Catechol-Bearing Polyketide Derivatives from Sparticola junci.

Sparticols A (1) and B (2), two catechol-bearing naphthalenedioxy derivatives, were isolated from the submerged culture of the Spanish broom inhabiting Dothideomycetes fungus, Sparticola junci. The structures of 1 and 2 were established by NMR spectroscopic analysis and high-resolution mass spectrometry. The 8S absolute configuration of their ß-hydroxy functionalities was determined by ECD-TDDFT. Both compounds exhibited inhibitory activity against Staphylococcus aureus with an MIC value of 66.6 µg/mL. Polyketides 1 and/or 2 may be associated with pathways cascading to seco-spirodioxynapthalene derivatives.

COX Inhibitory and Cytotoxic Naphthoketal-Bearing Polyketides from Sparticola junci.

Axenic fermentation on solid rice of the saprobic fungus Sparticola junci afforded two new highly oxidized naphthalenoid polyketide derivatives, sparticatechol A (1) and sparticolin H (2) along with sparticolin A (3). The structures of 1 and 2 were elucidated on the basis of their NMR and HR-ESIMS spectroscopic data. Assignment of absolute configurations was performed using electronic circular dichroism (ECD) experiments and Time-Dependent Density Functional Theory (TDDFT) calculations. Compounds 1-3 were evaluated for COX inhibitory, antiproliferative, cytotoxic and antimicrobial activities. Compounds 1 and 2 exhibited strong inhibitory activities against COX-1 and COX-2. Molecular docking analysis of 1 conferred favorable binding against COX-2. Sparticolin H (2) and A (3) showed a moderate antiproliferative effect against myelogenous leukemia K-562 cells and weak cytotoxicity against HeLa and mouse fibroblast cells.

Alpha-Glucosidase- and Lipase-Inhibitory Phenalenones from a New Species of Pseudolophiostoma Originating from Thailand.

The alpha-glucosidase- and lipase-inhibitory activities of three phenalenones (1-3) and one phenylpropanoid (4) from the ethyl acetate extracts of a Pseudolophiosptoma sp. are described. They represent the first secondary metabolites reported from the genus Pseudolophiostoma. Scleroderolide (1) and sclerodione (2) exhibited potent α-glucosidase- and porcine-lipase-inhibitory activity during primary screening, with better IC50 values compared to the positive controls, N-deoxynojirimycin and orlistat. In silico techniques were employed to validate the probable biological targets and elucidate the mechanism of actions of phenalenones 1 and 2. Both compounds exhibited strong binding affinities to both alpha-glucosidase and porcine lipase through H-bonding and π-π interactions. Interestingly, favorable in silico ADME (absorption, distribution, metabolism, and excretion) properties such as gastrointestinal absorption were also predicted using software.

Sparticolins A-G, Biologically Active Oxidized Spirodioxynaphthalene Derivatives from the Ascomycete Sparticola junci.

To explore the chemical diversity of metabolites from new species of Dothideomycetes, the ex-type strain of Sparticola junci was investigated. Seven highly oxygenated and functionalized spirodioxynaphthalene natural products incorporating carboxyalkylidene-cyclopentanoid (1-4), carboxyl-functionalized oxabicyclo[3.3.0]octane (5-6), and annelated 2-cyclopentenone/δ-lactone (7) units, sparticolins A-G, were isolated from submerged cultures of the fungus. Their chemical structures including their relative (and absolute) configurations were established through spectroscopic and X-ray crystallographic analyses. Sparticolin B (2) exhibited inhibitory activity against the Gram-positive bacteria Bacillus subtilis, Micrococcus luteus, and Staphylococcus aureus, while sparticolin G (7) showed antifungal activities against Schizosaccharomyces pombe and Mucor hiemalis. All other sparticolins were only weakly active against S. aureus and also showed weak activities against the nematode Caenorhabditis elegans. Compounds 2 and 7 also showed moderate cytotoxic activities against seven mammalian cell lines.

