Abstract:
Septal pore ultrastructure of selected species of basidiomycetous yeasts was observed. Rhodosporidium dacryoidum and Leucosporidium fellii of the teliospore-forming yeasts have simple septal pores, whereas those of Mrakia frigida and Cystofilobasidium infirmominiatum of the Filobasidiaceae possess dolipores without parenthesomes. In Erythrobasidium hasegawianum and Kondoa malvinella, also of the Filobasidiaceae, the septa are simple, uniperforate, and associated with pore occlusions. Erythrobasidium hasegawianum has the septal pore structure typical of members of Rhodosporidium and related genera in the teliospore-forming yeasts, whereas K. malvinella has septal pores similar to those of Atractogloea stillata (Atractiellales). In addition to these features, E. hasegawianum is characterized by the multilayered cell wall structure and enteroblastic conidiogenesis typical of basidiomycetous yeasts. Sympodiomycopsis paphiopedili, a yeast-like anamorph with basidiomycetous nature, has a simple septal pore structure suggesting a possible affinity with the teliospore-forming yeasts. Comparisons between the ultrastructural. morphological and chemosystematic evidence are made, and the taxonomic decisions of recent years are discussed.

Keywords:
BASIDIOMYCETOUS YEASTS, PHYLOGENY, SEPTAL PORE, SYSTEMATICS, ULTRASTRUCTURE

Addresses:
UNIV TOKYO, INST APPL MICROBIOL, YAYOI 1-1-1, BUNKYO KU, TOKYO 113, JAPAN.

Keywords:
BASIDIOMYCETOUS YEASTS, PHYLOGENY, SEPTAL PORE, SYSTEMATICS, ULTRASTRUCTURE

Addresses:
UNIV TOKYO, INST APPL MICROBIOL, YAYOI 1-1-1, BUNKYO KU, TOKYO 113, JAPAN.

Abstract:
Estimates of the nuclear DNA (nDNA) content in the yeast cells of 43 strains of Leucosporidium scottii, Rhodosporidium toruloides, and related yeast taxa were analyzed by fluorescence microscope photometry. Quantitative differences of nDNA contents occur among 18 strains of L. scottii. Four groups of strains with similar nDNA content were recognizable in L. scottii. One group contained only one strain (IFO 9474) which was characterized by the Q-7 system. The respective strains of the remaining three groups had either Q-9 or Q-10 as the major ubiquinone system, except CBS 8188 having both of these. Some mating strains of L. scottii had almost twice the amount of nDNA as the presumed haploid value. In contrast, both mating type A and a strains of R. toruloides had nearly identical average nDNA contents. Our results suggest the presence of aneuploidy among yeast cells of L. scottii.

KeyWords:
COENZYME-Q-SYSTEM, BASE COMPOSITION, GENERA RHODOSPORIDIUM, RHODOTORULA, CLASSIFICATION, CRYPTOCOCCUS, NUCLEAR DNA CONTENT

Addresses:
UNIV TOKYO, INST MOLEC & CELLULAR BIOSCI, 1-1-1 YAYOI, BUNKYO KU, TOKYO 113, JAPAN.
UNIV TOKYO, FAC SCI, DEPT BOT, BUNKYO KU, TOKYO 113, JAPAN.

