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Bart Theelen - One of the best experts on this subject based on the ideXlab platform.
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The mitochondrial intergenic regions nad1-cob and cob-rps3 as molecular identification tools for pathogenic members of the genus Cryptococcus.
FEMS yeast research, 2019Co-Authors: Alexandra M. Kortsinoglou, Bart Theelen, Teun Boekhout, Artemis G. Korovesi, Ferry Hagen, Vassili N. KouvelisAbstract:Cryptococcus spp. are fungal species belonging to Tremellomycetes, Agaricomycotina, Basidiomycota, and several members are responsible for cryptococcosis, one of the most ubiquitous human mycoses. Affecting mainly immunosuppressed patients, but also immunocompetent ones, the members of this genus present a high level of genetic diversity. In this study, two mitochondrial intergenic regions, i.e. nad1-cob and cob-rps3, were tested for the intra- or interspecies discrimination and identification of strains and species of the genus Cryptococcus. Phylogenetic trees were constructed based on individual and concatenated sequences from representative pathogenic strains of the Cryptococcus neoformans/Cryptococcus gattii complex, representing serotypes and AFLP genotypes of all newly introduced species of this complex. Using both intergenic regions, as well as the concatenated dataset, the strains clustered in accordance with the new taxonomy. These results suggest that identification of Cryptococcus strains is possible by employing these mitochondrial intergenic regions using PCR amplification as a quick and effective method to elucidate genotypic and taxonomic differences. Thus, these regions may be applicable to a broad range of clinical studies, leading to a rapid recognition of the clinical profiles of patients.
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Phylogeny of tremellomycetous yeasts and related dimorphic and filamentous basidiomycetes reconstructed from multiple gene sequence analyses
Studies in Mycology, 2015Co-Authors: Qiming Wang, Marizeth Groenewald, Bart Theelen, Teun BoekhoutAbstract:The Tremellomycetes (Basidiomycota) contains a large number of unicellular and dimorphic fungi with stable free-living unicellular states in their life cycles. These fungi have been conventionally classified as basidiomycetous yeasts based on physiological and biochemical characteristics. Many currently recognised genera of these yeasts are mainly defined based on phenotypical characters and are highly polyphyletic. Here we reconstructed the phylogeny of the majority of described anamorphic and teleomorphic tremellomycetous yeasts using Bayesian inference, maximum likelihood, and neighbour-joining analyses based on the sequences of seven genes, including three rRNA genes, namely the small subunit of the ribosomal DNA (rDNA), D1/D2 domains of the large subunit rDNA, and the internal transcribed spacer regions (ITS 1 and 2) of rDNA including 5.8S rDNA; and four protein-coding genes, namely the two subunits of the RNA polymerase II (RPB1 and RPB2), the translation elongation factor 1-α (TEF1) and the mitochondrial gene cytochrome b (CYTB). With the consideration of morphological, physiological and chemotaxonomic characters and the congruence of phylogenies inferred from analyses using different algorithms based on different data sets consisting of the combined seven genes, the three rRNA genes, and the individual protein-coding genes, five major lineages corresponding to the orders Cystofilobasidiales, Filobasidiales, Holtermanniales, Tremellales, and Trichosporonales were resolved. A total of 45 strongly supported monophyletic clades with multiple species and 23 single species clades were recognised. This phylogenetic framework will be the basis for the proposal of an updated taxonomic system of tremellomycetous yeasts that will be compatible with the current taxonomic system of filamentous basidiomycetes accommodating the ‘one fungus, one name’ principle.
