Sähkökemiallisesti valmistetut molekyylimallitetut polymeerit epäpuhtauksien detektoinnissa

New electrochemical molecularly imprinted polymers (e-MIPs) for benzo(a)pyrene (BaP) based on vinylferrocene (VFc) as redox tracer directly integrated into binding cavities during polymerization with crosslinker are reported. Impacts on the BaP detection are discussed according to: 1) the addition or no of 4-vinylpyridine (4VP) as comonomer, 2) the use of ethylene glycol dimethacrylate (EDMA) or divinylbenzene (DVB) as crosslinker. After characterization, these new e-MIPs and their corresponding non-imprinted polymers (e-NIPs) were incorporated in carbon paste electrodes and measurements were carried out by square wave voltammetry. All analyses revealed that e-MIP based on VFc and EDMA is the best to detect the template, with an imprinting factor of 7.3 and a LOD of 0.93 mu mol/L of BaP.Peer reviewe

Sterols from the brown alga Cystoseira foeniculacea: Degradation of fucosterol into saringosterol epimers

AbstractThe present study was carried out in order to determine the phytochemical composition of the marine brown alga Cystoseira foeniculacea collected off the coasts of Algeria. After a preliminary fractionation of its organic crude extracts by column chromatography, the resulting fractions were further analysed by 1H NMR. Even though algal species of the genus Cystoseira are commonly known to produce a wide variety of meroditerpenoids, in the case of C. foeniculacea none of the fractions were found to contain such compounds: most of the fractions showed typical 1H NMR signals of fatty acids and derivatives (mainly glycerolipids and glycolipids). Nevertheless, the thorough analysis of a sterol-enriched fraction by RP-C8 HPLC led to the isolation, for the first time from this species, of fucosterol (1) and a mixture of saringosterols (2 and 3). The NMR data of compounds 1–3 were fully determined with the help of 1D and 2D experiments which allowed the reassignment of some attributions in comparison with those reported in the literature. This work also confirms evidence of the oxidative degradation of fucosterol into a C-24 epimeric mixture of saringosterols

Biochemical Trade-Offs: Evidence for Ecologically Linked Secondary Metabolism of the Sponge Oscarella balibaloi

Secondary metabolite production is assumed to be costly and therefore the resource allocation to their production should be optimized with respect to primary biological functions such as growth or reproduction. Sponges are known to produce a great diversity of secondary metabolites with powerful biological activities that may explain their domination in some hard substrate communities both in terms of diversity and biomass. Oscarella balibaloi (Homoscleromorpha) is a recently described, highly dynamic species, which often overgrows other sessile marine invertebrates. Bioactivity measurements (standardized Microtox assay) and metabolic fingerprints were used as indicators of the baseline variations of the O. balibaloi secondary metabolism, and related to the sponge reproductive effort over two years. The bioactivity showed a significant seasonal variation with the lowest values at the end of spring and in early summer followed by the highest bioactivity in the late summer and autumn. An effect of the seawater temperature was detected, with a significantly higher bioactivity in warm conditions. There was also a tendency of a higher bioactivity when O. balibaloi was found overgrowing other sponge species. Metabolic fingerprints revealed the existence of three principal metabolic phenotypes: phenotype 1 exhibited by a majority of low bioactive, female individuals, whereas phenotypes 2 and 3 correspond to a majority of highly bioactive, non-reproductive individuals. The bioactivity was negatively correlated to the reproductive effort, minimal bioactivities coinciding with the period of embryogenesis and larval development. Our results fit the Optimal Defense Theory with an investment in the reproduction mainly shaping the secondary metabolism variability, and a less pronounced influence of other biotic (species interaction) and abiotic (temperature) factors

Recherche de molécules non-toxiques actives en antifouling à partir d'organismes marins de Méditerranée

