Evaluation in white mice of the infectivity of egs of Lagochilascaris minor (Nematoda: ascarididae), incubated by decortication with sodium hypochlorite (NaOCl)

White mice were used to study the infectivity of the eggs of Lagochilascaris minor Leiper, 1909 after incubation in liquid media, with or without preservative substances. Potassium bichromate (K2Cr2O7) at 1% restrict hatching, while 1% formalin gave a greater larval yield. Incubation of eggs in distilled water, in Roux or Falcon flasks gave a good yield, whether the eggs were obtained from human feces or from experimentally infected cats. Treatment of eggs with Sodium hypochlorite (NaOCl) at 5.25% for 2 min prior to inoculation, produced a notable increment of the larval yield in the infections.

Comparative study on the localization of adult Schistosoma mansoni worms in albino mice anesthetized with pentobarbital sodium, ether or chlorophorm

The effect of anesthetic drugs on the localization of adult worms in albino mice was compared. The animals with 56 days of infection were anesthetized with pentobarbital sodium, ether or chlorophorm. Perfusion was carried out immediately after, recovering the worms and classifying them in relation to their localization on the liver or portal vein and the mesenteric veins. Our results showed that pentobarbital sodium produced a greater displacement of the worms to the liver (89%) than ether (76%) and chlorophorm (34%) did, when compared to the control group (22%). The difference between pentobarbital sodium and ether was significant (p < 0.05). We suggest that anesthetic drugs may not be used in studies on the distribution of adult worms in several hosts.

Desenvolvimento e aplicação de um biossensor para monitorização de creatinina, um biomarcador associado a doenças emergentes

Este trabalho descreve o desenvolvimento de um material sensor para creatinina por impressão molecular em estrutura polimérica (MIP) e a sua aplicação no desenvolvimento de um dispositivo de natureza potenciométrica para a determinação da molécula alvo em fluidos biológicos. A creatinina é um dos biomarcadores mais utilizados no acompanhamento da doença renal, já que é um bom indicador da taxa de filtração glomerular (TFG). Os materiais biomiméticos desenhados para interação com a creatinina foram obtidos por polimerização radicalar, recorrendo a monómeros de ácido metacríclico ou de vinilpiridina e a um agente de reticulação apropriado. De modo a aferir o efeito da impressão da creatinina na resposta dos materiais MIP à sua presença, foram também preparados e avaliados materiais de controlo, obtidos sem impressão molecular (NIP). O controlo da constituição química destes materiais, incluindo a extração da molécula impressa, foi realizado por Espectroscopia de Raman e de Infravermelho com Transformada de Fourrier. A afinidade de ligação entre estes materiais e a creatinina foi também avaliada com base em estudos cinéticos. Todos os materiais descritos foram integrados em membranas selectivas de elétrodos seletivos de ião, preparadas sem ou com aditivo iónico lipófilo, de carga negativa ou positiva. A avaliação das características gerais de funcionamento destes elétrodos, em meios de composição e pH diferentes, indicaram que as membranas com materiais impressos e aditivo aniónico eram as únicas com utilidade analítica. Os melhores resultados foram obtidos em solução tampão Piperazine-N,N′-bis(2- ethanesulfonic acid), PIPES, de pH 2,8, condição que permitiu obter uma resposta quasi-Nernstiana, a partir de 1,6×10-5 mol L-1. Estes elétrodos demonstraram ainda uma boa selectividade ao apresentaram uma resposta preferencial para a creatinina quando na presença de ureia, carnitina, glucose, ácido ascórbico, albumina, cloreto de cálcio, cloreto de potássio, cloreto de sódio e sulfato de magnésio. Os elétrodos foram ainda aplicados com sucesso na análise de amostras sintéticas de urina, quando os materiais sensores eram baseados em ácido metacrilico, e soro, quando os materiais sensores utilizados eram baseados em vinilpiridina.

