Die seltenen, aber weltweit verbreiteten Fruchtkörper von Geastrum triplex (= Geastrum indicum, Halskrausen-Erdstern, Fundort: Niedersachsen) zeigen als morphologische Besonderheit einen zentralen Sporenbehälter, der mit dem Öffnen während der Reifung zu Tage tritt. Durch eine Pore an der Spitze entweichen die Sporen. Erdsterne sind in der Volksmedizin der Indianer Nordamerikas und in China bekannt, aber zu zäh zum genussvollen Konsum.
Riley, Robert et al., Extensive sampling of basidiomycete genomes demonstrates inadequacy of the white-rot/brown-rot paradigm for wood decay fungi, Proceedings of the National Academy of Sciences of the United States of America (2014), 111(27), 9923-9928
Basidiomycota (basidiomycetes) make up 32% of the described fungi and include most wood-decaying species, as well as pathogens and mutualistic symbionts. Wood-decaying basidiomycetes have typically been classified as either white rot or brown rot, based on the ability (in white rot only) to degrade lignin along with cellulose and hemicellulose. Prior genomic comparisons suggested that the two decay modes can be distinguished based on the presence or absence of ligninolytic class II peroxidases (PODs), as well as the abundance of enzymes acting directly on cryst. cellulose (reduced in brown rot). To assess the generality of the white-rot/brown-rot classification paradigm, the authors compared the genomes of 33 Basidiomycetes, including four newly sequenced wood decayers, and performed phylogenetically informed principal-components anal. (PCA) of a broad range of gene families encoding plant biomass-degrading enzymes. The newly sequenced Botryobasidium botryosum and Jaapia argillacea genomes lack PODs but possess diverse enzymes acting on cryst. cellulose, and they group close to the model white-rot species Phanerochaete chrysosporium in the PCA. Furthermore, lab. assays showed that both B. botryosum and J. argillacea can degrade all polymeric components of woody plant cell walls, a characteristic of white rot. The authors also found expansions in reducing polyketide synthase genes specific to the brown-rot fungi. The results suggest a continuum rather than a dichotomy between the white-rot and brown-rot modes of wood decay. A more nuanced categorization of rot types is needed, based on an improved understanding of the genomics and biochem. of wood decay.
Schwenk, Daniel et al., Injury-Induced Biosynthesis of Methyl-Branched Polyene Pigments in a White-Rotting Basidiomycete, Journal of Natural Products (2014), 77(12), 2658-2663.
A stereaceous basidiomycete was investigated with regard to its capacity to produce yellow pigments after phys. injury of the mycelium. Two pigments were isolated from mycelial exts., and their structures were elucidated by ESIMS and one- and two-dimensional NMR methods. The structures were identified as the previously undescribed polyenes (3Z,5E,7E,9E,11E,13Z,15E,17E)-18-methyl-19-oxoicosa-3,5, 7,9,11,13,15,17-octaenoic acid (1) and (3E,5Z,7E,9E,11E,13E,15Z,17E,19E)-20-methyl-21-oxodocosa- 3,5,7,9,11,13,15,17,19-nonaenoic acid (2). Stable-isotope feeding with [1-13C]acetate and L-[methyl-13C] methionine demonstrated a polyketide backbone and that the introduction of the sole Me branch is most likely S-adenosyl-L-methionine-dependent. Dose-dependent inhibition of Drosophila melanogaster larval development was obsd. with both polyenes in concns. between 12.5 and 100 μM. GI50 values for 1 and 2 against HUVEC (K-562 cells) were 71.6 and 17.4 μM (15.4 and 1.1 μM), resp., whereas CC50 values for HeLa cells were virtually identical (44.
The genetic structure of the A mating-type locus of Lentinula edodes.
Au, Chun Hang; Wong, Man Chun; Bao, Dapeng; Zhang, Meiyan; Song, Chunyan; Song, Wenhua; Law, Patrick Tik Wan; Kues, Ursula; Kwan, Hoi Shan, Gene (2014), 535, 184-190.
