Cross-linking methionine and amine residues with reactive halogen species.

Irreversible cross-links are increasingly being recognized as important posttranslational oxidative protein modifications that contribute to tissue injury during oxidative stress and inflammation. They also have a structural function in extracellular matrix proteins such as collagen IV. Likely contenders for forming such cross-links are the reactive halogen species that are generated by neutrophils and eosinophils, including hypochlorous acid, hypobromous acid, and their related haloamines.

Peroxynitrite-mediated alpha-tocopherol oxidation in low-density lipoprotein: a mechanistic approach.

Previous reports proposed that peroxynitrite (ONOO-) oxidizes alpha-tocopherol (alpha-TOH) through a two-electron concerted mechanism. In contrast, ONOO- oxidizes phenols via free radicals arising from peroxo bond homolysis. To understand the kinetics and mechanism of alpha-TOH and gamma-tocopherol (gamma-TOH) oxidation in low-density lipoprotein (LDL) (direct vs.

In vitro effects of D-2-hydroxyglutaric acid on glutamate binding, uptake and release in cerebral cortex of rats.

Neurological dysfunction is common in patients with D-2-hydroxyglutaric aciduria (DHGA). However, the mechanisms underlying the neuropathology of this disorder are far from understood. In the present study, we investigated the in vitro effects of D-2-hydroxyglutaric acid (DGA) at various concentrations (0.

The role of glutathione in yeast dehydration tolerance.

Among the factors that affect cell resistance against dehydration, oxidation is considered to be of great importance. In this work, we verified that both control and glutathione deficient mutant strains were much more oxidized after dehydration. Moreover, cells lacking glutathione showed a twofold higher increase in oxidation and lipid peroxidation than the control strain.

Active and inactive ecto-5'-nucleotidase variants in liver of control and dystrophic Lama2dy mice.

The ecto-5'-nucleotidase (eNT) activity and the eNT protein content in liver of normal and merosin-deficient dystrophic Lama2dy mice were studied. After the solubilization procedure, the eNT activity in the final extract was 9.2+/-2.

Ecto-nucleotidase activities in spinal cord of rats changes as function of age.

An increase in ADP hydrolysis was observed in spinal cord synaptosomal fractions of 2-month-old Wistar male rats, when compared to other ages (1, 4 and 6 months of age), while no change in ATPase activity was observed. Conversely, in female rats, whilst no change in ADPase activity was observed in the spinal cord synaptosomal fraction, ATPase activity diminished with age, in 1-6-month-old animals. 5'-Nucleotidase activity was higher in the 4-month-old male and female rats in relation to 1 and 2-month-old animals.

Mechanisms of esophageal cancer development in Brazilians.

Esophageal cancer represents one of the most common and lethal cancers around the World. Some areas of South America, including parts of Brazil, present the highest incidence of the disease in the West. The main etiological factors that have been associated with the disease in Brazil are alcohol consumption, tobacco smoking and, in the South, consumption of hot maté.

Inhibition of brain energy metabolism by the alpha-keto acids accumulating in maple syrup urine disease.

Neurological dysfunction is a common finding in patients with maple syrup urine disease (MSUD). However, the mechanisms underlying the neuropathology of brain damage in this disorder are poorly known. In the present study, we investigated the effect of the in vitro effect of the branched chain alpha-keto acids (BCKA) accumulating in MSUD on some parameters of energy metabolism in cerebral cortex of rats.

Evaluation of the effect of chronic administration of drugs on rat behavior in the water maze task.

Tissue accumulation of intermediates of the metabolism occurs in various inherited neurodegenerative disorders, including methylmalonic acidemia (MA). Animal cognition is usually tested by measuring learning/memory of rats in behavioral tasks. A procedure in which rats are chronically injected with the metabolites accumulating in the neurometabolic disorder methylmalonic acidemia from the 5th to the 28th day of life is described.

Inflammatory responses induced in mice by lectin from Talisia esculenta seeds.

