Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme V: CELL BIOLOGY AND PHYSIOLOGY Posters
produce lolines under certain culture conditions, and a
culture system was developed for regulated loline
expression in this fungus. With this system, genes
differentially expressed during loline accumulation were
isolated by subtractive hybridization. Two genes isolated,
lolA and lolC, were similar to genes encoding aspartate
kinases and homocysteine synthase, respectively, which are
enzymes in methionine biosynthesis. lolA and lolC were
highly expressed during loline production in culture, and
the two genes were present only in endophytes with lolineproducing
phenotypes. Close linkage of lolA and lolC in N.
uncinatum was found by PCR, corroborated by data from a
genomic library survey of the closely related endophyte E.
festucae. At least five putative genes were found clustered
with lolA and lolC. These putative genes have similarity to
polyamine biosynthesis/interconversion genes, and genes
for monooxygenases, oxidoreductases, demethylases and
aminotransferases, which are frequently found in
secondary-metabolite gene clusters.
1183 - Vacuolar and non-vacuolar protein degradation
routes in the white-rot fungus Phlebia radiata: their
influence on ligninolytic enzymes
M. Staszczak 1 , I. Glina 2 , A. Leonowicz 1 & K.
Grzywnowicz 1*
1 Department of Biochemistry, Maria Curie-Sklodowska
University, Pl. M.Curie- Sklodowskiej 3, 20-031 Lublin,
Poland. - 2 Department of Cell Biology, Maria Curie-
Sklodowska University, ul. Akademicka 19, 20-033 Lublin,
Poland. - E-mail: grzyw@hermes.umcs.lublin.pl
Continuous protein turnover is involved in basic cellular
functions such as the modulation of the levels of proteins,
adjustment to stress, as well as preferential removal of
defective proteins. Eukaryotic cells contain two major
systems for protein degradation: lysosomal (vacuolar) and
non-lysosomal (non-vacuolar). The lysosome was long
believed to be the only site for protein breakdown in cells,
but it is now clear that intracellular proteolysis is largely
accomplished by a highly selective non-lysosomal pathway
that requires a large multicatalytic proteinase complex
known as the proteasome. The 26S eukaryotic proteasome
catalyses the ATP-dependent degradation of
polyubiquitinated proteins. Lignin-modifying enzymes of
white-rot fungi are mainly expressed during the secondary
phase of growth (idiophase), when the limitation of carbon
and nitrogen occurs. It has been demonstrated for many
eukaryotic organisms, that both the vacuolar and nonvacuolar
proteolytic systems are activated by nutrient
starvation. A major goal of the present study was to
examine whether the specific agent (CbzLLLal, MG 132)
that blocks the function of yeast and mammalian 26S
proteasome and the lysosomotropic agent inhibiting
intralysosomal degradation of proteins (chloroquine) can
affect the levels of ligninolytic enzymes of the white-rot
fungus Phlebia radiata during the shift to idiophase
triggered by nitrogen or carbon starvation. Supported by
the EC Contract ICA2-CT-2000-10050, 5PR-UE/DZ
280/2000.
1184 - Degradation of natural and artificial humic acids
by the litter-decomposing basidiomycete Collybia
dryophila
K.T. Steffen 1* , M. Hofrichter 1 & A. Hatakka 2
1 Department of Applied Chemistry and Microbiology,
P.O.Box 56, Viikinkaari 9, Bicenter 1, FIN-00014
University of Helsinki, Finland. - 2 Dep. of Environmental
Biotechnology, International Graduate School Zittau,
Markt 23, D-02763 Zittau, Germany. - E-mail:
Kari.Steffen@Helsinki.Fi
The litter decomposing fungus Collybia dryophila is a
common basidiomycete colonizing different types of forest
soils. It decomposed in our experiments a natural humic
acid isolated from pine-forest litter (LHA) and a synthetic
14 C-labeled humic acid ( 14 C-HA) prepared from [UL-
14 C]catechol in liquid culture. Polar, lower-molecular mass
fulvic acid (FA) and carbon dioxide were formed during
the degradation. Manganese (200 µn; M Mn 2+ ) enhanced
considerably the decomposition of HA leading to 75%
conversion of LHA and 50% mineralization of 14 C-HA
compared to 60% and 20%, respectively, in the absence of
Mn 2+ . These findings strongly indicated an involvement of
the ligninolytic enzyme manganese peroxidase (MnP), the
production of which was noticeably increased in Mn 2+ -
supplemented cultures and which was found to be capable
of converting LHA in vitro. The enzyme was produced as a
single protein with a pI of 4.7 and a molecular weight of 44
kDa. In solid-state culture (pine-forest litter), C. dryophila
mineralized 14 C-HA as well and released substantial
amounts of water-soluble FA from the insoluble litter
material. The results indicate that litter-decomposing
basidiomycetes such as C. dryophila are involved in humus
turnover by recycling high-molecular mass humic
substances.
1185 - Ultrastructural analysis of sterile elements of
basidiomes and fruitbodies in holobasidiomycetes
A.A. Stepanova
National Institute of Desert, Flora and Fauna Ministry of
Nature Protection Of Turkmenistan,
Ashgabad,744000,Bitarap Turkmenistana,15,
Turkmenistan. - E-mail: iccnet@onlinee.tm
Comparative ultrastructural analysis of morphogenesis of
sterile elements of basidiomes (B) in 6 species of the
Aphyllophorales and fruitbodies in 17 of Agaricales and 1
Gasteromycetes showed that the most specialised are the
cells of subhymenium, having the features of meristematic
cells. During the grows of B and FB the cells of sterile
elements are vacuolised, reserve substances, accumulated
in many species, disappear, cytosol and number of
organelles are reduced.For all studied species (expect the
species of Coprinaceae) cells of sterile elements has
ultrasructure indicated of low level of its metabolism. It
was shown, that mass senescence and death of the cells of
Book of Abstracts 359