Search

International audience; ĂBecause of their antibacterial properties, silver (Ag) engineered nanomaterials are included in many products. The present study used a standardized Ag nanomaterial (NM-300K, 20 nm) supplied with a stabilizing agent. The aim was to investigate the behavior of Ag nanomaterial in an estuarine-like medium at 2 salinities (15 psu and 30 psu). Uptake as well as sublethal effects of Ag nanomaterial (10 μg Ag/L), its stabilizing agent, and AgNO3 (10 μg Ag/L) were assessed in the clam Scrobicularia plana, after 7 d of exposure. The release of soluble Ag from Ag nanomaterial in the experimental media was quantified by using diffusive gradient in thin films and ultrafiltration. A multibiomarker approach was employed to reveal responses of clams at subindividual and individual levels. The bioaccumulation of Ag was significantly greater at 15 psu versus 30 psu, which could be explained by differences in Ag speciation. In conclusion, the present study showed different impacts of Ag nanomaterial that were not always explained by the release of Ag ions in clams at both salinities; such impacts were particularly characterized by induction of oxidative stress, cell damage, and impairment of energetic levels. Burrowing of clams was affected by the stabilizing agent depending on the salinity tested, with stronger effects at 15 psu. Finally, the present study highlighted salinity-dependent changes in the physiology of estuarine bivalves. Environ Toxicol Chem 2016;35:2550–2561. © 2016 SETAC

La postérité de l’écrivain franco-suisse Robert Pinget (1919-1997) se partage entre différents lieux de mémoire des institutions (bibliothèques, musées, services d’archives, etc.) et des espaces géographiques (Paris et province, pays étrangers). Pinget est un auteur qui a fait carrière en France. Il est né à Genève et, après avoir fait des études de droit pour devenir avocat, est parti à Paris après la Seconde Guerre mondiale pour étudier à l’École nationale supérieure des beaux-arts. N’ayant...

Some sacoglossan sea slugs incorporate intracellular functional algal chloroplasts, a process termed kleptoplasty. “Stolen” chloroplasts (kleptoplasts) can remain photosynthetically active up to several months, contributing to animal nutrition. Whether this contribution occurs by means of translocation of photosynthesis-derived metabolites from functional kleptoplasts to the animal host or by simple digestion of such organelles remains controversial. Imaging of 13C and 15N assimilation over a 12-h incubation period of Elysia viridis sea slugs showed a light-dependent incorporation of carbon and nitrogen, observed first in digestive tubules and followed by a rapid accumulation into chloroplast-free organs. Furthermore, this work revealed the presence of 13C-labeled long-chain fatty acids (FA) typical of marine invertebrates, such as arachidonic (20:4n-6) and adrenic (22:4n-6) acids. The time frame and level of 13C- and 15N-labeling in chloroplast-free organs indicate that photosynthesis-derived primary metabolites were made available to the host through functional kleptoplasts. The presence of specific 13C-labeled long-chain FA, absent from E. viridis algal food, indicates animal based-elongation using kleptoplast-derived FA precursors. Finally, carbon and nitrogen were incorporated in organs and tissues involved in reproductive functions (albumin gland and gonadal follicles), implying a putative role of kleptoplast photosynthesis in the reproductive fitness of the animal host.

Global Natural Product Social Molecular Networking (GNPS) is an interactive online small molecule–focused tandem mass spectrometry (MS2) data curation and analysis infrastructure. It is intended to provide as much chemical insight as possible into an untargeted MS2 dataset and to connect this chemical insight to the user’s underlying biological questions. This can be performed within one liquid chromatography (LC)-MS2 experiment or at the repository scale. GNPS-MassIVE is a public data repository for untargeted MS2 data with sample information (metadata) and annotated MS2 spectra. These publicly accessible data can be annotated and updated with the GNPS infrastructure keeping a continuous record of all changes. This knowledge is disseminated across all public data; it is a living dataset. Molecular networking—one of the main analysis tools used within the GNPS platform—creates a structured data table that reflects the molecular diversity captured in tandem mass spectrometry experiments by computing the relationships of the MS2 spectra as spectral similarity. This protocol provides step-by-step instructions for creating reproducible, high-quality molecular networks. For training purposes, the reader is led through a 90- to 120-min procedure that starts by recalling an example public dataset and its sample information and proceeds to creating and interpreting a molecular network. Each data analysis job can be shared or cloned to disseminate the knowledge gained, thus propagating information that can lead to the discovery of molecules, metabolic pathways, and ecosystem/community interactions. UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones en Productos Naturales (CIPRONA) UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Química

International audience; The domesticated marine microalga Diacronema lutheri is of great interest for producing various highly valuable molecules like lipids, particularly long‐chain polyunsaturated fatty acids (LC‐PUFA). In this study, we investigated the impact of phosphorus (P) and nitrogen (N) starvation on growth, carbon fixation (photosynthetic activity) and partitioning, and membrane lipid remodeling in this alga during batch culture. Our results show that the photosynthetic machinery was similarly affected by P and N stress. Under N starvation, we observed a much lower photosynthetic rate and biomass productivity. The degradation and re‐use of cellular N‐containing compounds contributed to triacylglycerol (TAG) accumulation. On the other hand, P‐starved cells maintained pigment content and a carbon partitioning pattern more similar to the control, ensuring a high biomass. Betaine lipids constitute the major compounds of non‐plastidial membranes, which are rich in eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. Under P and N starvations, EPA was transferred from the recycling of membrane polar lipids, most likely contributing to TAG accumulation.

International audience; Seagrass meadows are monitored in the frame of several environmental programs worldwide, including the Water Framework Directive (WFD), to evaluate the ecological status of European coastal and transitional water bodies. The large size, spatial complexity, and interannual variability of seagrass ecosystems significantly challenge field monitoring. In this study, a multi-mission satellite time-series was used to estimate long-term changes in seagrass status in a macrotidal system dominated by Zostera noltei, at Bourgneuf Bay (French Atlantic coast). Metrics of seagrass extent and density were obtained from Earth Observation (EO) using validated and inter-calibrated Landsat, SPOT and Sentinel2 data from 1985 to 2020. The information provided by satellite data made it possible to compute and compare several seagrass indicators currently in use in several European countries (France, Portugal and UK) within the WFD. Both the seagrass extent and meadow-averaged density displayed increasing trends since 1985. A time-series of merged observations from various satellites revealed a high degree of interannual variability in seagrass extent, with abrupt losses (up to 50% within one year) alternating with periods of slow recovery (typically 4-6 years). The seagrass meadow which was in a moderate status (sensu the WFD) in the 1980s, achieved an overall recurrent good or high status since the mid-1990s. Altogether, the methods and results presented here demonstrated that EO is a reliable source of information for mapping and assessing the status of intertidal seagrass, complementing in situ measurements by providing long-term, spatial view and standardized observation framework. We recommend the systematic use of EO time-series in complement to traditional field measurements in seagrass monitoring programs such as the WFD.

