Publications (2)2.12 Total impact
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ABSTRACT: Toxoplasma gondii is an intracellular protozoan parasite of worldwide distribution. Parasites that habour a complete antigenic profile, that is necessary for the serological diagnosis of human Toxoplasma infections, are provided by in vivo culture methods only. It seems that the host immune pressure is responsible for the expression of a total antigen pattern. Thus, in most laboratories the asexual proliferative stage of the parasite, the tachyzoite, is maintained by successive intraperitoneal passages in highly susceptible animals such as mice. We would like to develop an in vitro method to provide sufficient amounts of high quality parasite antigen suitable for diagnosis of Toxoplasmosis. Using the RAPD-PCR (random amplified polymorphic DNA-PCR) technique, we were able to show that during different culture conditions (in vivo and in vitro culture) the parasites undergo no clonal selection. That means the entire parasite population changes the protein expression pattern due to the in vitro culture conditions. Based on the result described previously the work could be continued as follows. One strategy could be to simulate the host immune pressure during the in vitro cultivation of the tachyzoites. A more convinced approach may be the production of recombinant parasite antigens useful for diagnosis of a Toxoplasma infection in human adults and newborns.ALTEX. 02/1998; 15(5):37-39.
Article: Expression, purification, and biochemical characterization of a recombinant Iectin of Sarcocystis muris (Apicomplexa) cyst merozoites[show abstract] [hide abstract]
ABSTRACT: The mature major microneme protein of Sarcocystis muris cyst merozoites, which is known as a dimeric lectin with high affinity to galactose and some of its derivatives, was expressed in Escherichia coli as a histidine-tagged fusion protein. The recombinant polypeptide, which was recognized by a monoclonal antibody directed against the native lectin, was purified from inclusion bodies after solubilization and refolding, using a combination of metal chelate and lactose affinity chromatography. The apparent molecular mass of the refolded polypeptide as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoreses was 16 kDa, whereas gel filtration chromatography clearly demonstrated that the recombinant protein, like its native counterpart, exists as a homodimer of two non-covalently associated subunits. Inhibition of haemagglutination suggests that the combining site of the recombinant lectin recognizes N-acetyl-galactosamine as the dominant sugar, thus confirming the correct folding of the monosaccharide combining site in the renatured lectin. To the best of our knowledge, this work represents the first reported detailed characterization of a recombinant lectin from apicomplexan parasites, and may contribute to a better understanding of the process of host cell recognition and invasion by these obligate intracellular protozoa.Glycoconjugate Journal 01/1998; 15(2):147-153. · 2.12 Impact Factor