Mechanism of Trypanosoma cruzi death induced by Cratylia mollis seed lectin

Incubation of T. cruzi epimastigotes with the lectin Cramoll 1,4 in Ca(2+) containing medium led to agglutination and inhibition of cell proliferation. The lectin (50 A mu g/ml) induced plasma membrane permeabilization followed by Ca(2+) influx and mitochondrial Ca(2+) accumulation, a result that resembles the classical effect of digitonin. Cramoll 1,4 stimulated (five-fold) mitochondrial reactive oxygen species (ROS) production, significantly decreased the electrical mitochondrial membrane potential (Delta I(m)) and impaired ADP phosphorylation. The rate of uncoupled respiration in epimastigotes was not affected by Cramoll 1,4 plus Ca(2+) treatment, but oligomycin-induced resting respiration was 65% higher in treated cells than in controls. Experiments using T. cruzi mitochondrial fractions showed that, in contrast to digitonin, the lectin significantly decreased Delta I(m) by a mechanism sensitive to EGTA. In agreement with the results showing plasma membrane permeabilization and impairment of oxidative phosphorylation by the lectin, fluorescence microscopy experiments using propidium iodide revealed that Cramoll 1,4 induced epimastigotes death by necrosis.

EVALUATION OF METAL TOXICITY BY A MODIFIED METHOD BASED ON THE FUNGUS GERRONEMA VIRIDILUCENS BIOLUMINESCENCE IN AGAR MEDIUM

Metal cation toxicity to basidiomycete fungi is poorly understood, despite its well-known importance in terrestrial ecosystems. Moreover, there is no reported methodology for the routine evaluation of metal toxicity to basidiomycetes. In the present study, we describe the development of a procedure to assess the acute toxicity of metal cations (Na(+), K(+), Li(+), Ca(2+), Mg(2+), Co(2+), Zn(2+), Ni(2+), Mn(2+), Cd(2+), and Cu(2+)) to the bioluminescent basidiomycete fungus Gerronema viridilucens. The method is based on the decrease in the intensity of bioluminescence resulting from injuries sustained by the fungus mycelium exposed to either essential or nonessential metal toxicants. The assay described herein enables LIS to propose a metal toxicity series to Gerronenia viridilucens based on data obtained from the bioluminescence intensity (median effective concentration [EC50] values) versus metal concentration: Cd(2+) > Cu(2+) > Mn(2+) approximate to Ni(2+) approximate to Co(2+) > Zn(2+) > Mg(2+) > Li(+) > K(+) approximate to Na(+) > Ca(2+), and to shed some li-ht on the mechanism of toxic action of metal cations to basidiomycete fungi. Environ. Toxicol. Chem. 2010;29:320-326. (C) 2009 SETAC

A compact and high-resolution version of a capacitively coupled contactless conductivity detector

An all-in-one version of a capacitively coupled contactless conductivity detector is introduced. The absence of moving parts (potentiometers and connectors) makes it compact (6.5 cm(3)) and robust. A local oscillator, working at 1.1 MHz, was optimized to use capillaries of id from 20 to 100 lam. Low noise circuitry and a high-resolution analog-to-digital converter (ADC) (21 bits effective) grant good sensitivities for capillaries and background electrolytes currently used in capillary electrophoresis. The fixed frequency and amplitude of the signal generator is a drawback that is compensated by the steady calibration curves for conductivity. Another advantage is the possibility of determining the inner diameter of a capillary by reading the ADC when air and subsequently water flow through the capillary. The difference of ADC reading may be converted into the inner diameter by a calibration curve. This feature is granted by the 21-bit ADC, which eliminates the necessity of baseline compensation by hardware. In a typical application, the limits of detection based on the 3 sigma criterion (without baseline filtering) were 0.6, 0.4, 0.3, 0.5, 0.6, and 0.8 mu mol/L for K(+), Ba(2+), Ca(2+), Na(+), Mg(2+), and Li(+), respectively, which is comparable to other high-quality implementations of a capacitively coupled contactless conductivity detector.

