The first case exploring the health management of dogs owned by a man suffering from Ebola (EVD) in Italy

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Microplastics Uptake and Egestion Dynamics in Pacific Oysters, Magallana gigas (Thunberg, 1793), Under Controlled Conditions

Microplastics debris (< 5 mm) are increasingly abundant in the marine environment, therefore, potentially becoming a growing threat for different marine organisms. Through aquatic animals, these can enter in the human food chain, and can be perceived as a risk for consumers’ health. Different studies report the presence of particles in marketable shellfish including the world wide commercially grown Pacific oyster Magallana gigas (Thunberg, 1793). The aim of this study is to examine the potential risk of microplastics entering in the human food chain through this shellfish species, investigating the dynamics of the uptake, egestion (faeces) and rejection (pseudofaeces) of microplastics in Pacific oysters under controlled conditions. M. gigas collected from a farm in the San Teodoro lagoon (Italy), were exposed to 60 fluorescent orange polystyrene particles L−1 of known sizes (100, 250 and 500 μm). The uptake of each particle size was 19.4 ± 1.1%, 19.4 ± 2% and 12.9 ± 2% respectively. After exposure M. gigas were left to depurate for 72 h, during which 84.6 ± 2% of the particles taken up were released whilst 15.4 ± 2% were retained inside the shell cavity. No microplastic particles were found in the animals’ soft tissues. The results of this study, suggest that depuration is an effective method to reduce presence of large microplastic particles, in the size range 100–500 μm, in M. gigas. Importantly, the data suggests that the burden that could theoretically be up taken by consumers from these shellfish is negligible when compared to other routes

Immunotoxicity of polystyrene nanoplastics in different hemocyte subpopulations of Mytilus galloprovincialis

Plastic represents 60-80% of litter in the ocean. Degradation of plastic to small fragments leads to the formation of microplastics (MPs <5mm) and nanoplastics (NPs <1 mu m). One of the most widely used and representative plastics found in the ocean is polystyrene (PS). Among marine organisms, the immune system of bivalves is recognized as suitable to assess nanomaterial toxicity. Hemocyte subpopulations [R1 (large granular cells), R2 (small semi-granular cells) and R3 (small agranular or hyaline cells)] of Mytilus galloprovincialis are specialized in particular tasks and functions. The authors propose to examine the effects of different sizes (50 nm, 100 nm and 1 mu m) PS NPs on the different immune cells of mussels when they were exposed to (1 and 10mg.L-1) of PS NPs. The most noteworthy results found in this work are: (i) 1 mu m PS NPs provoked higher immunological responses with respect to 50 and 100nm PS NPs, possibly related to the higher stability in size and shape in hemolymph serum, (ii) the R1 subpopulation was the most affected with respect to R2 and R3 concerning immunological responses and (iii) an increase in the release of toxic radicals, apoptotic signals, tracking of lysosomes and a decrease in phagocytic activity was found in R1

Sampling, isolating and identifying microplastics ingested by fish and invertebrates

Microplastic debris (<5 mm) is a prolific environmental pollutant, found worldwide in marine, freshwater and terrestrial ecosystems. Interactions between biota and microplastics are prevalent, and there is growing evidence that microplastics can incite significant health effects in exposed organisms. To date, the methods used to quantify such interactions have varied greatly between studies. Here, we critically review methods for sampling, isolating and identifying microplastics ingested by environmentally and laboratory exposed fish and invertebrates. We aim to draw attention to the strengths and weaknesses of the suite of published microplastic extraction and enumeration techniques. Firstly, we highlight the risk of microplastic losses and accumulation during biotic sampling and storage, and suggest protocols for mitigating contamination in the field and laboratory. We evaluate a suite of methods for extracting microplastics ingested by biota, including dissection, depuration, digestion and density separation. Lastly, we consider the applicability of visual identification and chemical analyses in categorising microplastics. We discuss the urgent need for the standardisation of protocols to promote consistency in data collection and analysis. Harmonized methods will allow for more accurate assessment of the impacts and risks microplastics pose to biota and increase comparability between studies

