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Comparative analyses of antigenic and enzymatic characteristics of the genus Trametes (Polyporaceae).
thesisposted on 2023-05-27, 08:13 authored by Cheung, Damon Shung Ming
The taxonomy of the Polyporaceae with emphasis on Trametes versicolor and related species has been studied using comparative analyses of antigenic and enzymatic characteristics of 60 polypore cultures. The system of laccase (p-diphenol: 02 oxidoreductase, E .0 .1.10.3 .2) isoenzymes produced by T. versicolor has been selected for detailed investigation. T. versicolor and some related species produced three laccase isoenzymes which have been named laccase 1, laccase 2 and laccase 3 according to their relative electrophoretic mobilities. The three isoenzymes exhibited identical affinity to catechin (Km = 10 -4M) and a similar substrate specifity, but they were differentially inactivated by sodium diethyldithiocarbamate, extreme H ion concentrations, and urea. At least five different antigenic determinants (a, b, c, d and e) may be present among the three laccases. Laccase 1 (determinants a and d) is antigenically distinct from laccase 2 (b and e). Both these isoenzymes are related to laccase 3 which possesses determinants c, d and e. The antigenic properties, together with the current understanding of the molecular structures of the laccase produced by T. versicolor ,leads to the suggestion that each antigenic determinant (a, b, c, d, or e) may be located on a specific polypeptide unit (Aa , Bb , Cc , Dd , and E e , respectively). Antigenically unrelated proteins exhibiting identical electrophoretic mobilities have been detected during comparative studies of Trametes and an isolate of Aspergillus niger. The results suggest that misclassification of fungi may result from using single enzymes as taxonomic criteria. Results from numerical analyses of 60 polypore cultures and a culture of A. niger based on their enzymatic and antigenic characteristics showed parallelisms between morphological resemblance and similarity in protein characteristics between T. versicolor, T. zonata, T. azurea, T. hirsuta and T. velutina. The quantitative relationships between these fungi and other members of the Polyporaceae (including other Trametes species) do not always agree with the inter-species relationships indicated by current classifications of the family. These differences suggest that detailed study of certain taxa by serological and electrophoretic techniques may lead to alterations in their classification. The taxonomic status of T. cinnabarina has been confirmed. An isolate from the Northern Hemisphere and several from Australia belong to a single species, which in turn belongs to the genus Trametes. It is suggested that international reference centres might be established, where suitable facilities exist to provide serological and electrophoretic analyses of fungal proteins. Such large scale quantitative estimation of relationships between fungi would yield results for an adequate taxonomic revision of the Polyporaceae, and would facilitate accurate identification and classification of newly isolated polypore cultures.
Rights statementThesis (Ph.D) - University of Tasmania, 1969