Publications by authors named "Marizeth Groenewald"

48 Publications

Intraspecific nucleotide divergence in Saccharomycodes ludwigii, and proposal of Saccharomycodes pseudoludwigii sp. nov, a new apiculate yeast isolated from China.

Antonie Van Leeuwenhoek 2021 Feb 23. Epub 2021 Feb 23.

Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands.

The six synonyms currently accepted under Saccharomycodes ludwigii were investigated for by phenotypic properties, however, the sequence diversity of the rRNA and protein coding genes have not yet been determined. Nine strains including the type strains of synonyms of S. ludwigii deposited in the CBS yeast collection, Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands, were analyzed using a multi-locus sequence analysis (MLSA) approach that included sequences of 18S ribosomal RNA (rRNA), the D1/D2 domains of the 26S rRNA, the ITS region (including the 5.8S rRNA) and fragments of genes encoding the largest subunit of the RNA polymerase II (RPB1 and RPB2) and translation elongation factor 1-α (TEF1). Our results showed that the nine strains have identical D1/D2, 18S and RPB2 sequences and similar ITS, RPB1 and TEF1 sequences, which indicated that they are conspecific. In addition, a novel species of Saccharomycodes, S. pseudoludwigii sp. nov. (type CGMCC 2.4526) that was isolated from fruit and tree bark in China, is proposed. The MycoBank number of this new species is MB 811,650.
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http://dx.doi.org/10.1007/s10482-021-01540-8DOI Listing
February 2021

A genome-scale phylogeny of the kingdom Fungi.

Curr Biol 2021 Feb 12. Epub 2021 Feb 12.

Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA. Electronic address:

Phylogenomic studies using genome-scale amounts of data have greatly improved understanding of the tree of life. Despite the diversity, ecological significance, and biomedical and industrial importance of fungi, evolutionary relationships among several major lineages remain poorly resolved, especially those near the base of the fungal phylogeny. To examine poorly resolved relationships and assess progress toward a genome-scale phylogeny of the fungal kingdom, we compiled a phylogenomic data matrix of 290 genes from the genomes of 1,644 species that includes representatives from most major fungal lineages. We also compiled 11 data matrices by subsampling genes or taxa from the full data matrix based on filtering criteria previously shown to improve phylogenomic inference. Analyses of these 12 data matrices using concatenation- and coalescent-based approaches yielded a robust phylogeny of the fungal kingdom, in which ∼85% of internal branches were congruent across data matrices and approaches used. We found support for several historically poorly resolved relationships as well as evidence for polytomies likely stemming from episodes of ancient diversification. By examining the relative evolutionary divergence of taxonomic groups of equivalent rank, we found that fungal taxonomy is broadly aligned with both genome sequence divergence and divergence time but also identified lineages where current taxonomic circumscription does not reflect their levels of evolutionary divergence. Our results provide a robust phylogenomic framework to explore the tempo and mode of fungal evolution and offer directions for future fungal phylogenetic and taxonomic studies.
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http://dx.doi.org/10.1016/j.cub.2021.01.074DOI Listing
February 2021

Genome-scale phylogeny and contrasting modes of genome evolution in the fungal phylum Ascomycota.

Sci Adv 2020 Nov 4;6(45). Epub 2020 Nov 4.

Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA.

Ascomycota, the largest and most well-studied phylum of fungi, contains three subphyla: Saccharomycotina (budding yeasts), Pezizomycotina (filamentous fungi), and Taphrinomycotina (fission yeasts). Despite its importance, we lack a comprehensive genome-scale phylogeny or understanding of the similarities and differences in the mode of genome evolution within this phylum. By examining 1107 genomes from Saccharomycotina (332), Pezizomycotina (761), and Taphrinomycotina (14) species, we inferred a robust genome-wide phylogeny that resolves several contentious relationships and estimated that the Ascomycota last common ancestor likely originated in the Ediacaran period. Comparisons of genomic properties revealed that Saccharomycotina and Pezizomycotina differ greatly in their genome properties and enabled inference of the direction of evolutionary change. The Saccharomycotina typically have smaller genomes, lower guanine-cytosine contents, lower numbers of genes, and higher rates of molecular sequence evolution compared with Pezizomycotina. These results provide a robust evolutionary framework for understanding the diversity and ecological lifestyles of the largest fungal phylum.
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http://dx.doi.org/10.1126/sciadv.abd0079DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7673691PMC
November 2020

Convolutional neural networks improve fungal classification.

Sci Rep 2020 07 28;10(1):12628. Epub 2020 Jul 28.

Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584CT, Utrecht, The Netherlands.

Sequence classification plays an important role in metagenomics studies. We assess the deep neural network approach for fungal sequence classification as it has emerged as a successful paradigm for big data classification and clustering. Two deep learning-based classifiers, a convolutional neural network (CNN) and a deep belief network (DBN) were trained using our recently released barcode datasets. Experimental results show that CNN outperformed the traditional BLAST classification and the most accurate machine learning based Ribosomal Database Project (RDP) classifier on datasets that had many of the labels present in the training datasets. When classifying an independent dataset namely the "Top 50 Most Wanted Fungi", CNN and DBN assigned less sequences than BLAST. However, they could assign much more sequences than the RDP classifier. In terms of efficiency, it took the machine learning classifiers up to two seconds to classify a test dataset while it was 53 s for BLAST. The result of the current study will enable us to speed up the taxonomic assignments for the fungal barcode sequences generated at our institute as ~ 70% of them still need to be validated for public release. In addition, it will help to quickly provide a taxonomic profile for metagenomics samples.
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http://dx.doi.org/10.1038/s41598-020-69245-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7387343PMC
July 2020

sp. nov., isolated from flies feeding on a stinkhorn mushroom.

Int J Syst Evol Microbiol 2020 Sep 27;70(9):4908-4913. Epub 2020 Jul 27.

National Fungal Culture Collection of India (NFCCI), Biodiversity and Palaeobiology Group, MACS-Agharkar Research Institute, G.G. Agarkar Road, Pune, 411004, India.