Abstract:
The 18S ribosomal RNA gene sequences of the basidiomycetous yeasts Kondoa malvinella and Rhodosporidium dacryoidum, and an anamorphic yeast Sympodiomycopsis paphiopedili were determined. The 18S rRNA gene of R. dacryoidum IAM 13522 (ex type) revealed the presence of an intron-like region with a length of 404 nucleotides, which is presumably assigned to a group I intron. The phylogenetic tree, including 34 published reference sequences, was inferred from 1493 sites which could be unambiguously aligned. The molecular phylogeny, using the ascomycetes as an outgroup, divided the basidiomycetes into three major lineages. The first lineage was composed of the smut fungi (Ustilaginales), represented by Ustilago maydis, U. hordei, and Tilletia caries, including S. paphiopedili. The second lineage included the type species of teliospore-forming yeast genera Leucosporidium, Rhodosporidium, and Sporidiobolus, and the genera Erythrobasidium and Kondoa, both previously included in the Filobasidiaceae. Rhodosporidium dacryoidum showed a close relationship with E. hasegawianum, which was backed by a high bootstrap support. The rust fungi Cronartium ribicola and Peridermium harknessii were also included in this lineage. The last lineage was formed by the filobasidiaceous yeasts, Cystofilobasidium capitatum, Mrakia frigida, Filobasidium floriforme, and Filobasidiella neoformans, and the anamorphic yeasts Bullera alba (the anamorph of Bulleromyces albus) and Trichosporon cutaneum. Members of Tremella and selected hymenomycetous genera were also included in this lineage.

KeyWords:
18S rRNA gene sequence, basidiomycetous yeasts, phylogeny, yeast evolution

Addresses:
UNIV TOKYO, INST APPL MICROBIOL, YAYOI 1-1-1, BUNKYO KU, TOKYO 113, JAPAN.

Abstract:
Small subunit ribosomal RNA gene sequences were determined in nine species of the ballistoconidium-forming yeast genus Bensingtonia. The phylogenetic trees were constructed for the species of the genus Bensingtonia and related taxa containing Sporobolomyces and Bullera species by neighbor-joining, maximum parsimony and maximum likelihood methods. The phylogenetic trees showed that the basidiomycetous yeasts were divided into two main clusters, which were correlated well with the presence or absence of xylose in the cells. In the xylose-lacking basidiomycetous yeasts, seven species out of nine of the genus Bensingtonia constituted a distinct cluster. Bensingtonia ciliata, the type species of the genus, was included in this cluster. The remaining two species, B. intermedia and B. yamatoana, were located in the cluster which contained Rhodosporidium toruloides, Sporidiobolus johnsonii, Sporobolomyces roseus and Leucosporidium scottii. Erythrobasidium hasegawianum was distinctly located in the xylose-lacking basidiomycetous cluster. The molecular phylogeny showed clearly that the genus Bensingtonia was not monophyletic.

KeyWords:
COENZYME-Q-SYSTEM, YEAST-LIKE ORGANISMS, GROUP-I INTRONS, BASIDIOMYCETOUS YEASTS, BALLISTOSPOROUS YEASTS, GENERA RHODOSPORIDIUM, 18S rDNA SEQUENCES, RNA SEQUENCES

Addresses:
TAKASHIMA M, RIKEN, INST PHYS & CHEM RES, JAPAN COLLECT MICROORGANISMS, 2-1 HIROSAWA, WAKO, SAITAMA 35101, JAPAN.

Abstract:
The 18S ribosomal DNA (rDNA) sequences were determined for two anamorphic basidiomycetous yeasts, Rhodotorula lactosa and R. minuta. A phylogenetic tree was constructed by the neighbor-joining method using ascomycetous yeasts as an outgroup. The p-aminobenzoic acid (PABA) requiring species, R. lactosa, R. minuta, Erythrobasidium hasegawianum, and Rhodosporidium dacryoidum formed an independent lineage with 100% bootstrap confidence level in the basidiomycetous yeasts lacking xylose. In contrast, R. glutinis, the type species of Rhodotorula, showed a close relationship to Rhodosporidium toruloides and other non-PABA requiring basidiomycetous yeasts that lack xylose in the cell. The molecular phylogeny from this study showed the heterogeneity of the genus Rhodotorula, and suggested the taxonomic importance of PABA requirement in Rhodotorula and related taxa.

KeyWords:
RHODOSPORIDIUM, CLASSIFICATION, CRYPTOCOCCUS, 18S rDNA

Addresses:
INST PHYS & CHEM RES, JAPAN COLLECT MICROORGANISMS, WAKO, SAITAMA 35101, JAPAN.
JAPAN MARINE SCI & TECHNOL CTR, DEEP SEA MICROORGANISMS RES GRP, YOKOSUKA, KANAGAWA 237, JAPAN.

