Classification of some dermatophytes by pyrolysis–gas–liquid chromatography

Abstract

Samples from dried colonies of 21 strains of Nannizzia and Arthroderma were analyzed by pyrolysis–gas–liquid chromatography. Characteristic peak patterns produced by all the strains were used as markers to correct random drift in retention time so that corresponding peaks in different pyrograms could be homologized. Variation in sample size was compensated for by comparing peaks on each pyrogram with a particular major component and scoring them simply as 0 (absent), 1 (small), or 2 (large). Proximities were calculated and analyzed for clusters by the TAXMAP procedure. The analysis always grouped replicate samples together in the same cluster. Opposite mating types of the same species were sometimes placed in the same cluster and sometimes in separate clusters. The (+) mating type of Arthroderma benhamiae was placed in a cluster with both mating types of Nannizzia gypsea and N. obtusa, while the (−) mating type replicates of A. benhamiae were placed in a cluster by themselves. Finding a greater difference between pyrograms of different mating types of one species than between pyrograms of different species was unexpected and requires further investigation.