Body concentration of caesium-137 in patients from Western Isles of Scotland.

OBJECTIVES--To compare caesium-137 concentrations in patients from the Western Isles Health Board, Glasgow area, and other parts of the Scottish mainland, and to investigate the source of 137Cs in patients from the Western Isles. DESIGN--Study of hypertensive patients having electrolyte concentrations measured, including 137Cs. Interview by questionnaire of island subjects about intake of foods likely to contain radiocaesium and the source of these foods. Measurement of 137Cs and 134Cs in food, urine, and vegetation. SETTING--Scottish mainland and Western Isles, 1979-86. All measurements before Chernobyl nuclear accident. PATIENTS--413 consecutive patients referred to the blood pressure unit for investigation of hypertension. 60 from the Western Isles, including 44 from North Uist; 32 from North Uist participated in the dietary analysis. MAIN OUTCOME MEASURES--Concentration of radiocaesium in the body, urine, food, and vegetation. Islanders'' consumption of local produce. RESULTS--Patients from the Western Isles had five times higher body concentrations of 137Cs (median 2.54 (interquartile range 1.25-3.73)) Bq/gK) than did patients from around Glasgow (0.47 (0.26-0.66) Bq/gK) and other parts of the Scottish mainland (0.42 (0.24-0.71) Bq/gK). Islanders often consumed local milk and mutton, but ate local fish rarely. 137Cs and 134Cs were present in coastal (21.6 Bq/kg 137Cs, 0.25 Bq/kg 134Cs) and moorland (135.9, 0.65 Bq/kg) grasses and in islanders'' urine (2.01, 0.013 Bq/l). Lower concentrations (0.336, 0.004 Bq/l), were found in the urine of Glasgow controls (p less than 0.001 for both isotopes). CONCLUSIONS--Islanders have excess body 137Cs concentrations, most of which probably comes from local milk and lamb. The radioactivity is not above the recommended safety limit. The presence of 134Cs suggests that nuclear reprocessing is the source of some of the radiocaesium.     

Effects of low chronic doses of ionizing radiation on antioxidant enzymes and G6PDH activities in Stipa capillata (Poaceae)

Stipa capillata (Poaceae) seeds were harvested from a control area (displaying a gamma dose rate of 0.23 micro Sv h(-1)) (C plants) and from two contaminated areas (5.4 and 25 micro Sv h(-1)) on the Semipalatinsk nuclear test site (SNTS) in Kazakhstan. The plants were grown for 124 d in a greenhouse under controlled conditions and exposed to three different treatments: (0) control; (E) external gamma irradiation delivered by a sealed 137Cs source with a dose rate of 66 micro Sv h(-1); (E+I) E treatment combined with internal beta irradiation due to contamination by 134Cs and 85Sr via root uptake from the soil. The root uptake led to a contamination of 100 Bq g(-1) for 85Sr and 5 Bq g(-1) for 134Cs (of plant dry weight) as measured at harvest. The activity of SOD, APX, GR, POD, CAT, G6PDH, and MDHAR enzymes was measured in leaves. Under (0) treatment, all enzymes showed similar activities, except POD, which had higher activity in plants originating from contaminated areas. Treatment (E) induced an enhancement of POD, CAT, GR, SOD, and G6PDH activities in plants originating from contaminated areas. Only control plants showed any stimulation of APX activity. Treatment (E+I) had no significant effect on APX, GR, CAT, and POD activities, but MDHAR activity was significantly reduced while SOD and G6PDH activities were significantly increased. The increase occurred in plants from all origins for SOD, with a greater magnitude as a function of their origin, and it occurred only in plants from the more contaminated populations for G6PDH. This suggests that exposure to a low dose rate of ionizing radiation for almost a half century in the original environment of Stipa has led to natural selection of the most adapted genotypes characterized by an efficient induction of anti-oxidant enzyme activities, especially SOD and G6PDH, involved in plant protection against reactive oxygen species.     

