Handbook Part 2 - International Mycological Association

PS4-428-0568
Proteolytic activity of several Coprinoid mushrooms
S.M. Badalyan 1, U. Kües 2, H.K. Avetisyan 1
1 Yerevan State University, Laboratory of Fungal Biology and Biotechnology, Yerevan, Armenia, 2 Georg-August-
University of Göttingen, Institute of Forest Botany, Section Molecular Wood Biotechnology, Göttingen, Germany
Many fungi including basidiomycetes mushrooms produce extra-cellular proteolytic enzymes of great commercial
importance. Several of these fungi can be used in food and medicinal industry to obtain milk-coagulating, proteolytic,
thrombolytic and fibrinolytic biotech-products. Enzymatic complexes with caseinolytic, milk-coagulating, fibrinolytic
and thrombolytic activities produced by Coprinoid mushrooms have been reported before by Denisova (1990).
Physiological and enzymatic activities of Coprinoid mushrooms are however still insufficiently studied.
Different levels of milk-coagulating abilities in Coprinellus micaceus, C. disseminatus, C. xanthothrix, Coprinopsis
cinerea, C. radiata, and C. strossmayeri were detected in our studies. During mycelial cultivation, proteolytic enzymes
are secreted into cultural broth. Proteolytic enzymes also accumulate in fruiting body tissues. Proteolytic activities of
malt- extract culture liquids and of mycelium of various species were investigated for their proteolytic activity on
defatted milk by coagulation and peptonization tests after 5 days of incubation.
Tested culture liquids showed different degrees of proteolytic activities but there was no significant correlation to
fungal cultivation times. However, the doze/effect correlation was noted. Strong proteolytic activity was revealed in
culture liquids from C. micaceus, C. xanthothrix and C. cinerea starting from the first day of incubation whereas
mycelial extracts of these species were inactive. A weaker activity compared to culture liquid samples was detected.
In contrast, in mycelial extracts of C. radiat‡, C. disseminatus and C. strossmayeri proteolytic activities were detected
that were however weaker than the activities in the culture liquids.
This work is supported by grants from the NATO (#980764) and the DAAD (#548.104401.174) grants and by the
Deutsche Bundesstiftung Umwelt (DBU).
PS4-429-0573
The histidine kinase Dic1p regulates HOG1-MAPK involved in glycerol accumulation of Cochliobolus
heterostrophus.
A. Yoshimi, K. Izumitsu, C. Tanaka
Laboratory of Environmental Mycoscience, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
In Southern corn leaf bright fungus Cochliobolus heterostrophus, the histidine kinase Dic1p is involved in resistance to
dicarboximide and phenylpyrrole fungicides. We previously reported that the phenylpyrrole fungicide fludioxonil and
the dicarboximide fungicide iprodione misled to activation of Hog1-type MAPKs in some phytopathogenic fungi
including C. heterostrophus. To elucidate the relationships and functions of C. heterostrophus BmHog1p (Hog1-type
MAPK) and the histidine kinase Dic1p, the phosphorylations of BmHog1p and glycerol-accumulation were analyzed
in the wild-type, the dic1 deficient and the Bmhog1 deficient strains. In the wild-type strain, the phosphorylated
BmHog1p was detected after exposure to both iprodione and fludioxonil, even at concentration of 1 µg/ml. In the
dic1 strain, no phosphorylated BmHog1p was detected after exposure to 1 µg/ml and 10 µg/ml of the fungicides.
Similarly, in response to osmotic stress (0.4 M KCl), a phosphorylated BmHog1p was also not found in the dic1 strain,
whereas the band representing the active BmHog1p was clearly detected in the wild-type strain. The treatments with
iprodione and the osmotic stress caused intracellular glycerol accumulation in the wild-type strain but not in dic1 and
Bmhog1 strains. These observations suggested that the Dic1 histidine kinase positively regulates Hog1-type MAPK,
resulting glycerol accumulation for osmotic adaptation of C. heterostrophus.
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