Comparative effects of fipronil and its metabolites sulfone and desulfinyl on the isolated rat liver mitochondria

Fipronil is an insecticide extensively used to control pests in crops and animals. There are relates of poisoning due to exposure of fipronil in mammals and the liver has been suggested as potential target. In this study, we evaluated the effects of fipronil and its metabolites sulfone and desulfinyl on the bioenergetics, reactive oxygen species (ROS) production and calcium efflux from mitochondria isolated from rat liver. Fipronil (5-25 μM) inhibited state-3 respiration in mitochondria energized with glutamate plus malate, substrates of complex I of the respiratory chain and decreased the mitochondrial membrane potential resulting in inhibition of ATP synthesis. Fipronil also caused uncoupling in succinate-energized mitochondria and calcium efflux. The metabolites sulfone and desulfinyl also acted as mitochondrial inhibitors and uncouplers and caused calcium efflux, but with different potencies, being the sulfone the more potent one. These effects of fipronil and its metabolites on mitochondrial bioenergetics and calcium homeostasis may be related to toxic effects of the insecticide in the liver.

Desenvolvimento de dispersões sólidas e nanopartículas poliméricas mucoadesivas de Zidovudina e avaliação da interação biológica com a mucosa intestinal

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

Estudo dos mecanismos de resistência e virulência de isolados de Cryptococcus neoformans e Cryptococcus gattii e quantificação de genes de bomba de efluxo pós tratamento com Galatos de Alquila

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Identificação e caracterização de metagenomas e isolados bacterianos visando a biorremediação de solos de áreas de mineração

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

Mecanismos de toxicidade dos metabólitos do fipronil, dessulfinil e sulfona, em mitocôndrias isoladas de fígado de rato

Pós-graduação em Ciência e Tecnologia Animal - FEIS

Associação da geoprópolis à quimioterápicos: ação citotóxica e antiproliferativa sobre células HEp-2 e mecanismos envolvidos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização dos compostos derivados de furoxano como inibidores da atividade de bombas de efluxo em Mycobacterium tuberculosis e estudo da influência do efluxo e da halotolerância nos perfis de resistência do bacilo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Production and carbon allocation in monocultures and mixed-species plantations of Eucalyptus grandis and Acacia mangium in Brazil

Introducing nitrogen-fixing tree species in fast-growing eucalypt plantations has the potential to improve soil nitrogen availability compared with eucalypt monocultures. Whether or not the changes in soil nutrient status and stand structure will lead to mixtures that out-yield monocultures depends on the balance between positive interactions and the negative effects of interspecific competition, and on their effect on carbon (C) uptake and partitioning. We used a C budget approach to quantify growth, C uptake and C partitioning in monocultures of Eucalyptus grandis (W. Hill ex Maiden) and Acacia mangium (Willd.) (treatments E100 and A100, respectively), and in a mixture at the same stocking density with the two species at a proportion of 1 : 1 (treatment MS). Allometric relationships established over the whole rotation, and measurements of soil CO2 efflux and aboveground litterfall for ages 4-6 years after planting were used to estimate aboveground net primary production (ANPP), total belowground carbon flux (TBCF) and gross primary production (GPP). We tested the hypotheses that (i) species differences for wood production between E. grandis and A. mangium monocultures were partly explained by different C partitioning strategies, and (ii) the observed lower wood production in the mixture compared with eucalypt monoculture was mostly explained by a lower partitioning aboveground. At the end of the rotation, total aboveground biomass was lowest in A100 (10.5 kg DM m(-2)), intermediate in MS (12.2 kg DM m(-2)) and highest in E100 (13.9 kg DM m(-2)). The results did not support our first hypothesis of contrasting C partitioning strategies between E. grandis and A. mangium monocultures: the 21% lower growth (delta B-w) in A100 compared with E100 was almost entirely explained by a 23% lower GPP, with little or no species difference in ratios such as TBCF/GPP, ANPP/TBCF, delta B-w/ANPP and delta B-w/GPP. In contrast, the 28% lower delta B-w in MS than in E100 was explained both by a 15% lower GPP and by a 15% lower fraction of GPP allocated to wood growth, thus partially supporting our second hypothesis: mixing the two species led to shifts in C allocations from above- to belowground, and from growth to litter production, for both species.

