Depicting the Chemical Diversity of Bioactive Meroterpenoids Produced by the Largest Organism on Earth.

In this investigation, we explored the diversity of melleolide-type meroterpenoids produced by Armillaria ostoyae, one of the largest and oldest organisms on Earth, using extracts from liquid and solid fermentation media. The study unveiled three unprecedented dimeric bismelleolides and three novel fatty-acid-substituted congeners, along with 11 new and 21 known derivatives. The structures were elucidated by 1D and 2D NMR spectroscopy and HRESI-MS, and ROESY spectral analysis for relative configurations. Absolute configurations were determined from crystal structures and through ECD spectra comparison. A compound library of melleolide-type meroterpenoids facilitated metabolomics-wide associations, revealing production patterns under different culture conditions. The library enabled assessments of antimicrobial and cytotoxic activities, revealing that the Δ2,4 double bond is not crucial for antifungal activity. Cytotoxicity was linked to the presence of an aldehyde at C1, but lost with hydroxylation at C13. Chemoinformatic analyses demonstrated the intricate interplay of chemical modifications on biological properties. This study marks the first systematic exploration of Armillaria spp. meroterpenoid diversity by MS-based untargeted metabolomics, offering insight into structure-activity relationships through innovative chemoinformatics.

Bioprospection of Tenellins Produced by the Entomopathogenic Fungus Beauveria neobassiana.

Fungi are known as prolific producers of bioactive secondary metabolites with applications across various fields, including infectious diseases, as well as in biological control. However, some of the well-known species are still underexplored. Our current study evaluated the production of secondary metabolites by the entomopathogenic fungus Beauveria neobassiana from Thailand. The fermentation of this fungus in a liquid medium, followed by preparative high-performance liquid chromatography (HPLC) purification, resulted in the isolation of a new tenellin congener, namely pretenellin C (1), together with five known derivatives (2-6). Their chemical structures were elucidated by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy in combination with high-resolution electrospray ionization mass spectrometry (HR-ESI-MS). We evaluated the antimicrobial and cytotoxic activities from all isolated compounds, as well as their inhibitory properties on biofilm formation by Staphylococcus aureus. Generally, tenellins displayed varying antibiofilm and cytotoxic effects, allowing us to propose preliminary structure-activity relationships (SARs). Among the tested compounds, prototenellin D (2) exhibited the most prominent antibiofilm activity, while its 2-pyridone congener, tenellin (4), demonstrated potent cytotoxic activity against all tested cell lines. Given the fact that the biological activities of the tenellins have so far been neglected in the past, our study could provide a good starting point to establish more concise structure-activity relationships in the near future.

Cytotoxic cytochalasans from cultures of the fungus Metarhizium brunneum TBRC-BCC 79240.

Fourteen new cytochalasans, brunnesins A-N (1-14), along with eleven known compounds, were isolated from the culture extracts of the insect pathogenic fungus Metarhizium brunneum strain TBRC-BCC 79240. The compound structures were established by spectroscopy, X-ray diffraction analysis, and electronic circular dichroism. Compound 4 exhibited antiproliferative activity against all cell lines tested (mammalian), with 50% inhibition concentration (IC50) values ranging from 2.09 to 16.8 µg mL-1. Compounds 6 and 16 were shown to be bioactive only against non-cancerous Vero cells (IC50 4.03 and 0.637 µg mL-1, respectively) whereas compounds 9 and 12 were bioactive only against NCI-H187 small-cell lung cancer cells (IC50 18.59 and 18.54 µg mL-1, respectively). Compounds 7, 13, and 14 showed cytotoxicity against NCI-H187 and Vero cell lines with IC50 values ranging from 3.98-44.81 µg mL-1.

Is Hyperdermium Congeneric with Ascopolyporus? Phylogenetic Relationships of Ascopolyporus spp. (Cordycipitaceae, Hypocreales) and a New Genus Neohyperdermium on Scale Insects in Thailand.

During surveys of insect pathogenic fungi (IPF) in Thailand, fungi associated with scale insects and plants were found to represent five new species of the genus Ascopolyporus in Cordycipitaceae. Their macroscopic features resembled both Hyperdermium and Ascopolyporus. Morphological comparisons with the type and known Ascopolyporus and Hyperdermium species and phylogenetic evidence from a multigene dataset support the appointment of a new species of Ascopolyporus. Moreover, the data also revealed that the type species of Hyperdermium, H. caulium, is nested within Ascopolyporus, suggesting that Hyperdermium is congeneric with Ascopolyporus. The specimens investigated here differ from other Ascopolyporus species by phenotypic characters including size and color of stromata. Phylogenetic analyses of combined LSU, TEF1, RPB1 and RPB2 sequences strongly support the notion that these strains are distinct from known species of Ascopolyporus, and are proposed as Ascopolyporus albus, A. galloides, A. griseoperitheciatus, A. khaoyaiensis and A. purpuratus. Neohyperdermium gen. nov. is introduced for other species originally assigned to Hyperdermium and Cordyceps occurring on scale insects and host plants as epiphytes, accommodating two new combinations of Hyperdermium pulvinatum and Cordyceps piperis.

Comprehensive treatise of Hevansia and three new genera Jenniferia, Parahevansia and Polystromomyces on spiders in Cordycipitaceae from Thailand.

