Reduction of Radiocesium in Internal- and Surface-Contaminated Komatsuna (Brassica rapa var. perviridis) during Washing and Processing.

Radiocesium dynamics data during food processing are required for the realistic estimation of internal radiation content in food. Radiocesium contamination of leafy vegetables can occur externally due to the adhesion of fallout and/or resuspension from the air, and internally from soil via the root transport. Information regarding the dynamics of both surface and internal radiocesium contamination during food processing is required; however, such information for leafy vegetables is limited compared to other major agricultural products. In this study, the effect of washing on the removal of surface radiocesium contamination by resuspended materials and that of cooking (grilling, boiling, and microwave heating) on internal radiocesium contamination were investigated using komatsuna (Brassica rapa var. perviridis), a leafy vegetable. The surface-contaminated samples were experimentally grown in a difficult-to-return area in Fukushima Prefecture, which has not yet been decontaminated. The internally contaminated komatsuna were obtained after experimental cultivation in a greenhouse with soil containing 137Cs and no surface contamination. The concentration of 137Cs in surface-contaminated komatsuna was reduced to approximately half (processing factor: 0.55) after washing with water. However, the annual processing factor ranged from 0.12 to 0.95, suggesting that the growing environment and climatic conditions may affect the removal rate of radiocesium by washing. Internal contamination of 137Cs was removed by 23% and 14% by boiling and grilling, respectively, but no effect was observed for microwaving. Moreover, the concentration of 137Cs decreased by 0.66-fold after boiling, while it increased by 1.19- and 1.20-fold after grilling and microwaving, respectively. Therefore, boiling was found to be preferable than grilling or microwaving for radiocesium removal.

Applicability of non-destructive equipment for radioactivity measurement to screening radio-cesium in foods.

This study aimed to evaluate the applicability of non-destructive radioactivity measurement equipments for screening radio-cesium in whole foods without sample preparation procedures. Wild mushrooms and bamboo shoots were collected and studied using five different non-destructive radioactivity devices, and activity concentration was determined by conventional gamma-ray spectrometry using a Ge-detector. Linear regression analyses of activity concentrations were conducted and prediction intervals determined as uncertainties. Overall, non-destructive radioactivity measurement devices found to be suitable for screening radioactive cesium contamination in foods with an effective screening level.

Distribution of Radioactive Cesium during Wild Boar Meat Processing.

ABSTRACT: Wild boar meat containing radioactive cesium (Cs) of approximately 1,000 Bq/kg (134Cs+137Cs) was processed into bacon, sausage, and ham. To understand the concentration and quantity change of radioactive Cs, the processing factor (Pf) and food processing retention factor (Fr) were calculated. The radioactive Cs quantity in the meat did not reduce during smoking. The dehydration-related meat mass reduction during smoking without decrease of radioactive Cs led to Cs condensation in the bacon compared with the raw rib meat before processing, resulting in a Pf of 1.18. Soaking in liquid, such as pickling in liquid and desalting or boiling in water, effectively removed radioactive Cs by leakage into water. Therefore, the Fr value of the boiled ham produced from a loin meat block through three liquid-soaking processes was 0.27. The Pf value of the boiled ham was 0.30 due to meat block mass reduction after boiling as a result of dehydration, along with protein thermal denaturation-related muscle tissue shrinkage. The steamed ham Fr value was 0.53, because the removal of radioactive Cs was less efficient by steaming than by boiling. The Pf value of the steamed ham was 0.54, almost the same as the Fr value, because the mass decrease rate was the same as the radioactive Cs decrease rate by steaming. The Fr and the Pf values of the boiled sausage, whose processing did not include soaking in the pickling liquid, were 0.64 and 0.62, respectively. Steaming the sausage meat did not remove radioactive Cs during the dehydration-related mass reduction, leading to Fr and Pf values of 1.01 and 1.17, respectively. This study found that processing into boiled ham was the most effective measure for reducing radioactive Cs quantity and concentration in raw meat. Processing into bacon and steamed sausage showed no Cs quantity reduction, with the moisture loss resulting in Cs condensation compared with the raw material.

