PATRICK JACK SPENCER

Resumo

Possui graduação em Ciências Biológicas pela Universidade Presbiteriana Mackenzie (1991), mestrado em Tecnologia Nuclear pela Universidade de São Paulo (1995) e doutorado em Tecnologia Nuclear pela Universidade de São Paulo (2000) tendo sido bolsista sandwich no US Army Medical Research Institute for Infeccious Diseases (98-99). É responsável pelo Biotério de criação e manutenção de animais de laboratório do IPEN. Tem experiência na área de Bioquímica, com ênfase em Proteínas, atuando principalmente nos seguintes temas: veneno, proteínas, bothrops, irradiação e miotoxina.(Texto extraído do Currículo Lattes em 22 dez. 2021)

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Agora exibindo 1 - 4 de 4
  • Artigo IPEN-doc 23048
    Protein profile analysis of two australian snake venoms by one- dimensional gel electrophoresis and MS/MS experiments
    2017 - GEORGIEVA, DESSISLAVA; HILDEBRAND, DIANA; SIMAS, RODRIGO; CORONADO, MONIKA A.; KWIATKOWSKI, MARCEL; SCHLUTER, HARTMUT; ARNI, RAGHUVIR; SPENCER, PATRICK; BETZEL, CHRISTIAN
    The Pseudechis colletti and Pseudechis butleri venoms were analyzed by 1-D gel electrophoresis, followed by mass spectrometric analysis of tryptic peptides obtained from the protein bands. Both venoms contain highly potent pharmacologically active components, which were assigned to the following protein families: basic and acidic phospholipases A2 (PLA2s), L-amino acid oxidases (LAAOs), P-III metalloproteinases (P-III SVMPs), 5’- nucleotidases (5’-NTDs), cysteine-rich secretory proteins (CRISPs), venom nerve growth factors (VNGFs) and post-synaptic neurotoxins. Considerable predominance of PLA2s over other toxins is a characteristic feature of both venoms. The major differences in the venom compositions are the higher concentration of SVMPs and CRISPs in the P. butleri venom, as well as the presence of post-synaptic neurotoxins. Furthermore, the analysis revealed a high concentration of proteins with myotoxic, coagulopathic and apoptotic activities. PLA2s are responsible for the myotoxic and anticoagulant effects observed in patients after envenomation (4). The other protein families, encountered in the two venoms, probably contribute to the major symptoms described for these venoms. These results explain the observed clinical effects of the black snake envenomation. The analyzed venoms contain group P-III metalloproteinases of medical importance with the potency to be used for diagnostic purposes of von Willebrand factor (vWF) disease, for regulation of vWF in thrombosis and haemostasis, for studying the function of the complement system in host defense and in the pathogenesis of diseases. Comparison of venomic data showed similarities in the major venom components of snakes from the genus Pseudechis, resulting in common clinical effects of envenomation, and demonstrating close relationships between venom toxins of Elapidae snakes.
  • Artigo IPEN-doc 20303
    Pseudechis guttatus venom proteome: Insights into evolution and toxin clustering
    2014 - VIALA, VINCENT L.; HILDEBRAND, DIANA; TRUSCH, MARIA; ARNI, RAGHUVIR K.; PIMENTA, DANIEL C.; SCHLUTER, HARTMUT; BETZEL, CHRISTIAN; SPENCER, PATRICK J.
  • Artigo IPEN-doc 17565
    Venom peptide analysis of Vipera ammodytes meridionalis (Viperinae) and Bothrops jararacussu (Crotalinae) demonstrates subfamily-specificity of the peptidome in the family Viperidae
    2011 - MUNAWAR, AISHA; TRUSCH, MARIA; GEORGIEVA, DESSISLAVA; SPENCER, PATRICK; FROCHAUX, VIOLETTE; HARDER, SONKE; ARNI, RAGHUVIR K.; DUHALOV, DEYAN; GENOV, NICOLAY; SCHLUTER, HARTMUT; BETZEL, CHRISTIAN
  • Artigo IPEN-doc 11681
    BE-I-PLA2, a novel acidic phospholipase Asub(2) from Bothrops erythromelas venom: isolation, cloning and characterization as potent anti-platelet and inductor of prostaglandin Isub(2) release by endothelial cells
    2006 - MODESTO, J.C. de A.; SPENCER, PATRICK J.; FRITZEN, MARCIO; VALENCA, RENATA C.; OLIVA, MARIA L.V.; SILVA, MARCIA B. da; TAVASSI, ANA M.C.; GUARNIERI, MIRIAM C.
    A novel acidic Asp49 phospholipase A2 was isolated from Bothrops erythromelas (jararaca malha-de-cascavel) snake venom by four chromatographic steps. BE-I-PLA2 present a molecular weight of 13,649.57 Da as estimated by mass spectrometry. N-terminal and four internal peptides were sequenced, covering around one-third of the complete toxin sequence. The complete BE-I-PLA2 cDNA was cloned from a B. erythromelas venom-gland cDNA library. The cDNA sequence possesses 457 bp and encodes a protein with significant sequence similarity to many other phospholipase A2 from snake venoms. When tested in platelet rich plasma, the enzyme showed a potent inhibitory effect on aggregation induced by arachidonic acid and collagen, but not ADP. On the other hand, BE-I-PLA2 did not modify aggregation in washed platelet. Furthermore, no action of BE-I-PLA2 on the principal platelets receptors was observed. Chemical modification with p-bromophenacyl bromide abolished the enzymatic activity of BE-I-PLA2, but its anti-platelet activity was only partially inhibited. In human umbilical-cord veins endothelial cells, BE-I-PLA2 was neither apoptotic nor proliferative but stimulated endothelial cells to release prostaglandin I2, suggesting an increase of its potential anti-platelet activity in vivo. Further studies are required in order to determine the exact mechanism of action of BE-I-PLA2 in the inhibition of platelet aggregation.