Genomics and phylogenetic relationships of microsporidia and their relatives.

Microsporidia are intracellular parasites that all possess a unique infection apparatus involving a polar tube. Upon contact with a host cell, this tube forms the conduit through which the parasite enters the host. Infecting mostly animals, microsporidian species can be transmitted vertically or horizontally, and exert various effects on their hosts: infections range from being relatively benign to lethal. Microsporidian genomes possess highly divergent sequences and are often substantially reduced in size. Their divergent sequences and unique morphology created early challenges to our understanding of their phylogenetic position within the tree of eukaryotes. Over the last couple of decades, advances in both sequencing technology and phylogenetic methodology supported a clear relationship between microsporidia and fungi. However, the specifics of this relationship were muddied by the lack of known microsporidian relatives. With increased taxon discovery and the morphological and molecular characterization of microsporidia-like taxa, rozellids and aphelids, a better resolved picture is emerging. Here we review the history of microsporidian taxonomy and current status of genomics of microsporidia and their nearest relatives, with an aim to understand their morphological and metabolic differences, along with their evolutionary relationships.

Integrative approach to species delimitation in Rhizophydiales: Novel species of Angulomyces, Gorgonomyces, and Terramyces from northern Thailand.

The Chytridiomycota is a phylum of zoosporic eufungi that inhabit terrestrial, freshwater, and oceanic habitats. Within the phylum, the Rhizophydiales contains several monotypic families theorized to hold a diverse assemblage of fungi yet to be discovered and properly described. Based on morphology alone, many species in this order are difficult or impossible to identify. In this study, we isolated three chytrids from northern Thailand. Phylogenetic analyses placed the isolates in three monotypic genera within Rhizophydiales. Intrageneric genetic distances in the internal transcribed spacer (ITS) ranged between 1.5 and 8.5%. Angulomyces solicola sp. nov. is characterized by larger sporangia, spores, and fewer discharge papilla than A.argentinensis; Gorgonomyces thailandicus sp. nov. has larger zoospores and fewer discharge papillae in culture compared to G. haynaldii; Terramyces chiangraiensis sp. nov. produces larger sporangia than T. subangulosum. We delimited species of Angulomyces, Gorgonomyces and Terramyces using a tripartite approach that employed phylogeny, ITS genetic distances and Poisson tree processes (PTP). Results of these approaches suggest more than one species in each genus. This study contributes to the knowledge of chytrids, an understudied group in Thailand and worldwide.

Early-diverging fungal phyla: taxonomy, species concept, ecology, distribution, anthropogenic impact, and novel phylogenetic proposals.

The increasing number of new fungal species described from all over the world along with the use of genetics to define taxa, has dramatically changed the classification system of early-diverging fungi over the past several decades. The number of phyla established for non-Dikarya fungi has increased from 2 to 17. However, to date, both the classification and phylogeny of the basal fungi are still unresolved. In this article, we review the recent taxonomy of the basal fungi and re-evaluate the relationships among early-diverging lineages of fungal phyla. We also provide information on the ecology and distribution in Mucoromycota and highlight the impact of chytrids on amphibian populations. Species concepts in Chytridiomycota, Aphelidiomycota, Rozellomycota, Neocallimastigomycota are discussed in this paper. To preserve the current application of the genus Nephridiophaga (Chytridiomycota: Nephridiophagales), a new type species, Nephridiophaga blattellae, is proposed.

Diversity of Rhizophydiales (Chytridiomycota) in Thailand: unveiling the hidden gems of the Kingdom.