Understanding How Microplastics Affect Marine Biota on the Cellular Level Is Important for Assessing Ecosystem Function: A Review

Plastic has become indispensable for human life. When plastic debris is discarded into waterways, these items can interact with organisms. Of particular concern are microscopic plastic particles (microplastics) which are subject to ingestion by several taxa. This review summarizes the results of cutting-edge research about the interactions between a range of aquatic species and microplastics, including effects on biota physiology and secondary ingestion. Uptake pathways via digestive or ventilatory systems are discussed, including (1) the physical penetration of microplastic particles into cellular structures, (2) leaching of chemical additives or adsorbed persistent organic pollutants (POPs), and (3) consequences of bacterial or viral microbiota contamination associated with microplastic ingestion. Following uptake, a number of individual-level effects have been observed, including reduction of feeding activities, reduced growth and reproduction through cellular modifications, and oxidative stress. Microplastic-associated effects on marine biota have become increasingly investigated with growing concerns regarding human health through trophic transfer. We argue that research on the cellular interactions with microplastics provide an understanding of their impact to the organisms’ fitness and, therefore, its ability to sustain their functional role in the ecosystem. The review summarizes information from 236 scientific publications. Of those, only 4.6% extrapolate their research of microplastic intake on individual species to the impact on ecosystem functioning. We emphasize the need for risk evaluation from organismal effects to an ecosystem level to effectively evaluate the effect of microplastic pollution on marine environments. Further studies are encouraged to investigate sublethal effects in the context of environmentally relevant microplastic pollution conditions

Effets du diuron et de l’irgarol chez deux souches de Tetraselmis suecica : la résistance au diuron s'accompagne-t-elle d'une résistance à l’irgarol ?

National audienceL’irgarol et le diuron sont deux biocides inhibiteurs de la photosynthèse agissant au niveau du photosystème II. Leur toxicité seule et en mélange, a été évaluée sur deux souches de la micro-algue marine Tetraselmis suecica : une souche sauvage « WT » et une souche résistante au diuron, « MT », obtenue précédemment au laboratoire. Les effets ont été mesurés sur le temps de doublement (TD), l’efficacité photosynthétique (Φ’M), ainsi que le contenu relatif en espèces réactives de l’oxygène (ROS) et en lipides. Les deux souches ont été exposées en laboratoire aux concentrations 0.05, 0.1 et 0.5 µg.L-1 d’irgarol (I), 0.5, 1 et 5 µg.L-1 de diuron (D), et à quatre mélanges binaires (A : D5+I0.5 ; B : D5+I0.1 ; C : D1+I0.5 ; D : D1+I0.1) durant six jours. Afin d’identifier la cause de la résistance au diuron chez la souche MT, la séquence codante du gène psbA a été séquencée. Le séquençage a révélé l’existence d’une mutation unique dans la séquence codante du gène psbA de la souche MT, connue pour conférer une résistance à certains herbicides ciblant le photosystème II. Comme attendu, l’exposition de MT à D5 n’a induit aucun effet significatif ; en revanche, l’exposition de MT à I0.5 a engendré une augmentation significative du TD (+19%), similaire à celle obtenue chez la souche sauvage WT. Cela démontre que la mutation ne confère pas de résistance à l’irgarol. Après exposition au mélange A, MT a montré une augmentation du TD supérieure (+66%) à l’effet obtenu avec l’irgarol seul, soulevant la question d’une possible synergie entre les deux molécules. Au niveau des autres paramètres, l’efficacité photosynthétique ainsi que le contenu lipidique relatif ont significativement diminué, alors que la quantité relative de ROS a significativement augmenté après exposition à : D5, I0.5, et aux mélanges A, B et C pour WT ; à I0.5 et aux mélanges A et C pour MT. L’exposition d’une souche résistante au diuron à ces deux herbicides soulève des questions quant aux mécanismes d’adaptation chez les micro-algues exposées à une contamination chimique

