Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Chlordecone (Kepone) is an organochlorine insecticide that has been used as insecticide and fungicide. In the French West Indies, Guadeloupe and Martinique, it was intensively applied to banana fields from 1973 to 1993 to control root borers. This pesticide undergoes no significant biotic or abiotic degradation in the environment and is still present in soils where it was applied. It was only in 1999 that health and environmental authorities became aware of the extent of the chlordecone pollution of environmental media, including soils, waterways, and the food chain. Earlier observations and toxicological studies have demonstrated that chlordecone is a reproductive and developmental toxicant, neurotoxic and carcinogenic in rodents, and is an endocrine-disrupting chemical because of its estrogenic properties both in vitro and in vivo. Several surveys have confirmed that the French West Indian population continues to be exposed to this chemical though consumption of contaminated foodstuffs. Here, we report the findings of various epidemiological studies conducted in the French West Indies to assess the impact of environmental exposure to chlordecone on the health of the population.
ISSN: 0944-1344

hal-01150382
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01150382
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01150382/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01150382/file/Chlordecone%20exposure%20and%20adverse%20effects%20in%20French%20West.pdf
DOI : 10.1007/s11356-015-4621-5

Éditeur(s) : HAL CCSD
Résumé : International audience
Background Chlordecone is a persistent organochlorine insecticide with well-defined estrogenic properties. It was intensively used in the French West Indies until 1993 to control the banana root borer. Because of the long-term contamination of soils and water, the population is currently exposed to chlordecone through food consumption. Chlordecone has been found in the blood of pregnant women and in cord blood. It has been shown to be an endocrine-disrupting chemical and exposure during pregnancy may affect fetal growth. Objectives The objective of our study was to examine the association between prenatal exposure to chlordecone and fetal growth based on the TIMOUN birth cohort conducted in Guadeloupe, with a focus on the potential modification of this relationship by maternal body mass index (BMI) and gestational weight gain (GWG). Methods Chlordecone was determined in cord plasma at birth in 593 babies. Birth weight was the indicator of fetal growth. Maternal pre-pregnancy BMI and GWG were determined. Adherence to GWG recommendations of the US Institute of Medicine based on maternal pre-pregnancy BMI was assessed. Birth weight was analyzed relative to cord blood chlordecone levels using linear and non-linear regression models. Results Overall chlordecone in cord blood was not associated with birth weight, but we found an interaction between chlordecone exposure with GWG and adherence to GWG recommendations. After stratification by GWG, we found a significant U-shaped association between birth weight and chlordecone exposure, within the upper quartiles of GWG or excessive GWG. Conclusion Chlordecone exposure may affect fetal growth, particularly when excessive GWG is present. © 2016 Elsevier Inc.
Environmental Research

hal-01367154
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01367154
DOI : 10.1016/j.envres.2016.08.004
PUBMED : 27560981

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Pyrethroids are insecticides frequently used in agriculture and in the home; exposure occurs through dietary and non-dietary pathways, including indoor and outdoor environmental contamination. Our objective was to study the potential determinants of pyrethroid metabolite concentrations measured in children's urine samples and in the dust of their homes. Specifically, we measured urinary metabolites from morning spot samples of 245 six-year- old children living in Brittany (France) in 2009-2012 and from dust vacuumed from the floor of their homes. Mothers reported home insecticide use, dietary habits, sociodemographic data; residential and school proximity to agricultural crops was assessed with spatialized data. The metabolites cis-DBCA, trans-DCCA, cisDCCA, 3-PBA, and F-PBA were detected in 84, 95, 64, 63, and 16% of the urine samples, respectively. Permethrin, cypermethrin, cyfluthrin, deltamethrin, and tetramethrin pyrethroids were detected in 100, 56, 9, 15, and 26% of the dust samples, respectively. Multiple regression analysis suggested diet plays a role in children's exposure, in particular, the food groups "pasta, rice or semolina" (for cis-DCCA and F-PBA), fruit (3-PBA), "breakfast cereals and whole grain bread" (cis-DBCA), and the global proportion of organic food in diet (for cis-DBCA, trans-DCCA). Children with a parent occupationally exposed to pesticides were about 3-times more likely to have higher urinary concentrations of 3-PBA (OR = 2.8, 95% CI [1.2; 6.5]). Dust content was correlated mainly with household insecticide use: higher mean concentrations of permethrin (beta = 0.8 [0.3; 1.3], in mu g/g) and an increased risk of a detectable level of cyfluthrin (OR = 4.7 [1.7; 12.9]) were observed in home dust, for indoor use of at least twice a year. Outdoor insecticide use at least once a year was associated with detection in dust of cypermethrin (OR = 3.0 [1.3; 6.7]) and tetramethrin (OR = 3.7 [1.6; 8.3]). Three positive and one negative correlations (out of 11) between urinary metabolite concentrations and home dust contents of their possible corresponding parent compounds were observed. The strength of this study lies in its concurrent use of biomarkers, environmental measurements, and potential sources of exposure. Its limitations include the use of a single urine sample and imprecise data about pyrethroid use in local agriculture.
ISSN: 0160-4120

hal-01560147
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01560147
DOI : 10.1016/j.envint.2017.04.007
PUBMED : 28453973