The Shiitake mushroom, Lentinula edodes (Berk.) Pegler is a tetrapolar basidiomycete with two unlinked mating-type loci, commonly called the A and B loci. Identifying the mating-types in shiitake is important for enhancing the breeding and cultivation of this economically-important edible mushroom. We observed unique genomic organization of the locus in L. edodes which exhibits atypical gene order and multiple repetitive elements around its A locus.
HR-MALDI-MS Imaging Assisted Screening of β-Carboline Alkaloids Discovered from Mycena metata
Jaeger, Robert J. R.; Lamshoeft, Marc; Gottfried, Sebastian; Spiteller, Michael; Spiteller, Peter, Journal of Natural Products (2013), 76, 127-134.
Fruiting bodies of Mycena metata were screened for the presence of new secondary metabolites by means of HPLC-UV, LC-HR-ESIMS, and high-resolution matrix-assisted laser desorption/ionization mass spectrometry imaging (HR-MALDI-MS imaging). Thus, a new β-carboline alkaloid, 6-hydroxymetatacarboline D (I), was isolated from fruiting bodies of M. metata.
Hypoxyvermelhotins A-C, new pigments from Hypoxylon lechatii sp. nov
Kuhnert, Eric; Heitkaemper, Simone; Fournier, Jacques; Surup, Frank; Stadler, Marc, Fungal Biology (2014), 118, 242-252.
A new species of Hypoxylon was discovered, based on material collected in French Guiana and recognized on the basis of new combination of morphological characters in comparison with type and authentic material of macroscopically similar taxa. Aside from vermelhotin, previously isolated from cultures of endophytic fungi, we identified three novel congeners, for which the trivial names hypoxyvermelhotins A-C were proposed. Like vermelhotin, they constitute orange-red pigments and a preliminary biol. characterization revealed them to have rather strong cytotoxic and moderate to weak antimicrobial effects.
Separation and purification of laccases from two different fungi using aqueous two-phase extraction
Prinz, Axel; Hoenig, Jacqueline; Schüttmann, Ina; Zorn, Holger; Zeiner, Tim, Process Biochemistry (Oxford) (2014), 49, 335-346.
In this study a polyethylene glycol 3000 (PEG 3000)-phosphate aqueous two-phase system at 25 °C and pH 7 was successfully used for laccase purification and separation. Two modes of operation are proposed depending on the aim of the purification task.
(Schizophyllan is a homoglucan with a β-1,3-linked backbone and β-1,6-linked side chains of single glucose units at every other residue).
Ditengou et al. Volatile signalling by sesquiterpenes from ectomycorrhizal fungi reprogrammes root architecture, Nature communications (2015), 6, 6279
The mutualistic association of roots with ectomycorrhizal fungi promotes plant health and is a hallmark of boreal and temperate forests worldwide. In the pre-colonization phase, before direct contact, lateral root (LR) production is massively stimulated, yet little is known about the signals exchanged during this step. Here, we identify sesquiterpenes (SQTs) as biologically active agents emitted by Laccaria bicolor while interacting with Populus or Arabidopsis. We show that inhibition of fungal SQT production by lovastatin strongly reduces LR proliferation and that (-)-thujopsene, a low-abundance SQT, is sufficient to stimulate LR formation in the absence of the fungus. Further, we show that the ectomycorrhizal ascomycote, Cenococcum geophilum, which cannot synthesize SQTs, does not promote LRs. We propose that the LR-promoting SQT signal creates a win-win situation by enhancing the root surface area for plant nutrient uptake and by improving fungal access to plant-derived carbon via root exudates.
Inonotus obliquus, ein Basidiomycet aus der Klasse der Agaricomycetes macht unter dem Namen “Chaga” Schlagzeilen. Der Birkenparasit bildet schwarze Sklerotien mit dem Aussehen von Holzkohle. Das gepulverte Sklerotium dient neuerdings als Kaffeeersatz oder Zutat „Chagaccino“.
Inonotus obliquus, a basidiomycet of the class of Agaricomycetes has entered hedlines under the name “chaga”. The birch parasite forms black sklertotia looking like charcoal. The powdered sklerotium has recently been used as a substitute of coffee powder or as an additive to produce „Chagaccino“.