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Natural spider silk is one of the world's toughest proteinaceous materials, yet a truly biomimetic spider silk is elusive even after several decades of intense focus. In this study, Next-Generation Sequencing was utilised to produce transcriptomes of the major ampullate gland of two Australian golden orb-weavers, Nephila plumipes and Nephila pilipes, in order to identify highly expressed predicted proteins that may co-factor in the construction of the final polymer. Furthermore, proteomics was performed by liquid chromatography tandem-mass spectroscopy to analyse the natural solid silk fibre of each species to confirm highly expressed predicted proteins within the silk gland are present in the final silk product. We assembled the silk gland transcriptomes of N. plumipes and N. pilipes into 69,812 and 70,123 contigs, respectively. Gene expression analysis revealed that silk gene sequences were among the most highly expressed and we were able to procure silk sequences from both species in excess of 1,300 amino acids. However, some of the genes with the highest expression values were not able to be identified from our proteomic analysis. Proteome analysis of "reeled" silk fibres of N. plumipes and N. pilipes revealed 29 and 18 proteins, respectively, most of which were identified as silk fibre proteins. This study is the first silk gland specific transcriptome and proteome analysis for these species and will assist in the future development of a biomimetic spider silk.

cited By 30; International audience; A reliable and rapid speciation method for the determination of both butyl- and phenyltin compounds in environmental samples has been developed. Organotins are extracted from solid matrices by acid leaching. The analytical procedure is based on the one-step simultaneous ethylation/extraction using the reaction with sodium tetraethylborate in aqueous phase in the presence of isooctane. Direct analysis of the organic layer is performed using gas chromatography interfaced to Flame Photometric Detection (GC-FPD). Absolute detection limits of a few pg tin are reached. The technique has been validated by its application to different polluted environmental samples: wastewaters, sediments and biological tissues from marine and freshwater environments and intercomparisons on freshwater sediment and a mussel sample. © 1997 Taylor & Francis Group, LLC.

We report a novel derivatization chemistry for determination of fluoride based on the batch reaction of fluoride ions with triethyloxonium tetrachloroferrate(III) in a closed vessel to yield fluoroethane. Gaseous fluoroethane was readily separated from the matrix, sampled from the headspace, and determined by gas chromatography/mass spectrometry. The method was validated using rainwater certified reference material (IRMM CA408) and subsequently applied to the determination of fluoride in various matrixes, including tap water, seawater, and urine. An instrumental limit of detection of 3.2 μg/L with a linear range up to 50 mg/L was achieved. The proposed derivatization is a one-step reaction, requires no organic solvents, and is safe, as the derivatizing agent is nonvolatile. Determination of fluoride is affected by common fluoride-complexing agents, such as Al(III) and Fe(III). The effect of large amounts of these interferences was studied, and the adverse effect of these ions was eliminated by use of the method of standard additions.

Landfilling is still nowadays the most used way of municipal solid waste (MSW) management with incineration. MSW landfills remain « black boxes » in which physical, chemical and biological phenomena interact simultaneously. Two effluents are produced during the waste degradation: leachates and biogases. Even if there are limited contact between effluents and the surrounding ecosystem, effluent monitoring is required to improve their treatments and to prevent sanitary and environmental risks. The aim of this work was to develop the methodologies to analyse metals and metalloids in order to assess their fate in landfill effluents. The focus on arsenic (As) and tin (Sn) was motivated by their presence in the municipal solid wastes (glasses, metals, plastics) and in the effluents, and by the difference of toxicity between their species. The development of speciation analysis protocols for As and Sn in the two complex matrices has aimed to their monitoring in the effluents by integrating landfill characteristics and climatic conditions. The occurrence of the species has been examined by taking into account their potential presence in the wastes. Formation and mobilisation processes were proposed to explain their occurrence in the two effluents: first, mobilisation from the waste (inorganic species of As and Sn, butylated and methylated Sn), then methylation and ethylation reactions through biological pathway (methylated As and Sn, ethylated Sn, ionic and gaseous).; Les centres de stockage de déchets (CSD) ménagers et assimilés constituent encore une filière de gestion très répandue Ce sont de véritables « boites noires » dans lesquelles des phénomènes physiques, chimiques et biologiques interviennent simultanément. Deux effluents sont produits au cours de la dégradation des déchets : les lixiviats et les biogaz. Même si le contact entre les effluents et le système environnant est limité, leur suivi est nécessaire pour améliorer leur traitement et prévenir les risques sanitaires et environnementaux. Ce travail a eu pour objectif de mettre en place des méthodologies analytiques adaptées aux métaux et métalloïdes afin d'étudier leur devenir dans les effluents de CSD. L'étude approfondie de l'arsenic (As) et de l'étain (Sn) a été motivée par leur présence dans les déchets (verres, composants métalliques, plastiques), par leur existence sous forme de nombreuses espèces et par la toxicité avérée de certaines de leurs formes chimiques. L'optimisation des protocoles d'analyse de spéciation de As et Sn dans les deux matrices complexes a permis leur suivi au sein des CSD en intégrant les caractéristiques des sites et les données climatiques. La répartition des espèces a été examinée en tenant compte de leur occurrence initiale dans les déchets. Des processus de formation et de mobilisation ont été proposés pour expliquer leur présence dans les deux effluents : d'une part la mobilisation à partir des déchets (espèces inorganiques de As et Sn, espèces butylées et mono- et diméthylées de Sn) et d'autre part la méthylation et l'éthylation par voie biologique (espèces méthylées de As et espèces méthylées et éthylées de Sn, ioniques et gazeuses).

