Biomedical subjects

Wladyslav I Golubev

Publications and source records attributed to Wladyslav I Golubev.

12 recordsLinked to original sources

PubMed2006

Cryptococcus stepposus, a new filobasidiaceous yeast species found in the Prioksko-terrasny biosphere reserve in Russia.

Mycocinotyping of cryptococci from the Prioksko-terrasny reserve (Russia) has revealed three strains that have a unique mycocin-sensitivity profile. Sequencing results of the D1/D2 domain of the 26S rDNA and of the complete ITS region placed them in the Floriforme clade of the Filobasidiales lineage (Hymenomycetes). The three strains had identical sequences, which differed from those of known Filobasidium and Cryptococcus species. A novel species named Cryptococcus stepposus (type strain VKM Y-2918) is proposed to accommodate these isolates. Physiological characteristics distinguishing the novel species from other Cryptococcus species in the Floriforme clade are presented.

Cryptococcus↗

PubMed2006

Mycocin production in Pseudozyma tsukubaensis.

Killer activity expressed at pH values ranging from 3.5 to 6.0 was found in the ustilaginaceous yeast-like species, Pseudozyma tsukubaensis. Its killer phenotype was incurable, and extrachromosomal genetic elements were not detected. The toxin excreted with a molecular mass above 15 kDa is fungicidal, resistant to proteolytic cleavage, thermolabile and active only against fungi within the Ustilaginomycetes (the orders Microstromatales and Ustilaginales).

Mycotoxins↗

PubMed2005

Cryptococcus silvicola nov. sp. from nature reserves of Russia and Portugal.

Nitrate-positive strains of a filobasidiaceous anamorphic yeast related to Cryptococcus cylindricus were isolated from forest litter in a Russian nature reserve and from a lichen in Portuguese one. Mycocinotyping and rDNA sequence analysis revealed that the strains represent a novel species, for which the name Cryptococcus silvicola (type strain VKM Y-2939=CBS 10099) is proposed.

Base Sequence↗

PubMed2005

Ustilagic acid secretion by Pseudozyma fusiformata strains.

Eight strains of Pseudozyma fusiformata were examined for antifungal activity. All of them had the same spectrum of action and were active against many species of yeasts, yeast-like and filamentous fungi. They secreted glycolipids, which were purified from the culture liquid by column and thin-layer chromatography. According to nuclear magnetic resonance and mass-spectroscopy experiments all strains produced ustilagic acid, a cellobioside-containing 2,15,16-trihydroxypalmitic acid as aglycon, 3-hydroxycaproic acid and acetic acid as O-acylic substituents.

Antifungal Agents↗

PubMed2004

Mycocin production in Cryptococcus aquaticus.

Double-stranded RNA viruses of about 35 nm in diameter were isolated from a mycocin-secreting strain of Cryptococcus aquaticus. A derivative of this strain, lacking small dsRNA, was non-mycocinogenic and sensitive to its own toxin. The killing pattern of this mycocin was restricted to some species of the Cystofilobasidiales clade. Despite the differences in genome size of dsRNA viruses in mycocinogenic strains of Cryptococcus aquaticus, Cystofilobasidium sp. CBS 6569, Cystofilobasidium bisporidii, Cystofilobasidium infirmominiatum, Trichosporon pullulans and Xanthophyllomyces dendrorhous and killing patterns of their mycocins, the viral genomes showed homology in hybridisation experiments.

Cryptococcus↗

PubMed2004

Characterization of an antifungal glycolipid secreted by the yeast Sympodiomycopsis paphiopedili.

An antifungal glycolipid was purified from the culture liquid of the ustilaginomycetous yeast Sympodiomycopsis paphiopedili by column and thin-layer chromatography. According to nuclear magnetic resonance and mass-spectroscopy experiments it was a cellobioside containing 2,15,16-trihydroxypalmitic acid as an aglycon. The minimal effective concentrations leading to ATP leakage and growth inhibition were 45 and 160 microg ml(-1) for Cryptococcus terreus and Candida albicans, respectively.

Adenosine Triphosphate↗

PubMed2004

Curvibasidium cygneicollum gen. nov., sp. nov. and Curvibasidium pallidicorallinum sp. nov., novel taxa in the Microbotryomycetidae (Urediniomycetes), and their relationship with Rhodotorula fujisanensis and Rhodotorula nothofagi.