The majority of species have been isolated from fungus-feeding insects and particularly from the gut of beetles. In the present study, seven yeast strains were isolated from the gut of species feeding on gleba, the spore-bearing inner mass, of a stinkhorn mushroom belonging to the family . Based on phenotypic, biochemical characterization and sequence analysis of the D1/D2 region of the large subunit rRNA gene and the internal transcribed spacer (ITS) region, two of these yeast strains, DGY3 and DGY4, represented a novel species of the genus . The novel species is closely related to an undescribed species of ST-370 (DQ404513) and with wherein, the novel species differs from by 40 nucleotide substitutions and three gaps (7.7 % sequence variation) in the D1/D2 region and 50 nucleotide substitutions and seven gaps (13.7 % sequence variation) in the ITS region. Several morphological and physiological differences were also observed between and the strains obtained during this study. These data support the proposal of as a novel species, with DGY3 as the holotype and CBS 16329 and MCC 1871 as ex-type strains.
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http://dx.doi.org/10.1099/ijsem.0.004358DOI Listing
September 2020

Hyphopichia lachancei, f.a., sp. nov., a yeast species from diverse origins.

Antonie Van Leeuwenhoek 2020 Jun 21;113(6):773-778. Epub 2020 Feb 21.

National Collection of Agricultural and Industrial Microorganisms, Faculty of Food Science, Szent István University, Somlói út 14-16, Budapest, 1118, Hungary.

Three strains originating from insect frass in South Africa, yellow foxglove in Hungary and soil in France, were characterised phenotypically and by sequencing of the D1/D2 domain of the large subunit and the ITS1-5.8S-ITS2 (ITS)-region of the rRNA gene. The strains have identical D1/D2 domain sequences and only one strain shows a 1 bp indel in a 9 bp homopolymer A/T repeat within the ITS-region. Based on sequence analysis Hyphopichia burtonii is the closest related species. The investigated strains differ from the type strain of H. burtonii by 1.9% (9 substitutions and an indel) in the D1/D2 domain and by 23 substitutions and 21-22 indels in the ITS-region. Since the sequence variability is very low among the three strains and the sequence divergence with the closely related H. burtonii exceeds the level generally encountered between species we propose the new species Hyphopichia lachancei f.a., sp. nov. to accommodate the three novel strains. From H. burtonii the new species can be distinguished phenotypically by its inability to ferment cellobiose and by the formation of endospores (Holotype: CBS 5999; Isotype: NCAIM Y.02228; MycoBank no.: MB833616).
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http://dx.doi.org/10.1007/s10482-020-01387-5DOI Listing
June 2020

sp. nov., a thermotolerant yeast isolated from distillery effluent.

Int J Syst Evol Microbiol 2019 Oct 25;69(10):3262-3267. Epub 2019 Jul 25.

Savitribai Phule Pune University, Ganeshkhind, Pune, 411007, India.

Ethanol production at high temperatures has garnered much interest in recent years and a key factor is the availability of thermotolerant yeasts. During an investigation on the diversity of thermotolerant yeasts from different habitats, a novel yeast species from the spent wash of a distillery unit associated with a sugar factory was isolated. Phylogenetic analysis of D1/D2 large subunit and ITS rRNA genes placed this species in the ascomycetous genus . The novel species can be distinguished from the closely related species using these rRNA gene regions. The cells of the new species are ovoid to ellipsoid with a diameter of 3.5-6.0×2.4-3.10 µm, while cells are cylindrical with a cell diameter of 1.5-3.0×6-23 µm. This novel species represents, together with , one of the two most thermotolerant yeast species in the genus , able to grow at 42 °C sp. nov. is proposed during this study.
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http://dx.doi.org/10.1099/ijsem.0.003616DOI Listing
October 2019

sp. nov., a d-xylose-fermenting yeast species isolated in Thailand.

Int J Syst Evol Microbiol 2019 Sep;69(9):2674-2680

Department of Microbiology, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand.

Three strains, representing a novel anamorphic and d-xylose-fermenting yeast species, were isolated from moss (ST-302), seawater (ST-1169) and peat (DMKU-XE12) collected from the southern part of Thailand. The three strains had identical sequences of the D1/D2 regions of the large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS) regions. CBS 10566 and CBS 11368 were the most closely related species with 7.9 % nucleotide substitutions in the D1/D2 regions of the LSU rRNA gene, and 10.3 and 12.6% nucleotide substitutions in the ITS regions, respectively. Phylogenetic analysis based on the concatenated sequences of the ITS and the D1/D2 regions confirmed that the three strains represented a distinct anamorphic species in the clade. Therefore, the three strains were described as a novel species, for which we propose the name sp. nov.
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http://dx.doi.org/10.1099/ijsem.0.003505DOI Listing
September 2019

First fungemia case due to environmental yeast Wickerhamomyces myanmarensis: detection by multiplex qPCR and antifungal susceptibility.

Future Microbiol 2019 03 12;14:267-274. Epub 2019 Mar 12.

Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands.

Aim: Presenting the first clinical case of Wickerhamomyces myanmarensis.

Patients & Methods: Yeast cells were isolated from blood and central venous catheter of a 5.5-year-old male subject. API 20C AUX, MALDI-TOF MS, ITS and LSU rDNA sequencing, and our qPCR assay were used for identification and the MIC values were determined by CLSI M27-A3.

Results: ITS and LSU rDNA sequencing identified both isolates as W. myanmarensis, while API 20C AUX and MALDI-TOF MS did not identify them correctly. Our qPCR specifically distinguished W. myanmarensis from W. anomalus. Isolate obtained from blood showed a higher MIC value for fluconazole, voriconazole and posaconazole.

Conclusion: Utilization of reliable identification tools might reveal the genuine spectrum of opportunistic yeast species.
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http://dx.doi.org/10.2217/fmb-2018-0253DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6482385PMC
March 2019

Eukaryotic Acquisition of a Bacterial Operon.

Cell 2019 03 21;176(6):1356-1366.e10. Epub 2019 Feb 21.

