Studies on the Genus Pyrenopolyporus (Hypoxylaceae) in Thailand Using a Polyphasic Taxonomic Approach.

Over the past two decades, hypoxylaceous specimens were collected from several sites in Thailand. In this study, we examined their affinity to the genus Pyrenopolyporus using macroscopic and microscopic morphological characters, dereplication of their stromatal secondary metabolites using ultrahigh performance liquid chromatography coupled to diode array detection and ion mobility tandem mass spectrometry (UHPLC-DAD-IM-MS/MS), and molecular phylogenetic analyses. We describe and illustrate five novel species and a new record for the country, present multi-locus phylogenetic analyses that show the distinction between the proposed species, and provide proteomic profiles of the fungi using matrix associated laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF/MS) for the first time. Based on our findings, this strategy is useful as a complementary tool to distinguish species between Daldinia and Pyrenopolyporus in a consistent way with the phylogenetic analysis.

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.

The Suhomyces clade: from single isolate to multiple species to disintegrating sex loci.

Candida tanzawaensis clade members are now placed in Suhomyces. The group was virtually unknown until the early 2000s. Here, we review progress made on Suhomyces over the last two decades and provide data from reports of new members of the group from distant localities worldwide, their habitats and a new study of mating loci that helps explain earlier failed compatibility tests. Phylogenetic studies indicate early diverging members are mostly associated with plants, but later diverging species are usually fungus-feeding insect associates. The genome of S. tanzawaensis was known to have a heterothallic mating allele arrangement with a single MAT α idiomorph. For this review, we generate sequence data and compare the MAT gene arrangement of 30 strains from nine Suhomyces species. These varied from MAT α loci containing mating genes α1 and α2, hypothetical MAT a loci without detectable mating genes a1 and a2 to truncated, possibly completely dissociated MAT loci with intraspecific variation. The absence of a second MAT in a genome locus precludes the possibility of mating type switching. Sympatric speciation likely occurred after MAT locus deterioration began in isolated habitats. Although asexual reproduction may be an effective short-term strategy, theory predicts it will not endure over the extreme long term.

Cytochalasans Act as Inhibitors of Biofilm Formation of Staphylococcus Aureus.

During the course of our ongoing work to discover new inhibitors of biofilm formation of Staphylococcus aureus from fungal sources, we observed biofilm inhibition by cytochalasans isolated from cultures of the ascomycete Hypoxylon fragiforme for the first time. Two new compounds were purified by a bioassay-guided fractionation procedure; their structures were elucidated subsequently by nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry (HR-MS). This unexpected finding prompted us to test further cytochalasans from other fungi and from commercial sources for comparison. Out of 21 cytochalasans, 13 showed significant inhibition of Staphylococcus aureus biofilm formation at subtoxic levels. These findings indicate the potential of cytochalasans as biofilm inhibitors for the first time, also because the minimum inhibitory concentrations (MIC) are independent of the anti-biofilm activities. However, cytochalasans are known to be inhibitors of actin, making some of them very toxic for eukaryotic cells. Since the chemical structures of the tested compounds were rather diverse, the inclusion of additional derivatives, as well as the evaluation of their selectivity against mammalian cells vs. the bacterium, will be necessary as next step in order to develop structure-activity relationships and identify the optimal candidates for development of an anti-biofilm agent.

Disentangling cryptic species with isaria-like morphs in Cordycipitaceae.

A new genus and eight new species, all with isaria-like phialides, are described in Cordycipitaceae from Thailand. The new genus, Samsoniella, is segregated from Akanthomyces based on morphological and molecular evidence. Samsoniella differs from Akanthomyces in producing orange cylindrical to clavate stromata with superficial perithecia and orange conidiophores with isaria-like phialides and white to cream conidia. A new combination for CBS 240.32, originally identified as Paecilomyces farinosus (Isaria farinosa), and CBS 262.58, originally identified as Penicillium alboaurantium, respectively, is made in Samsoniella. Two new species, Samsoniella aurantia and S. inthanonensis, are described from lepidopteran larvae. Two new species of Cordyceps, C. blackwelliae and C. lepidopterorum, were also found on coleopteran and lepidopteran larvae. Both produce isaria-like morphs with globose phialides and attenuated long necks and white mycelium in culture. The authors established a sexual-asexual link for Cordyceps javanica (= Isaria javanica) on lepidopteran larvae. Four new species, Akanthomyces kanyawimiae, A. sulphureus, A. thailandicus, and A. waltergamsii, were pathogenic on spiders, with some strains of A. kanyawimiae also found on unidentified insect larvae. These four species of Akanthomyces occur on the underside of leaves and produce white to cream white powdery conidia, whereas S. aurantia and S. inthanonensis were found in leaf litter and produce bright orange stromata and synnemata with white conidia. Another new combination, Akanthomyces ryukyuensis, is proposed. Phylogenetic analyses based on a combined data set comprising the nuc rDNA region encompassing the internal transcribed spacers 1 and 2 along with the 5.8S rDNA (ITS), nuc 28S rDNA (28S), partial sequences of translation elongation factor 1-α gene (TEF1), and the genes for RNA polymerase II largest (RPB1) and second-largest (RPB2) subunits strongly support the delimitation of these new species of Cordyceps, Akanthomyces, and in a new genus Samsoniella in Cordycipitaceae.

Purpureocillium, a new genus for the medically important Paecilomyces lilacinus.

Paecilomyces lilacinus was described more than a century ago and is a commonly occurring fungus in soil. However, in the last decade this fungus has been increasingly found as the causal agent of infections in man and other vertebrates. Most cases of disease are described from patients with compromised immune systems or intraocular lens implants. In this study, we compared clinical isolates with strains isolated from soil, insects and nematodes using 18S rRNA gene, internal transcribed spacer (ITS) and partial translation elongation factor 1-α (TEF) sequences. Our data show that P. lilacinus is not related to Paecilomyces, represented by the well-known thermophilic and often pathogenic Paecilomyces variotii. The new genus name Purpureocillium is proposed for P. lilacinus and the new combination Purpureocillium lilacinum is made here. Furthermore, the examined Purpureocillium lilacinum isolated grouped in two clades based on ITS and partial TEF sequences. The ITS and TEF sequences of the Purpureocillium lilacinum isolates used for biocontrol of nematode pests are identical to those causing infections in (immunocompromised) humans. The use of high concentrations of Purpureocillium lilacinum spores for biocontrol poses a health risk in immunocompromised humans and more research is needed to determine the pathogenicity factors of Purpureocillium lilacinum.