Identification and expression studies of a catalase and a bifunctional catalase-peroxidase in Frankia strain R43

This study investigated the uptake of ¹³⁴Cs by Lactuca sativaL., Silybum marianumGaertn., Centaurea cyanusL., Carthamus tinctorius L. from the Asteraceae, and Beta vulgaris L. var. `Lutiancai' and Beta vulgaris L. var. `Hongtiancai' from the Chenopodiaceae grown in two widely-distributed soils (a paddy soil and a red soil) in South China. The results showed that the plants growing on the paddy soil had a relatively high yield and low [¹³⁴Cs] while those growing on the red soil showed the opposite trend. The accumulation of ¹³⁴Cs was dependent on plant species and soil types. For the paddy soil, mean values for [¹³⁴Cs] were higher for the species of the Asteraceae (ranging from 165 to 185 Bq g^–1) than for those of the Chenopodiaceae (less than 140 Bq g^–1). For the red soil, S. marianumand C. cyanus of the Asteraceae had high average concentrations of ¹³⁴Cs ranging from 340 to 400 Bq g^–1 but L. sativa and C. tinctorius from the same family had low concentrations of ¹³⁴Cs ranging from 115 to 200 Bq g^–1 on a dry weight basis. B. vulgaris L. var. `Lutiancai' and Beta vulgaris L. var. `Hongtiancai' accumulated from 120 to 231 Bq ¹³⁴Cs g^–1 of plant shoot. The transfer factor values of ¹³⁴Cs for the studied species were in general higher in red soil than in paddy soil except C. tinctorius. All plant species from the Asteraceae family growing on the paddy soil had higher transfer factors than the B. vulgaris species. S. marianum, and C. cyanus growing on the red soil had TFs >1, being much higher than the B. vulgaris species. The results therefore showed that the plant species from the Asteraceae could accumulate higher concentrations of radiocesium than the Beta vulgaristhat has previously been suggested as a candidate for phytoremediation of radiocesium contaminated soils.     

Identification of putative parasitism genes expressed in the esophageal gland cells of the soybean cyst nematode Heterodera glycines

Cloning parasitism genes encoding secretory proteins expressed in the esophageal gland cells is the key to understanding the molecular basis of nematode parasitism of plants. Suppression subtractive hybridization (SSH) with the microaspirated contents from Heterodera glycines esophageal gland cells and intestinal region was used to isolate genes expressed preferentially in the gland cells of parasitic stages. Twenty-three unique cDNA sequences from a SSH cDNA library were identified and hybridized to the genomic DNA of H. glycines in Southern blots. Full-length cDNAs of 21 clones were obtained by screening a gland-cell long-distance polymerase chain reaction cDNA library. Deduced proteins of 10 clones were preceded by a signal peptide for secretion, and PSORT II computer analysis predicted eight proteins as extracellular, one as nuclear, and one as plasmalemma localized. In situ hybridization showed that four of the predicted extracellular clones were expressed specifically in the dorsal gland cell, one in the subventral gland cells, and three in the intestine in H. glycines. The predicted nuclear clone and the plasmalemma-localized clone were expressed in the subventral gland cells and the dorsal gland cell, respectively. SSH is an efficient method for cloning putative parasitism genes encoding esophageal gland cell secretory proteins that may have a role in H. glycines parasitism of soybean.     

134Cs and 137Cs levels in a grassland, 32 km northwest of the Fukushima 1 Nuclear Power Plant, measured for two seasons after the fallout

We measured the levels of radioactive caesium (RACs; ¹³⁴Cs and ¹³⁷Cs) in plants and soil in a grassland, 32 km northwest of the Fukushima 1 Nuclear Power Plant, from June 2011 to October 2012. In 2011, the highest RACs levels (¹³⁴Cs + ¹³⁷Cs) in plants and in the 0–5 cm soil layer were approximately 80 kBq per kg dry weight (DW). Forage grasses and clovers in this grassland showed similar RACs levels. On a DW basis, the levels of RACs in these plants tended to increase with increasing biomass over both years, but the absolute levels decreased in 2012. The RACs levels in the soil decreased sharply with soil depth; the RACs level in the 5–10 cm soil layer was only 3 % of that in the 0–5 cm layer. The transfer factor (ratio of radioactivity in plant parts on DW basis to that in the 0–10 cm soil layer) was 0.5 and 1.0 for the aboveground and belowground plant parts, respectively, in 2011, and these values decreased by approximately 50 % in 2012. We discuss the possible mechanisms underlying these trends, and strategies to decrease the level of RACs in plants to the permissible level for forage.     