Biofilm Inhibitory Abscisic Acid Derivatives from the Plant-Associated Dothideomycete Fungus, Roussoella sp.

Roussoella species are well recorded from both monocotyledons and dicotyledons. As part of a research program to discover biologically active compounds from plant-associated Dothideomycetes in Thailand, the strain Roussoella sp. (MFLUCC 17-2059), which represents an undescribed species, was isolated from Clematis subumbellata Kurz, fermented in yeast-malt medium and explored for its secondary metabolite production. Bioassay-guided fractionation of the crude extract yielded the new abscisic acid derivative, roussoellenic acid (1), along with pestabacillin B (2), a related congener, and the cyclodipeptide, cyclo(S-Pro-S-Ile) (3). The structure of 1 was determined by 2D NMR spectroscopy and HR-ESIMS data analysis. Compounds 1 and 2 showed inhibitory activity on biofilm formation by Staphylococcus aureus. The biofilm formation of S. aureus was reduced to 34% at 16 µg/mL by roussoellenic acid (1), while pestabacillin B (2) only showed 36% inhibition at 256 µg/mL. In addition, compound 1 also had weak cytotoxic effects on L929 murine fibroblasts and human KB3-1 cancer cells.

Morphological characteristics and phylogenetic evidence reveal two new species and the first report of Comoclathris (Pleosporaceae, Pleosporales) on dicotyledonous plants from China.

Two novel Comoclathris species were identified from dicotyledonous plants (Clematis sp. and Xanthocerassorbifolium) in China. The results were supported by morphological characters and Maximum Likelihood (ML) and Bayesian Inference (BI) analyses. Multi-gene phylogenetic analyses of the ITS, LSU, SSU and rpb2 sequences revealed two new species Comoclathrisclematidis and C.xanthoceratis, which are phylogenetically distinct. The new species are phylogenetically closely related to C.arrhenatheri. However, they are distinguishable from C.arrhenatheri by having comparatively larger asci and ascospores. This study improves our knowledge of Comoclathris as no species has been previously described from China. This suggests such taxa may be rare and it is likely that new taxa will be discovered from hosts and environments that have not yet been extensively investigated.

Four new species of Dothideomycetes (Ascomycota) from Pará Rubber (Heveabrasiliensis) in Yunnan Province, China.

The tropical areas in southern and south-western Yunnan are rich in fungal diversity. Additionally, the diversity of seed flora in Yunnan Province is higher than in other regions in China and the abundant endemic species of woody plants provide favourable substrates for fungi. Rubber plantations in Yunnan Province are distributed over a large area, especially in Xishuangbanna. During a survey of rubber-associated fungi in Yunnan Province, China, dead rubber branches with fungal fruiting bodies were collected. Morphological characteristics and multigene phylogenetic analyses (ITS, LSU, SSU, rpb2 and tef1-α) revealed four distinct new species, described herein as Melomastiapuerensis, Nigrogranalincangensis, Pseudochaetosphaeronemalincangensis and Pseudochaetosphaeronemaxishuangbannaensis. Detailed descriptions, illustrations and phylogenetic trees are provided to show the taxonomic placements of these new species.

Diversity of Ascomycota in Jilin: Introducing Novel Woody Litter Taxa in Cucurbitariaceae.

Cucurbitariaceae has a high biodiversity worldwide on various hosts and is distributed in tropical and temperate regions. Woody litters collected in Changchun, Jilin Province, China, revealed a distinct collection of fungi in the family Cucurbitariaceae based on morphological and molecular data. Phylogenetic analyses of the concatenated matrix of the internal transcribed spacer (ITS) region, the large subunit (LSU) of ribosomal DNA, the RNA polymerase II subunit (rpb2), the translation elongation factor 1-alpha (tef1-α) and ß-tubulin (ß-tub) genes indicated that the isolates represent Allocucurbitaria and Parafenestella species based on maximum likelihood (ML), maximum parsimony (MP) and Bayesian analysis (BPP). We report four novel species: Allocucurbitaria mori, Parafenestella changchunensis, P. ulmi and P. ulmicola. The importance of five DNA markers for species-level identification in Cucurbitariaceae was determined by Assemble Species by Automatic Partitioning (ASAP) analyses. The protein-coding gene ß-tub is determined to be the best marker for species level identification in Cucurbitariaceae.

