Diego Libkind
Research interests
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InterestsYeast, Yeast Genetics, Fermentation Biotechnology
Publications
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9.43Impact points
Microbe domestication and the identification of the wild genetic stock of lager-brewing yeast.
Proceedings of the National Academy of Sciences of the United States of America. 08/2011; 108(35):14539-44.
Domestication of plants and animals promoted humanity's transition from nomadic to sedentary lifestyles, demographic expansion, and the emergence of civilizations. In contrast to the well-documented successes of crop and livestock breeding, processes of microbe domestication remain obscure, desp... [more] Domestication of plants and animals promoted humanity's transition from nomadic to sedentary lifestyles, demographic expansion, and the emergence of civilizations. In contrast to the well-documented successes of crop and livestock breeding, processes of microbe domestication remain obscure, despite the importance of microbes to the production of food, beverages, and biofuels. Lager-beer, first brewed in the 15th century, employs an allotetraploid hybrid yeast, Saccharomyces pastorianus (syn. Saccharomyces carlsbergensis), a domesticated species created by the fusion of a Saccharomyces cerevisiae ale-yeast with an unknown cryotolerant Saccharomyces species. We report the isolation of that species and designate it Saccharomyces eubayanus sp. nov. because of its resemblance to Saccharomyces bayanus (a complex hybrid of S. eubayanus, Saccharomyces uvarum, and S. cerevisiae found only in the brewing environment). Individuals from populations of S. eubayanus and its sister species, S. uvarum, exist in apparent sympatry in Nothofagus (Southern beech) forests in Patagonia, but are isolated genetically through intrinsic postzygotic barriers, and ecologically through host-preference. The draft genome sequence of S. eubayanus is 99.5% identical to the non-S. cerevisiae portion of the S. pastorianus genome sequence and suggests specific changes in sugar and sulfite metabolism that were crucial for domestication in the lager-brewing environment. This study shows that combining microbial ecology with comparative genomics facilitates the discovery and preservation of wild genetic stocks of domesticated microbes to trace their history, identify genetic changes, and suggest paths to further industrial improvement.
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3.60Impact points
Yeast communities associated with the bulk-soil, rhizosphere and ectomycorrhizosphere of a Nothofagus pumilio forest in northwestern Patagonia, Argentina.
FEMS microbiology ecology. 08/2011; 78(3):531-41.
Soil microorganisms play an important role in soil quality and they interact closely with vegetation. Little is known about yeast diversity and function in forest soil ecosystems and their interactions with other biotic soil components, particularly in the mycorrhizosphere. We studied the diversity ... [more] Soil microorganisms play an important role in soil quality and they interact closely with vegetation. Little is known about yeast diversity and function in forest soil ecosystems and their interactions with other biotic soil components, particularly in the mycorrhizosphere. We studied the diversity of yeasts inhabiting the bulk-soil, rhizosphere and ectomycorrhizosphere of a Nothofagus pumilio forest in Nahuel Huapi National Park (Bariloche, Argentina). Ectomycorrhizal infection was observed in all N. pumilio trees studied. A total of 126 yeast isolates were obtained, including 18 known and three possibly new species. Basidiomycetous yeasts were predominant in all soil fractions, and the most frequently isolated species was Cryptococcus podzolicus. Diversity indices and multivariate analyses were used to study and compare yeast communities in the bulk-soil, rhizosphere and ectomycorrhizosphere. Yeasts able to ferment glucose were found associated with the rhizosphere. Many of the recovered yeast species were associated with lignocelluloses compound degradation, which suggest that yeast plays an important role as a decomposer in these forest soils. Each soil fraction has a distinct yeast assemblage related to their physiologic capacities and soil nutrient availability.
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1.81Impact points
Phylogenetic distribution of fungal mycosporines within the Pucciniomycotina (Basidiomycota).
Yeast (Chichester, England). 08/2011; 28(8):619-27.
