Interleukin-15 augments oxidative metabolism and fungicidal activity of human monocytes against Paracoccidioides brasiliensis

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

Interleukin-15 increases Paracoccidioides brasiliensis killing by human neutrophils

Interleukin-15 is a cytokine produced by a wide range of different cell types, including macrophages, in response to lipopolysaccharide or microbial infection. This cytokine may play a crucial role in the activation of phagocytic cells against pathogens, especially during innate immune response. The effects of IL-15 on human polymorphonuclear leukocyte fungicidal activity against a highly virulent Paracoccidioides brasiliensis strain were investigated. Pretreatment of human neutrophils from healthy individuals with IL-15 for IS h increased cell fungicidal activity in a dose-dependent manner. In addition, the exposure to IL-15 induced an increase in neutrophil oxidative burst as evaluated by superoxide anion and H(2)O(2) release. Catalase inhibited fungicidal activity supporting a role for H(2)O(2) in fungus killing. In contrast, IL-8 and TNF-alpha levels were not affected by IL-15 suggesting that its effects were not mediated by these cytokines. Together, these results show that IL-15 is a potent stimulant of antifungal activities in human neutrophils, at least in part by a mechanism dependent on oxidative metabolism. (c) 2007 Elsevier Ltd. All rights reserved.

Green Brazilian propolis action on macrophages and lymphoid organs of chronically stressed mice

Stress is a generic term that summarizes how psychosocial and environmental factors influence physical and mental well-being. The interaction between stress and immunity has been widely investigated, involving the neuroendocrine system and several organs. Assays using natural products in stress models deserve further investigation. Propolis immunomodulatory action has been mentioned and it has been the subject of scientific investigation in our laboratory. The aim of this study was to evaluate if and how propolis activated macrophages in BALB/c mice submitted to immobilization stress, as well as the histopathological analysis of the thymus, bone marrow, spleen and adrenal glands. Stressed mice showed a higher hydrogen peroxide (H2O2) generation by peritoneal macrophages, and propolis treatment potentiated H2O2 generation and inhibited nitric oxide (NO) production by these cells. Histopathological analysis showed no alterations in the thymus, bone marrow and adrenal glands, but increased germinal centers in the spleen. Propolis treatment counteracted the alterations found in the spleen of stressed mice. New research is being carried out in order to elucidate propolis immunomodulatory action during stress.

Protective effects of beta-glucan extracted from Agaricus brasiliensis against chemically induced DNA damage in human lymphocytes

beta-Glucans (BGs) are polysaccharides that are found in the cell walls of organisms such as bacteria, fungi, and some cereals. The objective of the present study was to investigate the genotoxic and antigenotoxic effects of BG extracted from the mushroom Agaricus brasiliensis (=Agaricus blazei Murrill ss. Heinemann). The mutagenic activity of BG was tested in single-cell gel electrophoresis assays with human peripheral lymphocytes. In addition, the protective effects against the cooked food mutagen 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) and (+/-)-anti-B[a]P-7,8-dihydrodiol-9,10-epoxide (BPDE), which is the main metabolite of B[a]P, and against ROS (H2O2)-induced DNA damage, were studied. The results showed that the compound itself was devoid of mutagenic activity, and that a significant dose-dependent protective effect against damage induced by hydrogen peroxide and Trp-P-2 occurred in the dose range 20-80 mu g/ml. To investigate the prevention of Trp-P-2-induced DNA damage, a binding assay was carried out to determine whether BG inactivates the amine via direct binding. Since no such interactions were observed, it is likely that BG interacts with enzymes involved in the metabolism of the amine.

Peroxidase activity in Malpighian tubules of Triatoma infestans Klug

Benzidine and diamino benzidine (DAB) oxidation, typically performed by peroxidases, was demonstrated by light and electron microscopy in peroxisomes, mitochondria and membranous structures which occurred in close contact with urate crystals in Malpighian tubules of nymphs and adults of Triatoma infestans. Peroxisomes were predominantly identified in cells of the distal region of the tubules, which is engaged in excretory mechanisms. DAB oxidation in mitochondria, even in the absence of hydrogen peroxide, may indicate the existence of a mitochondrial peroxidase and possibly a cytochrome c peroxidase. The localization of the extracellular membranous structures appeared restricted to the lumen of the proximal region of the tubules and they were assumed to be remnants of endoplasmic reticulum containing peroxidases.

