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Cene Gostinčar - One of the best experts on this subject based on the ideXlab platform.
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Virulence Traits and Population Genomics of the Black Yeast Aureobasidium melanogenum
'MDPI AG', 2021Co-Authors: Anja Černoša, Cene Gostinčar, Nina Gunde-cimerman, Xiaohuan Sun, Chao Fang, Zewei SongAbstract:The black yeast-like fungus Aureobasidium melanogenum is an opportunistic human pathogen frequently found indoors. Its traits, potentially linked to pathogenesis, have never been systematically studied. Here, we examine 49 A. melanogenum strains for growth at 37 °C, siderophore production, hemolytic activity, and assimilation of hydrocarbons and human neurotransmitters and report within-species variability. All but one strain grew at 37 °C. All strains produced siderophores and showed some hemolytic activity. The largest differences between strains were observed in the assimilation of hydrocarbons and human neurotransmitters. We show for the first time that fungi from the order Dothideales can assimilate aromatic hydrocarbons. To explain the background, we sequenced the genomes of all 49 strains and identified genes putatively involved in siderophore production and hemolysis. Genomic analysis revealed a fairly structured population of A.melanogenum, raising the possibility that some phylogenetic lineages have higher virulence potential than others. Population genomics indicated that the species is strictly clonal, although more than half of the genomes were diploid. The existence of relatively heterozygous diploids in an otherwise clonal species is described for only the second time in fungi. The genomic and phenotypic data from this study should help to resolve the non-trivial taxonomy of the genus Aureobasidium and reduce the medical hazards of exploiting the biotechnological potential of other, non-pathogenic species of this genus
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Fifty Aureobasidium pullulans genomes reveal a recombining polyextremotolerant generalist.
Environmental Microbiology, 2019Co-Authors: Cene Gostinčar, Martina Turk, Janja Zajc, Nina Gunde-cimermanAbstract:: The black yeast Aureobasidium pullulans is a textbook example of a generalistic and ubiquitous fungus thriving in a wide variety of environments. To investigate whether A. pullulans is a true generalist, or alternatively, whether part of its versatility can be attributed to intraspecific specialization masked by cryptic diversification undetectable by traditional phylogenetic analyses, we sequenced and analysed the genomes of 50 strains of A. pullulans from different habitats and geographic locations. No population structure was observed in the sequenced strains. Decay of linkage disequilibrium over shorter physical distances (
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Stress-Tolerant Yeasts: Opportunistic Pathogenicity Versus Biocontrol Potential
MDPI AG, 2019Co-Authors: Janja Zajc, Cene Gostinčar, Anja Černoša, Nina Gunde-cimermanAbstract:Stress-tolerant fungi that can thrive under various environmental extremes are highly desirable for their application to biological control, as an alternative to chemicals for pest management. However, in fungi, the mechanisms of stress tolerance might also have roles in mammal opportunism. We tested five species with high biocontrol potential in agriculture (Aureobasidium pullulans, Debayomyces hansenii, Meyerozyma guilliermondii, Metschnikowia fructicola, Rhodotorula mucilaginosa) and two species recognized as emerging opportunistic human pathogens (Exophiala dermatitidis, Aureobasidium melanogenum) for growth under oligotrophic conditions and at 37 °C, and for tolerance to oxidative stress, formation of biofilms, production of hydrolytic enzymes and siderophores, and use of hydrocarbons as sole carbon source. The results show large overlap between traits desirable for biocontrol and traits linked to opportunism (growth under oligotrophic conditions, production of siderophores, high oxidative stress tolerance, and specific enzyme activities). Based on existing knowledge and these data, we suggest that oligotrophism and thermotolerance together with siderophore production at 37 °C, urease activity, melanization, and biofilm production are the main traits that increase the potential for fungi to cause opportunistic infections in mammals. These traits should be carefully considered when assessing safety of potential biocontrol agents
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genome sequencing of four Aureobasidium pullulans varieties biotechnological potential stress tolerance and description of new species
