Chemical composition, antioxidant and insecticidal activities of a new essential oil chemotype of Pinus nigra ssp. mauritanica (Pinaceae), northern Algeria

Essential oil (EO) of aerial parts (twigs and needles) of an Algerian-Moroccan endemic pine Pinus nigra Arn. ssp. mauritanica (Mair. & Pey.) (Pinaceae) collected in Northern Algeria were extracted by hydrodistillation (HD) and solid phase micro-extraction (SPME). The compounds were analysed using Gas Chromatography (GC) and GC-Mass Spectrometry (GC-MS). The mean oil yield was 0.23%, for twigs and 0.47% for needles. 83 and 91 compounds have been identified for needles and twigs respectively. Chemical divergences from all other studied Black pines worldwide were observed in needles where the major components identified by HD are β-caryophyllene (26.2%), germacrene D (17.2%), α-pinene (9.4%) unveiling a new chemotype. Significative qualitative and quantitative differences were observed in chemical composition, depending on both technics HD and SPME. Twigs showed a higher potential for the antioxidant activities DPPH, ABTS and β-carotene system than EO needles. In other hand, needles revealed a higher activity for all concentrations than twigs with significant differences (p < 0.05). For phosphomolybden tests, both EOs exhibited more significant antioxidant potential compared to the DPPH, ABTS, β-carotene and reducing power systems. Noticeable insecticidal effects with variable rate depending on used plant parts, concentration, duration and frequency of exposure were also observed

Effets transgénérationnels d'une exposition parentale chez l'espèce sentinelle Gammarus fossarum

International audienceSince the 80s, the development of molecular biomarkers is an important component of ecotoxicology. Unfortunately, field studies that univocally link biomarker responses to fitness impacts and finally to population level are scarce. This is mainly due to the discordance in time scales between toxicological and ecological responses. In previous studies and under laboratory conditions with high contamination levels, a direct link has been established between genotoxic impacts in gametes of the sentinel species Gammarus fossarum, and impairment in embryos production. However, in a previous field study, abnormal genotoxic impacts levels observed in gametes, lower than ones obtained under laboratory exposure, failed to demonstrate rapid consequence on the production of embryos by exposed genitors. Taking advantage of the availability of multiple scale marker measurement in this species, from molecular (Comet assay, global DNA methylation) to physiological (feeding rate, molting success, vitellogenesis) and life history traits (growth, fertility, embryonic survival), along with the possibility to conduct rearing culture in the lab (time to puberty about 4 months), the objective of this study was to assess whether biomarker responses recorded in adult gammarids exposed to chemical stress may be predictive of long term effects on the fitness of their future progeny (i.e. transgenerational effects). For this, exposure of genitors to cadmium as model compound in the lab at environmentally relevant concentrations (0.3 and 3 µg/L) was followed by a post-exposure population culture of at least F1 and F2 individuals in uncontaminated conditions. Feeding rates (leaf disc surface measurements) of exposed organisms did not differ significantly from control individuals (Mann Whitney test p>0.05). The number of oocyte per female and the indicator of investment in oocyte quality (oocyte volume) of exposed females were also not significantly different compared to control organisms. In contrast, the first results analyzed on the F1 generation demonstrated a sharp significant effect of F0 parental cadmium exposure on the embryo number produced by F1 females after 6 months of lab maintenance in uncontaminated conditions (figure 3). Hence, exposure at environmentally relevant level of cadmium which only induces weak biomarker response (here sperm DNA damage) could generate an important delayed decrease in the population recruitment for future generations of this sentinel invertebrate species. To further assess population consequence of such effect, we plan to integrate these effects in the demographic population model available in Gammarus fossarum (5). Establishing a causal link between sperm DNA damage and drop in future generations is too speculative at this stage because other pathways of toxicity could be in cause in this transgenerational effects. Nevertheless, regarding our results on reproduction of these individuals (feeding rate and oocyte areas), We can discard the hypothesis of a limitation of investment by F0 females in F1 generation during Cd exposure. In addition to these results, other markers are being further analyzed (epigenetic marker and growth rate). Similar measurements will be done in the F2 generation in the next few weeks.This study enhances the importance to scrutinize transgenerational and delayed impacts of contaminant exposure, and the relevance of invertebrate species such as Gammarus to address this issue. Ongoing experiments considering field exposure of caged gammarids are implemented in order to generalize the outcome of this first laboratory case study

SILAR deposition of Ni(bpy)3X: {X = (NCS)2, (Fe(CN)5NO), and (Ag(CN)2)2} thin films on glass substrates

The authors focused on the preparation of thin layers based on hybrid materials (organometallic complexes) deposited onto glass substrates. The deposition experiments of [Ni(bpy)3](NCS)2, [Ni(bpy)3](Ag(CN)2)2, and [Ni(bpy)3](Fe(CN)5NO) were performed on glass slides (18 mm × 18 mm) by successive ionic layer adsorption and reaction (SILAR) method. The influence of some parameters, such as dipping cycle numbers (30, 60, and 120 dipping cycles), temperature (20°C, 30°C, 40°C, and 50°C), precursors concentration (10−3, 10−2, and 10−1 M), and the nature of the counteranions (NCS−, [Fe(CN)5NO]−2, [Ag(CN)2]−) were studied. Different methods (UV-Vis, SEM, FTIR, and XRD) were used to characterize the deposited layers to determine the absorption coefficient (α) and gap energy (Eg) of the materials

Utilisation de Gammarus sp. en écotoxioclogie. Etude de cas avec l'insecticide régulateur de croissance fénoxycarbe

International audienceGammarus sp. (Amphipoda) are widely distributed across European freshwater systems. In the present study, we evaluated the effect of a fenoxycarb exposure on Gammarus sp.. More specifically, i) we assessed the sensitivity of the embryo stage, ii) we identified embryogenesis' sensitive period, iii) we evaluated the sensitivity of the reproductive period and iv) we compared the response to fenoxycarb exposure among three European gammarid species. Fenoxycarb is a growth regulator insecticide, analog of the insect juvenile hormone, used for pest management and for veterinary purpose. This study demonstrated that 5 and 50 µg