Cakile maritima (Brassicaceae) is a halophyte that thrives on dunes along the Tunisian seashore. Besides its ecological interest for soil fixation, this plant produces seeds rich in lipids (40% on ...dry weight basis), making it a potential source of oil for industrial use. The purpose of the present work was to study the salt tolerance of this species at germination, vegetative growth and fruiting stages. NaCl inhibited germination only at concentrations higher than 200 mM, mainly by an osmotic effect (fully reversible after seed transfer to water). At the vegetative stage, the plant exhibited a typical halophytic behaviour, requiring the presence of a moderate salt concentration (50 to 100 mM NaCl) to express its maximal growth potentialities. Growth activity was maintained up to 500 mM NaCl. Salt tolerance of maritima at the vegetative stage seemed to be mainly based on: (i) the capacity to preserve the biomass production within the range of optimal salt concentrations; (ii) the ability to maintain the tissue water status; and (iii) the efficiency of selective K⁺ uptake, in spite of high Na⁺ concentration in the medium. Indirect evidence of Na⁺ utilisation by the plant for osmotic adjustment was obtained. Seed production was stimulated at 50 to 100 mM NaCl as compared to control treatment, and severely restricted at higher salt levels. Individual seed mass was moderately diminished by increasing NaCl concentrations.
Bisphenol A (BPA), a widespread man-made chemical classified as an endocrine disruptor, is increasingly considered as a major cause of concern for human health. Chlorine present in drinking water may ...react with BPA to form chlorinated derivatives (ClxBPA), which have demonstrated a heightened level of estrogenic activity. If many epidemiological studies report that more than 90% of people have detectable BPA levels in their urine, then no such study has been undertaken regarding ClxBPA. The purpose of this work is to propose a highly sensitive and accurate analytical method adapted to large-scale biomonitoring studies aimed at assessing exposure to BPA and ClxBPA through the use of human urine. To achieve this, we have comprehensively validated a method using salting-out assisted liquid/liquid extraction (SALLE) coupled to UPLC–MS/MS and isotope dilution quantification, to measure unconjugated BPA and ClxBPA in human urine according to the accepted guidelines. Deutered BPA as well as deutered 2,2′-DCBPA was used as internal standards. The matrix calibration curve ranged from 0.05 to 1.60ngmL−1 and from 0.5 to 16.0ngmL−1 for ClxBPA and BPA respectively, and provided good linearity (r²>0.99). This method was precise (the intra- and inter-day coefficients of variation were <20% at three different concentrations: 0.05ngmL−1, 0.2ngmL−1, 0.8ngmL−1 and 0.5ngmL−1, 2ngmL−1, 8ngmL−1 for ClxBPA and BPA, respectively) and accurate (bias ranged from −13% to +12%). The limit of quantification, validated at 0.05ngmL−1 and 0.5ngmL−1 for ClxBPA and BPA respectively when using 300µL of urine, was found to be suitable for the concentration existing in real samples. The matrix effect and the BPA cross-contamination were also investigated in this study. The analytical method developed in this study is in accordance with the requirements applicable to biomonitoring of BPA and ClxBPA in human urine.
BPA and ClxBPA were found in human urine samples using UPLC–MS/MS with SALLE. Display omitted
•An UPLC–MS/MS assay was developed for BPA and ClxBPA in urine in the pg/mL range.•Sample preparation used a simple salting-out liquid–liquid extraction (SALLE).•SIL-IS (BPA-d16 and DCBPA-d12) were used for quantification.•Assay was validated using standards and QCs prepared in human urine.•Sensitivity of the assay allows the determination of target analytes in human urine.
A front end ASIC (BiCMOS-SiGe
0.35
μ
m
) has been developed within the framework of the MIMAC detector project, which aims at directional detection of non-baryonic Dark Matter. This search strategy ...requires 3D reconstruction of low energy (a few keV) tracks with a gaseous
μ
TPC
. The development of this front end ASIC is a key point of the project, allowing the 3D track reconstruction. Each ASIC monitors 16 strips of pixels with charge preamplifiers and their time over threshold is provided in real time by current discriminators via two serializing LVDS links working at 320
MHz. The charge is summed over the 16 strips and provided via a shaper. These specifications have been chosen in order to build an auto triggered electronics. An acquisition board and the related software were developed in order to validate this methodology on a prototype chamber. The prototype detector presents an anode where 2×96 strips of pixels are monitored.
