Abstract:
:Purified GP57/51, a Trypanosoma cruzi glycoprotein earlier identified as a major antigen in infected humans, was subjected to N-terminal sequence analysis. Alignment of the first 30 amino acids revealed that its N-terminal region is virtually identical to that reported for a cysteine-proteinase isolated from the Tulahuen strain, including the presence of active site cysteine at position 25. The finding of serine at position 24 of GP57/51 (Y strain) has further increased the homology between this protozoan antigen with other members of the eukaryotic family of cysteine proteases, including human cathepsin L. Functional analysis of GP57/51 indicated that the antigen is indeed an active thiol proteinase, which is active across a wide pH range (5-7.5). This was shown using either human IgG or gelatin substrates co-polymerized into polyacrylamide gels prepared for electrophoresis, and also by enzyme assays peformed with the synthetic substrate Z-phe-arg-NMec. The enzyme was activated by thiol containing reagents, and was strongly inhibited by low concentrations of E-64 (IC50 0.1 microM), cystatin (IC50 1 microM), leupeptin (IC50 0.1 microM) and antipain (IC50 0.1 microM). Monoclonal antibodies directed against distinct epitopes of GP57/51 absorbed the hydrolytic activity from purified preparations, demonstrating that the antigenic and enzymatic activities were indeed expressed by the same molecular entities. The subcellular localization of immunoreactive molecules was investigated by electron microscopy; immunogold staining was conspicuously found in vesicles belonging to the endosomal-lysosomal system, in tissue culture trypomastigotes as well as in epimastigotes. The possibility that this highly antigenic protease is actively secreted and/or leaked out of damaged parasites is under investigation; its release to tissues and to the circulation may contribute to pathology, considering that it (i) can degrade proteins across a wide pH range and (ii) stimulates immune T cells from chronic chagasic patients.
journal_name
Mol Biochem Parasitoljournal_title
Molecular and biochemical parasitologyauthors
Murta AC,Persechini PM,Padron Tde S,de Souza W,Guimarães JA,Scharfstein Jdoi
10.1016/0166-6851(90)90127-8subject
Has Abstractpub_date
1990-11-01 00:00:00pages
27-38issue
1eissn
0166-6851issn
1872-9428pii
0166-6851(90)90127-8journal_volume
43pub_type
杂志文章abstract::Genetic variation among malaria parasites has important consequences with regard to drug resistance, pathogenicity, immunity, transmission, and speciation. In this regard, malaria parasites have been shown to display a high degree of inter- and intra-species genetic divergence. The nuclear genomes of Plasmodium falcip...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/s0166-6851(98)00093-0
更新日期:1998-09-01 00:00:00
abstract::Entamoeba histolytica genomic organization and putative promoter elements appear to be distinct from both metazoan and better characterized protozoan organisms. The recent development of DNA-mediated transfection for E. histolytica enabled characterization of cis-acting promoter elements required for gene expression. ...
journal_title:Molecular and biochemical parasitology
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doi:10.1016/s0166-6851(96)02614-x
更新日期:1996-06-01 00:00:00
abstract::The influence of growth in the presence of nifurtimox on total lipids of Trypanosoma cruzi epimastigotes was determined. Nifurtimox-treated organisms showed greater amounts of unsaturated fatty acids as compared with control cells. 18:2 was the major component in the total esterified lipid fraction. Similar results we...
journal_title:Molecular and biochemical parasitology
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doi:10.1016/0166-6851(86)90127-1
更新日期:1986-12-01 00:00:00
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journal_title:Molecular and biochemical parasitology
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abstract::We have compared a total of 44 recognition sites for 12 restriction endonucleases on the 20 kilobase pair maxi-circle of kinetoplast DNA from nine Trypanosoma brucei stocks, four which are known to be infective to man (tow 'gambiense' and two 'rhodesiense' variants). In addition to five polymorphic sites, these DNAs d...
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journal_title:Molecular and biochemical parasitology
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journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(86)90102-7
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journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
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更新日期:2007-07-01 00:00:00
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journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
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更新日期:1996-02-01 00:00:00
abstract::The in vitro-released 'excretory/secretory' (ES) and somatic antigens of the third stage (infective) larva of Anisakis simplex were characterised by radioiodination, immunoprecipitation, and sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Oral infection with the parasite elicited a substantial IgG antibody...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
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更新日期:1988-10-01 00:00:00
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journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
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abstract::The glycosylphosphatidylinositol (GPI)-anchored variant surface glycoprotein (VSG) of Trypanosoma brucei is the most abundant GPI-anchored protein expressed on any cell, and is an essential virulence factor. To determine what structural features affect efficient expression of VSG, we made a series of mutations in two ...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/s0166-6851(03)00055-0
更新日期:2003-05-01 00:00:00
abstract::Plasmodium falciparum invades human erythrocytes by redundant pathways. Unlike Plasmodium vivax that has one Duffy Binding-Like (DBL) receptor, P. falciparum has four members of the DBL receptor family. Furthermore, one of these DBL genes, BAEBL, has polymorphisms at four amino acids in region II; each polymorphism bi...
