Bohne, Wolfgang

[["dc.bibliographiccitation.firstpage","835"],["dc.bibliographiccitation.issue","8"],["dc.bibliographiccitation.journal","International Journal for Parasitology"],["dc.bibliographiccitation.lastpage","841"],["dc.bibliographiccitation.volume","41"],["dc.contributor.author","Lin, San San"],["dc.contributor.author","Blume, Martin"],["dc.contributor.author","von Ahsen, Nicolas"],["dc.contributor.author","Gross, Uwe"],["dc.contributor.author","Bohne, Wolfgang"],["dc.date.accessioned","2018-11-07T08:54:48Z"],["dc.date.available","2018-11-07T08:54:48Z"],["dc.date.issued","2011"],["dc.description.abstract","Apicomplexan parasites undergo metabolic shifts in adaptation to environmental changes. Here, we investigate the metabolic requirements which are responsible for ATP homeostasis in the extracellular stage of Toxoplasma gondii. Surprisingly, we found that freshly released tachyzoites are able to maintain a constant ATP level during the first hour of extracellular incubation without the acquisition of external carbon sources. We further demonstrated that the extent of gliding motility and that of host cell invasion is independent from the availability of external carbon sources during this one hour extracellular period. The ATP level and the invasion efficiency of extracellular parasites were severely decreased by treatment with the glycolysis inhibitor, 2-deoxy-D-glucose, but not by the F(0)F(1)-ATPase inhibitor, oligomycin. This suggests that although the uptake of glucose itself is not required during the 1 h incubation period, extracellular parasites depend on the activity of the glycolytic pathway for ATP homeostasis. Furthermore, active glycolysis was evident by the secretion of lactate into the culture medium, even in the absence of external carbon sources. Together, our studies suggest that tachyzoites are independent from external carbon sources within the first hour of their extracellular life, which is the most relevant time span for finding a new host cell, but rely on the glycolytic metabolisation of internal carbon sources for ATP maintenance, gliding motility and host cell invasion. (C) 2011 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved."],["dc.identifier.doi","10.1016/j.ijpara.2011.03.005"],["dc.identifier.isi","000292234700004"],["dc.identifier.pmid","21515276"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/22753"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Sci Ltd"],["dc.relation.issn","0020-7519"],["dc.title","Extracellular Toxoplasma gondii tachyzoites do not require carbon source uptake for ATP maintenance, gliding motility and invasion in the first hour of their extracellular life"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","209"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Molecular Microbiology"],["dc.bibliographiccitation.lastpage","221"],["dc.bibliographiccitation.volume","82"],["dc.contributor.author","Lin, San San"],["dc.contributor.author","Gross, Uwe"],["dc.contributor.author","Bohne, Wolfgang"],["dc.date.accessioned","2018-11-07T08:51:20Z"],["dc.date.available","2018-11-07T08:51:20Z"],["dc.date.issued","2011"],["dc.description.abstract","In many apicomplexan parasites the entry of electrons from NADH into the electron transport chain is governed by type II NADH dehydrogenases (NDH2s) instead of a canonical complex I. Toxoplasma gondii expresses two NDH2 isoforms, TgNDH2-I and TgNDH2-II with no indication for stage-specific regulation. We dissected the orientation of both isoforms by using a split GFP assay and a protease protection assay after selective membrane permeabilization. The two approaches revealed that both TgNDH2 isoforms are internal enzymes facing with their active sites to the mitochondrial matrix. Single knockout mutants displayed a decreased replication rate and a reduced mitochondrial membrane potential, which were both more severe in the Tgndh2-II-deleted than in the Tgndh2-I-deleted mutant. Complementation with a myc-tagged, ectopic copy of the deleted gene restored the growth rate and the mitochondrial membrane potential. However, an overexpression of the remaining intact isoform could