24 research outputs found

    Use of models for the environmental risk assessment of veterinary medicines in European aquaculture: current situation and future perspectives

    Get PDF
    Veterinary Medicinal Products (VMPs) are used in intensive aquaculture production to treat a wide range of bacterial and parasitic infestations. Their release into the environment poses concerns regarding their potential ecotoxicological risks to aquatic ecosystems, which need to be evaluated making use of appropriate Environmental Risk Assessment (ERA) schemes and models. This study presents an overview of the major aquaculture production systems in Europe, the VMPs most commonly used, and the environmental quality standards and regulatory procedures available for their ERA. Furthermore, it describes the state-of-the-art on the development of environmental models capable of assessing the fate, exposure, ecotoxicological effects and risks of VMPs in aquaculture production systems, and discusses their level of development and implementation within European aquaculture. This study shows that the use of environmental models in regulatory ERA is somewhat limited in many European countries. Major efforts have been dedicated to assess the fate and exposure of antiparasitic compounds in salmonid cage systems, particularly in Scotland, while models and scenarios for assessing dispersal of antimicrobials, in general, and antiparasitic compounds in the Mediterranean as well as in Scandinavian regions are less available. On the other hand, the use of ecological models for assessing the effects and risks of VMPs is almost absent. Recommendations are provided to improve the chemical exposure and effect assessments and the ecological realism of the modelling outcomes, paying special attention to the protection goals set for the regulatory ERA of VMPs in Europ

    Circadian oscillator proteins across the kingdoms of life : Structural aspects 06 Biological Sciences 0601 Biochemistry and Cell Biology

    Get PDF
    Circadian oscillators are networks of biochemical feedback loops that generate 24-hour rhythms and control numerous biological processes in a range of organisms. These periodic rhythms are the result of a complex interplay of interactions among clock components. These components are specific to the organism but share molecular mechanisms that are similar across kingdoms. The elucidation of clock mechanisms in different kingdoms has recently started to attain the level of structural interpretation. A full understanding of these molecular processes requires detailed knowledge, not only of the biochemical and biophysical properties of clock proteins and their interactions, but also the three-dimensional structure of clockwork components. Posttranslational modifications (such as phosphorylation) and protein-protein interactions, have become a central focus of recent research, in particular the complex interactions mediated by the phosphorylation of clock proteins and the formation of multimeric protein complexes that regulate clock genes at transcriptional and translational levels. The three-dimensional structures for the cyanobacterial clock components are well understood, and progress is underway to comprehend the mechanistic details. However, structural recognition of the eukaryotic clock has just begun. This review serves as a primer as the clock communities move towards the exciting realm of structural biology

    Behavior of simetryn and thiobencarb in the plough zone of Rice Fields

    No full text
    The behavior of simetryn and thiobencarb in flooded rice soil was investigated in a 2-year study. The concentrations of simetryn and thiobencarb were in the hundreds of μg kg-1 in the top soil layer (0-5 cm) and became significantly lower in tens of μg kg-1 in the deeper soil layers (5-10 and 10-15 cm). The half-lives of the two herbicides were also shorter (36 and 17 days for simetryn and thiobencarb, respectively) in the top soil layer, as they were most affected by environmental conditions, compared with corresponding values of 82 and 69 days in the 5-10 cm soil layer. Simetryn concentration was stable, while thiobencarb's half-life was 165 days in the 10-15 cm layer. About 35% of the applied mass of simetryn and thiobencarb were found in the rice soil compartment

    Fate and transport of bensulfuron-methyl and imazosulfuron in paddy fields: Experiments and model simulation

    No full text
    Experiments were conducted to determine the fate of bensulfuron-methyl (BSM) and imazosulfuron (IMS) under paddy conditions. Initially, laboratory experiments were conducted and the photolysis half-lives of the two herbicides were found to be much shorter than their hydrolysis half-lives in aqueous solutions. In the aerobic water-soil system, dissipation followed first-order kinetics with water half-lives of 9. 1 and 11. 0 days and soil half-lives of 12. 4 and 18. 5 days (first phase) and 35. 0 and 44. 1 days (second phase) for bensulfuron-methyl and imazosulfuron, respectively. However, the anaerobic soil half-lives were only 12. 7 and 9. 8 days for BSM and IMS, respectively. The values of K were determined to be 16. 0 and 13. 8 for BSM and IMS, respectively. Subsequent field measurements for the two herbicides revealed that dissipation of both herbicides in paddy water involved biphasic first-order kinetics, with the dissipation rates in the first phase being much faster than those in the second phase. The dissipation of bensulfuron-methyl and imazosulfuron in the paddy surface soil were also followed biphasic first-order kinetics. These results were then used as input parameters for the PCPF-1 model to simulate the fate and transport of BSM and IMS in the paddy environment (water and 1-cm surface soil layer). The measured and simulated values agreed well and the mass balance error during the simulation period was -1. 2 and 2. 8% of applied pesticide, respectively, for BSM and IMS
    corecore