ANALYTICAL ISOELECTRIC-FOCUSING OF SECRETED DERMATOPHYTE PROTEINS APPLIED TO TAXONOMIC DIFFERENTIATION OF MICROSPORUM AND TRICHOPHYTON SPECIES (PRELIMINARY STUDIES)

  • 1 January 1984
    • journal article
    • research article
    • Vol. 22  (5) , 369-379
Abstract
Culture filtrates were prepared from dermatophytes under standard conditions and adapted for analytical isoelectric focusing in thin layer polyacrylamide gels over the pH range 3.5-9.5. Dermatophytes grown in trypticase soy broth secreted a large number of proteins displaying a wide range of isoelectric points (pI). T. megninii extracts contained a triplet of proteins focusing in the pH 8.0-8.5 range that were absent in taxonomically related T. kuryangei isolates. Single ascospore isolates and standard tester strains of Nannizzia otae (+) mating type were differentiated from the (-) mating type by proteins focusing at pH 6.5 and 8.4. These were markedly reduced in the (+) type. The isofocused pattern of M. canis conformed closely to the (-) mating type of N. otae. The protein patterns of T. megninii and T. kuryangei were distinct from those obtained with M. canis and M. equinum because of an intense-staininig broad protein band, pI 7.2, and 3 periodic acid-Schiff-positive glycoproteins focusing in the acidic range which were absent in the Microsporum spp. A characteristic protein of doublet (pI 8.7) was present in the Microsporum spp. and absent in the Trichophyton spp. Analytical isoelectric focusing is a potentially useful method to distinguish inter- and intra-species differences in the pattern of secreted dermatophyte proteins present in culture filtrates and in trichophytins. The information derived may be useful in the classification of species.