Microalgae, including diatoms, have a high biotechnological potential as efficient producers of high value-added molecules. However, the scientific knowledge of biological processes remains too scarce to make the microalgae-based biotechnology a viable alternative to traditional sources and more research must be carried on to fulfil this insufficiency, especially on the regulation of the stress-triggered carbon reallocation to lipids. In order to bring new elements to the understanding of these mechanisms, a multidisciplinary approach coupling physiological, biochemical and transcriptomic analyses was applied on a highly controlled photobioreactor Phaeodactylum tricornutum culture, shifted from N-replete to N-starvation condition. A special attention to the cell responses was given during the transition between these two nitrogen conditions. The collected information allowed to complement what was already reported in literature in which the two different N conditions are usually compared. The performed experiments showed that the intracellular nitrogen availability acts as a switch-like inducer of metabolic and physiological responses during the transition between a N-repleted and N-starvation equilibria. A major gene expression change is observed when the decreased extracellular N availability forces cells to utilize the intracellular N pools. A reorientation of the cellular metabolism toward an energy storage mode is observed. The central carbon metabolism is overactivated acting as a metabolic flywheel maintaining the energetic equilibrium of the cell. N-requiring activities, including cell division and photosynthetic activity, are affected and gradually reduced. Plastids are partially dismantled but their energetic status is kept in a stand-by mode maintaining the capability of a fast recover after the reintroduction of a nitrogen source.The whole cellular responses are regulated by cellular sensing and signalling mechanisms in which transcription factors play important roles. Differential gene expression is observed in several transcription factors encoding genes. For this reason, transcription factors candidates have been selected for the generation of overexpressing, silencing and/or knock out mutant lines. A large number of transformant lines were generated requiring an efficient large scale screening method. In this frame, a vibrational spectroscopy-based technique was set up, allowing a fast biochemical characterization and replacing time consuming and tedious conventional biochemical analyses. Additionally, a microtiter-plate-based cultivation protocol was set up allowing the management of a large number of small volume culture. To optimize small volume culturing, a self-built device was designed, assembled and tested showing a potential for microalgal cultivation in microtiter plates.To summarize, this PhD work contributes to the comprehension of the cellular processes involved in the response to nitrogen limitation and on the control mechanisms in diatoms. It provides new insights on the potential application and optimization of microalgae as competitive source of bio-commodities.; Les microalgues, dont les diatomées, ont un potentiel biotechnologique élevé en tant que productrices efficaces de molécules à haute valeur ajoutée, généralement en condition de stress. Cependant, la connaissance scientifique des processus biologiques reste trop limitée pour faire de biotechnologies à base de microalgues une alternative viable aux sources traditionnelles. Un travail de recherche doit être mené pour combler cette insuffisance, notamment sur la régulation de la réallocation du carbone déclenchée par le stress vers les lipides. Afin d'apporter de nouveaux éléments à la compréhension de ces mécanismes, une approche multidisciplinaire couplant des analyses physiologiques, biochimiques et transcriptomiques a été utilisée sur une culture de Phaeodactylum tricornutum soumise à une carence en azote progressive. Cette expérience a été effectuée en conditions de culture très contrôlées dans un photobioréacteur. Une attention particulière a été portée aux réponses cellulaires mise en place lors de la transition entre les deux conditions azotées. Les informations recueillies ont permis de compléter le connaissances actuelles, établies par comparaison de différentes conditions de disponibilité en azote. Les résultats montrent que la disponibilité de l'azote intracellulaire agit comme un interrupteur de réponses métaboliques et physiologiques au cours de la transition entre deux conditions d’équilibre : la présence d’une quantité suffisant d’azote et son absence. Un changement majeur d'expression génique est observé lorsque la réduction de disponibilité en azote extracellulaire force les cellules à utiliser les réserves d’azote intracellulaires. Une réorientation du métabolisme cellulaire vers un stockage d'énergie est observée. Le métabolisme central du carbone est suractivé, maintenant l'équilibre énergétique de la cellule. Les activités cellulaires qui nécessitent de l’azote, y compris la division cellulaire et l'activité photosynthétique, sont affectées et progressivement réduites. Les plastes sont partiellement démantelés mais leur état énergétique est maintenu en mode veille qui permet une récupération rapide après la réintroduction d'une source d'azote. Les réponses cellulaires entières sont régulées par des mécanismes de détection et de signalisation cellulaires dans lesquels les facteurs de transcription jouent un rôle très important. L'expression différentielle des gènes est observée sur plusieurs gènes codants des facteurs de transcription. Des facteurs de transcription candidats ont ainsi été sélectionnés afin de générer des lignées mutantes sur-exprimant, sous-exprimant ou éliminant le gène codant. Un grand nombre de lignées transformantes ont été générées, nécessitant une méthode de criblage à grande échelle efficace. Dans ce cadre, une technique basée sur la spectroscopie vibrationnelle a été mise en place, permettant une caractérisation biochimique rapide et remplaçant les analyses biochimiques conventionnelles longues et fastidieuses. De plus, un protocole de culture en microplaques a été mis en place permettant la gestion d'un grand nombre de culture en petit volume. Pour optimiser ces cultures, un dispositif a été conçu, assemblé et testé. En résumé, ce travail de thèse contribue à la compréhension des processus cellulaires impliqués dans la réponse à la limitation azotée et sur les mécanismes de contrôle chez les diatomées. Il fournit de nouvelles informations sur l'application potentielle et l'optimisation des microalgues en tant que source compétitive de produits d’origine naturelle.

International audience; This work investigates the potential probiotic effect of ma rennine-a natural pigme nt produ ced by the diatom Haslea ostrearia-on Vibrio splendidus. These ma rine bacteria are often considered a threat for aquacu lture; therefore, ch em ical antibiotics can be required to redu ce bacterial outbreaks. In vi vo 2 H solid-state NMR was used to probe the effects of ma rennine on the bacterial me mbrane in the exponential and stationary ph ases. Comparisons were ma de with polymyxin B (PxB)-an antibiotic used in aquacu lture and known to interact with Gram (−) bacteria me mbranes. We also investigated the effect of ma rennine using 31 P solidstate NMR on model me mbranes. Our results show that ma rennine has little effect on ph osph olipid headgroups dynamics, bu t redu ces the acyl ch ain fluidity. Our data suggest that the two antimicrobial agents perturb V. splendidus me mbranes through different me ch anism s. While PxB would alter the bacterial outer and inner me mbranes, ma rennine would act through a me mbrane stiffening me ch anism , without affecting the bilayer integrity. Our stud y proposes this microalgal pigme nt, wh ich is harm less for hu ma ns, as a potential treatme nt against vibriosis.

International audience

International audience

Foraminifera are ubiquitously distributed in marine habitats, playing a major role in marine sediment carbon sequestration and the nitrogen cycle. They exhibit a wide diversity of feeding and behavioural strategies (heterotrophy, autotrophy and mixotrophy), including species with the ability of sequestering intact functional chloroplasts from their microalgal food source (kleptoplastidy), resulting in a mixotrophic lifestyle. The mechanisms by which kleptoplasts are integrated and kept functional inside foraminiferal cytosol are poorly known. In our study, we investigated relationships between feeding strategies, kleptoplast spatial distribution and photosynthetic functionality in two shallow-water benthic foraminifera (Haynesina germanica and Elphidium williamsoni), both species feeding on benthic diatoms. We used a combination of observations of foraminiferal feeding behaviour, test morphology, cytological TEM-based observations and HPLC pigment analysis, with non-destructive, single-cell level imaging of kleptoplast spatial distribution and PSII quantum efficiency. The two species showed different feeding strategies, with H. germanica removing diatom content at the foraminifer’s apertural region and E. williamsoni on the dorsal site. All E. williamsoni parameters showed that this species has higher autotrophic capacity albeit both feeding on benthic diatoms. This might represent two different stages in the evolutionary process of establishing a permanent symbiotic relationship, or may reflect different trophic strategies.

In recent years diatoms have emerged as a major algal source for the production of bioactive compounds. Marine diatoms grow quickly and can store high amount of lipids. Unfortunately, they are little studied and underexploited resources. The current work deals with an original and rarely investigated source of diatoms: intertidal mudflats. It aims to evaluate the lipid production potential of some strains of benthic diatom species, isolated and hosted in the Nantes Culture Collection (NCC) when cultivated in an airlift photobioreactor. Six strains known for their high biomass and/or lipid productivity: Amphora sp. (NCC169), Entomoneis paludosa (NCC18.2), Nitzschia alexandrina (NCC33), Nitzschia sp. (NCC109), Opephora sp. (NCC366), and Staurosira sp. (NCC182) were cultivated in airlift photobioreactors for the first time. Their lipid class composition, fatty acid, and sterol distribution were studied. Total lipid production varied from 11.4 (Amphora sp.) to 41%DW (Staurosira sp.). Neutral lipid amounts varied from 23 (Amphora sp.) to 76% (Staurosira sp.) of total lipids (%TL). Glycolipids ranged from 18 (Staurosira sp.) to 59%TL (Opephora sp.) and phospholipids accounted for 6 (Staurosira sp.) to 26%TL (Amphora sp.). Some qualitative and quantitative differences were identified in both fatty acid and sterol composition in the different strains analyzed. Staurosira sp. seems to be the most promising species in terms of lipid production and most particularly in triacylglycerol production. Entomoneis paludosa produced phytosterols and eicosapentaenoic acid (EPA), compounds with potential for application in the pharmaceutical sector. Nitzschia alexandrina produced squalene and low levels of saturated fatty acids which could both be interesting in the nutraceutical industry as antioxidants.

International audience; Homologous recombination (HR) is involved in repairing DNA double-strand breaks (DSB), the most harmful for the cell. Regulating HR is essential for maintaining genomic stability. In many forms of cancer, overactivation of HR increases tumor resistance to DNA-damaging treatments. RAD51, HR's core protein, is very often over- expressed in these cancers and plays a critical role in cancer cell development and survival. Targeting RAD51 directly to reduce its activity and its expression is therefore one strategy to sensitize and overcome resistance cancer cells to existing DNA-damaging therapies which remains the limiting factor for the success of targeted therapy.This review describes the structure and biological roles of RAD51, summarizes the different targeted sites of RAD51 and its inhibitory compounds discovered and described in the last decade.

Assessments based on monetary valuation of ecosystem services have been increasingly used as a tool to highlight the connection between ecosystems and society. The dissemination of this approach is leading to difficulties and ambiguities related to the use of such assessments in the socio-political realm. Such limits can be stressed using the case study of intertidal bare mudflats. These coastal habitats indeed provide many ecological functions—several being related to the high production of benthic microalgae—but also remain poorly known for some other aspects. The major users of these habitats (i.e. oyster farmers) are still unaware about the trophic role of benthic microalgae, limiting contingent valuation survey methods. Moreover, economic valuation cannot take into account the potentials of mudflats (i.e. undescribed functions) like positive feedbacks related to shellfish farming and provision of bioactive compounds. The lack of physical boundaries in marine systems also strongly reduces the effectiveness of assessments. Lastly, there are concerns that monetary valuation can lead to a commodification of the nature or to the economization of the environment (e.g. appropriation of the environment by users, creation of artificial thresholds). The evaluation of the functions of a socio-ecosystem should not only be restricted to a monetary assessment of its ecosystem services, as this framework may be more reductive than integrative. Some other descriptors—not based on currencies—should be used for ecosystem description.