The synthesis of the UV Absorbing compounds named mycosporines (MYCs) has been detected in a few basidiomycetous yeast groups. Conspicuous accumulation of mycosporine-glutaminol-glucoside (MGG) in yeasts requires photo-induction and its photoprotective function has been postulated. The distribution ... [more] The synthesis of the UV Absorbing compounds named mycosporines (MYCs) has been detected in a few basidiomycetous yeast groups. Conspicuous accumulation of mycosporine-glutaminol-glucoside (MGG) in yeasts requires photo-induction and its photoprotective function has been postulated. The distribution of the ability to produce MYCs appeared to be related to the yeast taxonomic affiliation. In view of the potential significance of MYCs in yeast taxonomy, we here studied the distribution of this trait among dimorphic basidiomycetes of the Pucciniomycotina. Of the 94 fungal species (377 strains and 33 genera) tested, almost half were MYC-positive and MGG was the main compound produced. MGG synthesis was observed for representatives of five of seven Pucciniomycotina classes, indicating that this trait is widely distributed in this group. MGG detection proved useful for the differentiation of species of the polyphyletic genera, such as Rhodotorula and Sporobolomyces, that are phylogenetically separated. MGG quantification and UV tolerance studies in Cystobasidiomycetes supported the idea that the habitat of origin of each strains is important in the level of MGG synthesis and that MYCs have a photoprotective function in yeasts. The taxonomic value of this trait in fungal systematics is discussed.
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Microbe domestication and the identification of the wild genetic stock of lager-brewing yeast 10.1073/pnas.1105430108
01/2011; 108:14539-14544.
Domestication of plants and animals promoted humanity's transition from nomadic to sedentary lifestyles, demographic expansion, and the emergence of civilizations. In contrast to the well-documented successes of crop and livestock breeding, processes of microbe domestication remain obscure, desp... [more] Domestication of plants and animals promoted humanity's transition from nomadic to sedentary lifestyles, demographic expansion, and the emergence of civilizations. In contrast to the well-documented successes of crop and livestock breeding, processes of microbe domestication remain obscure, despite the importance of microbes to the production of food, beverages, and biofuels. Lager-beer, first brewed in the 15th century, employs an allotetraploid hybrid yeast, Saccharomyces pastorianus (syn. Saccharomyces carlsbergensis), a domesticated species created by the fusion of a Saccharomyces cerevisiae ale-yeast with an unknown cryotolerant Saccharomyces species. We report the isolation of that species and designate it Saccharomyces eubayanus sp. nov. because of its resemblance to Saccharomyces bayanus (a complex hybrid of S. eubayanus, Saccharomyces uvarum, and S. cerevisiae found only in the brewing environment). Individuals from populations of S. eubayanus and its sister species, S. uvarum, exist in apparent sympatry in Nothofagus (Southern beech) forests in Patagonia, but are isolated genetically through intrinsic postzygotic barriers, and ecologically through host-preference. The draft genome sequence of S. eubayanus is 99.5% identical to the non-S. cerevisiae portion of the S. pastorianus genome sequence and suggests specific changes in sugar and sulfite metabolism that were crucial for domestication in the lager-brewing environment. This study shows that combining microbial ecology with comparative genomics facilitates the discovery and preservation of wild genetic stocks of domesticated microbes to trace their history, identify genetic changes, and suggest paths to further industrial improvement.
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2.95Impact points
UVB photoprotective role of mycosporines in yeast: photostability and antioxidant activity of mycosporine-glutaminol-glucoside.
Radiation research. 01/2011; 175(1):44-50.
Several yeast species are able to synthesize and accumulate UV-radiation-absorbing mycosporine metabolites that are of unclear physiological function. In this work we analyzed the relationship between mycosporine-glutaminol glucoside (MGG) production, cell survival after UVB irradiation, and formati... [more] Several yeast species are able to synthesize and accumulate UV-radiation-absorbing mycosporine metabolites that are of unclear physiological function. In this work we analyzed the relationship between mycosporine-glutaminol glucoside (MGG) production, cell survival after UVB irradiation, and formation of cyclobutane pyrimidine dimers (CPDs). We also assessed the photostability and singlet oxygen quenching activity of MGG. A set of nine isolates of the basidiomycetous yeast Cryptococcus steppossus cultured in both dark and light conditions was used for the studies. Survival of the UVB-irradiated isolates and MGG concentration had a linear relationship when the concentration was over 2.5 mg g(-1). CPD accumulation and MGG accumulation were inversely related. MGG in aqueous solution was photostable with a photodecomposition quantum yield of 1.16 × 10(-5). MGG quenching of singlet oxygen was also observed, and the rate constant for the process in D(2)O was 5.9 × 10(7) M(-1) s(-1). Our results support the idea that MGG plays an important role as a UVB photoprotective metabolite in yeasts by protecting against direct damage on DNA and probably against indirect damage by singlet oxygen quenching.
