting plant nutrition and increasing plant resistance and tolerance to stress, was shown to solubilise phosphate applied in the form of animal bone char (HABO) in fermentation systems The process of P solubilisation was caused most likely by proton extrusion and medium pH lowering The fungal mycelium was successfully immobilized/retained in a polyurethane foam carrier Further employment of the immobilized mycelium in repeated-batch fermentation process resulted in at least 5 cycles of P solubilization The concentration of soluble P increased during the experiment with 10 and 30 g HABO l−1 and at the end of the 5th batch cycle reached 408 and 120 mg l−1, respectively The resulting final liquid product, without or with solubilized phosphate, was found to significantly increase plant growth and P plant uptake It can be used as a biostimulant containing microbial plant growth-promoting substances and soluble P derived from renewable sources (HABO) thus supporting the development of sustainable agro-ecosystems

An in vivo whole-plant experimental system for the analysis of gene expression in extraradical mycorrhizal mycelium

Abstract: Arbuscular mycorrhizal fungi (AMF) establish beneficial mutualistic symbioses with land plants, receiving carbon in exchange for mineral nutrients absorbed by the extraradical mycelium (ERM) With the aim of obtaining in vivo produced ERM for gene expression analyses, a whole-plant bi-dimensional experimental system was devised and tested with three host plants and three fungal symbionts In such a system, Funneliformis mosseae in symbiosis with Cichorium intybus var foliosum, Lactuca sativa, and Medicago sativa produced ERM whose lengths ranged from 98 ± 08 to 208 ± 12 m per plant Since ERM produced in symbiosis with C intybus showed the highest values for the different structural parameters assessed, this host was used to test the whole-plant system with F mosseae, Rhizoglomus irregulare, and Funneliformis coronatus The whole-plant system yielded 1–7 mg of ERM fresh biomass per plant per harvest, and continued producing new ERM for 6 months Variable amounts of high-quality and intact total RNA, ranging from 15 to 65 μg RNA/mg ERM fresh weight, were extracted from the ERM of the three AMF isolates Ammonium transporter gene expression was successfully determined in the cDNAs obtained from ERM of the three fungal symbionts by RT-qPCR using gene-specific primers designed on available (R irregulare) and new (F mosseae and F coronatus) ammonium transporter gene sequences The whole-plant experimental system represents a useful research tool for large production and easy collection of ERM for morphological, physiological, and biochemical analyses, suitable for a wide variety of AMF species, for a virtually limitless range of host plants and for studies involving diverse symbiotic interactions

Bioactive sesquiterpenes from an endophytic fungus Bipolaris sorokiniana isolated from a popular medicinal plant Costus speciosus

Abstract: Bipolaris sorokiniana, a fungal endophyte, was isolated from the leaves of Costus speciosus, a popular medicinal plant used to control diabetes. Fermentation of the fungus in potato dextrose broth and chromatographic purification of the ethyl acetate (EtOAc) extracts of the culture broth and mycelium yielded two rare sesquiterpenes helminthosporal acid (1) and helminthosporol (2), together with ergosterol. Compounds 1 and 2 showed a strong phytotoxic effect on lettuce seed germination and toxicity against brine shrimps. Compound 1 also showed antifungal activity. Complete assignments of 1H and 13C NMR data of compound 1 are described for the first time.

Isolation, Culture and Characterization of Hirsutella sinensis Mycelium from Caterpillar Fungus Fruiting Body.

Abstract: The caterpillar fungus Ophiocordyceps sinensis (previously called Cordyceps sinensis) has been used for centuries in Asia as a tonic to improve health and longevity. Recent studies show that O. sinensis produces a wide range of biological effects on cells, laboratory animals and humans, including anti-fatigue, anti-infection, anti-inflammatory, antioxidant, and anti-tumor activities. In view of the rarity of O. sinensis fruiting bodies in nature, cultivation of its anamorph mycelium represents a useful alternative for large-scale production. However, O. sinensis fruiting bodies harvested in nature harbor several fungal contaminants, a phenomenon that led to the isolation and characterization of a large number of incorrect mycelium strains. We report here the isolation of a mycelium from a fruiting body of O. sinensis and we identify the isolate as O. sinensis' anamorph (also called Hirsutella sinensis) based on multi-locus sequence typing of several fungal genes (ITS, nrSSU, nrLSU, RPB1, RPB2, MCM7, β-tubulin, TEF-1α, and ATP6). The main characteristics of the isolated mycelium, including its optimal growth at low temperature (16°C) and its biochemical composition, are similar to that of O. sinensis fruiting bodies, indicating that the mycelium strain characterized here may be used as a substitute for the rare and expensive O. sinensis fruiting bodies found in nature.

Design of a load-bearing mycelium structure through informed structural engineering

Abstract: MycoTree is a spatial branching structure made out of load-bearing mycelium components. Its geometry was designed using 3D graphic statics, utilizing compression-only form to enable the weak material to perform structurally. Using only mycelium and bamboo, the structure represents a provocative vision of how one may move beyond the mining of our construction materials from the earth’s crust to their cultivation and urban growth; how achieving stability through geometry rather than through material strength opens up possibilities to use weaker materials structurally and safely; and ultimately, how regenerative resources in combination with informed structural design have the potential to propose an alternative to established building materials for a more sustainable construction industry. mycelium; bamboo; alternative building materials; closed-loop; circular; prototypology; 3D graphic statics; compression-only

Compatibility and incompatibility in hyphal anastomosis of arbuscular mycorrhizal fungi

Abstract: Arbuscular mycorrhizal fungi (AMF), which live in symbiosis with 80 % of plants, are not able to grow when separated from their hosts. Spore germination is not host-regulated and germling growth is shortly arrested in the absence of host roots. Germling survival chances may be increased by hyphal fusions (anastomoses), which allow access to nutrients flowing in the extraradical mycelium (ERM). Perfect anastomoses, occurring with high frequency among germlings and the ERM of the same isolate, show protoplasm continuity and disappearance of hyphal walls. A low frequency of perfect fusions has been detected among co-specific genetically different isolates, although fungal nuclei have been consistently detected in all perfect fusions, suggesting active nuclear migration. When plants of different taxa establish symbioses with the same AMF species, anastomoses between ERM spreading from single root systems establish a common mycelium, which is an essential element to plant nutrition and communication. The interaction among mycelia produced by different isolates may also lead to pre-fusion incompatibility which hinders anastomosis formation, or to incompatibility after fusion, which separates the hyphal compartments. Results reported here, obtained by analyses of hyphal compatibility/incompatibility in AMF, suggest that anastomosis formation and establishment of protoplasm flow, fundamental to the maintenance of mycelial physiological and genetic continuity, may affect the fitness of these ecologically important biotrophic fungi.