Morphometry and morphology of fish otoliths on the coast of the state of Maranhão, Brazil.

The main objective of this study was to evaluate the biometric relationships between the species Bagre bagre, Lutjanus synagris and Nebris microps and their otoliths. The relationship between the size of the otolith (length and weight) and the size of the fish (standard length and total weight) was determined using the linear regression model (y = a + bx). For the morphological description, the otoliths of three specimens were selected by standard length class (10mm). The morphological characters analyzed were chosen according to traditional literature. Three hundred eight specimens of B. bagre, 200 of L. synagris and 237 of N. microps were analyzed. Throughout the collection period, the source of the capture of individuals was the municipality of Raposa. The linear correlations for fish and otolith length for B. bagre were 0.9129 and 0.9652, respectively. For L. synagris, the coefficients were 0.8634 and 0.8672, while for N. microps, 0.9597 and 0.8636, respectively. The morphological classification of L. synagris and N. microps is of the Saggita type, and the B. bagre species is of the Lapillus type. From the data presented here, it is possible to observe that otolith morphometric and morphological data can serve as a parameter to estimate the relationship between the fish and the otolith in terms of its biomass and the length of an individual and a population.

Crystallization and preliminary X-ray crystallographic analysis of the heterodimeric crotoxin complex and the isolated subunits crotapotin and phospholipase A2.

Crotoxin, a potent neurotoxin from the venom of the South American rattlesnake Crotalus durissus terrificus, exists as a heterodimer formed between a phospholipase A(2) and a catalytically inactive acidic phospholipase A(2) analogue (crotapotin). Large single crystals of the crotoxin complex and of the isolated subunits have been obtained. The crotoxin complex crystal belongs to the orthorhombic space group P2(1)2(1)2, with unit-cell parameters a = 38.2, b = 68.7, c = 84.2 A, and diffracted to 1.75 A resolution. The crystal of the phospholipase A(2) domain belongs to the hexagonal space group P6(1)22 (or its enantiomorph P6(5)22), with unit-cell parameters a = b = 38.7, c = 286.7 A, and diffracted to 2.6 A resolution. The crotapotin crystal diffracted to 2.3 A resolution; however, the highly diffuse diffraction pattern did not permit unambiguous assignment of the unit-cell parameters.

Antiatherogenic effects of S-nitroso-N-acetylcysteine in hypercholesterolemic LDL receptor knockout mice.

BACKGROUND: The pathophysiology of the NO/NO synthase system and dysfunctional changes in the endothelium in the early phases of the atherogenic process are incompletely understood. In this study, we investigated the effects of the nitrosothiol NO donor S-nitroso-N-acetylcysteine (SNAC) in the early prevention of plaque development in the hypercholesterolemic LDLr-/- mice as well as the changes in endothelium-dependent relaxation and NO synthase expression. METHODS AND RESULTS: LDLr-/- mice were fed a 1.25% cholesterol-enriched diet for 15 days. Plasma cholesterol/triglyceride levels increased and this increase was accompanied by the development of aortic root lesions. Aortic vasorelaxation to acetylcholine was increased, although endothelium-independent relaxation in response to sodium nitroprusside did not change, which suggest stimulated NO release enhanced. This dysfunction was associated with enhanced aortic superoxide production and with increased levels of constitutive NOS isoform expression, particularly neuronal NOS. SNAC (S-nitroso-N-acetylcysteine) administration (0.51 micromol/kg/day i.p. for 15 days) decreased the extent of the plaque by 55% in hypercholesterolemic mice, but had no effects on vasomotor changes. It did, however, lead to a decrease in constitutive NOS expression. The SNAC induced only minor changes in plasma lipid profile. CONCLUSION: The present study has shown that, in early stages of plaque development in LDLr-/- mice, specific changes in NO/NO synthase system develop, that are characterized by increased endothelium-dependent vasorelaxation and increased constitutive NOS expression. Since the development of plaque and the indicator of endothelial cell dysfunction were prevented by SNAC, such treatment may constitute a novel strategy for the halting of progression of early plaque.

The prima donna of epigenetics: the regulation of gene expression by DNA methylation

This review focuses on the mechanisms of DNA methylation, DNA methylation pattern formation and their involvement in gene regulation. Association of DNA methylation with imprinting, embryonic development and human diseases is discussed. Furthermore, besides considering changes in DNA methylation as mechanisms of disease, the role of epigenetics in general and DNA methylation in particular in transgenerational carcinogenesis, in memory formation and behavior establishment are brought about as mechanisms based on the cellular memory of gene expression patterns.

The prima donna of epigenetics: the regulation of gene expression by DNA methylation.

This review focuses on the mechanisms of DNA methylation, DNA methylation pattern formation and their involvement in gene regulation. Association of DNA methylation with imprinting, embryonic development and human diseases is discussed. Furthermore, besides considering changes in DNA methylation as mechanisms of disease, the role of epigenetics in general and DNA methylation in particular in transgenerational carcinogenesis, in memory formation and behavior establishment are brought about as mechanisms based on the cellular memory of gene expression patterns.

Hypolipidaemic effects of naringenin, rutin, nicotinic acid and their associations.

Atherosclerosis can be defined as being a disease of coronary circulation. The present work evaluates the action of the naringenin, rutin, nicotinic acid, isolated and in association, on the metabolism of lipids. Cholesterol, cholesterol HDL, and triacylglycerols have been dosed after retreat of blood, following the administration of the compounds dissolved in propylene glycol by intraperitoneal route in doses of 5 mg kg-1 body wt. Results evidence that naringenin and nicotinic acid, isolated as well as their association with naringenin and nicotinic acid-rutin, present the largest percentual reduction of cholesterol. On the other hand, the best results for cholesterol-HDL have been obtained with naringenin, while rutin has shown the best triacylglycerols levels.

Efeitos das associaçöes de morina-ácido nicotínico e quercetina-ácido nicotínico no controle de lipídeos / Effects of the associations of morin-nicotinic acid and quercetin-nicotinic acid in the lipidic control

A aterosclerose pode ser considerada uma doença na circulaçäo coronariana. O presente trabalho estuda a açÄo da quercetina, morina, ácido nicotínico de maneira isolada e em associaçÄo envolvendo quercetina + ácido nicotínico e morina + ácido nicotínico no metabolismo lipídico. Foram dosados colesterol, colesterol-HDL e triacilglicerol após administraçäo de duas doses dos compostos morina, quercetina, morina + ácido nicotínico e quercetina + ácido nicotínico sendo a primeira imediatamente após a administraçäo do triton e a segunda dose, vinte horas depois. Decorridos quarenta e três horas após a administraçäo do triton o sangue foi analisado. Os resultados mostraram que morina + ácido nicotínico e quercetina + ácido nicotínico apresentaram os melhores resultados para colesterol (-83,77 porcento e 74,42 porcento). Para colesterol-HDL os melhores resultados foram com morina e com associaçäo quercetina + ácido nicotínico (+17,99 porcento e +21,96 porcento). Morina + ácido nicotínico mostraram os melhores níveis para triacilgliceróis (-83,77 porcento)