<> "The repository administrator has not yet configured an RDF license."^^ . <> . . "EHD proteins in apicomplexan parasites"^^ . "A bottle neck in malaria research is the investigation of Plasmodium falciparum liver\r\nstage parasites because of technical issues in the infection of Anopheles mosquitoes\r\nwith these parasites and subsequent generation of infectious sporozoites. Therefore\r\nI, in close collaboration with a colleague, established a combined in vitro/in vivo P.\r\nfalciparum life-cycle in our lab. For that a protocol was established that included\r\nthe generation of sexual P. falciparum stages in cell culture that were subsequently\r\ntransmitted to Anopheles mosquitoes utilizing a special membrane feeding system.\r\nLater in the life-cycle sporozoites were extracted from the mosquito salivary glands\r\nto nally infect liver cells for further studies. We were able to establish a constant\r\nmosquito-infection rate for several months to perform experiments on P. falciparum\r\nsporozoites and exo-erythrocytic forms.\r\nTo help decipher the in apicomplexans so far mostly uncharacterized cellular process\r\nendocytosis I investigated the function and localization of an EH-domain containing\r\ndynamin-like protein in Toxoplasma and Plasmodium. It belongs to a family\r\nof eukaryotic Eps15-homology domain containing proteins (EHDs) that have been\r\ncharacterized in higher eukaryotes and especially vertebrates to be part of endocytic\r\nevents such as vesicular tracking and endocytic recycling. I was able to show by an\r\nin silico analysis that in contrast to vertebrates (four dierent EHDs) there is only\r\none protein member of this familiy existing in each apicomplexan. Nevertheless, the\r\napicomplexan EHD-protein has similar to all other EHD-proteins a predicted characteristic\r\nATPase-domain (dynamin-like G-domain) and the Eps15-homology domain\r\n(EH). Through a \r\nuorescent tagging approach I was able to show a dynamic localization\r\nof the Toxoplasma EHD-protein member TgRME-1 (named after its ortholog\r\nin C. elegans receptor-mediated endocytosis protein 1) within the parasites. It localized\r\nto a vesicular compartment within the parasites that did not colocalize with\r\nknown organelles so far. The compartment fragmented upon cellular division and is\r\nmost likely involved in vesicular tracking of supply vesicles that transport lipids or\r\nother nutrients to the newly forming daughter-cells. From the data obtained in this\r\nthesis it can be hypothesized that the TgRME-1 labelled compartment represents\r\na storage compartment that is filled up during the non-replicative phase and during\r\nendodyogeny helps to form daughter-cells. Structural analysis of the protein by\r\ndeletion of either the G-domain or the EH-domain revealed a similar architecture of\r\nthe protein compared to published data on mammalian EHDs. Investigation of the\r\nPlasmodium berghei EHD (PbEHD) with an antibody generated against the protein\r\nrevealed a dfferent localization in different parasite stages. Whereas the protein\r\nlocalized to several vesicular compartments in the sporozoite stage it concentrated\r\nto a single organelle-like compartment in liver-stages 24 hours after invasion. This\r\ncompartment later (48 hours after invasion) also fragmented and was distributed to\r\nthe newly forming merozoites during schizogony, similar to TgRME-1. This subcellular\r\nlocalization indicated that both proteins might share a similar function in\r\ntachyzoites of Toxoplasma and Plasmodium liver stage parasites. A phenotypical analysis of PbEHD via generation of a pbehd (-) parasite revealed a putative function\r\nfor the protein during intrahepatic development. The pbehd (-) liver stage parasite\r\nshowed a reduced growth rate in vivo and in vitro but was still able to complete\r\nthe life-cycle. In vivo, C57BL/6 mice infected with pbehd (-) parasites showed a\r\nprolonged prepatency period and did not develop experimental cerebral malaria in\r\ncontrast to wildtype-infected mice. I was able to narrow down this protective effect\r\nsolely to both the prolonged liver-stage phase and the involvement of the immunemodulator\r\ncytokine IL-10.\r\nEven though a defined role for the EHD-protein in the apicomplexan parasites could\r\nnot be determined in this thesis I was able to characterize its architecure and localization\r\nin Toxoplasma gondii and Plasmodium berghei. I was able to identify a so\r\nfar uncharacterized compartment in these parasites that is most likely involved in\r\nendocytic-recycling and storage of nutrients such as lipids for the parasites. In addition,\r\nmy studies showed that the apicomplexan EHD-protein is involved in processes\r\nof the cellular division. A better understanding of these and other mechanisms of\r\nendocytosis will lead to anti-parasitic strategies that may reduce the burden caused\r\nby apicomplexan parasites."^^ . "2012" . . . . . . . "Florian"^^ . "Kohlhepp"^^ . "Florian Kohlhepp"^^ . . . . . . "EHD proteins in apicomplexan parasites (PDF)"^^ . . . "PhD thesis F.Kohlhepp final.pdf"^^ . . . "EHD proteins in apicomplexan parasites (Other)"^^ . . . . . . "indexcodes.txt"^^ . . . "EHD proteins in apicomplexan parasites (Other)"^^ . . . . . . "lightbox.jpg"^^ . . . "EHD proteins in apicomplexan parasites (Other)"^^ . . . . . . "preview.jpg"^^ . . . "EHD proteins in apicomplexan parasites (Other)"^^ . . . . . . "medium.jpg"^^ . . . "EHD proteins in apicomplexan parasites (Other)"^^ . . . . . . "small.jpg"^^ . . "HTML Summary of #14297 \n\nEHD proteins in apicomplexan parasites\n\n" . "text/html" . . . "500 Naturwissenschaften und Mathematik"@de . "500 Natural sciences and mathematics"@en . . . "570 Biowissenschaften, Biologie"@de . "570 Life sciences"@en . . . "610 Medizin"@de . "610 Medical sciences Medicine"@en . .