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Cold-adapted yeasts from Antarctica and the Italian Alps—description of three novel species: Mrakia robertii sp. nov.,
2013Co-Authors: Skye Robin, Skye Robin Thomas-hall, Pietro Buzzini, Bart Theelen, Kenneth Watson, Thomas-hall Benedetta Turchetti, Teun A Boekhout, Benedetta TurchettiAbstract:Ó The Author(s) 2009. This article is published with open access at Springerlink.com Abstract Worldwide glaciers are annually retreating due to global overheating and this phenomenon determines the potential lost of microbial diversity represented by psychrophilic microbial population sharing these peculiar habitats. In this context, yeast strains, all unable to grow above 20°C, consisting of 42 strains from Antarctic soil and 14 strains isolated from Alpine Glacier, were isolated and grouped together based on similar morphological and physiological characteristics. Sequences of the D1/D2 and ITS regions of the ribosomal DNA confirmed the previous analyses and demonstrated that the strains belong to unknown species. Three new species are proposed: Mrakia robertii sp. nov. (type strain CBS 8912), Mrakia blollopis sp. nov. (type strain CBS 8921) and a related anamorphic species Mrakiella niccombsii sp. nov. (type strain CBS 8917). Phylogenetic analysis of the ITS region revealed that the new proposed species were closely related to each other within the Mrakia clade in the order Cystofilobasidiales, class Tremellomycetes. The Mrakia clade now Communicated by A. Oren. Electronic supplementary material The online version of this article (doi:10.1007/s00792-009-0286-7) contains supplementary material, which is available to authorized users
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Cold-adapted yeasts from Antarctica and the Italian Alps—description of three novel species: Mrakia robertii sp. nov., Mrakia blollopis sp. nov. and Mrakiella niccombsii sp. nov.
Extremophiles, 2010Co-Authors: Skye Robin Thomas-hall, Benedetta Turchetti, Pietro Buzzini, Eva Branda, Bart Theelen, Teun Boekhout, Kenneth WatsonAbstract:Worldwide glaciers are annually retreating due to global overheating and this phenomenon determines the potential lost of microbial diversity represented by psychrophilic microbial population sharing these peculiar habitats. In this context, yeast strains, all unable to grow above 20°C, consisting of 42 strains from Antarctic soil and 14 strains isolated from Alpine Glacier, were isolated and grouped together based on similar morphological and physiological characteristics. Sequences of the D1/D2 and ITS regions of the ribosomal DNA confirmed the previous analyses and demonstrated that the strains belong to unknown species. Three new species are proposed: Mrakia robertii sp. nov. (type strain CBS 8912), Mrakia blollopis sp. nov. (type strain CBS 8921) and a related anamorphic species Mrakiella niccombsii sp. nov. (type strain CBS 8917). Phylogenetic analysis of the ITS region revealed that the new proposed species were closely related to each other within the Mrakia clade in the order Cystofilobasidiales, class Tremellomycetes. The Mrakia clade now contains 8 sub-clades. Teliospores were observed in all strains except CBS 8918 and for the Mrakiella niccombsii strains.
Teun Boekhout - One of the best experts on this subject based on the ideXlab platform.
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The mitochondrial intergenic regions nad1-cob and cob-rps3 as molecular identification tools for pathogenic members of the genus Cryptococcus.
FEMS yeast research, 2019Co-Authors: Alexandra M. Kortsinoglou, Bart Theelen, Teun Boekhout, Artemis G. Korovesi, Ferry Hagen, Vassili N. KouvelisAbstract:Cryptococcus spp. are fungal species belonging to Tremellomycetes, Agaricomycotina, Basidiomycota, and several members are responsible for cryptococcosis, one of the most ubiquitous human mycoses. Affecting mainly immunosuppressed patients, but also immunocompetent ones, the members of this genus present a high level of genetic diversity. In this study, two mitochondrial intergenic regions, i.e. nad1-cob and cob-rps3, were tested for the intra- or interspecies discrimination and identification of strains and species of the genus Cryptococcus. Phylogenetic trees were constructed based on individual and concatenated sequences from representative pathogenic strains of the Cryptococcus neoformans/Cryptococcus gattii complex, representing serotypes and AFLP genotypes of all newly introduced species of this complex. Using both intergenic regions, as well as the concatenated dataset, the strains clustered in accordance with the new taxonomy. These results suggest that identification of Cryptococcus strains is possible by employing these mitochondrial intergenic regions using PCR amplification as a quick and effective method to elucidate genotypic and taxonomic differences. Thus, these regions may be applicable to a broad range of clinical studies, leading to a rapid recognition of the clinical profiles of patients.