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3.60Impact points
Yeasts from an oligotrophic lake in Patagonia (Argentina): diversity, distribution and synthesis of photoprotective compounds and extracellular enzymes.
FEMS microbiology ecology. 01/2011; 76(1):1-13.
Nahuel Huapi (NH) Lake is an oligotrophic temperate lake of glacial origin with high transparency, surrounded by well-developed forests and located at San Carlos de Bariloche, Nahuel Huapi National Park, in Patagonia, Argentina. In this lake, we characterized yeast distribution and diversity along a... [more] Nahuel Huapi (NH) Lake is an oligotrophic temperate lake of glacial origin with high transparency, surrounded by well-developed forests and located at San Carlos de Bariloche, Nahuel Huapi National Park, in Patagonia, Argentina. In this lake, we characterized yeast distribution and diversity along a south-to-north transect and established a relationship between the ability to produce photoprotective compounds (PPCs) (carotenoid pigments and mycosporines) and the occurrence of yeast at different collection points. Subsurface water samples were filtered for yeast isolation. Total yeast counts ranged between 22 and 141 CFU L(-1) , and the highest values corresponded to the most impacted sites. Littoral sites had a low proportion of yeast-producing PPCs and this group prevailed in pelagic sites. This is probably a result of the high transparency of the water and the increased UV exposure. The yeast community from NH Lake showed a high species richness and a uniform distribution of taxa between pelagic and border collection points. Yeasts were identified as belonging to 14 genera and 34 species. Rhodotorula mucilaginosa and Cryptococcus victoriae were the most frequently found species, representing 14.4% and 13.6% of the total yeast isolates, respectively. Most of the yeast isolates demonstrated at least one extracellular enzymatic activity (mainly cellulase and lipase activities), which suggested that these microorganisms are metabolically active in the lake.
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1.79Impact points
Production of the UVB-absorbing compound mycosporine-glutaminol-glucoside by Xanthophyllomyces dendrorhous (Phaffia rhodozyma).
FEMS yeast research. 09/2010; 11(1):52-9.
The ability of the basidiomycetous yeast Xanthophyllomyces dendrorhous (Phaffia rhodozyma) to accumulate astaxanthin is responsible for the industrial use of this yeast as a microbial source of pigments for aquaculture. It is also hypothesized that astaxanthin accounts for its ability to thrive in h... [more] The ability of the basidiomycetous yeast Xanthophyllomyces dendrorhous (Phaffia rhodozyma) to accumulate astaxanthin is responsible for the industrial use of this yeast as a microbial source of pigments for aquaculture. It is also hypothesized that astaxanthin accounts for its ability to thrive in highly oxidative and UV-exposed habitats. Here, we assessed the ability of this species to synthesize UV-absorbing compounds generally known as mycosporines, evaluated the effect of culture media in the production of these compounds and compared its UV growth resistance and tolerance with other yeasts. The 48 wild and collection strains screened were positive for mycosporines and a unique compound identified as mycosporine-glutaminol-glucoside (MGG) was detected. Thus, the ability of X. dendrorhous to produce MGG, as described here for the first time, is so far unique among the Cystofilobasidiales. The compound was synthesized constitutively, although growth under visible light and, to a greater extent, UVA radiation stimulated its production. Strains from UV-exposed habitats produced larger quantities and oligotrophic complex media seemed to favor MGG accumulation. UV tolerance and survival of X. dendrorhous was high and comparable to that of the polyextremophilic Rhodotorula mucilaginosa. The taxonomical and ecological implications of the production of MGG by X. dendrorhous are discussed.