Laboratory of Genetics, Genome Center of Wisconsin, Wisconsin Energy Institute, J.F. Crow Institute for the Study of Evolution, University of Wisconsin-Madison, Madison, WI 53706, USA; DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53706, USA; Graduate Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706, USA. Electronic address:

Operons are a hallmark of bacterial genomes, where they allow concerted expression of functionally related genes as single polycistronic transcripts. They are rare in eukaryotes, where each gene usually drives expression of its own independent messenger RNAs. Here, we report the horizontal operon transfer of a siderophore biosynthesis pathway from relatives of Escherichia coli into a group of budding yeast taxa. We further show that the co-linearly arranged secondary metabolism genes are expressed, exhibit eukaryotic transcriptional features, and enable the sequestration and uptake of iron. After transfer, several genetic changes occurred during subsequent evolution, including the gain of new transcription start sites that were sometimes within protein-coding sequences, acquisition of polyadenylation sites, structural rearrangements, and integration of eukaryotic genes into the cluster. We conclude that the genes were likely acquired as a unit, modified for eukaryotic gene expression, and maintained by selection to adapt to the highly competitive, iron-limited environment.
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http://dx.doi.org/10.1016/j.cell.2019.01.034DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7295392PMC
March 2019

Tempo and Mode of Genome Evolution in the Budding Yeast Subphylum.

Cell 2018 11 8;175(6):1533-1545.e20. Epub 2018 Nov 8.

Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA. Electronic address:

Budding yeasts (subphylum Saccharomycotina) are found in every biome and are as genetically diverse as plants or animals. To understand budding yeast evolution, we analyzed the genomes of 332 yeast species, including 220 newly sequenced ones, which represent nearly one-third of all known budding yeast diversity. Here, we establish a robust genus-level phylogeny comprising 12 major clades, infer the timescale of diversification from the Devonian period to the present, quantify horizontal gene transfer (HGT), and reconstruct the evolution of 45 metabolic traits and the metabolic toolkit of the budding yeast common ancestor (BYCA). We infer that BYCA was metabolically complex and chronicle the tempo and mode of genomic and phenotypic evolution across the subphylum, which is characterized by very low HGT levels and widespread losses of traits and the genes that control them. More generally, our results argue that reductive evolution is a major mode of evolutionary diversification.
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http://dx.doi.org/10.1016/j.cell.2018.10.023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6291210PMC
November 2018

Diversity of yeast species from Dutch garden soil and the description of six novel Ascomycetes.

FEMS Yeast Res 2018 11;18(7)

Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands.

A Citizen Science initiative by the Westerdijk Fungal Biodiversity Institute and the Utrecht University Museum gave rise to a project where fungal and yeast isolates were obtained and identified from Dutch soil samples. During the current study, 386 yeast strains were isolated from 157 different locations in the Netherlands. These strains were identified using sequence data of the large-subunit rRNA gene (D1/D2 region) and the internal transcribed spacer 1 and 2 regions. A total of 53 different yeast species were found as well as 15 potentially novel species. Six novel ascomycetous species are described during this study that include Hanseniaspora mollemarum sp. nov., Ogataea degrootiae sp. nov., Pichia gijzeniarum sp. nov., Saccharomycopsis oosterbeekiorum sp. nov., Trichomonascus vanleenenius sp. nov. and Zygoascus flipseniorum sp. nov. This study made it possible to incorporate numerous yeast isolates into the CBS collection without any restrictions, which make these isolates readily available for use by others. Many of the isolates represented species of which only a few isolates or even only a single ex-type strain were available. Therefore, it is a clear indication that such biodiversity-orientated Citizen Science projects can enrich the pool of available yeasts for future research projects.
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http://dx.doi.org/10.1093/femsyr/foy076DOI Listing
November 2018

MALDI-TOF MS as a tool to identify foodborne yeasts and yeast-like fungi.

Int J Food Microbiol 2018 Feb 24;266:109-118. Epub 2017 Nov 24.

Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 Utrecht, The Netherlands. Electronic address:

Since food spoilage by yeasts causes high economic losses, fast and accurate identifications of yeasts associated with food and food-related products are important for the food industry. In this study the efficiency of the matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) to identify food related yeasts was evaluated. A CBS in-house MALDI-TOF MS database was created and later challenged with a blinded test set of 146 yeast strains obtained from food and food related products. Ninety eight percent of the strains were correctly identified with log score values>1.7. One strain, Mrakia frigida, gained a correct identification with a score value<1.7. Two strains could not be identified at first as they represented a mix of two different species. These mixes were Rhodotorula babjevae with Meyerozyma caribbica and Clavispora lusitaniae with Debaryomyces hansenii. After separation, all four species could be correctly identified with scores>1.7. Ambiguous identifications were observed due to two incorrect reference mass spectra's found in the commercial database BDAL v.4.0, namely Candida sake DSM 70763 which was re-identified as Candida oleophila, and Candida inconspicua DSM 70631 which was re-identified as Pichia membranifaciens. MALDI-TOF MS can distinguish between most of the species, but for some species complexes, such as the Kazachstania telluris and Mrakia frigida complexes, MALDI-TOF MS showed limited resolution and identification of sibling species was sometimes problematic. Despite this, we showed that the MALDI-TOF MS is applicable for routine identification and validation of foodborne yeasts, but a further update of the commercial reference databases is needed.
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http://dx.doi.org/10.1016/j.ijfoodmicro.2017.11.016DOI Listing
February 2018

Heitmania gen. nov., a new yeast genus in Microbotryomycetes, and description of three novel species: Heitmania litseae sp. nov., Heitmania castanopsis sp. nov. and Heitmania elacocarpi sp. nov.

Int J Syst Evol Microbiol 2017 Nov 21;67(11):4534-4540. Epub 2017 Sep 21.

State Key Laboratory for Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China.

