Simulated sunlight-induced photodegradations of triasulfuron and cinosulfuron in aqueous solutions     

Vulliet E  Emmelin C  Grenier-Loustallot MF  Païssé O  Chovelon JM 《Journal of agricultural and food chemistry》2002,50(5):1081-1088

To elucidate the photochemical behavior of two sulfonylureas (cinosulfuron and triasulfuron) for which the chemical formulas are relatively close, their photodegradation was studied in water. All experiments were carried out under laboratory conditions using a xenon arc lamp as the source of radiation to simulate environmental conditions. Polychromatic quantum efficiencies were calculated to determine the photochemical pesticide lifetimes at pH 7, and a comparison with hydrolysis lifetimes has been performed. The results obtained showed clearly that at pH 7, photodegradation becomes a more important pathway than chemical degradation. HPLC-DAD was used to study the kinetics for both sulfonylureas and their photoproducts, whereas HPLC-MS (ESI in positive and negative modes) was used to identify photoproducts. These results suggest that the photodegradation of these two sulfonylureas proceeds via a number of reaction pathways: (1) cleavage of the sulfonylurea bridge; (2) desulfonylation, which can proceed either by a carbon-sulfur cleavage or a nitrogen-sulfur cleavage; (3) O-demethylation of methoxy moieties present on the triazine ring; and (4) O-dealkylation of benzene derivatives. In addition, it was found that the desulfonylation represented the main step and that it was wavelength dependent.  相似文献   

Exposure and effects assessments of Bt-maize on non-target organisms (gastropods, microarthropods, mycorrhizal fungi) in microcosms   总被引：2，自引：2，他引：2  

Annette de Vaufleury  Paulina E. Kramarz  Philippe Binet  Jrome Cortet  Sandra Caul  Mathias N. Andersen  Emmanuelle Plumey  Michael Coeurdassier  Paul H. Krogh 《Pedobiologia》2007,51(3):185-ECOGEN

Potential differences between Bt-maize (MEB307 expressing the insecticidal Cry1Ab protein) and a near-isogenic non-Bt variety (Monumental) in their influence on the garden snail (Helix aspersa), soil microarthropods (Collembola, Actinedida, Acaridida, Gamasida and Oribatida) and mycorrhizal fungi were studied. Growing snails were caged in microcosms allowing the development of Bt or non-Bt-maize (Zea mays L.) on a sandy loam soil. After 3 months exposure, survival and growth of snails were similar in both treatments. Cry1Ab protein was detected in the Bt-maize leaves (22–42.2 μg Bt protein g⁻¹ dry wt), in the snail tissues (0.04–0.11 μg Bt-protein g⁻¹ dry wt) and in their faeces (0.034–5 μg Bt-protein g⁻¹ dry wt). Total soil microarthropod abundance and diversity were similar between control (non-Bt-maize) and the genetically modified (GM) Bt-maize microcosms. The mycorrhizal colonization of roots did not differ between Bt and non-Bt-maize (frequency of mycorrhizal roots was 88.7% and 83.3% respectively). The mycorrhizal infectivity of soils, expressed as MI₅₀ (minimum soil dry weight required to colonize 50% of plants) was measured using red clover. MI₅₀ was similar for soils where Bt or non-Bt-maize was cultivated for 4 months. The detection of Cry1Ab protein in the viscera and faeces of H. aspersa exposed to Bt-maize indicates that snails contribute to the transfer of the Bt-protein from plant to soil or snail predators. This may constitute an alternative route of exposure for Bt-protein in soil, but this was without a negative influence on mycorrhizal fungi or microarthropods. Results showed that Bt-maize was not toxic for the selected non-target species exposed for 3 or 4 months. The microcosms and analyses used in this study represent new methods for assessing effects of chronic exposure to GM plants of several diverse, yet ecologically and temporally associated species. As the soil organisms we studied can also be used in standardized ecotoxicological tests (XP X31-205-2 for mycorrhizal fungi, ISO 11267 for Collembola and ISO 15952 for snails), microcosm exposures represent a way to link laboratory and field methods for the ecotoxicological evaluation of GM plants.  相似文献   

Questions experimental design in study on effects of furosemide on racing times of Thoroughbreds     

R Vulliet 《American journal of veterinary research》1990,51(9):1505-1506

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Structural basis of RNA-dependent recruitment of glutamine to the genetic code     

Oshikane H  Sheppard K  Fukai S  Nakamura Y  Ishitani R  Numata T  Sherrer RL  Feng L  Schmitt E  Panvert M  Blanquet S  Mechulam Y  Söll D  Nureki O 《Science (New York, N.Y.)》2006,312(5782):1950-1954

Glutaminyl-transfer RNA (Gln-tRNA(Gln)) in archaea is synthesized in a pretranslational amidation of misacylated Glu-tRNA(Gln) by the heterodimeric Glu-tRNA(Gln) amidotransferase GatDE. Here we report the crystal structure of the Methanothermobacter thermautotrophicus GatDE complexed to tRNA(Gln) at 3.15 angstroms resolution. Biochemical analysis of GatDE and of tRNA(Gln) mutants characterized the catalytic centers for the enzyme's three reactions (glutaminase, kinase, and amidotransferase activity). A 40 angstrom-long channel for ammonia transport connects the active sites in GatD and GatE. tRNA(Gln) recognition by indirect readout based on shape complementarity of the D loop suggests an early anticodon-independent RNA-based mechanism for adding glutamine to the genetic code.  相似文献   