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Different household insecticide applications via two electric vaporizers emitting transfluthrin were realized in a full-scale experimental room under controlled air exchange rate conditions. On-line high-time resolved measurements of the gas-phase concentrations of the active substance during and immediately after the spreading periods were performed with a High Sensitivity Proton-Transfer-Reaction Mass Spectrometer (HS-PTR-MS). Experimental and modelled data from the ConsExpo 4.0 software were also compared to evaluate the sources of differences. Different application scenarios were also compared. Averaged inhaled concentrations over 1h, 1week, and 5months were estimated to be 8.3, 1.8, and 1.8μg.m(-3), respectively. Corresponding margins of exposures range from 1000 to 10,000, claiming for the absence of effect. Dermal and dust ingestion pathways, although roughly estimated, seems being non-negligible. This claims for a more in-depth integrated risk assessment.
ISSN: 0160-4120

hal-00875320
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00875320
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00875320/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-00875320/file/Transfluthrin-indoor-accepted.pdf
DOI : 10.1016/j.envint.2013.07.011

Éditeur(s) : GFP : Groupe Français des Pesticides
Extrait de : "Protection des cultures et santé environnementale : héritages et conceptions nouvelles" : congrès, le 26 mai 2014. Université des Antilles et de la Guyane
Description : Lors de cette étude, sont examinée l'évolution des principales familles de substances phytopharmaceutiques de synthèse à usages insecticide, fongicide et herbicide, et leur incidence commerciale. Serons soulignées les mesures prises afin d'assurer une meilleure sécurité de leur emploi et la surveillance dont elles font l'objet, ainsi les démarches mises en oeuvre pour réduire l'utilisation des substances actives de synthèse afin diminuer leur impact environnemental. C'est en fait toute une profession, de l'agriculteur à l'industriel, du chercheur à l'administration en charge du secteur, qui s'est mobilisée pour créer des outils nouveaux et pour explorer des pistes pour penser autrement l'usage des substances phytopharmaceutiques.
Siècle(s) traité(s) : 21
Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V14229
V14229

Éditeur(s) : GFP : Groupe Français des Pesticides
Extrait de : "Protection des cultures et santé environnementale : héritages et conceptions nouvelles" : congrès, le 26 mai 2014. Université des Antilles et de la Guyane
Description : L'objectif de cette étude est d'analyser plusieurs lots des produits épandus et/ou de matières actives ayant servi à les fabriquer et de comparer les rapports massiques 5b-hydro-CLD / CLD détectés dans ces produits avec ceux trouvés dans les sols agricoles prélevés par les agents de la Direction de l'Alimentation, de l'Agriculture et de la Forêt de Martinique de 2007 à 2010 et analysés au Laboratoire Départemental d'Analyse de la Drôme (LDA26). En effet, si la 5b-hydro-CLD correspond à celle apportée par les produits épandus, alors les rapports massiques de 5b-hydro-CLD / CLD dans ces produits et les sols devraient être identiques.
Siècle(s) traité(s) : 21
Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V14188
V14188

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
We assessed the occurrence of algae in five species of tank-bromeliads found in contrasting environmental sites in a Neotropical, primary rainforest around the Nouragues Research Station, French Guiana. The distributions of both algal abundance and biomass were examined based on physical parameters, the morphological characteristics of bromeliad species and with regard to the structure of other aquatic microbial communities held in the tanks. Algae were retrieved in all of the bromeliad species with mean densities ranging from ∼10(2) to 10(4) cells/mL. Their biomass was positively correlated to light exposure and bacterial biomass. Algae represented a tiny component of the detrital food web in shaded bromeliads but accounted for up to 30 percent of the living microbial carbon in the tanks of Catopsis berteroniana, located in a highly exposed area. Thus, while nutrient supplies are believed to originate from wind-borne particles and trapped insects (i.e., allochtonous organic matter), our results indicate that primary producers (i.e., autochtonous organic matter) are present in this insectivorous bromeliad. Using a 24-h incubation of size-fractionated and manipulated samples from this plant, we evaluated the impact of mosquito foraging on algae, other microorganisms and rotifers. The prey assemblages were greatly altered by the predation of mosquito larvae. Grazing losses indicated that the dominant algal taxon, Bumilleriopsis sp., like protozoa and rotifers, is a significant part of the diet of mosquito larvae. We conclude that algae are a relevant functional community of the aquatic food web in C. berteroniana and might form the basis of a complementary non-detrital food web.
ISSN: 1932-6203

hal-00819161
https://hal.archives-ouvertes.fr/hal-00819161
https://hal.archives-ouvertes.fr/hal-00819161/document
https://hal.archives-ouvertes.fr/hal-00819161/file/Brouard2011_AreAlgae.pdf
DOI : 10.1371/journal.pone.0020129