Fallout radiocesium in an Antarctic region:

To improve the knowledge about the (137)Cs spatial distribution and vertical migration in soils of the Southern Hemisphere, the total areal activity density and the vertical transport parameters of this radionuclide were measured in an Antarctic region. For this purpose vegetation and incremental soil samples were collected at 21 representative sites located at 4 islands of the South Shetland Archipelago: King George, Robert, Greenwich and Snow (62-63 degrees S and 58-62 degrees W). The total (137)Cs activity density varied considerably from 118 to 662 Bq m(-2) (median 384 Bq m(-2), reference date 1995), with a high percentage of the total activity retained in the vegetation cover (5-98% in moss, 3-20% in lichen and 4-12% in grass). At most sites, the maximum activity density in soil was observed in the top layer from where it decreased continuously. To evaluate the transport parameters of (137)Cs from the activity-depth profiles, the classical convection-diffusion model was used based on the time-course of the annual deposition density of (137)Cs at the studied region. The values for the diffusion coefficient D(s) (median 0.043 cm(2) year(-1)) and the convection velocity v(s) (median -0.012 cm year(-1)) of radiocesium observed under a polar climate are small compared to the transport parameters determined in temperate zones. The data also indicate that at these sites the convectional transport of (137)Cs is almost negligible compared to the transport by diffusion. The high vulnerability of the Antarctic soils to (137)Cs deposition, as a consequence of its very slow transport due to the extreme climatic conditions at these latitudes, has been confirmed.     

Comparison of the post-Chernobyl 137Cs contamination of mushrooms from eastern Europe, Sweden, and North America.

A comparison was made of 134Cs and 137Cs contamination in fungi from eastern Europe and eastern North America. Mean activities of 25 Ukrainian, 6 Swedish, and 10 North American collections were 4,660, 9,750, and 205 Bq/kg (dry weight), respectively. Additional measurements were made on samples from the Moscow, southern Belarus, and Yugoslavia/Bulgaria regions. Activity values were found to vary by several orders of magnitude within all geographic areas, even for the same mushroom species. Significantly higher specific activities were observed in mycorrhizal species than in saprophytic and parasitic fungi. Unfortunately, many of the European mycorrhizal species considered as prized edibles contained unacceptably high levels of 137Cs (> 1,000 Bq/kg [dry weight]) and should be used sparingly as food. By contrast, no mushrooms collected in Ontario or northern Michigan exceeded 1,000 Bq of 137Cs per kg (dry weight). The excessive 137Cs contamination was evident in mushrooms from areas that had substantial fallout from the 1986 accident in reactor 4 at the Chernobyl nuclear power station. However, observations suggest that about 20% of the 137Cs in eastern Europe (Moscow area, Belarus, and Ukraine) is of non-Chernobyl origin.     

Fate of radiocesium in freshwater aquatic plants and algae in the vicinity of the Fukushima Daiichi nuclear power plant

The behavior of radiocesium (¹³⁷Cs) in aquatic plants (five species) and algae (three genera) grown in either a river (one sampling point) or pond (four sampling points) in the vicinity of the Fukushima Daiichi nuclear power plant was investigated. The ¹³⁷Cs concentration of <0.45-μm fractions of water taken from the river and ponds was between 5.01 × 10^?1 and 2.98 Bq/L, while that of sediment was between 4.85 × 10³ and 5.72 × 10⁴ Bq/kg dry weight. The ratio of ¹³⁷Cs concentration of sediment/water in ponds was ~10⁴. The sediment-to-plant transfer factor (TF) [(¹³⁷Cs concentration Bq/kg dry weight_plant) × (¹³⁷Cs concentration Bq/kg dry weight_sediment)^?1] was also measured. For aquatic plants, the highest value was 5.55 for Potamogeton crispus from the river, while the lowest was 3.34 × 10^?2 for P. distinctus from a pond. There were significant differences in values between aquatic plants belonging to the same genus. The water-to-plant TF [(¹³⁷Cs concentration Bq/kg dry weight_plant) × (¹³⁷Cs concentration Bq/L_water)^?1] of filamentous algae (Spirogyra sp.) and cyanobacteria (coexisting Anabaena sp. and Microcystis sp.) were 2.39 × 10³ and 1.26 × 10³, respectively. The ¹³⁷Cs concentration of cyanobacteria in pond water was 4.87 × 10^?1 Bq/L, which was the same order of magnitude as the ¹³⁷Cs concentration of pond water. Enrichment of ¹³⁷Cs in cyanobacteria was not observed.     