BMC Genomics, 2014Co-Authors: Cene Gostinčar, Martina Turk, Janja Zajc, Tina Kogej, Silva Sonjak, Polona Zalar, Martin Grube, Aditi Sharma, Jennifer Chiniquy, Chew Yee NganAbstract:Aureobasidium pullulans is a black-yeast-like fungus used for production of the polysaccharide pullulan and the antimycotic aureobasidin A, and as a biocontrol agent in agriculture. It can cause opportunistic human infections, and it inhabits various extreme environments. To promote the understanding of these traits, we performed de-novo genome sequencing of the four varieties of A. pullulans. The 25.43-29.62 Mb genomes of these four varieties of A. pullulans encode between 10266 and 11866 predicted proteins. Their genomes encode most of the enzyme families involved in degradation of plant material and many sugar transporters, and they have genes possibly associated with degradation of plastic and aromatic compounds. Proteins believed to be involved in the synthesis of pullulan and siderophores, but not of aureobasidin A, are predicted. Putative stress-tolerance genes include several aquaporins and aquaglyceroporins, large numbers of alkali-metal cation transporters, genes for the synthesis of compatible solutes and melanin, all of the components of the high-osmolarity glycerol pathway, and bacteriorhodopsin-like proteins. All of these genomes contain a homothallic mating-type locus. The differences between these four varieties of A. pullulans are large enough to justify their redefinition as separate species: A. pullulans, A. melanogenum, A. subglaciale and A. namibiae. The redundancy observed in several gene families can be linked to the nutritional versatility of these species and their particular stress tolerance. The availability of the genome sequences of the four Aureobasidium species should improve their biotechnological exploitation and promote our understanding of their stress-tolerance mechanisms, diverse lifestyles, and pathogenic potential.
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redefinition of Aureobasidium pullulans and its varieties
Studies in Mycology, 2008Co-Authors: Polona Zalar, Cene Gostinčar, G S De Hoog, Viktor Ursic, M Sudhadham, Nina GundecimermanAbstract:Using media with low water activity, a large numbers of Aureobasidium-like black yeasts were isolated from glacial and subglacial ice of three polythermal glaciers from the coastal Arctic environment of Kongsfjorden (Svalbard, Spitsbergen), as well as from adjacent sea water, sea ice and glacial meltwaters. To characterise the genetic variability of Aureobasidium pullulans strains originating from the Arctic and strains originating pan-globally, a multilocus molecular analysis was performed, through rDNA (internal transcribed spacers, partial 28 S rDNA), and partial introns and exons of genes encoding beta-tubulin (TUB), translation elongation factor (EF1alpha) and elongase (ELO). Two globally ubiquitous varieties were distinguished: var. pullulans, occurring particularly in slightly osmotic substrates and in the phyllosphere; and var. melanogenum, mainly isolated from watery habitats. Both varieties were commonly isolated from the sampled Arctic habitats. However, some Aureobasidium-like strains from subglacial ice from three different glaciers in Kongsfjorden (Svalbard, Spitsbergen), appeared to represent a new variety of A. pullulans. A strain from dolomitic marble in Namibia was found to belong to yet another variety. No molecular support has as yet been found for the previously described var. aubasidani. A partial elongase-encoding gene was successfully used as a phylogenetic marker at the (infra-)specific level.
Zhe Chi - One of the best experts on this subject based on the ideXlab platform.
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genome editing of different strains of Aureobasidium melanogenum using an efficient cre loxp site specific recombination system
Fungal Biology, 2019Co-Authors: Zhao Zhang, Guanglei Liu, Zhe Chi, Hong Jiang, Zhenming ChiAbstract:Abstract It has been well known that different strains of Aureobasidium spp. can produce commercial pullulan, polymalate, liamocin, intracellular lipids, gluconic acid, siderophore, melanin and various enzymes. In order to fully elucidate their synthetic pathways and regulation, it is necessary to have an efficient gene editing system for genetic modification of Aureobasidium spp. In this study, an efficient Cre/loxp site-specific recombination system (pAMGDloxp-1, pAMEXlox-1 and pAMCRE1) was constructed. It was found that they could be successfully used to sequentially delete and express many genes in different strains of A. melanogenum. After each round of gene disruption and expression, over 0.5 positive cells per 1000 competent cells and over 49.8 positive transformants per 1.0 μg DNA were achieved. After each round of the antibiotics gene excision by using the Cre-loxp site-specific recombination, over 95.4 % of the antibiotics-resistant cells became sensitive to both hygromycin B and nourseothricin again. This demonstrated that the Cre/loxp site-specific recombination system constructed in this study can efficiently be used to simultaneously delete and express many genes in different strains of A. melanogenum. These systems are promising approaches for the easily modifying genomics of the yeast-like fungal strains with enhanced metabolic pathways through multicopy gene deletion and expression.