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Phylogeny of tremellomycetous yeasts and related dimorphic and filamentous basidiomycetes reconstructed from multiple gene sequence analyses
Studies in Mycology, 2015Co-Authors: Qiming Wang, Marizeth Groenewald, Bart Theelen, Teun BoekhoutAbstract:The Tremellomycetes (Basidiomycota) contains a large number of unicellular and dimorphic fungi with stable free-living unicellular states in their life cycles. These fungi have been conventionally classified as basidiomycetous yeasts based on physiological and biochemical characteristics. Many currently recognised genera of these yeasts are mainly defined based on phenotypical characters and are highly polyphyletic. Here we reconstructed the phylogeny of the majority of described anamorphic and teleomorphic tremellomycetous yeasts using Bayesian inference, maximum likelihood, and neighbour-joining analyses based on the sequences of seven genes, including three rRNA genes, namely the small subunit of the ribosomal DNA (rDNA), D1/D2 domains of the large subunit rDNA, and the internal transcribed spacer regions (ITS 1 and 2) of rDNA including 5.8S rDNA; and four protein-coding genes, namely the two subunits of the RNA polymerase II (RPB1 and RPB2), the translation elongation factor 1-α (TEF1) and the mitochondrial gene cytochrome b (CYTB). With the consideration of morphological, physiological and chemotaxonomic characters and the congruence of phylogenies inferred from analyses using different algorithms based on different data sets consisting of the combined seven genes, the three rRNA genes, and the individual protein-coding genes, five major lineages corresponding to the orders Cystofilobasidiales, Filobasidiales, Holtermanniales, Tremellales, and Trichosporonales were resolved. A total of 45 strongly supported monophyletic clades with multiple species and 23 single species clades were recognised. This phylogenetic framework will be the basis for the proposal of an updated taxonomic system of tremellomycetous yeasts that will be compatible with the current taxonomic system of filamentous basidiomycetes accommodating the ‘one fungus, one name’ principle.
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towards an integrated phylogenetic classification of the Tremellomycetes
Studies in Mycology, 2015Co-Authors: Xinzhan Liu, Ana M Millanes, Mats Wedin, Marizeth Groenewald, Q M Wang, Markus Goker, A V Kachalkin, H T Lumbsch, Andrey Yurkov, Teun BoekhoutAbstract:Families and genera assigned to Tremellomycetes have been mainly circumscribed by morphology and for the yeasts also by biochemical and physiological characteristics. This phenotype-based classification is largely in conflict with molecular phylogenetic analyses. Here a phylogenetic classification framework for the Tremellomycetes is proposed based on the results of phylogenetic analyses from a seven-genes dataset covering the majority of tremellomycetous yeasts and closely related filamentous taxa. Circumscriptions of the taxonomic units at the order, family and genus levels recognised were quantitatively assessed using the phylogenetic rank boundary optimisation (PRBO) and modified general mixed Yule coalescent (GMYC) tests. In addition, a comprehensive phylogenetic analysis on an expanded LSU rRNA (D1/D2 domains) gene sequence dataset covering as many as available teleomorphic and filamentous taxa within Tremellomycetes was performed to investigate the relationships between yeasts and filamentous taxa and to examine the stability of undersampled clades. Based on the results inferred from molecular data and morphological and physiochemical features, we propose an updated classification for the Tremellomycetes. We accept five orders, 17 families and 54 genera, including seven new families and 18 new genera. In addition, seven families and 17 genera are emended and one new species name and 185 new combinations are proposed. We propose to use the term pro tempore or pro tem. in abbreviation to indicate the species names that are temporarily maintained.
