Nejvíce citovaný článek - PubMed ID 28551852
Cultivable microscopic fungi from an underground chemosynthesis-based ecosystem: a preliminary study
Aspergillus series Versicolores members occur in a wide range of environments and substrates such as indoor environments, food, clinical materials, soil, caves, marine or hypersaline ecosystems. The taxonomy of the series has undergone numerous re-arrangements including a drastic reduction in the number of species and subsequent recovery to 17 species in the last decade. The identification to species level is however problematic or impossible in some isolates even using DNA sequencing or MALDI-TOF mass spectrometry indicating a problem in the definition of species boundaries. To revise the species limits, we assembled a large dataset of 518 strains. From these, a total of 213 strains were selected for the final analysis according to their calmodulin (CaM) genotype, substrate and geography. This set was used for phylogenetic analysis based on five loci (benA, CaM, RPB2, Mcm7, Tsr1). Apart from the classical phylogenetic methods, we used multispecies coalescence (MSC) model-based methods, including one multilocus method (STACEY) and five single-locus methods (GMYC, bGMYC, PTP, bPTP, ABGD). Almost all species delimitation methods suggested a broad species concept with only four species consistently supported. We also demonstrated that the currently applied concept of species is not sustainable as there are incongruences between single-gene phylogenies resulting in different species identifications when using different gene regions. Morphological and physiological data showed overall lack of good, taxonomically informative characters, which could be used for identification of such a large number of existing species. The characters expressed either low variability across species or significant intraspecific variability exceeding interspecific variability. Based on the above-mentioned results, we reduce series Versicolores to four species, namely A. versicolor, A. creber, A. sydowii and A. subversicolor, and the remaining species are synonymized with either A. versicolor or A. creber. The revised descriptions of the four accepted species are provided. They can all be identified by any of the five genes used in this study. Despite the large reduction in species number, identification based on phenotypic characters remains challenging, because the variation in phenotypic characters is high and overlapping among species, especially between A. versicolor and A. creber. Similar to the 17 narrowly defined species, the four broadly defined species do not have a specific ecology and are distributed worldwide. We expect that the application of comparable methodology with extensive sampling could lead to a similar reduction in the number of cryptic species in other extensively studied Aspergillus species complexes and other fungal genera. Citation: Sklenář F, Glässnerová K, Jurjević Ž, Houbraken J, Samson RA, Visagie CM, Yilmaz N, Gené J, Cano J, Chen AJ, Nováková A, Yaguchi T, Kolařík M, Hubka V (2022). Taxonomy of Aspergillus series Versicolores: species reduction and lessons learned about intraspecific variability. Studies in Mycology 102 : 53-93. doi: 10.3114/sim.2022.102.02.
- Klíčová slova
- Aspergillus creber, Aspergillus sydowii, Aspergillus versicolor, indoor fungi, multispecies coalescent model, osmotolerance, species delimitation, sterigmatocystin,
- Publikační typ
- časopisecké články MeSH
Aspergillus section Candidi encompasses white- or yellow-sporulating species mostly isolated from indoor and cave environments, food, feed, clinical material, soil and dung. Their identification is non-trivial due to largely uniform morphology. This study aims to re-evaluate the species boundaries in the section Candidi and present an overview of all existing species along with information on their ecology. For the analyses, we assembled a set of 113 strains with diverse origin. For the molecular analyses, we used DNA sequences of three house-keeping genes (benA, CaM and RPB2) and employed species delimitation methods based on a multispecies coalescent model. Classical phylogenetic methods and genealogical concordance phylogenetic species recognition (GCPSR) approaches were used for comparison. Phenotypic studies involved comparisons of macromorphology on four cultivation media, seven micromorphological characters and growth at temperatures ranging from 10 to 45 °C. Based on the integrative approach comprising four criteria (phylogenetic and phenotypic), all currently accepted species gained support, while two new species are proposed (A. magnus and A. tenebricus). In addition, we proposed the new name A. neotritici to replace an invalidly described A. tritici. The revised section Candidi now encompasses nine species, some of which manifest a high level of intraspecific genetic and/or phenotypic variability (e.g., A. subalbidus and A. campestris) while others are more uniform (e.g., A. candidus or A. pragensis). The growth rates on different media and at different temperatures, colony colours, production of soluble pigments, stipe dimensions and vesicle diameters contributed the most to the phenotypic species differentiation. Taxonomic novelties: New species: Aspergillus magnus Glässnerová & Hubka; Aspergillus neotritici Glässnerová & Hubka; Aspergillus tenebricus Houbraken, Glässnerová & Hubka. Citation: Glässnerová K, Sklenář F, Jurjević Ž, Houbraken J, Yaguchi T, Visagie CM, Gené J, Siqueira JPZ, Kubátová A, Kolařík M, Hubka V (2022). A monograph of Aspergillus section Candidi. Studies in Mycology 102: 1-51. doi: 10.3114/sim.2022.102.01.
