Carboxylate and aromatic active‐site residues are determinants of high‐affinity binding of ω‐aminoaldehydes to plant aminoaldehyde dehydrogenases

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87000/1/j.1742-4658.2011.08239.x.pd

Synthesis of an alkylmagnesium amide and interception of a ring-opened isomer of the important utility amide 2,2,6,6-tetramethylpiperidide (TMP)

Two new magnesium complexes containing the important utility amide 2,2,6,6-tetramethylpiperidide (TMP) have been synthesised. Treating the magnesium bis(alkyl) reagent (Me3SiCH2)2Mg with a molar equivalent of TMP(H) in hydrocarbon medium produces the dimeric alkylmagnesium amide complex [(Me3SiCH2)Mg(μ-TMP)]22, which was isolated in high yield. X-ray crystallography revealed that 2 was an unsymmetrical dimer as unusually the two TMP ligands adopt different conformations – one a chair, the other a twisted boat. Solution studies (multinuclear NMR and DOSY NMR spectroscopies) show that 2 undergoes a monomerisation and Schlenk equilibrium in d8-THF. When (Me3SiCH2)2Mg was reacted with two molar equivalents of TMP(H) in hydrocarbon medium [in an effort to prepare Mg(TMP)2] a crystalline sample of a surprising product, a tetranuclear triheteroanionic amide-alkoxide-amidoalkene [(TMP)Mg(μ-TMP){μ-N(H)C(Me)2CH2CH2CH2C(Me) = CH2}Mg(μ-OCH2SiMe3)]23 was obtained. Complex 3 contains two unexpected anions, namely the alkoxide produced via oxygen insertion into a Mg–C bond, and the primary amidoalkene which is produced via ring opening of the TMP anion

Synthèse de l'apicularène A par une stratégie Chiron

STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

Relations structure-allergénicité dans les protéines de blé

in "INRA en lumière - 5 ans de collaborations avec SOLEIL" [Rapport de recherche

Rapport III.14. Entraînement des pesticides par percolation et ruissellement. Influence particulière du drainage

To know pesticide movement in soils allows not only to study the way of action of these substances (the «location» has some incidence on efficiency) but also may help us to estimate with objectivity the contamination risks for run-off and subterranean waters in areas of intensive farming, i-e in areas where soils are supposed to be regularly treated. For this purpose experimentations or investigations are in progress. The leaching of different pesticides is studied on columns filled with homogeneous soils or in lysimeters. Under field conditions, a monitoring program has been settled. We are controlling the waters collected at the drain exit in beet growing area, and the surface waters from a draining basin of small river in Champagne. The first results obtained under field conditions prove the relatively constant presence of lindane traces in the surface and infiltration waters in fissured or drained soils.La connaissance du déplacement des pesticides dans les sols outre son intérêt dans l’étude du mode d’action (le «placement» n’est pas sans incidence sur l’efficacité), doit nous permettre de juger objectivement les risques de contamination concernant les eaux de ruissellement et les eaux souterraines dans les régions de grande culture, c’est-à-dire dans les zones où a priori les sols sont régulièrement traités. Dans ce but des expérimentations ou des enquêtes sont en cours de réalisation. Au laboratoire ou en station nous étudions la migration de divers pesticides sur des colonnes de sol homogène ou en cases lysimétriques. En plein champ, un programme de surveillance a été mis sur pied. Actuellement nous procédons à la surveillance des eaux collectées à la sortie des drains en régions betteravières et des eaux de surface issues d’un bassin versant en Champagne. Les premiers résultats de plein champ confirment la présence assez constante de traces de lindane dans les eaux de surface et les eaux d’infiltration en terrain fissuré ou drainé.Hascoet M., Jamet P., Piedallu Marie-Andrée, Snegaroff J., Dutil Pierre, Hebert J. Rapport III.14. Entraînement des pesticides par percolation et ruissellement. Influence particulière du drainage. In: Influence des activités de l'homme sur le cycle hydrométéorologique. Compte rendu des treizièmes journées de l'hydraulique. Paris, 16-18 septembre 1974. Tome 1, 1975

(Chiral) lithium-(magnesium-)zinc and lithium-cobalt combinations as dual reagents for aromatic deproto-metalation and aryl transfer to aldehydes.

International audienceThe deprotonating ability of mixed lithium-zinc or lithium-magnesium-zinc combinations contg. amido and alkyl ligands in THF were compared using anisole as substrate and iodine to quant. trap the formed arylmetal species. The results showed that the deprotonating ability is hampered if a Grignard reagent is employed to introduce the alkyl ligand, and is reduced when 2,2,6,6-tetramethylpiperidino ligands are replaced by less hindered/basic chiral amido or alkyls. Concerning the interception of the generated lithium-zinc aryl species by aldehydes, the presence of amido ligands leads to side reactions/lower yields, and no clear improvement was obsd. if lithium-magnesium-zinc aryl species are used. Racemic mixts. to very low enantioselectivities were noted when chiral amido ligands were incorporated in the compn. of the bases. Still with enantioselective aryl transfer to aldehyde as purpose, the deprotonating ability of mixed lithium-cobalt combinations contg. amido and alkyl ligands were compared using anisole as substrate and anisaldehyde to trap the formed arylmetal species. As before, the deprotonating ability is reduced when 2,2,6,6-tetramethylpiperidino ligands are replaced by less hindered/basic alkyls or chiral amido. The trapping step using aldehydes being in this case more efficient, even in the presence of amido ligands, the alcs. were obtained in higher yields. With recourse to a lower interception temp., and using only bis[(R)-1-phenylethyl]amino as ligands, 32 and 22% yield, and 69 and 65% ee were obtained using, resp., anisaldehyde and 3,4,5-trimethoxybenzaldehyde to intercept the metalated anisole. [on SciFinder(R)

Low Molecular Weight Glutenins in Wheat-Dependant, Exercise-Induced Anaphylaxis: Allergenicity and Antigenic Relationships with Omega 5-Gliadins

Background: Adults suffering from wheat-dependant, exercise-induced anaphylaxis (WDEIA) develop IgE directed against wheat ω5-gliadins (major allergens for this allergy) and against wheat low-molecular weight glutenin subunits (LMW-GS). However, the ability of LMW-GS to trigger an inflammatory response is still unknown. It also remains to be determined if IgE from these patients bind the same epitopes on LMW-GS and ω5-gliadins or if the epitopes are independent. Methods: WDEIA patients were selected and skin prick tests (SPTs) were performed on them using commercial gluten, wheat flour extracts, prolamin fractions and a purified natural LMW-GS P42. The IgE-binding ability of natural and recombinant wheat prolamins was verified by immunoblot experiments. Cross-reactivity between LMW-GS and ω5-gliadins was studied by immunoblot inhibition experiments, using purified natural ω5-gliadin as an inhibitor. Results: Patients developed positive SPTs with natural LMW-GS fractions and/or with the purified LMW-GS P42. Natural and recombinant LMW-GS were highly reactive with patient IgE in immunoblot experiments, as was ω5-gliadin. However, differences in reactivity were evident within the LMW-GS group. Except for one recombinant LMW-GS (P73), IgE cross-reactivity between LMW-GS and natural ω5-gliadin was only partial. Conclusion: LMW-GS are able to promote local inflammation and they share common epitopes with ω5-gliadins. The nature of these epitopes is discussed. LMW-GS also carried specific epitopes, completely independent from the ω5-gliadin epitopes. Thus, LMW-GS behaved partly as independent allergens