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•Plastic particles crossing the intestinal barrier is debated.•PS-NP particles were tested in ex-vivo time series experiments using Ussing chambers.•Two PS-NP concentrations were ...tested on two locations of adult Seabass guts.•PS-NP directly crossed the intestinal barrier of adult Seabass within few minutes.•PS-NP translocation was confirmed by 3 complementary techniques.
Plastic pollution in marine ecosystems constitutes an important threat to marine life. For vertebrates, macro/microplastics can obstruct and/or transit into the airways and digestive tract whereas nanoplastics (NPs; < 1000 nm) have been observed in non-digestive tissues such as the liver and brain. Whether NPs cross the intestinal epithelium to gain access to the blood and internal organs remains controversial, however. Here, we show directly NP translocation across the intestinal barrier of a fish, the European seabass, Dicentrarchus labrax, ex vivo. The luminal side of median and distal segments of intestine were exposed to fluorescent polystyrene NPs (PS-NPs) of 50 nm diameter. PS-NPs that translocated to the serosal side were then detected quantitatively by fluorimetry, and qualitatively by scanning electron microscopy (SEM) and pyrolysis coupled to gas chromatography and high-resolution mass spectrometry (Py-GC-HRMS). Fluorescence intensity on the serosal side increased 15–90 min after PS-NP addition into the luminal side, suggesting that PS-NPs crossed the intestinal barrier; this was confirmed by both SEM and Py-GC-HRMS. This study thus evidenced conclusively that NPs beads translocate across the intestinal epithelium in this marine vertebrate.
Four strains were isolated from a spoiled whiting (Merlangius merlangus). All of them were able to grow aerobically from 4 to 30°C and also able to develop anaerobically in the presence of ...trimethylamine N‐Oxide (TMAO) at 25°C. Biochemical characterization did not allow identification of the strains species but showed that one of the four strains was unable to produce H₂S. Two strains synthetized an ornithine decarboxylase being potential putrescine producers. Results of carbon source use highlighted that the four strains were able to use citrate and d‐sucrose and one strain was not able to use l‐arabinose. Genotypic characterization of the strains thanks to 16S rRNA and gyrB partial gene sequencing led to their identification as members of Shewanella baltica species. These observations suggest that H₂S production may not be the most appropriate screening parameter for Shewanella species and further to monitor the development of spoilage flora. SIGNIFICANCE AND IMPACT OF THE STUDY: Shewanella is a complex genus composed of numerous and heterogeneous species. One of them Shewanella baltica has previously been described as one of the most important H₂S‐producing bacterial species in iced stored fish and may act as spoilage organism through the reduction of trimethylamine N‐Oxide (TMAO). Four strains of S. baltica were isolated from spoiled whiting (Merlangius merlangus), and description of three H₂S‐positive strains and one H₂S‐negative strain of S. baltica is highlighted in this short paper. Consequently, H₂S production might not be the most appropriate screening parameter to assess the development of spoilage organisms.
In this study, a novel analytical method to quantify prion inactivating detergent in rinsing waters coming from the washer-disinfector of a hospital sterilization unit has been developed. The final ...aim was to obtain an easy and functional method in a routine hospital process which does not need the cleaning product manufacturer services.
An ICP-MS method based on the potassium dosage of the washer-disinfector's rinsing waters was developed. Potassium hydroxide is present on the composition of the three prion inactivating detergent currently on the French market. The detergent used in this study was the Actanios LDI(®) (Anios laboratories). A Passing and Bablok regression compares concentrations measured with this developed method and with the HPLC-UV manufacturer method.
According to results obtained, the developed method is easy to use in a routine hospital process. The Passing and Bablok regression showed that there is no statistical difference between the two analytical methods during the second rinsing step. Besides, both methods were linear on the third rinsing step, with a 1.5ppm difference between the concentrations measured for each method.
This study shows that the ICP-MS method developed is nonspecific for the detergent, but specific for the potassium element which is present in all prion inactivating detergent currently on the French market. This method should be functional for all the prion inactivating detergent containing potassium, if the sensibility of the method is sufficient when the potassium concentration is very low in the prion inactivating detergent formulation.