Thellungiella halophila seedlings grown on a solid substrate for 25 days on standard medium were challenged with NaCl. Growth, tissue hydration, ion accumulation, photosynthesis, lipid peroxidation ...and antioxidant enzymatic activities were studied on rosette leaves. Three accessions of
Arabidopsis thaliana were cultivated under the same conditions. During the first two weeks of salt treatment, the growth of
T. halophila leaves was restricted by NaCl. No significant difference appeared between
T. halophila and
A. thaliana concerning biomass deposition, or hydric and ionic parameters. However, all
A. thaliana plants displayed foliar damage, and died during the third week of salt (50
mM NaCl) treatment. Almost all (94%)
T. halophila plants remained alive, but did not display any sign of altered physiological condition. Tissue hydration, chlorophyll content, stomatal conductance, photosynthetic quantum yield, and photosynthetic rate were very similar to those of control plants. Lipid peroxidation, estimated from thermoluminescence, was very low and insensitive to salt treatment. Only slight changes occurred in antioxidant enzymatic activities (SOD, several peroxidases, and catalase). From the absence of physiological disorder symptoms, we infer that salt was efficiently compartmentalized in leaf vacuoles. In salt-treated
A. thaliana, the photosynthetic quantum yield was diminished, and lipid peroxidation was augmented. These observations reinforce the conclusion that
T. halophila could accumulate salt in its leaves without damage, in contrast to
A. thaliana.
Les conditions de sécurité sanitaire encadrant la pratique de l’hémodiafiltration en ligne (HDF-Ol) sont bien définies mais n’intègrent cependant pas encore les risques liés à la présence de ...perturbateurs endocriniens (PE) comme le bisphénol A (BPA). Pourtant nos récents travaux menés en hémodialyse (HD) ont démontré sa présence au niveau des dialyseurs et dans l’eau ultrapure servant à produire le dialysat. L’objectif de cette nouvelle étude est d’évaluer pour la 1re fois l’exposition au BPA mais également à ses 4 dérivés chlorés (Clx-BPA) (100 fois plus œstrogéniques que le BPA) : mono-, di-, tri- et tétra-chloro-BPA, lors du traitement par HDF-Ol.
Les échantillons ont été prélevés sur la boucle de traitement de l’eau ultrapure puis à différents temps de la production du dialysat et du liquide de substitution (LS). Nous avons également quantifié le BPA apporté par les dialyseurs utilisés en HDF-Ol dans notre institution. Les dosages ont été effectués à l’aide d’une technique LC-MS/MS.
Le BPA et ses Clx-BPA ont été détectés à l’entrée de la boucle de traitement d’eau et à chaque étape de sa purification (en moyenne 3,2, 0,3, 12,0, 0,2, 0,9ng/L respectivement pour le BPA, le mcBPA, dcBPA, tcBPA et le ttBPA). Le BPA a été retrouvé dans le dialysat (39ng/L) et dans le LS (1033ng/L) où la concentration du BPA décroît au cours du temps pour atteindre 265ng/L en fin de séance. Enfin, le BPA était présent dans tous les dialyseurs testés, à des concentrations pouvant atteindre 149,0ng/dialyseur dans le compartiment mimant le sang et jusqu’à 174,0ng/dialyseur dans le dialysat malgré un rinçage préalable avec 2L de NaCl 0,9 %.
Nos résultats démontrent que du BPA est apporté par le matériel utilisé en HDF-Ol (dialyseurs, ultrafiltre, cartouches de concentrés) mais également par l’eau servant à produire le dialysat et le LS. Ces derniers sont également contaminés par des Clx-BPA via l’eau ultrapure.
Notre étude est la 1re montrant le risque d’exposition au BPA et Clx-BPA en HDF-Ol. Une étude visant à évaluer l’impact de cette exposition chez le patient traité doit maintenant être envisagée mais la maîtrise de cette contamination pourrait d’ores et déjà s’intégrer aux pratiques (choix des dispositifs médicaux) et au procédé de traitement de l’eau.
