Phylogenetic and Taxonomic Heterogeneity of Cryptococcus humicolus by Analysis of the Sequences of the Internal Transcribed Spacer Regions and 18S rDNA, and the Phylogenetic Relationships of C. humicolus, C. curvatus, and the Genus Trichosporon

Sugita, Takashi; Takashima, Masako; Ikeda, Reiko; Nakase, Takashi; Saitô, Takako

doi:10.1111/j.1348-0421.2000.tb02520.x

Cited by 25 publications

(28 citation statements)

References 26 publications

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“…ITS2 and ITS1 were better than 26S at resolving the taxonomic position of Cryptococcus humicolus. In agreement with our data, this species has been previously shown to belong to the Trichosporon clade by analysis of 18S rDNA and ITS sequences (29), as well as 26S rDNA (10). In the ascomycetous group, Pichia species were polyphyletic in all three dendrograms.…”

Section: Discussionsupporting

confidence: 80%

“…DNA-based methods have been used successfully to characterize pathogenic yeasts and provide evidence of novel species (1,2,5,7,10,12,14,25,(27)(28)(29)31). We have established an ITS database that provides accurate identification of at least 40 species of medically important yeasts.…”

Section: Discussionmentioning

confidence: 99%

“…Invasive procedures or immunosuppression increases the risk of fungemia (24,34), and drug-resistant strains have emerged (9,21). Although Candida albicans is still the predominate agent of nosocomial infection, serious infections caused by other yeasts have increased in frequency (8,11,29,34). For example, species of Cryptococcus other than Cryptococcus neoformans, previously considered to be nonpathogenic saprophytes, have been reported to cause cryptococcosis (28).…”

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confidence: 99%

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Polymorphic Internal Transcribed Spacer Region 1 DNA Sequences Identify Medically Important Yeasts

Chen¹,

Eisner²,

Kattar³

et al. 2001

J Clin Microbiol

205

141

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Species-specific polymorphisms in the noncoding internal transcribed spacer 2 (ITS2) region of the rRNA operon provide accurate identification of clinically significant yeasts. In this study, we tested the hypothesis that ITS1 noncoding regions contain diagnostically useful alleles. The length of ITS1 region PCR products amplified from 40 species (106 clinical strains, 5 reference strains, and 30 type strains) was rapidly determined with single-base precision by automated capillary electrophoresis. Polymorphisms in the PCR product length permitted 19 species to be distinguished by ITS1 alone, compared with 16 species distinguished by using only ITS2. However, combination of both ITS alleles permitted identification of 30 species (98% of clinical isolates). The remaining 10 species with PCR products of similar sizes contained unique ITS alleles distinguishable by restriction enzyme analysis. DNA sequence analysis of amplified ITS1 region DNA from 79 isolates revealed species-specific ITS1 alleles for each of the 40 pathogenic species examined. This provided identification of unusual clinical isolates, and 53 diagnostic ITS1 sequences were deposited in GenBank. Phylogenetic analyses based on ITS sequences showed a similar overall topology to 26S rRNA gene-based trees. However, different species with identical 26S sequences contained distinct ITS alleles that provided species identification with strong statistical support. Together, these data indicate that the analysis of ITS polymorphisms can reliably identify 40 species of clinically significant yeasts and that the capacity for identifying potentially new pathogenic species by using this database holds significant promise.The complexity of opportunistic fungal infections is increasing as more patients are adversely affected by an expanding diversity of yeasts. Invasive procedures or immunosuppression increases the risk of fungemia (24, 34), and drug-resistant strains have emerged (9, 21). Although Candida albicans is still the predominate agent of nosocomial infection, serious infections caused by other yeasts have increased in frequency (8,11,29,34). For example, species of Cryptococcus other than Cryptococcus neoformans, previously considered to be nonpathogenic saprophytes, have been reported to cause cryptococcosis (28). Adequate treatment of these infections depends on early detection and accurate identification of the pathogens. However, conventional identification by evaluation of morphological and physiological characteristics can be laborious, sometimes leads to incorrect classification and identification (2, 3, 13), and can be impeded by database limitations (4, 6).To develop a rapid molecular method for identifying yeasts, we recently analyzed the length and sequence polymorphisms in the DNA of noncoding internal transcribed spacer region 2 (ITS2) of the rRNA operon (2). ITS2 region polymorphisms permitted accurate identification of over 400 clinical strains representing 34 species of pathogenic yeasts. ITS2 region PCR product length determined by aut...