International audience; The rapid innovations in metabolite profiling, bioassays and chemometrics have led to a paradigm shift in natural product (NP) research. Indeed, having partial or full structure information about possibly “all” specialized metabolites and an estimation of their levels in plants or microorganisms provides a way to perform pharmacognostic or chemical ecology investigations from a new and holistic perspective. The increasing amount of accurate metabolome data that can be acquired on massive sample sets, notably through data-dependent LC-HRMS/MS and NMR profiling, allows the mapping of natural extracts at an unprecedented level of precision.Most progress made recently in accelerating metabolite identification has been pushed by the need for metabolomics to have tools that provide a confident annotation of the biomarkers highlighted as the results of data mining through multivariate analysis, often on important datasets of complexsamples. Historically, NP chemists have been involved in the unambiguous full de novo identification of unknown compoundsfrom complex natural biological matrices. This process is classically performed by the tedious isolation of pure bioactive NPs through comprehensive bioactivity-guided isolation workflows involving orthogonal chromatographic steps at the preparative level. Increasingly advanced metabolomics metabolite profiling methods are of strategic importance in dereplication workflows in NP research as well as for the full metabolome composition assignment of relevant organisms from both drug discovery and chemical ecology perspectives.In this review, we describe the latest developments in metabolite profiling by both LC-MS and NMRbased methods and related databases from a natural product chemist perspective. We assess the current possibilities and limits of such methods and the workflows for manual and automated NPannotations by equally treating the MS and NMR approaches that are both key for the “as confident as possible” NP annotation in crude natural extracts. We also propose future lines of development in the field that are important for NP research but are also generally needed for metabolite annotation in metabolomics because NPs represent perfect candidate compounds for identification due to their intrinsic structural complexity and chemodiversity across organisms. This review does not aim to provide a comprehensive survey of all metabolite profiling applications made in NP research to date. Typical case studies are discussed, and an update of a selection of the latest advanced original studies and numerous specialized reviews is made with links to tools and DBs regarded as useful for their current or future usage in NP research. Evaluations of what can be readily implemented and what is still required for confident NP structural elucidation are made, especially concerning access to generic structural and spectral DBs as well as the use of orthogonal detection methods for improved confidence in metabolite annotation.

Microphytobenthos (MPB) is composed of unicellular photosynthetic organisms that colonize intertidal sediments within the first millimeters of the photic zone and form biofilms at low tide. In estuaries, this benthic group can represent the main primary producer and deliver several ecosystem services. However, it is not currently used as a bioindicator of water quality, contrary to the widespread use of phytobenthos in freshwater settings. This study assesses the potential of developing MBP metrics to assess water quality in transitional waters using Sentinel-2 (S2) satellite imagery. A Random Forest machine learning classification was used to distinguish different types of intertidal vegetation in 26 French estuaries and bays, in particular MPB and green macroalgae (chlorophytes), using multispectral indices. High accuracy was generally achieved for the identification of MPB when compared with field validation data, for both User’s and Producer’s accuracies, which corresponded to 94% and 84% respectively. Two Earth observation variables were retrieved: the Normalized Difference Vegetation Index (NDVI), a proxy of MPB biomass, and MPB percent cover integrated over the entire intertidal area of the water body. From a total of 918 S2 images from over a full year, 28% were exploitable due to the combined requirements of cloud-free pixels collected during low tide. With its 10 m spatial resolution, S2 was able to map all estuaries. MPB percent cover showed a stronger gradient between estuaries than MPB NDVI. MPB percent cover was also significantly correlated with green macroalgae percent cover, and a group of estuaries characterized by the highest MPB and green macroalgae coverage corresponded to eutrophic sites impacted by intensive farming activities. A multivariate analysis confirmed that MPB percent cover was indeed related to nutrients. It was also related to sediment type which was one of the main factors underlying differences between estuaries. This work is a first step toward a water quality metric using MPB, and several recommendations are proposed to refine this approach. Sentinel-2 imagery, which is publicly available, presents an interesting compromise to map estuarine microphytobenthos in order to assess the ecological status of transitional waters.

International audience; In the course of investigations on peptaibol chemodiversity from marine-derived Trichoderma spp., five new 15-residue peptaibols named pentadecaibins I–V (1–5) were isolated from the solid culture of the strain Trichoderma sp. MMS1255 belonging to the T. harzianum species complex. Phylogenetic analyses allowed precise positioning of the strain close to T. lentiforme lineage inside the Harzianum clade. Peptaibol sequences were elucidated on the basis of their MS/MS fragmentation and extensive 2D NMR experiments. Amino acid configurations were determined by Marfey’s analyses. The pentadecaibins are based on the sequences Ac-Aib1-Gly2-Ala3-Leu4-Aib/Iva5-Gln6-Aib/Iva7-Val/Leu8-Aib9-Ala10-Aib11-Aib12-Aib13-Gln14-Pheol15. Characteristic of the pentadecaibin sequences is the lack of the Aib-Pro motif commonly present in peptaibols produced by Trichoderma spp. Genome sequencing of Trichoderma sp. MMS1255 allowed the detection of a 15-module NRPS-encoding gene closely associated with pentadecaibin biosynthesis. Pentadecaibins were assessed for their potential antiproliferative and antimicrobial activities.

Long-chain polyunsaturated fatty acids n-3 series and especially docosahexaenoic acid are known to exert preventive effects on metabolic disturbances associated with obesity and decrease cardiovascular disease risk. n-3 LC-PUFAs are mainly consumed in the form of fish oil, while other sources, such as certain microalgae, may contain a high content of these fatty acids. The aim of this study was to evaluate the effects of Tisochrysis lutea (Tiso), a microalga rich in DHA, on metabolic disorders associated with obesity. Three male Wistar rat groups were submitted for eight weeks to a standard diet or high-fat and high fructose diet (HF), supplemented or not with 12% of T. lutea (HF-Tiso). The supplementation did not affect plasma alanine aminotransferase (ALAT). Bodyweight, glycemia and insulinemia decreased in HF-Tiso rats (ANOVA, p &lt, 0.001), while total plasma cholesterol, high-density lipoprotein-cholesterol (HDL-C) increased (ANOVA, p &lt, 0.001) without change of low-density lipoprotein-cholesterol (LDL-C) and triacylglycerol (TAG) levels. Tiso supplementation decreased fat mass and leptinemia as well as liver TAG, cholesterol and plasma tumor necrosis factor-alpha levels (ANOVA, p &lt, 0.001) while it did not affect interleukin 6 (IL-6), IL-4 and lipopolysaccharides levels. HF-Tiso rats showed an increase of IL-10 level in abdominal adipose tissue (ANOVA, p &lt, 0.001). In conclusion, these results indicated that DHA-rich T. lutea might be beneficial for the prevention of obesity and improvement of lipid and glucose metabolism.

International audience; Long-chain polyunsaturated fatty acids n-3 series and especially docosahexaenoic acid are known to exert preventive effects on metabolic disturbances associated with obesity and decrease cardiovascular disease risk. n-3 LC-PUFAs are mainly consumed in the form of fish oil, while other sources, such as certain microalgae, may contain a high content of these fatty acids. The aim of this study was to evaluate the effects of Tisochrysis lutea (Tiso), a microalga rich in DHA, on metabolic disorders associated with obesity. Three male Wistar rat groups were submitted for eight weeks to a standard diet or high-fat and high fructose diet (HF), supplemented or not with 12% of T. lutea (HF-Tiso). The supplementation did not affect plasma alanine aminotransferase (ALAT). Bodyweight, glycemia and insulinemia decreased in HF-Tiso rats (ANOVA, p < 0.001), while total plasma cholesterol, high-density lipoprotein-cholesterol (HDL-C) increased (ANOVA, p < 0.001) without change of low-density lipoprotein-cholesterol (LDL-C) and triacylglycerol (TAG) levels. Tiso supplementation decreased fat mass and leptinemia as well as liver TAG, cholesterol and plasma tumor necrosis factor-alpha levels (ANOVA, p < 0.001) while it did not affect interleukin 6 (IL-6), IL-4 and lipopolysaccharides levels. HF-Tiso rats showed an increase of IL-10 level in abdominal adipose tissue (ANOVA, p < 0.001). In conclusion, these results indicated that DHA-rich T. lutea might be beneficial for the prevention of obesity and improvement of lipid and glucose metabolism.

International audience; Cyanobacteria (blue-green microalgae) are ubiquitous, Gram-negative photoautotrophic prokaryotes. They are considered as one of the most efficient sources of bioactive secondary metabo- lites. More than 50% of cyanobacteria are cultivated on commercial platforms to extract bioactive compounds, which have bene shown to possess anticancer activity. The chemically diverse natural compounds or their analogues induce cytotoxicity and potentially kill a variety of cancer cells via the induction of apoptosis, or altering the activation of cell signaling, involving especially the protein kinase-C family members, cell cycle arrest, mitochondrial dysfunctions and oxidative damage. These therapeutic properties enable their use in the pharma and healthcare sectors for the betterment of future generations. This review provides a baseline overview of the anti-cancerous cyanobacterial bioactive compounds, along with recently introduced nanomaterials that could be used for the development of new anticancer drugs to build a healthy future for mankind.