- Klíčová slova
- Aspergillus candidus, Aspergillus tritici, genealogical concordance, integrative taxonomy, intraspecific variability, multispecies coalescent model,
- Publikační typ
- časopisecké články MeSH
Castañar Cave is a clear example of an oligotrophic ecosystem with high hygrothermal stability both seasonal and interannual and the particularity of registering extraordinary levels of environmental radiation. These environmental conditions make the cave an ideal laboratory to evaluate both the responses of the subterranean environment to sudden changes in the matter and energy fluxes with the exterior and also any impact derived from its use as a tourist resource under a very restrictive access regime. In 2008, a fungal outbreak provoked by a vomit contaminated the sediments which were removed and subsequently treated with hydrogen peroxide. Fungal surveys were carried out in 2008 and 2009. The visits were resumed in 2014. Here, 12 years after the outbreak, we present an exhaustive study on the cave sediments in order to know the distribution of the different fungal taxa, as well as the prevalence and spatio-temporal evolution of the fungi caused by the vomit over the years under the conditions of relative isolation and high radiation that characterize this cave.
- Klíčová slova
- Ascomycota, Basidiomycota, Castañar Cave, fungal outbreak, ionizing radiation, radon,
- Publikační typ
- časopisecké články MeSH
Since the last revision in 2015, the taxonomy of section Flavipedes evolved rapidly along with the availability of new species delimitation techniques. This study aims to re-evaluate the species boundaries of section Flavipedes members using modern delimitation methods applied to an extended set of strains (n = 90) collected from various environments. The analysis used DNA sequences of three house-keeping genes (benA, CaM, RPB2) and consisted of two steps: application of several single-locus (GMYC, bGMYC, PTP, bPTP) and multi-locus (STACEY) species delimitation methods to sort the isolates into putative species, which were subsequently validated using DELINEATE software that was applied for the first time in fungal taxonomy. As a result, four new species are introduced, i.e. A. alboluteus, A. alboviridis, A. inusitatus and A. lanuginosus, and A. capensis is synonymized with A. iizukae. Phenotypic analyses were performed for the new species and their relatives, and the results showed that the growth parameters at different temperatures and colonies characteristics were useful for differentiation of these taxa. The revised section harbors 18 species, most of them are known from soil. However, the most common species from the section are ecologically diverse, occurring in the indoor environment (six species), clinical samples (five species), food and feed (four species), droppings (four species) and other less common substrates/environments. Due to the occurrence of section Flavipedes species in the clinical material/hospital environment, we also evaluated the susceptibility of 67 strains to six antifungals (amphotericin B, itraconazole, posaconazole, voriconazole, isavuconazole, terbinafine) using the reference EUCAST method. These results showed some potentially clinically relevant differences in susceptibility between species. For example, MICs higher than those observed for A. fumigatus wild-type were found for both triazoles and amphotericin B for A. ardalensis, A. iizukae, and A. spelaeus whereas A. lanuginosus, A. luppiae, A. movilensis, A. neoflavipes, A. olivimuriae and A. suttoniae were comparable to or more susceptible as A. fumigatus. Finally, terbinafine was in vitro active against all species except A. alboviridis.
- Klíčová slova
- Antifungal susceptibility testing, Aspergillus alboluteus F. Sklenar, Jurjević, Ezekiel, Houbraken & Hubka, Aspergillus alboviridis J.P.Z. Siqueira, Gené, F. Sklenar & Hubka, Aspergillus flavipes, Aspergillus inusitatus F. Sklenar, C. Silva Pereira, Houbraken & Hubka, Aspergillus lanuginosus F. Sklenar & Hubka, Clinical fungi, Indoor fungi, Multigene phylogeny, Soil-borne fungi, Species delimitation,
- Publikační typ
- časopisecké články MeSH
Different strains of the saprophytic yeast-like fungus Aureobasidium pullulans (Ascomycota: Dothideales) exhibit different biochemical characteristics, while their ubiquitous occurrence across diverse habitats and environmental conditions makes them an easily accessible source for biotechnological exploitation. They are useful in agricultural and industrial applications. Their antagonistic activities against postharvest pathogens make them suitable bioagents for the postharvest preservation of fruits and vegetables, while they possess antimicrobial activities against bacteria and fungi. Additionally, A. pullulans appears to be a potent source of single-cell protein. Many strains of A. pullulans harbor a wide range of industrially important enzymes, while the trademark exopolysaccharide pullulan that they produce has been extensively studied and is currently used in many applications. They also produce poly (β-L-malic acid), heavy oil liamocins, siderophore, and aubasidan-like β-glucan which are of interest for future applications. Ongoing studies suggest that A. pullulans holds many more interesting properties capable of further potential biotechnological applications.
- Klíčová slova
- Antimicrobial potentials, Aureobasidium pullulans, Enzymes, Postharvest control, Pullulan,
- MeSH
- Ascomycota enzymologie genetika metabolismus MeSH
- fungální proteiny genetika metabolismus MeSH
- glukany metabolismus MeSH
- průmyslová mikrobiologie * MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Názvy látek
- fungální proteiny MeSH
- glukany MeSH
- pullulan MeSH Prohlížeč