Synopsis of Leptosphaeriaceae and Introduction of Three New Taxa and One New Record from China.

Leptosphaeriaceae, a diverse family in the order Pleosporales, is remarkable for its scleroplectenchymatous or plectenchymatous peridium cells. Four Leptosphaeriaceae species were discovered and studied during the investigation of saprobic fungi from plant substrates in China. Novel taxa were defined using multiloci phylogenetic analyses and are supported by morphology. Based on maximum likelihood (ML) and Bayesian inference (BI) analyses, these isolates represent three novel taxa and one new record within Leptosphaeriaceae. A new genus, Angularia, is introduced to accommodate Angularia xanthoceratis, with a synopsis chart for 15 genera in Leptosphaeriaceae. This study also revealed a new species, Plenodomus changchunensis, and a new record of Alternariaster centaureae-diffusae. These species add to the increasing number of fungi known from China.

Fungal-Bacterial Networks in the Habitat of SongRong (Tricholoma matsutake) and Driving Factors of Their Distribution Rules.

Soil origin, mycorrhizal plant partners and environmental factors affect the growth and development of SongRong (Tricholoma matsutake). In order to clarify the relationships of fungi-bacteria networks and various influence factors in the habitat of SongRong, we chose three collection sites with a Quercus mongolica pure forest (plot A without SongRong was used as the control sample site), Q. mongolica mixed Rhododendron dauricum (plot B) and Q. mongolica mixed with R. dauricum and Pinus densiflora (plot C). By using high-throughput sequencing, we obtained a total of 4930 fungal and 55501 bacterial amplicon sequence variants (ASVs) based on internally transcribed spacer ribosomal RNA (ITS rRNA) and 16S ribosomal RNA (16S rRNA) sequencing via the Illumina NovaSeq platform. In the habitat soil of SongRong (plot B and plot C), alpha or beta diversity and species compositions of fungi and bacteria were different from plot A. The fungal-bacterial networks follow the selection rule that few dominant genera account for the greater relative abundance. Forest types, but not the host itself, drove the fungal-bacterial networks of the forest soil, and soil physicochemical characteristics and texture affected their abundance. The abundance of Tricholoma was affected by the fungal and bacterial abundance in the habitat.

Morphological and Phylogenetic Evidence Reveal Five New Telamonioid Species of Cortinarius (Agaricales) from East Asia.

Five new Cortinarius species, C. neobalaustinus, C. pseudocamphoratus, C. subnymphatus, C. wuliangshanensis and C. yanjiensis spp. nov., are proposed based on a combination of morphological and molecular evidence. Cortinarius neobalaustinus is characterized by a very weakly hygrophanous and yellowish-brown to brown pileus and small and weakly verrucose basidiospores. Cortinarius pseudocamphoratus can be characterized by a viscid pileus, a strongly unpleasant smell, amygdaloid to somewhat ellipsoid basidiospores and lageniform to subfusiform cheilocystidia. Cortinarius subnymphatus is identified by a strongly hygrophanous pileus that is reddish-brown with a black-brown umbo, a yellowish universal veil and ellipsoid to subamygdaloid basidiospores. Cortinarius wuliangshanensis is characterized by a moderately to strongly hygrophanous, translucently striated and yellowish to reddish-brown pileus and rather weakly and moderately verrucose basidiospores. Cortinarius yanjiensis is distinguished by a weakly to moderately hygrophanous and yellowish to brown pileus and moderately to rather strongly verrucose basidiospores. The phylogenetic analyses were performed with maximum likelihood and Bayesian inference methods based on the data set of nuc rDNA ITS1-5.8S-ITS2 (ITS), D1-D2 domains of nuc 28S rDNA (28S) and RNA polymerase II second largest subunit (rpb2), and the results show that C. neobalaustinus, C. wulianghsanensis and C. yanjiensis cluster in sect. Illumini, C. pseudocamporatus belongs to sect. Camphorati and C. subnymphatus belongs to sect. Laeti. In addition, a study of basidiospores under field emission scanning electron microscopy (FESEM) was conducted. An identification key for the five new species and related species from China is also provided.