Oxygen and nitrate availabilities impact the marine nitrogen cycle at a range of spatial and temporal scales. Here, we demonstrate the impact of denitrifying foraminifera on the nitrogen cycle at two oxygen and nitrate contrasting stations in a fjord environment (Gullmar Fjord, Sweden). Denitrification by benthic foraminifera was determined through the combination of specific density counting per microhabitat and specific nitrate respiration rates obtained through incubation experiments using N2O microsensors. Benthic nitrate removal was calculated from submillimeter chemical gradients extracted from 2D porewater images of the porewater nitrate concentration. These were acquired by combining the DET technique (diffusive equilibrium in thin film) with chemical colorimetry and hyperspectral imagery. Sediments with high nitrate concentrations in the porewater and oxygenated overlying water were dominated by the non-indigenous species (NIS) Nonionella sp. T1. Denitrification by this species could account for 50 %–100 % of the nitrate loss estimated from the nitrate gradients. In contrast sediments below hypoxic bottom waters had low inventories of porewater nitrate, and denitrifying foraminifera were rare. Their contribution to benthic nitrate removal was negligible (< 5 %). Our study showed that benthic foraminifera can be a major contributor to nitrogen mitigation in oxic coastal ecosystems and should be included in ecological and diagenetic models aiming to understand biogeochemical cycles coupled to nitrogen.

Our study aimed to evaluate the effect of trace element pollution in the polychaete Perinereis cultrifera (Grube, 1840) from two Tunisian coasts (the port of Rades, S1; and the Punic port of Carthage, S2). To this end, we used an approach based on proximate composition, biomarker responses and trace element bioaccumulation. Our results showed a decreasing order of metals concentrations (Zn>Cu>Cd>Pb) in P. cultrifera from S1 and S2. The accumulation of Cd, Cu and Zn was significantly higher in S1 than in S2, especially in summer. Lipid, protein and glycogen content also changed significantly between S1 and S2 in relation to trace metal accumulation and environmental conditions. The results revealed a higher level of thiobarbituric acid in P. cultrifera from S1 than from S2. In addition, the enzymatic and non-enzymatic antioxidant defence system (catalase, glutathione-S-transferase, superoxide dismutase, glutathione and metallothionein) was enhanced and acetylcholinesterase activities decreased in P. cultrifera in S1 in comparison with S2. A principal component analysis showed that P. cultrifera from S1 exhibited a clear disruption of oxidative stress responses and trace element bioaccumulation among seasons. Overall, these findings revealed the sensitivity of those organisms to environmental conditions., Nuestro estudio tenía como objetivo evaluar el efecto de la contaminación por elementos traza en el poliqueto Perinereis cultrifera (Grube, 1840) de dos costas tunecinas (S1: el puerto de Rades; S2: el puerto púnico de Cartago). Para ello, hemos utilizado un enfoque basado en la composición proximal, las respuestas de los biomarcadores y la bioacumulación de elementos traza. Nuestros resultados mostraron un orden decreciente de las concentraciones de metales (Zn>Cu>Cd>Pb) en P. cultrifera de S1 y S2. Nuestros datos mostraron una acumulación significativa de Cd, Cu y Zn en P. cultrifera recolectada en el puerto de Rades (S1), especialmente durante la temporada de verano, en comparación con las del puerto púnico de Cartago (S2). Asimismo, los contenidos de lípidos, proteínas y glicógenos cambiaron significativamente entre S1 y S2 en relación con la acumulación de metales y las condiciones ambientales. Los resultados obtenidos revelaron un aumento del nivel de ácido barbitúrico (TBARS) en P. cultrifera de S1 en comparación con S2. Además, se observó un aumento significativo del sistema de defensa antioxidante enzimático y no enzimático (catalasa CAT, glutación-S-transferasa: GST, superóxido dismutasa: SOD, glutatión: GSH y metaloproteína: MT) y una disminución de las actividades de la acetilcolinesterasa (AChE) se observaron en P. cultrifera del puerto de Rades (S1) en comparación con las del puerto púnico de Cartago (S2). El análisis de componentes principales (PCA) mostró que la P. cultrifera de S1 presentaba una clara alteración de las respuestas al estrés oxidativo y la bioacumulación de elementos traza entre las estaciones. En general, estos resultados revelaron la sensibilidad de estos organismos frente a las condiciones ambientales

The whitefly, Bemisia tabaci is a hemipteran pest of vegetable crops vectoring a broad category of viruses. Currently, this insect pest showed a high adaptability and resistance to almost all the chemical compounds commonly used for its control. In many cases, transposable elements (TEs) contributed to the evolution of host genomic plasticity. This study focuses on the annotation of Mariner-like elements (MLEs) and their derived Miniature Inverted repeat Transposable Elements (MITEs) in the genome of B. tabaci. Two full-length MLEs belonging to mauritiana and irritans subfamilies were detected and named Btmar1.1 and Btmar2.1, respectively. Additionally, 548 defective MLE sequences clustering mainly into 19 different Mariner lineages of mauritiana and irritans subfamilies were identified. Each subfamily showed a significant variation in MLE copy number and size. Furthermore, 71 MITEs were identified as MLEs derivatives that could be mobilized via the potentially active transposases encoded by Btmar 1.1 and Btmar2.1. The vast majority of sequences detected in the whitefly genome present unusual terminal inverted repeats (TIRs) of up to 400 bp in length. However, some exceptions are sequences without TIRs. This feature of the MLEs and their derived MITEs in B. tabaci genome that distinguishes them from all the other MLEs so far described in insects, which have TIRs size ranging from 20 to 40 bp. Overall, our study provides an overview of MLEs, especially those with large TIRs, and their related MITEs, as well as diversity of their families, which will provide a better understanding of the evolution and adaptation of the whitefly genome.

International audience; Algae are organisms with an enormous biodiversity and contain manifold fatty acid molecular structures and ratios. This chapter presents information about the structure and distribution of fatty acids in algae whether microalgae or macroalgae. The parameters affecting lipid and fatty acid contents as well as distribution are also discussed. Methods for isolation and purification of fatty acids from algae to obtain highly pure fatty acid or fatty acid fractions with good overall yields are presented. Algal fatty acids are known as sources of bioactive compounds for health promotion and wellness. Lipid fractions and fatty acids act as actives or additives for cosmeceutical applications. For health promotion, preventive effects of n-3 polyunsaturated fatty acids on cardiovascular disease, metabolic syndrome and cancer are discussed. The role of n-3 fatty acids in cancer therapy and antiviral activities of lipids are also exposed. Furthermore, potential commercial application domains and concepts are discussed in this chapter.

International audience

Place: Hoboken Publisher: Wiley WOS:000556059500001; International audience; The aim of this study was to summarise the literature reporting the risk factors for mortality in the mussel speciesMytilus edulisandMytilus galloprovincialisin order to identify potential science-based solutions to prevent or mitigate mussel mortality outbreaks. We followed the PRISMA methodology: Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The studied corpus of 91 publications (114 studies) was highly heterogeneous with respect to the methodological approaches used to define or estimate mussel mortality and the related putative risk factors. Results showed that the mortality risk of both mussel speciesM. edulisandM. galloprovincialisvaried across the seasons, increased with an elevated seawater temperature above a thermal threshold of 20 and 24 degrees C, respectively, decreased by protecting mussels from predation, and was associated with the presence of pathogens inM. edulis. ForM. galloprovincialis, using mussel spat from the same area where the farming is carried out and farming them together with another mussel species appears to reduce the mortality risk. However, forM. edulis, this could be achieved by using pure crosses and in particular mussel spat having a selected genotype. For wild bed conservation, sand accumulation and anthropogenic sedimentation should be minimised. Our analysis showed that current approaches to this research topic are limited and are unlikely to yield actionable evidence to identify mussel mortality prevention or mitigation strategies. Therefore, recommendations are offered to increase the ability of future eco-epidemiological research to identify multiple exposures associated with mussel mortality, underpinned by standardised efforts and cooperative initiatives.

The cotton bollworm Helicoverpa armigera H&uuml, bner (Lepidoptera: Noctuidae) is an important pest of many crops that has developed resistance to almost all groups of insecticides used for its management. Insecticide resistance was often related to Transposable Element (TE) insertions near specific genes. In the present study, we deeply retrieve and annotate TEs in the H. armigera genome using the Pipeline to Retrieve and Annotate Transposable Elements, PiRATE. The results have shown that the TE library consists of 8521 sequences representing 236,132 TE copies, including 3133 Full-Length Copies (FLC), covering 12.86% of the H. armigera genome. These TEs were classified as 46.71% Class I and 53.29% Class II elements. Among Class I elements, Short and Long Interspersed Nuclear Elements (SINEs and LINEs) are the main families, representing 21.13% and 19.49% of the total TEs, respectively. Long Terminal Repeat (LTR) and Dictyostelium transposable element (DIRS) are less represented, with 5.55% and 0.53%, respectively. Class II elements are mainly Miniature Inverted Transposable Elements (MITEs) (49.11%), then Terminal Inverted Repeats (TIRs) (4.09%). Superfamilies of Class II elements, i.e., Transib, P elements, CACTA, Mutator, PIF-harbinger, Helitron, Maverick, Crypton and Merlin, were less represented, accounting for only 1.96% of total TEs. In addition, we highlighted TE insertions in insecticide resistance genes and we successfully identified nine TE insertions belonging to RTE, R2, CACTA, Mariner and hAT superfamilies. These insertions are hosted in genes encoding cytochrome P450 (CyP450), glutathione S-transferase (GST), and ATP-binding cassette (ABC) transporter belonging to the G and C1 family members. These insertions could therefore be involved in insecticide resistance observed in this pest.