Characterization of molybdenum and tungsten formate dehydrogenases from sulfate reducing bacteria

Dissertação apresentada para a obtenção do Grau de Doutor em Bioquímica, especialidade Bioquímica-Física pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia

New molecularly-imprinted polymer for carnitine and its application as ionophore in potentiometric selective membranes

Carnitine (CRT) is a biological metabolite found in urine that contributes in assessingseveral disease conditions, including cancer. Novel quick screening procedures for CRT are therefore fundamental. This work proposes a novel potentiometric device where molecularly imprinted polymers (MIPs) were used as ionophores. The host-tailored sites were imprinted on a polymeric network assembled by radical polymerization of methacrylic acid (MAA) and trimethylpropane trimethacrylate (TRIM). Non-imprinted polymers (NIPs) were produced as control by removing the template from the reaction media. The selective membrane was prepared by dispersing MIP or NIP particles in plasticizer and poly(vinyl chloride), PVC, and casting this mixture over a solid contact support made of graphite. The composition of the selective membrane was investigated with regard to kind/amount of sensory material (MIP or NIP), and the need for a lipophilic additive. Overall, MIP sensors with additive exhibited the best performance, with near-Nernstian response down to ~ 1 × 10− 4 mol L− 1, at pH 5, and a detection limitof ~ 8 × 10− 5 mol L− 1. Suitable selectivity was found for all membranes, assessed by the matched potential method against some of the most common species in urine (urea, sodium, creatinine, sulfate, fructose and hemoglobin). CRT selective membranes including MIP materials were applied successfully to the potentiometric determination of CRT in urine samples.

Formate metabolism in sulfate reducing bacteria

Dissertation presented to obtain the Ph.D degree in Biochemistry

Cobalt-, zinc- and iron-bound forms of adenylate kinase (AK) from the sulfate-reducing bacterium Desulfovibrio gigas: purification, crystallization and preliminary X-ray diffraction analysis

Acta Crystallogr Sect F Struct Biol Cryst Commun. 2009 Sep 1;65(Pt 9):926-9

Purification, crystallization and preliminary X-ray diffraction analysis of adenosine triphosphate sulfurylase (ATPS) from the sulfate-reducing bacterium Desulfovibrio desulfuricans ATCC 27774

Acta Crystallogr Sect F Struct Biol Cryst Commun. 2008 Jul 1;64(Pt 7):593-5

Purification and Preliminary Characterization of Tetraheme Cytochrome and Adenylylsulf te Reductase from the Peptidolytic Sulfate-Reducing Bacterium Desulfovibrio aminophilus DSM 12254

Bioinorganic Chemistry and Applications Volume 3 (2005), Issue 1-2, Pages 81-91

Neurotoxic activity and ultrastructural changes in muscles caused by the brown widow spider Latrodectus geometricus venom

Brown widow spider (Latrodectus geometricus) venom (BrWSV) produces few local lesions and intense systemic reactions such as cramps, harsh muscle pains, nausea, vomiting and hypertension. Approximately 16 protein bands under reducing conditions and ~ 14 bands under non-reducing conditions on a 12.5% sodium dodecyl sulfate-polyacrylamide gel electrophoresis were observed. Neurotoxic clinical manifestations were confirmed in vivo, while proteolytic activity was demonstrated on gelatine film. Severe ultrastructural damages in mice skeletal muscles were observed at 3, 6, 12 and 24 h postinjection with at total of 45 µg of venom protein. Infiltration of eosinophils and ruptures of the cellular membranes were observed in the muscles along with swelling of the nuclear cover and interruption of the collagen periodicity. Altered mitochondrias and autophage vacuoles, nuclear indentation and mitochondria without cristae, slight increment of intermyofibrillar and subsarcolemic spaces and myelinic figures formation were also observed. In the capillary, endothelial membrane unfolding into the lumen was noticed; along with myelinic figures compatible with a toxic myopathy. Swollen sarcotubular systems with lysis of membrane, intense mitochondria autophagia and areas without pinocytic vesicles were observed. Swollen mitochondria surrounded by necrotic areas, myofibrillar disorganization and big vacuolas of the sarcotubular system, degenerated mitochondrium with formation of myelinic figure was seen. Glycogenosomes with small particulate, muscle type glycogen was noticed. Autophagic vacuole (autophagolysosomes) and necrotic areas were also noticed. These damages may be due to interactive effects of the multifactorial action of venom components. However, Latrodectus geometricus venom molecules may also be utilized as neuro therapeutic tools, as they affect neuronal activities with high affinity and selectivity. To our knowledge, the present study is the first ultrastructural report in the literature of muscle injuries and neurological and proteolytic activities caused by BrWSV.

