bêta oxydation

Steam explosion lignin (SEL) was extracted with ethanol from steam exploded hardwood (okoumé, Aucoumea klaineana Pierre) pretreated at various severities after neutral or acidic impregnation. The SELs were subjected to a structural characterization by 2D HSQC NMR, 31P NMR, SEC and compared to Milled Wood Lignin (MWL). A strong decrease in the -O-4 content is observed with increasing steam explosion severity accompanied with a gradual increase in molecular mass. C-oxydized S units (S', Hibbert's ketones) were quantified by NMR and used as a marker of the hydrolytic mechanism as well as naphthol used as a carbonium ion scavenger...

There are several reports that increased oxidative stress and DNA damage were found in β-thalassemia major (β-TM) patients. In this study, we aimed to evaluate the effects of N-acetylcysteine (NAC) and vitamin E on total oxidative stress and DNA damage in children with β-TM. Seventy-five children with transfusion-dependent β-thalassemia (β-thal) were randomly chosen to receive 10 mg/kg/day of NAC or 10 IU/kg/day of vitamin E or no supplementation; 28 healthy controls were also included in the study...

The iminosugar N-(5'-adamantane-1'-yl-methoxy)-pentyl-1-deoxynoijirimycin (AMP-DNM), an inhibitor of glycosphingolipid (GSL) biosynthesis is known to ameliorate diabetes, insulin sensitivity and to prevent liver steatosis in ob/ob mice. Thus far the effect of GSL synthesis inhibition on pre-existing NASH has not yet been assessed. To investigate it, LDLR(-/-) mice were kept on a western-type diet for 12 weeks to induce NASH. Next, the diet was continued for 6 weeks in presence or not of AMP-DNM in the diet...

This study investigates the efficiency of the photocatalytic degradation of metoprolol tartrate (MET), a widely used β(1)-blocker, in TiO(2) suspensions of Wackherr's "Oxyde de titane standard" and Degussa P25. The study encompasses transformation kinetics and efficiency, identification of intermediates and reaction pathways. In the investigated range of initial concentrations (0.01-0.1 mM), the photocatalytic degradation of MET in the first stage of the reaction followed approximately a pseudo-first order kinetics...

The cytochrome P450 OxyD from the balhimycin glycopeptide antibiotic biosynthetic operon of Amycolatopsis mediterranei is involved in the biosynthesis of the modified amino acid beta-R-hydroxytyrosine, an essential precursor for biosynthesis of the vancomycin-type aglycone. OxyD binds the substrate tyrosine not free in solution, but rather covalently linked to the carrier protein (CP) domain of the non-ribosomal peptide synthase BpsD, exhibiting micromolar binding affinity to a tyrosine-loaded carrier protein construct...

Peroxisome proliferator-activated receptor gamma coactivator 1 (PGC1) family is highly expressed in tissues with high energy metabolism. They coactivate transcription factors in regulating genes engaged in processes such as gluconeogenesis, adipose beta-oxydation, lipoprotein synthesis and secretion, mitochondrial biogenesis, and oxidative metabolism. Protein conformation studies demonstrated that they lack DNA binding domains and act as coactivators through physical interaction with transcription factors. PGC1 activity is regulated at transcription level or by multiple covalent chemical modifications such as phosphorylation, methylation and acetylation/deacetylation...

Oxidative stress is commonly observed in chronic renal failure patients resulting from an unbalance between overproduction of reactive oxygen species and impairement of defense mechanisms. Proteins appear as potential targets of uremia-induced oxidative stress and may undergo qualitative modifications. Proteins could be directly modified by reactive oxygen species which leads to amino acid oxydation and cross-linking. Proteins could be indirectly modified by reactive carbonyl compounds produced by glycoxidation and lipo-peroxidation...

Free radicals are thought to play an important part in the phenomenon of aging, especially as regards the eye. Antioxydants represent an interesting means of limiting the damage due to oxydation, as is shown by a number of studies. Food is an unexpected source of antioxydants, which exist in the form of thousands of different compounds. Colored fruits and vegetables are known to be rich in carotenoids, some of which such as lutein and zeaxanthin tend to accumulate at the level of the macula. But there are plenty of other foodstuffs that supply the antiradical armoury, as has been shown by analytical findings over a number of years...

Arterial hypertension is one of the leading causes of atherosclerosis. Many studies of antihypertensive drugs have been recently focused on prevention, stopping and if possible regression of atherosclerosis. Some antihypertensive drugs which are used in clinical practice have antiatherosclerotic effects besides their effects on the reduction of systemic blood pressure. Oxydative processes and oxygen free radicals participate in the pathogenesis of atherosclerosis. The concentration of oxygen free radicals is increased in patients with arterial hypertension...

Rhodococcus erythropolis strain PR4 has been isolated as an alkane-degrading bacterium. The strain harbours one linear plasmid, pREL1 (271 577 bp) and two circular plasmids, pREC1 (104 014 bp) and pREC2 (3637 bp), all with some sequence similarities to other Rhodococcus plasmids. For pREL1, pREC1 and pREC2, 298, 102 and 3 open reading frames, respectively, were predicted. Linear plasmid pREL1 has several regions homologous to plasmid pBD2 found in R. erythropolis BD2. Sequence analysis of pREL1 and pBD2 identified common metal-resistance genes on both, but pREL1 also encodes alkane-degradation genes not found on pBD2, with enzyme constituents some of which are quite different from those of other organisms...

