Rhodotorula grinbergsii sp. nov. isolated from decayed wood in the evergreen rainy Valdivian forest of southern Chile

An unusual Rhodotorula isolated from decayed wood of Eucryphia cordifolia Cav. is described and illustrated. This species differs enough from all accepted Rhodotorula species (1–5) to warrant its establishment as a new species, Rhodotorula grinbergsii sp. nov.The DNA base composition of this species was not calculated, since our laboratory is not properly equipped for that purpose.     

Rhodotorula nothofagi sp. nov., isolated from decayed wood in the evergreen rainy Valdivian forest of southern Chile

An unusual Rhodotorula isolated from decayed wood of Nothofagus obliqua (Mirb.) Blume is described and illustrated. This species differs from all accepted Rhodotorula species (1–7, 10) to warrant its establishment as a new species, Rhodotorula nothofagi sp. nov.Postgraduate student from the Instituto de Ecología y de Evolución, Universidad Austral de Chile, Valdivia.     

Species ofRhodotorula isolated from laryngeal swabs

Summary Three species of the genusRhodotorula were isolated from laryngeal swabs. A new species,Rhodotorula laryngis, is described. The technical assistance of MissAnna Helgerud is gratefully acknowledged.     

Cytological and chemical changes in cell walls ofRhodotorula gracilis

The phenotype and genotype of six strains of the genusRhodotorula Harrison and of one strain of the genusCryptococcus Phaff et Fell, with anomalous thickening of cell walls were investigated. The present studies showed that the strains investigated represent different stages of the life cycles of the genusRhodosporidium Banno. The anomalous thickening of the cell walls can be explained by extreme conditions resulting in the formation of surviving forms (teliospores, chlamydospores).     

In Vitro Interactions of Amphotericin B Combined with Non-antifungal Agents Against Rhodotorula mucilaginosa Strains

Rhodotorula species are emerging as opportunistic pathogens, causing catheter-associated fungemia in patients with compromised immunity. R. mucilaginosa is considered the most common species involved in human infections. Correct identification and susceptibility testing of Rhodotorula isolates recovered from the blood stream or central nervous system are essential to determine the best management of this unusual infection. The antifungal susceptibility tests showed that Rhodotorula was susceptible to low concentrations of amphotericin B (AMB) but was less susceptible to voriconazole. Combinations of AMB plus several non-antifungal medications were evaluated against 35 susceptible (Rm AMB-S) and resistant (Rm AMB-R) clinical Rhodotorula isolates using the broth microdilution checkerboard technique. We showed that in vitro exposure to increasing concentrations of AMB changed the susceptibility profile to these strains, which were named the Rm AMB-R group. The most synergistic interactions were AMB?+?simvastatin, followed by AMB?+?amlodipine and AMB?+?warfarin. Synergism and antagonism were observed in both groups for the combination AMB?+?cyclosporine A. AMB combined with a fluoroquinolone (AMB?+?levofloxacin) also demonstrated antagonism for the Rm AMB-S strains, but a high percentage of synergistic interactions was observed for the Rm AMB-R group. A combination drug approach can provide a different strategy to treat infections caused by AMB-resistant R. mucilaginosa.

     

Two new yeasts from Hawaiian fruit flies

Summary One yeast isolate from the feces of the fruit flyD. crucigera is new and is described asCandida sorbosa nov. sp. A new species ofRhodotorula from the living larva ofDrosophila pilimanae is described asRhodotorula pilimanae.Supported in part by a grant-in-aid from the Graduate School, Illinois Institute of Technology.     

Two new species of the genus Sporobolomyces and a new Rhodotorula species from leaf surfaces

Two new species of the genus Sporobolomyces and one of the genus Rhodotorula are described. Sporobolomyces elongatus and Rhodotorula armeniaca spp. nov. were isolated from the surfaces of leaves of Callistemon viminalis (Soland ex Gaertn.) G. Don ex Loud. and Sporobolomyces foliicola from the leaves of Banksia collina R. Br. growing at Armidale.     

