Diversity and affinities among species and strains of Lipomyces

Phylogenetic relationships of the yeast genus Lipomyces were studied using sequences from fragments of 5.8S rRNA gene and from internal transcribed spacer region ITS2 of 13 strains (7 type strains included) representing five species and subtaxa, and originating from different geographical locations (Japan, Trinidad, Nigeria, North America, Western Europe, Russia, South Africa, Mauritius). Parsimony and distance analyses were performed. Tree topology from the parsimony and distance analyses of the sequence confirmed the results of nDNA reassociation. Results segregate the 13 isolates of Lipomyces into five major clades.(Au)

Diversity and affinities among species and strains of Lipomyces.

Phylogenetic relationships of the yeast genus Lipomyces were studied using sequences from fragments of 5.8S rRNA gene and from internal transcribed spacer region ITS2 of 13 strains (7 type strains included) representing five species and subtaxa, and originating from different geographical locations (Japan, Trinidad, Nigeria, North America, Western Europe, Russia, South Africa, Mauritius). Parsimony and distance analyses were performed. Tree topology from the parsimony and distance analyses of the sequence confirmed the results of nDNA reassociation. Results segregate the 13 isolates of Lipomyces into five major clades.

The application of whole-cell protein electrophoresis for the classification and identification of basidiomycetous yeast species.

The relationships among 65 basidiomycetous yeast strains were determined by one-dimensional electrophoresis of SDS-solubilized whole-cell proteins. Protein profiles were compared by the Pearson product moment correlation coefficient (r). The strains investigated represented species from the genera Cystofilobasidium, Filobasidium, Filobasidiella, Kondoa, Leucosporidium, Mrakia and Rhodosporidium. Except for the genus Mrakia, all species constituted separate protein electrophoretic clusters. The species of the genus Mrakia (M. frigida, M. gelida, M. nivalis and M. stokesii) show highly similar protein patterns, suggesting that these four species may be synonymous. Strains of two varieties of Filobasidiella neoformans, F. neoformans var. neoformans and F. neoformans var. bacillispora, could not be differentiated by protein electrophoresis. For the delineation of the protein electrophoretic clusters of the yeasts studied, literature data relying on other criteria, such as DNA base composition, carbon source utilization patterns, enzymatic protein electrophoregrams, ubiquinone systems, DNA-DNA homology and rRNA sequence data were used. It was demonstrated that a database of SDS-protein patterns provides a valuable tool for the identification of yeasts.

Phylogenetic analysis of five medically important Candida species as deduced on the basis of small ribosomal subunit RNA sequences.

The classification of species belonging to the genus Candida Berkhout is problematic. Therefore, we have determined the small ribosomal subunit RNA (srRNA) sequences of the type strains of three human pathogenic Candida species; Candida krusei, C. lusitaniae and C. tropicalis. The srRNA sequences were aligned with published eukaryotic srRNA sequences and evolutionary trees were inferred using a matrix optimization method. An evolutionary tree comprising all available eukaryotic srRNA sequences, including two other pathogenic Candida species, C. albicans and C. glabrata, showed that the yeasts diverge rather late in the course of eukaryote evolution, namely at the same depth as green plants, ciliates and some smaller taxa. The cluster of the higher fungi consists of 10 ascomycetes and ascomycete-like species with the first branches leading to Neurospora crassa, Pneumocystis carinii, Candida lusitaniae and C. krusei, in that order. Next there is a dichotomous divergence leading to a group consisting of Torulaspora delbrueckii, Saccharomyces cerevisiae, C. glabrata and Kluyveromyces lactis and a smaller group comprising C. tropicalis and C. albicans. The divergence pattern obtained on the basis of srRNA sequence data is also compared to various other chemotaxonomic data.

Structuring strain data for storage and retrieval of information on fungi and yeasts in MINE, the Microbial Information Network Europe.

A distributed Microbial Information Network Europe (MINE) is being constructed by a number of major microbial culture collections in countries of the European Community, with the support of the Biotechnology Action Programme (BAP) of the Commission of the European Community. The representatives of the collections participating in MINE have agreed to adopt a general format for the computer storage and retrieval of strain data. This uniform format will facilitate the electronic combination and exchange of data from different collections in order to produce integrated catalogues and the use of identical commands to search the different databases. It is recommended to other collections who may wish to contribute data to the MINE network or between themselves. Three kinds of records can be linked to the leading 'species records': strain records, synonym records, and alternative morphonym records. A minimum data set of 30 fields (similar to the fields used for producing catalogues) is defined that facilitates the exchange of data between the national nodes and serves as a directory to strains available at other nodes. It is suggested that the full strain record comprise 99 fields, grouped in 12 blocks: internal administration--name--strain administration--status--environment and history--biological interactions--sexuality--properties (cytology, biomolecular data)--genotype and genetics--growth conditions--chemistry and enzymes--practical applications. Several fields are divided into subfields of different ranks. Delimiters are used either to separate a range of entries that have to be indexed or to divide an entry from the reference to its source or remarks that should not be indexed. The contents and structure of the fields proposed for filamentous fungi and yeasts are described and in some cases illustrated by examples. Uniformity of input is essential for indexed fields and desirable for non-indexed fields. Seven thesaurus files are envisaged to ensure consistency.