journal_title:Molecular and biochemical parasitology
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更新日期:2009-11-01 00:00:00
abstract::Phosphatidylcholine is the most abundant phospholipid in the membranes of the human parasite Leishmania. The metabolic pathways leading to its biosynthesis are likely to play a critical role in parasite development and survival and may offer a good target for antileishmanial chemotherapy. Phosphatidylcholine synthesis...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/s0166-6851(02)00220-7
更新日期:2002-11-01 00:00:00
abstract::The influence of pH on the activity of purified pyruvate kinase (ATP:pyruvate 2-O-phosphotransferase, EC 2.7.1.40) from Trypanosoma brucei has been studied. The Km for the coenzyme ADP is pH-dependent and shows the involvement of a dissociable group on the free enzyme with a pKa of 6.5-6.7. The cooperative interaction...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(81)90032-3
更新日期:1981-11-01 00:00:00
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journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
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更新日期:2004-12-01 00:00:00
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journal_title:Molecular and biochemical parasitology
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journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
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更新日期:2012-03-01 00:00:00
abstract::Two NAD(H)-dependent malate dehydrogenase (MDH) isoenzymes were detected in Phytomonas isolated from the lactiferous tubes of Euphorbia characias. The total specific activity in crude extracts using oxaloacetate as substrate was 3.3 U mg-1 of protein. The two isoenzymes had isoelectric points of 6.0 and 7.2, respectiv...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/s0166-6851(97)00100-x
更新日期:1997-10-01 00:00:00
abstract::Glutamate-cysteine ligase (GCL) is a heterodimer enzyme composed of a catalytic subunit (GCLC) and a modifier subunit (GCLM). This enzyme catalyses the synthesis of γ-glutamylcysteine, a precursor of glutathione. cDNAs of the putative glutamate-cysteine ligase catalytic (Ace-GCLC) and modifier subunits (Ace-GCLM) of A...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/j.molbiopara.2014.07.003
更新日期:2014-08-01 00:00:00
abstract::The DNA contents of three different Trypanosoma cruzi strains were compared by direct microfluorometry. The maximal difference found was 40% of the lowest value. Two of the cloned strains, reported in an earlier study to differ by 48% in their total DNA content, showed a difference of 33%. The kinetoplast of the Y str...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(89)90202-8
更新日期:1989-08-01 00:00:00
abstract::Intra-erythrocytic Plasmodium parasites digest host cell haemoglobin and use the liberated amino acids for protein synthesis. Although several endoproteases (aspartic, cysteine, and metallo-) have been shown to be involved in the initial stages of haemoglobin degradation, little is known about the steps immediately be...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
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更新日期:2001-09-28 00:00:00
abstract::Faecal metabolite profiling, though in its infancy, allows for investigation of complex metabolic interactions between gastrointestinal infections or diseases and host health. In the present study, we describe a faecal metabolite extraction method for untargeted gas chromatography-mass spectrometry (GC-MS) analysis us...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
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更新日期:2012-10-01 00:00:00
abstract::Toxoplasma gondii is an obligate intracellular parasite that causes toxoplasmosis in humans and animals. To invade host cells, T. gondii deploys the contents of its apically oriented secretory organelles that include the micronemes. Contained within the micronemes are proteins that possess adhesive motifs resembling t...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/j.molbiopara.2003.12.001
更新日期:2004-04-01 00:00:00
abstract::We have examined changes in the relative synthesis of individual proteins in promastigotes of Leishmania major subjected to decreasing serum levels in vitro. We observed increases in the relative synthesis of the putative heat-shock proteins of 82 and 70 kDa and of proteins of 79 and 41 kDa but decreases in the synthe...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(89)90136-9
更新日期:1989-06-01 00:00:00
abstract::GRA3 is a 30-kDa protein located inside the dense granules of Toxoplasma gondii. Following invasion and exocytosis of dense granules within the parasitophorous vacuole, GRA3 becomes associated with the parasitophorous vacuolar membrane (PVM) and extensions of the PVM which protrude into the cytoplasm. A partial cDNA e...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
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更新日期:1994-12-01 00:00:00
abstract::Surface proteins of male and female gametes of Plasmodium gallinaceum were radioiodinated by the lactoperoxidase method, immunoprecipitated with stage specific antisera and separated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Stage specificity of the surface antigens was further studied by competiti...
journal_title:Molecular and biochemical parasitology
pub_type: 杂志文章
doi:10.1016/0166-6851(84)90061-6
更新日期:1984-04-01 00:00:00