International audience; Fucoxanthin is a well-known carotenoid of the xanthophyll family, mainly produced by marine organisms such as the macroalgae of the fucus genus or microalgae such as Phaeodactylum tricornutum. Fucoxanthin has antioxidant and anti-inflammatory properties but also several anticancer effects. Fucoxanthin induces cell growth arrest, apoptosis, and/or autophagy in several cancer cell lines as well as in animal models of cancer. Fucoxanthin treatment leads to the inhibition of metastasis-related migration, invasion, epithelial-mesenchymal transition, and angiogenesis. Fucoxanthin also affects the DNA repair pathways, which could be involved in the resistance phenotype of tumor cells. Moreover, combined treatments of fucoxanthin, or its metabolite fucoxanthinol, with usual anticancer treatments can support conventional therapeutic strategies by reducing drug resistance. This review focuses on the current knowledge of fucoxanthin with its potential anticancer properties, showing that fucoxanthin could be a promising compound for cancer therapy by acting on most of the classical hallmarks of tumor cells.

RATIONALE The dinoflagellate genera Gambierdiscus and Fukuyoa are producers of toxins responsible for Ciguatera Poisoning (CP). Although having very low oral potency, maitotoxins (MTXs) are very toxic following intraperitoneal injection and feeding studies have shown they may accumulate in fish muscle. To date, six MTX congeners have been described but two congeners (MTX2 and MTX4) have not yet been structurally elucidated. The aim of the present study was to further characterize MTX4. METHODS Chemical analysis was performed using liquid chromatography coupled to a diode-array detector (DAD) and positive ion mode high-resolution mass spectrometry (LC/HRMS) on partially purified extracts of G. excentricus (strain VGO792). HRMS/MS studies were also carried out to tentatively explain the fragmentation pathways of MTX and MTX4. RESULTS The comparison of UV and HRMS (ESI+ ) spectra between MTX and MTX4 led us to propose the elemental formula of MTX4 (C157 H241 NO68 S2 , as the unsalted molecule). The comparison of the theoretical and measured m/z values of the doubly charged ions of the isotopic profile in ESI+ were coherent with the proposed elemental formula of MTX4. The study of HRMS/MS spectra on the tri-ammoniated adduct ([M - H + 3NH4 ]2+ ) of both molecules gave additional information about structural features. The cleavage observed, probably located at C99 -C100 in both MTX and MTX4, highlighted the same A-side product ion shared by the two molecules. CONCLUSIONS All these investigations on the characterization of MTX4 contribute to highlighting that MTX4 belongs to the same structural family of MTXs. However, to accomplish a complete structural elucidation of MTX4, an NMR-based study and LC/HRMSn investigation will have to be carried out.

The implementation of Safe(r) by Design (SbD) in industrial innovations requires an integrated approach where the human, environmental and economic impact of the SbD measures is evaluated across and throughout the nanomaterial (NM) life cycle. SbD was implemented in six industrial companies where SbD measures were applied to NMs, nano-enabled products (NEPs) and NM/NEP manufacturing processes. The approach considers human and environmental risks, functionality of the NM/NEP and costs as early as possible in the innovation process, continuing throughout the innovation progresses. Based on the results of the evaluation, a decision has to be made on whether to continue, stop or re-design the NM/NEP/process or to carry out further tests/obtain further data in cases where the uncertainty of the human and environmental risks is too large. However, SbD can also be implemented at later stages when there is already a prototype product or process available, as demonstrated in some of the cases. The SbD measures implemented in some of the case studies did not result in a viable solution. For example the coating of silicon nanoparticles with amorphous carbon increased the conductivity, the stability and reduced the dustiness of the particles and therefore the risk of explosion and the exposure to workers. However the socioeconomic assessment for their use in lithium-ion batteries for cars, when compared to the use of graphite, showed that the increase in performance did not overcome the higher production costs. This work illustrates the complexities of selecting the most appropriate SbD measures and highlights that SbD cannot be solely based on a hazard and exposure assessment but must include other impacts that any SbD measures may have on sustainability including energy consumption and waste generation as well as all associated monetary costs.

International audience; Microphytobenthos (MPB) at the sediment surface of intertidal mudflats are known to show a high spatial and temporal variability in response to the biotic and abiotic conditions prevailing at the mud surface. It makes long-term and large-scale monitoring of MPB Gross Primary Production (GPP) difficult to set up. In this study, we developed the first 3D physical-biological coupled model (MARS-3D) that explicitly simulates GPP of intertidal MPB at the mudflat scale, and we compared the outputs with in situ and space remote sensing MPB GPP data. We discuss the sources of discrepancies between the modeling and the remote sensing approach in the light of future developments to be done. For instance, the remote sensing algorithm provides a very synoptic view of the mudflat GPP. It is well-suited to achieve diagnostic estimates of MPB GPP at the synoptic spatial and temporal scale. By contrast, the MARS-3D model provides a more dynamic representation of the MPB activity and prognostic estimates of MPB GPP over the mudflat. It is very relevant to resolve the seasonal and inter-annual dynamics of MPB. Getting comparable GPP estimates derived from the remote sensing algorithm and 3D physical-biological coupled model will further require a better convergence in terms of equations structure, biological constants parameterization, and source data used (i.e., vegetation index vs. chlorophyll a). Setting a common parameterization in both the numerical model and remote sensing algorithm might be challenging in a perspective of mapping MPB PP over large mudflats from a synoptic to inter-annual time scale, but it could open the door to a new way of quantifying MPB GPP over large intertidal mudflats.

Rationale In the field of natural products, de-replication of complex mixtures has become a usual practice to annotate known compounds and avoid their re-isolation. For this purpose, many groups rely on liquid chromatography coupled to high-resolution mass spectrometry (HPLC/MS) to deduce molecular formulae of compounds allowing comparison with public or in-house databases. Electrospray ionization (ESI) is usually considered as the method of choice for investigating a large panel of compounds but, in some cases, it may lead to unusual results as described in this article for ergosterol. Methods Ergosterol and other fungal sterols in methanolic solution were analysed using various chromatographic gradients with HPLC/MS using both ion trap time-of-flight MS and Orbitrap MS instruments fitted with an ESI source. Further flow injection analyses were performed to investigate the influence of the solvent composition. MS/MS fragmentation data were acquired to annotate the various ions observed. Results Contrary to other fungal sterols, ergosterol was found to be highly sensitive to oxidation during ESI. Putative structures were proposed based on MS/MS studies and known oxidation mechanisms of ergosterol by reactive oxygen species that could be formed in the ESI process. The proportion of acetonitrile in the eluent was found to influence this in-source oxidation, with an increased proportion of oxidized sodium adducts with higher proportions of acetonitrile. Conclusions While ergosterol is a major sterol found in fungi, this study investigates its ionization by electrospray for the first time. The results reported here will help further detection and annotation of this compound in fungal extracts after HPLC/ESI-MS analyses.

Large-scale production of microalgae is mainly carried out in solar cultures. Under these conditions, cells experience various light fluctuation dynamics that is mostly due to day/night cycles, weather conditions, cell displacement between the light surface and the near-dark bottom of the culture, or regular passage through the design dark fractions of the photobioreactor (PBR). In response to these light variations, microalgae developed response mechanisms. In the short term, they protect themselves from supersaturating light intensity for example by dissipating excess energy as heat. In the long term they change their pigment content to use light energy with the greatest efficiency. This study aims at understanding and optimizing the photosynthetic conversion of light energy by Chlorella vulgaris in solar PBR. For this purpose, experiments under controlled conditions were carried out at the laboratory scale. At the cell level, transient behaviours were observed, particularly in the presence of supersaturating light. Photoacclimation impacted photoprotection and photoinhibition mechanisms of the cells. At the reactor scale, characteristic times of photosynthetic responses were explored during increasing or decreasing light step transitions. Subsequently, an in vivo chlorophyll a fluorescence measurement sensor was implemented online on a PBR and its usefulness was studied for monitoring solar cultures, particularly for maintaining good culture conditions and estimating productivity. In addition, this probe supplemented by gas flux measurements also made it possible to measure the impact of PBR dark fractions on the photosynthetic response of C. vulgaris.; La production à grande échelle de micro-algues est principalement réalisée en cultures solaires. Dans ces conditions, les cellules subissent de nombreuses variations de lumière à cause des cycles jour/nuit, de la météo, de leur déplacement entre la surface éclairée et le fond sombre de la culture ou de leur passage régulier dans des parties non éclairées du photobioréacteur (PBR). En réponse à ces variations, les micro-algues ont développé des mécanismes leur permettant de se protéger à court terme contre de trop fortes intensités lumineuses, par exemple en dissipant l’énergie excédentaire sous forme de chaleur, et à long terme d’utiliser l’énergie lumineuse avec la meilleure efficacité en modifiant leur teneur en pigments. Cette étude porte sur la compréhension et l’optimisation de la conversion photosynthétique de l’énergie lumineuse par Chlorella vulgaris en PBR solaire. Pour cela des expériences en conditions contrôlées ont été réalisées à l’échelle du laboratoire. Au niveau de la cellule, des comportements transitoires ont pu être observés notamment en présence de lumière sursaturante. La photoacclimatation impacte les mécanismes de photoprotection et de photoinhibition des cellules. A l’échelle du PBR, les temps caractéristiques des réponses photosynthétiques de la culture ont été explorés lors de transitions lumineuses ascendantes ou descendantes. Par la suite, une sonde de mesure de la fluorescence de la chlorophylle a a été implémentée en ligne sur un PBR et son utilité a été étudiée pour le suivi de cultures solaires notamment pour le maintien de conditions favorables et l’estimation de la productivité. De plus, cette sonde a également permis de mesurer l’impact des boucles sombres sur la réponse photosynthétique de C. vulgaris grâce à des mesures complémentaires de flux de gaz.