Nine anamorphic yeast strains isolated from various plant leaves collected in southern China were phylogenetically characterized based on sequences of the internal transcribed spacer (ITS) region, the D1/D2 domains of the large subunit (LSU) rRNA gene, the small subunit (SSU) rRNA gene, the two subunits of the RNA polymerase II gene (RPB1 and RPB2) and the translation elongation factor 1-α (TEF1). Phylogenetic analysis of the combined sequences of the six genes showed that the new strains formed a distinct clade in the class Microbotryomycetes but could not be assigned to any of the existing genera, families or orders of the class. Three separate groups were consistently resolved from the nine new strains based on the combined sequences of the six genes and single gene sequences of ITS, RPB1, RPB2 and TEF1. The results suggest that the nine yeast strains compared represent three novel species in a novel genus. The names Heitmania gen. nov. (MycoBank registration number MB819987), Heitmania litseae sp. nov. (MB820112, type strain CGMCC 2.5697=CBS 14756), Heitmania castanopsis sp. nov. (MB819988, CGMCC 2.5698=CBS 14750) and Heitmania elacocarpi sp. nov. (MB820113, CGMCC 2.5695=CBS 14752) are proposed for the new taxa.
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http://dx.doi.org/10.1099/ijsem.0.002323DOI Listing
November 2017

Kondoa gutianensis f.a. sp. nov., a novel ballistoconidium-forming yeast species isolated from plant leaves.

Antonie Van Leeuwenhoek 2018 Jan 4;111(1):155-160. Epub 2017 Sep 4.

State Key Laboratory for Mycology, Institute of Microbiology, Chinese Academy of Sciences, 1-3 West Beichen Road, Chaoyang District, Beijing, 100101, China.

Two strains, GT-165 and GT-261, isolated from plant leaves collected from Gutian Mountain in Zhejiang province in China were identified as a novel species of the genus Kondoa by the sequence analysis of the internal transcribed spacer (ITS) region, the D1/D2 domains of the large subunit of rRNA (LSU rRNA) and the RNA polymerase II second largest subunit (RPB2), complemented by physiological tests. Phylogenetic analysis based on the concatenated sequences of ITS, D1/D2 and RPB2 showed that the closest known relatives of the new species are three undescribed Kondoa species and Kondoa thailandica. The ITS and D1/D2 sequences of the new species differ from the closely related species by 11-22% and 2-9%, respectively. The name Kondoa gutianensis f.a. sp. nov. (MB 820648, holotype = CGMCC 2.5703; isotype: CBS 14811 = CGMCC 2.5703) is proposed to accommodate the new taxon.
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http://dx.doi.org/10.1007/s10482-017-0936-1DOI Listing
January 2018

Nakazawaea todaengensis f.a., sp. nov., a yeast isolated from a peat swamp forest in Thailand.

Int J Syst Evol Microbiol 2017 Jul 21;67(7):2377-2382. Epub 2017 Jul 21.

Royal Society of Thailand, Bangkok, Thailand.

Strain DMKU-PS11(1)T was isolated from peat in a swamp forest in Thailand. DNA sequence analysis showed that it belonged to a novel species that was most closely related to Nakazawaea laoshanensis. However, it differed from the type strain of N. laoshanensis (NRRL Y-63634T) by 2.3 % nucleotide substitutions in the D1/D2 region of the large subunit (LSU) rRNA gene, 1.0 % nucleotide substitutions in the small subunit (SSU) rRNA gene and 8.0 % nucleotide substitutions in the internal transcribed spacer (ITS) region. The phylogenetic analyses based on the combined sequences of the SSU and the D1/D2 region and that of the SSU sequences alone confirmed the placement of the novel species in the Nakazawaea clade and its close affinity with N. laoshanensis. Hence, the species Nakazawaea todaengensis f.a., sp. nov. is proposed. The type strain is DMKU-PS11(1)T (=CBS 14555T=TBRC 6559T). The MycoBank number for Nakazawaea todaengensis f.a., sp. nov. is MB 819513.
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http://dx.doi.org/10.1099/ijsem.0.001961DOI Listing
July 2017

Optimization of cultivation conditions for biotechnological production of lipid by Rhodotorula kratochvilovae (syn, Rhodosporidium kratochvilovae) SY89 for biodiesel preparation.

3 Biotech 2017 Jun 8;7(2):145. Epub 2017 Jun 8.

Microbial, Cellular and Molecular Biology Department, College of Natural Science, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia.

Rhodotorula kratochvilovae (syn, Rhodosporidium kratochvilovae) SY89, an oleaginous yeast, isolated from Ethiopian soil, was grown under nitrogen-limited media. The capacity this with respect to biomass production, lipid yield and lipid content was evaluated. The influence of inoculum size, carbon sources, variations in glucose concentration, nitrogen sources, C/N ratio, pH, temperature, agitation, and aeration rate and incubation period were investigated. Inoculum size of 10% v/v, glucose as a carbon source at 50 g/L glucose, 0.50 g/L yeast extract and 0.31 g/L (NH)SO, C/N ratio of 120, pH 5.5, incubation temperature of 30 °C, 225 rpm, 0.2 as aeration ratio and 144 h of incubation were found to be optimum conditions for lipid production. Then the yeast was grown in a batch bioreactor by combining the different optimized parameters together. Under the optimized conditions, the yeast gave maximum biomass (15.34 ± 1.47 g/L), lipid yield (8.60 ± 0.81 g/L) and lipid content (56.06 ± 1.70%). The dominant fatty acids exhibited in order of their relative abundance (%w/w), were oleic, palmitic, linoleic, stearic, linolenic and palmitoleic acids. The concentration of saturated and monounsaturated fatty acids adds up 78.63 ± 2.19%. This suggests that this strain could be used as a good feedstock for biodiesel production.
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http://dx.doi.org/10.1007/s13205-017-0769-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5465050PMC
June 2017

Description of Hyphopichia buzzinii f.a., sp. nov. and Hyphopichia homilentoma comb. nov., the teleomorph of Candida homilentoma.

Antonie Van Leeuwenhoek 2017 Jul 6;110(7):985-994. Epub 2017 Apr 6.

Departamento de Microbiologia, ICB, C.P. 486, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil.

