We performed a cladistic analysis of the V4 domain sequences of twelve Lyophyllum shimeji strains and two L. decastes strains by UPGMA methods As a result, we were able to divide these 14 strains into two clusters. Then, we prepared monokaryotic stocks from dikaryotic strains by protoplast monokaryotization for mating compatibility tests. Five monokaryotic stocks from five dikaryotic strains of cluster 1 showed mating compatibility and at least two types of mating stocks were isolated from dikaryotic strains of cluster 2. These mating compatibility results between monokaryotic stocks of clusters 1 and 2 indicate that the biological species of cluster 1 strains are different from those of cluster 2 strains. Therefore, we suggest that the L. shimeji strains in this study include strains from different biological species.

View full abstract

Texture of fruit-bodies of Blao, a Vietnamese strain of Pleurotus cystidiosus subsp. abalonus, cultivated on different component substrates, was evaluated with four indices, brittleness, tenderness, pliability and toughness, by the microdisplacement measurement method using a compression testing instrument. While brittleness increased, tenderness decreased by the incremental change in rice husk or bagasse ratios in the substitutions of sawdust with rice husk or bagasse. The other two indices, pliability and toughness, showed no correlative changes. Fruit-body texture also depended on the substrate supplements rice bran and wheat bran. Brittleness and pliability of fruit-bodies differed significantly between rice bran and wheat bran added as a nutritional supplement to the basal substrate. These changes in fruit-body texture would not be due to changes in their water contents. At 20℃ storage, tenderness and toughness of fruit-bodies tended to be minimum after 2 days' storage, but then increased up to 4 days' storage. Brittleness of fruit-bodies gradually decreased with time of storage, whereas their pliability gradually increased. At 20℃ storage, statistically significant differences in brittleness and pliability were observed only in fruit-bodies stored from 4 to 6 days. At 10℃ storage, changes in fruit-body texture were not detected after 8 days' storage.

View full abstract

To select superior strains of Pleurotus cornucopiae var. citrinopileatus adaptable to practical cultivation systems, we analyzed the characteristics of hybrid strains, including productivity and quality of the fruiting bodies. By comparing with the characteristics of two parental strains, 5 out of 204 different hybrid strains were selected. In the principle component analysis of the coexistence ratio of fruiting bodies with warped pilei, soft lower parts of the stipes, and immature fruiting bodies, we found that three of the selected strains had lower ratios of immature fruiting bodies and fruiting bodies with warped pilei than the control strains, 87-2 and 98-3. The other two strains had a lower ratio of soft lower parts of the stipes than the first three selected strains. These findings indicate that the selected strains had improved characteristics compared to the parental strains. In the fruiting bodies of the five selected strains and one parental strain, we also investigated the content of taste components, such as free amino acids and 5'-GMP. There was a significant difference in free amino acid and 5'-GMP contents among strains, indicating a significant difference in taste between strains. Finally, we performed repeat cultivation tests, and strain 291 was selected from the 5 selected strains for fruiting body production, as it produced fruiting bodies with high quality appearance.

View full abstract

Genomic DNA was extracted from fresh and cooked (i.e., baked, stir-fried, tempura-style fried and boiled) fruiting bodies of fresh and heat-dried Lentinula edodes and from those of fresh, canned and retorted Agaricus bisporus. No degradation of DNA extracted from baked, stir-fried, tempura-style fried fruiting bodies was observed. However, boiling, canning and retorting seemed to influence degradation of DNA samples. These DNA samples were used as templates for PCR amplification of the ITS region using universal and designed specific primer pairs. Specific amplified signals were detected from all DNA samples of fresh and cooked fruiting bodies. All DNA samples of cooked fruiting bodies were amplified using the ITS 5 and ITS 4 primer pair, except for those of fruiting bodies boiled for more than 120 min, canned and retorted. The 〜350bp fragments of the fruiting body samples boiled for more than 120 min were amplified using the ITS 5 and ITS 2 primer pair and the 〜250bp fragments of canned and retorted fruiting body samples were amplified from the designed specific primer pair. All sequences of the amplified fragments were analyzed and no nucleotide substitution caused by cooking was observed.

View full abstract

Changes in the lipids components in the fruit-body of Sparassis crispa during development were investigated. The total lipids contents in primordium, young fruit-body and matured fruit-body were 0.35%, 0.31 % and 0.30%, respectively. The component of each lipid fraction in total lipids, it was found that the contents of neutral lipids (50.8-54.7%) and phospholipids (37.7-41.0%) were high, while that of glycolipids (7.6-11.2%) was low. The main lipids in neutral lipids were triacylglycerol (63.3-67.5%), followed by sterol ester (12.9-15.1 %), sterol (8.6-11.6%), diacylglycerol (4.0-4.8%) and monoacylglycerol (1.0-1.5%). The main lipid in phospholipids were phosphatidylethanolamine (60.4-68.9%), followed by phosphatidyl choline (18.3-20.4%), cardiolipin(8.0-10.6%) and lyso-phosphatidylcholine (4.8-6.0%). Fatty acids components were not significantly different among total lipids, neutral lipids, glycolipids and phospholipids contained in primordium, young fruit-body and matured fruit-body. The main fatty acids were linoleic, oleic and palmitic acid.

View full abstract