Identification of CARE‐2‐negative Candida albicans isolates as Candida dubliniensis

Morschhäuser, Joachim; Ruhnke, Markus; Michel, Sonja; Hacker, Jörg

doi:10.1046/j.1439-0507.1999.00259.x

Cited by 36 publications

(10 citation statements)

References 12 publications

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“…Analysis of the subtelomeric regions of other strains and related Candida species may reveal the significance of such structures. Of interest, a recent report (Morschhauser et al 1999) reveals that Candida dubliniensis, a very close relative of C. albicans, lacks sequences hybridizing to CARE-2, suggesting that the subtelomeric regions of these two species have diverged rapidly.…”

Section: Discussionmentioning

confidence: 99%

Multiple LTR-Retrotransposon Families in the Asexual Yeast Candida albicans

Goodwin

Poulter²

2000

Genome Res.

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We have begun a characterization of the long terminal repeat (LTR) retrotransposons in the asexual yeast Candida albicans. A database of assembled C. albicans genomic sequence at Stanford University, which represents 14.9 Mb of the 16-Mb haploid genome, was screened and >350 distinct retrotransposon insertions were identified. The majority of these insertions represent previously unrecognized retrotransposons. The various elements were classified into 34 distinct families, each family being similar, in terms of the range of sequences that it represents, to a typical Ty element family of the related yeast Saccharomyces cerevisiae. These C. albicans retrotransposon families are generally of low copy number and vary widely in coding capacity. For only three families, was a full-length and apparently intact retrotransposon identified. For many families, only solo LTRs and LTR fragments remain. Several families of highly degenerate elements appear to be still capable of transposition, presumably via trans-activation. The overall structure of the retrotransposon population in C. albicans differs considerably from that of S. cerevisiae. In that species, retrotransposon insertions can be assigned to just five families. Most of these families still retain functional examples, and they generally appear at higher copy numbers than the C. albicans families. The possibility that these differences between the two species are attributable to the nonstandard genetic code of C. albicans or the asexual nature of its genome is discussed. A region rich in retrotransposon fragments, that lies adjacent to many of the CARE-2/Rel-2 sub-telomeric repeats, and which appears to have arisen through multiple rounds of duplication and recombination, is also described.

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Section: Discussionmentioning

confidence: 99%

Multiple LTR-Retrotransposon Families in the Asexual Yeast Candida albicans

Goodwin

Poulter²

2000

Genome Res.

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“…Candida dubliniensis strains CD36 (Sullivan et al ., 1995), Wü284 (Morschhaüser et al ., 1999) and CdUM4B ( ura3 / ura3 : (Staib et al ., 2001)) and C. albicans SC5314 (Gillum et al ., 1984) were used in this study. Strains were routinely grown at 30°C in YPD containing 0.02% adenine and 0.008% uridine or in SD minimal medium (Sherman, 1991).…”

Section: Methodsmentioning

confidence: 99%

Genome‐wide gene expression profiling and a forward genetic screen show that differential expression of the sodium ion transporter Ena21 contributes to the differential tolerance of Candida albicans and Candida dubliniensis to osmotic stress

Enjalbert

Moran

Vaughan

et al. 2009

Molecular Microbiology

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SummaryCandida albicans is more pathogenic than Candida dubliniensis. However, this disparity in virulence is surprising given the high level of sequence conservation and the wide range of phenotypic traits shared by these two species. Increased sensitivity to environmental stresses has been suggested to be a possible contributory factor to the lower virulence of C. dubliniensis. In this study, we investigated, in the first comparison of C. albicans and C. dubliniensis by transcriptional profiling, global gene expression in each species when grown under conditions in which the two species exhibit differential stress tolerance. The profiles revealed similar core responses to stresses in both species, but differences in the amplitude of the general transcriptional responses to thermal, salt and oxidative stress. Differences in the regulation of specific stress genes were observed between the two species. In particular, ENA21, encoding a sodium ion transporter, was strongly induced in C. albicans but not in C. dubliniensis. In addition, ENA21 was identified in a forward genetic screen for C. albicans genomic sequences that increase salt tolerance in C. dubliniensis. Introduction of a single copy of CaENA21 was subsequently shown to be sufficient to confer salt tolerance upon C. dubliniensis.

