Grafted dinuclear zinc complexes for selective recognition of phosphatidylserine: Application to the capture of extracellular membrane microvesicles.

Microvesicles (MVs) are key markers in human body fluids that reflect cellular activation related to diseases as thrombosis. These MVs display phosphatidylserine at the outer leaflet of their plasma membrane as specific recognition moieties. The work reported in this manuscript focuses on the development of an original method where MVs are captured by bimetallic zinc complexes.

Exploring the interaction of N/S compounds with a dicopper center: tyrosinase inhibition and model studies.

Tyrosinase (Ty) is a copper-containing enzyme widely present in plants, bacteria, and humans, where it is involved in biosynthesis of melanin-type pigments. Development of Ty inhibitors is an important approach to control the production and the accumulation of pigments in living systems. In this paper, we focused our interest in phenylthiourea (PTU) and phenylmethylene thiosemicarbazone (PTSC) recognized as inhibitors of tyrosinase by combining enzymatic studies and coordination chemistry methods.

Monitoring the Presence of Genetically Modified Potato EH92-527-1 (BPS-25271-9) in Commercial Processed Food.

The Amflora (EH92-527-1) potato is a genetically modified (GM) potato in which only starch of the amylopectin form is produced. This has been achieved by intervening with the biosynthesis of starch in this variety of potato. The Amflora potato is solely grown for the purposes of enhancing its industrial application.

Probing kojic acid binding to tyrosinase enzyme: insights from a model complex and QM/MM calculations.

An unambiguous picture of the interaction between the inhibitor kojic acid and a model of the dicopper active site of tyrosinase is reported. The observed binding mode probed on bacterial enzyme is confirmed and further refined by QM/MM calculations.

Unsymmetrical binding modes of the HOPNO inhibitor of tyrosinase: from model complexes to the enzyme.

The deciphering of the binding mode of tyrosinase (Ty) inhibitors is essential to understand how to regulate the tyrosinase activity. In this paper, by combining experimental and theoretical methods, we studied an unsymmetrical tyrosinase functional model and its interaction with 2-hydroxypyridine-N-oxide (HOPNO), a new and efficient competitive inhibitor for bacterial Ty. The tyrosinase model was a dinuclear copper complex bridged by a chelated ring with two different complexing arms (namely (bis(2-ethylpyridyl)amino)methyl and (bis(2-methylpyridyl)amino)methyl).

Oxinobactin and sulfoxinobactin, abiotic siderophore analogues to enterobactin involving 8-hydroxyquinoline subunits: thermodynamic and structural studies.

The synthesis of two new iron chelators built on the tris-l-serine trilactone scaffold of enterobactin and bearing a 8-hydroxyquinoline (oxinobactin) or 8-hydroxyquinoline-5-sulfonate (sulfoxinobactin) unit has been described. The X-ray structure of the ferric oxinobactin has been determined, exhibiting a slightly distorted octahedral environment for Fe(III) and a Δ configuration. The Fe(III) chelating properties have been examined by potentiometric and spectrophotometric titrations in methanol-water 80/20% w/w solvent for oxinobactin and in water for sulfoxinobactin.

Glycosiderophores: synthesis of tris-hydroxamate siderophores based on a galactose or glycero central scaffold, Fe(III) complexation studies.

A series of five new hexadentate tris-hydroxamate ligands based on a d-galactose or a glycerol scaffold have been synthesized. Protonation and ferric complex formation constants have been determined from solution studies by potentiometric and spectrophotometric titrations. All ligands form 1:1 Fe:L complexes.

The versatile binding mode of transition-state analogue inhibitors of tyrosinase towards dicopper(II) model complexes: experimental and theoretical investigations.

We describe 2-mercaptopyridine-N-oxide (HSPNO) as a new and efficient competitive inhibitor of mushroom tyrosinase (K(IC) =3.7 μM). Binding studies of HSPNO and 2-hydroxypyridine-N-oxide (HOPNO) on dinuclear copper(II) complexes [Cu(2)(BPMP)(μ-OH)](ClO(4))(2) (1; HBPMP=2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-methylphenol) and [Cu(2)(BPEP)(μ-OH)](ClO(4))(2)) (2; HBPEP=2,6-bis{bis[2-(2-pyridyl)ethyl]aminomethyl}-4-methylphenol), known to be functional models for the tyrosinase diphenolase activity, have been performed.

