A basidiomycetous wood rotting fungus Pleurocybella porrigens (angel wings) has been well known as an excellent edible mushroom and named as Sugihiratake, in Japanese common name based on its morphological and ecological features. This mushroom has been favorably consuming by Japanese people. In 2004, an outbreak of serious acute encephalopathy exclusively occurred in patients with chronic kidney diseases after the intake of this mushroom. Thereafter, many researchers have conducted to examine the factor of onset of the encephalopathy, but the exact factors that induced the encephalopathy still remain unclear. Matsumoto et al. (2005) reported the mushroom specimens from different geographical areas in Japan were grouped into two distinct clusters based on ITS rDNA sequences. Vegetative growth of P. porrigens is extremely slow even cultivation on natural media surveyed and its physiological characteristic gives a disadvantage for the development of various fields of researches on this mushroom. Thus, we attempted to find a medium accelerating the vegetative growth of P. porrigens for further research to elucidate the possible association between its chemical constituent(s) and the onset of encephalopathy. Fifteen isolates of P. porrigens collected from different geographical areas in Japan were cultivated on PDA. The growth of the isolates was extremely slow as we know and most tested isolates formed mycelia look like those often observed in the cultivation of basidiomycetous ectomycorrhizal fungi. Among them, we chose five isolates based on the ranking of their higher growth rates. The top five isolates were cultured in five kinds of liquid media, PD medium, MY medium, Carrot medium, Ohta’s medium for ectomycorrhizal fungi (Ohta, 1990) and Amazake medium (Ishihara, 2007), and on a solid medium, PDA, at 20℃ in the dark. The dry biomasses of the isolates cultured in the liquid media were determined after 6 weeks of the stationary cultivation whereas the growth rates of the isolates cultured on PDA were compared by the colony diameter after 8 weeks of the cultivation. Among the tested liquid media, PD medium was the most suitable medium for their biomass growth (17 mg dry mycelium/flask - 127 mg dry mycelium/flask) and followed by Ohta’s medium (13 mg dry mycelia/flask - 79 mg dry mycelia/flask), MY medium (10 mg dry mycelium/flask - 72 mg dry mycelium/flask), Amazake medium (8 mg dry mycelium/flask - 47 mg dry mycelium/flask) and Carrot medium (4 mg dry mecelium/flask - 18 mg dry mycelium/flask). The average biomass growths of the isolates cultured in the synthetic medium, Ohta’s medium were 20-92% of those of the isolates cultured in PD medium. No correlation was observed between the cultivation in PD medium (liquid medium) and that on PDA (solid medium). Extremely large biomass variation was observed among the same isolates cultured on the same kind of the liquid medium. Large variation in colony features associated with their growth rates was also observed among the isolates cultured on PDA. These results suggest that PD medium would be a suitable one for most researches and Ohta’s medium for researches requiring clarity of its chemical constituents. The above results also indicate that the Japanese population of P. porrigens has large variation in vegetative growth although we have not yet examined whether the tested isolates comprise cryptic species or not.

Addition of ammonia or any nitrogenous materials to the soil that release ammonia causing alkaline condition during decomposition stimulates the fruiting of a particular chemoecological group of fungi, called ammonia fungi (Sagara 1975). The study of ammonia fungi by artificial application of urea in forest soil has been done in diverse geographical regions such as in Japan, Taiwan, New Zealand, Western Australia, and UK. Up to date about 70 species of ammonia fungi have been recorded in those regions. However, ammonia fungi in the boreal forest of American continent have not yet been investigated. Thus, we collected the soils of A0 and the upper layer of HA horizons in plant pots from aspen forest near Edmonton, Canada. Thereafter, we applied urea (granular fertilizer; 46% nitrogen, 10 mg/g dry soil) in plant pots and incubated at 25˚C under 12 hours dark and light regime. After 40 days of incubation, several basidiomata of Coprinopsis species appeared. Among them one specimen was identified as C. rugosobispora based on macro- and microscopic features. Morphologically this species was very similar to C. phlyctidospora which was characterized by warty, ovoid basidiospores, and diverticulate veil elements. C. phlyctidospora has 4-spored basidia while C. rugosobispora had only 2-spored. In the beginning, it was thought probably it was only a 2-spored form of C. phlyctidospora. The basidiospore of C. rugosobispora (9.8-11.7×8.3-9.6㎛) was distinctly larger than that of C. phlyctidospora (8.4-10.6×6.0-7.6 ㎛). It was therefore separated from the C. phlyctidospora. Furthermore in this study we investigated its phylogenetic relationship based on the nuclear rDNA sequence in ITS regions and mating reactions among its close allies and further confirmed it as a distinct species. This is the first record of C. rugosobispora from American continent since it has been collected only from Europe (Belgium and Netherlands). Although urea effectively stimulated its occurrence but it has not yet been reported any other urea application studies so far. This indicates it is a new record in ammonia fungi as well.

The effect of CO2 concentration (500, 3,000, 6,000㎕/ℓ) on the mycelial growth and fruit body primordium formation of Ganoderma lucidum on nutrient agar medium was examined. Optimum CO2 concentration for vegetative growth was above 3,000㎕/ℓ. Fruit body initiation was accelerated at higher than 3,000㎕/ℓCO2 exposure but the maximum number and size of primordia, and primordium color were not influenced by CO2 concentrations. Whereas each atypical fruiting structure forming stock culture showed different fruiting time under each concentration of CO2 exposure.