Chromosomal variations in Candida albicans

Abstract

We report here the separation of chromosomal DNA molecules from the diploid pathogenic yeast C. albicans by field inversion gel electrophoresis (FIGE)(1). Our earlier work on C. albicans ATCC strain 10261 revealed a pulsed field gel electrophoretic pattern of six bands, two of which were possibly doublets (2). In the present study we found that FIGE gave superior resolution with uniform DNA mobility between lanes, and therefore could be used to examine the possibility of electrophoretic karyotype variation in this asexual yeast. The extension of our study to other strains of C. albicans showed that local clinical isolates, strain 22114 (fromM.D.Richardson, Birmingham, England) and our ATCC 10261 reference strain exhibit considerable differences in their FIGE banding patterns (Figure). However, certain similarities are apparent, especially in bands 5 and 6. Probing Southern blots with C. albicans DNA probes which complement the HIS3, ADE2 and URA3 genes in S. cerevisiae gave results supporting this conclusion. Close examination of the variant chromosomes, including further probing, suggested that they may have had common origins, but have undergone reanrangements which involve either one or both homologues of a diploid pair. However, we do not believe that C. albicans chromosomes are overly unstable, since ATCC 10261 strains freeze-dried in 1960 and 1965 gave the same banding pattern as an ATCC 10261 strain in laboratory culture for the last 15 years.

Assignment of cloned genes to the seven electrophoretically separated Candida albicans chromosomes.

“…Using the first technique, we have recently presented evidence for nine separable bands in C. albicans, although in no one strain were all nine resolvable (14). Similar results were obtained by Snell et al (24,25). Since blotting of these electrophoretic karyotypes is possible (2), one can assign cloned genes to particular bands and thus, in principle, identify the electrophoretic band corresponding to a genetically determined linkage group.…”

Estimation of chromosome number and size by pulsed-field gel electrophoresis (PFGE) in medically important Candida species

“…Kuryotypes of the Candida species Karyotypes have been analysed in C. albicans (Merz et al, 1988;Lott etal., 1987;Mahrousetal., 1990;Lasker ef al., 1989;Snell et al, 1987;Magee et al, 1988;Iwaguchi et al, 1990) (Sor & Fukuhara, 1989) and C. glabrata (Kaufmann & Merz, 1989;Asakura et al, 1991). Only C. albicans has been studied extensively.…”

Candida albicans strain delineation

“…Pulsed-field electrophoresis has permitted the separation of chromosome-sized DNA molecules of many organisms including the medically important yeasts C. albicans (42,47,52,53,63,100,101), C. stellatoidea (41,53), C. tropicalis (47,53), C. guilliermondii (53), C. glabrata (34,47,53), C. utilis (18), C. shehatae (18), Cryptococcus neoformans (81), and S. cerevisiae (18,47,53,63,101) and strains of 14 other ascomycetous and basidiomycetous yeast genera (18). The striking finding has been the extent of variation in the electrophoretic karyotypes observed among C. albicans isolates.…”

“…Magee and Magee (53) in 1987 showed that four strains had five to seven DNA bands and each strain had different electrophoretic karyotype patterns. Snell et al (100) showed that six of six strains of C. albicans studied had discernible karyotypic variation with five to seven discrete bands. Merz et al (63) showed that both the number of chromosome-sized DNA bands (seven to nine) and the patterns of the bands varied significantly.…”