Four strains were isolated from a spoiled whiting (Merlangius merlangus). All of them were able to grow aerobically from 4 to 30°C and also able to develop anaerobically in the presence of ...trimethylamine N-Oxide (TMAO) at 25°C. Biochemical characterization did not allow identification of the strains species but showed that one of the four strains was unable to produce H2 S. Two strains synthetized an ornithine decarboxylase being potential putrescine producers. Results of carbon source use highlighted that the four strains were able to use citrate and d-sucrose and one strain was not able to use l-arabinose. Genotypic characterization of the strains thanks to 16S rRNA and gyrB partial gene sequencing led to their identification as members of Shewanella baltica species. These observations suggest that H2 S production may not be the most appropriate screening parameter for Shewanella species and further to monitor the development of spoilage flora.
Shewanella is a complex genus composed of numerous and heterogeneous species. One of them Shewanella baltica has previously been described as one of the most important H2 S-producing bacterial species in iced stored fish and may act as spoilage organism through the reduction of trimethylamine N-Oxide (TMAO). Four strains of S. baltica were isolated from spoiled whiting (Merlangius merlangus), and description of three H2 S-positive strains and one H2 S-negative strain of S. baltica is highlighted in this short paper. Consequently, H2 S production might not be the most appropriate screening parameter to assess the development of spoilage organisms.
Le
rewilding
est un terme récent mais déjà polysémique, ce qui donne lieu à des critiques relatives à la cohérence des projets s’en réclamant ainsi qu’à leur capacité à proposer une nouvelle ...direction pour l’action écologique. Sa définition la plus directe, comme principe d’action écologique visant à rendre un élément (espace, espèce, écosystème) à nouveau sauvage, pose elle-même question. Le recours à la notion d’autonomie plus qu’humaine permet de surmonter ces critiques : les initiatives de
rewilding
impliquent un décentrement des êtres humains de l’action écologique et sont à envisager comme des agencements humains/autres qu’humains sans but prédéfini. L’approche de géographie plus qu’humaine apporte une nouvelle perspective à l’étude de cet objet et plus largement à la réflexion sur les relations au sauvage et au vivant dans son ensemble.
This article offers a critical review of literature concerning the emerging topic of rewilding. It deals with different meanings and uses of the term: trophic rewilding, Pleistocene rewilding, rewilding through the action of herbivores, individual rewilding, rewilding on islands, flora rewilding, spontaneous or passive rewilding, rewilding of abandoned landscapes and even rewilding of humans. Although a recent notion, with first references published in the 1990s, rewilding is already polysemic and faces criticism regarding its coherence and capacity to offer new directions to ecological action. Its most common understanding as a principle of ecological action aiming to bring an individual, a species, an ecosystem or place back to a wilder state, also raises some issues. It infers a will to go back to a former state and reactivates the idea that some spaces are free from human influence and should thus be considered wild and therefore protected. We could overcome these issues by characterizing rewilding as centred on the notion of more-than-human autonomy. Indeed, rewilding projects aim at a decentring of anthropocentric ecological action and could be seen as human/other-than-human arrangements. This shift in the definition of rewilding enables us to see it as an open-ended and more-than-human process rather than as human-managed and goal-oriented. More-than-human geography offers a new approach to current reflexions on rewilding and on how to live in more-than-human worlds.
For seventy years, mass plastic production and waste mismanagement have resulted in huge pollution of the environment, including the marine environment. The first mention of seafood contaminated by ...microplastics was recorded in the seventies, and to date numerous studies have been carried out on shellfish, fish and crustaceans. Based on an ad hoc corpus, the current review aims to report on the numerous practices and methodologies described so far. By examining multiple aspects including problems related to the definition of the term microplastic, contamination at the laboratory scale, sampling and isolation, and quantification and identification, the aim was to point out current limitations and the needs to improve and harmonise practices for future studies on microplastics in seafood. A final part is devoted to the minimum information for publication of microplastics studies (MIMS). Based on the aspects discussed, MIMS act as a starting point for harmonisation of analyses.
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•Need for new and more complete definition of microplastics.•Discussion on contamination prevention in the laboratory environment.•Recommendations on sampling and isolation.•Recommendations on quantification and identification.•Proposition of minimum information for publication of microplastics studies.
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