The glucoamylase gene (PnGlu1) from Pholiota microspora was amplified and characterized. The 1743-bp coding region of PnGlu1 encoded a polypeptide consisting of 581 amino acids with a signal peptide comprising 17 amino acids at the N-terminal. The deduced protein sequence has a two-domain structure consisting of an N-terminal domain with the glycoside hydrolase family 15 signatures and a C-terminal carbohydrate-binding module 20. Southern blot analysis revealed that only a single copy of PnGlu1 was present in the haploid genome of P. microspora. To investigate the capability of starch utilization in P. microspora, PnGlu1 expression level has been examined on minimal media containing different carbon sources such as glucose, soluble starch, corn starch, wheat starch, and potato starch. Quantitative reverse transcription-polymerase chain reaction showed that corn starch and soluble starch strongly stimulated the PnGlu1 gene expression of P. microspora.

View full abstract

A detecting medium, TM7 medium, was developed for the rapid observation of clamp formation as an indicator of secondary mycelia in Rhizopogon roseolus. The TM7 medium contained 0.2% (w/v) Tween 80, 0.1% (w/v) malt extract, and 2% (w/v) agar, with pH adjusted to 7.0 with 1 M NaOH. When tissue culture and basidiospore isolates were cultured on TM7 plates keeping medium sides downward (upside down), clamp formation was consistently observed in the tissue culture isolates at 5 days after inoculation, but never in the basidiospore isolates. These results suggest that the TM7 medium developed in this study may be useful for distinguishing primary and secondary mycelia in R. roseolus.

View full abstract

We analyzed antioxidant activity in several edible mushrooms by crocin bleaching assay, Folin-Ciocalteu assay and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. Among 9 species of edible mushrooms (Agaricus bisporus, Flammulina velutipes, Grifola frondosa, Pleurotus pulmonarius, Lentinula edodes, Agrocybe cylindracea, Hypsizygus marmoreus, Pleurotus eryngii, Hericium erinaceus), A. bisporus had the highest antioxidant activity (0.22 mmol Trolox equivalent/g fresh weight) as analyzed by crocin bleaching assay; this antioxidant activity was found to be heat stable. The antioxidant activities differed depending on the extraction solvent and measuring method used, suggesting that several antioxidants are contained in the mushrooms.

View full abstract

The formation of ectomycorrhizas of Tricholoma matsutake on somatic plants of three pine species (Pinus densiflora, Pin. thunbergii and Pin. taeda) was described. Mycorrhizas, which were similar to those previously reported on pine seedlings, formed on somatic pine plants in sterilized pumice supplemented with a nutrient solution containing glucose, dry yeast and FeCl_<3->. The shoot growth of the pine plants improved after mycorrhizal formation, whereupon the root to shoot ratio of the plant decreased. Mycorrhizal somatic pine plants can assist a molecular approach for investigating the metabolic mechanisms underlying symbiotic relationships between plants and mycorrhizal fungi.

View full abstract