Éditeur(s) : HAL CCSD
Résumé : Genetic structure of Hylesia metabus (Lepidoptera: Saturniidae), moths responsible for lepidopterism outbreaks in French Guiana and Venezuela. . ICE 2016; XXV International Congress of Entomology
ICE 2016; XXV International Congress of Entomology
Orlando, United States

hal-01607289
https://hal.archives-ouvertes.fr/hal-01607289
DOI : 10.1603/ICE.2016.113657
PRODINRA : 396124

Éditeur(s) : GFP : Groupe Français des Pesticides GFP : Groupe Français des Pesticides GFP : Groupe Français des Pesticides
Extrait de : "Protection des cultures et santé environnementale : héritages et conceptions nouvelles" : congrès, le 26 mai 2014. Université des Antilles et de la Guyane
Description : Un certain nombre d'études animales ont démontré la toxicité reproductive et la neurotoxicité développementale des insecticides organophosphorés. Quelques études épidémiologiques suggèrent un rôle de l'exposition aux insecticides organophosphorés sur la croissance foetale de façon concordante pour les groupes de population présentant une susceptibilité génétique particulière (faible activité paraoxonase 1). Ces études sont pour l'essentiel des études de cohorte de population générale nord-américaine. L'objectif est d'étudier l'association entre l'exposition prénatale aux insecticides organophosphorés et la croissance intra-utérine à partir de marqueurs urinaires d'exposition pendant la grossesse et en tenant compte de susceptibilités génétiques potentielles (PON1), à partir d'une cohorte mères-enfants dans la population française.
Siècle(s) traité(s) : 21
Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V14216
V14216
V14216
V14216

Éditeur(s) : HAL CCSD Springer Verlag
Résumé :  
In studying the ant genus Azteca, a Neotropical group of arboreal species, we aimed to determine the extent to which the ants use predation and/or aggressiveness to protect their host plants from defoliating insects. We compared a territorially dominant, carton-nester, Azteca chartifex, and three plant-ant species. Azteca alfari and Azteca ovaticeps are associated with the myrmecophyte Cecropia (Cecropiaceae) and their colonies shelter in its hollow branches; whereas Azteca bequaerti is associated with Tococa guianensis (Melastomataceae) and its colonies shelter in leaf pouches situated at the base of the laminas. Whereas A. bequaerti workers react to the vibrations transmitted by the lamina when an alien insect lands on a leaf making it unnecessary for them to patrol their plant, the workers of the three other species rather discover prey by contact. The workers of all four species use a predatory behaviour involving spread-eagling alien insects after recruiting nestmates at short range, and, in some cases, at long range. Because A. alfari and A. ovaticeps discard part of the insects they kill, we deduced that the workers' predatory behaviour and territorial aggressiveness combine in the biotic defence of their host tree.
ISSN: 0028-1042

hal-01032079
https://hal.archives-ouvertes.fr/hal-01032079
DOI : 10.1007/s00114-008-0448-y

Éditeur(s) : HAL CCSD
Résumé : International audience
Philodendron acutatum (Araceae) is a hemiepiphyte common to the Atlantic Forest of northeastern Brazil. In two localities, we studied the species’ breeding system and associations with flower-visiting insects, along with an analysis of its floral scent composition. The fruit set of self-incompatible P. acutatum was high, more than 90%, and inflorescences were exclusively pollinated by one species of scarab beetle, Cyclocephala celata (Scarabaeidae, Dynastinae). Pollinators are drawn toward the inflorescences at dusk by strong floral fragrancesgiven off during the female phase of anthesis, along with endogenous heating of the spadix, whose temperatures were recorded at more than 11C above ambient air. Two other species of flower-visiting Cyclocephala were also consistently recovered in blacklight trappings during the flowering period of P. acutatum. The fact that only C. celata was found in association with P. acutatum suggests a local reproductivedependence of the plant to this scarab beetle species. Dihydro-b-ionone and 2-hydroxy-5-methyl-3-hexanone, a rare volatile molecule so far unreported as a floral compound, together accounted for more than 97% of the unique scent composition of P. acutatum and might be involved in specific attraction of C. celata.
International Journal of Plant Sciences

hal-01094225
https://hal-agroparistech.archives-ouvertes.fr/hal-01094225
DOI : 10.1086/654846