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“…To facilitate the genetic manipulation of C. dubliniensis we constructed a ura3 mutant of the previously characterized strain Wü284 (19,25,26) by targeted gene disruption using the MPA R -flipping strategy (31). Two different deletion constructs were made for inactivation of the two URA3 alleles.…”

Section: Resultsmentioning

confidence: 99%

Isogenic Strain Construction and Gene Targeting in Candida dubliniensis

et al. 2001

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Candida dubliniensis is a recently described opportunistic fungal pathogen that is closely related to Candida albicans but differs from it with respect to epidemiology, certain virulence characteristics, and the ability to develop fluconazole resistance in vitro. A comparison of C. albicans and C. dubliniensis at the molecular level should therefore provide clues about the mechanisms used by these two species to adapt to their human host. In contrast to C. albicans, no auxotrophic C. dubliniensis strains are available for genetic manipulations. Therefore, we constructed homozygous ura3 mutants from a C. dubliniensis wild-type isolate by targeted gene deletion. The two URA3 alleles were sequentially inactivated using the MPA R -flipping strategy, which is based on the selection of integrative transformants carrying a mycophenolic acid resistance marker that is subsequently deleted again by site-specific, FLP-mediated recombination. The URA3 gene from C. albicans (CaURA3) was then used as a selection marker for targeted integration of a fusion between the C. dubliniensis MDR1 (CdMDR1) promoter and a C. albicans-adapted GFP reporter gene. Uridine-prototrophic transformants were obtained with high frequency, and all transformants of two independent ura3-negative parent strains had correctly integrated the reporter gene fusion into the CdMDR1 locus, demonstrating that the CaURA3 gene can be used for efficient and specific targeting of recombinant DNA into the C. dubliniensis genome. Transformants carrying the reporter gene fusion did not exhibit detectable fluorescence during growth in yeast extractpeptone-dextrose medium in vitro, suggesting that CdMDR1 is not significantly expressed under these conditions. Fluconazole had no effect on MDR1 expression, but the addition of the drug benomyl strongly activated the reporter gene fusion in a dose-dependent fashion, demonstrating that the CdMDR1 gene, which encodes an efflux pump mediating resistance to toxic compounds, is induced by the presence of certain drugs.Several yeast species within the genus Candida are opportunistic pathogens of humans, Candida albicans being by far the most frequently isolated and also the most pathogenic species (20). Recently, a previously unrecognized Candida species, Candida dubliniensis, has been described (28). C. dubliniensis is closely related to C. albicans, and before the phylogenetic separation of the two species was recognized and reliable phenotypic and molecular markers to distinguish them became established, C. dubliniensis was often misidentified as C. albicans (27). Whereas C. albicans is a member of the normal microflora in most healthy persons, C. dubliniensis has been isolated primarily from the oral cavities of human immunodeficiency virus (HIV)-infected individuals and AIDS patients. However, recent epidemiological studies have also identified C. dubliniensis in cases of oral infection in non-HIV-infected individuals and in cases of septicemia, although at a lower incidence than C. albicans (3,13,21,23,29). These observat...

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Identification of CARE‐2‐negative Candida albicans isolates as Candida dubliniensis

Cited by 36 publications

References 12 publications

Multiple LTR-Retrotransposon Families in the Asexual Yeast Candida albicans

Multiple LTR-Retrotransposon Families in the Asexual Yeast Candida albicans

Genome‐wide gene expression profiling and a forward genetic screen show that differential expression of the sodium ion transporter Ena21 contributes to the differential tolerance of Candida albicans and Candida dubliniensis to osmotic stress

Isogenic Strain Construction and Gene Targeting in Candida dubliniensis

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