Basidiocarp and mycelium morphology of Ganoderma lucidum Karst. Strains isolated in Hungary.

Morphological, anatomical and cultural characteristics of 14 Ganoderma lucidum (Fr.) Karst strains isolated in Hungary have been investigated. Macroscopically the basidiocarps of the Hungarian strains are absolutely identical with those of described previously about the Ganoderma lucidum species-complex. Microscopic features of the fruitbodies and basidiospores showed some differences from the typical G. lucidum species. Pilocystidia, forming a homogeneous layer on the surface of the pileus, have smooth heads without protrusions and stalks not ramifying. Cell wall pillar density and width of the basidiospores also differ from that of regarded to be characteristic to G. lucidum. Although according to several authors chlamydospore formation is a characteristic feature of G. lucidum it has not been observed in mycelial cultures of the Hungarian strains. Antagonistic reactions between the Hungarian and Far Eastern G. lucidum isolates were mostly similar to the interspecific reactions between the two species G. lucidum and G. applanatum and corresponded only in a few cases to the interactions within one species. Our results suggest that the Hungarian strains significantly differ from the Far Eastern strains. To determine the taxonomic degree of this divergence genetical examinations should be carried out.

A simple and rapid semiquantitative method for measuring cellulase activity in agar media.

A simple and rapid semiquantitative technique for the determination of fungal cellulytic activities in solid (agar slant) media has been developed. This method is a combination of Congo-red staining widely used for qualitative cellulase detection and common cellulase activity tests. Previous investigation on the adsorptive effect of cellulose content of media showed that the real enzyme activity values can be measured with minimum loss by means of agar discs cut from the most active zones of slants visualized by Congo-red staining. Different cellulase activity tests (FPase, CMCase and beta-glucosidase by PNPG-method) of seven cellulolytic fungal strains were investigated by this technique. Data give information on the different enzyme profiles of the species. The method can be regarded as very simple and suitable for simultaneous rapid comparison of cellulase components of greater series of fungal strains from agar slant cultures. It can also be used in the case of fungi unable to grow in liquid cultures.

Some characteristics and partial purification of the Ganoderma lucidum cellulase system.

The extracellular cellulase system of the white-rotting basidiomycete Ganoderma lucidum was characterised while growing in cellulose-containing shaken liquid culture. The protein content of the culture filtrate reached its maximum after 36 days and cellulase activity at about 60 days. Different cellulase activities (endoglucanase, cellobiohydrolase and beta-glucosidase) were determined in a range of pH extending from 6 to 2. All of the three enzyme activities have at least three peaks between pH 6 and 2, although optimum points of the different enzymes are slightly different, showing that the enzyme complex consists of a number of enzymes and isozymes. Partial purification of the enzyme complex was carried out by DEAE-cellulose column chromatography. Using 0-3 M linear urea gradient, protein was eluted in one sharp peak corresponding mainly to beta-glucosidase activity. Comparing crude extracellular protein with that of purified by the column using PAGE indicated that this method was suitable for the separation and partial purification of one type of Ganoderma cellulases.

Effect of a new fungicide (PNDP) on the minor nucleotide content of Fusarium oxysporum.

The minor nucleotide constituents of rRNA from the plant pathogenic fungus Fusarium oxysporum were investigated. When the fungus was grown for 8 days in aerated liquid culture the following minor nucleotides were identified from 18S and 25S rRNA: m6A, m2A , m2(6)A, m1G, m2G , m2(2)G, m3C , Cm, m5C, m3U , Um, cm5U , rT and psi. PNDP (+/- threo-1-phenyl-2-nitro-1,3 diacetoxy-propane), a new fungicide of unknown biochemical mode of action, caused a great decrease in the minor nucleotide content of the fungus. Only seven minor nucleotides were present in the rRNA of the fungus grown in PNDP -containing medium. A hypermodified nucleotide, mcm5S2U , was found in treated but not in untreated fusarium. On comparing the effect of PNDP with that of known protein synthesis inhibitors such as cycloheximide and chloramphenicol, it was concluded that PNDP acted similarly to cycloheximide, a cytoplasmic protein synthesis inhibitor. It is suggested that the mode of action of PNDP may be the inhibition of the synthesis of RNA modifying enzymes of F. oxysporum.