Atividade peroxidásica em basófilos de Phrynops geoffroanus (Testudines Chelidae)

As peroxidases, presentes nos peroxissomos e lisossomos, pertencem às oxidases e atuam como catalítico para o peróxido de hidrogênio (H2O2), posteriormente decomposto pela oxidação de cossubstratos, evitando danos celulares.(¹) Foi aplicada a técnica da peroxidase(2) em esfregaços sanguíneos de Phrynops geoffroanus, comparando com sangue humano, para avaliação da atividade e controle da reação. O esfregaço sanguíneo humano apresentou marcações em neutrófilos, fagócitos com muitos lisossomos e peroxissomos (Figura 1). Nos esfregaços sanguíneos de Phrynops geoffroanus, as marcações apresentaram-se nos basófilos (Figura 2), que representam de 10% a 25% dos leucócitos de quelônios e possuem grande número de granulações citoplasmáticas,(3) sugerindo a presença de grande quantidade de enzimas e organelas como lisossomos e peroxissomos, possivelmente associadas a sua participação em reações imunes. A atividade peroxidásica representa resposta do organismo a ações ambientais danosas, servindo como marcador biológico.

Chemical composition and antioxidants potential of extracts of yellow melon seeds in Soybean oil

The aim of this work was to characterize the yellow melon seeds, hybrid variety, as for their proximate composition, and to evaluate the antioxidant potential of extracts of seed in soybean oil. The extract of melon seeds (EM), obtained by extraction using ethanol: water (95:5), was applied in soybean oil at three different concentrations (500; 750 and 1000 mg kg(-1)) and submitted to Shaal oven method at 60 degrees C for 20 days. Oil samples were evaluated for peroxic a value in periods of five days. The antioxidant activity of the extract was compared to the BHT (butyl-hydroxytoluene) activity. The melon seeds showed a high nutrition value, containing high percentages of lipids (25.2%), proteins (20.1%) and fiber (30.0%). All these treatments retarded lipid oxidation in soybean oil; however the natural extracts were less effective than BHT after 10 days in the oven. The antioxidant activities of different treatments tested in this study followed the order: BHT > EM 1000 mg kg(-1) = EM 750 mg kg(-1) > EM 500 mg kg(-1)> control.

Lactic Acid Bacteria Antimicrobial Compounds: Characteristics and Applications

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Characterization of the Pulp and Kernel Oils from Syagrus oleracea, Syagrus romanzoffiana, and Acrocomia aculeata

Vegetable oils are important sources of essential fatty acids. It is, therefore, important to characterize plant species that can be used as new oil sources. This study aimed to characterize the oils from guariroba (Syagrus oleracea), jeriva (Syagrus romanzoffiana), and macauba (Acrocomia aculeata). The physicochemical characterization was performed using official analytical methods for oils and fats, free fatty acids, peroxide value, refractive index, iodine value, saponification number, and unsaponifiable matter. The oxidative stability was determined using the Rancimat at 110 degrees C. The fatty acid composition was performed by gas chromatography. The results were submitted to Tukey's test for the medium to 5% using the ESTAT program. The pulp oils were more unsaturated than kernel oils, as evidenced by the higher refractive index and iodine value, especially the macauba pulp oil which gave 1.4556 and 80 g I(2)/100 g, respectively, for these indices. The kernel oils were less altered by oxidative process and had high induction period, free fatty acids below 0.5%, and peroxide value around 0.19 meq/kg. The guariroba kernel oil showed the largest induction period, 91.82 h.

Alterações físico-químicas dos óleos de girassol, milho e soja em frituras

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

Characterization of native and oxidized starches of two varieties of Peruvian carrot (Arracacia xanthorrhiza, B.) from two production areas of Paraná state, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Características físico-químicas e utilização em alimentos de amidos modificados por tratamento oxidativo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação do óleo de girassol adicionado de antioxidantes sob estocagem

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

Caracterização dos óleos de algumas sementes de frutas como aproveitamento de resíduos industriais

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The Water Effect on the Kinetics of the Bovine Liver Catalase

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)