Effect of biotite,zeolite, heavy clay,bentonite and apatite on the uptake of radiocesium by grass from peat soil

Biotite is a potassium rich mineral, which is used as a fertilizer in organic farming and as a soil amendment in conventional farming. Its ability to reduce ¹³⁴Cs uptake by ryegrass from peat soil was studied in pot experiments and compared with zeolite, heavy clay, bentonite and apatite. In addition, the long-term effect of biotite on ¹³⁷Cs uptake from peat soil was studied in the peat field. In the pot experiments in the first cut of ryegrass, the minerals decreased ¹³⁴Cs uptake by plants in the following order: zeolite > heavy clay > bentonite > biotite > apatite. Apatite did not have any effect on the plant ¹³⁴Cs level. In the later cuts, the uptake of ¹³⁴Cs from biotite-treated soil decreased further while that from soils treated with other minerals remained unchanged or even increased. In general, ¹³⁴Cs uptake by plants decreased with increasing mineral level. The decrease of ¹³⁴Cs uptake became more efficient, especially at the early growth stage, by mixing small amounts of zeolite in biotite. The results of the field experiment indicated the long-term effect of biotite on reducing ¹³⁴Cs uptake by plants. Biotite application rate was 30 t ha-1. The five-year mean of the plant/soil concentration ratio of ¹³⁷Cs was 0.05 for biotite-treated soil, in contrast to 0.14 for the control soil. On the whole, biotite reduced considerably the ¹³⁷Cs level of plants on peat soil and this effect was long-lasting. For an effective reduction of plant radiocesium a great quantity of biotite is needed and therefore it is most suitable for greenhouse cultivation where contaminated slightly decomposed peat is used as a growing medium.     

Verification of radiocesium decontamination from farmlands by plants in Fukushima

The purpose of this study was to verify radiocesium decontamination from Fukushima farmland by plants and to screen plants useful for phytoremediation. Thirteen species from three families (Asteraceae, Fabaceae, and Poaceae) of crops were grown in shallow and deeply cultivated fields (0–8 and 0–15 cm plowing, respectively). To change plowing depth was expected to make different contacting zone between root system and radiocesium in soil. The radioactivity values of the plants due to the radiocesium ¹³⁴Cs and ¹³⁷Cs were 22–179 and 29–225 Bq kg dry weight^?1, respectively. The ¹³⁴Cs and ¹³⁷Cs transfer factors for plants grown in the shallow field ranged from 0.021 to 0.12 and fro 0.019 to 0.13, respectively, with the geometric means of 0.051 and 0.057, respectively. The ¹³⁴Cs and ¹³⁷Cs transfer factors for plants grown in the deep field ranged from 0.019 to 0.13 and from 0.022 to 0.13, respectively, with the geometric means of 0.045 and 0.063, respectively. Although a reducing ratio was calculated to evaluate the decrease in radiocesium from contaminated soil during cultivation (i.e., phytoremediation ability), no plant species resulted in a remarkable decrease in radiocesium in soil among the tested crops. These results should be followed up for several years and further analyses are required to evaluate whether the phytoremediation technique is applicable to radioactively contaminated farmlands.     

