The taxonomy of Usnea in sub-Antarctic and Antarctic regions remains challenging because of morphological similarity among species. We analyzed 107 specimens from South Patagonia, the Falkland Islands, and Antarctic localities using 11 loci, including nine recently introduced markers. The concatenated phylogeny recovered five well-supported lineages. We evaluated alternative groupings of these predefined lineages using STACEY, treating each lineage as an indivisible minimal cluster. The five-lineage partition was recovered in 100% of retained trees at a collapse height of 1.0 × 10−5 and 59.69% at 1.0 × 10−4. Morphological species assignments did not correspond one-to-one with lineage membership. Specimens identified as U. antarctica were predominantly included in the antarctica lineage. Specimens identified as U. aurantiacoatra occurred in all five lineages, whereas those identified as U. trachycarpa were predominantly included in the trachycarpa lineage. Morphological characters such as apothecia, soredia, papillae, fibrils, and an axis-to-branch diameter ratio ≥0.5, showed high homoplasy, as indicated by low consistency (CI) and retention (RI) indices, and did not reliably distinguish the phylogenetic lineages. Geographic distributions differed among lineages. Within our sampling, aurantiacoatra lineage 1 was restricted to the Falkland Islands, the antarctica lineage was recovered from maritime Antarctic localities, and the trachycarpa lineage occurred in South Patagonia and the Falkland Islands. We treated the five lineages as operational taxonomic units (OTUs) rather than formally delimited species. This study provides a multilocus phylogenetic framework for evaluating lineage diversity in southern South America and Antarctica, while the formal taxonomic status of these lineages requires further integrative assessment.
Endophytic fungi were isolated from woody plants collected in Korea, and five species were identified as unrecorded species in Korea: Keithomyces apolzaniae, Muyocopron ficinum, Nagrajchalara neonawawii, Neodidymelliopsis negundinis, and Purimyces endophyticus. The isolates were obtained from the roots or twigs of Rhododendron mucronulatum, Corylus heterophylla, and Taxus cuspidata. Species identification was based on cultural and microscopic characteristics together with multilocus phylogenetic analyses using different combinations of ITS, LSU, SSU, TUB2, and RPB2 sequences, depending on the taxon. The isolates generally showed morphological characteristics consistent with previous descriptions and clustered with reference strains of the corresponding species in maximum-likelihood phylogenetic analyses. These findings add five endophytic fungal species to the Korean mycobiota and expand current knowledge of fungal diversity associated with woody plants.
Dermatophytosis requires environmental decontamination because dermatophyte spores can persist on contaminated surfaces for prolonged periods. However, regulatory frameworks in several countries rely solely on Trichophyton mentagrophytes to evaluate disinfectant efficacy, which may not represent the diversity of dermatophytes encountered in veterinary settings. In this study, we aimed to evaluate the disinfectant efficacy of four commercial disinfectants [quaternary ammonium compounds (QACs), potassium peroxymonosulfate (KMPS), iodine, and sodium dichloroisocyanurate (NaDCC)] against T. mentagrophytes, Trichophyton verrucosum, Microsporum canis, and Nannizzia gypsea at 25 °C and 4 °C. Minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were determined using broth dilution methods with a 30-min contact time; a time-kill assay was performed at the MFC of each disinfectant to assess fungicidal activity over 30 min. MICs were 125–64,000 ppm, with QACs showing the greatest variability among strains (32-fold). KMPS consistently showed an MFC/MIC ratio of 1 across all strains and temperatures, whereas QACs reached a ratio of 8 against T. mentagrophytes at 25 °C suggesting fungistatic activity. In the time-kill assay, all disinfectants achieved a ≥ 3-log10 reduction within 30 min, except QACs against T. mentagrophytes at 25 °C (2.85-log10). At 25 min, fewer samples reached this threshold at 4 °C than at 25 °C (16.7% vs. 43.8%, p = 0.007), but this difference was not observed at 30 min (p = 0.111). NaDCC showed the strongest temperature dependence. These preliminary findings indicate that the inclusion of additional dermatophyte species and low-temperature conditions in standardized disinfectant efficacy testing warrants further evaluation using multiple isolates.