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
1. Our understanding of the contribution of interspecific interactions to functional diversity in nature lags behind our knowledge of spatial and temporal patterns. Although two-species mutualisms are found in all types of ecosystems, the study of their ecological influences on other community members has mostly been limited to third species, while their influence on entire communities remains largely unexplored. 2. We hypothesized that mutualistic interactions between two respective ant species and an epiphyte mediate the biological traits composition of entire invertebrate communities that use the same host plant, thereby affecting food webs and functional diversity at the community level. 3. Aechmea mertensii (Bromeliaceae) is both a phytotelm ('plant-held water') and an ant-garden epiphyte. We sampled 111 bromeliads (111 aquatic invertebrate communities) associated with either the ant Pachycondyla goeldii or Camponotus femoratus. The relationships between ants, bromeliads and invertebrate abundance data were examined using a redundancy analysis. Biological traits information for invertebrates was structured using a fuzzy-coding technique, and a co-inertia analysis between traits and abundance data was used to interpret functional differences in bromeliad ecosystems. 4. The vegetative traits of A. mertensii depended on seed dispersion by C. femoratus and P. goeldii along a gradient of local conditions. The ant partner selected sets of invertebrates with traits that were best adapted to the bromeliads' morphology, and so the composition of the biological traits of invertebrate phytotelm communities depends on the identity of the ant partner. Biological traits suggest a bottom-up control of community structure in C. fenaoratus-associated phytotelmata and a greater structuring role for predatory invertebrates in P. goeldii-associated plants. 5. This study presents new information showing that two-species mutualisms affect the functional diversity of a much wider range of organisms. Most biological systems form complex networks where nodes (e.g. species) are more or less closely linked to each other, either directly or indirectly, through intermediate nodes. Our observations provide community-level information about biological interactions and functional diversity, and perspectives for further observations intended to examine whether large-scale changes in interacting species/community structure over broad geographical and anthropogenic gradients affect ecosystem functions.
Functional Ecology

hal-01096909
https://hal-agroparistech.archives-ouvertes.fr/hal-01096909
DOI : 10.1111/j.1365-2435-2011.01863.x

Éditeur(s) : PNRM : Parc Naturel Régional de la Martinique DEAL (Martinique) : Direction de l'Environnement, de l'Aménagement et du Logement Région Martinique PNRM : Parc Naturel Régional de la Martinique
Extrait de : "Biodiversité des espaces forestiers et volcaniques de la Martinique : des spécificités à l'exceptionnalité" : atelier scientifique international, les 12 et 13 octobre 2015. Parc naturel régional de la Martinique
Description : Julien TOUROULT, directeur adjoint SPN-MNHN, analyse les Coléoptères longicornes dans les Petites Antilles puis à l'échelle de la Martinique. Il met en évidence la richesse et l'endémisme de groupe d'insectes dans l'arc des Petites Antilles puis il présente l'état des connaissances en Martinique et les prospections en matière de Hotspots.
Siècle(s) traité(s) : 21
Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V15431
V15431
V15431

Éditeur(s) : Communication, ICES Conference and Meeting (CM), 2010, Nantes
Résumé : Chlordecone is a very persistent insecticide used in banana plantations of the French West Indies between 1972 and 1993. Chlordecone residues were found in inland water, in agricultural and freshwater products, and in marine organisms. This pollution has become of great concern in 2007. Therefore, a governmental action Plan was launched to better assess the pollution and to improve the consumer’s protection. Within this plan, 1048 samples from 69 different species of marine fishes and crustaceans were collected all around both the Guadeloupe and the Martinique Islands and analyzed. The results confirm the presence of chlordecone in marine organisms, with highly variable concentrations (from the detection limit to 1000 μg.kg-1). In 17.9 % of the samples, concentrations exceeded 20 μg.kg-1, the maximum acceptable level in fish according to the French regulation (Anon, 2008). Two main features of this contamination were characterized. 1) Because of the sedimentation of contaminated suspended soil particles, the sheltered bays are more exposed to chlordecone than the open coast where terrigenous flux are dispersed. 2) Species biology, particularly their lifestyle and diet, appear to influence contamination levels. Thus, the more contaminated species live in relation with sediment or are at high trophic level. These results have directly supported political decisions in order to prevent too high exposure of consumers to chlordecone. Fishing activities in sheltered bays have been forbidden for potentially highly contaminated species like benthic crustaceans and top predators. Further studies are under way to assess the importance of the trophic transport of chlordecone within the foodweb, and to evaluate the historical deposition of this insecticide in sediment and its further bioavailability.