Radioecological research of the Irtysh-River's and Ob-River's water, base and flood depositions

The radioecological research of Irtysh-river and Ob-river was held. The content of 137Cs in Irtysh water was compounded 0.62-1.23 Bq/m3, in Ob-- 0.24-0.27 Bq/m3, and the one of 90Sr in Irtysh-- 10-20 Bq/m3, and in Ob-- 5-10 Bq/m3, that is much lower than the permissible sanitary-hygienic norms for the population. The 137Cs stores density on Irtysh-river input lease was compounded 2.7 kBq/m2, is almost in 11 times slashed downstream and is peer 245 kBq/m2 before the Irtysh-river lockin. The 90Sr stores density also was slashed in surveyed leases with 212 down to 106 Bq/m2. Two variants of integrated stores of 137Cs and of 90Sr in flood of the Irtysh-river was held. The balance calculation of annual radionuclides sinks confirms the dominant amount of 137Cs and of 90Sr in downstream Ob-river leases acts now on the Ob's sleeve, instead of from the Irtysh-river as it was supposed earlier. The 137Cs medial annual inflow from the Ob's sleeve almost is in 2 times, and the 90Sr inflow is in 2.3 times more, than are acts from Irtysh-river sleeve.     

Cesium toxicity in Arabidopsis

Cesium (Cs) is chemically similar to potassium (K). However, although K is an essential element, Cs is toxic to plants. Two contrasting hypotheses to explain Cs toxicity have been proposed: (1) extracellular Cs+ prevents K+ uptake and, thereby, induces K starvation; and (2) intracellular Cs+ interacts with vital K(+)-binding sites in proteins, either competitively or noncompetitively, impairing their activities. We tested these hypotheses with Arabidopsis (Arabidopsis thaliana). Increasing the Cs concentration in the agar ([Cs](agar)) on which Arabidopsis were grown reduced shoot growth. Increasing the K concentration in the agar ([K](agar)) increased the [Cs](agar) at which Cs toxicity was observed. However, although increasing [Cs](agar) reduced shoot K concentration ([K](shoot)), the decrease in shoot growth appeared unrelated to [K](shoot) per se. Furthermore, the changes in gene expression in Cs-intoxicated plants differed from those of K-starved plants, suggesting that Cs intoxication was not perceived genetically solely as K starvation. In addition to reducing [K](shoot), increasing [Cs](agar) also increased shoot Cs concentration ([Cs](shoot)), but shoot growth appeared unrelated to [Cs](shoot) per se. The relationship between shoot growth and [Cs](shoot)/[K](shoot) suggested that, at a nontoxic [Cs](shoot), growth was determined by [K](shoot) but that the growth of Cs-intoxicated plants was related to the [Cs](shoot)/[K](shoot) quotient. This is consistent with Cs intoxication resulting from competition between K+ and Cs+ for K(+)-binding sites on essential proteins.     

The slingshot family of phosphatases mediates Rac1 regulation of cofilin phosphorylation, laminin-332 organization, and motility behavior of keratinocytes

The motility of keratinocytes is an essential component of wound closure and the development of epidermal tumors. In vitro, the specific motile behavior of keratinocytes is dictated by the assembly of laminin-332 tracks, a process that is dependent upon alpha6beta4 integrin signaling to Rac1 and the actin-severing protein cofilin. Here we have analyzed how cofilin phosphorylation is regulated by phosphatases (slingshot (SSH) or chronophin (CIN)) downstream of signaling by alpha6beta4 integrin/Rac1 in human keratinocytes. Keratinocytes express all members of the SSH family (SSH1, SSH2, and SSH3) and CIN. However, expression of phosphatase-dead versions of all three SSH proteins, but not dominant inactive CIN, results in phosphorylation/inactivation of cofilin, changes in actin cytoskeleton organization, loss of cell polarity, and assembly of aberrant arrays of laminin-332 in human keratinocytes. SSH activity is regulated by 14-3-3 protein binding, and intriguingly, 14-3-3/alpha6beta4 integrin protein interaction is required for keratinocyte migration. We wondered whether 14-3-3 proteins function as regulators of Rac1-mediated keratinocyte migration patterns. In support of this hypothesis, inhibition of Rac1 results in an increase in 14-3-3 protein association with SSH. Thus, we propose a novel mechanism in which alpha6beta4 integrin signaling via Rac1, 14-3-3 proteins, and SSH family members regulates cofilin activation, cell polarity, and matrix assembly, leading to specific epidermal cell migration behavior.     

