A DNA-PROBE TO IDENTIFY ENTEROTOXIGENIC ESCHERICHIA-COLI EXPRESSING PCF0159 COLONIZATION FACTOR

The expression of PCF0159 fimbriae by a ETEC Escherichia coli strain was blocked by using transposon TnphoA. The plasmidial DNA sequence which includes the insertion of the transposon was cloned and used as a DNA probe against E. coli strains expressing different colonization factors and enterotoxins. The DNA probe was specific only for those strains belonging either to the serotype 0159:H4 or carrier strains which expressed PCF0159 fimbriae operons.18335536

TRYPANOSOMA-CRUZI - CHARACTERIZATION of INVITRO and INVIVO SYNTHESIZED POLYPEPTIDES FROM EPIMASTIGOTE FORMS of DIFFERENT STRAINS

ESCOLA PAULISTA MED,DEPT MICROBIOL IMMUNOL & PARASITOL,BR-04023 São Paulo,SP,BRAZILESCOLA PAULISTA MED,DEPT MICROBIOL IMMUNOL & PARASITOL,BR-04023 São Paulo,SP,BRAZILWeb of Scienc

PROTEIN-SYNTHESIS in ISOLATED SYMBIONTS FROM the FLAGELLATE PROTOZOAN CRITHIDIA-DEANEI

ESCOLA PAULISTA MED,DEPT MICROBIOL IMMUNOL & PARASITOL,RUA BOTUCATU 862,BR-04023 São Paulo,SP,BRAZILESCOLA PAULISTA MED,DEPT MICROBIOL IMMUNOL & PARASITOL,RUA BOTUCATU 862,BR-04023 São Paulo,SP,BRAZILWeb of Scienc

RECOMBINANT TRYPANOSOMA-CRUZI ANTIGENS and CHAGAS-DISEASE DIAGNOSIS - ANALYSIS of A WORKSHOP

A workshop organized by the Ibero-American Project of Biotechnology evaluated the diagnostic potential of several cloned Trypanosoma cruzi recombinant antigens for Chagas' disease serodiagnosis. A set of recombinants, Antigen 2, Antigen 13, SAPA, H49, A13, JL5, JL7, JL8, JL9, and RA1 provided by three different South American laboratories were probed with a panel of 236 South American serum samples. Antigens JL7, H49, Antigen 2, and A13 scored as the best diagnostic recombinant reagents. the results suggested that the main advantage of using cloned peptides for chronic Chagas' disease diagnosis resided in their highly specific immunoreactive properties.LAB FLEURY, São Paulo, BRAZILESCOLA PAULISTA MED SCH, DISCIPLINA PARASITOL, BR-04023 São Paulo, BRAZILFDN CAMPOMAR, INST INVEST BIOQUIM, BUENOS AIRES, ARGENTINAFDN OSWALDO CRUZ, DEPT BIOL MOLEC, RIO de JANEIRO, BRAZILUNIV SIMON BOLIVAR, CARACAS, VENEZUELAESCOLA PAULISTA MED SCH, DISCIPLINA PARASITOL, BR-04023 São Paulo, BRAZILWeb of Scienc

Identification of a domain of Trypanosoma cruzi metacyclic trypomastigote surface molecule gp82 required for attachment and invasion of mammalian cells

Recombinant proteins and synthetic peptides representing various sequences of gp82, a surface glycoprotein of Trypanosoma cruzi metacyclic trypomastigotes implicated in mammalian cell invasion, were used in this study aiming at the identification of the domain(s) of this molecule required for interaction with target cells. Invasion of cultured HeLa cells by metacyclic trypomastigotes was inhibited by about 80% in the presence of native gp82 or the corresponding recombinant construct J18. Inhibition by recombinant proteins J18a and J18b, containing respectively the N-terminal and the C-terminal portions of gp82, was on the order of 30% and 65%. As compared to J18b (amino acids 224-516), the truncated gp82 fragments J18b1 (amino acids 303-516) and J18b2 (amino acids 357-516) displayed lower inhibitory effect (similar to 40% and similar to 15%, respectively). Compatible with these observations, we found that the recombinant protein J18b, but not J18a or J18b2, binds to HeLa cells in a dose-dependent and saturable fashion. Experiments with ten overlapping synthetic peptides, representing the gp82 portion spanning amino acids 224-333, showed that peptides 4 (amino acids 254-273) and 8 (amino acids 294-313) have significant inhibitory activity on HeLa cell invasion by metacyclic forms. All these results indicate that the portion of gp82 required for mammalian cell attachment and invasion is located in the central domain of the molecule.Universidade Federal de São Paulo,ESCOLA PAULISTA MED,DEPT MICROBIOL IMUNOL & PARASITOL,BR-04023062 São Paulo,BRAZILUniversidade Federal de São Paulo,ESCOLA PAULISTA MED,DEPT BIOFIS,São Paulo,BRAZILUniversidade Federal de São Paulo,ESCOLA PAULISTA MED,DEPT MICROBIOL IMUNOL & PARASITOL,BR-04023062 São Paulo,BRAZILUniversidade Federal de São Paulo,ESCOLA PAULISTA MED,DEPT BIOFIS,São Paulo,BRAZILWeb of Scienc

Cloning and characterization of a gene encoding a novel immunodominant antigen of Trypanosoma cruzi

A Trypanosoma cruzi genomic expression library was screened with a pool of sera obtained from chronic chagasic patients. the recombinant antigen (Tc40) isolated from this library reacted with a large number of serum samples of chronic chagasic patients, suggesting that the presence of anti-Tc40 antibodies may be specifically associated to Chagas' disease. the full-length sequence of the Tc40 gene was determined after isolation of genomic and cDNA clones. the Tc40 cDNA includes a large open reading frame (2745 bp-long) that encodes a polypeptide of 100 kDa without any homology with previously described T. cruzi sequences. in contrast with other T. cruzi antigens whose immunodominant B-cell epitopes are composed by amino acid repetitive motifs, Tc40 does not show any amino acid repetition. Antibodies against the Tc40 recombinant protein reacted with three native polypeptides of 100, 41 and 38 kDa which are lightly associated with membranes or cytoskeleton and expressed in all developmental stages of the parasite life cycle. A transcript of 3.9-kb was detected in Northern blot analysis which is large enough to encode a 100 kDa polypeptide. Tc40 genes were mapped on a chromosomal band of 1.1 Mbp and in a few copies per haploid genome in the G strain. (C) 1997 Elsevier Science B.V.ECOLE NORMALE SUPER LYON,UNITE MIXTE CNRS BIOMERIEUX,F-69364 LYON 07,FRANCELAB BIOMETRIE,CNR,URA 2055,VILLEURBANNE,FRANCEESCOLA PAULISTA MED,DEPT PARASITOL,BR-04023 São Paulo,BRAZILBIOLAB MERIEUX,São Paulo,BRAZILESCOLA PAULISTA MED,DEPT PARASITOL,BR-04023 São Paulo,BRAZILWeb of Scienc

TRYPANOSOMA-CRUZI - CLONING and EXPRESSION of AN ANTIGEN RECOGNIZED BY ACUTE and CHRONIC HUMAN CHAGASIC SERA

HOSP NINOS DR RICARDO GUTIERREZ,BUENOS AIRES,ARGENTINAUNIV ESTADUAL CAMPINAS,HOSP CLIN,BR-13100 CAMPINAS,SP,BRAZILUNIV São Paulo,INST TROP MED,São Paulo,BRAZILUNIV FED GOIANIA,FAC MED,GOIANIA,BRAZILWeb of Scienc