Construção de um sensor eletroquímico molecularmente impresso para monitorização do cancro da mama

O Cancro da mama é uma doença cuja incidência tem vindo a aumentar de ano para ano e além disso é responsável por um grande número de mortes em todo mundo. De modo a combater esta doença têm sido propostos e utilizados biomarcadores tumorais que permitem o diagnóstico precoce, o acompanhamento do tratamento e/ou a orientação do tipo tratamento a adotar. Atualmente, os biomarcadores circulantes no sangue periférico recomendados pela Associação Americana de Oncologia Clinica (ASCO) para monitorizar os pacientes durante o tratamento são o cancer antigen 15-3 (CA 15-3), o cancer antigen 27.29 (CA 27.29) e o cancer embryobic antigen (CEA). Neste trabalho foi desenvolvido um sensor eletroquímico (voltamétrico) para monitorizar o cancro da mama através da análise do biomarcador CA 15-3. Inicialmente realizou-se o estudo da adsorção da proteína na superfície do elétrodo para compreender o comportamento do sensor para diferentes concentrações. De seguida, estudaram-se três polímeros (poliaminofenol, polifenol e polifenilenodiamina) e selecionou-se o poliaminofenol como o polímero a utilizar, pois possuía a melhor percentagem de alteração de sinal. Após a seleção do polímero, este foi depositado na superfície do elétrodo por eletropolimerização, formando um filme polimérico molecularmente impresso (MIP) à volta da proteína (molde). Posteriormente, foram analisados cinco solventes (água, mistura de dodecil sulfato de sódio e ácido acético, ácido oxálico, guanidina e proteinase K) e o ácido oxálico revelou ser mais eficaz na extração da proteína. Por último, procedeu-se à caraterização do sensor e analisou-se a resposta analítica para diferentes concentrações de CA 15-3 revelando diferenças claras entre o NIP (polímero não impresso) e o MIP.

ANTIFUNGAL ACTIVITY OF SILVER NANOPARTICLES OBTAINED BY GREEN SYNTHESIS

Silver nanoparticles (AgNPs) are metal structures at the nanoscale. AgNPs have exhibited antimicrobial activities against fungi and bacteria; however synthesis of AgNPs can generate toxic waste during the reaction process. Accordingly, new routes using non-toxic compounds have been researched. The proposal of the present study was to synthesize AgNPs using ribose as a reducing agent and sodium dodecyl sulfate (SDS) as a stabilizer. The antifungal activity of these particles against C. albicans and C. tropicalis was also evaluated. Stable nanoparticles 12.5 ± 4.9 nm (mean ± SD) in size were obtained, which showed high activity against Candida spp. and could represent an alternative for fungal infection treatment.

Structural and electron paramagnetic resonance (EPR) studies of mononuclear molybdenum enzymes from sulfate-reducing bacteria

Acc. Chem. Res., 2006, 39 (10), pp 788–796 DOI: 10.1021/ar050104k

Incorporation of either molybdenum or tungsten into formate dehydrogenase from Desulfovibrio alaskensis NCIMB 13491; EPR assignment of the proximal iron-sulfur cluster to the pterin cofactor in formate dehydrogenases from sulfate-reducing bacteria

J Biol Inorg Chem (2004) 9: 145–151 DOI 10.1007/s00775-003-0506-z

Electron transfer chains in sulfate reducing bacteria

Dissertação para a obtenção de grau de doutor em Bioquímica pelo Instituto de Tecnologia Química e Biológica. Universidade Nova de Lisboa.