Alterations to Cerebral Perfusion,Metabolite Profiles,and Neuronal Morphology in the Hippocampus and Cortex of Male and Female Mice during Chronic Exposure to a High-Salt Diet

Excess dietary salt reduces resting cerebral blood flow (CBF) and vascular reactivity, which can limit the fueling of neuronal metabolism. It is hitherto unknown whether metabolic derangements induced by high-salt-diet (HSD) exposure during adulthood are reversed by reducing salt intake. In this study, male and female mice were fed an HSD from 9 to 16 months of age, followed by a normal-salt diet (ND) thereafter until 23 months of age. Controls were continuously fed either ND or HSD. CBF and metabolite profiles were determined longitudinally by arterial spin labeling magnetic resonance imaging and magnetic resonance spectroscopy, respectively. HSD reduced cortical and hippocampal CBF, which recovered after dietary salt normalization, and affected hippocampal but not cortical metabolite profiles. Compared to ND, HSD increased hippocampal glutamine and phosphocreatine levels and decreased creatine and choline levels. Dietary reversal only allowed recovery of glutamine levels. Histology analyses revealed that HSD reduced the dendritic arborization and spine density of cortical and hippocampal neurons, which were not recovered after dietary salt normalization. We conclude that sustained HSD exposure throughout adulthood causes permanent structural and metabolic alterations to the mouse brain that are not fully normalized by lowering dietary salt during aging.     

Organotypic co-culture system to study plant extract bioactivity on hepatocytes

Natural plant extracts are complex mixtures of molecules that have to be uptaken and metabolized, at least by the intestinal barrier, before they reach their body targets. This paper evaluates the feasibility of using a co-culture system to assay the bioactivity of plant extract on hepatic cells closest to the in vivo situation. Caco-2 cells, mimicking intestinal barrier roles, were grown on inserts on a monolayer of HepG2 hepatocytes for 24 h. The co-culture induced some adaptations, but the Caco-2 cells showed no differences in their abilities to filter and metabolize grape-seed derived extract (GSPE) components. The co-culture clearly reproduced the ability of a procyanidin extract to decrease the triglyceride secretion of hepatocytes, a proven in vivo effect. This system mimics a human physiological system that is useful for assaying the bioactivity of extracts and may be able to be used for developing new functional foods.     

Metabolic pathways of the colonic metabolism of flavonoids (flavonols,flavones and flavanones) and phenolic acids

Flavonoids are metabolized by the gut microflora giving rise to a wide range of phenolic acids that may exert systemic effects in the body. Nevertheless, the colonic metabolism pathways and the function of the metabolites formed are poorly studied. In the present study, the individual colonic metabolism of three subclasses of flavonoids (flavonols, flavones and flavanones) and phenolic acids was evaluated. For this, seven standards of flavonoids (quercetin, quercetin–rhamnoside, quercetin–rutinoside, myricetin, luteolin, naringenin and kaempferol–rutinoside) and two phenolic acids (protocatechuic acid and gallic acid) were submitted to an in vitro fermentation model using rat colonic microflora. Simultaneously, a nuts–cocoa cream enriched with these standards of flavonoids was incubated and the colonic metabolism of these compounds was evaluated. The results showed that the greatest number of colonic metabolites came from the fermentation of quercetin and quercetin–rhamnoside, and the maximum concentration of fermentation products was observed after 48 h of fermentation. On the other hand, a smaller number of fermentation products were observed after the colonic fermentation of kaempferol–rutinoside, naringenin, luteolin and myricetin. The phenolic acids were slightly metabolized by the colonic microflora.     

Distribution of procyanidins and their metabolites in rat plasma and tissues after an acute intake of hazelnut extract

Procyanidins are present in a wide range of dietary foods and their metabolism is well known. Nevertheless, the biological target and their distribution are topics lacking information. The purpose of the present work was to study the metabolism and distribution of procyanidins and their metabolites in rat plasma and different tissues, such as liver, brain, lung, kidney, intestine, testicle, spleen, heart and thymus, after 2 h of an acute intake of hazelnut extract rich in procyanidins (5 g kg(-1) of rat body weight). The interest of an acute intake of procyanidins instead of repeated low doses from daily ingestion of is to achieve a concentration of metabolites in the tissues that allows their detection and quantification. The results showed that catechin and epicatechin-glucuronide, methyl catechin and epicatechin-glucuronide and methyl catechin and epicatechin-sulphate were detected in plasma samples at the μmol level. On the other hand, catechin-glucuronide, methyl catechin-glucuronide and methyl catechin-sulphate were identified in some tissues, such as thymus, intestine, lung, kidney, spleen and testicle at the nmol level. Procyanidins with a low grade of polymerization (dimers and trimers) were detected in plasma samples and the intestine. Additionally, a wide range of simple aromatic acids from fermentation by the colonic microflora was detected in all tissues studied.     

