A molecular analysis of the relatedness of anamorphic yeasts currently classified as Candida pintolopesii

Author

Richard Ashley Hurt

Date of Award

12-1997

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Microbiology

Major Professor

Stuart Riggsby

Committee Members

David Brian, Jeffrey M. Becker

Abstract

A system of comparative nucleic acid methods appropriate to a number of levels of sensitivity or discrimination were used to address the validity of the current conspecific assignment of the yeasts classified as Candida pintolopesii<\em>. Based on preliminary molecular data it was hypothesized that yeasts classified a C. pintolopesii<\em> would not exhibit a level of molecular divergence that is consistent with yeasts classified as conspecific. The relatedness among the C. pintolopesii<\em> strains and the alleged perfect form Arxiozyma telluris<\em> was investigated using aqueous phase DNA-DNA hybridization of single copy genomic DNA, karyotypes determined by clamped homogeneous electrical field electrophoresis, RFLP analyses, and comparison of ribosomal RNA gene sequences. The systematic level at which the alleged C. pintolopesii<\em> strains are related was estimated by a comparison of the results obtained for each of the nucleic acid methods used in this study to standards established from other well characterized yeast species and genera. The results of the molecular analyses demonstrated that the yeasts classified as C. pintolopesii<\em>, and the assigned teleomorph A. telluris<\em>, are related as a sibling species complex. The approach and the species concept presented herein can serve as a model for the examination of relationships among the members of entire genus Candida, and for the yeasts in general.