During studies of the yeast diversity associated with rotting wood in Brazil and fruits, plants and insects in French Guiana, three strains of a new species were isolated. Analysis of the sequences of the internal transcribed spacer (ITS)-5.8S and D1/D2 domains of the large subunit of the rRNA gene showed that this species belongs to the genus Hyphopichia and its closest relative is Candida homilentoma. These species differ by 44 nucleotide substitutions in D1/D2 sequences. A new species Hyphopichia buzzinii f. a., sp. nov., is proposed to accommodate these isolates. The type strain of Hyphopichia buzzinii sp. nov. is CLIB 1739 (=CBS 14300 = UFMG-CM-Y6121; MycoBank number is MB 815609). In addition, we isolated 11 strains of C. homilentoma from rotting wood, leaf surfaces, and water bodies in Brazil, and these strains when crossed among one another and with the type strain (CBS 6312) of this species, produced hat-shaped ascospores typical of the genus Hyphopichia. We describe the teleomorph of C. homilentoma as a new combination, Hyphopichia homilentoma comb. nov. (type strain CBS 6312; MycoBank number is MB 820009). We also propose to transfer the other six Candida species of the Hyphopichia clade to this genus as new combinations. Hyphopichia homilentoma produced ethanol and xylitol from D-xylose whereas H. buzzinii was only able to convert this pentose to xylitol.
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http://dx.doi.org/10.1007/s10482-017-0870-2DOI Listing
July 2017

Oleaginous yeasts from Ethiopia.

AMB Express 2016 Dec 15;6(1):78. Epub 2016 Sep 15.

CBS-KNAW Fungal Biodiversity Center, Uppsalalaan 8, P.O. Box: 85167, 3584 CT, Utrecht, The Netherlands.

Oleaginous microorganisms can produce high amounts of oil (>20 % of their biomass) under suitable cultivation conditions. In this research work 200 samples were collected from soil, plant surfaces (leaves, flowers and fruits), waste oils from traditional oil milling houses and dairy products (cheese, milk and yoghurt) in Ethiopia. Three hundred and forty yeast colonies were isolated from these samples. By applying Sudan III staining tests, 18 strains were selected as possible oleaginous yeasts. The 18 strains were identified and characterized for their lipid production as a feedstock for biodiesel production in the future. They were identified using morphological and physiological methods as well as sequencing the 3'end of the small-subunit rRNA gene, the internal transcribed spacer regions (ITS; ITS 1, ITS 2 and the intervening 5.8S rRNA gene), and the D1/D2 domain of the 26S rRNA gene. The 18 yeasts were identified as Cutaneotrichosporon curvatus (syn, Cryptococcus curvatus) (PY39), Rhodotorula kratochvilovae (syn, Rhodosporidium kratochvilovae) (SY89), Rhodotorula dairenensis (SY94) and Rhodotourula mucilaginosa (SY09, SY18, SY20, PY21, PY23, PY25, SY30, PY32, SY43, PY44, SY52, PY55, PY61, SY75 and PY86). Under nitrogen-limited cultivation conditions, R. mucilaginosa PY44 produced the highest biomass (15.10 ± 0.54 g/L), while R. mucilaginosa PY32 produced the lowest biomass (10.32 ± 0.18 g/L). The highest lipid yield of 6.87 ± 0.62 g/L and lipid content of 46.51 ± 0.70 % were attained by C. curvatus (syn, C. curvatus) PY39. On the other hand, R. mucilaginosa PY61 gave the lowest lipid yield (2.06 ± 0.52 g/L) and R. mucilaginosa SY52 gave the lowest lipid content of 16.99 ± 0.85 %. The results in this research work suggest that much more oleaginous yeasts can be isolated from Ethiopian environment. On the basis of their substantial lipid production abilities, the three oleaginous yeast strains PY39, SY89 and SY18 were selected and recommended for further optimization processes.
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http://dx.doi.org/10.1186/s13568-016-0242-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5025425PMC
December 2016

High-throughput screening of a large collection of non-conventional yeasts reveals their potential for aroma formation in food fermentation.

Food Microbiol 2016 Dec 25;60:147-59. Epub 2016 Jul 25.

NIZO Food Research B.V., P.O. Box 20, 6710 BA, Ede, The Netherlands.

Saccharomyces yeast species are currently the most important yeasts involved in industrial-scale food fermentations. However, there are hundreds of other yeast species poorly studied that are highly promising for flavour development, some of which have also been identified in traditional food fermentations. This work explores natural yeast biodiversity in terms of aroma formation, with a particular focus on aromas relevant for industrial fermentations such as wine and beer. Several non-Saccharomyces species produce important aroma compounds such as fusel alcohols derived from the Ehrlich pathway, acetate esters and ethyl esters in significantly higher quantities than the well-known Saccharomyces species. These species are Starmera caribaea, Hanseniaspora guilliermondii, Galactomyces geotrichum, Saccharomycopsis vini and Ambrosiozyma monospora. Certain species revealed a strain-dependent flavour profile while other species were very homogenous in their flavour profiles. Finally, characterization of a selected number of yeast species using valine or leucine as sole nitrogen sources indicates that the mechanisms of regulation of the expression of the Ehrlich pathway exist amongst non-conventional yeast species.
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http://dx.doi.org/10.1016/j.fm.2016.07.006DOI Listing
December 2016

Yeast culture collections in the twenty-first century: new opportunities and challenges.

Yeast 2016 07 17;33(7):243-60. Epub 2016 Jun 17.

Department of Agricultural, Food and Environmental Science, Industrial Yeasts Collection DBVPG, University of Perugia, Perugia, Italy.

The twenty-first century has brought new opportunities and challenges to yeast culture collections, whether they are long-standing or recently established. Basic functions such as archiving, characterizing and distributing yeasts continue, but with expanded responsibilities and emerging opportunities. In addition to a number of well-known, large public repositories, there are dozens of smaller public collections that differ in the range of species and strains preserved, field of emphasis and services offered. Several collections have converted their catalogues to comprehensive databases and synchronize them continuously through public services, making it easier for users worldwide to locate a suitable source for specific yeast strains and the data associated with these yeasts. In-house research such as yeast taxonomy continues to be important at culture collections. Because yeast culture collections preserve a broad diversity of species and strains within a species, they are able to make discoveries in many other areas as well, such as biotechnology, functional, comparative and evolution genomics, bioprocesses and novel products. Due to the implementation of the Convention of Biological Diversity (CBD) and the Nagoya Protocol (NP), there are new requirements for both depositors and users to ensure that yeasts were collected following proper procedures and to guarantee that the country of origin will be considered if benefits arise from a yeast's utilization. Intellectual property rights (IPRs) are extremely relevant to the current access and benefit-sharing (ABS) mechanisms; most research and development involving genetic resources and associated traditional knowledge will be subject to this topic. Copyright © 2016 John Wiley & Sons, Ltd.
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http://dx.doi.org/10.1002/yea.3171DOI Listing
July 2016

DNA barcoding revealed Nematodospora valgi gen. nov., sp. nov. and Candida cetoniae sp. nov. in the Lodderomyces clade.

