We investigated the relationship between cesium-137 (137Cs) migration to shiitake <i>Lentinula edodes</i> mushroom fruiting bodies and yield using konara oak (<i>Quercus serrata</i>) logs from two sites with differing 137Cs distribution (ratio) in the inner bark, sapwood, and heartwood. A significant negative correlation was observed between 137Cs concentration of fruiting bodies as standardized by 137Cs concentration of sapwood and yield at three of four harvest times in logs from the two sites with different distributions of log contamination. Therefore, the results suggest that 137Cs concentration of the fruiting bodies is approximately defined by its relationship with 137Cs concentration of sapwood and yield, regardless of the 137Cs distribution (ratio) of logs. In addition, when the yield of each log was low, 137Cs concentration of fruiting bodies tended to be remarkably high in ratio to 137Cs concentration of sapwood, and yield, which can be measured at the production site, may be used as an indicator for countermeasures against radioactive contamination.

View full abstract

We isolated and purified aromatic compounds from water extracts of <i>Grifola gargal</i> and elucidated their structures by instrumental analysis. The results revealed that adenosine was one of the aromatic compounds in the extracts. Moreover, nucleosides (cytidine, uridine, guanosine, and thymidine) in the water extracts from <i>Grifola gargal</i> were identified by high-performance liquid chromatography (HPLC). In addition, the nucleoside contents of water extracts of 17 mushroom species were also identified by HPLC, and their quantitative values were determined by principal component analysis. <i>Pleurotus ostreatus</i> had the highest adenosine content among the tested mushrooms and different mushrooms had different amounts of nucleosides.

View full abstract

Domestic production of <i>Auricularia polytricha</i> (aragekikurage in Japanese) has increased sharply in recent years. Although agronomic research is progressing, more efforts to strengthen domestic productivity are still expected. The authors have shown in previous studies that the incubation period, which is generally 60 days or more, can be shortened to 40 － 50 days by adding an appropriate amount of shell fossil containing calcium carbonate as the main component to the culture medium of A. polytricha. In this study, a hyphal elongation test and cultivation test were conducted using dried soybean curd residue as a substitute for each nutrient material. The addition of the dried soybean curd residue, mainly as a substitute for rice bran, improved hyphal elongation and the yield, and shortened the incubation period from around 60 days to 30 days.

View full abstract