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ITS tree showing the phylogenetic relationship among the Tremellomycetes, with emphasis on the Bandoniozyma clade, obtained by neighbor-joining analysis using Mega 5.0.
2012Co-Authors: Patricia Valente, Melissa Fontes Landell, Teun Boekhout, Juliana Crestani, Fernando Carlos Pagnocca, Lara Durães Sette, Michel Rodrigo Zambrano Passarini, Carlos Augusto Rosa, Luciana R. Brandão, Raphael S. PimentaAbstract:Most species belong to the order Tremellales, with the exception of Cystofilobasidium capitatum (Cystofilobasidiales), Cryptococcus albidus (Filobasidiales), Trichosporum cutaneum (Trichosporonales), and the outgroup Farysizyma itapuensis (Ustilaginales). The numbers given on the branches are the frequencies with which a given branch appeared in 10,000 bootstrap replications. Bar, substitutions per nucleotide position.
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Cryptococcus randhawai sp. nov., a novel anamorphic basidiomycetous yeast isolated from tree trunk hollow of Ficus religiosa (peepal tree) from New Delhi, India
Antonie van Leeuwenhoek, 2010Co-Authors: Zia U. Khan, Jack W. Fell, Ferry Hagen, Suhail Ahmad, Tusharantak Kowshik, Rachel Chandy, Teun BoekhoutAbstract:A novel anamorphic Cryptococcus species is described, which was isolated in New Delhi (India) from decaying wood of a tree trunk hollow of Ficus religiosa . On the basis of sequence analysis of the D1/D2 domains of the 26S rRNA gene and the internally transcribed spacer (ITS)-1 and ITS-2 region sequences, the isolate belonged to the Cryptococcus albidus cluster (Filobasidiales, Tremellomycetes) and was closely related to Cryptococcus saitoi, Cryptococcus cerealis and Cryptococcus friedmannii with 98% sequence identity. Phenotypically, the species differed from C. saitoi with respect to growth temperature (up to 37^oC), presence of a thin capsule, ability to grow in the absence of vitamins, and inability to assimilate citrate and ethylamine. With respect to C. friedmannii , it differed in growth temperature, ability to assimilate lactose, raffinose, l -rhamnose, myo -inositol, and inability to utilize citrate. Furthermore, our isolate also differed from C. cerealis in growth temperature, presence of capsule and inability to assimilate l -sorbose. In view of the above phenotypic differences and unique rDNA sequences, we consider that our isolate represents a new species of Cryptococcus , and therefore, a new species, Cryptococcus randhawai is proposed for this taxon . The type strain J11/2002 has been deposited in the culture collection of the Centraalbureau voor Schimmelcultures (CBS10160) and CABI Biosciences (IMI 393306).
Kenneth Watson - One of the best experts on this subject based on the ideXlab platform.
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Cold-adapted yeasts from Antarctica and the Italian Alps—description of three novel species: Mrakia robertii sp. nov.,
2013Co-Authors: Skye Robin, Skye Robin Thomas-hall, Pietro Buzzini, Bart Theelen, Kenneth Watson, Thomas-hall Benedetta Turchetti, Teun A Boekhout, Benedetta TurchettiAbstract:Ó The Author(s) 2009. This article is published with open access at Springerlink.com Abstract Worldwide glaciers are annually retreating due to global overheating and this phenomenon determines the potential lost of microbial diversity represented by psychrophilic microbial population sharing these peculiar habitats. In this context, yeast strains, all unable to grow above 20°C, consisting of 42 strains from Antarctic soil and 14 strains isolated from Alpine Glacier, were isolated and grouped together based on similar morphological and physiological characteristics. Sequences of the D1/D2 and ITS regions of the ribosomal DNA confirmed the previous analyses and demonstrated that the strains belong to unknown species. Three new species are proposed: Mrakia robertii sp. nov. (type strain CBS 8912), Mrakia blollopis sp. nov. (type strain CBS 8921) and a related anamorphic species Mrakiella niccombsii sp. nov. (type strain CBS 8917). Phylogenetic analysis of the ITS region revealed that the new proposed species were closely related to each other within the Mrakia clade in the order Cystofilobasidiales, class Tremellomycetes. The Mrakia clade now Communicated by A. Oren. Electronic supplementary material The online version of this article (doi:10.1007/s00792-009-0286-7) contains supplementary material, which is available to authorized users
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Cold-adapted yeasts from Antarctica and the Italian Alps—description of three novel species: Mrakia robertii sp. nov., Mrakia blollopis sp. nov. and Mrakiella niccombsii sp. nov.