Elution of Radioactive Cesium from Tofu by Water Soaking.

Elution of cesium-137 (137Cs) from tofu into water was investigated to know the behavior of 137Cs during preservation and cooking. The food processing retention factor (Fr) reached 0.55 when tofu was soaked in water at a ratio of 1:2 w/w for 24 h at 4°C. Doubling the amount of water did not further significantly decrease Fr. When tofu was held in water at a ration of 1:2 w/w at a temperature of 80℃ for 50 min, Fr was 0.72. Increasing the amount of water to 10 times the tofu weight did not further reduce Fr significantly. Cesium-137 is mostly bound to tofu and does not freely diffuse into water. Tofu was then soaked in water at a ratio of 1:2 w/w at 4℃ for 24 h, placed in new water at a ratio of 1:2 w/w, and held at 80℃ for 50 min, resulting in an Fr 0.33. This value is close to an estimated Fr calculated by multiplying the Fr of 0.55 from soaking at 4°C by the Fr of 0.72 from the hot water treatment. The calculated Fr from soybeans sequentially processing into tofu, soaking tofu at 4°C for 24 h and in hot water at 80°C for 50 min was about 0.1, indicating 90% removal of 137Cs. Degree of decrease in 137Cs during preservation and cooking of tofu demonstrated in this study will be useful for exposure assessment of 137Cs through oral intake of contaminated soybeans after processing and cooking.

Relationships between air dose rates and radionuclide concentrations in agricultural plants observed in areas affected by the Fukushima Dai-ichi accident.

Most of environmental monitoring programs include measurements of the air dose rates and the radionuclides activity concentration in plants. Both these parameters depend on deposition density of radionuclides. Therefore, measurements of one parameter can (with some supplementary information) be used as an indicator for the other parameter. After the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, the Emergency Operation Centre (EOC) operated by the Environmental Radioactivity Monitoring centre of Fukushima and Ministry of Agriculture, Forestry and Fisheries (MAFF) of Japan carried out large sampling programme over different distances from the NPP. The sampling programme was focused on the usage of the weed leaves as a proxy for the prediction of radionuclide transfer to some cultivated plants. The MAFF monitoring programme in 2011-2016 was addressed mainly to agricultural crops. In both cases, the air dose rates were measured at the sites of the sampling. The paper addresses the assessments of relationship between radionuclide activities concentrations in plants and ambient dose rates. The time-dependent relationships were quantified based on weed, buckwheat, brown rice and soybean data obtained in 2011-2016. The recommendations on optimizing emergency sampling programmes based on use of the data of ambient dose rates are also presented.

Large-scale agricultural soil and food sampling and radioactivity analysis during nuclear emergencies in Japan: Development of technical and organisational procedures for soil and food sampling after the accident.

Most available measurement methods and protocols for radioactive materials are focused on the use of high-precision sampling and analysis and do not consider the practicality of these techniques in the case of large-scale emergencies involving high numbers of samples and measurements. The experience gained after the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident has demonstrated a need for optimization of sampling and measurement programmes in the case of nuclear emergency that affects food and agriculture. Under these conditions, resources for implementation of monitoring and allocations for sampling and measurements might be limited, and urgent information is needed for effective emergency response. This paper supplies a historical overview of sampling and analytical techniques for assessment of radionuclides in the agricultural environments and foodstuffs and is intended for use in research, policy and decision-making in nuclear emergency preparedness and response, particularly with respect to large scale accidents.

Evaluation of 137Cs ageing by dynamics of 137Cs/133Cs ratio in Andosol paddy fields with/without potassium fertilizer application.

