@article{FellerThomKochetal.2013,
  author    = {Feller, Tatjana and Thom, Pascal and Koch, Natalie and Spiegel, Holger and Addai-Mensah, Otchere and Fischer, Rainer and Reimann, Andreas and Pradel, Gabriele and Fendel, Rolf and Schillberg, Stefan and Scheuermayer, Matthias and Schinkel, Helga},
  title     = {Plant-Based Production of Recombinant Plasmodium Surface Protein Pf38 and Evaluation of its Potential as a Vaccine Candidate},
  series = {PLOS ONE},
  volume    = {8},
  journal   = {PLOS ONE},
  number    = {11},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0079920},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-128221},
  pages     = {e79920},
  year      = {2013},
  abstract  = {Pf38 is a surface protein of the malarial parasite Plasmodium falciparum. In this study, we produced and purified recombinant Pf38 and a fusion protein composed of red fluorescent protein and Pf38 (RFP-Pf38) using a transient expression system in the plant Nicotiana benthamiana. To our knowledge, this is the first description of the production of recombinant Pf38. To verify the quality of the recombinant Pf38, plasma from semi-immune African donors was used to confirm specific binding to Pf38. ELISA measurements revealed that immune responses to Pf38 in this African subset were comparable to reactivities to AMA-1 and \(MSP1_{19}\). Pf38 and RFP-Pf38 were successfully used to immunise mice, although titres from these mice were low (on average 1:11.000 and 1:39.000, respectively). In immune fluorescence assays, the purified IgG fraction from the sera of immunised mice recognised Pf38 on the surface of schizonts, gametocytes, macrogametes and zygotes, but not sporozoites. Growth inhibition assays using \(\alpha Pf38\) antibodies demonstrated strong inhibition \((\geq 60 \\% ) \) of the growth of blood-stage P. falciparum. The development of zygotes was also effectively inhibited by \(\alpha Pf38\) antibodies, as determined by the zygote development assay. Collectively, these results suggest that Pf38 is an interesting candidate for the development of a malaria vaccine.},
  language  = {en}
}
@article{KernAgarwalHuberetal.2014,
  author    = {Kern, Selina and Agarwal, Shruti and Huber, Kilian and Gehring, Andre P. and Str{\"o}dke, Benjamin and Wirth, Christine C. and Br{\"u}gl, Thomas and Abodo, Liane Onambele and Dandekar, Thomas and Doerig, Christian and Fischer, Rainer and Tobin, Andrew B. and Alam, Mahmood M. and Bracher, Franz and Pradel, Gabriele},
  title     = {Inhibition of the SR Protein-Phosphorylating CLK Kinases of Plasmodium falciparum Impairs Blood Stage Replication and Malaria Transmission},
  series = {PLOS ONE},
  volume    = {9},
  journal   = {PLOS ONE},
  number    = {9},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0105732},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-115405},
  pages     = {e105732},
  year      = {2014},
  abstract  = {Cyclin-dependent kinase-like kinases (CLKs) are dual specificity protein kinases that phosphorylate Serine/Arginine-rich (SR) proteins involved in pre-mRNA processing. Four CLKs, termed PfCLK-1-4, can be identified in the human malaria parasite Plasmodium falciparum, which show homology with the yeast SR protein kinase Sky1p. The four PfCLKs are present in the nucleus and cytoplasm of the asexual blood stages and of gametocytes, sexual precursor cells crucial for malaria parasite transmission from humans to mosquitoes. We identified three plasmodial SR proteins, PfSRSF12, PfSFRS4 and PfSF-1, which are predominantly present in the nucleus of blood stage trophozoites, PfSRSF12 and PfSF-1 are further detectable in the nucleus of gametocytes. We found that recombinantly expressed SR proteins comprising the Arginine/Serine (RS)-rich domains were phosphorylated by the four PfCLKs in in vitro kinase assays, while a recombinant PfSF-1 peptide lacking the RS-rich domain was not phosphorylated. Since it was hitherto not possible to knock-out the pfclk genes by conventional gene disruption, we aimed at chemical knock-outs for phenotype analysis. We identified five human CLK inhibitors, belonging to the oxo-beta-carbolines and aminopyrimidines, as well as the antiseptic chlorhexidine as PfCLK-targeting compounds. The six inhibitors block P. falciparum blood stage replication in the low micromolar to nanomolar range by preventing the trophozoite-to-schizont transformation. In addition, the inhibitors impair gametocyte maturation and gametogenesis in in vitro assays. The combined data show that the four PfCLKs are involved in phosphorylation of SR proteins with essential functions for the blood and sexual stages of the malaria parasite, thus pointing to the kinases as promising targets for antimalarial and transmission blocking drugs.},
  language  = {en}
}