Lipase and esterase: to what extent can this classification be applied accurately?

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Genotoxic, mutagenic and cytotoxic effects of the commercial dye CI Disperse Blue 291 in the human hepatic cell line HepG2

Textile dyes are discarded into the aquatic ecosystem via industrial effluents and potentially expose humans and local biota to adverse effects. The commercial dye CI Disperse Blue 291 which contains the aminoazobenzene 2-[(2-bromo-4,6-dinitrophenyl)azo]-5(diethylamino)-4-methoxyacetanilide (CAS registry no. 56548-64-2), was tested for genotoxicity and cytotoxicity in the human hepatoma cell line HepG2, using the comet assay, micronucleus (MN) test and a cell viability test. Five different concentrations of the test compound were examined: 200 mu g/ml, 400 mu g/ml, 600 mu g/ml, 800 mu g/ml and 1000 mu g/ml. An increase in comet tail length and in the frequency of MN was detected with exposure of cells to concentrations of the commercial dye from 400 pg/ml. Furthermore, the dye was found to decrease cell viability. The results of this study demonstrate for the first time the genotoxic and mutagenic effects of the dye CI Disperse Blue 291 in mammalian cells, thus stressing the need to develop non-mutagenic dyes and to invest in improving the treatment of effluents. These measures will help to prevent harmful effects that these compounds can have on humans and aquatic organisms that come in contact with them. (C) 2007 Elsevier Ltd. All rights reserved.

Investigation of cytotoxic, apoptosis-inducing, genotoxic and protective effects of the flavonoid rutin in HTC hepatic cells

Rutin is a flavonoid with antioxidant, vasodilatory, anti-inflammatory and immune-stimulating activities. To study the toxicity of rutin and its protective effect, this work investigated the cytotoxic, apoptosis-inducing, genotoxic and protective effects of rutin in HTC cells. In the MTT assay, the highest concentration tested (810 mu M) showed cytotoxicity after 72 h of treatment, where cell viability and cell proliferation was diminished. None of the concentrations of rutin tested induced apoptosis after 24 h treatment. The highest concentration of rutin after 24 h treatment induced DNA damage, shown in the comet assay, but did have a genotoxic effect in the micronucleus test. Rutin was tested against the pro-carcinogenic agent benzo(a)pyrene, at concentrations of 90, 270 and 810 mu M, and was found to reduce induced DNA damage significantly. This protective effect of rutin against a pro-carcinogen, suggests an important biological activity for this compound, which can contribute to human health through the diet. (C) 2010 Elsevier GmbH. All rights reserved.

Protective effects of beta-glucan extracted from barley against benzo[a]pyrene-induced DNA damage in hepatic cell HepG2

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Exercise and spirulina control non-alcoholic hepatic steatosis and lipid profile in diabetic Wistar rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Dietary restriction, caloric value and the accumulation of hepatic fat

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Role of the post-hepatic septum on breathing during locomotion in Tupinambis merianae (Reptilia : Teiidae)

Tupinambis merianae increased minute ventilation by increasing both tidal volume and breathing frequency during sustained locomotion at 0.17 m s(-1). Animals in which the post-hepatic septum (PHS) had been surgically removed were not able to increase tidal volume during locomotion. Tegus without PHS compensated, in part, by increasing breathing frequency above the levels observed for tegus with intact PHS, but minute ventilation remained less than in the control animals. The rate of oxygen consumption and the air convection requirement, however, were not significantly different between animals with and without PHS, nor at the tested speeds was endurance affected by the removal of the PHS. These data suggest that the PHS facilitates ventilation by acting as a mechanical barrier, preventing the viscera from moving cranially during physical exertion.

Synergistic effect in the catalytic activity of lipase Rhizomucor miehei immobilized on zeolites for the production of biodiesel

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of surfactants and polyethylene glycol on the activity and stability of a lipase from oilseeds of Pachira aquatica

Lipases from oilseeds have a great potential for commercial exploration as industrial enzymes. Lipases are used mixed with surfactants in cleaning and other formulated products, and accordingly, both components must be compatible with each other. This work presents the results of the effects of anionic, cationic and nonionic surfactants, polyethylene glycol and urea on the activity and stability of a lipase extracted of oilseeds from Pachira aquatica. The enzyme was purified and the spectrophotometric assays were done using p-nitrophenyl acetate (p-NPA) as substrate pH 7.5 and 25 degrees C. The activity was significantly enhanced by the cationic surfactant CTAB. Bile salts increased the lipase activity in the tested concentration range, whereas anionic and nonionic surfactants showed an inhibitory effect. Aqueous solutions of PEG activated the lipase and maximum activation (161%) occurred in PEG 12,000. This effect on lipase that can be due to exposition of some hydrophobic residues located in the vicinity of the active site or aggregation.

