Effect of low-dose chronic gamma exposure on growth and oxidative stress related responses in

The biological responses induced by low-dose chronic gamma exposure of hydroponically grown Arabidopsis thaliana, irradiated during a full life cycle (seed to seed) were investigated. Applied dose rates were 2300, 375 and 85 µGray h-1. Plants (roots and shoots) were harvested after 24 day (inflorescence emergence), at 34 days (∼50% of flowers open) and at 54 days (silice ripening). Gamma exposure significantly reduced root weight compared to the control but no clear effect of dose rate level on root dry weight was observed. Leaf weight was significantly reduced at the highest irradiation level, only after 54 days exposure. ED-10 was estimated at 10 µGy h-1. Seed germination was not affected by gamma irradiation. For several of the stress enzymes studied enzyme capacity was generally stimulated at the low and intermediate gamma irradiation level compared to the control and highest irradiation level. No pattern was observed in concentration or reduction state of the non-enzymatic antioxidants, ascorbate and glutathione. Lipid peroxidation products in leaves were present highest at full flowering and decreased with exposure level at this growth stage. At the other two growth stages, lipid peroxidation products were unaffected by gamma treatment

Monitoring cow comfort and rumen health indices in a cubicle-housed herd with an automatic milking system: a repeated measures approach (vol 68, 12, 2015)

[This corrects the article DOI: 10.1186/s13620-015-0040-7.]

On the nature and timing of oxygen radical production following exposure of

The toxicity and oxidative stress responses of 19-day old Arabidopsis seedlings induced by U (66 μM) and Cd (20 μM) alone or in a binary mixture set-up (equitoxic mixture) are studied in function of time. After 48h a significant decrease in root and shoot growth and a simultaneous increase in anthocyanin production was evident in all treated plants. Production of O−2 or H2O2 was visualized by staining freshly harvested leaves with nitrobluetetrazolium or diaminobezidine, respectively. With this method production of O−2 was only significantly measurable after 168 h treatment which coincides with a significant decrease in biomass production and probably also plant cell death. For Cd treated plants a significant increase in H2O2 production was measurable from 24h onwards. In contrast, a similar H2O2 production could not be measured in U or U + Cd treated plants. Both water and lipophilic soluble antioxidants significantly increased in U treated plants after 48 h. These high antioxidant levels might detoxify potential H2O2 produced in the U treated plants. In contrast for Cd treated plants only after 168h a significant increase in water soluble antioxidants was measured whereas no difference in the lipophilic fraction was visible

Study of biological effects and oxidative stress related responses in gamma irradiated

This study aimed at investigating biological effects in Arabidopsis thalianaleaves and roots irradiated for 72 h with 3.5 Gy or 30 Gy of gamma radiation, and to unravel oxidative stress related responses to achieve a better understanding of the importance of the cellular redox balance as a modulator in gamma radiation stress. A. thaliana performs like a rather radioresistant plant species as no alterations on growth and only minor alterations in the nutrient profile were observed. Gamma irradiation did not seem to induce an NADPH mediated oxidative burst and lipid peroxidation appeared to be directly induced by ionizing radiation rather than mediated through LOX activity. As ionizing radiation can cause indirect damage via water radiolysis, H2O2 is hypothesized to be an important reactive oxygen species under radiation stress. Although most H2O2-scavenging enzymes remained unchanged, important alterations were observed for CAT1, CAT2 and CAT3expression

Ecological characteristics influence farmer selection of on-farm plant density and bunch mass of low input East African Highland banana (Musa spp.) cropping systems

East African highland bananas (Musa spp., AAA-EA group) are a primary food and cash crop for smallholders in Rwanda and much of the East African highlands. Their production generally declines over time due to poor farm management and declining soil fertility. Farmers believe that among the bunch mass maintaining factors, plant density management offers some prospect. They often decrease banana mat (i.e. a single mother plant with interconnected suckers) density in an effort to increase bunch size, but the effectiveness and profitability of this practice has not been studied. In addition, not much research has been executed on the influence of climatic and edaphic factors on variations in on-farm plant density. An on-farm survey was conducted in contrasting agro-ecological sites of Rwanda (Ruhengeri, Rusizi, Karongi, Butare, Ruhango, Kibungo and Bugesera) to determine existing densities and their relationship to bunch mass. A plant density assessment method was used that measures the average distance of five mats to their respective nearest four mats to calculate average mat spacing. Plant density positively correlated with surplus/deficit water supply (i.e. difference between rainfall and water demand by bananas) (r 2 =0.62), with highest plant densities (>1500matsha -1 ) found in high rainfall areas (>1200mmyr -1 ) with water surplus (218-508mmyr -1 ) and lowest plant densities (1000-1400matsha -1 ) found in lower rainfall areas (1000-1200mmyr -1 ) with water deficit (from -223 to -119mmyr -1 ). Heaviest bunches (18.1-20.8kgfreshmassplant -1 ) were found at lowest plant densities and medium sized bunches (14.7-15.5kg) at highest plant densities. Lower soil and banana leaf nutrient contents (especially N, K, Ca and Mg) were observed on weathered soils (Acrisols) and were associated with smaller bunch mass in comparison to fertile soils (Andosols, Nitisols). Farmers tended to reduce mat densities (i) if they wanted to intercrop bearing in mind site characteristics, and (ii) to increase bunch mass to adapt to market preferences. The plant densities generally recommended by extension bodies (3m×3m or 2m×3m; i.e. 1111 and 1666matsha -1 , respectively) are seldom practiced by farmers, nor do they seem to be very appropriate, as higher densities seem productive in areas with high rainfall and relatively good soil fertility. © 2012 Elsevier B.V..status: publishe