High prevalence of OXA-143 and alteration of outer membrane proteins in carbapenem-resistant Acinetobacter spp. isolates in Brazil

Carbapenem resistance amongst Acinetobacter spp. has been increasing in the last decade. This study evaluated the outer membrane protein (OMP) profile and production of carbapenemases in 50 carbapenem-resistant Acinetobacter spp. isolates from bloodstream infections. Isolates were identified by API20NE. Minimum inhibitory concentrations (MICs) for carbapenems were determined by broth microdilution. Carbapenemases were studied by phenotypic tests, detection of their encoding gene by polymerase chain reaction (PCR) amplification, and imipenem hydrolysis. Nucleotide sequencing confirming the enzyme gene type was performed using MegaBACE 1000. The presence of OMPs was studied by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and PCR. Molecular typing was performed using pulsed-field gel electrophoresis (PFGE). All isolates were resistant to carbapenems. Moreover, 98% of the isolates were positive for the gene encoding the enzyme OXA-51-like, 18% were positive for OXA-23-like (only one isolate did not show the presence of the insertion sequence ISAba1 adjacent to this gene) and 76% were positive for OXA-143 enzyme. Five isolates (10%) showed the presence of the IMP-1 gene. Imipenem hydrolysing activity was detected in only three strains containing carbapenemase genes, comprising two isolates containing the bla(IMP) gene and one containing the bla(OXA-51/OXA-23-like) gene. The OMP of 43 kDa was altered in 17 of 25 strains studied, and this alteration was associated with a high meropenem MIC (256 mu g/mL) in 5 of 7 strains without 43 kDa OMP. On the other hand, decreased OMP 33-36 kDa was found in five strains. The high prevalence of OXA-143 and alteration of OMPs might have been associated with a high level of carbapenem resistance. (C) 2012 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Lipid Transfer to HDL is Higher in Marathon Runners than in Sedentary Subjects, but is Acutely Inhibited During the Run

Although exercise increases HDL-cholesterol, exercise-induced changes in HDL metabolism have been little explored. Lipid transfer to HDL is essential for HDL's role in reverse cholesterol transport. We investigated the effects of acute exhaustive exercise on lipid transfer to HDL. We compared plasma lipid, apolipoprotein and cytokine levels and in vitro transfer of four lipids from a radioactively labeled lipid donor nanoemulsion to HDL in sedentary individuals (n = 28) and in marathon runners (n = 14) at baseline, immediately after and 72 h after a marathon. While HDL-cholesterol concentrations and apo A1 levels were higher in marathon runners, LDL-cholesterol, apo B and triacylglycerol levels were similar in both groups. Transfers of non-esterified cholesterol [6.8 (5.7-7.2) vs. 5.2 (4.5-6), p = 0.001], phospholipids [21.7 (20.4-22.2) vs. 8.2 (7.7-8.9), p = 0.0001] and triacylglycerol [3.7 (3.1-4) vs. 1.3 (0.8-1.7), p = 0.0001] were higher in marathon runners, but esterified-cholesterol transfer was similar. Immediately after the marathon, LDL- and HDL-cholesterol concentrations and apo A1 levels were unchanged, but apo B and triacylglycerol levels increased. Lipid transfer of non-esterified cholesterol [6.8 (5.7-7.2) vs. 5.8 (4.9-6.6), p = 0.0001], phospholipids [21.7 (20.4-22.2) vs. 19.1 (18.6-19.3), p = 0.0001], esterified-cholesterol [3.2 (2.2-3.8) vs. 2.3 (2-2.9), p = 0.02] and triacylglycerol [3.7 (3.1-4) vs. 2.6 (2.1-2.8), p = 0.0001] to HDL were all reduced immediately after the marathon but returned to baseline 72 h later. Running a marathon increased IL-6 and TNF-alpha levels, but after 72 h these values returned to baseline. Lipid transfer, except esterified-cholesterol transfer, was higher in marathon runners than in sedentary individuals, but the marathon itself acutely inhibited lipid transfer. In light of these novel observations, further study is required to clarify how these metabolic changes can influence HDL composition and anti-atherogenic function.