Collections of pathogenic fungi found on spiders from Thailand were selected for a detailed taxonomic study. Morphological comparison and phylogenetic analyses of the combined ITS, LSU, tef1, rpb1 and rpb2 sequence data indicated that these specimens formed new independent lineages within the Cordycipitaceae, containing two new genera occurring on spiders, i.e. Jenniferia gen. nov. and Polystromomyces gen. nov. Two new species in Jenniferia, J.griseocinerea sp. nov. and J.thomisidarum sp. nov., are described. Two strains, NHJ 03510 and BCC 2191, initially named as Akanthomycescinereus (Hevansiacinerea), were shown to be part of Jenniferia. By including sequences of putative Hevansia species from GenBank, we also revealed Parahevansia as a new genus with the ex-type strain NHJ 666.01 of Pa.koratensis, accommodating specimens previously named as Akanthomyceskoratensis (Hevansiakoratensis). One species of Polystromomyces, Po.araneae sp. nov., is described. We established an asexual-sexual morph connection for Hevansianovoguineensis (Cordycipitaceae) with ex-type CBS 610.80 and proposed a new species, H.minuta sp. nov. Based on characteristics of the sexual morph, Hevansia and Polystromomyces share phenotypic traits by producing stipitate ascoma with fertile terminal heads; however, they differ in the shape and colour of the stipes. Meanwhile, Jenniferia produces non-stipitate ascoma with aggregated superficial perithecia forming a cushion. A new morphology of ascospores in Jenniferia is described, illustrated and compared with other species in Cordycipitaceae.

Phylogeny- and morphology-based recognition of new species in the spider-parasitic genus Gibellula (Hypocreales, Cordycipitaceae) from Thailand.

Thailand is known to be a part of what is called the Indo-Burma biodiversity hotspot, hosting a vast array of organisms across its diverse ecosystems. This is reflected by the increasing number of new species described over time, especially fungi. However, a very few fungal species from the specialized spider-parasitic genus Gibellula have ever been reported from this region. A survey of invertebrate-pathogenic fungi in Thailand over several decades has led to the discovery of a number of fungal specimens with affinities to this genus. Integration of morphological traits into multi-locus phylogenetic analysis uncovered four new species: G. cebrennini, G. fusiformispora, G. pigmentosinum, and G. scorpioides. All these appear to be exclusively linked with torrubiella-like sexual morphs with the presence of granulomanus-like asexual morph in G. pigmentosinum and G. cebrennini. A remarkably high host specificity of these new species towards their spider hosts was revealed, and for the first time, evidence is presented for manipulation of host behavior in G. scorpioides.

Phylogenetic and morphological classification of Ophiocordyceps species on termites from Thailand.

Seven new species occurring on termites are added to Ophiocordyceps - O. asiatica, O. brunneirubra, O. khokpasiensis, O. mosingtoensis, O. pseudocommunis, O. pseudorhizoidea and O. termiticola, based on morphological and molecular phylogenetic evidence. O. brunneirubra possesses orange to reddish-brown immersed perithecia on cylindrical to clavate stromata. O. khokpasiensis, O. mosingtoensis and O. termiticola have pseudo-immersed perithecia while O. asiatica, O. pseudocommunis and O. pseudorhizoidea all possess superficial perithecia, reminiscent of O. communis and O. rhizoidea. Phylogenetic analyses based on a combined dataset comprising the internal transcribed spacer regions (ITS) and the largest subunit (LSU) of the ribosomal DNA, partial regions of the elongation factor 1-α (TEF) and the largest and second largest subunits for the RNA polymerase genes (RPB1, RPB2) strongly support the placement of these seven new species in Ophiocordyceps.

New species of Ophiocordyceps unilateralis, an ubiquitous pathogen of ants from Thailand.

Ophiocordyceps unilateralis is an ubiquitous pathogen of ants with hidden phylogenetic diversity associated with host specificity. In this study, we describe two new species to this species complex: Ophiocordyceps septa and Ophiocordyceps rami. Both were found on unidentified ants of the genus Camponotus (C. sp.1 and C. sp2 respectively). Ophiocordyceps septa is very similar to Ophiocordyceps polyrhachis-furcata, Ophiocordyceps camponoti-leonardi, and Ophiocordyceps camponoti-saundersi (found respectively on the ants Polyrhachis furcata, Camponotus leonardi, and Camponotus saundersi) but differs in the size, the shape and the septation of the ascospores, while O. rami is clearly identifiable with macro-morphological features including multiple stromata similar to Ophiocordyceps halabalaensis on Camponotus gigas. A thorough morphological examination was also provided for O. polyrhachis-furcata, O. camponoti-leonardi, and O. camponoti saundersi, showing that the first was apparently distinguishable from the others by the absence of septation of the ascospores. A combined molecular phylogeny also supports O. septa and O. rami as distinct new species.

Phenolic glycosides from the filamentous fungus Acremonium sp. BCC 14080.

New phenolic mono- and digalactopyranosides (1 and 2), their aglycone KS-501a (3), and a new phenolic 4-O-methylglucopyranoside (4) were isolated from the filamentous fungus Acremonium sp. BCC 14080. Structures of these compounds were elucidated by extensive MS and NMR spectroscopic analyses. Compound 1 displayed anti-HSV-1 activity with an IC(50) value of 7.2 microM. Compound 3 exhibited activity against Plasmodium falciparum K1 with an IC(50) value of 9.9 microM.