Large-scale production of microalgae is mainly carried out in solar cultures. Under these conditions, cells experience various light fluctuation dynamics that is mostly due to day/night cycles, weather conditions, cell displacement between the light surface and the near-dark bottom of the culture, or regular passage through the design dark fractions of the photobioreactor (PBR). In response to these light variations, microalgae developed response mechanisms. In the short term, they protect themselves from supersaturating light intensity for example by dissipating excess energy as heat. In the long term they change their pigment content to use light energy with the greatest efficiency. This study aims at understanding and optimizing the photosynthetic conversion of light energy by Chlorella vulgaris in solar PBR. For this purpose, experiments under controlled conditions were carried out at the laboratory scale. At the cell level, transient behaviours were observed, particularly in the presence of supersaturating light. Photoacclimation impacted photoprotection and photoinhibition mechanisms of the cells. At the reactor scale, characteristic times of photosynthetic responses were explored during increasing or decreasing light step transitions. Subsequently, an in vivo chlorophyll a fluorescence measurement sensor was implemented online on a PBR and its usefulness was studied for monitoring solar cultures, particularly for maintaining good culture conditions and estimating productivity. In addition, this probe supplemented by gas flux measurements also made it possible to measure the impact of PBR dark fractions on the photosynthetic response of C. vulgaris.; La production à grande échelle de micro-algues est principalement réalisée en cultures solaires. Dans ces conditions, les cellules subissent de nombreuses variations de lumière à cause des cycles jour/nuit, de la météo, de leur déplacement entre la surface éclairée et le fond sombre de la culture ou de leur passage régulier dans des parties non éclairées du photobioréacteur (PBR). En réponse à ces variations, les micro-algues ont développé des mécanismes leur permettant de se protéger à court terme contre de trop fortes intensités lumineuses, par exemple en dissipant l’énergie excédentaire sous forme de chaleur, et à long terme d’utiliser l’énergie lumineuse avec la meilleure efficacité en modifiant leur teneur en pigments. Cette étude porte sur la compréhension et l’optimisation de la conversion photosynthétique de l’énergie lumineuse par Chlorella vulgaris en PBR solaire. Pour cela des expériences en conditions contrôlées ont été réalisées à l’échelle du laboratoire. Au niveau de la cellule, des comportements transitoires ont pu être observés notamment en présence de lumière sursaturante. La photoacclimatation impacte les mécanismes de photoprotection et de photoinhibition des cellules. A l’échelle du PBR, les temps caractéristiques des réponses photosynthétiques de la culture ont été explorés lors de transitions lumineuses ascendantes ou descendantes. Par la suite, une sonde de mesure de la fluorescence de la chlorophylle a a été implémentée en ligne sur un PBR et son utilité a été étudiée pour le suivi de cultures solaires notamment pour le maintien de conditions favorables et l’estimation de la productivité. De plus, cette sonde a également permis de mesurer l’impact des boucles sombres sur la réponse photosynthétique de C. vulgaris grâce à des mesures complémentaires de flux de gaz.

Non-alcoholic fatty liver disease represents the most common liver disease and is characterized by an excess of lipid accumulation in hepatocytes, mainly stored as triglycerides. Phaeodactylum tricornutum is a marine microalga, which is rich in bioactive molecules known to be hepatoprotective, such as n-3 long-chain polyunsaturated fatty acids and fucoxanthin. The aim of this study was to investigate the effects of a carotenoid extract from P. tricornutum in a cellular model of non-alcoholic fatty liver disease induced by palmitate treatment. The combined effects of carotenoids and lipids, especially n-3 long-chain polyunsaturated fatty acids, were also investigated by using a total lipophilic extract. HepG2 cells were exposed for 24 h to 250 &micro, M palmitate with or without the addition of carotenoid extract (6 &mu, g/mL) or total lipophilic extract (100 &mu, g/mL). The addition of carotenoid extract or total lipophilic extract prevented the accumulation of triglycerides, total cholesterol and cholesterol esters. The carotenoid extract and total lipophilic extract also decreased the mRNA expression levels of genes involved in lipogenesis (ACACA, FASN, SCD and DGAT1) and cholesterol esterification (ACAT1/SOAT1). In addition, the total lipophilic extract also downregulated the LXR/NR1H3 and SREBF1 genes, which are involved in lipogenesis regulation. By contrast, the carotenoid extract increased the mRNA level of CPT1A, a &beta, oxidation related gene, and reduced the lipid droplet accumulation. In conclusion, this study highlights the preventive effects against non-alcoholic fatty liver disease of the two microalga extracts.

International audience; Oyster production has historically taken place in intertidal zones, and shellfish farms already occupy large extents of the French intertidal space. The expansion of French shellfish aquaculture within intertidal areas is therefore spatially limited, and moving production to the subtidal offshore environment is considered to be a possible solution to this problem. Finding new sites along the French Atlantic coast was studied here from the perspective of small oyster companies run by young farmers, who are interested in offshore bivalve aquaculture expansion compatible with their investment capacity. In assessing the feasibility of such offshore production, we considered three main issues: (1) bivalve growth potential and (2) technical feasibility and conflicting uses, both within a spatial framework, as well as (3) the steps and barriers of the administrative licensing process. Oyster spat in an experimental offshore cage showed significantly faster growth, in terms of both weight and length, compared to those in an intertidal cage, mainly due to lower turbidity and full-time feeding capacity (i.e., constant immersion in the water). A combination of Earth Observation data and bivalve ecophysiological modelling was then used to obtain spatial distribution maps of growth potential, which confirmed that offshore sites have better potential for oyster growth than the traditionally oyster-farmed intertidal sites overall, but that this is highly spatially variable. Small-scale producers indicated two technical factors constraining where farms could be located: bathymetry must be between 5 and 20 m and the distance from a harbor no more than five nautical miles. These were included along with maps of various environmental and socioeconomic constraints in a Spatial Multi-Criteria Evaluation (SMCE). Touristic traffic and bottom trawling by fisherman were found to be the two other most restrictive variables. The GIS-based SMCE developed in this study showed that there is almost 400 km 2 of highly-to very highly-suitable area within which to develop offshore aquaculture using simple, low-cost bottom-cage techniques, and can be used to assist the shellfish industry in the Marine Spatial Planning decision-making process, still in progress in this coastal area. However, the complexity of the administrative processes necessary to obtain an offshore license is perceived as a stronger barrier by farmers owning small companies than site selection, technical feasibility, and required investments, and will be crucial to address in order to realistically proceed to offshore cultivation. The process demonstrated here, and the results are relevant to other coastal and offshore locations throughout the world and can be adapted for other species.

Despite considerable efforts in prevention and therapy, breast cancer remains a major public health concern worldwide. Numerous studies using breast cancer cell lines have shown the antiproliferative and pro-apoptotic effects of docosahexaenoic acid (DHA). Some studies have also demonstrated the inhibitory effect of DHA on the migration and invasion of breast cancer cells, making DHA a potential anti-metastatic agent. Thus, DHA has shown its potential as a chemotherapeutic adjuvant. However, the molecular mechanisms triggering DHA effects remain unclear, and the aim of this study was to provide a transcriptomic basis for further cellular and molecular investigations. Therefore, MDA-MB-231 cells were treated with 100 &micro, M DHA for 1`2 h or 24 h before RNA-seq analysis. The results show the great impact of DHA-treatment on the transcriptome, especially after 24 h of treatment. The impact of DHA is particularly visible in genes involved in the cholesterol biosynthesis pathway that is strongly downregulated, and the endoplasmic reticulum (ER)-stress response that is, conversely, upregulated. This ER-stress and unfolded protein response could explain the pro-apoptotic effect of DHA. The expression of genes related to migration and invasion (especially SERPINE1, PLAT, and MMP11) is also impacted by DHA. In conclusion, this transcriptomic analysis supports the antiproliferative, pro-apoptotic and anti-invasive effects of DHA, and provides new avenues for understanding its molecular mechanisms.

