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Registro Completo |
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Biblioteca(s): |
Embrapa Meio Norte / UEP-Parnaíba. |
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Data corrente: |
23/01/1996 |
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Data da última atualização: |
23/01/1996 |
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Autoria: |
CARLINI, C. R.; GUIMARAES, J. A. |
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Afiliação: |
Universidade Federal do Rio de Janeiro. |
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Título: |
Plant and microbial toxic proteins as hemilectins: emphasis on canatoxin. |
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Ano de publicação: |
1991 |
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Fonte/Imprenta: |
Toxicon, v.29, n.7, p.791-806, 1991. |
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Idioma: |
Inglês |
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Conteúdo: |
Ribosome-inactivating plant toxic proteins and ADP-ribosylating microbial toxins share a common structural organization. These proteins present domains displaying different biological properties: a target cell membrane-binding component (B-subunit or haptomer) and an enzymatically active component (A-subunit or effectomer). Interactions of these toxins with the target cells are mediated by the hemilectin- like haptomer, which recognizes and specifically binds to a given glycoderivative present at the cell surface. After binding the holoprotein is internalized via endocytosis. Inside the endocytic compartment the toxin is processed to release its effectomer moiety which catalytically modifies a cytoplasmic component, and this step accounts for its toxic effect. The structural relationships between toxic hemilectins and plant lectins are discussed, with emphasis on the example of canatoxin and concanavalin A, both present in the seeds of the jack bean Canavalia ensiformis. Contrary to other plant toxic proteins, which inhibit protein synthesis, canatoxin-induced toxicity includes central nervous system-mediated effects. In vivo as well as in vitro canatoxin acts as lipoxygenase-mediated secretagogue in several types of cells: blood platelets, mast cells, pancreatic islets and synaptosomes. Elucidation of structure vs biological activity relationships of canatoxin and other toxic proteins may provide data for their utilization as pharmacological tools and as therapeutic agents. MenosRibosome-inactivating plant toxic proteins and ADP-ribosylating microbial toxins share a common structural organization. These proteins present domains displaying different biological properties: a target cell membrane-binding component (B-subunit or haptomer) and an enzymatically active component (A-subunit or effectomer). Interactions of these toxins with the target cells are mediated by the hemilectin- like haptomer, which recognizes and specifically binds to a given glycoderivative present at the cell surface. After binding the holoprotein is internalized via endocytosis. Inside the endocytic compartment the toxin is processed to release its effectomer moiety which catalytically modifies a cytoplasmic component, and this step accounts for its toxic effect. The structural relationships between toxic hemilectins and plant lectins are discussed, with emphasis on the example of canatoxin and concanavalin A, both present in the seeds of the jack bean Canavalia ensiformis. Contrary to other plant toxic proteins, which inhibit protein synthesis, canatoxin-induced toxicity includes central nervous system-mediated effects. In vivo as well as in vitro canatoxin acts as lipoxygenase-mediated secretagogue in several types of cells: blood platelets, mast cells, pancreatic islets and synaptosomes. Elucidation of structure vs biological activity relationships of canatoxin and other toxic proteins may provide data for their utilization as pharmacological tools and as therapeutic agent... Mostrar Tudo |
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Palavras-Chave: |
Proteina toxica; Toxic protein. |
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Categoria do assunto: |
-- |
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Marc: |
null
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Registro original: |
Embrapa Meio Norte / UEP-Parnaíba (CPAMN-UEPP) |
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 | Acesso ao texto completo restrito à biblioteca da Embrapa Milho e Sorgo. Para informações adicionais entre em contato com cnpms.biblioteca@embrapa.br. |
Registro Completo
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Biblioteca(s): |
Embrapa Milho e Sorgo. |
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Data corrente: |
26/01/2016 |
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Data da última atualização: |
26/09/2017 |
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Tipo da produção científica: |
Artigo em Periódico Indexado |
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Circulação/Nível: |
B - 1 |
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Autoria: |
PEREIRA, C. M. R.; GOTO, B. T.; SILVA, D. K. A. da; FERREIRA, A. C. de A.; SOUZA, F. A. de; SILVA, G. A. da S.; MAIA, L. C.; OEHL, F. |
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Afiliação: |
FRANCISCO ADRIANO DE SOUZA, CNPMS. |
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Título: |
Acaulospora reducta sp. nov. and A. excavata: two glomeromycotan fungi with pitted spores from Brazil. |
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Ano de publicação: |
2015 |
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Fonte/Imprenta: |
Mycotaxon, Ithaca, v. 130, p. 983-995,Oct./Dec. 2015. |
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DOI: |
10.5248/130.983 |
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Idioma: |
Inglês |
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Conteúdo: |
Acaulospora reducta sp. nov. and A. excavata, both characterized by large pits on their spore surfaces, were found in the semi-humid Atlantic rainforest and semi-arid Caatinga biomes of Northeastern Brazil. Phylogenetic analyses of the ITS regions of the ribosomal gene place the two fungi in two distinct clades within the Acaulosporaceae. Acaulospora reducta has whitish yellow, dark yellow to light brown spores (135–205 um in diam.) and irregularly shaped, often edged to sometimes dumbbell-shaped pits (5.5–19 × 3.5–8.6 um). These large pits have roughened irregular surfaces comprising secondary small pits (c. 0.5 ?m broad and deep) and fine ridges. Spores of A. excavata are ochre to yellow orange (sometimes yellow) and have regular circular to subcircular pits (4–20 × 4–16 um) with smooth pit surfaces. Most recently, A. reducta was also found in the Cerrado biome of Minas Gerais, suggesting its wide distribution in tropical Brazil. |
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Thesagro: |
Genética. |
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Categoria do assunto: |
-- |
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Marc: |
null
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Registro original: |
Embrapa Milho e Sorgo (CNPMS) |
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