A new lipase isolated from oleaginous seeds from Pachira aquatica (Bombacaceae)

A new lipase from seeds of Pachira aquatica was purified to homogeneity by SDS-PAGE obtaining an enzyme with a molecular weight of approximately 55 kDa. The purified lipase exhibited maximum activity at 40 degrees C and pH 8.0, for an incubation time of 90 min. Concerning temperature stability, at the range from 4 to 50 degrees C, it retained approximately 47% of its original activity for 3 h. The enzyme activity increased in the presence of Ca(++) and Mg(++), but was inhibited by Hg(++), Mn(++), Zn(++), Al(+++) and various oxidizing and reducing agents. The lipase was highly stable in the presence of organic solvents, and its activity was stimulated by methanol. The values of K(m) and V(max) were 1.65 mM and 37.3 mu mol mL(-1) min(-1), respectively, using p-nitrophenylacetate as substrate. The enzyme showed preference for esters of long-chain fatty acids, but demonstrated significant activity against a wide range of substrates.

Influence of tetracycline in the hepatic and renal development of rat's offspring

O objetivo deste estudo foi avaliar os possíveis efeitos da tetraciclina administrada a ratas, no décimo dia de gestação, no desenvolvimento hepático e renal de seus filhotes. O fígado mostrou vacuolização, necrose, inflamação e dilatação sinusoidal mais evidente em recém-nascidos. Mitoses, aumento precoce da população de células de Kupffer e hipertrofia de hepatócitos com maior síntese de glicogênio estavam presentes no décimo e vigésimo dias de vida. O rim mostrou vacuolização tubular e necrose discretas, mais evidentes nos recém-nascidos, assim como sinais de regeneração tubular no décimo e vigésimo dias. Esses resultados sugeriram que os órgãos estudados sofreram alterações morfológicas transitórias durante o desenvolvimento, mas apresentaram sinais de regeneração ao longo dos primeiros dias de vida.

The effect of gastric dilatation in rats submitted to gasified water ingestion under the hepatic metabolic function

INTRODUÇÃO: O excesso de peso na população aumentou de forma significante nas últimas décadas e as bebidas gasosas tornaram-se um fator ambiental importante no comportamento alimentar das pessoas, sendo os EUA, México e Brasil, nesta ordem, os três maiores paises produtores e consumidores de refrigerantes. OBJETIVO: Investigar os efeitos da dilatação gástrica em ratos submetidos a ingestão de água gaseificada, veículo uniforme para todos os refrigerantes, sobre parâmetros metabólicos da função hepática. MÉTODOS: Foram constituídos dois grupos de 15 ratos acompanhados por 15 semanas. Ao Grupo-I, foram oferecidos 200 g/dia de ração ad libitum e 100 ml de água não gaseificada em 3 períodos diários, ao Grupo-II, foram oferecidos 200 g/dia de ração ad libitum e 100 ml de água gaseificada em 3 períodos diários; em cada grupo,foram calculados a média (x) e o desvio padrão (s); para todos os atributos estudados foi utilizado o método estatístico de teste t pareado, comparando-se GI com GII, testando-se o efeito dos tipos de água. RESULTADOS: Os resultados identificaram que os animais que foram submetidos ao tratamento com água gaseificada (Grupo-II), apresentaram um aumento de transaminase glutâmica pirúvica (TGP) e fosfatase alcalina p<0,01), tendência de aumento da transaminase glutâmica oxalacética (TGO) (0,10>p>0,05) e aumento da área gástrica com alterações morfológicas macroscópicas como o desaparecimento do pregueamento mucoso característico. CONCLUSÃO: A água gaseificada favoreceu o aumento da área gástrica com conseqüente desaparecimento macroscópico do pregueamento mucoso do órgão, que ocasionou alterações metabólicas da função hepática.