Removal of metal ions from aqueous solution by chelating polymeric hydrogel

Polysaccharide natural seed coat from the tree Magonia pubescens, in the form of hydrogel was used to remove metals in aqueous solution. Swelling tests indicate that seed coat presents hydrogel behavior, with maximum water absorption of 292 g water/g. Adsorption experiments performed using Na(+), Mg(2+), K(+), Ca(2+), Cr(3+), Fe(3+) and Zn(2+) demonstrated that the polysaccharide structure has a high capacity to extract these ions from the aqueous solution. Scanning electron microscopy revealed significant morphological changes of the material before and after water contact. Differential scanning calorimetry measurements indicate a signal shift of the water evaporation temperature in the material with adsorbed zinc. X-ray photoelectron spectroscopy analysis combined with theoretical studies by the density functional theory and on Hartree-Fock (HF) level evidence that the metallic ions were adsorbed through coordination with hydroxyl groups of polysaccharide. In the case of Zn(2+) the lowest HF energy was observed for the tetracoordination mode, where Zn(2+) is coordinated by two hydroxyl groups and two water molecules.

Development of a fast capillary electrophoresis method to determine inorganic cations in biodiesel samples

The aim of this study was to develop a fast capillary electrophoresis method for the determination of inorganic cations (Na(+), K(+), Ca(2+), Mg(2+)) in biodiesel samples, using barium (Ba(2+)) as the internal standard. The running electrolyte was optimized through effective mobility curves in order to select the co-ion and Peakmaster software was used to determine electromigration dispersion and buffer capacity. The optimum background electrolyte was composed of 10 mmol L(-1) imidazole and 40 mmol L(-1) of acetic acid. Separation was conducted in a fused-silica capillary (32 cm total length and 23.5 cm effective length, 50 mu m I.D.), with indirect UV detection at 214 nm. The migration time was only 36 s. In order to obtain the optimized conditions for extraction, a fractional factorial experimental design was used. The variables investigated were biodiesel mass, pH, extractant volume, agitation and sonication time. The optimum conditions were: biodiesel mass of 200 mg, extractant volume of 200 mu L. and agitation of 20 min. The method is characterized by good linearity in the concentration range of 0.5-20 mg kg(-1) (r > 0.999), limit of detection was equal to 0.3 mg kg(-1), inter-day precision was equal to 1.88% and recovery in the range of 88.0-120%. The developed method was successfully applied to the determination of cations in biodiesel samples. (c) 2010 Elsevier B.V. All rights reserved.

Surface-Enhanced Resonance Raman Scattering of Polyaniline on Silver and Gold Colloids

The interaction of emeraldine base (PANI-EB) with silver and gold colloids was probed by using Surface-Enhanced Resonance Raman Scattering (SERRS) at 3 different exciting radiations. Due to the great sensitivity of SERRS technique the detection limit of PANI-EB concentration was ca. 2 x 10(-7) mol L(-1) in Ag and Au colloidal suspensions. The UV-vis-NIR spectra of metal colloids in function of PANI-EB concentrations showed that gold colloids present a higher degree of aggregation than silver colloids. SERRS of PANI-EB on metal colloids allowed the study of the polymeric species formed primarily on the metallic surface. The polymer formed after the adsorption of PANI-EB on metallic nanoparticles is strongly dependent on the nature of the metal colloids. The oxidation of PANI-EB to pernigraniline occurred for silver colloids, while a doping process of PANI-EB on Au nanoparticles was evidenced through the observation of the characteristic SERRS spectrum of emeraldine salt at 1064nm.

F��rstude: Beskrivning av uppv��rmningssystem med solf��ngare och v��rmepump f��r omr��det Anneberg i Danderyds Kommun