Wood-inhabiting fungi represent a taxonomically and metabolically diverse group with potential as sources of bioactive compounds, yet their tyrosinase inhibitory activity remains poorly explored beyond a limited number of well-known medicinal species. In this study, we comparatively evaluated the tyrosinase inhibitory activity of cultured mycelial extracts from 49 phylogenetically verified strains of wood-inhabiting fungi belonging to the Hymenochaetales and Polyporales orders. Strains were cultivated under standardized conditions, and ethanol extracts prepared from three independent biological replicates were evaluated at concentrations of 0.1, 0.5, 1, and 5 mg/mL. Tyrosinase inhibitory activity varied markedly among the tested strains and generally increased with extract concentration. Hydnophlebia alachuana and Nigroporus vinosus showed particularly high activity, including substantial inhibition at the lowest concentration tested. These findings expand the range of wood-inhabiting fungi evaluated for tyrosinase inhibition and identify previously underexplored taxa as promising candidates for further investigation. The results provide a basis for prioritizing active fungal strains for chemical characterization and further evaluation of their tyrosinase-inhibitory potential.
Klebsiella pneumoniae is a major cause of both nosocomial and community-acquired infections, with hypervirulent (hvKP) strains causing severe disease in healthy individuals. In Southeastern Asia, diabetes mellitus is a recognized risk factor for hvKP-associated pyogenic liver abscesses. hvKP virulence is typically attributed to carriage of a large virulence plasmid encoding siderophore biosynthesis (iuc, iro) and mucoid regulator (rmpA, rmpA2) genes. Here, we analyzed 50 bloodstream isolates from Taipei, Taiwan, to investigate genomic and phenotypic characteristics of isolates from patients with or without diabetes mellitus. In diabetic patients and patients with liver abscesses, hvKP biomarkers were found in 66% (n = 33) and 64% (n = 32) of isolates, respectively. While we expected hvKP isolates to be overrepresented in this collection, we observed extensive diversity among hvKP pathogenicity loci, with strains of typical ST23 hvKP lineages carrying incomplete KpVP-1 virulence plasmids. This hvKP biomarker diversity is typically found in classical multidrug-resistant lineages that have acquired portions of the virulence plasmid. Phenotypic assays showed that hvKP biomarkers did not strictly predict hypermucoviscosity, capsule and siderophore production, or survival in serum. Loss of rmpA consistently eliminated hypermucoviscosity and reduced virulence in a murine pneumonia model, whereas aerobactin loss did not. In vivo studies demonstrated variations in virulence that could not be explained solely by differences in the number of hypervirulence-associated loci. These findings highlight the complexity of K. pneumoniae pathogenesis and demonstrate that while canonical biomarkers effectively distinguish hvKP from classical K. pneumoniae, they are insufficient to predict variation in virulence among hvKP strains. Our findings provide insight into the virulence spectrum of strains carrying incomplete plasmid configurations.IMPORTANCEK. pneumoniae poses a global health threat due to the convergence of antimicrobial resistance and hypervirulence. We identified substantial diversity in virulence plasmid content, including incomplete virulence plasmids within archetypal hvKP lineages, and showed that phenotypic and in vivo virulence traits cannot be fully explained by the presence or absence of individual hypervirulence-associated loci. While canonical biomarkers such as rmpA and iuc are widely used to distinguish hypervirulent strains, our analysis demonstrates that no single biomarker is sufficient to reliably predict pathogenic potential and that virulence depends on specific locus combinations and broader context. These findings highlight a critical gap in our understanding of hvKP pathogenesis, underscoring the need for more nuanced frameworks to evaluate virulence. This work has important implications for clinical diagnostics, surveillance, and risk assessment of emerging K. pneumoniae strains worldwide.