Identification of Genes Differentially Expressed by <Emphasis Type="Italic">Metarhizium anisopliae</Emphasis> Growing on <Emphasis Type="Italic">Locusta migratoria</Emphasis> Wings Using Suppression Subtractive Hybridization

Insect-pathogenic fungi penetrate their hosts directly through the cuticle. To better understand this process, we identified genes that were up-regulated by Metarhizium anisopliae germinating and differentiating on Locusta migratoria wings using suppression subtractive hybridization (SSH). A total of 78 unique expressed sequence tags (ESTs) up-regulated more than twofold during fungal growth on locust wings were identified. Among these 78 ESTs, 30 (38.5%) shared significant similarity with NCBI annotated hypothetical proteins, 16 (20.5%) shared low similarity to known or predicted genes, might represent novel genes, and 32 (41.0%) shared significant similarity with known proteins that are involved in various cell and molecular processes such as cell metabolism, protein metabolism, stress response and defense, and cell structure and function. Semi-quantitative RT-PCR analysis of six randomly selected genes confirmed the SSH results, verifying the fidelity of the SSH data. The results of this study provide novel information on genes expressed during early stages of infection with M. anisopliae, and improve current understanding of fungal pathogenesis.     

Concentration of Radiocesium in the Wild Japanese Monkey (Macaca fuscata) over the First 15 Months after the Fukushima Daiichi Nuclear Disaster

Following the massive earthquake that struck eastern Japan on March 11, 2011, a nuclear reactor core meltdown occurred at the Fukushima Daiichi Nuclear Power Plant, operated by Tokyo Electric Power Company, and was followed by the release of large amounts of radioactive materials. The objective of this study was to measure the concentration of radiocesium ¹³⁴Cs and ¹³⁷Cs in the muscle of Japanese monkeys (Macaca fuscata) inhabiting the forest area of Fukushima City and to determine the change in concentration over time as well as the relationship with the level of soil contamination. Cesium concentrations in the muscle of monkeys captured at locations with 100,000–300,000 Bq/m² were 6,000–25,000 Bq/kg in April 2011 and decreased over 3 months to around 1,000 Bq/kg. However, the concentration increased again to 2,000–3,000 Bq/kg in some animals during and after December 2011 before returning to 1,000 Bq/kg in April 2012, after which it remained relatively constant. This pattern of change in muscle radiocesium concentration was similar to that of the change in radiocesium concentration in atmospheric fallout. Moreover, the monkeys feed on winter buds and the cambium layer of tree bark potentially containing higher concentrations of radiocesium than that in the diet during the rest of the year. The muscle radiocesium concentration in the monkeys related significantly with the level of soil contamination at the capture locations.     

Soil-to-grain transfer of fallout <Superscript>137</Superscript>Cs for 28 winter wheat cultivars as observed in field experiments

In order to find wheat cultivars with a minimum soil-to-grain transfer of fallout (137)Cs, 28 winter wheat cultivars were investigated at 3 different sites with different soil types in Bavaria, Germany. Each cultivar was grown on an area of 10 m(2) and harvested in August 1999. The soil-to-grain concentration ratios (C(r)) of (137)Cs varied by a factor of up to 3 from cultivar to cultivar at a given site and from site-to-site for a given cultivar. The mean C(r) values at the three sites, 4.2 x 10(-4), 4.9 x 10(-4) and 7.5 x 10(-4), differed significantly. The fact that no cultivar showed similar C(r) values at the three sites indicates a strong influence of the soil on C(r). The cultivars Flair, Kornett and Previa showed a minor uptake of (137)Cs compared with the mean of all cultivars at each site. Unlike (137)Cs, the (40)K concentrations in the wheat grains varied only within a small range (122-190 Bq kg(-1)) at each site, which is due to the potassium regulation by the plants. For both radionuclides, the differences between the root uptake characteristics of the cultivars may not only be explained by an inter-cultivar variability due to genetic differences between the cultivars, but also by an intra-cultivar variability due to different soil conditions.