Off-campus South Dakota State University users: To download campus access theses, please use the following link to log into our proxy server with your South Dakota State University ID and password.

Non-South Dakota State University users: Please talk to your librarian about requesting this thesis through interlibrary loan.


Guorong Xu

Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)

Department / School


First Advisor

Thomas P. West


Yeast is the common name given to fungi that are primarily unicellular. Yeast are simple eukaryotic organisms which are commonly used in biochemistry, cellular biology and molecular biology to provide information concerning biochemical and genetic processes. Cellular and subcellular structures, metabolic pathways, protein synthesis, DNA and RNA syntheses, and gene expression have been examined in yeast species. Perhaps the most widely used species of yeast are Saccharomyces cerevisiae. This species reproduces by budding or fission sexual reproduction occurs vegetatively in S.­ cerevisiae when two haploid cells of opposite mating types fuse to form a diploid zygote. The diploid vegetative cells may either continue the vegetative cycle by budding or under special conditions undergo meiosis to produce four haploid ascospores. These ascospores can undergo germination to form haploid cells. Of the developmental processes known in yeast, germination of yeast ascospores is probably the least understood. Germination and outgrowth of yeast spores provide an excellent biological system to study biochemical events during eukaryotic development. The developmental sequence involved in the transition of a S. cerevisiae ascospore to a vegetative cell has been studied but is not fully understood (1-4). The heterothallic strain AP-3 of S. cerevisiae is utilized in this investigation of yeast germination. Prior work has largely focused upon S. cerevisiae homothallic strains. In the present study, ascospore germination was analyzed from both a nutritional as well as a biochemical perspective.

Library of Congress Subject Headings

Saccharomyces cerevisiae



Number of Pages



South Dakota State University