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overexpression of a pyruvate carboxylase gene enhances extracellular liamocin and intracellular lipid biosynthesis by Aureobasidium melanogenum m39
Process Biochemistry, 2018Co-Authors: Ruirui Tang, Guanglei Liu, Zhe Chi, Hong Jiang, Sijia Xue, Zhenming ChiAbstract:Abstract The pyruvate carboxylase-encoding PYC1 gene from the yeast strain Aureobasidium sp. P6, which is a polymalate over-producer, was actively overexpressed in the marine-derived yeast Aureobasidium melanogenum 9-1, which is a heavy oil (liamocin) producer. The resulting PYC1-over-expressing transformant M39 produced 35.3 ± 1.2 g/l liamocins and 24.6 ± 0.5% (w/w) intracellular oil, and its cell dry weight was 17.0 ± 1.6 g/l. On the other hand, wild-type strain 9-1 only produced 27.4 ± 0.3 g/l liamocins and 22.6 ± 0.8% (w/w) intracellular oil and had a cell dry weight of 15.3 ± 2.0 g/l within 168 h. The results suggested that the over-expression of the PYC1 gene enhanced the biosynthesis of liamocins and intracellular lipids in transformant M39 due to the enhanced biosynthesis of citric acid, which could be the precursor for the biosynthesis of the intracellular lipids and extracellular liamocins. During fermentation, 43.04 ± 1.2 g/l of extracellular liamocins, 17.7 ± 0.5 g/l of cell dry weight and 23.8 ± 0.2 g/l of intracellular lipids were produced by transformant M39 within 156 h, leaving 2.1% reducing sugar in the fermented medium. Moreover, the strong alkaline hydrolysis products of the extracellular liamocins mainly contained 5-hydroxy-2-decenoic acid lactone (92.1 ± 0.3%), hexadecanoic acids (C16:0, 3.3 ± 0.04%), octadecadienoic acids (C18:2, 1.0 ± 0.2%) and octadecanoic acids (C18:0, 3.6 ± 0.01%), while the intracellular lipids mainly contained C16:0, C16:1, C18:0, C18:1 and C18:2 fatty acids.
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poly β l malic acid pmla from Aureobasidium spp and its current proceedings
Applied Microbiology and Biotechnology, 2016Co-Authors: Zhe Chi, Guanglei Liu, Chenguang Liu, Zhenming ChiAbstract:Poly(β-l-malic acid) is one natural biopolymer that has the outstanding features of biocompatibility, biodegradability, water solubility, and non-immunogenicity, and it is easily chemically modified. So poly(β-l-malic acid) (PMLA) and its derivatives may have a great potential application as a novel drug delivery system and in the production of advanced biomaterials which have attracted so much research attention. The fungi of Aureobasidium spp. have been discovered to be the most suitable candidates for PMLA production in large quantities which satisfy the demand of either research or industry. In this review, we will give an overall summary about the PMLA produced by Aureobasidium spp. based on related research in the last decades and the elaboration of this PMLA producer will also be accomplished. More importantly, the latest proceedings will be specified and some suggestions to the elucidation of a PMLA biosynthesis pathway which remains undefined up to date will be proposed. Finally, through this review, the further exploitation for the application of PMLA from Aureobasidium spp. can be emphasized and promoted.
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optimization of medium and cultivation conditions for alkaline protease production by the marine yeast Aureobasidium pullulans
Bioresource Technology, 2007Co-Authors: Zhe Chi, Peng WangAbstract:A yeast strain, Aureobasidium pullulans, which could produce the high yield of protease was isolated from sediment of saltern in Qingdao, China. Maximum production of enzyme (623.1 U/mg protein; 7.2 U/ml) was obtained in a medium containing 2.5 g soluble starch and 2.0 g NaNO(3), 100ml seawater, initial pH 6.0, after fermentation at 24.5 degrees C for 30 h. The protease had the highest activity at pH 9.0 and 45 degrees C.
Deanna A. Sutton - One of the best experts on this subject based on the ideXlab platform.