Extremophiles, 2010Co-Authors: Skye Robin Thomas-hall, Benedetta Turchetti, Pietro Buzzini, Eva Branda, Bart Theelen, Teun Boekhout, Kenneth WatsonAbstract:Worldwide glaciers are annually retreating due to global overheating and this phenomenon determines the potential lost of microbial diversity represented by psychrophilic microbial population sharing these peculiar habitats. In this context, yeast strains, all unable to grow above 20°C, consisting of 42 strains from Antarctic soil and 14 strains isolated from Alpine Glacier, were isolated and grouped together based on similar morphological and physiological characteristics. Sequences of the D1/D2 and ITS regions of the ribosomal DNA confirmed the previous analyses and demonstrated that the strains belong to unknown species. Three new species are proposed: Mrakia robertii sp. nov. (type strain CBS 8912), Mrakia blollopis sp. nov. (type strain CBS 8921) and a related anamorphic species Mrakiella niccombsii sp. nov. (type strain CBS 8917). Phylogenetic analysis of the ITS region revealed that the new proposed species were closely related to each other within the Mrakia clade in the order Cystofilobasidiales, class Tremellomycetes. The Mrakia clade now contains 8 sub-clades. Teliospores were observed in all strains except CBS 8918 and for the Mrakiella niccombsii strains.
Benedetta Turchetti - One of the best experts on this subject based on the ideXlab platform.
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Seasonal and altitudinal changes of culturable bacterial and yeast diversity in Alpine forest soils
Extremophiles, 2016Co-Authors: Luís França, Benedetta Turchetti, Pietro Buzzini, Ciro Sannino, Rosa MargesinAbstract:The effect of altitude and season on abundance and diversity of the culturable heterotrophic bacterial and yeast community was examined at four forest sites in the Italian Alps along an altitude gradient (545–2000 m). Independently of altitude, bacteria isolated at 0 °C (psychrophiles) were less numerous than those recovered at 20 °C. In autumn, psychrophilic bacterial population increased with altitude. The 1194 bacterial strains were primarily affiliated with the classes Alpha -, Beta -, Gammaproteobacteria , Spingobacteriia and Flavobacteriia. Fifty-seven of 112 operational taxonomic units represented potential novel species. Strains isolated at 20 °C had a higher diversity and showed similarities in taxa composition and abundance, regardless of altitude or season, while strains isolated at 0 °C showed differences in community composition at lower and higher altitudes. In contrast to bacteria, yeast diversity was season-dependent: site- and altitude-specific effects on yeast diversity were only detected in spring. Isolation temperature affected the relative proportions of yeast genera. Isolations recovered 719 strains, belonging to the classes Dothideomycetes , Saccharomycetes , Tremellomycetes and Mycrobotryomycetes. The presence of few dominant bacterial OTUs and yeast species indicated a resilient microbial population that is not affected by season or altitude. Soil nutrient contents influenced significantly abundance and diversity of culturable bacteria, but not of culturable yeasts.
