Laboratorio Of Bioquimica

Rio de Janeiro, Brazil

Laboratorio Of Bioquimica

Rio de Janeiro, Brazil
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Diaz A.,National Autonomous University of Mexico | Diaz A.,Laboratorio Experimental Of Enfermedades Neurodegenerativas | Rojas K.,Laboratorio Experimental Of Enfermedades Neurodegenerativas | Espinosa B.,Laboratorio Of Bioquimica | Limon D.,National Autonomous University of Mexico
Neuropeptides | Year: 2014

Alzheimer disease (AD) is a neurodegenerative disorder caused by accumulation of the amyloid-beta peptide (Aβ) in neuritic plaques. Its neurotoxic mechanisms are associated with inflammatory responses and nitrosative stress generation that promote expression of inducible nitric oxide synthase (iNOS) and increased nitric oxide causing neuronal death and memory impairment. Studies suggest that treatment with anti-inflammatory and anti-oxidant agents decreases the risk of developing AD. Aminoguanidine (AG) is an iNOS inhibitor with anti-inflammatory and anti-oxidant effects. In this study, we evaluated the effects of systemic administration of AG (100mg/kg/day for 4days) on spatial memory and inflammatory responses induced by an injection of Aβ25-35 [100μM] into the temporal cortex (TCx) of rats. A significant improvement of spatial memory was evident in the Aβ25-35-treated group at day 30 post-injection subjected to AG treatment; this effect was correlated with decreases in reactive gliosis, IL-1β, TNF-α, and nitrite levels, as well as a reduction in neurodegeneration in the TCx and hippocampus (Hp). These results suggest that AG treatment inhibited glia activation and cytokine release, which may help to counteract neurodegenerative events induced by the toxicity of Aβ. © 2014 Elsevier Ltd.

Diaz P.,University of Seville | Diaz P.,Laboratorio Of Bioquimica | Betti M.,University of Seville | Sanchez D.H.,Max Planck Institute of Molecular Plant Physiology | And 3 more authors.
New Phytologist | Year: 2010

Summary: The role of plastidic glutamine synthetase (GS2) in proline biosynthesis and drought stress responses in Lotus japonicus was investigated using the GS2 mutant, Ljgln2-2. Wild-type (WT) and mutant plants were submitted to different lengths of time of water and nutrient solution deprivation. Several biochemical markers were measured and the transcriptional response to drought was determined by both quantitative real-time polymerase chain reaction and transcriptomics. The Ljgln2-2 mutant exhibited normal sensitivity to mild water deprivation, but physiological, biochemical and massive transcriptional differences were detected in the mutant, which compromised recovery (rehydration) following re-watering after severe drought stress. Proline accumulation during drought was substantially lower in mutant than in WT plants, and significant differences in the pattern of expression of the genes involved in proline metabolism were observed. Transcriptomic analysis revealed that about three times as many genes were regulated in response to drought in Ljgln2-2 plants compared with WT. The transcriptomic and accompanying biochemical data indicate that the Ljgln2-2 mutant is subject to more intense cellular stress than WT during drought. The results presented here implicate plastidic GS2 in proline production during stress and provide interesting insights into the function of proline in response to drought. © The Authors (2010). Journal compilation © New Phytologist Trust (2010).

Cruz-Rus E.,University of Malaga | Amaya I.,Laboratorio Of Bioquimica | Sanchez-Sevilla J.F.,Laboratorio Of Bioquimica | Botella M.A.,University of Malaga | Valpuesta V.,University of Malaga
Journal of Experimental Botany | Year: 2011

Plants have several L-ascorbic acid (AsA) biosynthetic pathways, but the contribution of each one to the synthesis of AsA varyies between different species, organs, and developmental stages. Strawberry (Fragaria×ananassa) fruits are rich in AsA. The pathway that uses D-galacturonate as the initial substrate is functional in ripe fruits, but the contribution of other pathways to AsA biosynthesis has not been studied. The transcription of genes encoding biosynthetic enzymes such as D-galacturonate reductase (FaGalUR) and myo-inositol oxygenase (FaMIOX), and the AsA recycling enzyme monodehydroascorbate reductase (FaMDHAR) were positively correlated with the increase in AsA during fruit ripening. Fruit storage for 72 h in a cold room reduced the AsA content by 30%. Under an ozone atmosphere, this reduction was 15%. Ozone treatment increased the expression of the FaGalUR, FaMIOX, and L-galactose-1-phosphate phosphatase (FaGIPP) genes, and transcription of the L-galactono-1,4-lactone dehydrogenase (FaGLDH) and FAMDHAR genes was higher in the ozone-stored than in the air-stored fruits. Analysis of AsA content in a segregating population from two strawberry cultivars showed high variability, which did not correlate with the transcription of any of the genes studied. Study of GalUR protein in diverse cultivars of strawberry and different Fragaria species showed that a correlation between GalUR and AsA content was apparent in most cases, but it was not general. Three alleles were identified in strawberry, but any sequence effect on the AsA variability was eliminated by analysis of the allele-specific expression. Taken together, these results indicate that FaGalUR shares the control of AsA levels with other enzymes and regulatory elements in strawberry fruit. © 2011 The Author.