Antiproliferative and Cytotoxic Cytochalasins from Sparticola triseptata Inhibit Actin Polymerization and Aggregation.

Laying the groundwork on preliminary structure-activity relationship study relating to the disruptive activity of cytochalasan derivatives on mammalian cell actin cytoskeleton, we furthered our study on the cytochalasans of the Dothideomycetes fungus, Sparticola triseptata. A new cytochalasan analog triseptatin (1), along with the previously described cytochalasans deoxaphomin B (2) and cytochalasin B (3), and polyketide derivatives cis-4-hydroxy-6-deoxyscytalone (4) and 6-hydroxymellein (5) were isolated from the rice culture of S. triseptata. The structure of 1 was elucidated through NMR spectroscopic analysis and high-resolution mass spectrometry (HR-ESI-MS). The relative and absolute configurations were established through analysis of NOESY spectroscopic data and later correlated with experimental electronic circular dichroism and time-dependent density functional theory (ECD-TDDFT) computational analysis. Compounds 1 and 2 showed cytotoxic activities against seven mammalian cell lines (L929, KB3.1, MCF-7, A549, PC-3, SKOV-3, and A431) and antiproliferative effects against the myeloid leukemia K-562 cancer cell line. Both 1 and 2 were shown to possess properties inhibiting the F-actin network, prompting further hypotheses that should to be tested in the future to enable a well-resolved concept of the structural implications determining the bioactivity of the cytochalasin backbone against F-actin.

Integrating Different Lines of Evidence to Establish a Novel Ascomycete Genus and Family (Anastomitrabeculia, Anastomitrabeculiaceae) in Pleosporales.

A novel genus, Anastomitrabeculia, is introduced herein for a distinct species, Anastomitrabeculia didymospora, collected as a saprobe on dead bamboo culms from a freshwater stream in Thailand. Anastomitrabeculia is distinct in its trabeculate pseudoparaphyses and ascospores with longitudinally striate wall ornamentation. A new family, Anastomitrabeculiaceae, is introduced to accommodate Anastomitrabeculia. Anastomitrabeculiaceae forms an independent lineage basal to Halojulellaceae in Pleosporales and it is closely related to Neohendersoniaceae based on phylogenetic analyses of a combined LSU, SSU and TEF1α dataset. In addition, divergence time estimates provide further support for the establishment of Anastomitrabeculiaceae. The family diverged around 84 million years ago (MYA) during the Cretaceous period, which supports the establishment of the new family. The crown and stem age of Anastomitrabeculiaceae was also compared to morphologically similar pleosporalean families.

Reappraisal of Immotthia in Dictyosporiaceae, Pleosporales: Introducing Immotthia bambusae sp. nov. and Pseudocyclothyriella clematidis comb. et gen. nov. Based on Morphology and Phylogeny.