Alors que les premières formes de vie sont apparues dans les océans il y a près de 4 milliards d'années, les premières espèces terrestres remontent seulement à 400 millions d'années. Malgré cela, les substances naturelles d'origine marine ne représentent que 10% de l'ensemble des molécules isolées à ce jour à partir d'organismes vivants. Ces composés chimiques sont pourtant très spécifiques du fait des particularités du Monde Marin. Au sein des organismes qui les biosynthétisent, ils peuvent notamment intervenir dans la défense chimique contre les parasites et les autres compétiteurs. Ces molécules apparaissent donc comme des alternatives potentielles aux oxydes du tributylétain (TBTO) présents dans les revêtements antifouling et interdits depuis 2008 en raison de leur toxicité. Dans ce contexte et dans le cadre d'un partenariat avec le Parc national de Port-Cros, l'étude de la composition chimique de plusieurs organismes marins méditerranéens, des algues vertes (Caulerpa taxifolia) et brunes (Dictyota sp., Dictyota dichotoma, Cystoseira foeniculacea) ainsi que des bryozoaires, a été entreprise. Ces travaux ont permis l'isolement et la caractérisation structurale d'une vingtaine de métabolites secondaires (dérivés terpéniques et lipidiques, stérols), parmi lesquels huit sont originaux. L'identification de l'ensemble de ces molécules a été réalisée par le biais de l'utilisation de différentes méthodes spectroscopiques (RMN 1D et 2D, SM-HR) et la stéréochimie de certaines d'entre-elles a été établie par RMN (expérience NOESY 1H-1H) et modélisation moléculaire. Des corrections de données spectrales ont été également proposées pour cinq composés connus. Par ailleurs, l'activité anti-adhésion de plusieurs métabolites issus d'algues a été évaluée vis-à-vis d'un biofilm bactérien marin (Pseudoalteromonas sp.) afin de déterminer leur potentiel en tant qu'agents antifouling : plusieurs de ces composés présente une activité intéressante (CE50 = 30 M), certes inférieure à celle du TBTO (CE50 = 10 M), mais largement supérieure à celles de co-biocides utilisés actuellement. Parallèlement à ces travaux, l'analyse des variations temporelles et spatiales de l'expression métabolique de certaines des espèces étudiées a été réalisée à des fins écologiques. D'une part, les extraits mensuels de C. taxifolia présentent généralement une activité anti-adhésion importante quand le taux de caulerpényne dans l'extrait est élevé. D'autre part, d'importantes fluctuations ont notamment été observées dans la composition chimique des bryozoaires Myriapora truncata et Pentapora fascialis en fonction de leur lieu de récolteLess than 10% of all natural products allready described in literature have a marine origin. However, these metabolites are often very specific due to the physicochemical and ecological properties of a such environment. In an ecological point of view, marine secondary metabolites are knowmn to be implicate in the defense against competitors. Thus, these compounds could be considered as potential alternatives to tributyltin derivatives (TBTO) outlawed in 2008 in antifouling coatings due to their high toxicity against non-targeted organisms. In this contexte, the phytochemical investigation of green (Caulerpa taxifolia) and brown algae (Dictyota sp., D. dichotoma, Cystoseira foeniculacea) was performed in partnership with the National Park of Port-Cros. This work led to the isolation of 23 metabolites (terpenes, sterols and lipids), from which 8 were found to be new. <their identification was realized on the basis of their spectroscopic data (NMR, HR-MS...). In some case, stereochemical analyses was established by NMR and molecular modeling while, for 5 known compounds, NMR data have been corrected. In addition, 9 of these metabolites were evaluated for their ant-adhesion activity against a marine bacterial biofilm (Pseudoalteromonas sp.) so as to determinate their potential as antifoulants. Two of them displayed a strong activity (EC50=30uM), lower than the one of TBTO (EC50=10uM), but largely higher than the one of commercial cobiocides used nowadays.Finally, temporal fluctuation in the metabolic expression of C.Taxifolia was studied. The monthly extracts showed generally a strong anti-adhesion activity when the amount of caulerpenyne in the extract was highTOULON-BU Centrale (830622101) / SudocSudocFranceF

Meroditerpene from Cystoseira nodicaulis and its taxonomic significance

International audienceThe first investigations carried out on the lipophilic content of samples of the brown alga, Cystoseira nodicaulis, collected along the Atlantic coasts of France led to the isolation of a single monocyclic meroditerpene previously identified in Cystoseira elegans. This finding supplements the chemical data available about the Sargassaceae family and opens the way to further discussions about taxonomy through comparisons with phylogenetic studies. Cyclized meroditerpenes are a typical feature of the clade that includes C. nodicaulis and its allied species C. elegans and Cystoseira baccata

Characterization of marine eukaryotic biofilms at offshore wind farm sites: assessment of DNA extraction methods and marker gene used for metabarcoding approaches