Anneberg är ett område i Danderyds kommun där det skall beredas plats för ett nytt bostadsområde. Området skall bebyggas med flerbostadshus, gruppbostäder och ett sjukhem. Denna förstudie beskriver översiktligt 3 systemförslag som kan användas för uppvärmning av husen i bostadsområdet Anneberg. Målsättningen är att presentera uppvärmningssystem som visar hur solenergi kan användas för att öka värmepumpsystemens värmefaktor.Systemen modellerades i TRNSYS och systemfunktionen samt energiflöden simulerades. Simulerade prestanda för tre olika typer av uppvärmningssystem redovisas. System A är ett vanligt värmepumpsystem med borrhål och värmepump placerad i ett flerfamiljshus av typ 3. System B liknar system A, men har kompletterats med en glasad solfångare för varmvattenberedning. System C är en lösning som kan tillämpas för större byggnader eller för ett område med flera byggnader. Systemet har ett gemensamt värmelager och ett kulvertsystem som förbinder byggnaderna med värmelagret. I varje ansluten byggnad installeras sedan en värmepump och en oglasad solfångare.Simuleringsresultatet redovisas som en värmefaktor för systemets fem första driftår. System A får en värmefaktor på mellan 2,3 och 2,7 för de första 5 driftåren. System B får en värmefaktor på mellan 3,4 och 3,7 och system C får en värmefaktor på mellan 4,0 och 4,5. Studien visar att det går att öka värmefaktorn på en värmepumpanläggning från ca 2,5 upp till 4 eller 4,5 genom att komplettera anläggningen med solfångare och värmelager. Detta innebär att elförbrukningen minskar från att vara ca 40 % av värmebehovet ned till under 25 % av värmebehovet. Det bör således finnas en potential för att komplettera värmepumpanläggningar med solvärme. Vilket utförande som kan bli ekonomiskt intressant kan inte bedömas i denna förstudie. I förstudien visas enbart resultatet för tre enstaka systemutföranden. Inga parametervariationer (tex solfångaryta, antal borrhål och avstånd mellan borrhålen) är utförda. En sådan systemoptimering bör göras med förstudien som utgångsläge.

Efeito do glutamato sobre a secre����o da prote��na S100B em cultura de astr��citos hipocampais

A prote��na S100B pertence �� fam��lia S100 de prote��nas ligantes de Ca+2. Sua express��o d��-se primariamente em astr��citos, os quais tamb��m secretam esta prote��na, exercendo um papel tr��fico sobre as c��lulas vizinhas. A adi����o de S100B tem promovido a sobreviv��ncia de neur��nios em cultura e, recentemente, tem sido proposto um papel protetor da S100B contra a excitoxicidade. Neste trabalho investigamos a libera����o de S100B na presen��a de alta concentra����o de glutamato. A secre����o de S100B em astr��citos de ratos em cultura foi quantificada, pelo m��todo de ELISA, durante 24 horas ap��s uma priva����o de soro de 30 minutos (condi����o estimulada) ou n��o (condi����o basal). A integridade dos astr��citos foi analisada por ensaios de exclus��o de azul de tripan e medida da LDH. Glutamato (1 mM) n��o teve efeito sobre a secre����o basal de S100B, mas diminuiu a libera����o 1h depois da priva����o de soro. A priva����o de soro que estimulou a libera����o de S100B foi dependente de s��ntese prot��ica e reduzida por Rp-AMPc e H-89, sugerindo o envolvimento da via AMPc/PKA, possivelmente sobre o elemento sens��vel ao AMPc no gene de S100B. Al��m disso, a priva����o de soro foi acompanhada por um aumento transit��rio do conte��do intracelular de AMPc. Nossos resultados sugerem que o proposto papel neurotr��fico da S100B, pelo menos em cultura de astr��citos hipocampais, poderia estar prejudicado por altos n��veis de glutamato. N��o est�� claro ainda se o efeito do glutamato �� medeado por receptores. Na tentativa de investigar o mecanismo envolvido usamos inibidores do transporte de glutamato e agonistas de glutamato. Os resultados indicam que ambos receptores metabotr��picos do Grupo I/II e transportadores de glutamato est��o envolvidos no decr��scimo da secre����o de S100B induzida pelo glutamato.