The mobility of 137Cs in soil decreases with time owing to fixation by micaceous minerals. Such ageing is a critical parameter for estimating and predicting annual change in 137Cs contamination risk of agricultural products. The decrease in the exchangeable fraction of 137Cs has traditionally been used as an index of the 137Cs ageing. Under field conditions, however, exchangeable 137Cs is influenced by several environmental factors. In this study, we propose a new index to evaluate the 137Cs ageing with minimum influence of environmental factors. The ratio of the exchangeable 137Cs fraction to exchangeable fraction of 133Cs ((137Cs/133Cs)exch) eliminates the influence of environmental factors on exchangeable 137Cs. We assessed the applicability of the (137Cs/133Cs)exch index, using a four-year field study of a rice paddy in allophanic Andosol, starting 200 days after the Fukushima Dai-ichi Nuclear Power Plant accident. The influence of K fertilization was also investigated. The 137Cs and 133Cs exchangeable fractions varied together, indicating that both were similarly controlled by environmental factors. The values of (137Cs/133Cs)exch decreased with time, reflecting 137Cs fixation by the ageing. The half-time of the (137Cs/133Cs)exch decline was 6.6-17.7 years. Relative to K fertilization, the lack of K fertilization seemed to affect the 137Cs ageing in two ways: the early 137Cs fixation progressed more rapidly, probably because fewer competing K+ ions were present, and the long-term ageing process was occasionally hampered, probably by the release of reserve K from micaceous minerals. The (137Cs/133Cs)exch values were similar to the ratio of the 137Cs to 133Cs transfer factor of the rice straw. Thus, we conclude that the (137Cs/133Cs)exch index is reliable for evaluating the 137Cs ageing, decrease in 137Cs mobility caused by the diffusion into micaceous mineral interlayer, in the field.

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.

Reduction in the Radiocesium in Meats of the Sika Deer and Wild Boar by Cooking.

ABSTRACT: The behavior of radiocesium in wild animal meats upon cooking was investigated. The ratio of the concentration change (processing factor, Pf), remaining ratio (food processing retention factor, Fr), and removal ratio of radiocesium in the meats by grilling, boiling, and steaming were determined. Differences in cooking methods, rather than differences in meat parts or animal species, clearly influenced the Pf, Fr, and removal ratios. The mean Fr values were 0.9 (range, 0.7 to 1.0) for grilling, 0.6 (range, 0.4 to 0.7) for boiling, and 0.5 (range, 0.4 to 0.7) for steaming. The removal effect of grilling (11%) was lower than that of boiling (41%) or steaming (47%). The mean value of Pf was 1.2 (range, 1.1 to 1.6) for grilling, 0.8 (range, 0.6 to 0.9) for boiling, and 0.8 (range, 0.7 to 1.0) for steaming. The radiocesium concentration in the meats increased only upon grilling, but not by boiling or steaming. This difference is due to the lower removal effect of grilling than that of boiling and steaming. Therefore, boiling and steaming were more effective than grilling for removing radiocesium and reducing its concentration in wild animal meats. Furthermore, the ratio of water content fluctuations due to boiling was negatively correlated with Pf and Fr. It was evident that greater reductions in water content resulted in lower concentrations and improved radiocesium removal in the meats. These results suggest that some of the radiocesium naturally present in the meats is soluble in water and that the radiocesium dissolved in water can be removed from the meat with the release of water from the tissue.

PERFORMANCE EVALUATION OF THE EQUIPMENT FOR MEASURING RADIOACTIVITY IN WHOLE FOODSTUFFS WITHOUT DESTRUCTIVE SAMPLE PREPARATION DEVELOPED AFTER THE FUKUSHIMA NPP ACCIDENT.

Recently, several types of instruments for measuring radioactivity in whole foodstuff were developed by manufacturers, in which any sample preparation technique such as machining was avoided, and such types of instruments are employed by agricultural producers or municipality radioactivity testing stations in Fukushima. In this study, radioactivity in various kinds of 91 samples collected by residents were measured by use of instruments for radioactivity measurement in whole samples, and the activity in each sample was also measured by use of the conventional gamma-ray spectrometry technique using calibrated Ge detectors after the sample machining procedure. The results obtained by instruments for measurement in whole samples were roughly proportional to the result obtained by a conventional technique, although large differences or unexpected variations were found in some specimens.

Distribution of Radioactive Cesium during Milling and Cooking of Contaminated Buckwheat.

