2021 Fiscal Year Research-status Report
現場調査と研究室実験を組み合わせた原木シイタケのセシウム移行要因解析
| Project/Area Number |
18K05739
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| Research Institution | The University of Tokyo |
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Principal Investigator |
OBrien Martin 東京大学, 大学院農学生命科学研究科(農学部), 特任准教授 (00723595)
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| Co-Investigator(Kenkyū-buntansha) |
二瓶 直登 福島大学, 食農学類, 准教授 (50504065)
田野井 慶太朗 東京大学, 大学院農学生命科学研究科(農学部), 教授 (90361576)
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| Project Period (FY) |
2018-04-01 – 2023-03-31
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| Keywords | shiitake / oak logs / transfer factor (TF) / stable cesium |
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| Outline of Annual Research Achievements |
As reported previously, a higher K concentration in logs was found to decrease the log-to-shiitake TF of Cs-133 (hereafter will be referred to as totCs-133). We have also found that higher K concentrations in logs also decreases the log-to-shiitake TF of exchangeable Cs-133 (hereafter known as exCs-133). We also reported in our previous report that there was a positive correlation between the totCs-133/K ratio in logs and the log-to-shiitake TF. However, there was no relationship observed between exCs-133/K ratio and the log-to-shiitake TF.
We have now analysed the data specifically related to three different strains of shiitake. One strain had a significantly higher log-to-shiitake TF of totCs133 than the other two strains. For one shiitake strain, a higher K concentration in the logs was found to significantly decrease the log-to-shiitake TF of totCs-133 (but not exCs-133), and for the other two strains, no such relationship was observed for either the TF of totCs-133 or exCs-133. There was also no evidence that absorption competition between K and Cs-133 is an important factor for totCs-133 uptake by any of the three shiitake strains. Data related to exCs-133 is still pending.
To understand where shiitake sources Cs-133 from within a log, we found that ~ 70% of the Cs-133 is exchangeable in the wood and ~ 40% is exchangeable in the bark. However, using ergosterol as a measure for metabolically active mycelium, we found 3.5-fold higher amounts of fungal mycelium in the bark compared to in the wood.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Although all the planned laboratory work related to the fieldwork has been completed and most of this data has been statistically analysed, some additional laboratory analysis will be undertaken e.g., measure carbon and nitrogen content in wood and bark samples, etc,. Also, we want to continue to optimise the production of shiitake fruiting bodies in vitro.
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| Strategy for Future Research Activity |
Because the data from different shiitake strains was contradictory, we intend to measure carbon and nitrogen content in all wood and bark samples. A research manuscript is currently being prepared to report the results of the fieldwork.
In addition, we will also continue to optimize the method to produce shiitake fruiting bodies in vitro.
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| Causes of Carryover |
Additional laboratory analysis will need to be undertaken e.g., measure carbon and nitrogen content in wood and bark samples, etc,. Also, we plan to continue to optimise the production of shiitake fruiting bodies in vitro. The funds will be used to purchase all the necessary reagents, chemicals and consumables to perform those experiments, and also for the labor of one technician who will measure carbon and nitrogen content in the samples.
We also plan to publish this research in an international journal, so funds may be required for article processing charges.
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