Chronic stress differentially affects antioxidant enzymes and modifies the acute stress response in liver of wistar rats.

Summary Clinical reports suggest close interactions between stressors, particularly those of long duration, and liver diseases, such as hepatic inflammation, that is proposed to occur via reactive oxygen species. In the present study we have used 21-day social isolation of male Wistar rats as a model of chronic stress to investigate protein expression/activity of liver antioxidant enzymes: superoxide dismutases (SODs), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GLR), and protein expression of their upstream regulators: glucocorticoid receptor (GR) and nuclear factor kappa B (NFkB). We have also characterized these parameters in either naive or chronically stressed animals that were challenged by 30-min acute immobilization. We found that chronic isolation caused decrease in serum corticosterone (CORT) and blood glucose (GLU), increase in NFkB signaling, and disproportion between CuZnSOD, peroxidases (CAT, GPx) and GLR, thus promoting H 2 O 2 accumulation and prooxidative state in liver. The overall results suggested that chronic stress exaggerated responsiveness to subsequent stressor at the level of CORT and GLU, and potentiated GLR response, but compromised the restoration of oxido-reductive balance due to irreversible alterations in MnSOD and GPx

Aloe barbadensis: how a miraculous plant becomes reality

Aloe barbadensis Miller is a plant that is native to North and East Africa and has accompanied man for over 5,000 years. The aloe vera plant has been endowed with digestive, dermatological, culinary and cosmetic virtues. On this basis, aloe provides a range of possibilities for fascinating studies from several points of view, including the analysis of chemical composition, the biochemistry involved in various activities and its application in pharmacology, as well as from horticultural and economic standpoints. The use of aloe vera as a medicinal plant is mentioned in numerous ancient texts such as the Bible. This multitude of medicinal uses has been described and discussed for centuries, thus transforming this miracle plant into reality. A summary of the historical uses, chemical composition and biological activities of this species is presented in this review. The latest clinical studies involved in vivo and in vitro assays conducted with aloe vera gel or its metabolites and the results of these studies are reviewed

Detection of irradiated food by the changes in protein molecular mass distribution

Protein constituents were extracted from chicken drumstick and chicken white meat, separated according to the molecular mass (Mm), using discontinuous SDS-polyacrylamide electrophoresis (SDS-PAGE) and quantified by scanning densitometry. The obtained profiles were compared with the profiles corresponding to the meat samples which were irradiated at -20. +4, and +20 degrees c. It was observed that the irradiation of chicken while meat led to protein scission which was partially unselective (e.g. the amount of proteins whose Mm GT 20 kDa decreased, while the amount of those whose Mm LT 20 kDa increased), and partially selective (e.g, the appearance of Mm congruent to 16 kDa fragment). In the case of chicken drumstick meat the irradiation caused both protein scission and protein crosslinking (unselective and selective, and appearance of 16 kDa fragment). However, in the case of aerated dehydrated egg white proteins, irradiation led only to unselective protein scission. The obtained results are discussed in view of possible application of discontinuous analytical SDS-PAGE combined with laser scanning densitometry for detection of previously irradiated foodstuff. (C) 1999 Elsevier Science Ltd. All rights reserved.9th Tihany Symposium on Radiation Chemistry, Aug 29-Sep 03, 1998, Tatabanya, Hungar

Antioxidant Enzymes Expression and Activity in Liver of Stressed Wistar Rat

Altered activities of antioxidant defence system enzymes and the levels of free radicals scavengers have been found to correlate with various physiological or pathological conditions, including stress. The aim of this study was to determine the effects of chronic 21 day isolation stress on antioxidant enzymes (AOEs) expression and activity in Wistar rat liver tissue. The serum corticosterone (CORT) and glucose (GLU) levels were also measured, as one of the most important indicators of stress. Our data revealed that in chronic stress conditions, when both CORT and GLU were low, the AOEs expression was markedly induced. This increase in MnSOD, CuZnSOD, and catalase exhibited similar trend implying efficient detoxification of O(2) radical anion and H(2)O(2). However, this trend was not followed by the respective enzyme activity. While the total SOD activity was induced by the stress, catalase activity remained unaltered. This discrepancy led us to a conclusion that chronic isolation stress may cause oxidant-antioxidant imbalance in rat liver tissue, favoring H(2)O(2) accumulation.9th International Conference on Fundamental and Applied Aspects of Physical Chemistry, Sep 24-26, 2008, Belgrade, Serbi

Contributions of counter-charge in a potassium channel voltage-sensor domain

Voltage-sensor domains couple membrane potential to conformational changes in voltage-gated ion channels and phosphatases. Highly co-evolved acidic and aromatic side-chains assist the transfer of cationic side-chains across the transmembrane electric field during voltage-sensing. We investigated the functional contribution of negative electrostatic potentials from these residues to channel gating and voltage-sensing with unnatural amino acid mutagenesis, electrophysiology, voltage-clamp fluorometry and ab initio calculations. The data show that neutralization of two conserved acidic side-chains in transmembrane segments S2 and S3, Glu293 and Asp316 in Shaker potassium channels, have little functional effect on conductance-voltage relationships, although Glu293 appears to catalyze S4 movement. Our results suggest that neither Glu293 nor Asp316 engages in electrostatic state-dependent charge-charge interactions with S4, likely because they occupy, and possibly help create, a water-filled vestibule

Contributions of counter-charge in a potassium channel voltage-sensor domain

Povećane energetske potrebe trudnica može nadoknaditi konzumacijom mlijeka i namirnica koje sadrže esencijalne masne kiseline, aminokiseline, minerale i vitamine. Zbog velike kalorijske vrijednosti namirnice poput orašastih plodova, suhog voća, te namazi na bazi orašida zadovoljit će dnevno povećanje kalorija, ali i unos kvalitetnih nutrijenata. Preporučene masnoće u trudnoći su ulja dobivena hladnim prešanjem kao npr. bučino ulje, maslinovo ili ulje kukuruznih klica. Održavanje tjelesne aktivnosti za vrijeme trudnoće način je pripreme organizma za porod, te se postiže pozitivan učinak na raspoloženje trudnice. Dojilje svoju prehranu baziraju na raznovrsnoj hrani, a praćenjem reakcije djeteta dobivaju uvid utječe li na dijete određena namirnica

Superoxide dismutase activity in various fractions of full bovine milk

Specific composition, protein profiles and total SOD activity were analysed in full milk samples obtained from five farms of the Milk Company IMPAZ The effects of several laboratory treatments on milk proteins SDS-PAGE profiles and the respective SOD activity were also followed. The total SOD activity was detected in all full milk samples, and its values varied between 2 and 3 U mg(-1) protein. The enzyme could be partially purified, up to approximate to 5 U mg(-1) protein, by ethanol extraction. The recovered SOD activity in ethanol extract was proportional to the initial full milk SOD activity. The disruption of casein micelles by Ca2+ removal was followed by a significant decrease in SOD activity to 1.24-0.18 U mg(-1) protein. The loss of enzyme activity was ascribed to the changes in milk milieu induced by dissociation of casein micelles