Optimized isolation of 7,7′-biphyscion starting from Cortinarius rubrophyllus, a chemically unexplored fungal species rich in photosensitizers

Mushrooms such as the dermocyboid Cortinarius rubrophyllus are characterized by strikingly colorful fruiting bodies. The molecular dyes responsible for such colors recently experienced a comeback as photoactive compounds with remarkable photophysical and photobiological properties. One of them-7,7'-biphyscion-is a dimeric anthraquinone that showed promising anticancer effects in the low nanomolar range under blue-light irradiation. Compared to acidic anthraquinones, 7,7'-biphyscion was more efficiently taken up by cells and induced apoptosis after photoactivation. However, seasonal collection of mushrooms producing this compound, low extraction yields, and tricky fungal identification hamper further developments to the clinics. To bypass these limitations, we demonstrate here an alternative approach utilizing a precursor of 7,7'-biphyscion, i.e., the pre-anthraquinone flavomannin-6,6'-dimethyl ether, which is abundant in many species of the subgenus Dermocybe. Controlled oxidation of the crude extract significantly increased the yield of 7,7'-biphyscion by 100%, which eased the isolation process. We also present the mycochemical and photobiological characterization of the yet chemically undescribed species, i.e. C. rubrophyllus. In total, eight pigments (1-8) were isolated, including two new glycosylated anthraquinones (1 and 2). Light-dependent generation of singlet oxygen was detected for the first time for emodin-1-O-beta-D-glucopyranoside (3) [photophysical measurement: Phi(Delta) =0.11 (CD3OD)]. Furthermore, emodin (7) was characterized as promising compound in the photocytotoxicity assay with EC50-values in the low micromolar range under irradiation against cells of the cancer cell lines AGS, A549, and T24.Metals in Catalysis, Biomimetics & Inorganic Material

Species Delimitation in Taxonomically Difficult Fungi: The Case of Hymenogaster

False truffles are ecologically important as mycorrhizal partners of trees and evolutionarily highly interesting as the result of a shift from epigeous mushroom-like to underground fruiting bodies. Since its first description by Vittadini in 1831, inappropriate species concepts in the highly diverse false truffle genus Hymenogaster has led to continued confusion, caused by a large variety of prevailing taxonomical opinions.In this study, we reconsidered the species delimitations in Hymenogaster based on a comprehensive collection of Central European taxa comprising more than 140 fruiting bodies from 20 years of field work. The ITS rDNA sequence dataset was subjected to phylogenetic analysis as well as clustering optimization using OPTSIL software.Among distinct species concepts from the literature used to create reference partitions for clustering optimization, the broadest concept resulted in the highest agreement with the ITS data. Our results indicate a highly variable morphology of H. citrinus and H. griseus, most likely linked to environmental influences on the phenology (maturity, habitat, soil type and growing season). In particular, taxa described in the 19(th) century frequently appear as conspecific. Conversely, H. niveus appears as species complex comprising seven cryptic species with almost identical macro- and micromorphology. H. intermedius and H. huthii are described as novel species, each of which with a distinct morphology intermediate between two species complexes. A revised taxonomy for one of the most taxonomically difficult genera of Basidiomycetes is proposed, including an updated identification key. The (semi-)automated selection among species concepts used here is of importance for the revision of taxonomically problematic organism groups in general

Mycorrhization of fagaceae forests within mediterranean ecosystems

Mediterranean Fagaceae forests are valuable due to their ecological and socioeconomic aspects. Some profitable plant species, such as Castanea (timber and chestnut), Quercus (timber and cork), and Fagus (timber), encounter in this habitat the excellent edaphoclimatic conditions to develop. All Fagaceae plants are commonly associated to ECM fungal species, which are found in these forests in quite stable communities, mainly enriched in Russulaceae and Telephoraceae species. Currently, the Mediterranean Basin is considered as one of the global biodiversity hotspots, since many of their endemic plant species are not found elsewhere and are now under threat. Due to climate changing and introduction of disease agents, Fagaceae forests are facing an adaptation challenge to both biotic and abiotic threats. Although ECM communities are highly disturbed by climate factors and tree disease incidence, they could play an important role in increasing water availability to the plant and also improving plant tree defense against pathogens. Recent advances, namely, on genomics and transcriptomics, are providing tools for increasing the understanding of Fagaceae mycorrhization process and stress responses to biotic and abiotic stresses. Such studies can provide new information for the implementation of the most adequate management policies for protecting threaten Mediterranean forests.info:eu-repo/semantics/publishedVersio

