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Surface properties related to concanavalin A-induced agglutination. A comparative study of several Entamoeba strains
D Trissl1, A Martínez-Palomo, C Argüello
1Centro de Investigación del IPN, México.
Abstract:
Pathogenic strains of Entamoeba histolytica are more easily agglutinated with concanavalin A (Con A) than strains isolated from human asymptomatic carriers. All three pathogenic strains studied here were found to agglutinate with low concentrations of Con A in contrast to various nonpathogenic axenic strains of amebas, characterized by their ability to grow at room temperature. Our present observations suggest that the extreme susceptibility of pathogenic strains of E. histolytica to agglutinate with Con A is related to their higher capacity for lectin binding and to their lack of detectable repulsive charges at the cell surface. The amount of fluorescein-tagged Con A bound to the surface was much higher in pathogenic strains. Only nonpathogenic strains showed a detectable negative surface charge as studied both by means of cell microelectrophoresis and by labeling cells with cationized ferritin at 0 degrees C. The mobility of surface Con A receptors estimated as the percentage of caps was comparable in all strains. Results of one strain cultured in axenic and monoxenic conditions suggested that bacteria can modify the behaviour of E. histolytica trophozoites by altering surface properties of the amebas.
Insights
Pathogenic Entamoeba histolytica strains bind more readily to concanavalin A (Con A) due to higher lectin binding and fewer repulsive surface charges. Nonpathogenic strains possess a detectable negative surface charge, unlike pathogenic ones.
Area of Science:
- Microbiology
- Cell Biology
- Parasitology
Background:
- Entamoeba histolytica causes amoebiasis, ranging from asymptomatic infections to severe disease.
- Differences in surface properties between pathogenic and nonpathogenic strains are not fully understood.
- Lectins like concanavalin A (Con A) can interact with cell surface carbohydrates, potentially revealing differences in amebic strains.
Purpose of the Study:
- To investigate the differential agglutination of pathogenic and nonpathogenic Entamoeba histolytica strains by concanavalin A (Con A).
- To explore the relationship between Con A agglutination, cell surface charge, and lectin binding capacity in E. histolytica.
Main Methods:
- Agglutination assays using varying concentrations of Con A.
- Quantification of fluorescein-tagged Con A binding to amebic surfaces.
- Cell microelectrophoresis to assess surface charge.
- Labeling with cationized ferritin to detect negative surface charges at low temperatures.
Main Results:
- Pathogenic E. histolytica strains showed significantly higher agglutination with Con A compared to nonpathogenic strains.
- Pathogenic strains exhibited greater binding of fluorescein-tagged Con A.
- Nonpathogenic strains displayed a detectable negative surface charge, absent in pathogenic strains.
- Receptor mobility was comparable across all studied strains.
Conclusions:
- The enhanced agglutination of pathogenic E. histolytica by Con A is linked to increased lectin binding and a lack of repulsive surface charges.
- Surface charge and lectin-binding properties are potential markers differentiating pathogenic from nonpathogenic amebic strains.
- Bacterial presence in monoxenic cultures can influence amebic surface properties and behavior.