Inhibition of Macrophage Oxidative Stress Prevents the Reduction of ABCA-1 Transporter Induced by Advanced Glycated Albumin

We investigated the role of aminoguanidine and benfotiamine on the inhibition of reactive oxygen species (ROS) generation in macrophages induced by advanced glycated albumin (AGE-albumin) and its relationship with cell cholesterol homeostasis, emphasizing the expression of the ATP binding cassette transporter A-1 (ABCA-1). AGE-albumin was made by incubating fatty acid-free albumin with 10 mM glycolaldehyde. ROS production and ABCA-1 protein level were determined by flow cytometry in J774 macrophages treated along time with control (C) or AGE-albumin alone or in the presence of aminoguanidine or benfotiamine. Mitochondrial function was evaluated by oxygraphy. Compared to C-albumin, AGE-albumin increased ROS production in macrophages, which was ascribed to the activities of NADPH oxidase and of the mitochondrial system. Mitochondrial respiratory chain activity was reduced in cells incubated with AGE-albumin. ROS generation along time was associated with the reduction in macrophage ABCA-1 protein level. Aminoguanidine prevented ROS elevation and restored the ABCA-1 content in macrophages; on the other hand, benfotiamine that promoted a lesser reduction in ROS generation was not able to restore ABCA-1 levels. Inhibition of oxidative stress induced by AGE-albumin prevents disturbances in reverse cholesterol transport by curbing the reduction of ABCA-1 elicited by advanced glycation in macrophages and therefore may contribute to the prevention of atherosclerosis in diabetes mellitus.

Stand-level patterns of carbon fluxes and partitioning in a Eucalyptus grandis plantation across a gradient of productivity, in Sao Paulo State, Brazil

Wood production represents a large but variable fraction of gross primary production (GPP) in highly productive Eucalyptus plantations. Assessing patterns of carbon (C) partitioning (C flux as a fraction of GPP) between above- and belowground components is essential to understand mechanisms driving the C budget of these plantations. Better knowledge of fluxes and partitioning to woody and non-woody tissues in response to site characteristics and resource availability could provide opportunities to increase forest productivity. Our study aimed at investigating how C allocation varied within one apparently homogeneous 90 ha stand of Eucalyptus grandis (W. Hill ex Maiden) in Southeastern Brazil. We assessed annual above-ground net primary production (ANPP: stem, leaf, and branch production) and total belowground C flux (TBCF: the sum of root production and respiration and mycorrhizal production and respiration), GPP (computed as the sum of ANPP, TBCF and estimated aboveground respiration) on 12 plots representing the gradient of productivity found within the stand. The spatial heterogeneity of topography and associated soil attributes across the stand likely explained this fertility gradient. Component fluxes of GPP and C partitioning were found to vary among plots. Stem NPP ranged from 554 g C m(-2) year(-1) on the plot with lowest GPP to 923 g C m(-2) year(-1) on the plot with highest GPP. Total belowground carbon flux ranged from 497 to 1235 g C m(-2) year(-1) and showed no relationship with ANPP or GPP. Carbon partitioning to stem NPP increased from 0.19 to 0.23, showing a positive trend of increase with GPP (R-2 = 0.29, P = 0.07). Variations in stem wood production across the gradient of productivity observed at our experimental site were a result of the variability in C partitioning to different forest system components.