Short communication. Response of bacterial community composition to long-term applications of different composts in agricultural soils

Differences in the bacterial community composition of agricultural soils caused by a long-term (12 year) application of different composts were identified by cultivation-dependent and -independent methods (PCR-DGGE and 16S rRNA clone libraries). The number of colony forming units indicated that the successive incorporation of organic amendments increased the bacterial abundance (6.41-5.66 log10 cfu g�1 dry soil) compared to control and mineral soils (5.54-3.74 log10 cfu g�1 dry soil). Isolated bacteria were dominated by Actinobacteria, whereby compost-amended soils and green compost-amended soils showed, respectively, higher number of members of Actinobacteria (100% and 64%) than control and mineral soils (50% and 40%). The 16S rRNA clone libraries were dominated by Proteobacteria (43%), Acidobacteria (21%) and Actinobacteria (13%). Proteobacteria and Actinobacteria were most abundant in compost amended soils while Acidobacteria were more frequently found in mineral fertilizer and control soils. Partial 16S rRNA gene clone libraries revealed a higher bacterial diversity than cultivation. In conclusion, we found differences of bacterial community composition with a cultivation approach and clone libraries between compost amended soils and control and mineral soil.Se estudiaron las comunidades bacterianas de suelos agrícolas enmendados durante 12 años con diferentes tipos de compost, mediante el empleo de técnicas de cultivo en placa y técnicas moleculares (PCR-DGGE y genotecas de ARNr 16S). El cultivo en placa mostró un aumento del número de bacterias en los suelos enmendado con diferentes composts (6,41-5,66 log10 cfu g�1 suelo), respecto a los suelos no enmendados o con fertilización mineral (5,54-3,74 log10 cfu g�1 suelo). Esta técnica reveló que las Actinobacterias componen la mayoría de las bacterias identificadas en placa, encontrando un mayor número en los suelos enmendados con diferentes compost (100%-64%) frente a los no enmendados o con fertilización mineral (50%-40%). Las genotecas permitieron identificar además de Actinobacterias (13%), la presencia de Proteobacterias (43%) y Acidobacterias (21%). En los suelos enmendados con compost predominaron Proteobacterias y Actinobacterias, mientras que en los suelos sin enmendar y con fertilización mineral predominaron las Acidobacterias. Las genotecas mostraron mayor diversidad bacteriana que el método de cultivo en placa. En conclusión, los datos obtenidos mediante cultivo en placa y con genotecas mostraron diferencias en la composición de la comunidad microbiana entre suelos enmendados con compost y aquellos sin enmendar y con fertilización mineral

Mushrooms - an unrevealed source for promising photopharmaceuticals

Metals in Catalysis, Biomimetics & Inorganic Material

The microbial communities and fruiting of edible ectomycorrhizal mushrooms

The competition between edible ectomycorrhizal fungi (EMF) and other ectomycorrhizal fungi have been studied in greenhouse and in the field taking into account different environmental conditions and using molecular tools as well as morphological methods. Approximately 100 ectomycorrhizal species were identified in soil fungal communities in productive areas of Boletus edulis sensu lato and in truffières of Tuber magnatum and Tuber borchii. The bacterial communities occurring in T. magnatum and T. borchii fruiting bodies during different stages of their maturation were also characterized. Alpha Proteobacteria, were found as major constituents of the bacterial community associated with truffle ascoma, independentely of the degree of maturation. These bacteria include members of the Sinorhizobium-Ensifer and Rhizobium-Agrobacterium groups, and Bradyrhizobium spp ., which are well known for their ability to fix atmospheric nitrogen. Our studies raise two important questions about truffle biology: 1) can the composition of microbial soil communities infuence EMF fruiting body production ? 2) can nitrogen fixing bacteria play a role in truffle nutrition