We have reported previously that ethyl acetate-extracts from the fruiting body of a Japanese edible mushroom, Buna-shimeji (Hypsizigus marmoreus), exhibited strong anti-tumor activities against tumorbearing mice, and that the main active substance of its extracts was identified as a polyterpene, Hypsiziprenol A_9. Hypsiziprenol A_9 inhibited the growth of various human cancer cell lines. However, its antitumor mechanism has not been studied in detail. To elucidate its mechanism, we examined Hypsiziprenol A_9-induced apoptosis in human promyelocytic leukemia HL-60 cells. Hypsiziprenol A_9 strongly inhibited the growth of HL-60 cells in a dose-dependent manner. Formation of apoptotic bodies was observed within 4 hr of Hypsiziprenol A_9 treatment. Pan-caspase inhibitor (Z-VAD-FMK) attenuated anti-proliferation effect of Hypsiziprenol A_9. Hypsiziprenol A_9-induced apoptosis was strongly inhibited by CAMP analogue (DBcAMP) or by CAMP-eleveting agents (Forskolin and IBMX), whereas p38 MAPK inhibitor (SB203580), JNK inhibitor (SP600125) and calcium chelators (EGTA, BAPTA-AM) had no effect. Thus, these results suggest that Hypsiziprenol A_9 inhibits the growth of HL-60 cells by inducing apoptosis via the down-modulation of CAMP signaling pathway.

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Reutilization of cultural waste of Grifola frondosa as the substrate of bottle cultivation of Hericium erinaceum was investigated. Using the cultural waste with Japanese beech (Fagus crenata) or Japanese oak (Quercus serrata, Quercus mongolica var. grosseserrata) sawdust yielded increases in fruit bodies of H. erinaceum relative to increases in its substitutive ratio. The yields of fruit bodies on cultural waste medium of G. frondosa were significantly increased by 1.2- or 1.3-fold compared with that on either the beech or oak sawdust medium, respectively. The optimal ratio of nutrition for cultivation in the cultural waste medium was determined to be 40-50%. Compared with cultivation using fresh cultural waste medium, cultivation using medium containing cultural waste aged for 28-56 days at 15 or 25 ℃ or aged for 14-28 days at 35℃ yielded a 1.1- or 1.2-fold increase in fruit bodies, respectively. These results suggest that cultural waste of G. frondosa may be useful as a substrate for sawdust based cultivation of H. erinaceum.

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From bag-culture of sawdust-based cultivation of Lentinula edodes, 17 substrates considered to be abnormal were collected. These substrates were classified into the following symptoms: browning defect (4 strains), white mycelial mat on the surface (8 strains), and abnormal hard knot on the surface (5 strains). In addition to the 17 strains isolated from these abnormal substrates, we examined 29 normal strains from our laboratory stock. Cultured mycelium was ground in phosphate buffer and virus particles were precipitated by adding polyethylene glycol 8000 and NaCl. Following phenol extraction of the virus particles, double-stranded RNA (dsRNA) was detected in 2 strains by agarose gel electrophoresis; one was from a normal strain and the other was from an abnormal strain with browning defect.

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Soybean milk was inoculated with mushroom Schizophyllum commune (NBRC 4928) and fermented at 37℃ for 6 weeks. After one week of fermentation, SDS-PAGE patterns of fermented soybean milk showed protein bands that either reduced or disappeared, as well as new bands that appeared. Total free amino acid content of fermented soybean milk after three weeks of fermentation was 8914mg/100ml; varying patterns for oxalic, malic, succinic and pyroglutamic acids appearing and disappearing were observed during fermentation. Both antioxidative and antithrombic activities in fermented soybean milk increased with the progress of fermentation.

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Weeds (non-crop herbs) are unseasonably obtainable biomasses. To evaluate the potential of weeds as mushroom cultivation medium, cultivation properties of basidiomycetes using weeds were investigated. A total of 32 species of basidiomycetes and 13 species of weeds was used in this investigation. Each fungus was inoculated to the solid medium made by each weed, and mycelial growth was measured. On medium of Lolium multiflorum, a Gramineae family plant, mycelial growth of 10 of 29 fungi were larger than 100mm within 28 days; on 3 other species of Gramineae, it was also fast. Fungi of the family Pleurotaceae such as Pleurotus cornucopiae var. citrinopileatus and wood decay fungi of the order Aphyllophorales such as Ganoderma lucidum grew comparatively fast on almost all 13 species of weeds.

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In this study, we screened for antioxidant activity on a variety of fungi kept in our laboratories, the ethyl acetate-methanol extracts of the mycelia of 174 mold species (228 strains) and the colony of 1 yeast species (1 strain) cultured on agar slant media and methanol extracts of the fruit bodies of 81 mushroom species collected from various locations in Japan and 2 cultivated mushroom species. From both ordinary and reversed phase TLC analysis, the extracts from 23 species (25 strains) of molds (Ascomycota) and from 23 species of mushrooms (Basidiomycota) showed obvious 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity. Among the 23 mold species with potent antioxidant activity, 11 species (12 strains) belong to the genus Eurotium. Overall, the ratio of the number of species with potent activity to the total number of sample species was higher in mushrooms (27.7%) than in molds (13.2%).

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