A protease was purified from the culture filtrate of a plant worm, Paecilomyces farinosus. The activity of the protease was suppressed by serine protease inhibitors such as phenylmethylsulfonylfluoride (PMSF), chymostatin, and N-tosyl-L-phenylalanine chloromethyl ketone (TPCK). Its molecular mass was estimated to be 28 kDa by SDS-PAGE, and its optimal pH and temperature were pH 8.0 and 45℃, respectively. The cDNA encoding the mature serine protease was cloned by a PCR-based method. The mature serine protease sequence consists of 849 bp, encoding 283 amino acid residues. The amino acid sequence shares sequence homology with subtilisin-type serine endopeptidases belonging to the peptidase S8 family from Beauveria bassiana and Metarhizium anisopliae. This result suggested that the enzyme from P. farinosus is a subtilisin-type serine endopeptidase.

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Dacne picta Crotch (Coleoptera: Erotylidae) is a known pest of log-grown shiitake mushrooms (Lentinula edodes). However, adult beetles, which feed on the mushroom fruiting bodies, have recently been observed in sawdust-based cultivation facilities. We examined the growth of D. picta larvae fed on shiitake mycelial blocks. The effect of irrigation frequency and water quantity on larval survival and development were investigated and a pest control protocol was formulated. The larvae developed into adults after feeding on fruiting bodies and mycelial blocks, indicating that they were capable of consuming the mycelial blocks used in the cultivation facilities. Larval survival, rate of development, and adult size could be decreased by controlling the irrigation regime. Moreover, flooding killed approximately 80% of larvae feeding on the mycelial blocks. These results suggest that irrigation frequency and quantity could potentially be used to reduce damage by D. picta.

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Rhizopogon roseolus (Corda) Th. Fr. is an economically important edible mycorrhizal mushroom. We previously developed techniques for artificial cultivation of this mushroom using mycorrhizal pine seedlings, but stable production of fruiting bodies has not been accomplished. Selection of superior strains by crossbreeding is a promising approach to increase the yield of fruiting bodies, which requires genetically diverse homokaryons. To obtain abundant homokaryons from basidiospores, we evaluated the relationship between composition of the agar medium and germination rate of basidiospores as well as vegetative hyphal growth. Five agar medium compositions were prepared as a base for MMN medium. A higher germination rate was observed on diluted MMN medium than on full-strength MMN medium. Additionally, larger colony diameters were observed on diluted MMN medium than on MMN medium. These results implied that the optimum medium for basidiospore germination positively correlated with the optimum medium for vegetative hyphal growth on axenic agar. Among the tested media, 1/5 diluted MMN agar medium was optimum for basidiospore germination and subsequent mycelial colonization of homokaryotic hyphae, showing that this medium was useful for obtaining abundant homokaryons in R. roseolus.

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Cultivation of the mycelia of Schizophyllum commune (NBRC 4928) using bonito soup stock resulted in higher antioxidant activity when compared with mycela cultured in malt medium. Production of ergothionein in mycelia cultured in bonito soup stock culture medium was confirmed. The yield of ergothionein was 1.01 mg per 1 g of dry mycelia and the production per liter of medium was 12.9 mg. The yield of ergothionein per 1 g of dry mycelium was lower when using bonito soup stock; however, the yield per 1 L of medium was higher than reported previously because of the relatively large number of mycelia formed.

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