Navegando por Palavras-chave "Toxins"

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    Análise das sequências de nucleotídeos de novos subtipos de toxinas e proteínas de anêmonas do mar por sequenciamento de RNA de nova geração
    (Universidade Federal de São Paulo (UNIFESP), 2017-07-31) Boralli, Leandro Augusto Freire [UNIFESP]; Kerkis, Irina [UNIFESP]; Zaharenko, André Junqueira; http://lattes.cnpq.br/3955659940007123; http://lattes.cnpq.br/4302687618153569; http://lattes.cnpq.br/8506788466669898; Universidade Federal de São Paulo (UNIFESP)
    Sea anemones are sessile organisms that employ a venomous apparatus (preferably located in their tentacles) to produce and inoculate paralyzing toxins in their prey or to defend themselves. Our group recently contributed to the characterization of the peptidoma of 3 species of sea anemones, showing that the molecular diversity of the toxins of these organisms is much higher than expected. From the point of view of the nucleotide information obtained from anemones, few species were investigated in detail, revealing that at the moment only a small fraction of the toxic arsenal of the cnidarians was investigated. In addition, new structural proteins that occur in anemones present structural and genetic similarity to proteins of derived organisms, such as vertebrates. In this sense, we intend to analyze and compare the transcriptome of two populations of the Brazilian anemone Bunodosoma caissarum, a population of the São Paulo coast and another population located in the isolated São Pedro and São Paulo archipelago. This analysis will be done through the sequencing of new generation RNA, by the Illumina system. With this sequencing and with bioinformatics analyzes we hope to find information regarding new toxins never before studied in this species and also to analyze the differences in the expression profile between the two populations
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    Análise do dimorfismo sexual em venenos da aranha acanthoscurria juruenicola por peptidômica quantitativa
    (Universidade Federal de São Paulo (UNIFESP), 2018-06-28) Almeida, Erika Sayuri Nishiduka Costa De [UNIFESP]; Tashima, Alexandre Keiji [UNIFESP]; http://lattes.cnpq.br/3395922547042342; http://lattes.cnpq.br/9963736748632144; Universidade Federal de São Paulo (UNIFESP)
    Os aracnídeos estão entre os grupos de maior sucesso evolutivo da história do planeta, e um dos fatores de maior importância para isso é a produção de um veneno farmacologicamente complexo, composto por uma coleção de proteínas e peptídeos biologicamente ativos e altamente específicos. Apesar dos peptídeos constituírem grande parte da composição dos venenos, estudos peptidômicos ainda são escassos, consequentemente as identidades e atividades biológicas de muitos desses peptídeos permanecem desconhecidas. Além disso, em diversas espécies de aranhas é observado dimorfismo sexual, o que pode ocasionar diferenças nas composições de venenos de machos e fêmeas. O objetivo deste trabalho foi caracterizar e comparar quantitativamente o perfil peptídico do veneno de espécimes machos e fêmeas da aranha Acanthoscurria juruenicola. Peptídeos nativos foram fracionados por extração em fase sólida e analisados por espectrometria de massas, assim como seus fragmentos gerados pela digestão isolada por 5 enzimas distintas (tripsina, quimotripsina, termolisina, GluC e Aspn). Os dados espectrais foram submetidos a análise de novo, busca em banco de dados de transcriptoma de glândula e sobreposição das clivagens utilizando ferramentas de bioinformática. Dentre 11 sequências maduras de toxinas completamente mapeadas, 8 eram novos peptídeos ricos em cisteínas, apresentando entre 3 a 5 ligações dissulfeto. Buscas em bancos de sequências de A. geniculata e Araneae resultaram em mais 24 proteínas homólogas identificadas. Observamos dimorfismo sexual no veneno: a concentração total de toxinas nos venenos das fêmeas foi aproximadamente 5 vezes superior à dos machos e apresentaram peptídeos com significativa expressão diferencial. Uma das toxinas de maior expressão em fêmeas, a U2TRTXAj1b, de massa molecular 4,9 kDa e 3 ligações dissulfeto, foi fracionada por cromatografia de filtração em gel. Essa toxina apresentou atividade citotóxica contra aproximadamente 44% das células de melanoma da linhagem A375 em ensaios de MTT em concentração de 3,8 μM. Esses resultados podem evidenciar diferenças em toxicidade e comportamento biológico de acordo com o gênero do animal, além de embasar a potencial aplicação biotecnológica desses peptídeos na área farmacológica.