A novel lectin from Talisia esculenta seeds (TEL) has recently been purified and characterized. In this study we investigated the proinflammatory activity of TEL in mice using both the air-pouch and peritoneal cavity as well as paw oedema models. TEL (10-40 microg) induced significant neutrophil and mononuclear cell recruitment when injected into either mouse air-pouch or peritoneal cavity.

Effect of an acidic heteropolysaccharide (ARAGAL) from the gum of Anadenanthera colubrina (Angico branco) on peritoneal macrophage functions.

Brazilian flora are a source of interesting polysaccharides which, either in their native state or when submitted to structural modifications, might have potential applications as biological response modifiers (BRM). A complex acidic heteropolysaccharide, containing mainly galactose and arabinose (ARAGAL), isolated from the gum of the native leguminous tree Anadenanthera colubrina (Angico branco), was studied for its immunological properties on peritoneal exudate cells, namely their superoxide anion production, phagocytic activity, morphological alterations and percentage content of activated macrophages. Activation of macrophages showing increased cytoplasm, bright and large nuclei, various cytoplasmatic projections and spreading ability, was detected following in vitro cell exposure to ARAGAL or in cells obtained from treated animals.

Production of the active antifungal Pisum sativum defensin 1 (Psd1) in Pichia pastoris: overcoming the inefficiency of the STE13 protease.

Plant defensins are small cysteine-rich proteins that present high activity against fungi and bacteria and inhibition of insect proteases and alpha-amylases. Here, we present the expression in Pichia pastoris, purification and characterization of the recombinant Pisum sativum defensin 1(rPsd1); a pea defensin which presents four disulfide bridges and high antifungal activity. For this, we had to overcome the inefficiency of the STE13 protease.

CHECKDEN: a computer program to generate 1D, 2D and 3D grids of functions dependent on the molecular ab initio electron density.

A program to compute many functions dependent on the electron density rho(r) from the results of ab initio molecular calculations is presented. The program allows the generation of different one-, two-, and three-dimensional grids for further graphical representation or numerical analysis. Other options like extracting separate atom contributions to the function computed or locating maximum and minimum values are also implemented.

Comparative studies of the polysaccharides from species of the genus Ramalina-lichenized fungi-of three distinct habitats.

Several structurally different glucans (alpha- and beta-) and galactomannans were characterized as components of four species of the genus Ramalina, namely R. dendriscoides, R. fraxinea, R.

Maize tonoplast PP(i)-dependent H(+)/Ca(2+) exchange: two K(s) for Ca(2+) and inhibition by thapsigargin.

Maize root tonoplasts are able to accumulate Ca(2+) using the energy derived from the H(+) gradient formed during PP(i) hydrolysis. Oxalate increases 6- to 10-fold the amount of Ca(2+) accumulated by tonoplast. Two apparently different K(s) values for Ca(2+) with values of 0.

Complexes of sodium vanadate(V) with methyl alpha-D-mannopyranoside, methyl alpha- and beta-D-galactopyranoside, and selected O-methyl derivatives: a 51V and 13C NMR study.

The hydroxyl group stereochemistry of complexation of sodium vanadate(V) with Me alpha-Manp, Me alpha- and beta-Galp and selected O-methyl derivatives in D(2)O was determined by 51V, 1D and 2D 13C NMR spectroscopy at pD 7.8. The 51V approach served to show the extent of complexation and the minimum number of esters formed.

Structural, enzymatic and biological properties of new PLA(2) isoform from Crotalus durissus terrificus venom.

We isolated a new PLA(2) from the Crotalus durissus terrificus venom that designated F15, which showed allosteric behavior with a V(max) of 8.5nmol/min/mg and a K(m) of 38.5 mM.

Characterization of a type I regulatory subunit of cAMP-dependent protein kinase from the bivalve mollusk Mytilus galloprovincialis.

Two isoforms of the regulatory subunit (R) of cAMP-dependent protein kinase (PKA), named R(myt1) and R(myt2), had been purified in our laboratory from two different tissues of the sea mussel Mytilus galloprovincialis. In this paper, we report the sequences of several peptides obtained from tryptic digestion of R(myt1). As a whole, these sequences showed high homology with regions of type I R subunits from invertebrate and also from mammalian sources, but homology with those of fungal and type II R subunits was much lower, which indicates that R(myt1) can be considered as a type I R isoform.