Strains of Rhodotorula fujisanensis (Basidiomycota, Urediniomycetes, Microbotryomycetidae), including the type strain, are sexually compatible and produce clamped mycelium with teliospores. However, as teliospore germination had not been documented, the complete sexual cycle was not known. During the course of this work, the basidial stage of R. fujisanensis was characterized. In addition, mating studies employing isolates that were identified preliminarily as Rhodotorula nothofagi, a species that is related closely to R. fujisanensis, yielded mycelium with teliospores, which formed basidia and basidiospores. The new data were evaluated by using several criteria, including the available molecular phylogenetic framework for the Microbotryomycetidae. Curvibasidium gen. nov. is described here, to accommodate two teleomorphs: Curvibasidium cygneicollum sp. nov. (CBS 4551T), which is described as the sexual stage of R. fujisanensis, and Curvibasidium pallidicorallinum sp. nov. (CBS 9091T), which is related closely to R. nothofagi, but does not represent its sexual stage.

Basidiomycota↗

PubMed2004

Cryptococcus festucosus sp. nov. a new hymenomycetous yeast in the Holtermannia clade.

Five yeast strains belonging to the genus Cryptococcus Vuillemin were isolated from steppe plants and turf collected in the Prioksko-terrasny biosphere reserve (Moscow region, Russia). Sequence analyses of the D1/D2 domains of the 26S rDNA and of the internal transcribed spacer region revealed that these yeast strains and strain CBS 8016 have almost identical sequences and belong to the Holtermannia clade of the Tremellomycetidae (Basidiomycota, Hymenomycetes). A novel species named Cryptococcus festucosus (type strain VKM Y-2930) is proposed to accommodate these strains. Physiological characteristics and mycocin sensitivity patterns distinguishing Cryptococcus festucosus from the other species of this clade are presented.

Antifungal Agents↗

PubMed2004

Cryptococcus paraflavus sp. nov. (Tremellales), isolated from steppe plants in Russia.

Three strains related to Cryptococcus flavus were isolated from plants collected in the Prioksko-terrasny biosphere reserve (Russia). Physiological characterization, mycocinotyping, sequencing of the D1/D2 domain of the 26S rDNA and the ITS region revealed their separate taxonomic position. The name Cryptococcus paraflavus is proposed to accommodate these isolates (type strain VKM Y-2923).

Cryptococcus↗

PubMed2003

Double-stranded RNA viruses in a mycocinogenic strain of Cystofilobasidium infirmominiatum.

The viral particles (about 30 nm in diameter) that contain dsRNAs (2.0 and 6.3 kbp) encapsidated by a coat of protein were detected in a mycocin-secreting strain of Cystofilobasidium infirmominiatum isolated from plants in an oak forest (Moscow region). The mycocin with a molecular mass above 15 kDa is fungicidal (maximum activity at pH 4.5) and active mainly against some species of the Cystofilobasidiales and Filobasidiales ('Cryptococcus aerius' clade). Curing by incubation at elevated temperature resulted in the concomitant loss of dsRNAs and mycocinogenic activity, and cured derivatives became sensitive to the mycocin produced by the parent strain.

Basidiomycota↗

PubMed2003

ATP leakage from yeast cells treated by extracellular glycolipids of Pseudozyma fusiformata.

The ustilaginaceous yeast Pseudozyma fusiformata secreted glycolipids which were lethal to many yeasts and fungi more active at pH of about 4.0, and in the temperature range of 20-30 degrees C. Purified glycolipids enhanced non-specific permeability of the cytoplasmic membrane in sensitive cells, which resulted in ATP leakage and susceptibility of the cells to staining with bromocresol purple. Cells of Saccharomyces cerevisiae lost the ability to acidify the medium. Basidiomycetous yeasts were more sensitive to the glycolipids than ascomycetous ones. The minimal effective glycolipid concentration was 0.13 and 0.26 mg ml(-1) for Cryptococcus terreus and Filobasidiella neoformans, while for Candida albicans and Saccharomyces cerevisiae it was 1.0 and 1.6 mg ml(-1).

Adenosine Triphosphate↗

PubMed2003

Cryptococcus nemorosus sp. nov. and Cryptococcus perniciosus sp. nov., related to Papiliotrema Sampaio et al. (Tremellales).

Three mycocinogenic strains representing the genus Cryptococcus were isolated on glucuronate agar from plants and turf collected in the Prioksko-terrasny biosphere reserve (Russia). These isolates fit the standard description of Cryptococcus laurentii, but differ from its type strain in both their mycocin-sensitivity profiles and the killing patterns of their mycocins. Sequence analyses of the D1/D2 domain of the 26S rDNA and of the internal transcribed spacer region confirmed that these isolates represent two novel species, for which the names Cryptococcus nemorosus sp. nov. (type strain VKM Y-2906(T)) and Cryptococcus perniciosus sp. nov. (type strain VKM Y-2905(T)) are proposed. Morphological, physiological and biochemical characteristics, as well as mycocinotyping and molecular analysis, show a close affinity between these two novel anamorphic species and the teleomorphic species Papiliotrema bandonii (Tremellales).

Basidiomycota↗