Vargas E.A.T.,Laboratorio Of Bioquimica | do Vale Baracho N.C.,Laboratorio Of Bioquimica | de Brito J.,Laboratorio Of Patologia | de Queiroz A.A.A.,Federal University of Itajubá
Acta Biomaterialia | Year: 2010

This study reports on the performance of electrospun hyperbranched polyglycerol nanofibers capable of providing an active agent delivery for wound dressing applications. The aim of this work was to prepare electrospun HPGL nanofibers containing Calendula officinalis as a wound-healing and anti-inflammatory agent. The morphology of the electrospun HPGL-C. officinalis nanofibers was analyzed using a scanning electron microscope. The results showed that the diameters of the fibers were in nanoscales. The release of C. officinalis from the electrospun HPGL fibers was determined by HPLC at a physiological temperature (37 °C). Rapid release of the C. officinalis from the electrospun HPGL-C. officinalis nanofibers was exhibited as result of the high swelling ability as well as the high porosity of the electrospun HPGL-C. officinalis membranes. The degree of swelling, and the mechanical and biocompatible properties of the electrospun HPGL fibers were determined. The results showed that, in physiological conditions, the water absorption into the HPGL electrospun fibers slowed down, governed by the rate at which the electrospun HPGL-C. officinalis membranes interacted with the physiological fluid. The rate of release of C. officinalis seemed to depend on the C. officinalis content in the HPGL nanofibers. From the elastic modulus, it could be seen that elastic electrospun HPGL fibers were obtained with increments of C. officinalis content in the HPGL-C. officinalis membranes. The results of in vivo experiments in rats suggested that HPGL-C. officinalis might be an interesting bioactive wound dressing material for clinical applications. © 2009 Acta Materialia Inc.

Souza J.P.B.L.D.,Centro Universitario Nilton Lins | Nozawa S.R.,Centro Universitario Nilton Lins | Honda R.T.,Centro Universitario Nilton Lins | Honda R.T.,Laboratorio Of Bioquimica
Bulletin of Environmental Contamination and Toxicology | Year: 2012

The objective of this work was to estimate the quantity of mercury residue present in dental amalgam that is generated and discarded in the city of Manaus (Amazon-Brazil). For this purpose, the locations of amalgam usage (10 public and 31 private dental clinics), the method by which the residue is discarded (14 clinics improper disposal), and the analysis of total mercury in the sediment of the controlled landfill (2.68-3 lgHg/g), were described. It was concluded that: there are dental clinics in the city that discard mercury residue into the common waste disposal system, which contravenes health safety standards. © Springer Science+Business Media, LLC 2012.

Neuparth M.J.,University of Porto | Neuparth M.J.,Institute Investigacao e Formacao Avancada em Ciencias e Tecnologias da Saude | Proenca J.B.,Institute Investigacao e Formacao Avancada em Ciencias e Tecnologias da Saude | Santos-Silva A.,Laboratorio Of Bioquimica | And 3 more authors.
Journal of Investigative Medicine | Year: 2014

Background: Physical exercise intervention is known to be crucial in the management of type 2 diabetes mellitus (T2DM). We aimed to evaluate, in patients with T2DM, the effect of regular moderate walking exercise on markers of oxidative stress, lipid metabolism, and inflammation. Methods: We studied 30 patients with T2DM who walked regularly during the last year and 53 patients with T2DM who did not perform any type of exercise. The patients were evaluated for chemerin, adiponectin, leptin, oxidized low-density lipoprotein, and C-reactive protein (CRP) levels. Results: The active T2DM patients showed significantly lower body mass index, as compared with the inactive patients. The active T2DM patients showed significantly lower levels of chemerin and CRP than those of the inactive T2DM patients (CRP lost significance after adjustment for body mass index). The active patients, compared with the inactive, presented a trend toward higher levels of adiponectin and lower values of oxidized low-density lipoprotein. Leptin differed significantly between sexes, and the active women presented a trend toward lower levels as compared with the inactive women. Conclusions: In the patients with T2DM, the practice of moderate walking in a regular basis was sufficient to reduce chemerin levels, which suggests that practice of regular physical exercise should be encouraged. Copyright © 2014 by The American Federation for Medical Research.