Neuroprotective effect of ebselen on rat hippocampal slices submitted to oxygen-glucose deprivation: correlation with immunocontent of inducible nitric oxide synthase.

Ebselen is a seleno organic compound with antioxidant and anti-inflammatory properties, which is under clinical trials for the treatment of ischemic stroke. In this study, we attempted to correlate the protective effects of ebselen and the inducible nitric oxide synthase (iNOS) immunocontent in hippocampal slices submitted to oxygen-glucose deprivation (OGD), since the exacerbated production of nitric oxide by iNOS plays a role in the mechanisms of cellular death in ischemic insults. Ebselen (10 microM) protected slices from the deleterious effects of OGD (as assessed by MTT assay) only when present during all the recovery period (180 min).

Neonatal hypoxia-ischemia reduces ganglioside, phospholipid and cholesterol contents in the rat hippocampus.

Hypoxia-ischemia is a common cause of neonatal brain damage producing serious impact on cerebral maturation. This report demonstrates that rats submitted to hypoxia-ischemia present a marked decrease in hippocampal gangliosides, phospholipids and cholesterol contents as from 7 days after the injury. Although chromatographic profiles of the different ganglioside species (GM1, GD1a, GD1b, and GT1b) from the hippocampus of hypoxic-ischemic hippocampi groups (HI) were apparently unaffected, as compared with controls, there were quantitative absolute reductions in HI.

Mosquito embryos and eggs: polarity and terminology of chorionic layers.

The development of genetically modified vectors refractory to parasites is seen as a promising strategy in the future control of endemic diseases such as malaria. Nevertheless, knowledge of mosquito embryogenesis, a pre-requisite to the establishment of transgenic individuals, has been presently neglected. We have here studied the eggs from two neotropical malaria vectors.

Secretion of beta-glycosidase by middle midgut cells and its recycling in the midgut of Tenebrio molitor larvae.

There are four beta-glycosidases (betagly1, betagly2, betagly3, and betagly4) in Tenebrio molitor midgut larvae. betagly1 and betagly2 have identical kinetic properties, and differ in a few amino acid residues. Purified betagly1 was used to raise antibodies in a rabbit.

Comparative cytotoxicity of dimethylamide-crotonin in the promyelocytic leukemia cell line (HL60) and human peripheral blood mononuclear cells.

Dehydrocrotonin (DHC) is a diterpene lactone obtained from Croton cajucara (Sacaca). Dimethylamide-crotonin (DCR), a DHC derivative, has a similar inhibitory effect on leukemic HL60 cells than its parent compound evaluated by different endpoints of cytotoxicity. No cytotoxicity or morphological alterations associated with apoptosis were detected in human peripheral blood mononuclear cells (PBMC) after treatment with up to 400 micro M DCR in presence of phytohemaglutinin (5 micro g/ml).

The gene encoding glutathione-dependent formaldehyde dehydrogenase/GSNO reductase is responsive to wounding, jasmonic acid and salicylic acid.

It has recently been discovered that glutathione-dependent formaldehyde dehydrogenase (FALDH) exhibits a strong S-nitrosoglutathione reductase activity. Plants use NO and S-nitrosothiols as signaling molecules to activate defense mechanisms. Therefore, it is interesting to investigate the regulation of FALDH by mechanical wounding and plant hormones involved in signal transduction.

Development of an ELISA approach for the determination of flavodoxin and ferredoxin as markers of iron deficiency in phytoplankton.

Quantification of the iron-nutritional status of phytoplankton is of great interest not only for the study of oceans but also for fresh waters. Flavodoxin is a small flavoprotein proposed as a marker for iron deficiency, since it is induced as a consequence of iron deprivation, replacing the iron-sulphur protein ferredoxin. Flavodoxin and ferredoxin have been frequently used as markers for determination of iron deficiency in phytoplankton.