Trace determination of linear alkylbenzene sulfonates: application in artificially polluted soil-carrots system

Surfactants are widely used in household and industrial products. The risk of incorporation of linear alkylbenzene sulfonates (LAS)from biosolids, wastewater, and fertilizers land application to the food chain is being assessed at present by the European Union. In the present work, a complete analytical method for LAS trace determination has been developed and successfully applied to LAS (C10–C13) uptake in carrot plants used as model. These carrots were grown in soil with the trace organics compounds added directly into the plant containers in pure substances form. LAS trace determination (μg kg−1 dry matter) in carrots samples was achieved by Soxtec apparatus and high-performance liquid chromatography-fluorescence detection. The methodology developed provides LAS determination at low detection limits (5 μg kg−1 dry matter) for carrot sample (2 g dry matter) with good recoveriesate (>90%). Transfer of LAS has been followed into the various parts of the carrot plant. LAS are generally found in the carrot leaves and percentage transfer remains very low (0.02%)

Development and validation of methods for the trace determination of phthalates in sludge and vegetables

A routine method which is simple, quick and precise has been set up and validated for phthalate analysis in environmental samples (tomato plants and sewage sludges). Six phthalates have been studied simultaneously: dimethylphthalate, diethylphthalate, dibutylphthalate, butylbenzylphthalate, di(ethyl)hexylphthalate and dioctylphthalate. Optimization of sample, solvent extraction uses a Soxtec apparatus and extract purification with an SPE cartridge allows between 90 to 110 % recovery of phthalates. Precise, sensitive and selective identification and quantifying of analytes is by GC-MS in SIM mode. This protocol allows analytes with concentrations as low as 10µg/kg Dry Matter (DM) to be determined from small (1 to 2 g DM) samples. This analytical method has been applied to the phthalate transfer study for agricultural recycling of sludges, where phthalate bioavailability has been studied in aquiculture using two types of experiments. Tomatoes have been grown in containers where the trace organics have been directly introduced as pure substances, and in a second experiment under the same growth conditions, sewage sludge has replaced the pure substances. Transfer of these trace organics has been followed into the various parts of the tomato plant and in general only the DEHP is worthy of note although its percentage transfer remains very low even in an experiment designed to maximize this

Paralyzing Action from a Distance in an Arboreal African Ant Species

Due to their prowess in interspecific competition and ability to catch a wide range of arthropod prey (mostly termites with which they are engaged in an evolutionary arms race), ants are recognized as a good model for studying the chemicals involved in defensive and predatory behaviors. Ants' wide diversity of nesting habits and relationships with plants and prey types implies that these chemicals are also very diverse. Using the African myrmicine ant Crematogaster striatula as our focal species, we adopted a three-pronged research approach. We studied the aggressive and predatory behaviors of the ant workers, conducted bioassays on the effect of their Dufour gland contents on termites, and analyzed these contents. (1) The workers defend themselves or eliminate termites by orienting their abdominal tip toward the opponent, stinger protruded. The chemicals emitted, apparently volatile, trigger the recruitment of nestmates situated in the vicinity and act without the stinger having to come into direct contact with the opponent. Whereas alien ants competing with C. striatula for sugary food sources are repelled by this behavior and retreat further and further away, termites defend their nest whatever the danger. They face down C. striatula workers and end up by rolling onto their backs, their legs batting the air. (2) The bioassays showed that the toxicity of the Dufour gland contents acts in a time-dependent manner, leading to the irreversible paralysis, and, ultimately, death of the termites. (3) Gas chromatography-mass spectrometry analyses showed that the Dufour gland contains a mixture of mono- or polyunsaturated long-chain derivatives, bearing functional groups like oxo-alcohols or oxo-acetates. Electrospray ionization-mass spectrometry showed the presence of a molecule of 1584 Da that might be a large, acetylated alkaloid capable of splitting into smaller molecules that could be responsible for the final degree of venom toxicity

Efficacy of a new carvacrol-based product on Campylobacter jejuni in challenge test in vivo and impact on the whole caecal microbiota

Efficacy of a new carvacrol-based product on Campylobacter jejuni in challenge test in vivo and impact on the whole caecal microbiota. 6. International Conference on Poultry Intestinal Healt

Synthese totale du (+) leucotriene B4 et du (#+-#) leucotriene B4 marque au carbone 13. Utilisation de techniques d'hydrozirconation et introduction de la chiralite par biotransformations

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : TD 83641 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Etude toxinologique du venin de fourmis exotiques (identification et caractérisation d'un peptide antimicrobien)

