In this study, we optimized culture conditions and methods for producing ergothioneine yields by the basidiomycete, Schizophyllum commune (NBRC 30749). Mycelium cultivation was carried out by shaking at 25℃ for 42 days in bonito soup stock. In addition, a malt culture medium made with bonito soup stock that is commonly used for mycelial culture was used as a control. In addition to a multi-bead shocker that is conventionally used to disrupt mycelia, we incorporated a pestle and a mortar step, which was particularly effective in increasing ergothioneine yields. The supernatant obtained by centrifugation was used as a cell-free extract, and the ergothioneine content was measured by HPLC. The optimal conditions for ergothioneine production comprised rotational shaking of the basidiomycete culture for 42 days in a culture medium with a glucose concentration of 3% and an amino acid and a yeast extract added to bonito soup stock. Further improvements in ergothioneine yields are expected through modification of culture conditions, additives and culture period.

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We clarified optimal culture conditions of Omphalotus japonicus and Neonothopanus sp. mycelia, representative luminous fungi in the temperate and subtropical regions of Japan, respectively. The best growth conditions for the two species were the same; incubation in a medium with 40 g dextrin and 1 g yeast extract per L at pH 5.0 and 30℃ for 14 d. Under these conditions for the best mycelial growth, the luminous intensity of O. japonicus was 5.7 times stronger and that of Neonothopanus sp. was 46.5 times stronger than in potato dextrose broth medium, and the luminous intensity of O. japonicus was 6.6 times stronger and that of Neonothopanus sp. was 3.3 times stronger than on potato dextrose agar medium at pH 5.0 and 30℃ for 14 d.

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The detailed microstructure of the ectomycorrhizas formed in Pinus thunbergii roots inoculated with Rhizopogon roseolus was investigated using three-dimensional (3D) image analysis. When P. thunbergii seedlings were artificially inoculated with dichotomous R. roseolus, ectomycorrhizas appeared in seedling roots at 4 weeks after inoculation. The resulting ectomycorrhizas were used to prepare microscopic specimens for light microscopy observation. Using the serial sections, 3D images of Hartig net cells were constructed. The Hartig net cells were highly branched, and certain cells were common in mantle sheath and Hartig net. A constructed 3D image of mantle cells revealed that the outermost cells were cylindrical and the innermost cells were irregularly shaped. Cell volume measurements from the 3D image analysis revealed that the single cell volume of the most exterior and interior mantle sheaths, and the Hartig net measured 365, 452, and 1,516 μm3, respectively. This is the first case report on the 3D analysis of the cell volume of mantle and Hartig net cells in ectomycorrhizas.

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We tested the effectiveness of aeration for the growth of the termite mushroom Termitomyces eurrhizus in a liquid culture. Two aeration treatments, ventilation and shaking, were employed, and the mycelial mass in both treatments increased significantly compared to the controls. However, in both treatments, the mycelial mass tended to decrease from 2 weeks to 4 weeks, suggesting that new methods for promoting long-term culture, such as culture methods that suppress autolysis, are required for the sustainable production of this mushroom species.

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