Thailand possesses a rich diversity of orchid species that, in turn, live in symbiosis with a wide variety of fungi. Such endophytes have the potential to produce secondary metabolites with bioactivity against orchid and/or human pathogens. The orchid-associated fungal strain Daldinia eschscholtzii was found to produce a diverse range of aromatic polyketides including the new naphthalene derivatives daldionin, nodulones B and C, and daldinones F and G along with eight known compounds. Daldionin possesses an unprecedented oxane-linked binaphthyl ring system. These compounds demonstrate the high diversity of structural variations that are constructed during fungal biosynthesis, and the results include important observations concerning the biosynthesis of binaphthyl derivatives. Daldionin was found to have weak antiproliferative activity against HUVEC and K-562 cell lines. All but one of the isolated compounds showed moderate antimicrobial activity towards at least one of the four tested microbial strains.
This paper briefly discusses the history of fungal taxonomy and contributes to the concepts and the importance of ranking genera, families and orders. We propose recommendations for introducing species into appropriate ranks such as genera, families and orders, as well as the rationale to maintain species in one genus or segregate one genus into several genera. Various ways to rank fungi have commonly been based on morphological and phylogenetic species concepts. More recently, the use of molecular clocks, coupled with estimates of divergence times, has provided insights into how to assign species and support their establishment at different taxonomic hierarchical levels. Case studies are given from the order Botryosphaeriales and Pleosporales, and the genera Camarosporium, Colletotrichum, Diaporthe, Pestalotiopsis, Lophiostoma and Agaricus to demonstrate taxonomic ambiguities and the subjectivity in classification of fungi.
Periconia thailandica is a new hyphomycetous species found on bamboo culms collected in Kamphaeng Phet, Thailand. We herein introduce P. thailandica based on morphological characters and molecular analysis. Phylogenetic analyses of combined ITS, LSU and SSU sequence data place the new species in Periconia (Pleosporales) where it forms a distinct clade in the genus. The new species is characterized by brown, 4−7-septate conidiophores with terminal, polyblastic, acropetally proliferating, globose conidiogenous cells, and light to dark brown, globose, verrucose conidia. The morphological comparisons between P. thailandica and other known Periconia species are discussed. The new species is introduced to accommodate this taxon with a detailed description and morphological illustrations.
A new stemphol derivative, stemphol 1- O-β-D-galactopyranoside (1b), together with three known metabolites, stemphol (1a), indole-3-carboxylic acid, and kojic acid, has been isolated from the ethyl acetate extract of cultures of Gaeumannomyces amomi BCC4066, an endophytic fungus found on healthy parts of ginger ( Alpinia malaccensis; Thai name Kha-pa). The structure of 1b was established via spectroscopic methods, including 2D NMR measurements and GC/MS experiments.
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