Exploiting the Advantages of Molecular Tools for the Monitoring of Fungal Indoor Air Contamination: First Detection of Exophiala jeanselmei in Indoor Air of Air-Conditioned Offices

Exophiala zingiberis sp. nov., a novel cellulase-producing black yeast-like fungi isolated from ginger in India

The genus Exophiala, known for its melanized, yeast-like appearance, includes a diverse group of fungi with significant implications across various fields. An isolate representing a novel species was identified within this genus from a ginger tuber from India, based on morphological characteristics and molecular phylogenetic analysis. Phylogenetic analysis of the D1/D2 domain of the 26S LSU rRNA gene, SSU rRNA gene and the internal transcribed spacer (ITS) region confirmed this strain as a new species. It was named Exophiala zingiberis sp. nov. (MycoBank no. MB 855415), with MCC 9960T designated as the holotype and PYCC 9834 as the isotype. Exophiala zingiberis was positioned as a sister species to a clade that includes Exophiala castellanii, Exophiala mali and three additional species. Phylogenetic analysis indicates that while E. zingiberis shares a common ancestor with these species, it is genetically distinct, underscoring its novel status. The type strain of this novel species differs from Exophiala yuxiensis YMF1.07354T, the most closely related species, by 19 nucleotide substitutions (3.6% sequence variation) in the D1/D2 region (549 bp compared) and 104 nucleotide substitutions and 44 gaps (27.1% sequence variation) in the ITS region (546 bp compared).

Method for detection of pathogenic bacteria from indoor air microbiome samples using high-throughput amplicon sequencing

The exposure of the air microbiome in indoor air posed a detrimental health effect to the building occupants compared to the outdoor air. Indoor air in hospitals has been identified as a reservoir for various pathogenic microbes. The conventional culture-dependent method has been widely used to access the microbial community in the air. However, it has limited capability in enumerating the complex air microbiome communities, as some of the air microbiomes are uncultivable, slow-growers, and require specific media for cultivation. Here, we utilized a culture-independent method via amplicon sequencing to target the V3 region of 16S rRNA from the pool of total genomic DNA extracted from the dust samples taken from hospital interiors. This method will help occupational health practitioners, researchers, and health authorities to efficiently and comprehensively monitor the presence of harmful air microbiome thus take appropriate action in controlling and minimizing the health risks to the hospital occupants. Key features;•Culture-independent methods offer fast, comprehensive, and unbias profiles of pathogenic and non-pathogenic bacteria from the air microbiomes.•Unlike the culture-dependent method, amplicon sequencing allows bacteria identification to the lowest taxonomy levels.

Exploring diversity rock-inhabiting fungi from northern Thailand: a new genus and three new species belonged to the family Herpotrichiellaceae

Members of the family Herpotrichiellaceae are distributed worldwide and can be found in various habitats including on insects, plants, rocks, and in the soil. They are also known to be opportunistic human pathogens. In this study, 12 strains of rock-inhabiting fungi that belong to Herpotrichiellaceae were isolated from rock samples collected from forests located in Lamphun and Sukhothai provinces of northern Thailand during the period from 2021 to 2022. On the basis of the morphological characteristics, growth temperature, and multi-gene phylogenetic analyses of a combination of the internal transcribed spacer, the large subunit, and the small subunit of ribosomal RNA, beta tubulin and the translation elongation factor 1-a genes, the new genus, Petriomyces gen. nov., has been established to accommodate the single species, Pe. obovoidisporus sp. nov. In addition, three new species of Cladophialophora have also been introduced, namely, Cl. rupestricola, Cl. sribuabanensis, and Cl. thailandensis. Descriptions, illustrations, and a phylogenetic trees indicating the placement of these new taxa are provided. Here, we provide updates and discussions on the phylogenetic placement of other fungal genera within Herpotrichiellaceae.

Species Diversity, Distribution, and Phylogeny of Exophiala with the Addition of Four New Species from Thailand

The genus Exophiala is an anamorphic ascomycete fungus in the family Herpotrichiellaceae of the order Chaetothyriales. Exophiala species have been classified as polymorphic black yeast-like fungi. Prior to this study, 63 species had been validated, published, and accepted into this genus. Exophiala species are known to be distributed worldwide and have been isolated in various habitats around the world. Several Exophiala species have been identified as potential agents of human and animal mycoses. However, in some studies, Exophiala species have been used in agriculture and biotechnological applications. Here, we provide a brief review of the diversity, distribution, and taxonomy of Exophiala through an overview of the recently published literature. Moreover, four new Exophiala species were isolated from rocks that were collected from natural forests located in northern Thailand. Herein, we introduce these species as E. lamphunensis, E. lapidea, E. saxicola, and E. siamensis. The identification of these species was based on a combination of morphological characteristics and molecular analyses. Multi-gene phylogenetic analyses of a combination of the internal transcribed spacer (ITS) and small subunit (nrSSU) of ribosomal DNA, along with the translation elongation factor (tef), partial β-tubulin (tub), and actin (act) genes support that these four new species are distinct from previously known species of Exophiala. A full description, illustrations, and a phylogenetic tree showing the position of four new species are provided.