On the use of double-skinned membranes to prevent chemical interaction between membranes and catalysts

This communication summarizes the use of double-skinned membranes for hydrogen separation in presence of TiO₂ based catalyst (PtReCe/TiO₂). The use of this type of membrane avoids the direct contact between catalyst particles and surface of the Pd-based hydrogen selective layer due to the presence of a mesoporous YSZ/γ-Al₂O₃ layer. The PdAg layer is protected by the mesoporous layer from direct contact with catalyst particles, avoiding erosion and possible chemical interactions. In comparison with a conventional PdAg membrane, the hydrogen flux of DS-membrane was observed not to be compromised during test carried out at 400 °C.     

Reactive power pricing: a conceptual framework for remuneration andcharging procedures

A new electrical sector regulation is being implemented in different countries all over the world. The new regulation stresses the role of competitive markets for the procurement and remuneration of ancillary services. Among these services stand the ones associated with reactive power supply and transmission network voltage control in order to maintain the required system security levels. The object of this paper is twofold. On one hand, reactive power supply and voltage control services, which today are bundled, are decomposed in two types: (i) voltage profile management and reactive dispatch, and (ii) voltage regulation. A theoretical approach based on marginal pricing is proposed in order to clarify the principles to remunerate the suppliers and to charge the consumers of these services. On the other hand, a practical organization of reactive supply and voltage service markets is presented to be implemented in a competitive environment     

Unraveling the Interaction between the LPS O‐Antigen of Burkholderia anthina and the 5D8 Monoclonal Antibody by Using a Multidisciplinary Chemical Approach,with Synthesis,NMR, and Molecular Modeling Methods

The interaction between the O‐chain from the lipopolysaccharide from Burkholderia anthina and a lipopolysaccharide‐specific monoclonal antibody (5D8) has been studied at high resolution by NMR spectroscopy. In particular, the 5D8‐bound epitope of the saccharide entity has been unraveled by a combination of saturation transfer difference (STD) and transferred NOESY (tr‐NOESY) experiments performed on the 5D8/polysaccharide complex. To dissect the fine details of the molecular recognition events, further experiments with simpler carbohydrate ligands were carried out. Thus, experiments were also performed with ad hoc synthesized trisaccharide and hexasaccharide O‐antigen repeating units. By using this multidisciplinary approach (chemical synthesis, NMR spectroscopy and molecular dynamics simulation), determination of the binding epitope and the contribution to the binding of the sugar units composing the O‐chain have been determined.     

Chemistry and Biology of the Potent Endotoxin from a Burkholderia dolosa Clinical Isolate from a Cystic Fibrosis Patient

This is the first report of the chemical and biological properties of the lipooligosaccharide (LOS) endotoxin isolated from Burkholderia dolosa IST4208, an isolate recovered from a cystic fibrosis (CF) patient in a Portuguese CF center. B. dolosa is a member of the Burkholderia cepacia complex, a group of closely related species that are highly problematic and opportunistic pathogens in CF. B. dolosa infection leads to accelerated loss of lung function and decreased survival. The structural determination of its endotoxin was achieved using a combination of chemistry and spectroscopy, and has revealed a novel endotoxin structure. The purified LOS was tested for its immunostimulatory activity on human HEK 293 cells expressing TLR‐4, MD‐2, and CD‐14. In these assays, the LOS showed strong proinflammatory activity.     

Application of barcoding to Amazonian commercial fish labelling

Methods for seafood authentication are increasingly demanded in food sciences. In this study we have detected mislabelling for eight out of 22 Amazonian fish species in two Brazilian markets, employing species-specific DNA markers. Mislabelling was most likely due to inadvertent errors in fish classification. These results emphasize the convenience of applying DNA methodology for seafood authentication.