Repellent,Insecticidal and Antimicrobial Activities of Leaf Essential Oils from Three Eucalyptus Species

Developing effective and eco‐friendly antimicrobials and pesticides has become a highly important issue. The repellent, insecticidal and antimicrobial activity of essential oils (EOs) isolated by hydrodistillation from dried leaves of the three Eucalyptus species (E. cloeziana, E. umbellata and E. benthamii) were investigated. During GC/MS analysis, α‐pinene (47.36 %), 1,8‐cineol (38.53 %) and α‐pinene (35.31 %) were identified as major components of E. cloeziana, E. umbellata and E. benthamii, respectively. The EOs from E. cloeziana exhibited the longest effective protection time (465 min, at 50.0 % w/w) for humans among the EOs studied. The effective protection time was 30 min and 300 min at concentrations of 12.5 % (w/w) and 25.0 % (w/w), respectively. Fumigating insecticidal activity of EOs from three Eucalyptus species was tested by airtight fumigation in conical flask, which indicated that essential oils had a highly and rapidly insecticidal activity on Culex pipiens quinquefasciatus. The antimicrobial activity of EOs was evaluated by using disc diffusion and agar dilution methods. There was no significant difference in the antibacterial activity of EOs from E. cloeziana and E. umbellate and they had the same MICs (20 mL/L) on Staphylococcus aureus, Salmonella typhi, Bacillus subtilis and Escherichia coli. E. benthamii had the worst microbial inhibitory effect among the three Eucalyptus essential oils and the MIC value for the test species is 40 mL/L except for Rhodotorula Harrison (10 mL/L).     

Carotenoids from <Emphasis Type="Italic">Rhodotorula</Emphasis> and <Emphasis Type="Italic">Phaffia</Emphasis>: yeasts of biotechnological importance

Carotenoids represent a group of valuable molecules for the pharmaceutical, chemical, food and feed industries, not only because they can act as vitamin A precursors, but also for their coloring, antioxidant and possible tumor-inhibiting activity. Animals cannot synthesize carotenoids, and these pigments must therefore be added to the feeds of farmed species. The synthesis of different natural commercially important carotenoids (β-carotene, torulene, torularhodin and astaxanthin) by several yeast species belonging to the genera Rhodotorula and Phaffia has led to consider these microorganisms as a potential pigment sources. In this review, we discuss the biosynthesis, factors affecting carotenogenesis in Rhodotorula and Phaffia strains, strategies for improving the production properties of the strains and directions for potential utility of carotenoid-synthesizing yeast as a alternative source of natural carotenoid pigments.     

The yeast genus Yarrowia gen. nov.

The ascigerous teleomorph of Candida lipolytica (Harrison) Diddens et Lodder, previously classified as Endomycopsis lipolytica Wickerham et al. and as Saccharomycopsis lipolytica (Wickerham et al.) Yarrow, has been assigned to the new genus Yarrowia. Yarrowia lipolytica (Wickerham et al.) comb. nov. is the type species for the genus.The remaining species of Saccharomycopsis are revised.     

Distribution and identification of red yeasts in deep-sea environments around the northwest Pacific Ocean

We isolated 99 yeast strains, including 40 red yeasts, from benthic animals and sediments collected from the deep-sea floor in various areas in the northwest Pacific Ocean. Comparing the yeast isolates from animals and sediments collected from shallow locations, the proportion of red yeasts differed considerably, comprising 81.5% and 10.6% of the isolates from animals and sediments, respectively. All of the red yeast isolates belonged to the genera Rhodotorula and Sporobolomyces. On the basis of morphological and physiological characteristics, the isolates were identified as R. aurantiaca, R. glutinis, R. minuta and R. mucilaginosa of the genus Rhodotorula, and S. salmonicolor and S. shibatanus of the genus Sporobolomyces. Only R. glutinis and R. mucilaginosa were isolated from sediments. All of the others were isolated from animal sources. Phylogenetic analyses based on internal transcribed spacer (ITS) regions and 5.8S rRNA gene sequences allowed us to establish the precise taxonomic placement of each of the isolates and thereby investigate the intraspecific relationships among the isolates. Twenty-two strains identified as members of R. glutinis, which showed a wide distribution in the deep-sea, and five isolates identified as R. minuta, which were isolated only from benthic animals, showed substantial heterogeneity within the species. The isolates phenotypically identified as Sporobolomyces species and R. mucilaginosa phylogenetically occupied the placements corresponding to these species. Some strains assigned to known species on the basis of phenotypic features should be regarded as new species as suggested by the results of molecular analysis.     