Droits : 2010 ICES/CIEM ; Ifremer
http://archimer.ifremer.fr/doc/00014/12511/9361.pdf
http://archimer.ifremer.fr/doc/00014/12511/

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Plant-ants live in a mutualistic association with host plants known as "myrmecophytes" that provide them with a nesting place and sometimes with extra-floral nectar (EFN) and/or food bodies (FBs); the ants can also attend sap-sucking Hemiptera for their honeydew. In return, plant-ants, like most other arboreal ants, protect their host plants from defoliators. To satisfy their nitrogen requirements, however, some have optimized their ability to capture prey in the restricted environment represented by the crowns of trees by using elaborate hunting techniques. In this study, we investigated the predatory behavior of the ant Azteca andreae which is associated with the myrmecophyte Cecropia obtusa. We noted that up to 8350 ant workers per tree hide side-by-side beneath the leaf margins of their host plant with their mandibles open, waiting for insects to alight. The latter are immediately seized by their extremities, and then spread-eagled; nestmates are recruited to help stretch, carve up and transport prey. This group ambush hunting technique is particularly effective when the underside of the leaves is downy, as is the case for C. obtusa. In this case, the hook-shaped claws of the A. andreae workers and the velvet-like structure of the underside of the leaves combine to act like natural Velcro that is reinforced by the group ambush strategy of the workers, allowing them to capture prey of up to 13,350 times the mean weight of a single worker.
ISSN: 1932-6203

hal-00818187
https://hal.archives-ouvertes.fr/hal-00818187
https://hal.archives-ouvertes.fr/hal-00818187/document
https://hal.archives-ouvertes.fr/hal-00818187/file/Dejean2010_Arboreal.pdf
DOI : 10.1371/journal.pone.0011331

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
A novel antimicrobial peptide, named Bicarinalin, has been isolated from the venom of the ant Tetramorium bicarinatum. Its amino acid sequence has been determined by de novo sequencing using mass spectrometry and by Edman degradation. Bicarinalin contained 20 amino acid residues and was C-terminally amidated as the majority of antimicrobial peptides isolated to date from insect venoms. Interestingly, this peptide had a linear structure and exhibited no meaningful similarity with any known peptides. Antibacterial activities against Staphylococcus aureus and S. xylosus strains were evaluated using a synthetic replicate. Bicarinalin had a potent and broad antibacterial activity of the same magnitude as Melittin and other hymenopteran antimicrobial peptides such as Pilosulin or Defensin. Moreover, this antimicrobial peptide has a weak hemolytic activity compared to Melittin on erythrocytes, suggesting potential for development into an anti-infective agent for use against emerging antibiotic-resistant pathogens.
ISSN: 0196-9781

hal-00996401
https://hal.archives-ouvertes.fr/hal-00996401
DOI : 10.1016/j.peptides.2012.08.018
PUBMED : 22960382