Natural products (NPs) are considered as a cornerstone for the generation of bioactive leads in drug discovery programs. However, one of the major limitations of NP drug discovery program is "rediscovery" of known compounds, thereby hindering the rate of drug discovery efficiency. Therefore, in recent years, to overcome these limitations, a great deal of attention has been drawn towards understanding the role of microorganisms' co-culture in inducing novel chemical entities. Such induction could be related to activation of genes which might be silent or expressed at very low levels (below detection limit) in pure-strain cultures under normal laboratory conditions. In this review, chemical diversity of compounds isolated from microbial co-cultures, is discussed. For this purpose, chemodiversity has been represented as a chemical-structure network based on the "Tanimoto Structural Similarity Index". This highlights the huge structural diversity induced by microbial co-culture. In addition, the current trends in microbial co-culture research are highlighted. Finally, the current challenges (1 - induction monitoring, 2 - reproducibility, 3 - growth time effect and 4 - up-scaling for isolation purposes) are discussed. The information in this review will support researchers to design microbial co-culture strategies for future research efforts. In addition, guidelines for co-culture induction reporting are also provided to strengthen future reporting in this NP field.

International audience; From collected data analyzed to produce an inventory of all polychaetes in Algerian waters, the diversity of this group was estimated as 534 species. The largest families are Syllidae (66 species), Spionidae (37 species) and Terebellidae (27 species). The presence of those listed species along the Algerian coast was compared with their occurrence in nine other areas of the Mediter-ranean Sea, in the Black Sea and in four other more distant seas around the world. Comparisons are also made with respect to the biogeographical origin for each species. The polychaete fauna of the Algerian coast is among the richest of the Mediterranean Sea and comparable to the diversity reported for the French Mediterranean continental shelf and that in the Aegean Sea, but higher that that found in the nearby coastlines of Morocco and Tunisia. Most of the species found have an Atlantic origin and are present in the western Mediterranean Sea. This current inventory includes eight non-indigenous polychaete species found in the Algerian waters.

The development of human activities along the Atlantic coast is responsible for the chronic pollution of the environment with organic and inorganic contaminants. In recent years, environmental regulations such as the MSFD (2008/56/EC) and the OSPAR commission have been developed to preserve coastal environments, giving rise to studies in aquatic biomonitoring. One of them is to use biomarkers to observe the pollutants impact on coastal species such as the bivalve Mimachlamys varia. A defence biomarker was considered in this research to study metal accumulation, with metallothioneins (Mts) involved in the uptake, storage and excretion of metals. To achieve this, bivalves were collected in March 2016 in seven sites along the French Atlantic coasts (open area) and in harbours (semi-open area) with contrasting levels of pollution. Biomarker assays were performed to compare the responses in several tissues (digestive glands, gonads, gills) to inorganic pollutants. The results showed that the accumulation of trace element was different depending on the site and the organ. Mts concentrations were greater in digestive gland compared with gills. Usually, Mts levels were decreased in site showing elevated levels of trace element which explained by downregulation of Mts. Furthermore, results of correlation between Mts and inorganic contaminants and the influence of abiotic factors on Mts suggested that Mts in M. varia is not a relevant biomarker in environments exposed to cocktails of contaminants.

International audience; Estuarine intertidal flats strong biological productivity is mainly based on the activity of benthic microalgae communities or microphytobenthos (MPB), mostly dominated by diatoms. Epipelon is a major MPB growth form comprising motile species, which perform repeated "vertical migration" patterns in the upper sediment layers according to tidal and diurnal cycles with upward migration at the beginning of the daylight emersion and downward migration before immersion starts. Although this fascinating behavior has been extensively studied for more than a century, many of its features remain uncharacterized. Epipelon migratory rhythms are believed to be driven by an endogenous internal clock of unknown nature in combination with diverse environmental stimuli. Among the environmental stimuli impacting on MPB vertical migration, light is probably the most important. Rhythmic changes in surface abundance of natural MPB assemblages were therefore continuously assessed at high frequency by Imaging-PAM fluorimetry in fresh sediment sampled at different seasons, comprising 85 migration profiles from 40 sediment samplings over 2 years, and exposed to different light conditions without any other environmental stimuli (i.e., no tidal-like water flow and stable optimal temperature). In particular, we manipulated (i) the 24-h natural photoperiod MPB that was acclimated to in order to disentangle the tight link between the diurnal and tidal rhythmicity of epipelon migration, and (ii) the light spectrum in order to potentially influence MPB accumulation at the surface of sediment. We found that the migration rhythmicity mapped onto the tidal cycle but that it was modulated, and even overridden, by the diurnal cycle and by the irradiance level during daytime periods with a positive phototactic upward migration up to a certain threshold (in our conditions, 120 µmol photons m −2 s −1 of white light). Also, we found blue wavelengths (465 nm) triggered MPB surface accumulation, as compared to other wavelengths (white, green, and red) in patterns that were intensity-dependent and species-dependent. In particular, we foundtwo species, Navicula spartinetensis and Gyrosigma fasciola, which strongly migrate up under blue light and could potentially be used as model species for further studying the light-responses of intertidal MPB.

International audience; For several decades, use of nanoparticles (NP) on a global scale has been generating new potential sources of organism disruption. Recent studies have shown that NP can cause modifications on the biochemical macromolecular composition of microalgae and raised questions on the toxicity of plastic particles, which are widespread in the aquatic environment. Polystyrene (PS) particles are among the most widely used plastics in the world. In our experimentation, a combined approach of infrared spectroscopy and molecular biology (real-time PCR) has been applied in order to better apprehend the consequences of interactions between Chlamydomonas reinhardtii, freshwater microalgae and PS NP. Two references have been used, nitrogen deprivation -a well-documented stressor-, and gold nanoparticles (Au-NP). As regards biochemical composition, our experiments show a differing microalga response, according to the NP to which they have been exposed. Results with infrared spectroscopy and gene expression methods are consistent and illustrate variation among several carbohydrates (galactose…). Furthermore, PS-NP seem to react in the same direction as nitrogen limitation, thereby supporting the hypothesis that PS-NP can induce response mechanisms to environmental changes in microalgae. This study highlighted the interest of combining infrared spectroscopy and gene expression as means of monitoring microalgae response to nanoplastics.

Polycyclic aromatic hydrocarbons (PAHs), such as benzo[a]pyrene (B[a]P), are environmental pollutants associated with cancers and cardiovascular diseases. The aims of the present thesis have been : (1) to identify biomarkers of a risk of developing these pathologies due to PAHs, and (2) to test the preventing effects of natural products on HMEC-1 endothelial cells. In this context, extracellular vesicles (EV) : exosomes (EXO) and microvesicles (MV), accessible in biological fluids, seem to be promising non-invasive biomarkers. EV composition and production depend on the type and physiopathological state of the cell. Our results demonstrate that some PAHs stimulate in vitro and in vivo EV production and modify their content. We have further shown that the overproduction of EXO depends on the aromatic hydrocarbon receptor (AhR) unlike the MV. We have studied the influence of two extracts of microalgae, O. tauri and P. tricornutum, rich in omega-3 and pigments, on the toxicity of B[a]P. We have observed that O. tauri extract can influence the toxicity of B[a]P. Indeed, apoptosis and EV production were decreased likely through reduction of the expression of CYP1A1, a B[a]P bioactivation enzyme. In addition, the B[a]P-induced expression of the inflammatory cytokines IL-8 and IL1-β was reduced. The P. tricornutum extract only inhibited the expression of the B[a]P-induced cytokine IL-8 expression. Overall, this thesis suggests a potential application of EVs as biomarkers of PAH toxicity, and the possible use of O. tauri extract in the prevention of PAHs-mediated pathologies.; Les hydrocarbures aromatiques polycycliques (HAP), e.g. benzo[a]pyrène (B[a]P), sont des polluants environnementaux associés aux cancers et aux maladies cardiovasculaires. Les objectifs de cette thèse ont été: (1) d’'identifier des biomarqueurs d’'un risque de développement de ces maladies dues aux HAP et (2) de tester des produits naturels en prévention, sur les cellules endothéliales HMEC-1. Dans ce contexte, les vésicules extracellulaires (VE) : exosomes (EXO) et microvésicules (MV), accessibles dans les fluides biologiques, semblent être des biomarqueurs prometteurs non invasifs. La composition et la production des VE dépendent du type et de l’'état physiopathologique de la cellule. Nos résultats démontrent que certains HAP stimulent in vitro et in vivo la production de VE et modifient leur contenu. Nous avons montré que la surproduction d’'EXO dépend du récepteur aux hydrocarbures aromatiques (AhR) contrairement aux MV. Nous avons étudié l’'influence de deux extraits de microalgues, O. tauri et P. tricornutum, riches en oméga-3 et en pigments sur la toxicité du B[a]P. Nous avons observé que l'extrait d’'O. tauri peut influencer la toxicité du B[a]P. En effet, l'apoptose et la production de VE ont diminué probablement par réduction de l'expression du CYP1A1, une enzyme de bioactivation du B[a]P. En outre, l'expression des cytokines inflammatoires induite par le B[a]P a été réduite. L'extrait de P. tricornutum n'a inhibé que l'expression de la cytokine IL-8 induite par le B[a]P. Ces travaux de thèse suggèrent une application potentielle des VE comme biomarqueurs de toxicité des HAP et la possible utilisation d’'O. tauri dans la prévention de pathologies médiées par les HAP.