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2.71Impact points
Photoprotection by carotenoid pigments in the yeast Rhodotorula mucilaginosa: the role of torularhodin.
Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology. 08/2010; 9(8):1145-51.
In this paper we report the relationship between carotenoids and ergosterol and cell UV-B resistance in different strains of the yeast Rhodotorula mucilaginosa. Cell survival was studied using a set of 13 strains; additionally, two mutants (a hyper-producing one and a colourless one) in combination ... [more] In this paper we report the relationship between carotenoids and ergosterol and cell UV-B resistance in different strains of the yeast Rhodotorula mucilaginosa. Cell survival was studied using a set of 13 strains; additionally, two mutants (a hyper-producing one and a colourless one) in combination with diphenylamine (DPA), a carotenogenesis inhibitor, were used. A positive correlation between total carotenoids and survival to UV-B radiation was found. However, when individual carotenoid concentrations were tested, only torularhodin was found to be significantly related to UV-B survival. On the contrary, ergosterol did not affect survival. The hyper-pigmented strain showed an enhanced survival (up to 250%) compared to the parental strain, while the survival of the albino mutant was similar to that experienced by the parental strain; however, observed changes in survival were dose dependent. The cyclobutane pyrimidine dimers (CPDs), one of the major forms of DNA damage caused by UV exposure, appears as unrelated to the accumulation of carotenoids and cell survival. These results indicate that bearing higher torularhodin concentrations enhances UV-B survival in yeasts and, thus, the accumulation of this pigment constitutes an important mechanism that improves the resistance of yeasts to UV-B.
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2.11Impact points
Description of Holtermanniella gen. nov., including Holtermanniella takashimae sp. nov. and four new combinations, and proposal of the order Holtermanniales to accommodate tremellomycetous yeasts of the Holtermannia clade.
International journal of systematic and evolutionary microbiology. 04/2010; 61(Pt 3):680-9.
The novel genus Holtermanniella is proposed here to accommodate four Cryptococcus species closely related to Holtermannia corniformis that are included in the Holtermannia clade (Basidiomycota, Agaricomycotina). Thus, four novel combinations are proposed: Holtermanniella nyarrowii comb. nov., Holter... [more] The novel genus Holtermanniella is proposed here to accommodate four Cryptococcus species closely related to Holtermannia corniformis that are included in the Holtermannia clade (Basidiomycota, Agaricomycotina). Thus, four novel combinations are proposed: Holtermanniella nyarrowii comb. nov., Holtermanniella festucosa comb. nov., Holtermanniella mycelialis comb. nov. and Holtermanniella wattica comb. nov. In addition, a novel anamorphic yeast species was studied with 15 isolates obtained from different habitats around the world. Analysis of the sequences of the D1/D2 region of their large subunit rDNA showed that the novel species is placed phylogenetically within the Holtermannia clade of the Tremellomycetes (Agaricomycotina, Basidiomycota). PCR fingerprinting and sequencing of ITS1-5.8S-ITS2 showed genetic intraspecific variability among the strains: three groups were formed, which did not correlate with geographical origin or substrate. This novel species, designated the type species of Holtermanniella gen. nov., is described as Holtermanniella takashimae sp. nov.; the type strain is CBS 11174(T) (=HB 982(T) =DBVPG 8012(T)). The order Holtermanniales ord. nov. is proposed here to include Holtermannia (the type genus) and Holtermanniella.
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2.44Impact points
Polymorphism of viral dsRNA in Xanthophyllomyces dendrorhous strains isolated from different geographic areas.
Virology journal. 10/2009; 6(1):160.