Fungal Biol 2016 Feb 10;120(2):179-90. Epub 2015 Jun 10.

CBS Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands; State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; Shanghai Key Laboratory of Molecular Medical Mycology, Second Military Medical University, Changzheng Hospital, Institute of Dermatology and Medical Mycology, Shanghai 200003, China.

During a yeast biodiversity survey conducted in 2009-2011 in Bulgaria (South Eastern Europe) five strains of a novel ascomycetous yeast species were isolated from the beetle Valgus hemipterus (Cetoniinae) collected from two localities, namely Osogovska Planina Mountain and Nature Park Zlatni Pyasatsi. Phylogenetic analysis using combined sequences of the D1/D2 domains of the large subunit ribosomal DNA (LSU rDNA) and the internal transcribed spacers 1 + 2 regions (ITS1+2) placed the novel species on a separate branch near the basal part of the Lodderomyces clade. The novel species has a unique ascospore morphology distinct from those of the closely related teleomorphic genus Lodderomyces. Based on phylogenetic analysis and morphology of the ascospores we propose Nematodospora valgi gen. nov., sp. nov. to accommodate these isolates (MB811804 D37S(T), MB802458). Two strains of a novel anamorphic yeast species were isolated from the beetles Cetonia aurata and Oxythyrea funesta (Cetoniinae) collected in East Rhodopies and Sofia city, respectively. DNA barcoding analysis placed the new yeast species within the Candida parapsilosis subclade. Here, we present the description of a new yeast species, Candida cetoniae sp. nov. (IMB1R2(T), MB803501) to accommodate these two strains. The ecology and biogeography of the insect-associated yeasts of the Lodderomyces clade is discussed.
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http://dx.doi.org/10.1016/j.funbio.2015.05.008DOI Listing
February 2016

Reclassification of Saccharomycodes sinensis, Proposal of Yueomyces sinensis gen. nov., comb. nov. within Saccharomycetaceae (Saccharomycetales, Saccharomycotina).

PLoS One 2015 16;10(9):e0136987. Epub 2015 Sep 16.

CBS-KNAW Fungal Biodiversity Centre, Yeast Division, Utrecht, The Netherlands.

The phylogenetic position of Saccharomycodes sinensis has been debated by yeast taxonomists. In this study, a multigene phylogenetic analysis based on four regions, namely the 18S ribosomal DNA (rDNA), the D1/D2 domains of the 26S rDNA, the second largest subunit of RNA polymerase II gene (RPB2) and translation elongation factor 1-α gene (EF1-α), were performed to address the phylogenetic placement of S. sinensis. Our result indicated that S. sinensis belongs to Saccharomycetaceae instead of Saccharomycodaceae, and forms a single species lineage divergent from the other genera within Saccharomycetaceae. Yueomyces gen. nov. (MycoBank No. MB 811648) is proposed in the Saccharomycetaceae with Y. sinensis comb. nov. (MycoBank No. MB 811649, type strain CGMCC 2.01395T = IFO 10111T = CBS 7075T) as the type species.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0136987PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4573984PMC
June 2016

Phenotypic and molecular diversity of Meyerozyma guilliermondii strains isolated from food and other environmental niches, hints for an incipient speciation.

Food Microbiol 2015 Jun 20;48:206-15. Epub 2015 Jan 20.

Department of Pharmaceutical Sciences - Microbiology, University of Perugia, Borgo 20 Giugno 74, 06121 Perugia, Italy; CEMIN, Centre of Excellence on Nanostructured Innovative Materials, Department of Chemistry, Biology and Biotechnology, University of Perugia, via Elce di Sotto 8, I-06123 Perugia, Italy. Electronic address:

Meyerozyma guilliermondii is a yeast species widely isolated from several natural environments and from fruit; in medical microbiology it is known as the teleomorph of the opportunistic pathogen Candida guilliermondii, which causes about 2% of the human blood infections. This yeast is also promising in a variety of biotechnological applications as vitamins production and post-harvest control. The question if isolates from different sources are physiologically and genetically similar, or if the various environments induced significant differences, is crucial for the understanding of this species structure and to select strains appropriate for each application. This question was addressed using LSU and ITS sequencing for taxonomic assignment, i-SSR (GACA4) for the molecular characterization and FTIR for the metabolomic fingerprint. All data showed that fruit and environmental isolates cluster separately with a general good agreement between metabolomics and molecular analysis. An additional RAPD analysis was able to discriminate strains according to the isolation position within the pineapple fruit. Although all strains are members of the M. guilliermondii species according to the current standards, the distribution of large variability detected suggests that some specialization occurred in the niches inhabited by this yeast and that food related strains can be differentiated from the medical isolates.
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http://dx.doi.org/10.1016/j.fm.2014.12.014DOI Listing
June 2015

Analyses of black fungi by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS): species-level identification of clinical isolates of Exophiala dermatitidis.

FEMS Microbiol Lett 2015 Jan 4;362(1):1-6. Epub 2014 Dec 4.

Department of Infectious Diseases, Sahlgrenska Academy of the University of Gothenburg, SE-40234 Gothenburg, Sweden Culture Collection University of Gothenburg, Sahlgrenska Academy of the University of Gothenburg, SE-40234 Gothenburg, Sweden.