To clarify the behavior of radioactive cesium (Cs) in buckwheat grains during milling and cooking processes, parameters such as processing factor (Pf) and food processing retention factor (Fr) were evaluated in two lots of buckwheat grains, R1 and R2, with different concentrations of radioactive Cs. Three milling fractions, the husk, bran, and flour fractions, were obtained using a mill and electric sieve. The radioactive Cs (134Cs + 137Cs) concentrations in husk and bran were higher than that in grain, whereas the concentration in flour was lower than that in grain. Pf values for the flours of R1 and R2 were 0.60 and 0.80, respectively. Fr values for the flours of R1 and R2 were 0.28 and 0.53, respectively. Raw buckwheat noodles (soba) were prepared using a mixture of buckwheat flour and wheat flour according to the typical recipe and were cooked with boiling water for 0.5, 1, and 2 min, followed by rinsing with water. Pf values for the soba boiled for 2 min (optimal for eating) made with R1 and R2 were 0.34 and 0.40, respectively. Fr values for these R1 and R2 samples were 0.55 and 0.66, respectively. Pf and Fr values for soba boiled for different times for both R1 and R2 were less than 0.6 and 0.8, respectively. Thus, buckwheat flour and its product, soba, cooked by boiling, are considered acceptable for human consumption according to the standard limit for radioactive Cs in buckwheat grains.

Influence of water management and fertilizer application on (137)Cs and (133)Cs uptake in paddy rice fields.

Cesium-137 derived from the Tokyo Electric Power Company's Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident contaminated large areas of agricultural land in Eastern Japan. Previous studies before the accident have indicated that flooding enhances radiocesium uptake in rice fields. We investigated the influence of water management in combination with fertilizers on (137)Cs concentrations in rice plants at two fields in southern Ibaraki Prefecture. Stable Cs ((133)Cs) in the plants was also determined as an analogue for predicting (137)Cs behavior after long-term aging of soil (137)Cs. The experimental periods comprised 3 y starting from 2012 in one field, and 2 y from 2013 in another field. These fields were divided into three water management sections: a long-flooding section without midsummer drainage, and medial-flooding, and short-flooding sections with one- or two-week midsummer drainage and earlier end of flooding than the long-flooding section. Six or four types of fertilizer subsections (most differing only in potassium application) were nested in each water management section. Generally, the long-flooding treatment led to higher (137)Cs and (133)Cs concentrations in both straw and brown rice than medial- and short-flooding treatments, although there were some notable exceptions in the first experimental year at each site. Effects of differing potassium fertilizer treatments were cumulative; the effects on (137)Cs and (133)Cs concentrations in rice plants were not obvious in 2012 and 2013, but in 2014, these concentrations were highest where potassium fertilizer had been absent and lowest where basal dressings of K had been tripled. The relationship between (137)Cs and (133)Cs in rice plants was not correlative in the first experimental year at each site, but correlation became evident in the subsequent year(s). This study demonstrates a novel finding that omitting midsummer drainage and/or delaying drainage during the grain-filling period enhances uptake of both (137)Cs and (133)Cs.

Distribution of radioactive cesium ((134)Cs plus (137)Cs) in rice fractions during polishing and cooking.

We investigated the distribution of cesium-134 ((134)Cs) and cesium-137 ((137)Cs) during polishing and cooking of rice to obtain their processing factors (Pf) and food processing retention factors (Fr) to make the information available for an adequate understanding of radioactive Cs dynamics. Polishing brown rice resulted in a decreased radioactive Cs concentration of the polished rice, but the bran and germ (outer layers) exhibited higher concentrations than brown rice. The Pf values for 100% polished rice and outer layers ranged from 0.47 to 0.48 and 6.5 to 7.8, respectively. The Fr values for 100% polished rice and outer layers were 0.43 and 0.58 to 0.60, respectively. The distribution of radioactive Cs in polished rice and outer layers was estimated at approximately 40 and 60%, respectively. On the other hand, cooked rice showed significantly lower levels of radioactive Cs than polished rice, and transfer of radioactive Cs into wash water was observed. The Pf and Fr values for cooked rice were 0.28 and 0.65 to 0.66, respectively. From these results, we can calculate that if the radioactive Cs concentration in brown rice is 100 Bq/kg, the concentrations of Cs in polished rice and cooked rice will be 47 to 48 Bq/kg and 13 Bq/kg, respectively.