The growth of the halophyte Sesuvium portulacastrum, commonly known as sea purslane, is impeded by NaCl only at high (600–1000 mM) concentration. Therefore, the goal of this investigation was to ...identify the mechanisms which set the limit of the salt resistance of S. portulacastrum. 21‐day‐old cuttings were grown for 45–50 d under split‐root conditions in which one half of the root system was immersed in complete nutrient solution supplemented with 800 mM NaCl, while the other half was immersed in a NaCl‐free medium, containing all nutrients or being deprived of potassium or calcium or nitrogen. Using this approach, we demonstrate that K+ and N uptake was impaired in roots exposed to NaCl. Concerning Ca2+, there was no indication of uptake inhibition by NaCl. However, restriction of K+ uptake by roots was compensated by an increase in the K+‐use efficiency, so that growth was not inhibited. Concerning N, our analysis shows that NO$ _3^- $ and/or NH$ _4^+ $ uptake, but not their assimilation, was limited by salt treatment. Thus, we conclude that at high salinity levels, the growth of S. portulacastrum is limited by the restrictions imposed by NaCl on N uptake, perhaps in addition to inhibiting effects of excessive Na+ accumulation in shoot.
Durch Salz bedingte Wachstumsbeeinträchtigungen des Halophyten Sesuvium portulacastrum
Das Wachstum des Halophyten Sesuvium portulacastrum (See‐Portulak) wird erst bei hohen (600–1000 mM) NaCl‐Konzentrationen beeinträchtigt. Wir haben die Mechanismen studiert, die die Salztoleranz von S. portulacastrum bei hohen Salzkonzentrationen begrenzen. Dazu wurden 21 Tage alte Stecklinge über einen Zeitraum von 45–50 Tagen in einem “split root“‐System kultiviert. Die eine Hälfte des Wurzelsystems wurde in Nährlösung eingetaucht, die 800 mM NaCl enthielt, die andere Hälfte in NaCl‐freie Lösung die alle Nährsalze enthielt, bzw. kein Kalium, kein Calcium oder keinen Stickstoff. Die erzielten Ergebnisse zeigen, dass NaCl die Aufnahme von K+ und N beeinträchtigt, während es keine Auswirkungen auf die Ca2+‐Aufnahme hat. Die Beeinträchtigung der K+‐Aufnahme wird kompensiert durch einen Anstieg der K+‐Nutzungseffizienz mit der Folge, dass das Wachstum unbeeinträchtigt bleibt. In Bezug auf N zeigen unsere Analysen, dass die Aufnahme von NO$ _3^- $ and NH$ _4^+ $ – aber nicht ihre Assimilation – durch die Salinität beeinträchtigt wird. Wir schließen daraus, dass die Wachstumsbeeinträchtigung von S. portulacastrum bei hoher Salinität vorwiegend auf die Beeinträchtigung der N‐Aufnahme, möglicherweise in Kombination mit exzessiver Na+‐Akkumulation im Spross, zurückzuführen ist.
Directional detection is a promising Dark Matter search strategy. Indeed, WIMP-induced recoils present a direction dependence toward the Cygnus constellation, while background-induced recoils exhibit ...an isotropic distribution in the galactic rest frame. Taking advantage on these characteristic features and even in the presence of a sizeable background, we show for the first time the possibility to constrain the WIMP properties, both from particle and galactic halo physics, leading to an identification of non-baryonic Dark Matter. However, such results need highly accurate track reconstruction which should be reachable by the MIMAC detector using a dedicated readout combined with a likelihood analysis of recoiling nuclei.
Directional detection of non-baryonic Dark Matter is a promising search strategy for discriminating WIMP events from background. However, this strategy requires both a precise measurement of the ...energy down to a few keV and 3D reconstruction of tracks down to a few mm. To achieve this goal, the MIMAC project has been developed. It is based on a gaseous micro-TPC matrix, filled with CF4 and CHF3. The first results on low energy nuclear recoils (1H and 19F) obtained with a low mono-energetic neutron field are presented. The discovery potential of this search strategy is discussed and illustrated by a realistic case accessible to MIMAC.
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