Over the last fifteen years, blooms of the genus Ostreopsis have been reported more frequently and at higher abundances in the Mediterranean area. Ostreopsis cf. ovata is known to produce ovatoxins (OVTXs), structural analogues of palytoxin, which is one of the most potent non-polymeric toxins. However, the production of OVTXs is poorly characterized in situ. The present study focuses on toxin content and profile according to the bloom phase during summer 2017 in Villefranche-sur-Mer, France (NW Mediterranean Sea), depth (from 0.5 to 5 m) and three different macroalgal substrates of this epiphytic dinoflagellate (Padina pavonica, Dictyota spp. and Halopteris scoparia). Ovatoxin quantification of all samples was performed by liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS). The bloom started at the end of June and declined in mid-July, showing the typical seasonal pattern of the NW Mediterranean Sea area. The peak was observed on the 10 July with 1.8 × 106 cells/g FW and 1.7 × 104 cells/L for benthic and planktonic cells, respectively. Total toxin content of cells, collected using artificial substrates, increased during the exponential and stationary growth phases. After reaching a maximum concentration of 9.2 pg/cell on 18 July, toxin concentration decreased and remained stable from 25 July until the end of monitoring. A decreasing trend of the abundance and of the associated total toxin content was noted with depth. Finally, the decreasing order of maximal epiphytic concentration of O. cf. ovata was: Dictyota spp. (8.3 × 105 cells/g FW), H. scoparia (3.1 × 105 cells/g FW) and P. pavonica (1.6 × 105 cells/g FW). Interestingly, the highest OVTX quota was obtained in cells present on Halopteris scoparia, then on Dictyota spp. and Padina pavonica. This suggests that the nature of the macroalgal substrate influences both growth and toxin production of O. cf. ovata and further work will be required to understand the underlying mechanisms (e.g., competition for nutrition, pH or allelopathic interaction). However, the toxin profiles (i.e., the proportion of each ovatoxin analogue) were not affected by any of the studied parameters (bloom phase, depth, macroalgae or artificial substrates).

Bio-colonisation affects the ageing of materials and the behaviour of offshore structures. Mooring systems and umbilicals belong to the family of slender bodies which are components sensitive to bio-colonisation because of a change of dynamic behaviour due to shape, roughness and mass modifications. However, this stochastic process in time and space is hard to predict. The purpose is then twofold: first, to provide a stochastic spatial model of the bio-colonisation on a mooring line, second, to show that in some defined environmental conditions, such as low wave height, low wind and current velocities, the monitoring of mooring lines tension can help to assess and reduce uncertainty on this model. Therefore, a comprehensive stochastic modelling based on mussels colonisation was carried out using on-site videotapes, experimental campaigns and expert knowledge. We studied the efficiency of a virtual sensing network using this model and a conditional entropy metric. It is first shown that the spatial model fits well with experimental data, and second that a denser medium accuracy sensor network is to be preferred to a single high accuracy fairlead sensor to reduce the uncertainty on the model parameters. It is then worth updating bio-colonisation on mooring lines during the life-time of a floating wind turbine.

International audience; Aquaculture increasingly contributes to global seafood production, requiring new farm sites for continued growth. In France, oyster cultivation has conventionally taken place in the intertidal zone, where there is little or no further room for expansion. Despite interest in moving production further offshore, more information is needed regarding the biological potential for offshore oyster growth, including its spatial and temporal variability. This study shows the use of remotely-sensed chlorophyll-a and total suspended matter concentrations retrieved from the Medium Resolution Imaging Spectrometer (MERIS), and sea surface temperature from the Advanced Very High Resolution Radiometer (AVHRR), all validated using in situ matchup measurements, as input to run a Dynamic Energy Budget (DEB) Pacific oyster growth model for a study site along the French Atlantic coast (Bourgneuf Bay, France). Resulting oyster growth maps were calibrated and validated using in situ measurements of total oyster weight made throughout two growing seasons, from the intertidal zone, where cultivation currently takes place, and from experimental offshore sites, for both spat (R-2 = 0.91; RMSE = 1.60 g) and adults (R-2 = 0.95; RMSE = 4.34 g). Oyster growth time series are further digested into industry-relevant indicators, such as time to achieve market weight and quality index, elaborated in consultation with local producers and industry professionals, and which are also mapped. Offshore growth is found to be feasible and to be as much as two times faster than in the intertidal zone (p < 0.001). However, the potential for growth is also revealed to be highly variable across the investigated area. Mapping reveals a clear spatial gradient in production potential in the offshore environment, with the northeastern segment of the bay far better suited than the southwestern. Results also highlight the added value of spatiotemporal data, such as satellite image time series, to drive modeling in support of marine spatial planning. The current work demonstrates the feasibility and benefit of such a coupled remote sensing-modeling approach within a shellfish farming context, responding to real and current interests of oyster producers.

International audience; The unicellular photosynthetic organisms known as microalgae are becoming one of the most important models for aquaticsystem studies. Among them, Chlamydomonas reinhardtii is widely used as a bioindicator of pollution or of different changes inthe environment. Numerous pollutants are present in aquatic environments, particularly plastics and nanoplastics. Physiologicalvariations after an environmental change highlight variation in the macromolecular composition of microalgae (proteins, nucleicacids, lipids and carbohydrates). Recently, Fourier transform infrared vibrational spectroscopy has been described as a reliabletool, sensitive and allowing rapid measurement of macromolecular composition of microalgae. Coupled with preprocessing andprincipal component analysis, it is well adapted to monitoring the effect of environmental stress on biochemical composition. Inthis study, infrared spectroscopy, combinedwithmultivariate analysis, has been tested first on known environmental stresses suchas light intensity variation and nitrogen limitation. Then, this technique has been applied to monitor the interaction and potentialimpacts of polystyrene nanoparticles on microalgae. The results showed slight variations on protein and carbohydrates bands inthe presence of nanoplastics, suggesting that their presence led to modifications in the biochemical composition of themicroalgae. To confirm the interaction between microalgae and nanoplastics, visualization by confocal microscopy and cytotoxicitymeasurement has been carried out. Results showed that polystyrene nanoparticles seemed to adsorb on microalgaesurface, leading to a loss of plasma membrane integrity. The resulting chemical modifications, even if moderate, could bedetected by infrared spectroscopy‚ showing that this tool could be very helpful in the understanding of nanoparticlemicroalgaeinteraction mechanisms.

International audience; Background Milk has a specific saturated fatty acid profile and its calcium content may change the kinetics of fat absorption. Objective The goal of this study was to compare the effect on LDL Cholesterol and other risk markers of four isolipidic diets differing by their fat food source, vegetable fat, spring milk fat, winter milk fat or winter milk fat supplemented with calcium, in healthy moderately hypercholesterolemic humans. Individuals and methods This double-blind, randomized trial with four parallel arms included 172 healthy adults with plasma LDL cholesterol (LDL-C) from 130 to 220 mg/dL and triglycerides below 300 mg/dL. Individual meal plans ensured a stable energy intake. In the three diets containing milk fat, milk fat provided 38% of energy. Vegetable fat and spring milk fat diets provided the same amount of saturated fatty acids while the winter milk fat diets were slightly richer in saturated fatty acids. Vegetable fat diet and winter milk fat diets provided the same amount of palmitic acid (7.0% EI), while the spring milk fat diet was slightly poorer in this fatty acid (5.1% EI). Cardiovascular risk markers were analyzed after 8 weeks of dietary intervention. Results There was no significant difference in LDL-C and other markers, except total cholesterol (TC), apo C3 and CRP. TC was significantly higher with spring milk fat than with vegetable fat. Conclusions In this trial, the chosen vegetable fat did not have a significant beneficial effect on LDL-C compared to dairy fat. However, sub-group analysis showed differences in TC, apo C3 and CRP. These results need confirmation and long-term studies aiming at cardiovascular endpoints are warranted.

WOS:000569919500022; This study was focused on the phenolic content and associated cosmetic activities of seven brown marine macroalgae:Alaria esculenta,Ascophyllum nodosum,Bifurcaria bifurcata,Fucus serratus,Halidrys siliquosa,Himanthalia elongata, andLaminaria ochroleuca, selected for their abundance in Brittany and their phlorotannin production. Phlorotannins were extracted by maceration followed by a liquid/liquid purification to obtain fractions enriched in phlorotannins. Seasonal and yearly variations in phenolic contents were investigated thanks to the Folin-Ciocalteu assay to find the best harvesting season for each species.H-1 nuclear magnetic resonance (NMR) was used to validate the presence of phenolic compounds and to compare the species in terms of phenolic signals, as they produce different phlorotannin molecules. Activities required for cosmetic applications (i.e., radical scavenging, antioxidant, photoprotective, and anti-aging activities) were assessed by in vitro tests. Fucales, especiallyA. nodosum,F. serratus,H. elongata, andH. siliquosa, showed higher phenolic contents than Laminariales.Temporal variations were apparent for five seaweeds with the highest phenolic content, notably in autumn. The phenolic content was high regardless of the season and antioxidant and photoprotective activities were similar to those of commercial molecules, allowing year-round algal harvesting. The anti-aging activity ofA. nodosumandF. serratusfractions was higher than the active tea flavonol, epigallocatechin gallate. These results are promising for the use of abundant marine macroalgae as a source of natural active ingredients for cosmetic applications.