Induction of oxidative stress related responses in

The reactive oxygen species (ROS)-signaling pathway is very important in heavy metal toxicity. Induction of the antioxidative defense mechanism, comprising ROS-scavenging enzymes and metabolites, in plants after environmental uranium contamination has been insufficiently studied in the past. This study aimed to analyze oxidative stress related responses in Arabidopsis thaliana after uranium exposure. Seventeen-day-old seedlings were exposed to 0, 0.1, 1, 10 and 100 μM uranium for 3 days. After exposure to 100 μM uranium, a decrease in fresh weight for leaves and roots was observed, leaves colored anthocyanous and roots were stunted and yellow. To reveal the importance of oxidative stress in uranium toxicity, alterations in ROS-scavenging enzymes were studied at protein and transcriptional level. Superoxide dismutase (SOD) capacities increased in leaves and roots after exposure to 100 μM uranium but no differences were observed for catalase (CAT) capacities. Transcript levels of different SODs located at various cellular compartments were affected depending on the place of action. Gene expression of CAT in leaves and roots was also affected after uranium exposure. Results indicate that oxidative stress plays an important role in uranium toxicity but suggest that plant responses differ for leaves and roots

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Infrastructure: databases, sample banks, methods and facilities for radioecological research

The overarching goal of STAR Work Package 2 "Integration and Infrastructure" is to facilitate the long term sustainable integration of European radioecological research, with an appropriate governance structure. To ensure effective collaboration and integration, an inventory of infrastructure covering radioanalytical equipment and methods, bioinformatic equipment and methods, sample archives, models, expertise and facilities for radioecological research has been created (using an on‐line wiki pages). The infrastructure survey shows that STAR partners and the associated Alliance have a high‐quality infrastructure, extended expertise and competence for radioecological research in Europe. STAR partners have expertise in wide‐ranging areas of radioecology, encompassing the atmospheric dispersion, dosimetry, ecology, ecotoxicology, environmental radiation protection, environmental surveillance, foodstuffs, terrestrial, freshwater and marine radioecology, modelling, radiobiology and radionuclide analytics, emergency preparedness, education and training. Within STAR partners have more than 170 experts are covering these areas. A wide‐ranging expertise is available within STAR partners for radioanalytical methods. Many of the methods are accredited emphasising the remarkably high quality of the partner laboratories. There are also many different holistic bioinformatic equipment and platforms for molecular and biochemical analysisto study (radiation) effects endpoints in Europe. The STAR NoE is highly resourced. The large inventory of specialized facilities and research equipment highlights the ability of the STAR network to perform high‐quality radioecological research. The facilities comprise different kinds of laboratories, such as rooms for: pretreatment of samples, specially constructed experimental systems for radioecological and biological studies and measurement, specialized equipment for radioactivity measurements, radiochemical and biological treatment of samples and organisms. The STAR NoE also holds a large variety of samples from the terrestrial and aquatic environment, and samples from a variety of air samplers collected by a various methods. These samples can be analysed systematically in future to address help address scientific questions in a cost effective manner (e.g. to improve parameter values within WP3 or help meet research requirements outlined in the STAR Strategic Research Agenda see www.star‐radioecology.org). The partners have collected samples during environmental surveillance programmes, within research projects and as a service for customers. Some of the archived samples were collected as early as the 1910s, but most are more recent. Some institutes do not have sample archives of their own, but their samples have been archived elsewhere. Amongst the STAR partners, expertise covers at least 40 different models for radioecological purposes. These covers many challenging fields in area of radioecology like radionuclides atmospheric dispersion, deposition and transport of radioactivity in the aquatic and terrestrial environment. The models are used for calculations of the dose rates, activity concentrations and assessment of risk from ionising radiation. Some of the models are also used for calculating stability diagrams, the equilibrium states, for transport of multiple components, mixed equilibrium and kinetic biogeochemical reactions, as well as various groundwater flow systems, which are designed to simulate aquifer systems. The focus of the models is on human and biota impact assessment. STAR partners are often both users and developers of the models. The SWOT analysis of the STAR infrastructure survey indicated many strengths and opportunities. Most of the strengths are related to integration, knowing and understanding the perspectives of each partner, a wide range of equipment, methods, analytical capacities, and expertise available for common research. This information could also be used for coordination and integration in response to emergencies. In the future, the potential of the infrastructure database is for training and to explore the potential for collaboration between STAR/ALLIANCE and other research organisations, international organizations (e.g. IAEA) and other platforms (NERIS, HERCA, MELODY). The infrastructure database also requires further development, in particular the need for maintenance and updating. The data in the infrastructure wiki pages must be real time