Herpes simplex virus encephalitis in human UNC-93B deficiency     

Casrouge A  Zhang SY  Eidenschenk C  Jouanguy E  Puel A  Yang K  Alcais A  Picard C  Mahfoufi N  Nicolas N  Lorenzo L  Plancoulaine S  Sénéchal B  Geissmann F  Tabeta K  Hoebe K  Du X  Miller RL  Héron B  Mignot C  de Villemeur TB  Lebon P  Dulac O  Rozenberg F  Beutler B  Tardieu M  Abel L  Casanova JL 《Science (New York, N.Y.)》2006,314(5797):308-312

Herpes simplex virus-1 (HSV-1) encephalitis (HSE) is the most common form of sporadic viral encephalitis in western countries. Its pathogenesis remains unclear, as it affects otherwise healthy patients and only a small minority of HSV-1-infected individuals. Here, we elucidate a genetic etiology for HSE in two children with autosomal recessive deficiency in the intracellular protein UNC-93B, resulting in impaired cellular interferon-alpha/beta and -lambda antiviral responses. HSE can result from a single-gene immunodeficiency that does not compromise immunity to most pathogens, unlike most known primary immunodeficiencies. Other severe infectious diseases may also reflect monogenic disorders of immunity.  相似文献   

Comparison of the lipase activity in hydrolysis and acyl transfer reactions of two latex plant extracts from babaco (Vasconcellea x Heilbornii Cv.) and Plumeria rubra: Effect of the Aqueous microenvironment     

Cambon E  Gouzou F  Pina M  Barea B  Barouh N  Lago R  Ruales J  Tsai SW  Villeneuve P 《Journal of agricultural and food chemistry》2006,54(7):2726-2731

The enzymatic properties of Plumeria rubra latex have been evaluated for the first time, showing a high activity in both hydrolysis and synthesis reactions, and compared to the biocatalytic behavior of babaco (Vasconcellea x Heilbornii cv.) latex. Both biocatalysts have been optimized by studying the various parameters that influence reaction kinetics. The optimum temperatures for hydrolysis reactions were 50 and 55 degrees C for babaco and Plumeria, respectively. The optimum pH for babaco latex was 7, whereas for Plumeria latex, two optimal pH values (4 and 7) were observed. With regard to esterification and acyl transfer reactions such as alcoholysis and interesterification, the influence of thermodynamic water activity on reaction yields was determined and correlated with water sorption and desorption isotherms. When babaco latex is used as a biocatalyst, optimal synthesis reaction yields are obtained when the enzymatic extract is stabilized at a water activity value of 0.38, which corresponds to a water content of 5.7%. This optimal level of hydration is located on the linear portion of the biocatalyst's sorption isotherm, where the water molecules exhibit high-energy interactions with the protein network. In synthesis reactions (esterification, alcoholysis, and interesterification) biocatalyzed by Plumeria latex, correlation between best reaction yields and water activity cannot be done. Indeed, the sorption isotherm plot has an atypical shape, indicating that water might be trapped in the latex matrix and, consequently, that the water content of the biocatalyst is highly dependent on the hydration history of the latex.  相似文献   

Identification of equid herpesvirus-5 in respiratory liquids: a retrospective study of 785 samples taken in 2006-2007     

Fortier G  Pronost S  Miszczak F  Fortier C  Léon A  Richard E  Van Erck E  Thiry E  Lekeux P 《Veterinary journal (London, England : 1997)》2009,182(2):346-348

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Soil aggregation may be a relevant indicator of nutrient cation availability     

Léa Bedel  Arnaud Legout  Anne Poszwa  Gregory van der Heijden  Mélanie Court  Noémie Goutal-Pousse  Emmanuelle Montarges-Pelletier  Jacques Ranger 《Annals of Forest Science》2018,75(4):103

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A programmable dual-RNA-guided DNA endonuclease in adaptive bacterial immunity   总被引：2，自引：0，他引：2  

Jinek M  Chylinski K  Fonfara I  Hauer M  Doudna JA  Charpentier E 《Science (New York, N.Y.)》2012,337(6096):816-821

Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) systems provide bacteria and archaea with adaptive immunity against viruses and plasmids by using CRISPR RNAs (crRNAs) to guide the silencing of invading nucleic acids. We show here that in a subset of these systems, the mature crRNA that is base-paired to trans-activating crRNA (tracrRNA) forms a two-RNA structure that directs the CRISPR-associated protein Cas9 to introduce double-stranded (ds) breaks in target DNA. At sites complementary to the crRNA-guide sequence, the Cas9 HNH nuclease domain cleaves the complementary strand, whereas the Cas9 RuvC-like domain cleaves the noncomplementary strand. The dual-tracrRNA:crRNA, when engineered as a single RNA chimera, also directs sequence-specific Cas9 dsDNA cleavage. Our study reveals a family of endonucleases that use dual-RNAs for site-specific DNA cleavage and highlights the potential to exploit the system for RNA-programmable genome editing.  相似文献   

Tex 19 paralogs exhibit a gonad and placenta-specific expression in the mouse     

Celebi C  van Montfoort A  Skory V  Kieffer E  Kuntz S  Mark M  Viville S 《The Journal of reproduction and development》2012,58(3):360-365

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