Abstract:
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Transmission of malaria parasites from humans to mosquito
vectors requires that some asexual parasites differentiate into
sexual forms termed gametocytes. The balance between
proliferation in the same host and conversion into transmission
forms can be altered by the conditions of the environment. The
ability to accurately measure the rate of sexual conversion
under different conditions is essential for research addressing
the mechanisms underlying sexual conversion, and to assess the
impact of environmental factors. Here we describe new Plasmodium
falciparum transgenic lines with genome-integrated constructs in
which a fluorescent reporter is expressed under the control of
the promoter of the gexp02 gene. Using these parasite lines, we
developed a sexual conversion assay that shortens considerably
the time needed for an accurate determination of sexual
conversion rates, and dispenses the need to add chemicals to
inhibit parasite replication. Furthermore, we demonstrate that
gexp02 is expressed specifically in sexual parasites, with
expression starting as early as the sexual ring stage, which
makes it a candidate marker for circulating sexual rings in
epidemiological studies. |