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Suno, Hiroya; Okumura, Masahiko; Machida, Masahiko
Jiban Kogakkai-Shi, 67(10), p.34 - 35, 2019/10
no abstracts in English
, K, and Na in gas and aqueous phasesSuno, Hiroya; Machida, Masahiko
Chemical Physics Letters, 730, p.26 - 31, 2019/09
Times Cited Count：1 Percentile：4.21(Chemistry, Physical)We perform quantum chemical calculations for the Cs, K, and Na complexes of norbadione A (NBA), a pigment molecule in mushrooms known to accumulate Cs. A numerical two-step approach, by Ota 
, is employed to examine its alkali-metal-cation complexation selectivity in aqueous solutions. Applying it to the neutral, di- and tetra-deprotonated NBAs, we confirm that the complexation selectivity on Cs emerges only in high pHs, in which the di-protonated NBA dominates, in agreement with experimental results. This is the first demonstration of the approach for a biological molecule whose selectivity is known to be anomalous.
Onuki, Toshihiko; Sakamoto, Fuminori; Kozai, Naofumi; Namba, Kenji*; Neda, Hitoshi*; Sasaki, Yoshito; Niizato, Tadafumi; Watanabe, Naoko*; Kozaki, Tamotsu*
Environmental Science; Processes & Impacts, 21(7), p.1164 - 1173, 2019/07
Times Cited Count：10 Percentile：44.69(Chemistry, Analytical)The fate of radioactive Cs deposited after the Fukushima nuclear power plant accident and its associated radiological impacts are largely dependent on its mobility from surface soils to forest ecosystems. We measured the accumulation of radioactive Cs in the fruit bodies of wild fungi in the forest at Iidate, Fukushima, Japan. The transfer factors (TFs) of radioactive Cs from soil to the fruit bodies of wild fungi were between 10 
to 10
, a range similar to those reported for the fruit bodies collected in Europe after the Chernobyl accident and in parts of Japan contaminated by nuclear bomb test fallout. Comparison of the TFs of the wild mushroom and that of the fungal hyphae of 704 stock strains grown on agar medium containing nutrients and radioactive Cs showed that the TFs of wild mushroom were lower. TF was less than 0.1 after addition of the minerals zeolite, vermiculite, phlogopite, smectite, or illite of 1% weight to the agar medium. These results indicate that the presence of minerals decrease Cs uptake by fungi grown in the agar medium.
Onuki, Toshihiko; Aiba, Yukitoshi*; Sakamoto, Fuminori; Kozai, Naofumi; Niizato, Tadafumi; Sasaki, Yoshito
Scientific Reports (Internet), 6, p.29866_1 - 29866_6, 2016/07
Times Cited Count：10 Percentile：31.37(Multidisciplinary Sciences)We here first report the direct accumulation pathway of radioactive Cs from contaminated wood logs to the fruit-bodies of shiitake mushrooms through the basal portion of the stipe by using 
spectroscopy, autoradiography, and X-ray micro CT techniques.
Sakamoto, Fuminori; Onuki, Toshihiko; Kumata, Atsushi*; Hasegawa, Takanori*
no journal, ,
no abstracts in English
Sakamoto, Fuminori; Kozai, Naofumi; Shiina, Kazuhiro; Tanaka, Kenji
no journal, ,
no abstracts in English
Onuki, Toshihiko; Sakamoto, Fuminori; Kozai, Naofumi
no journal, ,
For developing suppression materials of transfer of radioactive Cs to edible mushroom, growth experiments of filamentous fungi with minerals were performed. The mixture containing zeolite is the best to suppress the transfer.
Sakamoto, Fuminori; Onuki, Toshihiko; Kozai, Naofumi
no journal, ,
no abstracts in English
Onuki, Toshihiko; Sakamoto, Fuminori; Kozai, Naofumi; Tanaka, Kenji; Namekawa, Jun; Yamasaki, Shinya*
no journal, ,
We used the spent mushroom substrata (SMS) which is kinds of waste after growing edible mushrooms for the in-situ remediation experiments in Fukushima. We found that the SMS accumulates radioactive Cs not only from the contaminated soil and litter, but from through fall.
Sakamoto, Fuminori; Kozai, Naofumi; Tanaka, Kazuya
no journal, ,
no abstracts in English
Sakamoto, Fuminori; Kozai, Naofumi; Tanaka, Kazuya
no journal, ,
no abstracts in English
Cs using mushroom mycelium and mineralsSakamoto, Fuminori; Kozai, Naofumi; Tanaka, Kazuya; Grambow, B.*
no journal, ,
Six years have passed since the Fukushima Daiichi Nuclear Power accident. However, the decontamination of the forest area remains almost untouched. To develop an effective decontamination method for Fukushima forest soils, we first devised the method to estimate radioactivity of Cs-137 accumulated in fungal mycelium through testing Cs-137 accumulation by about 1500 strains of fungi and then prepared a flat decontamination bag composed of nutrient media, the fungal mycelium with a high Cs-137 accumulation efficiency, and a mixture of zeolite, vermiculite and phlogopite. The decontamination bag accumulated Cs-137 from the contaminated soil in Fukushima forest. Without the minerals, the accumulated Cs-137 was released to the environment after the death of the mycelium. By the addition of the minerals, the Cs-137 in the mycelium was stably fixed by the minerals after the death of the mycelium.
Sakamoto, Fuminori; Guido-Garcia, F.; Tanaka, Kazuya; Kozai, Naofumi
no journal, ,
As a part of elucidation study of the radiocesium circulation mechanism in a forest, this study is aimed for a biochemical elucidation of radiocesium accumulation in a mushroom. The behavior of Cs accumulation in mycelium on the culture process using some mushrooms which are identified their species. As a result, it is cleared that accumulation ratio of Cs are different if the mushroom strain is different, even if the species are same. In this study, we discuss the participation of the biochemical reaction, especially protein on Cs transportation and accumulation in mushrooms.
Guido-Garcia, F.; Kimura, Tatsuki*; Sakamoto, Fuminori; Kozai, Naofumi; David, K.*; Grambow, B.*; Haruma, Toshikatsu; Yamaji, Keiko*
no journal, ,
Mushrooms (fungi) accumulate radiocesium from soil and believed to control Cs circulation in forest. To elucidate mechanism of fungi-involving radiocesium circulation in forest, we investigated dissolution of mineral by a fungus mycelia (Phlebiopsis gigantean) and local concentration ratios of cesium to potassium, Cs/K, in fruit body of Lentinula edodes (shiitake). The tested fungus has higher ability than a siderophore-producing bacterium to dissolve minerals. Most of the Fe dissolved from minerals were found to be not stable complexes with organic substances. Cs/K values were almost constant in same fruit body specimen of shiitake, revealing that cesium is stored in proportion to potassium at any locations of a shiitake fruit body and there is no specific binding site for cesium in shiitake.
)Sasaki, Yoshito; Itabashi, Yasuhiro*; Shigihara, Takashi*; Kurikami, Hiroshi; Niizato, Tadafumi
no journal, ,
Radionuclides were released into the environment due to the accident at the Fukushima Daiichi Nuclear Power Station. Radiocesium, which has a long half-life, remains in the forest, which occupies about 70% of the prefecture's land in Fukushima Prefecture. Mushrooms, which are one of the forest products, are known to easily transfer radiocesium to their fruiting bodies. We report the results of a culture test using the basidiomycete oyster mushroom to clarify the mechanism of radiocesium transfer to the fruiting body.