Characterization of brown rice as a certified reference material for Fukushima accident-related radioactivity measurements.

We developed a certified reference material of brown rice to measure radioactivity from the Fukushima Daiichi Nuclear Power Plant accident. The rice was planted in the spring of 2011, just after the Fukushima accident occurred, and it was harvested in the autumn of 2011. The certified value of radioactivity concentration in the rice was 33.6 Bq kg(-1) of Cs-134 and 51.8 Bq kg(-1) of Cs-137 on August 1, 2012. The reference material is being widely distributed by the National Metrology Institute of Japan. To determine the radioactivity and its uncertainties in the brown rice, we employed gamma-ray spectrometry with a high-purity germanium detector and Monte Carlo simulation.

Distribution of radioactive cesium ((134)Cs Plus(137)Cs) in a contaminated Japanese soybean cultivar during the preparation of tofu, natto, and nimame (Boiled Soybean).

We investigated the fate of radioactive cesium ((134)Cs plus (137)Cs) during the production of tofu, natto, and nimame (boiled soybean) from a contaminated Japanese soybean cultivar harvested in FY2011. Tofu, natto, and nimame were made from soybean grains containing radioactive cesium (240 to 340 Bq/kg [dry weight]), and the radioactive cesium in the processed soybean foods and in by-product fractions such as okara, broth, and waste water was measured with a germanium semiconductor detector. The processing factor is the ratio of radioactive cesium concentration of a product before and after processing. For tofu, natto, nimame, and for the by-product okara, processing factors were 0.12, 0.40, 0.20, and 0.18, respectively; this suggested that these three soybean foods and okara, used mainly as an animal feed, can be considered safe for human and animal consumption according to the standard limit for radioactive cesium of soybean grains. Furthermore, the ratio of radioactive cesium concentrations in the cotyledon, hypocotyl, and seed coat portions of the soybean grain was found to be approximately 1:1:0.4.

A reduction in age-enhanced gluconeogenesis extends lifespan.

The regulation of energy metabolism, such as calorie restriction (CR), is a major determinant of cellular longevity. Although augmented gluconeogenesis is known to occur in aged yeast cells, the role of enhanced gluconeogenesis in aged cells remains undefined. Here, we show that age-enhanced gluconeogenesis is suppressed by the deletion of the tdh2 gene, which encodes glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a protein that is involved in both glycolysis and gluconeogenesis in yeast cells. The deletion of TDH2 restores the chronological lifespan of cells with deletions of both the HST3 and HST4 genes, which encode yeast sirtuins, and represses the activation of gluconeogenesis. Furthermore, the tdh2 gene deletion can extend the replicative lifespan in a CR pathway-dependent manner. These findings demonstrate that the repression of enhanced gluconeogenesis effectively extends the cellular lifespan.

Mutation of alpha-tubulin genes in trifluralin-resistant water foxtail (Alopecurus aequalis).

BACKGROUND: Trifluralin-resistant biotypes of water foxtail (Alopecurus aequalis) have been identified in wheat fields from northern Kyushu, Japan. Water foxtail is a winter-annual grassy weed, causing substantial crop losses. This study reports on mutation in α-tubulin (TUA) genes from water foxtail, the site of action of trifluralin. RESULTS: Two trifluralin-sensitive (S) Chikugo and Ukiha biotypes and four trifluralin-resistant (R) Asakura-1, Asakura-2, Tamana and Tosu biotypes of water foxtail were used for herbicide resistance analysis. R biotypes showed 5.7-30.7-fold trifluralin resistance compared with the S biotypes. No differences in the uptake and translocation of (14)C-trifluralin were observed between Chikugo (S) biotype and Asakura-1 (R) biotype. Most of the (14)C detected in the plant material was in the root tissue, and no substantial increases were noted in shoot tissues. Comparative TUA sequence analysis revealed two independent single amino acid changes: change of Val into Phe at position 202 in TUA1 and change of Leu into Met at position 125 in TUA3 in Asakura-1 biotype. In the Tamana (R) biotype, two amino acid changes of Leu to Phe at position 136 and Val to Phe at position 202 were observed in the predicted amino acid sequence of TUA1, compared with Chikugo (S) biotype. CONCLUSION: The results provide preliminary molecular explanation for the resistance of water foxtail to trifluralin, a phenomenon that has arisen as a result of repeated exposure to this class of herbicide. This is the first report of α-tubulin mutation in water foxtail and for any Alopecurus species reported in the literature.

