Submitted to: Book Chapter
Publication Type: Book / chapter
Publication Acceptance Date: 3/1/2003
Publication Date: 5/1/2003
Citation: KURTZMAN, C.P., FELL, J.W., ROBERT, V., BOEKHOUT, T. METHODS TO IDENTIFY YEAST. BOOK CHAPTER. BOEKHOUT, T., ROBERT, V. EDITORS. B. BEHR'S VERLAG GMBH& CO. HAMBURG, GERMANY. YEASTS IN FOOD. 2003. P. 69-121. Interpretive Summary:
Technical Abstract: Yeasts are commonly identified from either phenotype or, more recently, from diagnostic gene sequences. Methods based on phenotype include fermentation reactions on a select set of sugars and growth responses on various carbon and nitrogen sources or on other diagnostic compounds. Isolates are further characterized phenotypically from the microscopic appearance of vegetative cells as well as sexual states because this information often gives clues to the identity of a strain. Molecular methods for yeast identification include nuclear DNA reassociation as well as the more recent and faster procedure of sequencing species-specific genes or the use of oligonucleotide sequences that react to a species-specific region of genomic DNA. These so-called "molecular probes" may have a marker molecule attached or they may be used in pairs, that when employed in a PCR reaction, amplify a species-specific region of DNA. The DNA-based identifications are far more reliable than those from phenotypic tests, and much faster. Nonetheless, in the absence of facilities for molecular comparisons, satisfactory identifications can often be made from phenotype. For this reason, both phenotype-based methods, as well as molecular techniques are given in this chapter.