Dwyer DM, Chang KP. Surface membrane carbohydrate alterations of a flagellated protozoan mediated by bacterial endosymbiotes.
Proc Natl Acad Sci U S A 1976;
73:852-6. [PMID:
1062797 PMCID:
PMC336017 DOI:
10.1073/pnas.73.3.852]
[Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Crithidia oncopelti, a parasitic trypanosomatid protozoan of insects, normally contains intracellular symbiotic bacteria. As shown earlier, the protozoa can be rid of their endosymbiotes by chloramphenicol, producing a symbiote-free cell line. Here surface-membrane carbohydrate ligands of the symbiote-containing and symbiote-free strains were compared by lectin-mediated agglutination, lectin-ultrastructure localization. [3H] lectin-binding, and fluorescent lectin staining. Symbiote-free organisms consistently had 3-fold higher agglutination titers than symbiote-containing cells with concanavalin A. Conversely, symbiote-containing flagellates had 2- to 3-fold greater agglutination titers with a fucose-binding lectin than symbiote-free organisms. Ultrastructure results showed that more of concanavalin A-horseradish peroxidase-diaminobenzidine reaction product was present at the surface of symbiote-free than on symbiote-containing cells. Treatment with [3H]concanavalin A revealed that surface membrane sites available per cell for [3H]lectin-binding ranged from 6.2 to 7.4 x 10(4) and from 24 to 27 x 10(4) for symbiote-containing and symbiote-free organisms, respectively, i.e., the mean binding level of the latter for the lectin was 3.5 times greater than that of the former. Moreover, symbiote-free cells fluoresced more than symbiote-containing organisms after staining with fluorescein-labeled concanavalin A. Apparently, the prokaryotic endosymbiotes somehow alter the quantity of saccharide ligands in the C. oncopelti surface membrane.
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