Hst3 and Hst4 histone deacetylases regulate replicative lifespan by preventing genome instability in Saccharomyces cerevisiae.

The acetylation of histone H3 on lysine 56 (H3-K56) occurs during S phase and contributes to the processes of DNA damage repair and histone gene transcription. Hst3 and Hst4 have been implicated in the removal of histone H3-K56 acetylation in Saccharomyces cerevisiae. Here, we show that Hst3 and Hst4 regulate the replicative lifespan of S. cerevisiae mother cells. An hst3Δ hst4Δ double-mutant strain, in which acetylation of histone H3-K56 persists throughout the genome during the cell cycle, exhibits genomic instability, which is manifested by a loss of heterozygosity with cell aging. Furthermore, we show that in the absence of other proteins Hst3 and Hst4 can deacetylate nucleosomal histone H3-K56 in a nicotinamide adenine dinucleotide(NAD)(+) -dependent manner. Our results suggest that Hst3 and Hst4 regulate replicative lifespan through their ability to deacetylate histone H3-K56 to minimize genomic instability.

The inheritance of histone modifications depends upon the location in the chromosome in Saccharomyces cerevisiae.

Histone modifications are important epigenetic features of chromatin that must be replicated faithfully. However, the molecular mechanisms required to duplicate and maintain histone modification patterns in chromatin remain to be determined. Here, we show that the introduction of histone modifications into newly deposited nucleosomes depends upon their location in the chromosome. In Saccharomyces cerevisiae, newly deposited nucleosomes consisting of newly synthesized histone H3-H4 tetramers are distributed throughout the entire chromosome. Methylation of lysine 4 on histone H3 (H3-K4), a hallmark of euchromatin, is introduced into these newly deposited nucleosomes, regardless of whether the neighboring preexisting nucleosomes harbor the K4 mutation in histone H3. Furthermore, if the heterochromatin-binding protein Sir3 is unavailable during DNA replication, histone H3-K4 methylation is introduced onto newly deposited nucleosomes in telomeric heterochromatin. Thus, a conservative distribution model most accurately explains the inheritance of histone modifications because the location of histones within euchromatin or heterochromatin determines which histone modifications are introduced.

Cytosolic ascorbate peroxidase 2 (cAPX 2) is involved in the soybean response to flooding.

Proteomic analyses of soybean seedlings responding to flooding were conducted to identify key proteins involved. The seeds were germinated on a spongy matrix for two days, and then subjected to flooding for three days. After flooding, the total number of roots, the length of the main root, the lengths of the lateral and adventitious roots, and the fresh weight of the underground tissues of flooded soybean seedlings were significantly suppressed compared with nontreated plants. To identify the early flooding-responsive proteins, the seedling roots were used for preparing cytosolic and membrane fractions. After two-dimensional polyacrylamide gel electrophoresis and silver staining, 208 proteins were detected, and the levels of 44 were different from those of the control. The expression pattern of 10 proteins among the 44 from six different soybean cultivars confirmed that the 10 were flooding-responsive proteins. One of the 10 proteins was dominantly down-regulated under flooding conditions and was identified as cytosolic ascorbate peroxidase 2 (cAPX 2). Northern-hybridization showed that the abundance of cAPX 2 transcript decreased significantly after flooding, as did the enzymatic activity of APX. These results suggest that cAPX 2 is involved in flooding stress responses in young soybean seedlings.