Résumé : This study contributes to inventory programme on emerging pollutants in French waters and to the general reflection which will enable to update the list of relevant substnaces to be included in the new monitoring programmes to come. This work concerns the coastal part of the inventory programme on marine waters and sediments of France and five overseas french departments (OFD). In this goal, passive sampling techniques and direct extraction techniques have been tested through the implementation of in situ systems integrators POCIS (Polar Organic Chemical Integrative Sampler) and the extraction by SBSE bars (Stir bar sorptive extraction) directly in the waters sampled. Finally, analyzes of sediment completed the acquisition of data. Arount 40 stations were sampled for shore waters and sediments were collected from 7 stations in France and 5 stations in the OFD (one station/OFD). In analytical terms, 1054 analyzes were carried out on POCIS membranes and only 64 data exceeded the limit of detection (LD), 12726 analyzes came from SBSE extractions and 304 were above the LD and 1536 analyzes in sediment showed that 237 data were above the limit of quantification (LQ). Finally, 169 different substances were investigated and 68 of them were detected at least once in water or sediment. The lack of replicates for POCIS analyzes and those in the sediment limited the statistical treatment of data. The results were used to determine the level of contamination, the detection frequency (FD), the distribution of substances between France and OFD, the comparison with environmental thresholds (the PNEC) and the origin/use of the substances. In littoral waters, 32 substances were identified and 19 were quantified. In the sediment, 47 substances were quantified. Nine substances were detected in both water and sediment. In France, the 15 substances that were quantified at higher frequencies (> 50 %, one out of 2 sites) were quantified in sediments. These are the congeners of PAHs (11 substances), organic forms of tin (2 substances), diethyl lead and 209 PBDE congener. In the OFD, the 22 substances that were quantified at higher frequencies (> 50 %, one out of 2 sites) were measured in sediments. These are congeners of PAHs (13 substances) , alkylphenols ( 3 molecules: the mono and diethoxyate nonylphenol and the 4-ter butylphenol ), the organic forms of tin (2 substances), products of metabolism insecticide DDT ( 2 products), diethyl lead and the 209 PBDE congener. The study of the highest concentrations distribution of substances between France and OFD shows that the 5 (among 19 molecules) highest concentrations in water and the 6 (among 47 molecules) highest concentrations in sediments are found in OFD. Reference to PNEC indicates that four pesticides in water and 11 different substances in sediments exceed the environmental thresholds. Substances with highest detection frequency are found in the sediment. The distribution of data by use or nature of the substance shows that plasticizers and pesticides predominate in raw water, both in France and overseas departments while PAHs in sediments dominate in France and in OFD.
Cette étude contribue au programme d’inventaire des substances chimiques émergentes dans les eaux françaises et à la réflexion qui doit permettre d’actualiser la liste des substances pertinentes à surveiller de manière régulière dans le cadre des nouveaux programmes de surveillance. Ce travail concerne la partie littorale de l’inventaire, sur les eaux brutes et les sédiments de la métropole et des 5 DOM. Dans ce cadre, des techniques d’échantillonnage passif (EP) et d’extraction directe ont été testées grâce à la mise en place in situ de systèmes intégrateurs POCIS (Polar Organic Chemical Integrative Sampler) et à l’extraction par des barres SBSE (Stir Bar Sorptive Extraction) directement dans les eaux échantillonnées. Enfin des analyses de sédiments ont complété l’acquisition des données. L’eau d’une quarantaine de stations a été échantillonnée et des sédiments ont été prélevés sur 7 stations en métropole et dans 5 stations dans les DOM (une station par DOM). En termes analytiques, 1054 analyses ont été réalisées sur les membranes POCIS et 64 dépassaient la limite de détection (LD), 12726 analyses ont concerné les extractions par SBSE pour 304 résultats situés au dessus de la LD et 1536 analyses effectuées dans le sédiment ont donné 237 valeurs supérieures à la limite de quantification (LQ). Au bilan 169 substances différentes ont été recherchées et 68 d’entre elles ont été détectées au moins une fois dans l’eau brute ou le sédiment. L’absence de réplicats pour les analyses POCIS et celles dans le sédiment a limité le traitement statistique des données. Les résultats ont permis de déterminer le niveau de contamination, la fréquence de détection (FD), la distribution métropole/DOM des substances, la comparaison avec les seuils environnementaux (PNEC) et l’origine des substances. Dans l’eau 32 substances ont été identifiées et 19 ont été quantifiées. Dans le sédiment 47 substances sont quantifiées .Neuf substances sont détectées à la fois dans l’eau et le sédiment. En métropole, les 15 substances quantifiées aux plus hautes fréquences (> 50%, soit un site sur 2) sont quantifiées dans les sédiments. Ce sont les congénères de la famille des HAP (11 substances), des formes organiques de l’étain (2 substances), le plomb diéthyle et le congénère 209 des PBDE. Dans les DOM, les 22 substances quantifiées aux plus hautes fréquences (> 50%, soit un site sur 2) sont mesurées dans les sédiments. Ce sont des congénères de la famille des HAP dans (13 substances), des alkylphénols (3 substances : nonylphénols mono et diéthoxylés et 4-ter butylphénol), des formes organiques de l’étain (2 substances), des produits de métabolisation de l’insecticide DDT (2 produits), du plomb diéthyle et du congénère 209 des PBDE. L’étude de la répartition des plus fortes concentrations entre la métropole et les DOM montre que les 5 (sur 19) concentrations les plus élevées mesurées dans l’eau et les 6 (sur 47) plus fortes concentrations mesurées dans les sédiments sont trouvées dans les DOM. Les substances mesurées aux fortes fréquences sont observées dans le sédiment. La référence à la PNEC indique le dépassement de la norme pour 4 pesticides dans l’eau brute et 11 substances diverses dans les sédiments. L’exploitation des données par usage ou nature des substances montre que les plastifiants et les pesticides sont majoritaires dans les eaux brutes, à la fois en métropole et dans les DOM alors que ce sont les HAP qui dominent dans les sédiments, en métropole et dans les DOM.