Geologia e recursos h��dricos subterr��neos da Ilha da Madeira

Nesta tese da especialidade de Hidrogeologia, �� apresentado um primeiro levantamento vulcano-estratigr��fico da ilha da Madeira. Os trabalhos de campo permitiram definir, at�� agora, sete unidades geol��gicas principais, descritas da mais antiga para a mais recente: 1- Complexo Vulc��nico Antigo (CA) 2- Calc��rios Marinhos dos Lameiros - S. Vicente (CM) 3- Dep��sito Conglomer��tico-Brech��ide (CB) 4- Complexo Vulc��nico Principal (CP) 5- Complexo Vulc��nico S. Roque/Paul (SRP) 6- Epis��dios Vulc��nicos Recentes (VR) 7- Dep��sitos de Vertente (dv), Faj��s (fj), Quebradas (q), Dep��sitos de Enxurrada Recentes (dr), Areias de Praia (ap), Dunas F��sseis (df), Terra��os (t), e Aluvi��es (a) A caracteriza����o clim��tica da ilha da Madeira foi feita com base nos dados recolhidos em 27 pontos de observa����o climatol��gicos, dos quais 14 s��o esta����es meteorol��gicas e 13 s��o postos udom��tricos, o que representa uma densidade de 1 ponto de observa����o/27 km2. Constatou-se que a varia����o da precipita����o com a altitude n��o era linear e dependia da orienta����o das vertentes. Efectuou-se o balan��o h��drico sequencial di��rio, com base nos valores de precipita����o m��dia di��ria, registados no Paul da Serra, durante os ��ltimos 15 anos hidrol��gicos. Pretendeu-se quantificar a precipita����o oculta na vegeta����o t��pica da ilha da Madeira, de modo a poder avaliar a contribui����o daquele tipo de precipita����o para os recursos h��dricos subterr��neos, e, ainda, determinar qual o potencial daquele recurso natural, como contribui����o importante ��s fontes tradicionais de abastecimento de ��gua �� ilha. Para o efeito, procedemos a dois tipos principais de medi����o: medi����o directamente sob a vegeta����o de altitude da Madeira, o urzal, que se desenvolve entre os 1200 e os 1600 m de altitude, e constru����o de aparelhos constitu��dos por obst��culos artificiais, de modo a interceptarem as got��culas de ��gua contidas no nevoeiro. Pela sua import��ncia, os resultados obtidos justificam o desenvolvimento futuro deste estudo. A caracteriza����o hidrodin��mica das forma����es da ilha da Madeira baseou-se nas observa����es feitas no interior das galerias e t��neis em escava����o, na an��lise dos registos de caudais de galerias e nascentes e na interpreta����o de ensaios de bombeamento dos furos de capta����o. Os dados evidenciam a grande heterogeneidade e anisotropia caracter��sticas do meio vulc��nico. As transmissividades v��o desde 11 m2/d at�� 25 766 m2/d. A caracteriza����o hidrogeoqu��mica permitiu identificar um grupo de 5 ��guas termais, emergentes em falhas, no Complexo Antigo, com caracter��sticas muito pr��prias, bastante distintas das restantes, que representam, quer em quantidade, quer em volume de caudais captados, a grande maioria das ��guas da ilha da Madeira. O principal fen��meno mineralizador das ��guas �� a hidr��lise de minerais silicatados, verificando-se, nas ��guas dos furos, nas das nascentes de altitude e nas situadas pr��ximo do litoral, o efeito da contamina����o de sais de origem marinha. A partir dos dados hidrogeol��gicos obtidos, foi poss��vel elaborar um modelo conceptual de funcionamento hidrogeol��gico para a ilha da Madeira, que, apesar de possuir alguns elementos comuns, ��, no seu conjunto, diferente dos modelos conhecidos para outras ilhas vulc��nicas, nomeadamente, Can��rias, Reuni��o, Havai e Polin��sia Francesa.

Purifica����o, caracteriza����o e efeitos imunomodulat��rio e antiproliferativo de uma lectina do fungo Clavaria cristata (Holmsk.) Pers

