A study of cell fusion and possible genetic recombination in the parasitic protozoan Leishmania

Abstract

Microspectrophotometric quantitative DNA measurements were made on cells of the promastigote stage and the amastigote stage of species in the genus "Leishmania," for the purpose of determining the period of the life cycle where a ploidy change may occur.

The results of this study indicate that cellular fusion occurs during the amastigote stage in the genus "Leishmania." These may subsequently undergo mitotic division, while the promastigotes exhibited an accelerated growth stage followed by mitosis, but no cell fusion. Mitosis and cell fusion are the amastigotes occurs within the macrophage cell. Results also indicate that cell fusion increases with the duration of infection in the macrophages. Cell fusion, rather than a single cell doubling its own DNA, is confirmed in isozyme data from what appears to be hybrid isolates of "L. panamensis" and "L. braziliensis." Cell fusion in the amastigote presents a possible mechanism for genetic exchange.