Data/hora: 08/06/2024 14:45:23

Provedor de dados: | 65
País: | Brazil
Título: | Metabolic pathway of oligosaccharides in sorghum honeydew caused by Claviceps africana
Autores: | Bogo,Amauri; Mantle,Peter.
Data: | 2008-08-01
Ano: | 2008
Palavras-chave: | Biosynthesis; Metabolic pathway; Oligosaccharides; Ergot.
Resumo: | The occurrence of the alditol oligosaccharides in the Claviceps afriana honeydew is partly as a rational expression of the pathogen's selective nutritive metabolism of the sucrose supplied by the host plant. The experiments were carried out in laboratory and when 14C-D-sucrose, 14C-D-fructose or 14C-D-mannitol radiolabelled saccharides were incorporated into: a) sorghum plant infected by C. africana, b) whole and macereted micelia tissue and c) cell-free honeydew of C. africana, it was observed that the glucose moiety of sucrose was not involved in oligosaccharides formation. Glucose was used by the pathogen as nutritional source. Part of the unused fructose moiety was reduced to mannitol by the pathogen's enzymes which was also excreted into honeydew where reductase activity accepted 14C mannitol. The mannitol was linked with fructose in a 2-position synthesizing the disaccharide 1-beta-D-fructofuranosyl-D-mannitol and then the process was repeated by the mannitol moiety of the disaccharide to yield the trisaccharide 1,6-di-beta-D-fructofuranosyl-D-mannitol, which became dominant. The direct formation of alditol saccharides from monosaccharides in this way seems to be unique to C. africana, contrasting with the fructosyl transfer from sucrose to sucrose which is usual in others ergot parasites.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782008000400008
Editor: | Universidade Federal de Santa Maria
Relação: | 10.1590/S0103-84782008000400008
Formato: | text/html
Fonte: | Ciência Rural  v.38 n.4 2008
Fonte: | info:eu-repo/semantics/openAccess