<Emphasis Type="Italic">Rhodotorula oryzae</Emphasis> sp. nov., a novel basidiomycetous yeast species isolated from paddy rice

A basidiomyetous yeast strain RO-203, which formed orange-red colored colonies, was isolated from a sample of paddy rice crops at the ripe stage in Japan. 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 RO-203 represents an undescribed yeast species, for which the name Rhodotorula oryzae sp. nov. is proposed (type strain: AS 2.2363^T = MAFF 516128^T). The new species clustered in a branch together with Sakaguchia dacryoidea in phylogenetic trees based on the D1/D2 and ITS sequences. These two species differed by 2.3% and 12% nucleotide divergences in the D1/D2 and ITS regions, respectively.     

Microbiological Characteristics and Susceptibility Patterns of Strains of Rhodotorula Isolated from Clinical Samples

The members of the genus Rhodotorula show a marked ubiquity. In man, they have been isolated from faeces, nails, skin, sputum, digestive tract and adenoids, forming part of the normal human flora, although in recent years cases have been reported of both local and systemic infection by this yeast. There are virtually no studies in the literature on the sensitivity of this genus to the antifungal agents in common clinical use. Therefore, it is considered of interest to study the microbiological characteristics and the susceptibility patterns of Rhodotorula isolated from clinical samples. A total of 35 different strains of Rhodotorula were studied. In vitro susceptibility testing to 5-fluorocytosine, amphotericin B, ketoconazole, fluconazole and itraconazole was performed. All the strains were considered sensitive to 5-fluorocytosine, amphotericin B, ketoconazole and itraconazole and resistant to fluconazole. As a conclusion, we can state that all the antifungal agents tested, except fluconazole, are useful medicaments for the treatment of infections by the Rhodotorula genus. This revised version was published online in June 2006 with corrections to the Cover Date.     

Rhodotorula himalayensis sp. nov., a novel psychrophilic yeast isolated from Roopkund Lake of the Himalayan mountain ranges, India

Twenty-five psychrophilic yeasts were isolated from the soil of Roopkund Lake, Himalayas, India. Two colony morphotypes were identified and representatives of ‘morphotype 1’ were identified as Cryptococcus gastricus. Representatives of ‘morphotype 2’, namely 3A^T, 4A, 4B and Rup4B, showed similar phenotypic properties and are identical with respect to the nucleotide sequence of the ITS1-5.8S rRNA gene-ITS2 region and D1/D2 domain of the 26S rRNA gene. The sequence of D1/D2 domain of 3A^T shows 97.6–98.8% similarity with Rhodotorula psychrophila CBS10440^T, Rhodotorula glacialis CBS10437^T and Rhodotorula psychrophenolica CBS10438^T and in the neighbour-joining phylogenetic tree strains; 3A^T, 4A, 4B and Rup4B form a cluster with Rhodotorula glacialis and Rhodotorula psychrophila. Strains 3A^T, 4A, 4B and Rup4B also differ from their nearest phylogenetic relatives in several biochemical characteristics such as in assimilation of d-galactose, l-sorbose, maltose, citrate, d-glucuronate and creatinine. Thus, based on the phylogenetic analysis and the phenotypic differences 3A^T, 4A, 4B and Rup 4B are assigned the status of a new species of Rhodotorula for which the name Rhodotorula himalayensis sp. nov. is proposed with 3A^T as the type strain (=CBS10539^T =MTCC8336^T). GenBank/EMBL accession numbers for (partial) 18SrRNA gene-ITS1-5.8S rRNA gene-ITS2-26S rRNA gene (partial) sequences of Rhodotorula himalayensis sp. nov. 3A^T is AM410635.     

Airborne yeasts in Amritsar (India)

A survey of airborne yeasts in Amritsar has been carried out by the petri plate exposure method for a period of one year. A total of 14 yeasts species appeared on the plates. Candida was the commonest yeast representing 43.1% of the total colony count followed by Rhodotorula and Torulopsis. There was a seasonal variation in the concentration of the yeasts in the atmosphere. Maximal numbers were recorded in October and minima during January–February.     

