New furan derivatives from Annulohypoxylon spougei fungus.

Two new furan derivatives, annulofurans A-B (1-2), together with six known compounds were isolated from Annulohypoxylon spougei fungus. The structures were determined based on NMR and mass spectrometry data. The absolute configurations of annulofurans A-B were determined by Electronic Circular Dichroism (ECD) experiment and comparisons with the experimental ECD spectra of synthesized stereoisomers. The evaluation of the effects on radish and ruzi grass radicle elongation by the isolated compounds showed that annulofuran A affected radicle elongation of ruzi grass. The known 2-hydroxyphenylacetic acid methyl ester (7) had significant effects against both radish and ruzi grass radicle elongation, which were comparable to the commercial herbicide, glyphosate.

Diversity of fungi associated with macroalgae from an estuarine environment and description of Cladosporium rubrum sp. nov. and Hypoxylon aveirense sp. nov.

Fungal communities associated with macroalgae remain largely unexplored. To characterize algicolous fungal communities using culture dependent methods, macroalgae were collected from different sampling sites in the Ria de Aveiro estuary, Portugal. From a collection of 486 isolates that were obtained, 213 representative isolates were selected through microsatellite-primed PCR (MSP-PCR) fingerprinting analysis. The collection yielded 33 different genera, which were identified using the ITS region of the rDNA. The results revealed that the most abundant taxa in all collections were Acremonium-like species: Alternaria, Cladosporium, Leptobacillium and Penicillium. The fungal community composition varied with macroalgae species. Through multilocus phylogenetic analyses based on ITS, tub2, tef1-α and actA sequences, in addition to detailed morphological data, we propose Cladosporium rubrum sp. nov. (type strain=CMG 28=MUM 19.39) and Hypoxylon aveirense sp. nov. (type strain=CMG 29=MUM 19.40) as novel species.

Daldiconoids A-G: 3,4-Secolanostane triterpenoids from the fruiting bodies of Daldinia concentrica and their anti-inflammatory activity.

Seven undescribed 3,4-secolanostane triterpenoids, daldiconoids A-G (1-7), were isolated from the fruiting bodies of Daldinia concentrica. Daldiconoid A (1) was a highly modified 4,6,28,29-tetranorlanostane triterpenoid alkaloid featuring an unusual δ-lactam fused with a flanking cyclopentenone architecture. Their structures were determined by spectroscopic data, NMR calculations coupled with the DP4+ analysis, X-ray single-crystal diffraction, and chemical transformation. The plausible biosynthetic pathway for 1 was proposed. Compounds 1, 2, and 4-6 inhibited the expressions of IL-1ß, IL-6, and TNF-α in lipopolysaccharide stimulated RAW264.7 cells at a concentration of 10 µM. Mechanistically, Compounds 1 and 2 blocked the JAK2/STAT3 signaling pathway induced by lipopolysaccharide.

Unique and Repeated Stwintrons (Spliceosomal Twin Introns) in the Hypoxylaceae.

Introns are usually non-coding sequences interrupting open reading frames in pre-mRNAs [D1,2]. Stwintrons are nested spliceosomal introns, where an internal intron splits a second donor sequence into two consecutive splicing reactions leading to mature mRNA. In Hypoxylon sp. CO27-5, 36 highly sequence-similar [D1,2] stwintrons are extant (sister stwintrons). An additional 81 [D1,2] sequence-unrelated stwintrons are described here. Most of them are located at conserved gene positions rooted deep in the Hypoxylaceae. Absence of exonic sequence bias at the exon-stwintron junctions and a very similar phase distribution were noted for both groups. The presence of an underlying sequence symmetry in all 117 stwintrons was striking. This symmetry, more pronounced near the termini of most of the full-length sister stwintrons, may lead to a secondary structure that brings into close proximity the most distal splice sites, the donor of the internal and the acceptor of the external intron. The Hypoxylon stwintrons were overwhelmingly excised by consecutive splicing reactions precisely removing the whole intervening sequence, whereas one excision involving the distal splice sites led to a frameshift. Alternative (mis)splicing took place for both sister and uniquely occurring stwintrons. The extraordinary symmetry of the sister stwintrons thus seems dispensable for the infrequent, direct utilisation of the distal splice sites.

Discovery of a new species of the Hypoxylon rubiginosum complex from Iran and antagonistic activities of Hypoxylon spp. against the Ash Dieback pathogen, Hymenoscyphus fraxineus, in dual culture.

During a survey of xylarialean fungi in Northern Iran, several specimens that showed affinities to the Hypoxylon rubiginosum complex were collected and cultured. A comparison of their morphological characters, combined with a chemotaxonomic study based on high performance liquid chromatography, coupled with diode array detection and mass spectrometry (HPLC-DAD/MS) and a multi-locus phylogeny based on ITS, LSU, rbp2 and tub2 DNA sequences, revealed a new species here described as Hypoxylon guilanense. In addition, Hypoxylon rubiginosum sensu stricto was also encountered. Concurrently, an endophytic isolate of the latter species showed strong antagonistic activities against the Ash Dieback pathogen, Hymenoscyphus fraxineus, in a dual culture assay in our laboratory. Therefore, we decided to test the new Iranian fungi for antagonistic activities against the pathogen, along with several cultures of other Hypoxylon species that are related to H. rubiginosum. Our results suggest that the antagonistic effects of Hypoxylon spp. against Hym. fraxineus are widespread and that they are due to the production of antifungal phomopsidin derivatives in the presence of the pathogen.