Mycobiology最新文献

In this study, we aimed to analyze the annual, age- and sex-specific frequencies and antifungal resistance rates of Candida albicans infections over an 11-year period (2013 - 2023) at a university hospital in South Chungcheong Province, South Korea. A total of 476 cases identified as C. albicans from 260,769 blood cultures were analyzed retrospectively. The annual number of C. albicans isolates increased by 161.1% in 2019 and 136.7% in 2022 compared with that in the previous year. The mean age of patients from whom C. albicans was isolated was 65.8 years, with 51.8% patients being aged 60-79 years. The number of isolates was higher in male patients than in female patients (male-to-female ratio: 1.4:1). Of the isolates, 6.6% were resistant to flucytosine and 4.5% were resistant to voriconazole, whereas all isolates were susceptible to caspofungin and micafungin. Overall, this study provides vital foundational data for tertiary general hospitals in the Chungcheong region and for developing national infection management strategies, thereby providing a valuable basis for future in-depth studies.

The ability of Candida albicans to switch among yeast, hyphal, and pseudohyphal forms underlies its adaptability and pathogenicity. While cAMP-dependent signaling has long been considered central to hyphal growth, recent multi-omics studies show that cAMP-independent mechanisms also drive morphological changes. Basal PKA activity, cyclin-dependent kinases (e.g., Cdc28), and other regulators can promote shape-shifting even without classical cAMP pathways. In addition, N-acetylglucosamine (GlcNAc) acts as a potent signal that induces hyphal growth independently of its metabolic role, directly connecting environmental cues to morphological states. By integrating transcriptomic, proteomic, and phosphoproteomic data, this review exposes the intricate networks controlling C. albicans morphogenesis. A clearer understanding of these complex regulatory circuits lays the groundwork for future studies that employ advanced multi-omics analyses. Such approaches will help elucidate how these pathways converge, how they respond to changing environments, and how they might be harnessed or disrupted to influence fungal behavior.

This study was conducted to investigate the growth characteristics and morphology of Pleurotus ostreatus mycelium during co-cultivation with Pseudomonas putida. For selection of the most effective Pseudomonas species in coculture, Three strains of Pseudomonas putida and one strain of Pseudomonas fluorescens were co-cultured with heuktari, one of the varieties of P. ostreatus, on NPDA agar medium to observe the growth pattern of mycelium. It was found that the microorganism affecting mycelium growth during co-cultivation was P. putida KACC 10275, and co-cultivation of these two species resulted in enhanced mycelium growth on both NPDA and sawdust agar media. Furthermore, while primordium formation and fruit body development did not occur on plates inoculated only with heuktari, fruit bodies were observed only on plates where heuktari and P. putida were co-cultured, as confirmed by cultivation in the growth chamber for the same duration.

Inocybe crenata sp. nov. (subsec. Geophyllinae, sect. Tardae) has been described from conifer dominated forests of Pakistan. Inocybe crenata differs from other related species by having a pale-yellow pileus with crenate margins and a bumpy or cracked center, with a fibrillose stipe. Phylogenetic analysis based on nuclear ribosomal large subunit (LSU) and internal transcribed spacer (nrITS) sequence data supported the identity of Inocybe crenate as a distinct taxon. A detailed description of this novel species is provided.

Small galls and white blisters with cup-like fungal structures were observed on the leaves of Machilus thunbergii (Lauraceae), a tree species native to East Asia. Based on its distinctive symptoms and aster-shaped spores, the causal agent was identified as Asteroconium saccardoi. Despite its unique characteristics, the genus Asteroconium remains taxonomically unresolved (incertae sedis) within the phylum Ascomycota due to the absence of both sequence data and available culture. The present study successfully obtained ITS and LSU rDNA sequences from its fresh spore masses formed on M. thunbergii. Phylogenetic analysis revealed that A. saccardoi belongs to the order Exobasidiales under Basidiomycota. Detailed morphological characteristics of basidia and basidiospores were documented, providing comprehensive insights into the taxonomy and phylogeny of Asteroconium within Exobasidiales.

The genus Preussia is widely distributed and includes species with ecological and biotechnological importance. In this study, morphological and phylogenetic analyses of the ITS and LSU rDNA sequences revealed two novel species, P. jejuensis sp. nov. and P. koreensis sp. nov., as well as one previously unrecorded species in Korea, P. isomera, from horse dung collected in Seopjikoji, Jeju Island, Republic of Korea. P. jejuensis sp. nov. is unique in producing conidia from conidiomata instead of teleomorphic structures, a feature not observed in any other known species of the Preussia genus. P. koreensis sp. nov. is morphologically distinguished by the absence of a neck, a smaller ascocarp diameter, smaller asci, and larger ascospores. In the phylogenetic analysis, P. jejuensis sp. nov. was closely related to P. isomera and S. minimoides, while P. koreensis sp. nov. was closely related to P. arizonica, P. persica, and S. minima. However, P. jejuensis sp. nov. and P. koreensis sp. nov. were clearly distinguished from their related species. This study expands the understanding of the biodiversity of coprophilous fungi and its distribution in Jeju Island, a region where horse breeding has been practiced for centuries, emphasizing the ecological importance of dung as a fungal habitat.