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in vitro activities of eight antifungal drugs against 104 environmental and clinical isolates of Aureobasidium pullulans
Antimicrobial Agents and Chemotherapy, 2014Co-Authors: Javad M Najafzadeh, Saradeghi M Keisari, Hossein Zarrinfar, Anuradha Chowdhary, Sybren G De Hoog, Deanna A. Sutton, Jacques F.g.m. MeisAbstract:Aureobasidium pullulans is an unusual agent of phaeohyphomycosis. The in vitro activities of antifungals against 104 isolates of Aureobasidium pullulans var. pullulans and A. pullulans var. melanigenum revealed low MIC90s of amphotericin B, posaconazole, and itraconazole. However, they were resistant to fluconazole (≥64 μg/ml) and had high MICs of voriconazole, isavuconazole, caspofungin, and micafungin.
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Aureobasidium pullulans var melanigenum fungemia in a pediatric patient
Medical Mycology, 2011Co-Authors: Kileen L Mershonshier, Jaime G Deville, Shirley Delair, Sybren G De Hoog, Annette W. Fothergill, Brian L. Wickes, Deanna A. Sutton, Michael A LewinskiAbstract:This report describes a chronically ill child who presented with high fever and was diagnosed with catheter-related sepsis. Aureobasidium pullulans variety melanigenum, a dematiaceous fungus that rarely causes opportunistic infections, was recovered from multiple blood cultures. Antifungal susceptibilities were performed and the minimum inhibitory concentration (MIC) for fluconazole was 64 mg/l, suggestive of fluconazole resistance. The patient made a full recovery after removal of the catheter line and treatment with liposomal amphotericin B. This is the first case report of an elevated in vitro fluconazole MIC of an A. pullulans isolate and only the third case of successful treatment of A. pullulans fungemia.
Sybren G De Hoog - One of the best experts on this subject based on the ideXlab platform.
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in vitro activities of eight antifungal drugs against 104 environmental and clinical isolates of Aureobasidium pullulans
Antimicrobial Agents and Chemotherapy, 2014Co-Authors: Javad M Najafzadeh, Saradeghi M Keisari, Hossein Zarrinfar, Anuradha Chowdhary, Sybren G De Hoog, Deanna A. Sutton, Jacques F.g.m. MeisAbstract:Aureobasidium pullulans is an unusual agent of phaeohyphomycosis. The in vitro activities of antifungals against 104 isolates of Aureobasidium pullulans var. pullulans and A. pullulans var. melanigenum revealed low MIC90s of amphotericin B, posaconazole, and itraconazole. However, they were resistant to fluconazole (≥64 μg/ml) and had high MICs of voriconazole, isavuconazole, caspofungin, and micafungin.
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Aureobasidium pullulans var melanigenum fungemia in a pediatric patient
Medical Mycology, 2011Co-Authors: Kileen L Mershonshier, Jaime G Deville, Shirley Delair, Sybren G De Hoog, Annette W. Fothergill, Brian L. Wickes, Deanna A. Sutton, Michael A LewinskiAbstract:This report describes a chronically ill child who presented with high fever and was diagnosed with catheter-related sepsis. Aureobasidium pullulans variety melanigenum, a dematiaceous fungus that rarely causes opportunistic infections, was recovered from multiple blood cultures. Antifungal susceptibilities were performed and the minimum inhibitory concentration (MIC) for fluconazole was 64 mg/l, suggestive of fluconazole resistance. The patient made a full recovery after removal of the catheter line and treatment with liposomal amphotericin B. This is the first case report of an elevated in vitro fluconazole MIC of an A. pullulans isolate and only the third case of successful treatment of A. pullulans fungemia.
Jacques F.g.m. Meis - One of the best experts on this subject based on the ideXlab platform.
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in vitro activities of eight antifungal drugs against 104 environmental and clinical isolates of Aureobasidium pullulans
Antimicrobial Agents and Chemotherapy, 2014Co-Authors: Javad M Najafzadeh, Saradeghi M Keisari, Hossein Zarrinfar, Anuradha Chowdhary, Sybren G De Hoog, Deanna A. Sutton, Jacques F.g.m. MeisAbstract:Aureobasidium pullulans is an unusual agent of phaeohyphomycosis. The in vitro activities of antifungals against 104 isolates of Aureobasidium pullulans var. pullulans and A. pullulans var. melanigenum revealed low MIC90s of amphotericin B, posaconazole, and itraconazole. However, they were resistant to fluconazole (≥64 μg/ml) and had high MICs of voriconazole, isavuconazole, caspofungin, and micafungin.
