Navegando por Palavras-chave "glycosylphosphatidylinositol"

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    Conservation of genetic linkage between heat shock protein 100 and glycosylphosphatidylinositol-specific phospholipase C in Trypanosoma brucei and Trypanosoma cruzi
    (Elsevier B.V., 1998-07-01) Redpath, M. B.; Carnall, N.; Webb, H.; Courel, M.; Amorim, A.; Guther, MLS; Almeida, MLC de; Carrington, M.; Univ Cambridge; Universidade Federal de São Paulo (UNIFESP); Univ Dundee
    The experiments described in this paper were designed to try and isolate a recombinant DNA clone encoding a Trypanosoma cruzi homologue of the Trypanosoma br brucei glycosylphosphatidylinositol-specific phospholipase C (GPI-PLC) gene. Despite the ready biochemical detection of phospholipase C activities that hydrolyse GPI-anchors of cell surface proteins in T. cruzi, it did not prove possible to isolate any recombinant DNA clones using the T. brucei gpi-plc gene as a probe. On determining the DNA sequence to the 5' side of the gpi-plc gene it was found to be adjacent to a gene that encodes a 100 kDa heat shock protein (HSP100). To investigate whether this linkage between the hsp100 and gpi-plc genes was conserved in T. cruzi, a probe derived from the T. brucei hsp100 gene was used to isolate T. cruzi genomic clones. These were partially sequenced and shown to contain an hsp100 gene. Restriction enzyme fragments located to the 3' side of the T. cruzi hsp100 gene were then sequenced and found to contain a gene that encodes a polypeptide (TcPLC1) that has 46% amino acid sequence identity with the T. brucei GPI-PLC including most of the key residues involved in inositol binding and the catalytic histidine. A recombinant form of TcPLC1 was produced and shown to possess phospholipase C activity towards a GPI-substrate. Thus, the hsp100 and gpi-plc genes are adjacent in T. brucei and this linkage is conserved in T. cruzi. This observation has been used to facilitate the isolation of a clone encoding a T. cruzi phospholipase C gene. (C) 1998 Published by Elsevier Science B.V. All rights reserved.
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    Highly purified glycosylphosphatidylinositols from Trypanosoma cruzi are potent proinflammatory agents
    (Oxford Univ Press, 2000-04-03) Almeida, I. C.; Camargo, M. M.; Procopio, D. O.; Silva, Luiz S. [UNIFESP]; Mehlert, A.; Travassos, Luiz Rodolpho [UNIFESP]; Gazzinelli, R. T.; Ferguson, MAJ; Univ Dundee; Universidade Federal de Minas Gerais (UFMG); Universidade Federal de São Paulo (UNIFESP); Fundacao Oswaldo Cruz
    Intracellular protozoan parasites are potent stimulators of cell-mediated immunity. the induction of macrophage proinflammatory cytokines by Trypanosoma cruzi is considered to be important in controlling the infection and the outcome of Chagas' disease. Here we show that the potent tumour necrosis factor-alpha-, interleukin-12- and nitric oxide-inducing activities of T.cruzi trypomastigote mucins were recovered quantitatively in a highly purified and characterized glycosylphosphatidylinositol (GPI) anchor fraction of this material. the bioactive trypomastigote GPI fraction was compared with a relatively inactive GPI fraction prepared from T.cruzi epimastigote mucins, the trypomastigote GPI structures were found to contain additional galactose residues and unsaturated, instead of saturated, fatty acids in the sn-2 position of the alkyl-acylglycerolipid component. the latter feature is essential for the extreme potency of the trypomastigote GPI fraction, which is at least as active as bacterial endotoxin and Mycoplasma lipopeptide and, therefore, one of the most potent microbial proinflammatory agents known.