Toxicité de deux biocides anti-fouling, l'irgarol 1051 et le diuron, sur deux espèces marines de phytoplancton couramment utilisées en aquaculture

International audienceIrgarol 1051 and diuron are two booster biocides commonly used in antifouling paints. They target directly the photosystem II by inhibiting the electron transfer between QA and QB. As photosystem II structure does not vary much between different plant organisms and algae, numerous unwanted targets can be affected in case of environment contamination. The single and combined effects of these two compounds were investigated towards two marine phytoplankton species, Chaetoceros calcitrans (a single “wild” strain WC) and Tetraselmis suecica (two strains: “wild” (WT) and diuron-resistant mutant (MT)). The effects on growth, photosynthetic yield, reactive oxygen species presence and intracellular relative lipid content were assessed after a 6-day exposure to a range of concentrations from 0.01 µg.L-1 to 0.5 µg.L-1 for irgarol and from 0.5 to 5 µg.L-1 for diuron. Diuron induced a significant effect at 5 µg.L-1 for WT and WC, with an increase of their doubling time by 168% (± 20) and 14% (± 2) respectively. DCFH-DA fluorescence related to ROS presence showed an increase by 94% (± 3) compared to the control for WT. The diuron-resistant strain MT showed no significant effect at the end of the 6-day exposure to diuron 5 µg.L-1. Micro-algae exposure to 0.5 µg.L-1 irgarol also showed significant results, as doubling time increased by 54% (± 4) for WC and by 19% (± 2) for WT after a 6-day exposure. Photosynthetic yield decreased by 25% (± 0) for WC and by 17% (± 1) for WT. The mutant strain was greatly inhibited at 0,5 µg.L-1 irgarol with an increase of 63% (± 2) and 60% (± 8) of doubling time and DCFH-DA fluorescence, respectively. Finally, a 6-day exposure to a mixture of diuron and irgarol was performed, but results are still being acquired. The sequencing of the psbA gene of mutant strain is still ongoing. This study demonstrates the high toxicity of these two biocides to marine phytoplankton. It also demonstrates that resistance to diuron does not necessarily enables resistance to another PSII inhibitor. This highlights the need to monitor the fate of these two compounds in the environment, especially for irgarol, since it’s still authorized in many European countries

Différences de sensibilité entre une souche de microalgues résistante au diuron et deux souches sauvages, lors d'une exposition au diuron et à l'irgarol, seuls et en mélange

International audienceA wild strain of Chaetoceros calcitrans and wild and diuron-resistant strains of Tetraselmis suecica, were exposed to the PSII inhibitor herbicides diuron and irgarol, individually and in mixtures. The effects of three concentrations of diuron and irgarol and four binary mixtures were evaluated on doubling time, relative reactive oxygen species and lipid content by flow cytometry, and on photosynthetic efficiency by pulse amplitude modulated fluorescence. In both wild strains, significant effects were observed for each molecule at the highest concentration tested: at irgarol 0.5 microg L-1, C. calcitrans was shown to be more sensitive than T. suecica (+52% and +19% in doubling time, respectively), whereas at diuron 5 microg L-1, T. suecica was more affected (+125% in doubling time) than C. calcitrans (+21%). Overall, irgarol had a higher toxicity at a lower concentration than diuron (no effect at diuron 0.5 microg L-1) for both wild strains. The strongest mixture (irgarol 0.5 microg L-1 + diuron 5 microg L-1) increased doubling time by 356% for T. suecica, thus showing amplified effects when the two compounds were mixed. Sequencing of the diuron-resistant strain demonstrated a single mutation in the psbA gene coding sequence. Although resistance of this strain to diuron was confirmed with no effect at the highest diuron concentration, no resistance to irgarol was shown. In addition, the mutant strain exposed to the strongest mixture showed a 3.5-fold increase in doubling time compared with irgarol alone, thereby supporting the hypothesis of a biochemical interaction between these two compounds