Evaluation of the binding constants,bound chemical shifts,and equilibrium stoichiometry for the association of lanthanide shift reagents with carbohydrate derivatives

The molecular associations of tris(dipivalomethanato)europium(III) (1) and of tris(2,2-dimethyl-6,6,7,7,8,8,8,-heptafluoro-3,5-octanedionato)europium(III) (2) with six carbohydrate derivatives have been studied. The interactions of 2 in deuterochloroform solution appear to be “normal”, i.e., the plot of [sugar concentration] versus [induced chemical-shift change]^?1 is linear and can be interpreted in terms of the equilibrium binding constant (K_B) and the bound chemical shifts (°_B). Similar results are found for 1 in carbon tetrachloride solutions. However, in chloroform solutions, non-linear plots are obtained that cannot be simply interpreted. Possible reasons for this behaviour are given.     

Molecular characterization of dopamine-derived quinones reactivity toward NADH and glutathione: Implications for mitochondrial dysfunction in Parkinson disease

Oxidative stress and mitochondrial dysfunction, especially at the level of complex I of the electronic transport chain, have been proposed to be involved in the pathogenesis of Parkinson disease (PD). A plausible source of oxidative stress in nigral dopaminergic neurons is the redox reactions that specifically involve dopamine (DA) and produce various toxic molecules, i.e., free radicals and quinone species (DAQ). It has been shown that DA oxidation products can induce various forms of mitochondrial dysfunction, such as mitochondrial swelling and decreased electron transport chain activity. In the present work, we analyzed the potentially toxic effects of DAQ on mitochondria and, specifically, on the NADH and GSH pools. Our results demonstrate that the generation of DAQ in isolated respiring mitochondria triggers the opening of the permeability transition pore most probably by inducing oxidation of NADH, while GSH levels are not affected. We then characterized in vitro, by UV and NMR spectroscopy, the reactivity of different DA-derived quinones, i.e., dopamine-o-quinone (DQ), aminochrome (AC) and indole-quinone (IQ), toward NADH and GSH. Our results indicate a very diverse reactivity for the different DAQ studied that may contribute to unravel the complex molecular mechanisms underlying oxidative stress and mitochondria dysfunction in the context of PD.     

Effect of Lipid Peroxidation on the Accessibility of Dansyl Chloride Labeling to Lipids and Proteins of Bovine Myelin

In our previous studies we have demonstrated that bovine myelin appears highly susceptible to oxidative damage to both its lipid and protein composition. In order to determine whether these alterations would affect the accessibility of myelin components to a fluorescent probe, we have performed various labeling experiments using dansyl chloride. Results from labeling of purified bovine myelin treated with or without cumene hydroperoxide show that basic protein from treated myelin incorporated more dansyl chloride than basic protein from untreated myelin. This increase of labeling could be prevented by the addition of the antioxdant agent, butylated hydroxytoluene. This evidence suggests that lipid peroxidation may play an important role in the pathogenesis of inflammatory demyelinating diseases.     

Reaction between mammalian amine oxidases and their antibodies

Antibodies have been raised against purified beef plasma, pig plasma and pig kidney amine oxidases. Despite the overall similarity, no immunological cross-reactivity was observed among these enzymes, even using a very sensitive light-scattering technique. The presence of substrate affects the rate of the reaction between kidney diamine oxidase and its antibody, but not that of other amine oxidases.     

Ichnologic note

A discovery of a new site with dinosaur tracks from central Italy dramatically alters former palaeontological and paleogeographical hypotheses on the Jurassic of this area.