Molecular probe for identification of medically important Candida species and Torulopsis glabrata

Abstract

A cloned DNA fragment from Candida albicans containing the gene for the protein actin was used to probe the molecular structure of the actin gene of several medically important yeasts (C. albicans, Candida stellatoidea, Candida tropicalis, Candida pseudotropicalis, Candida krusei, Candida parapsilosis, Candida guilliermondii, and Torulopsis glabrata). Whole-cell DNA from each species was digested with restriction endonucleases, electrophoresed on agarose gels, and transferred to nitrocellulose. Radioactively labeled C. albicans actin gene was hybridized to the DNA fragments on the nitrocellulose. The C. albicans probe produced a strong signal with all of the Candida DNAs tested, indicating considerable conservation of this gene. In addition, the actin genes of all of the species tested were found to have no internal EcoRI or SalI restriction sites. With the exception of C. guilliermondii, all of the species tested had a single internal HindIII recognition site. However, the location of flanking restriction sites was found to be species specific. For all of the enzymes tested, the locations of the flanking restriction sites in C. albicans and C. stellatoidea were identical; all of the other strains yielded fragments clearly distinct from one another. These differences provide a molecular tool for the differentiation of medically important Candida species.