Landfilling is still nowadays the most used way of municipal solid waste (MSW) management with incineration. MSW landfills remain « black boxes » in which physical, chemical and biological phenomena interact simultaneously. Two effluents are produced during the waste degradation: leachates and biogases. Even if there are limited contact between effluents and the surrounding ecosystem, effluent monitoring is required to improve their treatments and to prevent sanitary and environmental risks. The aim of this work was to develop the methodologies to analyse metals and metalloids in order to assess their fate in landfill effluents. The focus on arsenic (As) and tin (Sn) was motivated by their presence in the municipal solid wastes (glasses, metals, plastics) and in the effluents, and by the difference of toxicity between their species. The development of speciation analysis protocols for As and Sn in the two complex matrices has aimed to their monitoring in the effluents by integrating landfill characteristics and climatic conditions. The occurrence of the species has been examined by taking into account their potential presence in the wastes. Formation and mobilisation processes were proposed to explain their occurrence in the two effluents: first, mobilisation from the waste (inorganic species of As and Sn, butylated and methylated Sn), then methylation and ethylation reactions through biological pathway (methylated As and Sn, ethylated Sn, ionic and gaseous).; Les centres de stockage de déchets (CSD) ménagers et assimilés constituent encore une filière de gestion très répandue Ce sont de véritables « boites noires » dans lesquelles des phénomènes physiques, chimiques et biologiques interviennent simultanément. Deux effluents sont produits au cours de la dégradation des déchets : les lixiviats et les biogaz. Même si le contact entre les effluents et le système environnant est limité, leur suivi est nécessaire pour améliorer leur traitement et prévenir les risques sanitaires et environnementaux. Ce travail a eu pour objectif de mettre en place des méthodologies analytiques adaptées aux métaux et métalloïdes afin d'étudier leur devenir dans les effluents de CSD. L'étude approfondie de l'arsenic (As) et de l'étain (Sn) a été motivée par leur présence dans les déchets (verres, composants métalliques, plastiques), par leur existence sous forme de nombreuses espèces et par la toxicité avérée de certaines de leurs formes chimiques. L'optimisation des protocoles d'analyse de spéciation de As et Sn dans les deux matrices complexes a permis leur suivi au sein des CSD en intégrant les caractéristiques des sites et les données climatiques. La répartition des espèces a été examinée en tenant compte de leur occurrence initiale dans les déchets. Des processus de formation et de mobilisation ont été proposés pour expliquer leur présence dans les deux effluents : d'une part la mobilisation à partir des déchets (espèces inorganiques de As et Sn, espèces butylées et mono- et diméthylées de Sn) et d'autre part la méthylation et l'éthylation par voie biologique (espèces méthylées de As et espèces méthylées et éthylées de Sn, ioniques et gazeuses).

cited By 40; International audience; A reliable and rapid speciation method for the simultaneous determination of butyl- and phenyltin species in biological samples has been developed. Three extraction procedures are compared: enzymatic hydrolysis and solubilization by ethanoic and hydrochloric acids. Derivatization is performed by the one-step ethylation/extraction procedure using the sodium tetraethylborate reagent directly in the aqueous phase in the presence of an isooctane layer. Analysis is performed using capillary gas chromatography coupled to flame photometric detection. The detection limits are in the range of a few ng(Sn)/g. Analysis of the environmental samples and the certified reference material demonstrates the accuracy of the analytical method.

