Taxonomic
investigation of Saccharomyces boulardii.
Laura C Edwards,
Lubomira Stateva
Biomolecular Sciences, UMIST, PO Box 88, Manchester, M60 1QD, UK
(L.Edwards@postgrad.umist.ac.uk)
S. boulardii, classified as a
separate species due to its probiotic nature, is successfully used in the
probiotic treatment of diarrhoea, particularly the chronic or recurrent forms.
However, there has always been controversy regarding its taxonomic
classification. Previously McCullough et al., (1998) applied
RFLP-typing of PCR-amplified products from the rDNA intergenic transcribed
spacer regions (including the 5.8S rDNA) and found that commercially available
strains of S. boulardii from France and Italy were indistinguishable from those of S.
cerevisiae.
In the current investigation we are applying a wider range of diagnostic
methods to unambiguously determine if S. boulardii (currently patented as a
separate species) is different from S. cerevisiae. Our investigation will
report the results of: i) DNA sequencing of specific genes (SRB1/PSA1, PKC1,
CHS1, CHS3,
the mitochondrial genes COX2 and COX3), and randomly chosen intergenic regions;
ii) CHEF karyotyping and hybridisation with unique S. cerevisiae probes designed for the
centromeric and end regions of each chromosome; iii) Ty fingerprinting; iv)
microarray hybridisation genome comparison. These experiments will confirm the
relationship between S. boulardii and S. cerevisiae. McCullough MJ, Clemons
KV, McCusker JH, Stevens DA (1998) J. Clin. Micro. 36:2613-2617