Bonnecarrere V.,Instituto Nacional Of Investigacion Agropecuaria Inia | Borsani O.,Laboratorio Of Bioquimica | Diaz P.,Laboratorio Of Bioquimica | Capdevielle F.,Instituto Nacional Of Investigacion Agropecuaria Inia | And 2 more authors.
Plant Science | Year: 2011

Two japonica rice genotypes, INIA Tacuarí and L2825CA, were analyzed for tolerance to low temperature during early vegetative growth. Effect on photosynthesis, energy dissipation, pigment content, xanthophyll-cycle pool conversion, hydrogen peroxide accumulation, oxidative damage and antioxidant enzyme activities were determined to better understand potential mechanisms for cold tolerance. Photoinhibition was measured using chlorophyll fluorescence and oxidative damage by lipid peroxidation and electrolyte leakage. Both genotypes were demonstrated to be cold tolerant which was consistent with their reduced levels of photoinhibition and oxidative damage compared with a cold-sensitive genotype during chilling stress. The strategy for cold tolerance differed between the two genotypes, and involved different mechanisms for disposal of excess energy. The presence of high lutein concentrations and the existence of active non-harmful energy dissipation processes through the xanthophyll cycle appeared to be responsible for chilling tolerance in INIA Tacuarí. On the other hand, increased cold tolerance of L2825CA relative to INIA Tacuarí was related to the higher constitutive superoxide dismutase (SOD, EC, ascorbate peroxidase (APX, EC and catalase (CAT, EC © 2011 Elsevier Ireland Ltd.

Azziz G.,Laboratorio Of Microbiologia | Trasante T.,Laboratorio Of Microbiologia | Monza J.,Laboratorio Of Bioquimica | Irisarri P.,Laboratorio Of Microbiologia
Applied Soil Ecology | Year: 2016

Ammonia-oxidizing microorganisms are partly responsible for the production of N2O, a potent greenhouse gas. Rice paddies provide a habitat where ammonia oxidizing microorganisms can be active. The influence of different agricultural practices on these microorganisms, particularly on archaeal ammonia oxidizers, is an active field of research. In this work, we conducted two greenhouse experiments where we analyzed the influence of two soil types with different organic matter contents, two rice cultivars and water management on both archaeal (AOA) and bacterial (AOB) ammonia oxidizers. We determined the AOA and AOB abundance and population structure by q-PCR and T-RFLP, respectively. The archaeal and bacterial ammonia monooxygenase subunit A gene was used as the PCR target. The AOA and AOB copy numbers were affected by sampling time in both experiments. AOA abundance was also influenced by the time of flooding. The population structure of AOA was more variable than that of AOB and was strongly determined by soil type. Changes in AOB population structure were observed mainly according to sampling time. © 2015 Elsevier B.V..

PubMed | Laboratorio Of Biologia Celular Y Productos Naturales, National Autonomous University of Mexico, National Polytechnic Institute of Mexico and Laboratorio Of Bioquimica
Type: Journal Article | Journal: Biochimica et biophysica acta | Year: 2016

Platelets are small, anucleated cell fragments that activate in response to a wide variety of stimuli, triggering a complex series of intracellular pathways leading to a hemostatic thrombus formation at vascular injury sites. However, in essential hypertension, platelet activation contributes to causing myocardial infarction and ischemic stroke. Reported abnormalities in platelet functions, such as platelet hyperactivity and hyperaggregability to several agonists, contribute to the pathogenesis and complications of thrombotic events associated with hypertension. Platelet membrane lipid composition and fluidity are determining for protein site accessibility, structural arrangement of platelet surface, and response to appropriate stimuli. The present study aimed to demonstrate whether structural and biochemical abnormalities in lipid membrane composition and fluidity characteristic of platelets from hypertensive patients influence the expression of the Epithelial Sodium Channel (ENaC), fundamental for sodium influx during collagen activation. Wb, cytometry and quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR) assays demonstrated ENaC overexpression in platelets from hypertensive subjects and in relation to control subjects. Additionally, our results strongly suggest a key role of -dystroglycan as a scaffold for the organization of ENaC and associated proteins. Understanding of the mechanisms of platelet alterations in hypertension should provide valuable information for the pathophysiology of hypertension.

PubMed | Institute Investigaciones Biologicas Clemente Estable, Laboratorio Of Microbiologia and Laboratorio Of Bioquimica
Type: | Journal: Plant physiology and biochemistry : PPB | Year: 2016

Cyanobacteria are successful in diverse habitats due to their adaptation strategies. Their mechanisms to cope with individual stresses have been studied. However, the response to combined stress conditions as found in nature remains unclear. With this aim, we studied the dual effect of 24h-osmotic and 3h-UV irradiation on the cyanobacterium Calothrix BI22. Our approach included the study of redox homeostasis, oxidative damage, reactive oxygen species production-consumption processes and photosynthetic activity. Superoxide invivo determination with confocal image processing showed the highest accumulation under UV. However, no lipoperoxidation occurred due to a high SOD activity. This cyanobacterium was less prepared to cope with the osmotic stress assayed. Under this condition, O

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