Chytrids, often overshadowed by their other fungal counterparts, take center stage as we unravel the mysteries surrounding new species within Rhizophydiales and explore their unique characteristics. In the broader spectrum of chytrids, their significance lies not only in their roles as decomposers but also as key players in nutrient cycling within aquatic ecosystems as parasites and saprobes. Baited soil and aquatic samples collected from various provinces of Thailand, yielded new species of the Rhizophydiales (Chytridiomycota), some of which expanded previously single species genera. Our investigation incorporated a combination of morphological and phylogenetic approaches, enabling us to identify these isolates as distinct taxa. The novel isolates possess distinguishing features, such as variations in size and shape of the sporangium and zoospores, that somewhat differentiate them from described taxa. To confirm the novelty of the species, we employed robust phylogenetic analyses using maximum likelihood and bayesian methods. The results provided strong support for the presence of eight distinct lineages within the Rhizophydiales, representing our newly discovered species. Furthermore, we employed Poisson Tree Processes to infer putative species boundaries and supplement evidence for the establishment of our new Rhizophydiales species. By meticulously exploring their morphological characteristics and genetic makeup, we expand the known catalogue of fungal diversity by describing Alphamyces thailandicus, Angulomyces ubonensis, Gorgonomyces aquaticus, G. chiangraiensis, G. limnicus, Pateramyces pingflumenensis, Terramyces aquatica, and T. flumenensis and also provide valuable insights into the intricacies of this order. This newfound knowledge not only enriches our understanding of Rhizophydiales but also contributes significantly to the broader field of mycology, addressing a critical gap in the documentation of fungal species. The identification and characterization of these eight novel species mark a noteworthy stride towards a more comprehensive comprehension of fungal ecosystems and their vital role.

Candida nivariensis, an emerging fungus causing peritonitis in a patient receiving peritoneal dialysis.

Fungal peritonitis (FP) is usually associated with poor patient outcomes and is mostly caused by non-albicans Candida species. We present a Candida nivariensis-associated peritonitis in a 68-year-old woman with end-stage kidney disease on peritoneal dialysis (PD). Biochemical profiling of the cultured yeast of the effluent sample did not adequately identify the yeast. Hence, molecular phylogeny and Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) mass spectroscopy were employed which correctly identified the causative species, C. nivariensis. PD catheter was removed and oral fluconazole was promptly started according to the 2022 International Society for PD (ISPD) Peritonitis Guidelines. However, the patient achieved only a partial clinical response and eventually died. The susceptibility test showed that the pathogen was susceptible to amphotericin B and voriconazole but resistant to other triazoles. This report underlines the importance of identifying the species, though rarely reported, and the drug susceptibility of the organism.

Peritoneal dialysis-associated peritonitis caused by Exophiala spinifera: A case report and review of literature.

Exophiala spinifera is a black ascomycetous yeast and is responsible for phaeohyphomycosis. We provide the first case report of peritoneal dialysis (PD)-associated peritonitis in a female patient with progressive impairment of visual capacity. The infection was caused by a cutaneous infection of her hands. The patient responded well with PD catheter removal and 2-week antifungal medication. This case emphasizes the importance of hand hygiene and regular eye evaluation in preventing environment-bound infection in patients on PD. 2012 Elsevier Ltd. All rights reserved.

Novel Mucor species (Mucoromycetes, Mucoraceae) from northern Thailand.

Mucor species are common fast-growing fungi found in soil. Two new species of Mucor and one new geographical record of M.nederlandicus were collected from northern Thailand and are described in this study. Evidence from morphophysiological data and phylogenetic analysis supports the introduction of the new taxa. Phylogenetic analysis based on the internal transcribed spacer (ITS) and large subunit of the nuclear ribosomal RNA (LSU) data showed that the new isolates cluster distinctly from other Mucor species with high or maximum bootstrap support. Mucoraseptatophorus is characterized by aseptate sporangiophores, globose columella, resistant and deliquescent sporangia, has sympodial, and monopodial branches and shows growth at 37 °C. It also differs from M.irregularis in having smaller sporangiospores, and larger sporangia. Mucorchiangraiensis has subglobose or slightly elongated globose columella, produces hyaline sporangiospores, and resistant and deliquescent sporangia. Furthermore, this species has wider sporangiophore, smaller sporangia and lower growth than M.nederlandicus. A detailed description of the species and illustrations are provided for the novel species.

The first human report of Hyphopichia burtonii, initially misdiagnosed as sterile peritonitis in a patient on peritoneal dialysis.

This is the first human infection caused by Hyphopichia burtonii, resulting in peritonitis in a patient on peritoneal dialysis initially diagnosed as sterile peritonitis, resulting in delayed diagnosis and treatment. This pathogen posed a challenging diagnosis, causing low-grade peritonitis and difficulty to culture with standard bacterial broth. Moreover, automated platforms for pathogenic yeast identification could not specify the species, but broad-range PCR targeting rDNA followed by DNA sequencing successfully solved the etiology.