Droits : 2014 ONEMA, Ifremer
http://archimer.ifremer.fr/doc/00259/36994/35483.pdf
http://archimer.ifremer.fr/doc/00259/36994/

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : En Amérique centrale, l’élevage des abeilles sans dard est une pratique vieille d’au moins deux millénaires, qui a connu son apogée à la fin de l’ère maya. Les Méliponinés, sous-famille à laquelle appartiennent ces abeilles, rassemblent près de 500 espèces distribuées pour l’essentiel en zone intertropicale. La plupart d’entre elles nichent dans des cavités d’arbres secs ou sous terre, et affectionnent les forêts ombrophiles où elles assurent un rôle actif dans la pollinisation des plantes sauvages. Sur l’île de Cuba, une seule espèce de méliponinés (Melipona beecheii) est présente, elle a probablement été introduite durant l’époque précolombienne à partir de souches génétiques originaires de la péninsule du Yucatán. Dans les campagnes autour de La Havane, les abeilles mélipones continuent d’être un vecteur de socialisation, car leur domestication correspond souvent à une tradition familiale et parce que les bénéficiaires des produits de la ruche sont des familiers du méliponiculteur. En forêt, en revanche, le miel donne davantage lieu à des pratiques de cueillette. Depuis une vingtaine d’années, la prise de conscience du rôle de l’abeille dans le fonctionnement des écosystèmes et la valeur des services qu’elles seraient susceptibles de rendre à l’agriculture sont à l’origine d’une évolution rapide des représentations sociales associées à l’insecte. Cette évolution contribue à diversifier les profils des éleveurs, à détacher les pratiques du poids des traditions d’élevage ou de cueillette, et à concevoir la méliponiculture comme une activité de loisir voire à envisager son intégration dans une logique marchande.
In central America, stingless beekeeping is a practice older than two thousand years which reached its peak at the end of the Maya era. The melipona sub-family which these bees belong to gather more than 500 species mainly in the intertropical area. Most of them nest in cavities, in dead wood or underground, and have a liking for ombrophile forests where they provide the pollinisation of wild plantes in Cuba. There is only are single species (Melipona beecheii) probably introduced during the pre-colombian era, from genetic strains deriving from the Yucatan peninsula. In the countryside surrounding Havana, the melipona bees are still a vector of socialization, knowing their domestication often results from a familial tradition and is profitable to the beekeeper’s relatives. On the other hand, in the forest, honey is the fruit of gathering. For twenty years now people have been aware of the essential function of bees in the ecosystem and of the valuable services they are able to provide agriculture. This awareness has launched a quick evolution in the social representation of the insect. Thanks to this evolution the beekeepers’ profiles are becoming more diverse, traditions in beekeeping or gathering, weigh less heavily on practices, and the meliponiculture can be regarded as a space-time activity or even a trade one.
Cuba

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.6967
http://journals.openedition.org/etudescaribeennes/6967

Éditeur(s) : HAL CCSD
Résumé : The bacterial microbiota of ants (Hymenoptera: Formicidae) is known to have a defensive role in social insects, particularly for leaf-cutting ants (Formicidae: Attini) due to the use of antimicrobial molecules produced by cuticular actinobacteria. In this thesis, we studied the bacterial microbiota of ants in French Guyana using different approaches based on natural products chemistry and molecular ecology. The first chapter describes the isolation, identification, culture and biological evaluations of 43 cuticular actinobacteria. Antagonism bioassays of isolated strains and antibiotic activities of the culture extracts against human pathogens are presented as well as the identification of an antimicrobial cyclic dipeptide (Cyclo (LPro-LPhe)) isolated from a strain close to Streptomyces thioluteus. Moreover, the implementation of molecular networks applied to UPLC/MS/MS analysis of actinobacterial cocultures allowed us to explore the diversity of metabolites produced under these conditions. The second chapter presents a methodological study to evaluate the capacity of four DNA extraction methods, in terms of richness and composition of the cuticular bacterial microbiota, in high-throughput sequencing from Atta cephalotes and Pseudomyrmex penetrator. The results of metabarcoding highlight two methods of extraction and reveal inter- and intraspecific differences in the composition of cuticular bacterial communities. Finally, chapter three describes the composition of the cuticular bacterial microbiota of Camponotus femoratus and Crematogaster levior in ant garden and the results reveal the acquisition in the environment of a part of the microbiota. In parallel, metabolomic analyses of ant’s cuticle show, on the contrary, a greater specificity related to the ant species. Future researches focusing on statistical analysis strategies combining metabarcoding and metabolomics data are discussed.
Le microbiote bactérien cuticulaire des fourmis (Hymenoptera : Formicidae) est connu pour avoir un rôle défensif chez ces insectes sociaux, notamment chez les fourmis attines (Formicidae : Attini) grâce l’utilisation de molécules antimicrobiennes produites par des actinobactéries cuticulaires. Dans le cadre de cette thèse, nous avons étudié le microbiote bactérien des fourmis de Guyane en utilisant différentes approches en chimie des produits naturels et en écologie moléculaire. Le premier chapitre décrit l’isolement, l’identification, la culture et l’évaluation biologique de 43 actinobactéries cuticulaires de fourmis de Guyane. Les tests d’antagonismes des souches isolées et l’activité antibiotique des extraits de culture contre des micro-organismes pathogènes humains sont présentés ainsi que l’identification d’un dipeptide cyclique (Cyclo(LPro-LPhe)) antimicrobien qui a été isolé à partir d’une souche proche de Streptomyces thioluteus. Par ailleurs, la mise en œuvre de réseaux moléculaires appliqués à une analyse par UPLC/MS/MS de cocultures d’actinobactéries a permis d’explorer la diversité des métabolites produits dans ces conditions. Le deuxième chapitre présente une étude méthodologique pour comparer quatre méthodes d’extraction d’ADN, en termes de richesse et de composition du microbiote bactérien cuticulaire, par séquençage haut débit à partir des espèces Atta cephalotes et Pseudomyrmex penetrator. Les résultats du métabarcoding ADN mettent en lumière deux méthodes d’extraction et révèlent des différences inter- et intraspécifiques dans la composition des communautés bactériennes cuticulaires. Enfin, le chapitre trois décrit la composition du microbiote bactérien cuticulaire des espèces Camponotus femoratus et Crematogaster levior dans les jardins de fourmis. Les résultats soulignent l’acquisition d’une partie du microbiote dans l’environnement. En parallèle l’analyse métabolomique des cuticules montre à contrario une plus grande spécificité liée à l’espèce de fourmi. Les recherches futures axées sur les stratégies d’analyses statistiques combinant le métabarcoding et la métabolomique sont discutées.
https://tel.archives-ouvertes.fr/tel-01537793