ABSTRACT: BACKGROUND: Strains of the astaxanthin producing yeast Xanthophyllomyces dendrorhous have been isolated from different cold regions around the earth, and the presence of double stranded RNA (dsRNA) elements was described in some isolates. This kind of viruses is widely distributed among ye... [more] ABSTRACT: BACKGROUND: Strains of the astaxanthin producing yeast Xanthophyllomyces dendrorhous have been isolated from different cold regions around the earth, and the presence of double stranded RNA (dsRNA) elements was described in some isolates. This kind of viruses is widely distributed among yeasts and filamentous fungi and, although generally are cryptic in function, their studies have been a key factor in the knowledge of important fungi. In this work, the characterization and genetic relationships among dsRNA elements were determined in strains representatives of almost all regions of the earth where X. dendrorhous have been isolated. RESULTS: Almost all strains of X. dendrorhous analyzed carry one, two or four dsRNA elements, of molecular sizes in the range from 0.8 to 5.0 kb. Different dsRNA-patterns were observed in strains with different geographic origin, being L1 (5.0 kb) the common dsRNA element. By hybridization assays a high genomic polymorphism was observed among L1 dsRNAs of different X. dendrorhous strains. Contrary, hybridization was observed between L1 and L2 dsRNAs of strains from same or different regions, while the dsRNA elements of minor sizes (M, S1, and S2) present in several strains did not show hybridization with neither L1 or L2 dsRNAs. Along the growth curve of UCD 67-385 (harboring four dsRNAs) an increase of L2 relative to L1 dsRNA was observed, whiles the S1/L1 ratio remains constant, as well as the M/L1 ratio of Patagonian strain. Strains cured of S2 dsRNA were obtained by treatment with anisomycin, and comparison of its dsRNA contents with uncured strain, revealed an increase of L1 dsRNA while the L2 and S1 dsRNA remain unaltered. CONCLUSIONS: The dsRNA elements of X. dendrorhous are highly variable in size and sequence, and the dsRNA pattern is specific to the geographic region of isolation. Each L1 and L2 dsRNA are viral elements able to self replicate and to coexist into a cell, and L1 and S2 dsRNAs elements could be part of a helper/satellite virus system in X. dendrorhous.
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2.11Impact points
Cystobasidiomycetes yeasts from Patagonia (Argentina): description of Rhodotorula meli sp. nov. from glacial meltwater.
International journal of systematic and evolutionary microbiology. 10/2009;
The basidiomycetous yeast strain CRUB 1032, which formed salmon-pink colonies, was isolated from glacial meltwater in Patagonia, Argentina. Morphological, physiological and biochemical characterization indicated that this strain belonged to the genus Rhodotorula. Molecular taxonomic analysis based o... [more] The basidiomycetous yeast strain CRUB 1032, which formed salmon-pink colonies, was isolated from glacial meltwater in Patagonia, Argentina. Morphological, physiological and biochemical characterization indicated that this strain belonged to the genus Rhodotorula. Molecular taxonomic analysis based on the 26S rDNA D1/D2 domain and internal transcribed spacer (ITS) region sequences showed that CRUB 1032 represents an undescribed yeast species, for which the name Rhodotorula meli sp. nov. is here proposed (type strain: CBS 10797T=JCM 15319T). Phylogenetic analysis showed that R. lamellibrachii is the closest known species, together with which R. meli forms a separate cluster related to the Sakaguchia clade, within the Cystobasidiomycetes. Additional Patagonian yeast isolates of the Cystobasidiomycetes are also investigated in the present work.
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2.11Impact points
Cryptococcus spencermartinsiae sp. nov., a basidiomycetous yeast isolated from glacial waters and apple fruits.
International journal of systematic and evolutionary microbiology. 09/2009;
Seven strains representing a novel yeast species belonging to the genus Cryptococcus were isolated from different substrates from Patagonia Argentina and The Netherlands. Three strains were isolates from a meltwater river draining from the Frias glacier at Mount Tronador situated in Nahuel Huapi Nat... [more] Seven strains representing a novel yeast species belonging to the genus Cryptococcus were isolated from different substrates from Patagonia Argentina and The Netherlands. Three strains were isolates from a meltwater river draining from the Frias glacier at Mount Tronador situated in Nahuel Huapi National Park (Patagonia) and four were isolated from apple surfaces in Randwijk, The Netherlands. Analysis of the D1/D2 large-subunit and ITS rRNA sequence indicates that these strains represent a single species that is distinct from other species of the Tremellales clade. The name Cryptococcus spencermartinsiae is proposed to accommodate these strains. The type strain is CRUB 1230(T) (= CBS 10760(T)=DVPG 8010(T)).