Immotthia is a poorly known genus, and currently, no DNA sequence data are available to ascertain its proper phylogenetic placement and evolutionary relationships with other bitunicate fungi. To date, there are only two species accepted in the genus. During our ongoing research study of bambusicolous fungi in southwest China and Thailand, a fungus associated with stromata of Hypoxylon sp. was found on dead bamboo culms in Loei Province, Thailand. Preliminary morphological identification revealed that the fungal collection belongs to Immotthia. A novel species, Immotthia bambusae, is introduced herein based on a comparison of morphological characteristics with the type specimen of I. hypoxylon (≡ Amphisphaeria hypoxylon Ellis and Everh.), a synonym of I. atrograna (Cooke and Ellis) M. E. Barr. Phylogenetic analyses of a concatenated ITS, LSU, SSU, and TEF1-α DNA sequence matrix showed that Immotthia belongs to Dictyosporiaceae, Pleosporales. Despite I. bambusae strains constituting a supported subclade, they are nested with the genus Pseudocoleophoma. Pseudocoleophoma clematidis is morphologically different from all other Pseudocoleophoma species, while its conidial characteristics are similar to Cyclothyriella. Multigene phylogenetic analyses showed that P. clematidis formed a clade basal to Immotthia, separated from Pseudocoleophoma with strong statistical support. Therefore, we introduce a monotypic genus, Pseudocyclothyriella Phukhams. and Phookamsak, gen. nov. to accommodate the single species, Pseudocyclothyriella clematidis (Phukhams. and K. D. Hyde) Phukhams. and Phookamsak, comb. nov. Detailed descriptions, color micrographs, and phylogenetic trees to show the placement of the new taxa are provided. In addition, an updated taxonomic treatment of the genera Immotthia and Pseudocyclothyriella is also provided based on the study of the type materials and phylogeny generated from DNA sequence data.

Cortinarius subsalor and C. tibeticisalor spp. nov., two new species from the section Delibuti from China.

Cortinarius subsalor and C. tibeticisalor, belonging to the section Delibuti, are described from China as new to science. Cortinarius subsalor has been found to be associated with Lithocarpus trees in subtropical China and resembling C. salor, but it differs from the later by having slender basidiomata and the narrower basidiospores. Cortinarius tibeticisalor was collected from eastern Tibetan Plateau, associated with Abies. It differs from other species within sect. Delibuti by having olive tinge of mature or dried basidiomata and bigger basidiospores. The molecular data also support C. subsalor and C. tibeticisalor as new species. The phylogenetic analyses and biogeography of sect. Delibuti are discussed and a key to the species of this section currently known in the world is provided.

Volatile Constituents of Endophytic Fungi Isolated from Aquilaria sinensis with Descriptions of Two New Species of Nemania.

Algae, bacteria, and fungi, as well as higher plants, produce a wide variety of secondary metabolites known as natural products. Natural products are well known as remarkable sources of many therapeutic agents. The genus Nemania is a wood-decaying fungus that belongs to family Xylariaceae. Nemania is often found as an endophyte in diverse hosts and some species are known to produce useful secondary metabolites. In this study, two Nemania species were isolated as an endophytic fungus from Aquilaria sinensis. Multi-gene phylogenetic studies showed that the newly described strains of Nemania are new to science, and this is the first report of Nemania from the host Aquilaria. One of the fermented species, Nemania aquilariae (KUMCC 20-0268), resulted in five sesquiterpenoids, which were previously reported from agarwood, and their structures were identified by gas chromatography-mass spectrometry (GC-MS). In addition, five different media were investigated in vitro to optimize conditions for growing the fungal biomass of Nemania aquilariae and N. yunnanensis.

Two novel species of Neoaquastroma (Parabambusicolaceae, Pleosporales) with their phoma-like asexual morphs.

The monotypic genus Neoaquastroma (Parabambusicolaceae, Pleosporales) was introduced for a microfungus isolated from a collection of dried stems of a dicotyledonous plant in Thailand. In this paper, we introduce two novel species, N. bauhiniae and N. krabiense, in this genus. Their asexual morphs comprise conidiomata with aseptate and hyaline conidia. Neoaquastroma bauhiniae has ascomata, asci and ascospores that are smaller than those of N. krabiense. Descriptions and illustrations of N. bauhiniae and N. krabiense are provided and the two species compared with the type species of the genus, N. guttulatum. Evidence for the introduction of the new taxa is also provided from phylogenetic analysis of a combined dataset of partial LSU, SSU, ITS and tef1 sequence data. The phylogenetic analysis revealed a distinct lineage for N. bauhiniae and N. krabiense within the family Parabambusicolaceae.