Among marine lifestyles, biofilms are considered as diversified communities embedded in complex exopolymers whose development depends on several factors, related to both environmental conditions and physical-chemical characteristics of substrates (Antunes et al. 2019, Bellou et al. 2012). For the maritime industry, bio-colonization and its impact on human activities were well-described (Schultz et al. 2011). However, this phenomenon represents a new challenge in Renewable Marine Energies (RME) due to their specificities (materials, structures, localization…). In particular, macro-organism assemblages appeared to include a wide variety of eukaryotic groups but the literature is sparse considering the sequencing of eukaryotic diversity in comparison to those of bacterial communities (Briand et al. 2018, Dang and Lovell 2000, Salta et al. 2013). As a matter of fact, the very small size of some of the eukaryotes and/or their insufficient morphological discernible features appear to considerably limit their detection and identification, leading to underestimate their diversity (Carugati et al. 2015). When talking about molecular approaches, analysis of eukaryotes also represents a challenge because such organisms possess resilient cellular structures which can give poor DNA extraction yield (Hermans et al., 2018Hermans et al. 2018). In addition, SSU rRNA in eukaryotes fails to be as universal as for prokaryotes (Bik et al. 2012, Medinger et al. 2010). However, the use of marker genes from environmental DNA, when focused on the targeted eukaryotic community, remains critical to decoding the complexity of marine biofilms diversity.In this study, four extraction methods, including a preliminary mechanic cell lysis, both soil and biofilm kits, and global approaches, have been compared. We also examined the coverage and the identification capability of several primers to characterize eukaryotic communities colonizing three plastic surface types (polyvinyl chloride, HD polyethylene, and polyamide) which have been immersed in several locations along the French Mediterranean and Atlantic coasts. Sequence quality and number remain the same whatever the extraction method. However, the richness and community structure were clearly affected regardless of the sample type (Figure 1). Finally, two kits (PowerMaxSoil, and PowerBiofilm kits) evaluated in this study were considered as the most powerful overall.Secondly, we amplified and sequenced short fragments of two genes: one region of the mitochondrial Cytochrome Oxidase subunit I (COI) and five variable regions of the 18S small subunit ribosomal DNA (rDNA) gene (V1V2, V4TAR, V4UNI, V7, and V9). The Chao1 index was considerably lower for the CO1 gene compared to those of the 18S rDNA regions. The V4TAR and V7 regions showed a significant highest richness, followed closely by the V1V2 and V9 regions. The 18S rDNA gene sequences were dominated by microeukaryotes whereas the COI sequences were dominated by macro-organisms. Each of the 18rDNA primer pairs also exhibited dissimilar community structures although the dominant taxa seemed to be common.To conclude, our results provided a global assessment of tools dedicated to the description of the diversity of marine eukaryotes biofilms from three surfaces used in the design of RME. Among the four extraction methods described here, PowerMaxSoil and PowerBiofilm kits allowed recovering the highest diversity. COI and 18S rDNA gene sequencing covered different groups including at high taxonomic levels. Despite limitations, metabarcoding will help in the characterization of marine biofilms diversity on RME. Especially, it may be relevant to use primers targeting these two genes to better cover the eukaryotic diversity

Caractérisation chimique d'une résine naturelle en Égypte ancienne : application à un exemple de la collection Victor Loret.

L41 is a sample of Victor Loret's collection from the Egyptologic Institute (Lyon II University, Pr. J.-C. Goyon). It was recovered from excavations at Dashour in 1894-1 895 by the archaeologist J. de Morgan. It comes from a flask of princess Sat-mer-hout's funeral endowment (XIIth dynasty). As written, it may be a ritual fragance or, at least, an artificial composition. This material was analysed by HPLC (High Performance Liquid Chromatography) with a double detection (PDA/ fluorimetry) and the result show a mixture of two natural plant resins : a diterpenic pine resin and a triterpenic one to frankincense (Burseraceae family, Boswellia genus).L'échantillon L41 provient de la collection Victor Loret de l'Institut d'Egyptologie (Université Lyon II, Pr J.-C. Goyon). Il a été prélevé lors des fouilles que l'archéologue J. de Morgan effectua sur le site de Dashour dans les années 1 894 et 1 895. Ce prélèvement est issu de la dotation funéraire de la princesse Sat-mer-hout (XIIème dynastie) ; la suscrip- tion du flacon d'où fut tiré L41 évoque la possibilité d'un parfum rituel ou du moins d'une composition artificielle. L'analyse du matériau menée par Chromatographie Liquide à Haute Performance (CLHP) équipée d'une double détection barrette de photodiodes/fluorimétrie met en évidence l'existence d'un mélange d'au moins deux résines végétales l'une diterpénique appartenant à la famille des Pinacées, l'autre de nature triterpénique correspondant à de l'oliban (encens véritable, famille des Burséracées).Mathe Carole, Archier Paul, Culioli Gérald, Vieillescazes Catherine. Caractérisation chimique d'une résine naturelle en Égypte ancienne : application à un exemple de la collection Victor Loret.. In: Revue d'Archéométrie, n°27, 2003. pp. 43-47