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2.11Impact points
Cryptococcus agrionensis sp. nov., a basidiomycetous yeast of the acidic rock drainage ecoclade, isolated from acidic aquatic environment of volcanic origin (River Agrio, Argentina).
International journal of systematic and evolutionary microbiology. 09/2009;
Seventy-one strains, representing a novel species of the genus Cryptococcus, were isolated from the River Agrio-Lake Caviahue (RAC) acidic aquatic environment. Strains were isolated mainly from the most acid section of the river (pH 1.8 to 2.7). According to mini/microsatellite-primed PCR (MSP-PCR) ... [more] Seventy-one strains, representing a novel species of the genus Cryptococcus, were isolated from the River Agrio-Lake Caviahue (RAC) acidic aquatic environment. Strains were isolated mainly from the most acid section of the river (pH 1.8 to 2.7). According to mini/microsatellite-primed PCR (MSP-PCR) technique, and physiological data, these strains are a single species of the genus Cryptococcus. Analysis of the D1/D2 region of the large-subunit rRNA gene showed that the strains belong to the order Filobasidiales of the sub-phylum Agaricomycotina. Cryptococcus agrionensis formed a phylogenetic group with its closest related species: Cryptococcus ibericus, Cryptococcus aciditolerans and Cryptococcus metallitolerans. This group, which is phylogenetically related to the Gastricus clade, has been recently considered an ecoclade due to its peculiar ecology and physiology. The name Cryptococcus agrionensis is proposed to accommodate these strains. The strain CRUB 1317T=CBS 10799T=JCM 15321T was designated the type strain.
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2.11Impact points
Wickerhamomyces patagonicus sp. nov., an ascomycetous yeast species from Patagonia, Argentina.
International journal of systematic and evolutionary microbiology. 09/2009;
Eight strains of a novel yeast species were isolated from tree saps of Nothofagus dombeyi (Nothofagacea) and glacial meltwater (Castaño Overo River) in the Nahuel Huapi National Park (NHNP), Patagonia, Argentina. The sequences of the D1/D2 domains of the large subunit of the rRNA gene showed that th... [more] Eight strains of a novel yeast species were isolated from tree saps of Nothofagus dombeyi (Nothofagacea) and glacial meltwater (Castaño Overo River) in the Nahuel Huapi National Park (NHNP), Patagonia, Argentina. The sequences of the D1/D2 domains of the large subunit of the rRNA gene showed that this new yeast species belongs to the Wickerhamomyces clade. Its closest related species were Candida ponderosae and W. chambardii. The novel species, Wickerhamomyces patagonicus, is proposed to accommodate this new species, with the type strain CRUB 1724T (=CBS 11398 =JCM 16381).
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3.60Impact points
Yeasts from high-altitude lakes: influence of UV radiation.
FEMS microbiology ecology. 07/2009;
Abstract Mountain lakes located at a high elevation are typically exposed to high UV radiation (UVR). Little is known about the ecology and diversity of yeasts inhabiting these extreme environments. We studied yeast occurrence (with special emphasis on those producing carotenoid pigments) at five hi... [more] Abstract Mountain lakes located at a high elevation are typically exposed to high UV radiation (UVR). Little is known about the ecology and diversity of yeasts inhabiting these extreme environments. We studied yeast occurrence (with special emphasis on those producing carotenoid pigments) at five high-altitude (>1400 m a.s.l.) water bodies located in the Nahuel Huapi National Park (Bariloche, Argentina). Isolates were identified using a polyphasic approach. Production of photoprotective compounds (carotenoids and mycosporines) by yeast isolates, and UVB resistance of selected species were studied. All water samples contained viable yeast cells in variable numbers, generally ranging from 49 to 209 cells L(-1). A total of 24 yeast species was found; at least four represented novel species. Carotenogenic yeasts prevailed in lakes with low water conductivity and higher transparency and chlorophyll a levels. Apparently, the ability to produce photoprotective compounds in yeasts was related to the transparency of mountain lake waters, and strains from more transparent waters developed increased UVB resistance. Our results indicate that UVR is an important environmental factor affecting the yeast community structure in aquatic habitats.