Iodide treatment acutely increases pendrin (SLC26A4) mRNA expression in the rat thyroid and the PCCl3 thyroid cell line by transcriptional mechanisms

Iodine is a critical element involved in thyroid hormone synthesis. Its efflux into the follicular lumen is thought to occur, in part, through pendrin at the apical membrane of thyrocytes. This study attempted to investigate whether iodide administration affects SLC26A4 mRNA expression in rat thyroid and in PCCl3 cells. Rats and cells were treated or not with Nal from 30 min up to 48 h. One group was concomitantly treated with sodium perchlorate. SLC26A4 mRNA expression was also investigated in PCCl3 cells treated with actinomycin D prior to Nal treatment. Iodide administration significantly increased SLC26A4 mRNA content in both models. The simultaneous administration of Nal and perchlorate, as well as the treatment of PCCl3 cells with actinomycin D prevented this effect, indicating that intracellular iodide is essential for this event, which appears to be triggered by transcriptional mechanisms. These data show that intracellular iodide rapidly upregulates SLC26A4 mRNA expression. (C) 2011 Elsevier Ireland Ltd. All rights reserved.

Lipid transfers to HDL are predictors of precocious clinical coronary heart disease

Background: High-density-lipoprotein (HDL) has several antiatherogenic properties and, although the concentration of HDL-cholesterol negatively correlates with incidence of coronary artery disease (CAD), this is not sufficient to evaluate the overall HDL protective role. The aim was to investigate whether precocious CAD patients show abnormalities in lipid transfers to HDL, a fundamental step in HDL metabolism and function. Methods: Thirty normocholesterolemic CAD patients aged <50 y and 30 controls paired for sex, age and B.M.I. were studied. Fasting blood samples were collected for the in vitro lipid transfer assay and plasma lipid determination. A donor nanoemulsion labeled with radioactive free-cholesterol. cholesteryl esters, phospholipids and triglycerides was incubated with whole plasma and after chemical precipitation of non-HDL fractions, supernatant was counted for radioactivity in HDL. Results: LDL and HDL-cholesterol and triglycerides were equal in both groups. Transfers of free-cholesterol (3.8 +/- 1.2%vs 7.0 +/- 33%,p<0.0001) and triglycerides (3.7 +/- 1.7%vs 4.9 +/- 1.9%, p = 0.0125) were diminished in CAD patients whereas cholesteryl ester transfer increased (6.5 +/- 1.9%vs 4.8 +/- 1.8%, p = 0.0008); phospholipid transfer was equal (17.8 +/- 3.5% vs19.5 +/- 3.9%). Conclusion: Alterations in the transfer of lipids to HDL may constitute a new marker for precocious CAD and relation of this metabolic alteration with HDL antiatherogenic function should be investigated in future studies. (C) 2011 Published by Elsevier B.V.

ER stress is associated with reduced ABCA-1 protein levels in macrophages treated with advanced glycated albumin - Reversal by a chemical chaperone

ATP-binding cassette transporter A1 mediates the export of excess cholesterol from macrophages, contributing to the prevention of atherosclerosis. Advanced glycated albumin (AGE-alb) is prevalent in diabetes mellitus and is associated with the development of atherosclerosis. Independently of changes in ABCA-1 mRNA levels, AGE-alb induces oxidative stress and reduces ABCA-1 protein levels, which leads to macrophage lipid accumulation. These metabolic conditions are known to elicit endoplasmic reticulum (ER) stress. We sought to determine if AGE-alb induces ER stress and unfolded protein response (UPR) in macrophages and how disturbances to the ER could affect ABCA-1 content and cholesterol efflux in macrophages. AGE-alb induced a time-dependent increase in ER stress and UPR markers. ABCA-1 content and cellular cholesterol efflux were reduced by 33% and 47%, respectively, in macrophages treated with AGE-alb, and both were restored by treatment with 4-phenyl butyric acid (a chemical chaperone that alleviates ER stress), but not MG132 (a proteasome inhibitor). Tunicamycin, a classical ER stress inductor, also impaired ABCA-1 expression and cholesterol efflux (showing a decrease of 61% and 82%, respectively), confirming the deleterious effect of ER stress in macrophage cholesterol accumulation. Glycoxidation induces macrophage ER stress, which relates to the reduction in ABCA-1 and in reverse cholesterol transport, endorsing the adverse effect of macrophage ER stress in atherosclerosis. Thus, chemical chaperones that alleviate ER stress may represent a useful tool for the prevention and treatment of atherosclerosis in diabetes. (C) 2012 Elsevier Ltd. All rights reserved.