Eukaryotic diversity of marine biofouling from coastal to offshore areas

International audienceMarine biofouling communities, including biofilms, are composed of many eukaryotes with high taxonomic and functional diversities. However, molecular characterization of eukaryotic diversity of marine biofouling has been barely developed due to the only recent interest in research areas such as marine renewable energies, antifouling technologies, or plastic pollution. The aim of this study was to compare the diversity and taxonomic composition of biofouling through different metabarcoding approaches used to detect the widest range of taxa from samples collected in several contrasted marine environments (French Atlantic and Mediterranean coasts). Thus, we assessed four DNA extraction methods and six primers pairs targeting the 18S rDNA gene (including the V1-V2, V4TAR, V4UNI, V7 and V9 regions) and the COI gene, the latter with two databases (BOLD and MIDORI). In addition the influence of primers selection was analyzed at three sites to compare geographic variations in eukaryotic diversity. Although none of the extraction methods greatly altered the community diversity or composition. we have observed that eukaryotic biofouling community diversity and structure varied depending on primers pairs, reference databases and sites. 18S rDNA regions allowed the detection of more taxa at the species level, including microeukaryotes, while the COI recovered more ASVs, but with a large proportion that remained taxonomically unassigned probably because BOLD and MIDORI specifically targeted metazoans. Interestingly, the spatial pattern obtained with both COI and 18S rDNA markers were similar showing that spatial selection occurred throughout a wide diversity of eukaryotic taxa. These results encouraged the use of these two complementary markers for future metabarcoding investigations but also highlighted the relevance of completing databases to enhance the identification of biofouling eukaryotes

LC/ESI-MSn and 1H HR-MAS NMR analytical methods as useful taxonomical tools within the genus Cystoseira C. Agardh (Fucales; Phaeophyceae)

International audienceSpecies of the genus Cystoseira are particularly hard to discriminate, due to the complexity of their morphology, which can be influenced by their phenological state and ecological parameters. Our study emphasized on the relevance of two kinds of analytical tools, (1) LC/ESI-MSn and (2) 1H HR-MAS NMR, also called in vivo NMR, to identify Cystoseira specimens at the specific level and discuss their taxonomy. For these analyses, samples were collected at several locations in Brittany (France), where Cystoseira baccata, C. foeniculacea, C. humilis, C. nodicaulis and C. tamariscifolia were previously reported. To validate our chemical procedure, the sequence of the ITS2 has been obtained for each species to investigate their phylogenetic relationships at a molecular level. Our study highlighted the consistency of the two physico-chemical methods, compared to "classical" molecular approach, in studying taxonomy within the genus Cystoseira. Especially, LC/ESI-MSn and phylogenetic analyses converged into the discrimination of two taxonomical groups among the 5 species. The occurrence of some specific signals in the 1H HR-MAS NMR spectra and/or some characteristic chemical compounds during LC/ESI-MSn analysis could be regarded as discriminating factors. LC/ESI-MSn and 1H HR-MAS NMR turned out to be two relevant and innovative techniques to discriminate taxonomically this complex genus

Surface metabolites of the brown alga Taonia atomaria have the ability to regulate epibiosis

This study aimed to improve understanding of the strategies developed by the Mediterranean seaweed Taonia atomaria to chemically control bacterial epibiosis. An experimental protocol was optimized to specifically extract algal surface-associated metabolites by a technique involving dipping in organic solvents whilst the integrity of algal cell membranes was assessed by fluorescent microscopy. This methodology was validated using mass spectrometry-based profiles of algal extracts and analysis of their principal components, which led to the selection of methanol as the extraction solvent with a maximum exposure time of 15 s. Six compounds (A–F) were identified in the resulting surface extracts. Two of these surface-associated compounds (B and C) showed selective anti-adhesion properties against reference bacterial strains isolated from artificial surfaces while remaining inactive against epibiotic bacteria of T. atomaria. Such specificity was not observed for commercial antifouling biocides and other molecules identified in the surface or whole-cell extracts of T. atomaria