International audience; Quantitative volatilization of SeIV from aqueous solutions by its reaction with sodium tetraethylborate was developed and was followed by the determination of selenium by capillary gas chromatography-microwave-induced plasma atomic emission sepectrometry. An essential increase in the selectivity of the determination was observed compared with the commonly used gas chromatography-hydride generation atomic absorption spectrometry. The influence of the medium on the efficiency of the reaction was studied. Hydrochloric acid of 4 mol l-1 was necessary to achieve maximum efficiency in the derivatization. The possibility of applying the derivatizating reaction for the selective determination of SeIV in presence of SeIV is discussed. A microwave-induced plasma was used as an atomizer. A detection limit of 8 ng l-1 (for a 5 ml sample) in a fully automated system was achieved. The method was applied to the determination of selenium in natural water samples.

Treatment of trypsin with triethyloxonium tetrafluoroborate at pH 8, 25 °C, results in abolition of binding to the enzyme of specific cationic substrates and inhibitors. The binding constant of soybean trypsin inhibitor to ethylated trypsin is 10000-fold smaller than to intact trypsin. However, the intrinsic ability of trypsin to recognize and react with nonspecific neutral substrates and inhibitors is not lost, and in several cases even considerably enhanced. Thus ethylated trypsin (Tret) resembles chymotrypsin in its behavior. Trypsin-like enzymes are also affected in a similar manner.

Cultured Chinese hamster ovary cells were treated with ethylating agents. DNA lesions giving rise to single-strand breaks (ssb) or alkali-labile sites were measured by centrifugation in alkaline sucrose gradients after lysis in alkali. 4 agents with different tendencies to ethylate preferentially either at N or O atoms were compared, namely N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG), N-ethyl-N-nitrosourea (ENU), ethyl methanesulphonate (EMS) and diethyl sulphonate (DES). The compounds differed greatly in their potency to induce the lesions measured when compared on a molar basis, but comparison at equicytotoxic doses showed relatively small differences. Upon prolonged incubation of the DNA in alkali, the number of ssb increased considerably. DNA from untreated cells showed biphasic kinetics: slow ssb formation for about 10 h, then the rate increased and remained constant for up to 40 h. Treated cells showed an accelerated, dose-dependent linear generation of ssb for 10 h, followed by a short plateau; then ssb were formed again at a constant rate, somewhat higher than that in controls. Ssb formed in the initial phase are ascribed to phosphotriester hydrolysis, those after the plateau to unidentified causes. Zero intercepts appeared to be a measure of apurinic sites generated intracellularly. A 24-h repair period preceding lysis reduced the ENNG intercept, but not that of DES. Rapid degradation of DES during the 1-h treatment occurred, so most 'apurinic-site lesions' were induced in the beginning of exposure and possibly were already repaired at the end. The types of lesion distinguished (reparable and non-reparable apurinic sites, phosphotriesters) appeared of little consequence for cell survival. Chemicals/CAS: diethyl sulfate, 64-67-5; ethylnitronitrosoguanidine, 4245-77-6; ethylnitrosourea, 759-73-9; mesylic acid ethyl ester, 62-50-0; Alkylating Agents; diethyl sulfate, 64-67-5; DNA, 9007-49-2; ENNG, 4245-77-6; Ethyl Methanesulfonate, 62-50-0; Ethylnitrosourea, 759-73-9; Methylnitronitrosoguanidine, 70-25-7; Sulfuric Acid Esters

p-Nitrophenetole constitutes the starting material for the manufacture of phenacetin, an important synthetic drug. Nitrophenetole is generally prepared by heating the sodium salt of p-nitrophenol with ethyl chloride in an autoclave or with ethyl bromide at ordinary pressure.