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Specific identification of Candida albicans by hybridization with oligonucleotides derived from ribosomal DNA internal spacers
Author(s) -
Botelho Ana R.,
Planta Rudi J.
Publication year - 1994
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/yea.320100603
Subject(s) - biology , candida albicans , internal transcribed spacer , oligonucleotide , ribosomal dna , corpus albicans , ribosomal rna , southern blot , dna–dna hybridization , genomic dna , yeast , nucleic acid thermodynamics , dna , genetics , hybridization probe , microbiology and biotechnology , oligomer restriction , dna sequencing , gene , phylogenetics , base sequence
In order to develop DNA probes for rapid, sensitive and specific detection of the pathogenic yeast species Candida albicans , we carried out comparative sequence analysis of the two internal transcribed spacer regions (ITS1 and ITS2) of the ribosomal DNA (rDNA) units of C. albicans and the closely related pathogenic species C. tropicalis . While overall sequence similarity between the two species was considerable (65–75%), both ITS1 and ITS2 were found to contain distinct regions with sufficient sequence divergence to make them suitable as specific target sites for the identification of C. albicans . On the basis of these results one ITS1‐derived ( ANAB1 ) and two ITS2‐derived ( ANAB2 and ANAB3 ) oligonucleotides were selected, chemically synthesized, and used as hybridization probes. Their specificity and reliability were evaluated in dot‐blot hybridization experiments with total genomic DNA from 13 strains of medically important Candida species, six strains of other yeast genera associated with man and animals, and ten strains previously identified as C. albicans by phenotypic criteria. Under well‐defined hybridization conditions the three probes hybridized exclusively with DNA derived from strains belonging to the species C. albicans , thus demonstrating their potential clinical usefulness. The failure of four of the (presumed) C. albicans strains to show hybridization to the ITS probes sheds doubt upon their taxonomic classification, which is reinforced by other phenotypic aspects of these strains.