Functional significance of genotoxicity in fish germ cells

The aquatic environment is becoming increasingly contaminated by pollutants having a genotoxic potential towards organisms and in particular in fish. Such genotoxins are prone to affect directly offspring or indirectly through the reproductive process. All this could influence recruitment rate and hence the population dynamics. However, assessment of the ecological risks associated with environmental genotoxic exposure is usually based on individual responses. Thus, there is a need for a better understanding of the long term and population level implications of genotoxic insults in fish. While low levels of DNA damage in somatic cells and oocytes can be efficiently repaired, mature sperm cells, i.e. spermatozoa, are susceptible to accumulate damage due to their lack of repair capacity. The present work aims to track the transfer of toxic effects across generations by studying the link between the level of DNA damage in fish sperm, and the rate of development abnormalities measured in the offspring after parental exposure to the model genotoxicant MMS. Three different fish species were chosen based either on their ecological importance or on their reproduction behavior, respectively brown trout (Salmo trutta), Arctic charr (Salvelinus alpinus) and threespine stickleback (Gasterosteus aculeatus). Results show a significant increase in sperm DNA damage measured with the comet assay in exposed organisms. This damage did not impact on fertilization success but led further to a significant increase in embryo abnormality rate at early embryonic and late larval stages, and further delayed growth in exposed group compared to the control

The Application of X-Band Radar for Characterisation of Nearshore Dynamics on a Mixed Sand and Gravel Beach

Remote sensing using X-band radar allows the estimation of wave parameters, near surface currents and the underlying bathymetry. This paper explores the use of radar to derive nearshore bathymetry at a complex site, at Thorpeness in Suffolk, UK. The site has a history of sporadic and focused erosion events along the beach frontage and as part of the X-Com project (X-band Radar and Evidence-Based Coastal Management Decisions) a radar system was deployed with the aim of further understanding the complex nearshore sediment processes influencing erosion. Initially, the bathymetric variation at the site is quantified through analysis of current and historic multibeam surveys. These indicate depth changes approaching 3 m. Subsequently, validation of the radar data against concurrent multibeam survey data has been undertaken. Results show that the radar derived bathymetry has a precision of ±1m at the site, with the largest errors being associated with areas of more complex bathymetry and where wave data quality was less suitable for analysis by the X-band radar bathymetry algorithms. It is concluded that although the accuracy of radar-derived bathymetry is lower than traditional multibeam survey, the low cost for high temporal coverage can be utilised for long-term monitoring of coastal sites where a cost-effective means of quantifying large-scale bathymetric changes is required

High-pressure investigations of CaTiO3 up to 60 GPa using X-ray diffraction and Raman spectroscopy

In this work, we investigate calcium titanate (CaTiO3 - CTO) using X-ray diffraction and Raman spectroscopy up to 60 and 55 GPa respectively. Both experiments show that the orthorhombic Pnma structure remains stable up to the highest pressures measured, in contradiction to ab-initio predictions. A fit of the compression data with a second-order Birch-Murnaghan equation of state yields a bulk modulus K0 of 181.0(6) GPa. The orthorhombic distortion is found to increase slightly with pressure, in agreement with previous experiments at lower pressures and the general rules for the evolution of perovskites under pressure. High-pressure polarized Raman spectra also enable us to clarify the Raman mode assignment of CTO and identify the modes corresponding to rigid rotation of the octahedra, A-cation shifts and Ti-O bond stretching. The Raman signature is then discussed in terms of compression mechanisms.Comment: 11 pages, 6 figures, 4 table

Bifunctional bispidine derivatives for copper-64 labelling and positron emission tomography

International audienc

The first radiosynthesis of 2-amino-5-[18F]fluoropyridines via a “minimalist” radiofluorination/palladium-catalyzed amination sequence from anisyl(2-bromopyridinyl)iodonium triflate

LDM TEPInternational audienc

Dynamic Performance and Characterization of Traps Using Different Measurements Techniques for the New AlGaN/GaN HEMT of 0.15-μm Ultrashort Gate Length

International audienc

A Bispidol Chelator with a Phosphonate Pendant Arm: Synthesis, Cu(II) Complexation, and (64)Cu Labeling

International audienceHere we present the synthesis and characterization of a new bispidine (3,7-diazabicyclo[3.3.1]nonane) ligand with N-methanephosphonate substituents (L2). Its physicochemical properties in water, as well as those of the corresponding Cu(II) and Zn(II) complexes, have been evaluated by using UV-visible absorption spectroscopy, potentiometry, (1)H and (31)P NMR, and cyclic voltammetry. Radiolabeling experiments with (64)Cu(II) have been carried out, showing excellent radiolabeling properties. Quantitative complexation was achieved within 60 min under stoichiometric conditions, at room temperature and in the nanomolar concentration range. It was also demonstrated that the complexation occurred below pH 2. Properties have been compared to those of the analogue bispidol bearing a N-methanecarboxylate substituent (L1). Although both systems meet the required criteria to be used as new chelator for (64/67)Cu in terms of the kinetics of formation, thermodynamic stability, selectivity for Cu(II), and kinetic inertness regarding redox- or acid-assisted decomplexation processes, substitution of the carboxylic acid function by the phosphonic moiety is responsible for a significant increase in the thermodynamic stability of the Cu(II) complex (+2 log units for pCu) and also leads to an increase in the radiochemical yields with (64)Cu(II) which is quantitative for L2

Evaluation of a bispidine‐based chelator for gallium‐68 and of the porphyrin conjugate as PET/PDT theranostic agent

In this study a bispidine ligand has been applied to the complexation of gallium(III) and radiolabelled with gallium-68 for the first time. Despite its 5-coordinate nature, the resulting complex is stable in serum for over two hours, demonstrating a ligand system well matched to the imaging window of gallium-68 positron emission tomography (PET). To show the versatility of the bispidine ligand and its potential use in PET, the bifunctional chelator was conjugated to a porphyrin, producing a PET/PDT-theranostic, which showed the same level of stability to serum as the non-conjugated gallium-68 complex. The PET/PDT complex killed >90 % of HT-29 cells upon light irradiation at 50 μm. This study shows bispidines have the versatility to be used as a ligand system for gallium-68 in PET