Abstract:
A region encoding the 16S rRNA was cloned by PCR from Streptomyces melanosporofaciens 7489 and sequenced by the chain-termination dideoxy sequencing method. A phylogenetic tree constructed by sequence alignment of 24 Streptomyces species suggests that there is little evolutionary distance between this strain and Streptomyces rimosus.

Keywords:
phylogenetic analysis, 16S rRNA gene, Streptomyces melanosporofaciens 7489

Addresses:
KYUNGPOOK NATL UNIV, COLL NAT SCI, DEPT MICROBIOL, TAEGU 702701, SOUTH KOREA.

Abstract:
Partial 18S ribosomal RNA nucleotide sequences were determined of all known species of ballistoconidium-forming yeasts. Complete 18S rDNA nucleotide sequences were determined in three Udeniomyces species and seven Bullera species. Phylogenetic analysis indicates that Bullera is polyphyletic, while Udeniomyces is monophyletic. The phylogenetic relationships of these yeasts correlate well with the biochemical composition of the cell wall, namely presence or absence of xylose, but not with the number of isoprenoids of the ubiquinone molecule.

Keywords:
ballistoconidium-forming yeasts, phylogeny, 18S rDNA

Addresses:
RIKEN, INST PHYS & CHEM RES, JAPAN COLLECT MICROORGANISMS, WAKO, SAITAMA 35101, JAPAN.

Abstract:
The sequence of the small subunit ribosomal coding gene (SSU rDNA) was determined for the type strains of seven species of the genus Bullera and two species which are now regarded as synonyms of species in the genera Bullera and Udeniomyces. The phylogenetic trees for these yeasts were constructed by neighbor-joining and maximum likelihood methods, including supposedly related yeasts and filamentous fungi whose SSU rDNA sequences were already known. Fifteen presently recognized species of Bullera were divided into two phylogenetic groups. Bullera mrakii, B. huiaensis, B. sinensis, B. oryzae, B. coprosmaensis, B. crocea, B. armeniaca, and B. variabilis constitute one cluster. In this cluster, the topologies of B. variabilis and orange-colored species, B. crocea and B. armeniaca, are different according to the neighbor-joining and maximum likelihood trees. Bullera pseudoalba, B. alba, B. unica, B. hannae, B. globispora, B. miyagiana, and B. dendrophila constitute another cluster. In this cluster, B. pseudoalba, B. alba, B. unica, and B. hannae constitute a branch but B. globispora, B. miyagiana, and B. dendrophila are located at positions far from one another although the former two species constitute a cluster in the maximum likelihood tree. Among the above species, B. dendrophila constitutes a cluster with Tsuchiyaea wingfieldii and Filobasidiella neoformans. The neotype strain of B. grandispora, which is now regarded a synonym of Udeniomyces piricola, is located close to the position of type strain U. piricola.

KeyWords:
BASIDIOMYCETOUS YEASTS, BALLISTOSPOROUS YEASTS, 18S rDNA SEQUENCES, BENSINGTONIA, UDENIOMYCES, TAXONOMY, XYLOSE

Addresses:
RIKEN, JAPAN COLLECT MICROORGANISMS, WAKO, SAITAMA 35101, JAPAN.
JAPAN MARINE SCI & TECHNOL CTR, DEEPSEA MICROORGANISMS RES GRP, YOKOSUKA, KANAGAWA 237, JAPAN.