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Cold-adapted yeasts from Antarctica and the Italian Alps—description of three novel species: Mrakia robertii sp. nov.,
2013Co-Authors: Skye Robin, Skye Robin Thomas-hall, Pietro Buzzini, Bart Theelen, Kenneth Watson, Thomas-hall Benedetta Turchetti, Teun A Boekhout, Benedetta TurchettiAbstract:Ó The Author(s) 2009. This article is published with open access at Springerlink.com Abstract Worldwide glaciers are annually retreating due to global overheating and this phenomenon determines the potential lost of microbial diversity represented by psychrophilic microbial population sharing these peculiar habitats. In this context, yeast strains, all unable to grow above 20°C, consisting of 42 strains from Antarctic soil and 14 strains isolated from Alpine Glacier, were isolated and grouped together based on similar morphological and physiological characteristics. Sequences of the D1/D2 and ITS regions of the ribosomal DNA confirmed the previous analyses and demonstrated that the strains belong to unknown species. Three new species are proposed: Mrakia robertii sp. nov. (type strain CBS 8912), Mrakia blollopis sp. nov. (type strain CBS 8921) and a related anamorphic species Mrakiella niccombsii sp. nov. (type strain CBS 8917). Phylogenetic analysis of the ITS region revealed that the new proposed species were closely related to each other within the Mrakia clade in the order Cystofilobasidiales, class Tremellomycetes. The Mrakia clade now Communicated by A. Oren. Electronic supplementary material The online version of this article (doi:10.1007/s00792-009-0286-7) contains supplementary material, which is available to authorized users
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Cold-adapted yeasts from Antarctica and the Italian Alps—description of three novel species: Mrakia robertii sp. nov., Mrakia blollopis sp. nov. and Mrakiella niccombsii sp. nov.
Extremophiles, 2010Co-Authors: Skye Robin Thomas-hall, Benedetta Turchetti, Pietro Buzzini, Eva Branda, Bart Theelen, Teun Boekhout, Kenneth WatsonAbstract:Worldwide glaciers are annually retreating due to global overheating and this phenomenon determines the potential lost of microbial diversity represented by psychrophilic microbial population sharing these peculiar habitats. In this context, yeast strains, all unable to grow above 20°C, consisting of 42 strains from Antarctic soil and 14 strains isolated from Alpine Glacier, were isolated and grouped together based on similar morphological and physiological characteristics. Sequences of the D1/D2 and ITS regions of the ribosomal DNA confirmed the previous analyses and demonstrated that the strains belong to unknown species. Three new species are proposed: Mrakia robertii sp. nov. (type strain CBS 8912), Mrakia blollopis sp. nov. (type strain CBS 8921) and a related anamorphic species Mrakiella niccombsii sp. nov. (type strain CBS 8917). Phylogenetic analysis of the ITS region revealed that the new proposed species were closely related to each other within the Mrakia clade in the order Cystofilobasidiales, class Tremellomycetes. The Mrakia clade now contains 8 sub-clades. Teliospores were observed in all strains except CBS 8918 and for the Mrakiella niccombsii strains.
Pietro Buzzini - One of the best experts on this subject based on the ideXlab platform.
