Classification of ascoideaceous yeasts based on the electrophoretic comparison of enzymes and coenzymes Q systems.

Abstract

Sixty one strains of ascoideaceous yeasts belonging to twenty species of nine genera were examined from a taxonomical viewpoint based on a study of the electrophoretic comparison of the enzymes and the coenzymes Q (Co-Q) systems. The fifty strains, excluding those yeasts in which the detected number of enzymes was 3 or less, were divided into 4 clusters and 2 subclusters by numerical analysis of the relative electrophoretic mobilities (Rm) of 8 enzymes. On the other hand, the Co-Q systems of the ascoideaceous yeasts were Q-7, Q-8, or Q-9. These Co-Q systems and the septal ultrastructures coincided with each other. It is possible to divide these yeasts into four groups on the basis of similarity value according to the Rm of 8 enzymes: Saccharomycopsis lipolytica, other Saccharomycopsis spp. and related genera, Hyphopichia burtonii and/or Stephanoascus ciferrii, and Ambrosiozyma and Hormoascus. Saccharomycopsis lipolytica should be excluded from the genus Saccharomycopsis and is assigned to the genus Yarrowia. Ambrosiozyma and Hormoascus are considered to be cogeneric. Our data revealed close taxonomic relationship in the numerical classification based on the Rm of enzymes, Co-Q systems, and the septal ultrastructure.