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1.87Impact points
Photoprotective role of carotenoids in yeasts: Response to UV-B of pigmented and naturally-occurring albino strains.
Journal of photochemistry and photobiology. B, Biology. 04/2009;
In this work, the photoprotective role of carotenoids in yeasts was analysed by contrasting the responses to UV-B of pigmented and naturally occurring albino strains of Sporobolomyces ruberrimus and Cystofilobasidium capitatum in different conditions. Albino and pigmented strains were confirmed to b... [more] In this work, the photoprotective role of carotenoids in yeasts was analysed by contrasting the responses to UV-B of pigmented and naturally occurring albino strains of Sporobolomyces ruberrimus and Cystofilobasidium capitatum in different conditions. Albino and pigmented strains were confirmed to be conspecific by PCR fingerprinting and rDNA sequencing. Experimental exposure to UV-B conducted with both yeast species showed that the pigmented strains were more tolerant to UV-B than the albino strains and that the increment in carotenoid contents during the stationary growth phase enhance survivorship. These results indicated that carotenoid pigments afford UV-B protection in yeasts.
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2.11Impact points
Cystofilobasidium lacus-mascardii sp. nov., a basidiomycetous yeast species isolated from aquatic environments of the Patagonian Andes, and Cystofilobasidium macerans sp. nov., the sexual stage of Cryptococcus macerans.
International journal of systematic and evolutionary microbiology. 04/2009; 59(Pt 3):622-30.
Here, we report on two novel sexual basidiomycetous red yeast species of the genus Cystofilobasidium. Cystofilobasidium lacus-mascardii sp. nov. is based on sexually compatible strains isolated from Lake Mascardi, an ultraoligotrophic lake in north-western Patagonia, Argentina. Following the discove... [more] Here, we report on two novel sexual basidiomycetous red yeast species of the genus Cystofilobasidium. Cystofilobasidium lacus-mascardii sp. nov. is based on sexually compatible strains isolated from Lake Mascardi, an ultraoligotrophic lake in north-western Patagonia, Argentina. Following the discovery of the first isolate of this species, additional (sexually compatible) strains were isolated using a selective medium containing erythritol as the sole source of carbon. The second novel species corresponds to the sexual state of Cryptococcus macerans. In spite of accounts over the last 20 years of sexually compatible strains of this species, the complete life has never been observed. We provide evidence of a Cystofilobasidium-like basidial stage with teliospores and slender holobasidia, based on the study of self-fertile (homothallic) and self-sterile (heterothallic) isolates of Cryptococcus macerans. A revised molecular phylogeny of the genus Cystofilobasidium is presented and the most salient features of Cystofilobasidium lacus-mascardii sp. nov. (type strain CBS 10642(T) =PYCC 5819(T) =CRUB 1046(T)) and Cystofilobasidium macerans sp. nov. (type strain CBS 10757(T)) are discussed and compared with those of the remaining species in the genus. Information on additional Patagonian isolates belonging to the Cystofilobasidiales is also included in this report.
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3.60Impact points
Yeast diversity in the acidic Rio Agrio-Lake Caviahue volcanic environment (Patagonia, Argentina).