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Seasonal and altitudinal changes of culturable bacterial and yeast diversity in Alpine forest soils
Extremophiles, 2016Co-Authors: Luís França, Benedetta Turchetti, Pietro Buzzini, Ciro Sannino, Rosa MargesinAbstract:The effect of altitude and season on abundance and diversity of the culturable heterotrophic bacterial and yeast community was examined at four forest sites in the Italian Alps along an altitude gradient (545–2000 m). Independently of altitude, bacteria isolated at 0 °C (psychrophiles) were less numerous than those recovered at 20 °C. In autumn, psychrophilic bacterial population increased with altitude. The 1194 bacterial strains were primarily affiliated with the classes Alpha -, Beta -, Gammaproteobacteria , Spingobacteriia and Flavobacteriia. Fifty-seven of 112 operational taxonomic units represented potential novel species. Strains isolated at 20 °C had a higher diversity and showed similarities in taxa composition and abundance, regardless of altitude or season, while strains isolated at 0 °C showed differences in community composition at lower and higher altitudes. In contrast to bacteria, yeast diversity was season-dependent: site- and altitude-specific effects on yeast diversity were only detected in spring. Isolation temperature affected the relative proportions of yeast genera. Isolations recovered 719 strains, belonging to the classes Dothideomycetes , Saccharomycetes , Tremellomycetes and Mycrobotryomycetes. The presence of few dominant bacterial OTUs and yeast species indicated a resilient microbial population that is not affected by season or altitude. Soil nutrient contents influenced significantly abundance and diversity of culturable bacteria, but not of culturable yeasts.
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Cold-adapted yeasts from Antarctica and the Italian Alps—description of three novel species: Mrakia robertii sp. nov.,
2013Co-Authors: Skye Robin, Skye Robin Thomas-hall, Pietro Buzzini, Bart Theelen, Kenneth Watson, Thomas-hall Benedetta Turchetti, Teun A Boekhout, Benedetta TurchettiAbstract:Ó The Author(s) 2009. This article is published with open access at Springerlink.com Abstract Worldwide glaciers are annually retreating due to global overheating and this phenomenon determines the potential lost of microbial diversity represented by psychrophilic microbial population sharing these peculiar habitats. In this context, yeast strains, all unable to grow above 20°C, consisting of 42 strains from Antarctic soil and 14 strains isolated from Alpine Glacier, were isolated and grouped together based on similar morphological and physiological characteristics. Sequences of the D1/D2 and ITS regions of the ribosomal DNA confirmed the previous analyses and demonstrated that the strains belong to unknown species. Three new species are proposed: Mrakia robertii sp. nov. (type strain CBS 8912), Mrakia blollopis sp. nov. (type strain CBS 8921) and a related anamorphic species Mrakiella niccombsii sp. nov. (type strain CBS 8917). Phylogenetic analysis of the ITS region revealed that the new proposed species were closely related to each other within the Mrakia clade in the order Cystofilobasidiales, class Tremellomycetes. The Mrakia clade now Communicated by A. Oren. Electronic supplementary material The online version of this article (doi:10.1007/s00792-009-0286-7) contains supplementary material, which is available to authorized users
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Cold-adapted yeasts from Antarctica and the Italian Alps—description of three novel species: Mrakia robertii sp. nov., Mrakia blollopis sp. nov. and Mrakiella niccombsii sp. nov.
Extremophiles, 2010Co-Authors: Skye Robin Thomas-hall, Benedetta Turchetti, Pietro Buzzini, Eva Branda, Bart Theelen, Teun Boekhout, Kenneth WatsonAbstract:Worldwide glaciers are annually retreating due to global overheating and this phenomenon determines the potential lost of microbial diversity represented by psychrophilic microbial population sharing these peculiar habitats. In this context, yeast strains, all unable to grow above 20°C, consisting of 42 strains from Antarctic soil and 14 strains isolated from Alpine Glacier, were isolated and grouped together based on similar morphological and physiological characteristics. Sequences of the D1/D2 and ITS regions of the ribosomal DNA confirmed the previous analyses and demonstrated that the strains belong to unknown species. Three new species are proposed: Mrakia robertii sp. nov. (type strain CBS 8912), Mrakia blollopis sp. nov. (type strain CBS 8921) and a related anamorphic species Mrakiella niccombsii sp. nov. (type strain CBS 8917). Phylogenetic analysis of the ITS region revealed that the new proposed species were closely related to each other within the Mrakia clade in the order Cystofilobasidiales, class Tremellomycetes. The Mrakia clade now contains 8 sub-clades. Teliospores were observed in all strains except CBS 8918 and for the Mrakiella niccombsii strains.
