PATRICK JACK SPENCER

PATRICK JACK SPENCER

(Fonte: Lattes)

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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Characterization and evaluation of the enzymatic activity of tetanus toxin submitted to cobalt-60 gamma radiation
2021 - SARTORI, GISELLE P.; COSTA, ANDREA da; MACARINI, FERNANDO L. dos S.; MARIANO, DOUGLAS O.C.; PIMENTA, DANIEL C.; SPENCER, PATRICK J.; NALI, LUIZ H. da S.; GALISTEO JUNIOR, ANDRES J.
Background Tetanus toxin blocks the release of the inhibitory neurotransmitters in the central nervous system and causes tetanus and its main form of prevention is through vaccination. The vaccine is produced by inactivation of tetanus toxin with formaldehyde, which may cause side effects. An alternative way is the use of ionizing radiation for inactivation of the toxin and also to improve the potential immunogenic response and to reduce the post-vaccination side effects. Therefore, the aim of this study was to characterize the tetanus toxin structure after different doses of ionizing radiation of 60Co. Methods Irradiated and native tetanus toxin was characterized by SDS PAGE in reducing and non-reducing conditions and MALD-TOF. Enzymatic activity was measured by FRET substrate. Also, antigenic properties were assessed by ELISA and Western Blot data. Results Characterization analysis revealed gradual modification on the tetanus toxin structure according to doses increase. Also, fragmentation and possible aggregations of the protein fragments were observed in higher doses. In the analysis of peptide preservation by enzymatic digestion and mass spectrometry, there was a slight modification in the identification up to the dose of 4 kGy. At subsequent doses, peptide identification was minimal. The analysis of the enzymatic activity by fluorescence showed 35 % attenuation in the activity even at higher doses. In the antigenic evaluation, anti-tetanus toxin antibodies were detected against the irradiated toxins at the different doses, with a gradual decrease as the dose increased, but remaining at satisfactory levels. Conclusion Ionizing radiation promoted structural changes in the tetanus toxin such as fragmentation and/or aggregation and attenuation of enzymatic activity as the dose increased, but antigenic recognition of the toxin remained at good levels indicating its possible use as an immunogen. However, studies of enzymatic activity of tetanus toxin irradiated with doses above 8 kGy should be further analyzed.
Hypanus americanus mucus
2020 - COELHO, GUILHERME R.; PREZOTTO NETO, JOSE P.; BARBOSA, FERNANDA C.; SANTOS, RAFAEL S.; BRIGATTE, PATRICIA; SPENCER, PATRICK J.; SAMPAIO, SANDRA C.; D'AMELIO, FERNANDA; PIMENTA, DANIEL C.; SCIANI, JULIANA M.
Fish skin plays important biological roles, such as the control of the osmotic pressure gradient, protection against mechanical forces and microorganism infections. The mucus, on the other hand, is a rich and complex fluid, important for the fish acting as innate immunity system, swimming and nutrition. The elasmobranch epidermis is characterized mainly by mucus secretory cells, and marine stingrays have already been described to present secretory glands spread throughout the body. Little is known about the biochemical composition of the stingray mucus, but recent studies denoted the importance of mucus in the envenomation process. Stingrays venom are largely studied due the human medical importance of envenoming caused by sting puncture, that evolve with local inflammation and necrosis, and these toxic events can be correlated to the chemical composition of the sting skin, according to the literature. Aiming to analyse the mucus composition, a new non-invasive mucus collection method was developed that focused on peptides and proteins, and biological assays were performed to analyze preliminary toxic and immune activities of the Hypanus americanus mucus. Pathophysiological characterization showed the presence of peptidases on mucus, as well that the induction of edema and leukocyte recruitment in mice. The fractionated mucus improved phagocytosis on macrophages and showed antimicrobial activity against T. rubrum, C. neoformans and C. albicans in vitro. The proteomic analyses showed the presence of immune-related proteins like actin, histones, hemoglobin, and ribosomal proteins. This protein pattern is similar to those reported for other fish mucus and stingray venom. This is the first report depicting the Hypanus stingray mucus composition, highlighting its biochemical composition and importance for the stingray immune system and the possible role on the envenomation process.
Paratrygon aiereba irradiated anti-mucus serum reduce edematogenic activity induced in experimental model
2020 - THOMAZI, GABRIELA O.C.; COSTA, ANDREA da; RODRIGUES, JAQUELINE P.; ALVES, GLAUCIE J.; PREZOTTO NETO, JOSE P.; TURIBIO, THOMPSON de O.; ROCHA, ANDRE M.; AIRES, RAQUEL da S.; SEIBERT, CARLA S.; SPENCER, PATRICK J.; GALISTEO JUNIOR, ANDRES J.; ANDRADE JUNIOR, HEITOR F. de; NASCIMENTO, NANCI do