NNT : 2017YANE0003
tel-01537793
https://tel.archives-ouvertes.fr/tel-01537793
https://tel.archives-ouvertes.fr/tel-01537793/document
https://tel.archives-ouvertes.fr/tel-01537793/file/thesecarolinebirer.pdf

Éditeur(s) : HAL CCSD American Physiological Society
Résumé : Full text: http://jn.physiology.org/content/88/3/1475
International audience
The contribution of voltage-gated calcium channels (VGCC) to the development of cultured embryonic cockroach brain neurons was assessed using pharmacological agents. VGCC currents were recorded using the patch-clamp technique and were found to be blocked dose-dependently by micromolar concentrations of mibefradil. The activation and inactivation properties of the calcium channels enable a sizeable calcium current to flow at rest (about -30 and -20 mV in high-potassium culture media). As expected, the cytoplasmic-free calcium concentration was found to rise when the extracellular potassium concentration was raised from 3 to 15 and 30 mM. The effects of VGCC blockers and calcium chelators were different in fresh and in mature cultures in which the neurons were connected to each other to form a defined network. In fresh cultures, the two non-selective VGCC blockers (verapamil and mibefradil) induced a dose-dependent cell death that was proportional to their blocking effect on I(Ba). This effect could not be prevented by addition of fetal calf serum to the culture medium. A similar effect was obtained using intra- or extracellular calcium chelating agents (10 microM BAPTA-AM or 10 mM EGTA). Quite unexpectedly, blockade of the P/Q-like (omega-Aga WA-sensitive) component of the calcium current by 500 nM of omega-AgaTx IVA had no lethal effect, suggesting that the corresponding channels are not involved in the survival mechanism. As expected from their lack of effect on I(Ba), isradipine, nifedipine, and omega-CgTx GVIA did not induce cell death. When the neurons started growing neurites, their sensitivity to calcium channel blockade by mibefradil decreased, indicating a correlation between neurite outgrowth and resistance to calcium depletion. In mature cultures, the neurons became resistant to mibefradil, verapamil, and BAPTA-AM. However, these agents, as well as omega-AgaTx IVA, had a significant inhibitory effect on the increase in diameter of the connectives that linked adjacent clusters of neurons. This effect has been shown to result, in the case of mibefradil, from an inhibition of neurite outgrowth characterized by a significant reduction of the number of primary neurites and secondary branchings but not to a significant modification of the diameter of individual neurites. These results support the view that, as in vertebrates, calcium influx through VGCC plays an important role in survival and neurite outgrowth of cultured embryonic insect neurons. The differential contribution of the P/Q-like and R-like (omega-Aga WA-sensitive) calcium channels in these processes is discussed.
ISSN: 0022-3077

hal-00982287
https://hal.archives-ouvertes.fr/hal-00982287
DOI : 10.1152/jn.00749.2001
PUBMED : 12205168