The role of the putative P450 monooxygenase OxyD and the chlorination time point in the biosynthesis of the glycopeptide antibiotic balhimycin produced by Amycolatopsis balhimycina were analyzed. The oxyD gene is located directly downstream of the bhp (perhydrolase) and bpsD (nonribosomal peptide synthetase D) genes, which are involved in the synthesis of the balhimycin building block beta-hydroxytyrosine (beta-HT). Reverse transcriptase experiments revealed that bhp, bpsD, and oxyD form an operon. oxyD was inactivated by an in-frame deletion, and the resulting mutant was unable to produce an active compound...

The title cluster (Pd(3)(2+)) exhibits a pronounced affinity for Br(-) ions to form the very stable Pd(3)(Br)(+) adduct. Upon a 2-electron reduction, a dissociative process occurs generating Pd(3)(0) and eliminating Br(-) according to an ECE mechanism (electrochemical, chemical, electrochemical). At a lower temperature (i.e. -20 degrees C), both ECE and EEC processes operate. This cluster also activates the C-Br bond, and this work deals with the reactivity of Pd(3)(2+) with 2,3,4-tri-O-acetyl-5-thioxylopyranosyl bromide (Xyl-Br), both alpha- and beta-isomers...

The aim of this experiment was to study the consequences of precise feeding on the myofibre characteristics and metabolic traits of the breast muscle (Pectoralis major, Pm) of Muscovy ducks. Twenty-four samples of breast muscle, without skin or subcutaneous fat, from two groups of ducks, control and overfed respectively, were collected at 14 weeks of age. We assayed different chemical (water content, crude proteins, total lipid ashes, total and thermosoluble collagen), biochemical (activities of the CS, LDH and beta-HAD enzymes), histological (muscle fibre typing and intramuscular adipocyte measurements) and technological (drip and cooking losses, texture) determinations...

UNLABELLED: The aim of this study was to examine the diagnostic value of Sodium 11C-Butyrate (11C-Butyrate) in assessing perfusion and oxydative metabolism in patients with coronary artery disease (CAD). 41 patients (39 male and 9 female, mean age 48 +/- 11) with CAD were investigated. PET-scans were performed twice: at 2-7 min and 25-31 min after i.v. injection of 250-400 MBq 11C-Butyrate. Regional perfusion was evaluated by the uptake of radioactivity in the myocardium at the first scan, intensity of beta-oxidation--by decreasing the uptake level at the second scan...

A high level of physical activity is associated with a lower cardiovascular risk in adult and elderly subjects. Several mechanisms are involved. Physical activity induces an increase in energy output. The contribution of fats to muscle energy metabolism increases with exercise duration. It decreases with exercise intensity. EPOC contributes by about 10% to the total energy cost of exercise. This supplementary energy expenditure is principally covered with fat oxidation, this being related to GH release. Part of energy expended during intermittent exercise is supplied by fat oxidation...

The present research work was done with the main purpose to study early stages of interaction of carotenoids (Car) with molecular oxygen and clarify their role in the mechanism responsible for Car radiochemical stability and carotenoid ability to decrease concentration of the most active oxygen transients like superoxide anion radicals (O2.-). Alcoholic and phosphate buffer (pH 7.5) solutions of carotenoid fucoxanthin (Fx) were used for investigation of the oxygen effect on the absorption spectra in the UV-Visible range...

Cytosine arabinoside (AraC) is rapidly inactivated via systemic deamination with half-lives ranging from 1 h (i.v.) to 4 h (s.c.) -- and cannot be applied orally due to its hydrophilic properties. These limitations might be overcome by YNK01 -- a lipophilic prodrug of AraC -- that is resistant to deoxycytidine deaminase and can be applied orally. In the present study the therapeutic activity, side-effects and pharmacokinetics of YNK01 were evaluated in a phase I/II study including patients with relapsed or refractory acute myeloid leukemia (AML) (n=23) or low-grade non-Hodgkin's lymphoma (NHL) (n=20)...

The compound 2,3,5,6-Tetramethylpyrazine (TMP; Ligustrazine), a flavouring component and sweetness enhancer for beverages constitutes a commonly used food additive. Now we studied the effect of TMP on coronary artery dilation during ischemia: In our experiments we used isolated, Langendorff-perfused guinea pig hearts, arrested with K(+)-rich Normal Tyrode solution (in mM: NaCl 129.5, KCl 15, MgCl2 0.8, CaCl2 1.0, glucose 10), buffered with 10 mM HEPES to pH 7.4 at 37 degrees C, equilibrated with 100% O2. Ischemia was simulated by equimolar replacement of glucose by 2-deoxyglucose (DOG), an inhibitor of oxydative phosphorylation...

The HIV and visna lentiviruses induce an inflammatory reaction in the central nervous system (CNS) of the infected hosts leading to dysmyelination, demyelination, and neuronal loss. The basic domain of the transactivating Tat protein has been involved in CNS damage. Infusion of basic containing domain Tat peptides in the lateral ventricle (systemic injection) or in the grey matter, i.e., hippocampus and thalamus (local injection), induced an inflammatory process characterized by the formation of an edema and invasion of macrophage accompanied by reactive astrogliosis...

In malnutrition lipoprotein lipase activity in the liver and the beta-lipoprotein concentration in serum are reduced. The lipolysis is increased. One suspected a reduction of fat elimination in such patients. In 10 malnourished patients with a mean body weight of 73% ideal body weight an intravenous fat tolerance test was performed. The elimination rate was in mean 5.77%/min, that is in the normal range. Studies with radioactive triglycerides showed a metabolization of 30% of infused fat during 24 hours. These results were confirmed by measurements of gas exchange...