Accidents by freshwater stingrays are common in northern Brazil, there is no specific therapy for high morbidity and local tissue destruction. The irradiation of venoms and toxins by ionizing radiation has been used to produce appropriate immunogens for the production of antisera. We planned to study the efficacy of stinging mucus irradiation in the production of antisera, with serum neutralization assays of edematogenic activity and quantification of cytokines performed in animal models of immunization with native and irradiated mucus of Paratrygon aiereba, a large freshwater stingray. Antiserum potency and its cross-reactivity with mucus from other freshwater stingrays were detected by ELISA. Immunization models demonstrated the ability to stimulate a strong humoral response with elevated levels of serum IgG detectable by ELISA, and both native and irradiated mucus were immunogenic and capable of recognizing mucus proteins from other freshwater neotropical stingrays. Mucus P. aiereba causes cellular and humoral adaptive immune responses in cells of immunized mice producing antibodies and cytokines such as TNF-α, IL-6 and IL-17. Rabbit antisera immunized with mucus from P. aiereba irradiated at 2 kGy showed a significant reduction of mucus-induced edematogenic activity in mice. Our data suggest that the use of antisera against freshwater stingray mucus show the possibility of specific therapy for these accidents.
Protein identification from the parotoid macrogland secretion of Duttaphrynus melanostictus
2019 - MARIANO, DOUGLAS O.C.; MESSIAS, MARCELA D.G.; SPENCER, PATRICK J.; PIMENTA, DANIEL C.
Background: Bufonid parotoid macrogland secretion contains several low molecular mass molecules, such as alkaloids and steroids. Nevertheless, its protein content is poorly understood. Herein, we applied a sample preparation methodology that allows the analysis of viscous matrices in order to examine its proteins. Methods: Duttaphrynus melanostictus parotoid macrogland secretion was submitted to ion-exchange batch sample preparation, yielding two fractions: salt-displaced fraction and acid-displaced fraction. Each sample was then fractionated by anionic-exchange chromatography, followed by in-solution proteomic analysis. Results: Forty-two proteins could be identified, such as acyl-CoA-binding protein, alcohol dehydrogenase, calmodulin, galectin and histone. Moreover, de novo analyses yielded 153 peptides, whereas BLAST analyses corroborated some of the proteomicidentified proteins. Furthermore, the de novo peptide analyses indicate the presence of proteins related to apoptosis, cellular structure, catalysis and transport processes. Conclusions: Proper sample preparation allowed the proteomic and de novo identification of different proteins in the D. melanostictus parotoid macrogland secretion. These results may increase the knowledge about the universe of molecules that compose amphibian skin secretion, as well as to understand their biological/physiological role in the granular gland.
Isolation and biochemical characterization of bradykinin-potentiating peptides from Bitis gabonica rhinoceros
2017 - FUCASE, TAMARA M.; SCIANI, JULIANA M.; CAVALCANTE, INGRID; VIALA, VINCENT L.; CHAGAS, BRUNO B.; PIMENTA, DANIEL C.; SPENCER, PATRICK J.
Background: Venoms represent a still underexplored reservoir of bioactive components that might mitigate or cure diseases in conditions in which conventional therapy is ineffective. The bradykinin-potentiating peptides (BPPs) comprise a class of angiotensin-I converting enzyme (ACE) inhibitors. The BPPs usually consist of oligopeptides with 5 to 13 residues with a high number of proline residues and the tripeptide Ile-Pro-Pro (IPP-tripeptide) in the C-terminus region and have a conserved N-terminal pyroglutamate residue. As a whole, the action of the BPPs on prey and snakebite victims results in the decrease of the blood pressure. The aim of this work was to isolate and characterize novel BPPs from the venom of Bitis gabonica rhinoceros. Methods: The crude venom of B. g. rhinoceros was fractionated by size exclusion chromatography and the peptide fraction (<7 kDa) was separated by reverse phase chromatography (RP-HPLC) and analyzed by ESI-IT-TOF-MS/MS. One new BPP was identified, synthetized and assayed for ACE inhibition and, in vivo, for edema potentiation. Results: Typical BPP signatures were identified in three RP-HPLC fractions. CID fragmentation presented the usual y-ion of the terminal P-P fragment as a predominant signal at m/z 213.1. De novo peptide sequencing identified one Bothrops-like BPP and one new BPP sequence. The new BPP was synthesized and showed poor inhibition over ACE, but displayed significant bradykinin-induced edema potentiation. Conclusions: So far, few BPPs are described in Viperinae, and based on the sequenced peptides, two non-canonical sequences were detected. The possible clinical role of this new peptides remains unclear.
Isolation and characterization of bradykinin potentiating peptides from Agkistrodon bilineatus venom
2016 - MUNAWAR, AISHA; ZAHID, ANUM; NEGM, AMR; AKREM, AHMED; SPENCER, PATRICK; BETZEL, CHRISTIAN
New insights into the structural characteristics of irradiated crotamine
2015 - OLIVEIRA, KARINA C.; SPENCER, PATRICK J.; FERREIRA JUNIOR, RUI S.; NASCIMENTO, NANCI