An improved sporulation method for Pythium aphanidermatum on 10% V₈-juice agar was developed to generate substantial quantities of zoospores. We conducted experiments using a 4 × 4 factorial design to evaluate the effects of temperature (20, 25, 30, and 35 °C) and incubation time (2, 3, 4, and 5 days) on zoospore production from isolates HSv05 and KACC 48066. The results indicated that a temperature of 30 °C consistently yielded the highest numbers of zoospores across all incubation periods. Applying the same temperature (30 °C) and all incubation periods to other isolates (CCp03, CCp04, CCp05, HSv10, and KACC 40156) also resulted in higher numbers of zoospores regardless of incubation times compared with that under the control condition (25 °C and 2 days). Further virulence tests of isolate HSv05 revealed that high concentrations of zoospores (5 × 10² - 10⁵ zoospores/ml) induced severe rot symptoms; however, a low concentration of 10² zoospores/ml produced only considerably weak symptoms on inoculated potato tubers. No symptoms appeared in tubers inoculated with 0 (uninoculated control) or 10¹ zoospores/ml. These findings suggest that our sporulation method can help obtain adequate zoospores for various basic and applied studies, including pathogen identification, virulence assessment, resistance resource screening, and control strategy development.

During an investigation of Korean Ascomycetes in 2023, we found two undescribed species from South Korea. We analyzed them using a combined approach, including morphological and phylogenetic analyses of the rDNA regions (internal transcribed spacer and large subunit). The two species were identified to belong to the genus Geoglossum; the species G. simile and a new species named G. subdifforme sp. nov. The phylogenetic tree constructed using the ITS region showed that G. subdifforme is closely related to G. difforme. These species are distinguishable by certain morphological characteristics, particularly the size and septae of ascospores. Morphologically, G. simile is related to G. glabrum, but it is distinguishable by the morphological characteristics of paraphyses as well as ITS sequences. In this study, the descriptions, photographs, and phylogenetic relationships of these Geoglossum species are presented.

In this study, we aimed to develop simple sequence repeat (SSR) markers for evaluating resources in Armillaria ostoyae and examine their transferability to Armillaria gallica, related species. SSR markers were developed using the released A. ostoyae whole-genome sequence (GenBank assembly accession: GCA_900157425.1). The SSR regions were analyzed using the MISA (MIcroSAtellite identification tool) program. A total of 2319 SSR loci consisting of 922 (39.76%) mononucleotide, 763 (32.90%) trinucleotide, and 517 (22.29%) dinucleotide motifs were identified. Marker design involved an arbitrary choice of 150 SSR loci, considering motif abundance. A total of 22 strains of A. ostoyae were analyzed using the developed markers, and 105 markers were successfully amplified. The mean values of major allele frequency, number of alleles, expected heterozygosity, observed heterozygosity, and polymorphism information content (PIC) values were approximately 5.89, 5.4, 0.541, 0.255, and 0.504, respectively. A. gallica was analyzed, and 52 markers (49.5%) were successfully amplified to evaluate the transferability of the developed SSR markers. When these markers were used, the mean values of major allele frequency, number of alleles, expected heterozygosity, observed heterozygosity, and PIC were calculated to be approximately 0.615, 4.3, 0.517, 0.133, and 0.502, respectively. In conclusion, SSR markers were developed using the genome of A. ostoyae, and some of these markers exhibited transferability to A. gallica. These results can be used for resource evaluation of A. ostoyae and A. gallica.

Ambrosia fungi are well-known for their symbiotic interactions with ambrosia beetles, acting as a sole food source of larvae and adult beetles. As a first step to reveal these interactions, extensive survey on the fungal symbionts of ambrosia beetles dwelling in Korea. Eight fungal species isolated from 15 ambrosia beetle species were not known for their presence in Korea. Seven of these belonged to two orders of Ascomycota; Microascales (Ambrosiella beaveri, A. catenulate, and A. roeperi) and Ophiostomatales (Leptographium verrucosum, Raffaelea cyclorhipidii, R. subfusca, and Sporothrix eucastaneae) and one to Polyporales of Basidiomycota (Irpex subulatus). This is the first report of these species in Korea with taxonomic descriptions.