Morphologic Analysis of the Apicoplast Formation in Plasmodium falciparum.

Author(s)

Marleen Linzke

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2020-01-24

Examining board members

Carsten Wrenger; Leticia Veras Costa Lotufo; Martina Schmidt; Gerhard Wunderlich

• Advisor: Carsten Wrenger

Abstract

Malaria, caused by Plasmodium spp., remains with more than 400.000 deaths per year one of the most severe diseases worldwide. Increasing drug resistance against the available antimalarial drugs poses a great threat in combating and eradication of this disease and new drug targets are greatly needed. The apicoplast, a chloroplast-like organelles of the Plasmodium parasite has been shown to be essential for the parasite survival and offers new drug target to exploit. How the parasite distributes this essential organelle during the asexual replication has been an open question up to this point. The ancestor of apicoplast, namely chloroplast and bacteria accomplish their distribution by the aid of proteins from the Min family which have not been identified in Plasmodium spp. yet. Through intensive BLAST research, one possible orthologue of one member of the Min family, MinD, was identified for P. falciparum. The orthologue displays the characteristic domains for the function of a ATPase described for MinD and is predicted to be targeted to the apicoplast of the parasite. Analysis of the recombinant protein demonstrated its ability to bind to the substrate ATP and polymerises upon addition of the substrate. This effect is dependent and enhanced by addition of divalent metals. Localisation studies in P. falciparum demonstrated the targeting to the apicoplast. Furthermore, overexpression of the orthologue in transgenic parasite lines displayed an inhibitory effect on the proliferation of the parasite. With the help of a reference line for visualisation of the apicoplast, techniques to visualise and analyse the apicoplast by live cell fluorescence imaging during the erythrocytic stage have been established and verified for the analysis of the apicoplast morphology under influence of the possible MinD orthologue. (AU)

• FAPESP's process: 14/23330-9 - Morphologic Analysis of the Apicoplast Formation in Plasmodium falciparum
• Grantee: Marleen Linzke
• Support Opportunities: Scholarships in Brazil - Doctorate