Abstract:
Four group I introns were found in the nuclear small subunit ribosomal RNA genes (SSU rDNA) of the ballistoconidiogenous anamorphic yeast genus Bensingtonia. Two of them were found in B. ciliata, type species of the genus, with the length of 335 nt and 341 nt. The remaining two were found in B. yamatoana with lengths of 454 nt and 457 nt, respectively, The four introns were located at two different sites within the SSU rDNA. The first insertion site was the same position as group I introns found in the SSU rDNA of Dunaliella parva-5', Dunaliella salina, Protomyces inouyei-5' and Ustilago maydis, The second insertion site was shared among group I introns found in the SSU rDNA of Chlorella ellipsoidea, Hildenbrandia rubra, Pneumocystis carinii and Protomyces inouyei-3'. The putative secondary structures of the introns resembled those of subgroup IC1. Principal coordinate analysis of core regions of 15 group I introns found in SSU rDNA of eukaryotes showed that the sequence of B. ciliata-5' intron resembled that of the B. yamatoana-5' intron, and the sequence of the B. yamatoana-3' intron resembled that of the Protomyces inouyei-5' intron, Bensingtonia ciliata-3' intron had relatively different sequences compared to other group I introns examined. Group I introns in the nuclear SSU rDNA of red and green algae, ascomycetes and basidiomycetes, examined in this study, were scattered on the principal coordinate analysis.

KeyWords:
rDNA SEQUENCES, GROUP I INTRONS, FUNGUS

Addresses:
INST PHYS & CHEM RES, JAPAN COLLECT MICROORGANISMS, 2-1 HIROSAWA, WAKO, SAITAMA 35101, JAPAN.

Abstract:
A new species of ballistoconidium-forming yeast, Bensingtonia musae, was isolated from a dead leaf of Musa paradisiaca collected in the southeast seacoast of Bangkok, Thailand. B. musae showed physiological and biochemical characteristics similar to B. ingoldii and B. intermedia. DNA-DNA reassociation experiments, however, showed that it was distinct from these two species. B. musae is easily distinguished from B. ingoldii by the assimilation of sucrose, cellobiose, lactose, melezitose, soluble starch and nitrate, and from B. intermedia by the assimilation of cellobiose, L-arabinose, erythritol and salicin, and the requirement of p-aminobenzoic acid and pyridoxine. In the phylogenetic tree constructed based on small subunit rRNA gene sequences, B. musae was located at a cluster which was composed of B. ciliata, the type species of the genus, B. ingoldii, B. miscanthi, B. naganoensis, B. phylladus, B. subrosea and B. yuccicola. Among these species, B. musae was the most closely related to B. ingoldii.

KeyWords:
SPOROBOLOMYCES-PHYLLADUS, MISCANTHUS-SINENSIS, LEAVES, SYSTEM

Addresses:
RIKEN, INST PHYS & CHEM RES, JAPAN COLLECT MICROORGANISMS, 2-1 HIROSAWA, WAKO, SAITAMA 35101, JAPAN.

Abstract:
The 18S ribosomal RNA gene (rDNA) sequences of eight species of basidiomycetous yeasts were determined. As the result of molecular phylogenetic analysis from these sequences with other known data, the basidiomycetous yeasts which reproduce by the stalked conidium, Fellomyces polyborus, Kockovaella thailandica, Kurtzmanomyces nectairei, Sporobolomyces xanthus, Sterigmatomyces halophilus, Sterigmatosporidium polymorphum, and Tsuchiyaea wingfieldii, were separated to two phylogenetic groups which were correlated well with the presence or absence of xylose in the cells. The xylose-lacking species, Kurtzmanomyces nectairei, Sporobolomyces xanthus, and Sterigmatomyces halophilus, were located at closely related positions in the tree, and showed a close relationship with some Bensingtonia species. On the other hand, the xylose-containing species, Fellomyces polyborus, Kockovaella thailandica, Sterigmatosporidium polymorphum, and Tsuchiyaea wingfieldii made a branch with the species of Bullera and Tremella. Fibulobasidium inconspicuum, a species of Sirobasidiaceae (Tremellales), was also included in this branch. The molecular phylogeny deduced from 18S rDNA showed that the ability to produce stalked conidia is not a rational phylogenetic criterion, and supported the taxonomic importance of cellular xylose in basidiomycetous yeasts.

