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Abstract

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.

Item Type:	Thesis - PhD
Authors/Creators:	Cheung, Damon Shung Ming
Keywords:	Trametes versicolor
Copyright Holders:	The Author
Additional Information:	Thesis (Ph.D) - University of Tasmania, 1969
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