A 140,0 kDa lectin was purified and characterized from the mushroom Clavaria cristata. The purification procedures from the crude extract of the mushroom comprised gel filtration chromatography on Sephacryl s200 and ion exchange on Resource Q column. The purified lectin agglutinated all types of human erythrocytes with preference for trypsinized type O erythrocytes. The haemagglutinating activity is dependent of Ca 2+ ions and was strongly inhibited by the glycoprotein bovine submaxillary mucin (BSM) up to the concentration of 0, 125 mg/mL. The C. cristata lectin (CcL) was stable in the pH range of 2,5-11,5 and termostable up to 80 ��C. CcL molecular mass determined by gel filtration on a Superose 6 10 300 column was approximately 140,3 kDa. SDS polyacrilamide gel electrophoresis revealed a single band with a molecular mass of approximately 14,5 kDa, when the lectin was heated at 100 ���C in the presence or absence of ��-mercaptoethanol. CcL induced activation of murine peritoneal macrophages in vitro resulting in the release of nitric oxide (NO), reaching the maximum production at 24 h. In experimental paw oedema model in mice, CcL showed proinflammatory activity being able to induce oedema formation. Cell viability of HepG2, MDA 435 e 3T3 cell lines was examined after 72 h of incubation with CcL in different concentrations (0,5-50 ��g/mL). CcL inhibited HepG2 cells growth with an IC50 value of 50 ��g/mL. In the present work, the observed immunomodulatory and antiproliferative effects indicate CcL as a possible immunomodulator compound, interfering in the macrophages immune response, taking possible anti-parasitic, anti-tumoral effects or diagnostic and/or therapeutic

Estudos de Durabilidade Frente ao Ataque ��cido de Comp��sitos Portland-Pol��mero para Cimenta����o de Po��os de Petr��leo

Portland-polymers composites are promising candidates to be used as cementing material in Northeastern oil wells of Brazil containing heavy oils submitted to steam injection. In this way, it is necessary to evaluate its degradation in the commonly acidizind agents. In addition, to identify how aggressive are the different hostile environments it is an important contribution on the decision of the acidic systems to be used in. It was investigated the performance of the Portland-polymer composites using powdered polyurethane, aqueous polyurethane, rubber tire residues and a biopolymer, those were reinforced with polished carbon steel SAE 1045 to make the electrochemical measurements. HCl 15,0 %, HCl 6,0 % + HF 1,5 % (soft mud acid), HCl 12,0 % + HF 3,0 % (regular mud acid) and HAc 10 % + HF 1,5 % were used as degrading environment and electrolytes. The more aggressive acid solution to the plain Portland hardened cement paste was the regular mud acid, that showed loss of weight around 23.0 %, followed by the soft mud acid, the showed 11.0 %, 15.0 % HCl with 7,0 % and, at last the 10.0 % HAc plus HF 1.5 % with just 1.0 %. The powdered polyurethane-composite and the aqueous polyurethane one showed larger durability, with reduction around 87.0 % on the loss of weight in regular mud acid. The acid attack is superficial and it occurs as an action layer, where the degraded layer is responsible for the decrease on the kinetic of the degrading process. This behavior can be seen mainly on the Portland- aqueous polyurethane composite, because the degraded layer is impregnated with chemically modified polymer. The fact of the acid attack does not have influence on the compressive strength or fratography of the samples, in a general way, confirms that theory. The mechanism of the efficiency of the Portland-polymers composites subjected to acid attack is due to decreased porosity and permeability related with the plain Portland paste, minor quantity of Ca+2, element preferentially leached to the acidic solution, wave effect and to substitute part of the degrading bulk for the polymeric one. The electrolyte HAc 10 % + HF 1,5 % was the least aggressive one to the external corrosion of the casing, showing open circuit potentials around +250 mV compared to -130 mV to the simulated pore solution to the first 24 hours immersion. This behavior has been performed for two months at least. Similar corrosion rates were showed between both of the electrolytes, around 0.01 μA.cm-2. Total impedance values, insipient arcs and big polarization resistance capacitive arcs on the Nyquist plots, indicating passivity process, confirm its efficiency. In this way, Portlandpolymers composites are possible solutions to be succeed applied to oilwell cementing concomitant submitted to steam injection and acidizing operation and the HAc 10,0 % + HF 1,5 % is the less aggressive solution to the external corrosion of the casing

Enzymatic and structural characterization of new PLA2 isoform isolated from white venom of Crotalus durissus ruruima

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)

Biochemical and functional properties of a thrombin-like enzyme isolated from Bothrops pauloensis snake venom

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)

The locus coeruleus and central chemosensitivity

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)

Efeito do manejo da entrelinha da seringueira sobre as propriedades qu��micas do solo, o estado nutricional e o crescimento

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)