KeyWords:
basidiomycetous yeasts, stalked conidia, 18S rDNA,  molecular phylogeny

Addresses:
JAPAN MARINE SCI & TECHNOL CTR, DEEPSEA MICROORGANISMS RES GRP, YOKOSUKA, KANAGAWA 237, JAPAN.

Abstract:
Four strains of anamorphic yeasts isolated from fruit bodies of mushrooms collected in Japan were found to represent three new species of the genus Candida. These species resemble Candida mesenterica in characteristics commonly employed in the classification of yeast. On the basis of DNA-DNA reassociation, however, they were clearly distinguished from C. mesenterica and from one another. Three new species Candida fungicola, Candida sagamina, and Candida fukazawae, are proposed for these yeasts. The analysis of SSU rDNA sequences suggested that these three species were closely related to each other and to C. mesenterica and C. suecica.

KeyWords:
Candida fungicola, Candida sagamina, Candida fukazawae, NEW YEAST SPECIES, SSU RDNA SEQUENCE

Addresses:
RIKEN, INST PHYS & CHEM RES, JAPAN COLLECT MICROORGANISMS, 2-1 HIROSAWA, WAKO, SAITAMA 35101, JAPAN.
DEPT APPL BIOL & CHEM TOKYO UNIV AGRICUL, 1-1-1 SAKURAOKA, SETAGAYA-KU, TOKYO 156-8502. JAPAN

Abstract:
Phylogenetic relationships of 33 Candida species containing galactose in the cells were investigated by using 18S ribosomal DNA sequence analysis. Galactose-containing Candida species and galactose-containing species from nine ascomycetous genera were a heterogeneous assemblage. They were divided into three clusters (II, III, and IV) which were phylogenetically distant from cluster I, comprising 9 galactose-lacking Candida species, C. glabrata, C. holmii, C. krusei, C. tropicalis (the type species of Candida), C. albicans, C. viswanathii, C. maltosa, C. parapsilosis, C. guilliermondii, and C. lusitaniae, and 17 related ascomycetous yeasts. These three clusters were also phylogenetically distant from Schizosaccharomyces pombe, which contains galactomannan in its cell wall. Cluster II comprised C. magnoliae, C. vaccinii, C. apis, C. gropengiesseri, C. etchellsii, C. floricola, C. lactiscondensi, Wickerhamiella domercqiae, C. versatilis, C. azyma, C. vanderwaltii, C. pararugosa, C. sorbophila, C. spandovensis, C. galacta, C. ingens, C. incommunis, Yarrowia lipolytica, Galactomyces geotrichum, and Dipodascus albidus. Cluster III comprised C. tepae, C, antillancae and its synonym C. bondarzewiae, C. ancudensis, C. petrohuensis, C. santjacobensis, C. ciferrii (anamorph of Stephanoascus ciferrii), Arxula terrestris, C. castrensis, C. valdiviana, C, paludigena, C. blankii, C. salmanticensis, C. auringiensis, C. bertae, and its synonym C. bertae var. chiloensis, C. edax (anamorph of Stephanoascus smithiae), Arxula adeninivorans, and C. steatolytica (synonym of Zygoascus hellenicus). Cluster IV comprised C. cantarellii, C. vinaria, Dipodascopsis uninucleata, and Lipomyces lipofer. Two galactose-lacking and Q-8-forming species, C. stellata and Pichia pastoris, and 5 galactose-lacking and Q-9-forming species, C. apicola, C. bombi, C. bombicola, C. geochares, and C. insectalens, were included in Cluster II. Two galactose-lacking and Q-9-forming species, C. drimydis and C. chiropterorum, were included in Cluster III.

Keywords:
galactose-containing Candida species, molecular phylogeny, 18S ribosomal DNA sequences

Addresses:
Suzuki M, RIKEN, Inst Phys & Chem Res, Japan Collect Microorganisms, Wako, Saitama 3510198, Japan.
RIKEN, Inst Phys & Chem Res, Japan Collect Microorganisms, Wako, Saitama 3510198, Japan.