Conventional mycological identifications based on the recognition of morphological characteristics can be problematic. A relatively new methodology applicable for the identification of microorganisms is based on the exploitation of taxon- specific mass patterns recorded from abundant cell proteins directly from whole-cell preparations, using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). This study reports the application of MALDI-TOF MS for the differentiation and identifications of black yeasts, isolated from the respiratory tracts of patients with cystic fibrosis (CF). Initial phenotypic and DNA sequence-based analyses identified these isolates to be Exophiala dermatitidis. The type strains of E. dermatitidis (CBS 207.35(T)) and other species of Exophiala were included in the MALDI-TOF MS analyses to establish the references for comparing the mass spectra of the clinical isolates of Exophiala. MALDI-TOF MS analyses exhibited extremely close relationships among the clinical isolates and with the spectra generated from the type strain of E. dermatitidis. The relationships observed between the E. dermatitidis strains from the MALDI-TOF MS profiling analyses were supported by DNA sequence-based analyses of the rRNA ITS1 and ITS2 regions. These data demonstrated the applicability of MALDI-TOF MS as a reliable, rapid and cost-effective method for the identification of isolates of E. dermatitidis and other clinically relevant fungi and yeasts that typically are difficult to identify by conventional methods.
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http://dx.doi.org/10.1093/femsle/fnu016DOI Listing
January 2015

Finding needles in haystacks: linking scientific names, reference specimens and molecular data for Fungi.

Authors:
Conrad L Schoch Barbara Robbertse Vincent Robert Duong Vu Gianluigi Cardinali Laszlo Irinyi Wieland Meyer R Henrik Nilsson Karen Hughes Andrew N Miller Paul M Kirk Kessy Abarenkov M Catherine Aime Hiran A Ariyawansa Martin Bidartondo Teun Boekhout Bart Buyck Qing Cai Jie Chen Ana Crespo Pedro W Crous Ulrike Damm Z Wilhelm De Beer Bryn T M Dentinger Pradeep K Divakar Margarita Dueñas Nicolas Feau Katerina Fliegerova Miguel A García Zai-Wei Ge Gareth W Griffith Johannes Z Groenewald Marizeth Groenewald Martin Grube Marieka Gryzenhout Cécile Gueidan Liangdong Guo Sarah Hambleton Richard Hamelin Karen Hansen Valérie Hofstetter Seung-Beom Hong Jos Houbraken Kevin D Hyde Patrik Inderbitzin Peter R Johnston Samantha C Karunarathna Urmas Kõljalg Gábor M Kovács Ekaphan Kraichak Krisztina Krizsan Cletus P Kurtzman Karl-Henrik Larsson Steven Leavitt Peter M Letcher Kare Liimatainen Jian-Kui Liu D Jean Lodge Janet Jennifer Luangsa-ard H Thorsten Lumbsch Sajeewa S N Maharachchikumbura Dimuthu Manamgoda María P Martín Andrew M Minnis Jean-Marc Moncalvo Giuseppina Mulè Karen K Nakasone Tuula Niskanen Ibai Olariaga Tamás Papp Tamás Petkovits Raquel Pino-Bodas Martha J Powell Huzefa A Raja Dirk Redecker J M Sarmiento-Ramirez Keith A Seifert Bhushan Shrestha Soili Stenroos Benjamin Stielow Sung-Oui Suh Kazuaki Tanaka Leho Tedersoo M Teresa Telleria Dhanushka Udayanga Wendy A Untereiner Javier Diéguez Uribeondo Krishna V Subbarao Csaba Vágvölgyi Cobus Visagie Kerstin Voigt Donald M Walker Bevan S Weir Michael Weiß Nalin N Wijayawardene Michael J Wingfield J P Xu Zhu L Yang Ning Zhang Wen-Ying Zhuang Scott Federhen

Database (Oxford) 2014 30;2014. Epub 2014 Jun 30.

National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA, CBS-KNAW Fungal Biodiversity Centre, P.O. Box 85167, 3508 AD Utrecht, The Netherlands, Department of Pharmaceutical Sciences - Microbiology, Università degli Studi di Perugia, Perugia, Italy, Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Marie Bashir Institute for Infectious Diseases and Biosecurity, Sydney Medical School-Westmead Hospital, The University of Sydney, Westmead Millennium Institute, Westmead, Australia, Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, 405 30 Göteborg, Sweden, Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN 37920, USA, Illinois Natural History Survey, University of Illinois, 1816 South Oak Street, Champaign, IL 61820, USA, Mycology Section, Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3DS, UK, Natural History Museum, University of Tartu, 46 Vanemuise, 51014 Tartu, Estonia, Purdue University, Department of Botany and Plant Pathology, 915 W. State Street, West Lafayette, IN 47907, USA, Institute of Excellence in Fungal Research, and School of Science, Mae Fah Luang University, Chiang Rai 57100, Thailand, Imperial College London, Royal Botanic Gardens, Kew TW9 3DS, England, UK, Muséum National d'Histoire Naturelle, Dépt. Systématique et Evolution CP39, UMR7205, 12 Rue Buffon, F-75005 Paris, France, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, P. R. China, Departamento de Biología Vegetal II, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid 28040, Spain, Senckenberg Museum of Natural History Görlitz, PF 300 154, 02806 Görlitz, Germany, Department of Microbiology and Plant Pathology, Forestry Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0001, South Africa, Real Jardín Botánico, RJB-CSIC,

DNA phylogenetic comparisons have shown that morphology-based species recognition often underestimates fungal diversity. Therefore, the need for accurate DNA sequence data, tied to both correct taxonomic names and clearly annotated specimen data, has never been greater. Furthermore, the growing number of molecular ecology and microbiome projects using high-throughput sequencing require fast and effective methods for en masse species assignments. In this article, we focus on selecting and re-annotating a set of marker reference sequences that represent each currently accepted order of Fungi. The particular focus is on sequences from the internal transcribed spacer region in the nuclear ribosomal cistron, derived from type specimens and/or ex-type cultures. Re-annotated and verified sequences were deposited in a curated public database at the National Center for Biotechnology Information (NCBI), namely the RefSeq Targeted Loci (RTL) database, and will be visible during routine sequence similarity searches with NR_prefixed accession numbers. A set of standards and protocols is proposed to improve the data quality of new sequences, and we suggest how type and other reference sequences can be used to improve identification of Fungi. Database URL: http://www.ncbi.nlm.nih.gov/bioproject/PRJNA177353.
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http://dx.doi.org/10.1093/database/bau061DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4075928PMC
February 2015

Interlaboratory comparison of sample preparation methods, database expansions, and cutoff values for identification of yeasts by matrix-assisted laser desorption ionization-time of flight mass spectrometry using a yeast test panel.

J Clin Microbiol 2014 Aug 11;52(8):3023-9. Epub 2014 Jun 11.