Continuous muscle activity, Morvan's syndrome and limbic encephalitis: ionic or non ionic disorders?

The early pathophysiologic study showed increasing evidence that autoimmunity is implicated in the pathogenesis of neuromyotonia. Antibodies to voltage gated potassium channel were detected in the serum of patients who had peripheral nerves hyperexcitability and also Morvan's disease or limbic encephalitis. These discoveries offered new approaches to treatments.

[Potassium channelopathies and Morvan's syndromes].

Interest in Morvan's disease or syndrome has grown, owing to its close links with various potassium channelopathies. Potassium is crucial for gating mechanisms (channel opening and closing), and especially for repolarization. Defective potassium regulation can lead to neuronal hyperexcitability.

[Limbic encephalitis--evolving concepts].

Limbic encephalitis is an inflammatory disease localized to the "grand lobe limbique" defined by Broca in 1878, sometimes restricted to the hippocampus, but sometimes including extralimbic abnormalities. The main features are subacute onset, short-term memory disorders and cognitive impairment, temporal seizures, and hippocampic changes on MRI. A list of underlying causes has recently been published Infectious causes used to be frequent (mainly herpes simplex virus).

Oxinobactin, a siderophore analogue to enterobactin involving 8-hydroxyquinoline subunits: synthesis and iron binding ability.

Oxinobactin, a siderophore analogue to enterobactin but possessing 8-hydroxyquinoline instead of catechol complexing subunits, has been synthesized starting from L-serine and 8-hydroxyquinoline. Comparative iron binding studies showed that oxinobactin is as effective as enterobactin for the complexation of Fe(III) at physiological pH but with improved complexing ability at acidic pH.

[Primary muscle cramps].

Primary muscle cramps, without known cause, are very frequent especially in the elderly and during the night. They are different from secondary cramps. Likewise they are to be separated from several syndromes erroneously quoted as cramps.

Vesicles to concentrate iron in low-iron media: an attempt to mimic marine siderophores.

Amphiphilic catechol-type iron chelators were studied with the aim of mimicking the properties of marine bacterial siderophores. The Fe(III) complexation constants and aqueous solution speciation of L(S10), a sulfonated catechol unit that has a C(10) lipophilic carbon chain connected by an amide linkage, were determined by spectrophotometric titration. The calculated value of pFe3+ is 18.

Iron-citrate complexes and free radicals generation: is citric acid an innocent additive in foods and drinks?

The generation of free radicals (Fenton chemistry) from various iron citrate complexes has been studied. Spin trapping methods have been used. The results can question concerning the innocence of added citric acid in foods and cold drinks.

Complexation of the triphosphate anion: tuning the structure of cyclen based macrotricycles with 1,3-dimethylbenzene and 2,6-dimethylpyridine linkers. A potentiometric and NMR study.

The host-guest interaction between orthophosphate, pyrophosphate and triphosphate anions and three cyclen-based macrotricyclic ligands was investigated by potentiometric measurements and NMR spectroscopy. The ligands differ from one another by the nature of their spacers, which are 1,3-dimethylbenzene (TMC), 2,6-dimethylpyridine (TPyC) or a combination of the two (TMPyC). In aqueous solution, each ligand gave protonated species that further formed ternary complexes after binding with anions; these complexes were analyzed as a result of hydrogen bond formation and coulombic attraction between the organic host and the inorganic guest.

Molecular characterization of myophosphorylase deficiency (McArdle disease) in 34 patients from Southern France: identification of 10 new mutations. Absence of genotype-phenotype correlation.

We report on 31 patients and 3 affected siblings (17 males and 17 females) from Southern France with McArdle disease (two from Spanish and three from Portuguese background). Molecular analysis revealed the presence of five previously described mutations: the common p.R50X nonsense mutation, the p.

Design of iron chelators: syntheses and iron (III) complexing abilities of tripodal tris-bidentate ligands.

The interest in synthetic siderophore mimics includes therapeutic applications (iron chelation therapy), the design of more effective agents to deliver Fe to plants and the development of new chemical tools in order to study iron metabolism and iron assimilation processes in living systems. The design of ligands needs a rational approach for the understanding of the metal ion complexing abilities. The octahedral arrangement of donor atoms is the most favourable geometry, allowing the maximum possible distance between their formal or partial negative charges.