A Plasmodium falciparum screening assay for anti-gametocyte drugs based on parasite lactate dehydrogenase detection

Abstract

The gametocyte pLDH assay is fast, easy to perform, cheap and reproducible and is suitable for screening novel transmission-blocking compounds, which does not require parasite transgenic lines.

In vitro inhibition of Plasmodium falciparum early and late stage gametocyte viability by extracts from eight traditionally used South African plant species

“…that are structurally similar to those known to be gametocytocidal either in vitro, in vivo or ex vivo Adjalley et al, 2011;D'Alessandro et al, 2013;Duffy and Avery, 2013;Jones et al, 1994;Lucantoni et al, 2013Lucantoni et al, , 2010Saenz et al, 2013;Sun et al, 2013;Yerbanga et al, 2014). Using these two parallel selection strategies, the ethnobotanical set was narrowed down to a hundred plant species from which eight were collected and screened in the current study.…”

“…Dried crude acetone extracts were dissolved in DMSO as stock solutions and diluted in culture medium prior to their use in assays (highest concentration of DMSO to which parasites were exposed to was 0.4% (v/v) which is non-toxic to gametocytes (D'Alessandro et al, 2015(D'Alessandro et al, , 2013Duffy and Avery, 2013;Lucantoni et al, 2013). These extracts were transferred into 96 well sterile plates and seeded with an equal volume (100 µl/well) of gametocyte suspension (0.8-3% gametocytaemia) to achieve a final haematocrit of 1% et al, 2013).…”

“…Plates were incubated at 37ºC for 72 hours, followed by the replacement of spent medium with extract-free culture medium (75% medium change) (D'Alessandro et al, 2015(D'Alessandro et al, , 2013.…”

Effect of Fluorescent Dyes on In Vitro -Differentiated, Late-Stage Plasmodium falciparum Gametocytes

“…We identified five synthetic dyes with good gametocytocidal activity. These five dyes, particularly the three mitochondrial dyes MitoRed, DiOC6, and rhodamine B, were more active than methylene blue, a drug with known gametocytocidal activity (15,(23)(24)(25). The cytotoxic concentration of the mitochondrial dyes was higher than 2.5 M when evaluated against HeLa cells in our previous study (22).…”

“…We revived this idea in a previous study by testing a panel of synthetic dyes for their in vitro activity against asexual stages and identified several compounds with high levels of in vitro activity (22). Methylene blue is known to show gametocytocidal activity (15,(23)(24)(25); therefore, we evaluated the activity of eight other antimalarial dyes against P. falciparum stage V gametocytes derived from the laboratory strain 3D7 and three clinical isolates from Lambaréné, Gabon, with an established bioluminescence assay (8).…”