CBS Fungal Biodiversity Centre (CBS-KNAW), Utrecht, the Netherlands Department of Dermatology, Shanghai Key Laboratory of Molecular Medical Mycology, Institute of Dermatology and Medical Mycology, Changzheng Hospital, Second Military Medical University, Shanghai, China State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China

An interlaboratory study using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) to determine the identification of clinically important yeasts (n = 35) was performed at 11 clinical centers, one company, and one reference center using the Bruker Daltonics MALDI Biotyper system. The optimal cutoff for the MALDI-TOF MS score was investigated using receiver operating characteristic (ROC) curve analyses. The percentages of correct identifications were compared for different sample preparation methods and different databases. Logistic regression analysis was performed to analyze the association between the number of spectra in the database and the percentage of strains that were correctly identified. A total of 5,460 MALDI-TOF MS results were obtained. Using all results, the area under the ROC curve was 0.95 (95% confidence interval [CI], 0.94 to 0.96). With a sensitivity of 0.84 and a specificity of 0.97, a cutoff value of 1.7 was considered optimal. The overall percentage of correct identifications (formic acid-ethanol extraction method, score ≥ 1.7) was 61.5% when the commercial Bruker Daltonics database (BDAL) was used, and it increased to 86.8% by using an extended BDAL supplemented with a Centraalbureau voor Schimmelcultures (CBS)-KNAW Fungal Biodiversity Centre in-house database (BDAL+CBS in-house). A greater number of main spectra (MSP) in the database was associated with a higher percentage of correct identifications (odds ratio [OR], 1.10; 95% CI, 1.05 to 1.15; P < 0.01). The results from the direct transfer method ranged from 0% to 82.9% correct identifications, with the results of the top four centers ranging from 71.4% to 82.9% correct identifications. This study supports the use of a cutoff value of 1.7 for the identification of yeasts using MALDI-TOF MS. The inclusion of enough isolates of the same species in the database can enhance the proportion of correctly identified strains. Further optimization of the preparation methods, especially of the direct transfer method, may contribute to improved diagnosis of yeast-related infections.
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http://dx.doi.org/10.1128/JCM.00563-14DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4136148PMC
August 2014

MycoBank gearing up for new horizons.

IMA Fungus 2013 Dec 17;4(2):371-9. Epub 2013 Dec 17.

CBS-KNAW Fungal Biodiversity Center, Uppsalalaan 8, 3584CT Utrecht, The Netherlands;

MycoBank, a registration system for fungi established in 2004 to capture all taxonomic novelties, acts as a coordination hub between repositories such as Index Fungorum and Fungal Names. Since January 2013, registration of fungal names is a mandatory requirement for valid publication under the International Code of Nomenclature for algae, fungi and plants (ICN). This review explains the database innovations that have been implemented over the past few years, and discusses new features such as advanced queries, registration of typification events (MBT numbers for lecto, epi- and neotypes), the multi-lingual database interface, the nomenclature discussion forum, annotation system, and web services with links to third parties. MycoBank has also introduced novel identification services, linking DNA sequence data to numerous related databases to enable intelligent search queries. Although MycoBank fills an important void for taxon registration, challenges for the future remain to improve links between taxonomic names and DNA data, and to also introduce a formal system for naming fungi known from DNA sequence data only. To further improve the quality of MycoBank data, remote access will now allow registered mycologists to act as MycoBank curators, using Citrix software.
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http://dx.doi.org/10.5598/imafungus.2013.04.02.16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3905949PMC
December 2013

Identification of medically relevant species of arthroconidial yeasts by use of matrix-assisted laser desorption ionization-time of flight mass spectrometry.

J Clin Microbiol 2013 Aug 15;51(8):2491-500. Epub 2013 May 15.

CBS-KNAW Fungal Biodiversity Centre, Utrecht, the Netherlands.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) was used for an extensive identification study of arthroconidial yeasts, using 85 reference strains from the CBS-KNAW yeast collection and 134 clinical isolates collected from medical centers in Qatar, Greece, and Romania. The test set included 72 strains of ascomycetous yeasts (Galactomyces, Geotrichum, Saprochaete, and Magnusiomyces spp.) and 147 strains of basidiomycetous yeasts (Trichosporon and Guehomyces spp.). With minimal preparation time, MALDI-TOF MS proved to be an excellent diagnostic tool that provided reliable identification of most (98%) of the tested strains to the species level, with good discriminatory power. The majority of strains were correctly identified at the species level with good scores (>2.0) and seven of the tested strains with log score values between 1.7 and 2.0. The MALDI-TOF MS results obtained were consistent with validated internal transcribed spacer (ITS) and/or large subunit (LSU) ribosomal DNA sequencing results. Expanding the mass spectrum database by increasing the number of reference strains for closely related species, including those of nonclinical origin, should enhance the usefulness of MALDI-TOF MS-based diagnostic analysis of these arthroconidial fungi in medical and other laboratories.
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http://dx.doi.org/10.1128/JCM.00470-13DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3719645PMC
August 2013

Yarrowia lipolytica: safety assessment of an oleaginous yeast with a great industrial potential.

Crit Rev Microbiol 2014 Aug 14;40(3):187-206. Epub 2013 Mar 14.

CBS-KNAW Fungal Biodiversity Centre, Institute of the Royal Netherlands Academy of Arts and Sciences , Utrecht , The Netherlands .

Yarrowia lipolytica has been developed as a production host for a large variety of biotechnological applications. Efficacy and safety studies have demonstrated the safe use of Yarrowia-derived products containing significant proportions of Yarrowia biomass (as for DuPont's eicosapentaenoic acid-rich oil) or with the yeast itself as the final product (as for British Petroleum's single-cell protein product). The natural occurrence of the species in food, particularly cheese, other dairy products and meat, is a further argument supporting its safety. The species causes rare opportunistic infections in severely immunocompromised or otherwise seriously ill people with other underlying diseases or conditions. The infections can be treated effectively by the use of regular antifungal drugs, and in some cases even disappeared spontaneously. Based on our assessment, we conclude that Y. lipolytica is a "safe-to-use" organism.
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http://dx.doi.org/10.3109/1040841X.2013.770386DOI Listing
August 2014