The edible species of the genus <i>Auricularia</i> mainly include <i>A. polytricha</i> and <i>A. auricula-judae</i> (aragekikurage and kikurage in Japanese, respectively). Together these edible mushrooms are ranked 6 th in terms of consumption in Japan. Since most official statistical surveys in Japan do not distinguish between either of these mushrooms species and group them together loosely in the "kikurage group", detailed statistical data for each species do not exist. However, it is clear that <i>A. polytricha</i> accounts for the majority of domestic production in Japan. The supply of <i>A. polytricha</i> has been strongly dependent on imports. Since the risks associated with imported products have increased in recent years, domestic demand has increased and rapid growth in domestic production has occurred. On the other hand, various problems with breeding, cultivation techniques, pest control, taxonomy, and food science have arisen. In addition, possible future threats include erosion of the domestic market by imported culture bags and disguised production areas. In this review, the author will clarify the production trends, current challenges, and future threats with the aim of strengthening and developing domestic production bases in the future.

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To observe biological specimens using scanning electron microscope (SEM), generally, specimens are subjected to fixation, dehydration, and drying to avoid morphological deformation due to the vacuum condition. t-Butyl alcohol freeze-drying is one of the methods for drying specimens, and it is simple and convenient when compared to other methods, such as critical point drying. However, the occurrence of gross shrinkage and cracks on the cell surface is a critical problem when the hymenophore of <i>Pleurotus ostreatus</i> is treated by conventional double fixation with glutaraldehyde and osmium tetroxide (OsO4) followed by t-butyl alcohol freeze-drying. The present study revealed that when the hymenophore was treated by triple fixation with OsO4-tanic acid-OsO4 before t-butyl alcohol freeze-drying, shrinkage and cracks were substantially suppressed, and it was possible to observe the ultrastructure of the cell surface. The intracellular structure of the specimens treated by the triple fixation method was also observed using transmission electron microscope. The significance of the triple fixation method is discussed from both extracellular and intracellular morphological aspects.

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In this study, different parts of <i>Grifola frondosa</i> were analyzed to examine their antioxidant activity and transition metal content. For the examination, the fruiting body was divided into three parts and the medium into two parts. The cap showed the highest antioxidant activity. We found differences in the amounts of transition metals among different parts of the fruiting body. To purify the iron-binding proteins having antioxidant activity, we subjected the cap of G. frondosa to size-separation gel-filtration chromatography. A protein fraction was detected from the obtained chromatogram. This fraction was speculated to represent the iron-binding proteins.

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We identified and characterized a glutamic acid protease gene (<i>GlGLP1</i>) from <i>Ganoderma lucidum</i>. The gene consisted of three exons with a total length of 807 bp containing the start and stop codons. It encoded a 268 amino acid protein containing a signal peptide. The expression level of <i>GlGLP1</i> changed during growth and after harvesting, and was increased in the fruiting body primordia in multiple strains. These results suggest that <i>GlGLP1</i> is involved in processes from mycelium to fruiting body primordium formation. Furthermore, the expression was confirmed by separating the pileus and stipe of the fruiting body. High expression of <i>GlGLP1</i> was confirmed in the pileus part approaching maturity. <i>GlGLP1</i> was also considered to be involved in pileus maturation and sporulation.

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