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Section: Discussionsupporting

confidence: 80%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Polymorphic Internal Transcribed Spacer Region 1 DNA Sequences Identify Medically Important Yeasts

Chen¹,

Eisner²,

Kattar³

et al. 2001

J Clin Microbiol

205

141

View full text Add to dashboard Cite

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“…These species, with the exception of C. curvata, are taxonomically highly heterogeneous. We have previously reported the intraspecies diversity of C. humicola and C. laurentii by sequence analyses of the 18S,28S, and internal transcribed spacer (ITS) regions of the rRNA gene (20,21). Recently, Fonseca et al (3) demonstrated the species heterogeneity of C. albidus by using 28S rONA and ITS region sequences.…”

mentioning

confidence: 99%

Intraspecies Diversity of Cryptococcus albidus Isolated from Humans as Revealed by Sequences of the Internal Transcribed Spacer Regions

Sugita

Takashima

Ikeda

et al. 2001

Microbiology and Immunology

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The basidiomycetous yeast, Cryptococcus albidus, shows intraspecies diversity, but it is rarely isolated from immunocompromised patients. Nineteen strains of C. albidus, including nine clinical isolates, were re-c1assified by sequences of their rRNA internal transcribed spacer (ITS) regions. The nine clinical isolates were genetically diverse and included both C. albidus and C. dijJluens. One clinical isolate, recovered from the blood of an AIDS patient, represented a new species. Only small differences were found in the biochemical and serological characteristics of C. albidus and C. dijJluens. All isolates were sensitive to amphotericin B, but several isolates were resistant to fluconazole and itraconazole. C. albidus heterogeneity should be taken into consideration when identifying clinical isolates.

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“…For further taxonomical analysis of strain TYC-19, the ITS sequences, which appears to be a powerful technique to differentiate between phylogenetically intimately related species 18) , were determined. These results revealed that the strains were divided into three groups and strain TYC-19 branched off independently from all strains (…”

Section: Resultsmentioning

confidence: 99%

Conversion of Beet Molasses and Cheese Whey into Fatty Acid Methyl Esters by the Yeast Cryptococcus curvatus

Takakuwa

Saito

2010

J. Oleo Sci.

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Eighty-one yeast isolates from raw milk were surveyed for the production of fatty acid methyl esters (FAME). Only one species, identified as Cryptococcus curvatus, produced FAME at a detectable level. Cr. curvatus TYC-19 produced more FAME from beet molasses and cheese whey medium than other strains of the same species. In both media, the major FAME produced were linoleic and oleic acid methyl esters. Sequence analysis of the internal transcribed spacer region of ribosomal DNA indicated that TYC-19 diverged from the same species.

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Phylogenetic and Taxonomic Heterogeneity of Cryptococcus humicolus by Analysis of the Sequences of the Internal Transcribed Spacer Regions and 18S rDNA, and the Phylogenetic Relationships of C. humicolus, C. curvatus, and the Genus Trichosporon

Cited by 25 publications

References 26 publications

Polymorphic Internal Transcribed Spacer Region 1 DNA Sequences Identify Medically Important Yeasts

Polymorphic Internal Transcribed Spacer Region 1 DNA Sequences Identify Medically Important Yeasts

Intraspecies Diversity of Cryptococcus albidus Isolated from Humans as Revealed by Sequences of the Internal Transcribed Spacer Regions

Conversion of Beet Molasses and Cheese Whey into Fatty Acid Methyl Esters by the Yeast Cryptococcus curvatus

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