FEMS microbiology ecology. 07/2008;
The Rio Agrio and Lake Caviahue system (RAC), in Northwestern Patagonia, is a natural acidic environment. The aims of this study were to characterize the yeast community and to provide the first ecological assessment of yeast diversity of this extreme aquatic environment. Yeast occurrence and divers... [more] The Rio Agrio and Lake Caviahue system (RAC), in Northwestern Patagonia, is a natural acidic environment. The aims of this study were to characterize the yeast community and to provide the first ecological assessment of yeast diversity of this extreme aquatic environment. Yeast occurrence and diversity were studied at seven sites where the water pH varied between 1.8 and 6.7. Yeast CFU counts in the river ranged from 30 to 1200 CFU L(-1), but in the Lake the values were lower (30-60 CFU L(-1)). A total of 25 different yeast species were found, 11 of which belonged to undescribed taxa. Among these was an unusual strongly acidophilic Cryptococcus species. The RAC yeast community resembles that of acidic aquatic environments resulting from anthropic activities such as the São Domingos mines in Portugal and the Rio Tinto in Spain, respectively. The isolated yeast species were organized into different grades of adaptation to the RAC aquatic system. Based on the proposed grades, Rhodotorula mucilaginosa, Rhodosporidium toruloides and two novel Cryptococcus species were the most adapted species. These Cryptococcus species are apparently specialists of acidic aquatic environments, and might bear physiological features that possibly account for their ability to thrive in such extreme environments.
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1.32Impact points
Studies on the heterogeneity of the carotenogenic yeast Rhodotorula mucilaginosa from Patagonia, Argentina.
Journal of basic microbiology. 05/2008; 48(2):93-8.
The yeast species Rhodotorula mucilaginosa is considered to be ubiquitous due to its world-wide distribution in terrestrial, freshwater and marine habitats, and to its ability to colonize a large variety of substrates. In this paper we assess the phenotypic and genetic variability of environmental i... [more] The yeast species Rhodotorula mucilaginosa is considered to be ubiquitous due to its world-wide distribution in terrestrial, freshwater and marine habitats, and to its ability to colonize a large variety of substrates. In this paper we assess the phenotypic and genetic variability of environmental isolates of R. mucilaginosa collected from natural and artificial environments in Patagonia, Argentina. A total of 97 strains were studied and sorted into three groups based on MSP-PCR fingerprinting results: A, which comprised 90% of the strains, including the type strain; and B and C which included 2 and 8% of the strains, respectively. The D1D2 sequencing did not differentiate any of the 3 groups, while ITS sequencing validated the existence of group C. This group was composed of Patagonian isolates of diverse origin. DNA-DNA reassociation studies confirmed the existence of significant genetic differences between group C and the type strain. In this study, which is the first on the intraspecific variability of a large set of R. mucilaginosa isolates, a considerable phenotypic and genetic heterogeneity was observed, however such differences were not enough to refute co-specificity. The study of Patagonian isolates allowed the detection of a genetically distinct group of R. mucilaginosa strains.
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1.80Impact points
Characterization of a novel South American population of the astaxanthin producing yeast Xanthophyllomyces dendrorhous (Phaffia rhodozyma).
Journal of industrial microbiology & biotechnology. 04/2008; 35(3):151-8.
A novel population of the biotechnologically important yeast Xanthophyllomyces dendrorhous, the sexual stage of Phaffia rhodozyma, has been recently isolated for the first time in the southern Hemisphere (Patagonia, Argentina). The aim of the present work was to phenotypically and genotypically char... [more] A novel population of the biotechnologically important yeast Xanthophyllomyces dendrorhous, the sexual stage of Phaffia rhodozyma, has been recently isolated for the first time in the southern Hemisphere (Patagonia, Argentina). The aim of the present work was to phenotypically and genotypically characterize two representative strains of this new population, and assess such strains as a potential biotechnological source of astaxanthin, fatty acids and extracellular enzymes. Minor variations were found in physiological tests. PCR fingerprinting studies (MSP-PCR) showed the main differences between X. dendrorhous Patagonian and Type strains. Patagonian strains accumulated a xanthophyll-like pigment, which was identified as astaxanthin. These strains showed low fatty acids content (mainly polyunsaturated fatty acids) and, of a total of six extracellular enzymes tested, only produced amylase. Genetic differences between Patagonian and collection X. dendrorhous strains could be explained by geographic isolation and habitat specificity.
Following (5)
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Pietro Buzzini
Università degli Studi di Perugia -
Teun Boekhout
Koninklijke Nederlandse Akademie van Wetenschappen -
Matilda Olstorpe
Sveriges Lantbruksuniversitet -
Arja Laitila
VTT Technical Research Centre of Finland