Characterization of yeast and filamentous fungi isolated from cryoconite holes of Svalbard,Arctic

Cryoconite holes have biogeochemical, ecological and biotechnological importance. This communication presents results on culturable psychrophilic yeast and filamentous fungi from cryoconite holes at Midre Lovénbreen glacier. The identification of these microbes was achieved through conventional and DNA sequencing techniques. Effect of temperature, salt and media on growth of the cultures was studied. Measurements on the bioavailability of nutrients and trace metals were made through different methods including ICPMS (Inductively Coupled Plasma Mass Spectrometry). Colony forming unit (CFU) per gram of sediment sample was calculated to be about 7 × 10³–1.4 × 10⁴ and 4 × 10³–1.2 × 10⁴ of yeast and filamentous fungi, respectively. Based on morphology and sequence data, these were identified as Cryptococcus gilvescens, Mrakia sp., Rhodotorula sp., Phialophora alba and Articulospora tetracladia. Amongst these, Phialophora alba, Cryptococcus gilvescens and Mrakia sp. zhenx-1 are reported for the first time from Svalbard Arctic, while Rhodotorula sp. (95% gene similarity) is a new species, yet to be described. Rhodotorula sp. expressed high amylase, while Cryptococcus gilvescens showed high lipase activity. Mrakia sp. showed phosphate solubilization between 4 and 15°C, which is a first record. Chemical analysis revealed the presence of organic carbon, nitrogen and phosphorus in substantial amounts in the sediments. Filamentous fungi and yeast in the cryoconite holes drive the process of organic macromolecule degradation through cold-adapted enzyme secretion, thereby assisting in nutrient cycling in these subglacial environments. Further, these cold-adapted enzymes may provide an opportunity for the prospect of biotechnology in Arctic. This is the first report on mycological investigation into cryoconite holes from Midre Lovénbreen glacier.     

A New Mint (Variety of Mentha aquatica L.) Containing (—)-Isopinocamphone as a Major Constituent of Essential Oil

Certain strains of Rhodotorula were found capable of utilizing L-phenylalanine as a sole carbon and nitrogen source and of accumulating ether-soluble metabolite in the cultured broth. The metabolite was isolated and identified as trans-cinnamic acid. The nonoxidative deamination of phenylalanine to trans-cinnamic acid was catalyzed by dried cells, acetone-dried cells or intact cells with surface active agents. The distribution of phenylalanine ammonia-lyase activity in yeasts was investigated. It was found that the enzyme activity specifically occurred in Rhodotorula and that the formation of enzyme was enhanced by culturing on the medium supplemented with phenylalanine.     

The numbers of yeasts associated with wine grapes of Bordeaux

Summary A few days before vintage, yeasts were isolated quantitatively from three varieties of wine grape from three châteaux of the Graves region of the Gironde. There were about 10⁵ viable yeasts/g of grape, from which only Kloeckera apiculata, Metschnikowia pulcherrima and one or more species of Rhodotorula were isolated.     

On the existence of H+-symport in yeasts

34 yeast strains representing 22 species and two varieties were investigated for the existence of a proton-sugar symport. The changes in pH of unbuffered cell suspensions on the addition of alkali, acid, transportable sugars and uncouplers were recorded. Responses indicating the existence of an energy dependent proton extrusion and H⁺-sugar symport were found in most cases, particularly in Rhodotorula but rarely in Saccharomyces species. Remarkable differences were found among strains belonging to the same species.List of Abbreviations DNP 2,4-dinitrophenole - CCCP carbonyl cyanide m-chlorophenyl hydrazone     

Endophytic yeast fungi in plant storage tissues

It was found that plant storage tissues (fleshy sugar-containing fruits, subsurface metamorphically altered plant organs (storage roots, tubers, etc.), and starch-containing seed lobes) nearly always contain yeasts that are able to actively reproduce in these tissues causing no visible damage. Within storage tissues, yeast cells were detected both in the intercellular space and inside plant cells. In the tissues of fleshy fruits, endophytic yeasts are represented by the same species as epiphytic ones; cryptococci of the order Filobasidiales and ascomycetes belonging to the genera Hanseniaspora and Metschnikowia are predominant. In subsurface plant organs, red pigmented basidiomycetous yeasts of the genus Rhodotorula prevail. Selective growth of representatives of one species, Candida railenensis, is typical of starch-containing storage tissues of seeds. The results obtained change the established notion of the distributional patterns of yeast fungi in natural habitats and suggest that internal storage tissues of plants can be considered as a new interesting model for studies of coevolving plant-microbial associations.