Large-scale sampling and radioactivity analysis of agricultural soil and food during nuclear emergencies in Japan : Variations over time in foodstuffs inspection and sampling

The measurement of radioactivity in food and agricultural ecosystems is an essential task for keeping the population safe after a nuclear emergency. Prior to the Tokyo Electric Power Company's Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in 2011, the probability of such an accident, combining complex effects of natural and technical factors, was not reflected in detail in national emergency preparedness guidelines. The lack of such guidelines resulted in a limited efficiency response to the Fukushima accident in agriculture. This outcome showed a need for the preparation of such guidelines as a part of emergency preparedness for nuclear and radiological emergences. This paper provides information and generic, non-country-specific guidance on approaches to sampling food. The paper is intended for scientists, policy makers and decision makers involved in nuclear emergency preparedness and responses, particularly on large scales and at different stages of nuclear emergency based on lessons learned from the FDNPP accident

Metabolite profiling and assessment of metabolome compartmentation of soybean leaves using non-aqueous fractionation and GC-MS analysis

In the present study, non-aqueous fractionation (NAQF) and GC-MS were used to obtain a spatially resolved view of metabolism in mature leaves of soybean (Glycine max Merr.). NAQF of lyophilized soybean leaves was performed using CCl4-n-heptane and ultracentrifugation that yielded a gradient comprised of six fractions. Chlorophyll content, and marker enzyme activities, phosphoenolpyruvate carboxylase (PEPC) and α-mannosidase, were utilized as stroma, cytosol and vacuole markers, respectively. GC-MS analyses of each fraction resulted in the identification of around 100 different metabolites. The distribution of these identified compounds showed a decreasing order from the vacuole to cytosol to chloroplast stroma. In other words, a greater number of identified compounds were found in the vacuole when compared to the cytosol or stroma. Levels of sugars, organic acids and fatty acids showed greater relative abundances in the vacuole with 50, 55, and 50% of the respective pools. A greater relative abundance of amino acids was observed in the cytosol where 45% of the total of amino acids content was recorded. The relatively large pool of sugars and phenolic acids in the vacuole compartment implies high levels of starch metabolism and phenylpropanoid biosynthesis. The low amino acids pool, on the other hand, suggests low nitrogen accumulation in the leaves of soybean. Hierarchical cluster analysis on the most abundant metabolites revealed three clusters containing 10, 20, and 2 of the 32 selected metabolites. The data were discussed in term of NAQF and GC-MS analysis of soybean mature leaves, and also in term of distribution and compartmentation of metabolites at subcellular levels

Difference in Carbon Distribution of Initial Photoassimilates between Soybean and Rice as Revealed by 20 s Pulse-300 s Chase Experiments

Short pulse-chase labeling experiments indicated that there was a considerable difference between soybean and rice in the distribution pattern of 14C to major metabolites during a 300 s chase period. The distribution of 14C to starch at the end of the chase period was largest in soybean but very small in rice. In rice, the distribution of 14C to sucrose was the largest. Starch formation during the initial stages of photosynthesis implied the existence of a different mechanism of starch synthesis and utilization between soybean and rice. The relative intensity of the flow into starch increased by treatment with 2% O2, suggesting that photorespiratory pathway may involve in the regulation of higher starch accumulation in soybea

Metabolic alterations proposed by proteome in rice roots grown under low P and high Al concentration under low pH

Growth inhibition caused by acid soils, especially due to P deficiency and Al stress, is a serious problem for crop production. To comprehend the adaptation mechanisms of rice plants to P deficiency and Al stress conditions, a proteomic analysis of rice roots in hydroponic cultivation was demonstrated. Four hundred and sixty-four detectable proteins spots were separated by 2D-PAGE. Fifty-six of 94 spots selected at random were identified by peptide mass fingerprinting. In general, the proteomic alterations under P deficiency and Al stress conditions were similar trend, indicating that a common metabolic system is responsive to both P deficiency and Al stress. An increase in nucleotide monomer synthesis was indicated from the related proteomic alterations, which mediate the reversible reactions of the triose phosphate/pentose phosphate pool, and the oxidative reactions of the pentose phosphate pathway under both stress conditions. Carbon flow to the TCA cycle and N assimilation were altered in proteomic level. The changes could be contributed to the complementation of TCA components from suppression of photosynthates partitioning from leaves, and partly contribute to organic acid secretion. Induction of S-adenosylmethionine (SAM) synthetase is a significant and unique response to Al stress, suggesting that SAM is related to ethylene-mediated inhibition of root growth and/or the alteration of cell wall structures and polymers in roots

Application of ionomics to plant and soil in fields under long-term fertilizer trials

Ionomics is the study of elemental accumulation in living organisms using high-throughput elemental profiling. In the present study, we examined the ionomic responses to nutrient deficiency in maize grown in the field in long-term fertilizer trials. Furthermore, the available elements in the field soils were analyzed to investigate their changes under long-term fertilizer treatment and the ionomic relationships between plant and soil. Maize was cultivated in a field with the following five long-term fertilizer treatments: complete fertilization, fertilization without nitrogen, without phosphorus, without potassium, and no fertilization. Concentrations of 22 elements in leaves at an early flowering stage and in soils after harvest were determined. The fertilizer treatments changed the availabilities of many elements in soils. For example, available cesium was decreased by 39 % and increased by 126 % by fertilizations without nitrogen and potassium, respectively. Effects of treatments on the ionome in leaves were evaluated using the translocation ratio (the concentration in leaves relative to the available concentration in soils) for each element. Nitrogen deficiency specifically increased the uptake ability of molybdenum, which might induce the enhancement of nitrogen assimilation and/or endophytic nitrogen fixation in plant. Potassium deficiency drastically enhanced the uptake ability of various cationic elements. These elements might act as alternatives to K in osmoregulation and counterion of organic/inorganic anions. Two major groups of elements were detected by multivariate analyses of plant ionome. Elements in the same group may be linked more or less in uptake and/or translocation systems. No significant correlation between plant and soil was found in concentrations of many elements, even though various soil extraction methods were applied, implying that the interactions between the target and other elements in soil must be considered when analyzing mineral dynamics between plant and soil

The role of potassium on the remediation for the radiocesium contaminated soil

The Tokyo Electric Company's Fukushima Dai-ichi Nuclear Power Plant accident contaminated a large area of agricultural land with radioactive cesium. If the contamination levels were high, topsoil removal or inversion tillage were the major countermeasures used to decrease the radioactivity of the soil. However, a substantial level of radioactive cesium remained in the soil, even after decontamination and some fields weren't decontaminated. To mitigate radioactive cesium transfer from soil to plant, we tested increasing potassium levels in the soil. In this paper, we demonstrate how we developed these countermeasures in Fukushima