Les venins animaux, par leur richesse biochimique et la diversité de leurs cibles moléculaires, sont une source importante de molécules dont les applications potentielles sont nombreuses. La recherche de nouveaux médicaments pour remplacer certains antibiotiques devenus inefficaces face à l'apparition de résistances, est un axe fort de la recherche pharmacologique. Depuis plus de 40 ans, la découverte de toxines animales montre que les animaux venimeux peuvent être les pharmaciens du futur . Le venin de fourmis est encore peu étudié. Seul celui de quelques espèces a été exploré, avec à chaque fois la mise en évidence de toxines originales. L'objectif de cette thèse a été l'étude du venin de fourmis exotiques sur la base d'une approche pluridisciplinaire qui combine l'analyse biochimique et la toxinologie. Les travaux se sont articulés autour de deux axes principaux : (1) Recherche d'activités biologiques sur insectes et bactéries; (2) Fractionnement des venins par des techniques séparatives et analyse biochimique des peptides isolés par spectrométrie de masse. Deux espèces de fourmis ont été choisies en fonction de leur mode de vie: Crematogaster striatula, une espèce arboricole et Tetramorium bicarinatum, une espèce terricole. Les différentes activités biologiques de leurs sécrétions venimeuses ont été conduites par test MTT. Le liquide de Dufour de C. striatula en plus de sa capacité à éloigner les espèces concurrentes montre une capacité à paralyser les termites de manière irréversible. Concernant le venin de T. bicarinatum, deux peptides ont été isolés et identifiés par spectrométrie de masse. La bicarinaline, peptide de 20 acides aminés et amidé à son extrémité C-terminale, s'est démarqué par son action antibactérienne à large spectre. Testée sur deux souches de staphylocoques, ce peptide se révèle aussi efficace voire plus puissant que la méllitine, peptide antimicrobien du venin d'abeille. La bicarinaline apparaît comme un candidat potentiel pour la conception de nouveaux traitements antibiotiques.Animal venoms, by their biochemical richness and diversity of molecular targets, are a highly significant source of new molecules, with numerous potential applications. A major thrust of present pharmacological research now concerns drugs to replace certain antibiotics, proven ineffective due to the appearance of resistant strains. And discoveries of animal toxins over the past 40 years or more, have shown that venomous species could be the pharmacists of the future , with only a few species of ants' venoms having been studied, but each time resulting in the description of original toxins. The aim of this thesis has been to study the venom of tropical ants using a multidisciplinary approach combining biochemical analysis and toxinology, centred on two main areas: (1) Research into their biological activity on insects and bacteria; (2) Fractionation of venoms using separative techniques, plus biochemical analysis of the peptides isolated using mass spectrometry. Two species of ant have been chosen based on their lifestyles: Crematogaster striatula is arboricolous and Tetramorium bicarinatum, terricolous, and the different biological activities of their crude venoms have been investigated using the MTT test. The Dufour liquid of C. striatula, in addition to its ability to scare away competitors, can definitively paralyse termites. For the venom of T. bicarinatum, two peptides have been isolated, and identified using mass spectrometry. Bicarinalin, a short 20 amino acid residues C-terminally amidated peptide, was notable for its wide spectrum antibacterial activity which, when tested on two Staphylococcus strains, proved to be at least if not more potent than mellitin, the antimicrobial peptide from bee venom. Bicarinalin would thus appear to be a good candidate for the development of new antibiotic drugs.MONTPELLIER-BU Pharmacie (341722105) / SudocSudocFranceF

Bio-raffinage de plantes aromatiques et médicinales appliqué à l'Hibiscus sabdariffa L. et à l'Artemisia annua

L'objectif de l'étude était d'évaluer les potentialités aromatiques et médicinales de deux plantes (Hibiscus sabdariffa et Artemisia annua). Les performances et rendement de plusieurs méthodes d'extraction et de solvants sur des calices et des graines d'hibiscus, issus de trois pays (Vietnam, Sénégal et Mexique) ont été comparés. Les profils en composés volatifs diffèrent selon les extraits. La teneur en acide gras, stérols et tocophérols des huiles des graines d'hibiscus est comparable à celle de l'huile de coton et de soja. Une seconde partie du projet portant sur l'Artemisia du Cambodge et du Sénégal, consiste à établir les conditions de production et la teneur en artémisinine, en terme de stade de développement, date de récolte, type de site. Le bourgeon accumule le maximum d'artémisinine. La teneur en principe actif chute rapidement avec le développement des fleurs. L'Artémisia cultivée au Sénégal présente des taux d'artémisinine moins élevés que l'Artemisia du CambodgeThe aim of this thesis is to assess the potential means of combating poverty and disease through biodiversity of aromatic and medicinal plant : such as Hibiscus sabdariffa and Artemisia annua for developing countries. Hibiscus sabdariffa calyces and seeds from Vietnam, Sénégal and Mexico, were investigated for their performance and yield using several extraction methods and solvents. Significant difference was reported between isolated volatiles. The fatty acid, sterol and tocopherol composition of the seed oil were comparable to the cotton and soy seed oils. The objective of this study was to explore the potential of Artemisia annua for multi-resistant malaria in disavantaged area of Cambodia and Senegal. Two experimental sites and 3 harvesting dates were compared for their active components. The highest levels of artemisinin was found in the buds followed by early and full flowering stage. Artemisia annua cultivated in Senegal showed less yield then those in CambodiaTOULOUSE-ENSIACET (315552325) / SudocSudocFranceF

Influence des modes d'entretien du sol en milieu viticole sur le transfert des pesticides vers les eaux d'infiltration (impact sur les lombriciens)

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

[Editorial] Crop protection, environment, health, and biodiversity: observations and outlook

International audienceThis special issue of Environmental Science and Pollution Research highlights selected papers presented at the 43rd congress organized by the French Group of Pesticide Research (Groupe Français des Pesticides, GFP) which was held in Albi, from 29 to 31 May 2013, and officially hosted by Champollion University, France