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    Análise do transcriptoma da glândula produtora de veneno de Loxosceles intermedia (aranha marrom): perfil de expressão e identificação de novas toxinas
    (Universidade Federal de São Paulo (UNIFESP), 2010-07-28) Gremski, Luiza Helena [UNIFESP]; Veiga, Silvio Sanches [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Loxosceles genus spiders are responsible for accidents all over the world and have clinical importance in the South of Brazil. The venom of these spiders is made up of several toxins, including proteins, which are responsible for the clinical pattern called loxoscelism. To describe the transcriptional profile of the L. intermedia venom gland, we generated a wide cDNA library, and its transcripts were functionally and structurally analyzed. After initial analyses, 1,843 ESTs produced readable sequences that were grouped into 538 clusters, 281 of which were singletons. Nine hundred eighty-five reads (53% of total ESTs) matched to known proteins. Similarity searches showed that toxinencoding transcripts totalize 43% of the total library and comprise a great number of ESTs. The most frequent toxins were from the LiTx family, which are known for their insecticidal activity. Both phospholipase-D and astacin-like metalloproteases toxins account for approximately 9% of total transcripts. Toxins components such as serine proteases, hyaluronidases and venom allergens were also found but with minor representation. Almost 10% of the ESTs encode for proteins involved in cellular processes. This work also describes the stages for cloning, heterologous expression and purification of a cDNA similar to a protease inhibitor identified in the cDNA library. It is known that proteins belonging to this family have an application potential as antithrombotic drugs, acting as therapeutic agents that influences the activity of coagulation factors. These data provide an important overview of the L. intermedia venom gland expression scenario, revealed significant differences from profiles of other spiders from the Loxosceles genus and describe the production of a novel recombinant toxin.
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    Gene expression analysis by ESTs sequencing of the Brazilian frog Phyllomedusa nordestina skin glands
    (Elsevier B.V., 2013-01-01) Neiva, Márcia [UNIFESP]; Vargas, D. C.; Conceicao, K.; Radis-Baptista, G.; Assakura, M. T.; Jared, Carlos [UNIFESP]; Hayashi, Mirian Akemi Furuie [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Inst Butantan; Univ Fed Ceara
    The subfamily Phyllomedusinae has attracted a great interest of many researchers mainly due to the high diversity of these frog species and plethora of pharmacological activities frequently observed for their skin secretions. Despite of this fact, mainly for new species, limited information is available regarding the molecular composition of these skin secretions and the cellular components involved in their production. Phyllomedusa nordestina is a recently described Brazilian frog species also popularly known as 'tree-frogs'. Aiming at contributing to the biological knowledge of this species, we show here the gene expression profile of this frog skin secretion using a global ESTs analysis of a cDNA library. the marked aspect of this analysis revealed a significant higher transcriptional level of the opioid peptide dermorphins in P. nordestina skin secretion than in Phyllomedusa hypochondrialis, which is its closest related species, belonging both to the same phylogenetic group. Precursors of bioactive peptides as dermaseptins, phylloseptins, tryptophyllins, and bradykinin-like peptideswere also found in this library. Transcripts encoding proteins related to ordinary cellular functions and pathways were also described. Some of them are chiefly involved in the production of the skin secretion. Taken together, the data reported here constitute a contribution to the characterization of the molecular diversity of gene-encoded polypeptides with potential possibility of pharmacological exploitation. the transcriptional composition of the skin secretion may also help to give the necessary support for the definition of P. nordestina as a new species, which actually relies basically on frog morphological characteristics and geographical distribution. (c) 2012 Elsevier B.V. All rights reserved.