not restore the phenotype, suggesting that the two TgNDH2 isoforms are non-redundant and possess functional differences. Together, our studies indicate that although TgNDH2-I and TgNDH2-II are individually non-essential, the expression of both internal isoforms is required to maintain the mitochondrial physiology in T. gondii tachyzoites."],["dc.identifier.doi","10.1111/j.1365-2958.2011.07807.x"],["dc.identifier.isi","000295226700016"],["dc.identifier.pmid","21854467"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/21911"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell"],["dc.relation.issn","0950-382X"],["dc.title","Two internal type II NADH dehydrogenases of Toxoplasma gondii are both required for optimal tachyzoite growth"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1455"],["dc.bibliographiccitation.issue","11"],["dc.bibliographiccitation.journal","Biochimica et Biophysica Acta (BBA) - Bioenergetics"],["dc.bibliographiccitation.lastpage","1462"],["dc.bibliographiccitation.volume","1777"],["dc.contributor.author","Lin, San San"],["dc.contributor.author","Kerscher, Stefan"],["dc.contributor.author","Saleh, Ahmad"],["dc.contributor.author","Brandt, Ulrich"],["dc.contributor.author","Gross, Uwe"],["dc.contributor.author","Bohne, Wolfgang"],["dc.date.accessioned","2018-11-07T11:09:18Z"],["dc.date.available","2018-11-07T11:09:18Z"],["dc.date.issued","2008"],["dc.description.abstract","The apicomplexan parasite Toxoplasma gondii does not possess complex I of the mitochondrial respiratory chain, but has two genes encoding rotenone-insensitive, non-proton pumping type-II NADH dehydrogenases (NDH2s). The absence of such \"alternative\" NADH dehydrogenases in the human host defines these enzymes as potential drug targets. TgNDH2-I and TgNDH2-II are constitutively expressed in tachyzoites and bradyzoites and are localized to the mitochondrion as shown by epitope tagging. Functional expression of TgNDH2-I in the yeast Yarrowia lipolytica as an internal enzyme, with the active site facing the mitochondrial matrix, permitted growth in the presence of the complex I inhibitor DQA. Bisubstrate kinetics of TgNDH2-I measured within Y. lipolytica mitochondrial membrane preparations were in accordance with a ping-pong Using inhibition kinetics we demonstrate here that 1-hydroxy-2-alkyl-4(1)quinolones with long mechanism. alkyl chains of C(12) (HDQ) and C(14) are high affinity inhibitors for TgNDH2-I, while compounds with shorter side chains (C(5) and C(6)) displayed significantly higher IC(50) values. The efficiency of the various quinolone derivatives to inhibit TgNDH2-I enzyme activity mirrors their inhibitory potency in vivo, suggesting that a long acyl site chain is critical for the inhibitory potential of these compounds. (C) 2008 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.bbabio.2008.08.006"],["dc.identifier.isi","000261080200008"],["dc.identifier.pmid","18786503"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/52976"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.relation.issn","0005-2728"],["dc.title","The Toxoplasma gondii type-II NADH dehydrogenase TgNDH2-I is inhibited by 1-hydroxy-2-alkyl-4(1H)quinolones"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.journal","The FASEB Journal"],["dc.bibliographiccitation.volume","23"],["dc.contributor.author","Lin, San San"],["dc.contributor.author","Kerscher, Stefan"],["dc.contributor.author","Bohne, Wolfgang"],["dc.date.accessioned","2018-11-07T08:31:05Z"],["dc.date.available","2018-11-07T08:31:05Z"],["dc.date.issued","2009"],["dc.identifier.isi","000208621504218"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/17039"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Federation Amer Soc Exp Biol"],["dc.publisher.place","Bethesda"],["dc.relation.issn","0892-6638"],["dc.title","Biochemical Characterization of Toxoplasma gondii Mitochondrial Type II NADH Dehydrogenase Isoform I as a potential Drug Target"],["dc.type","conference_abstract"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","877"],["dc.bibliographiccitation.issue","6"],["dc.bibliographiccitation.journal","Eukaryotic Cell"],["dc.bibliographiccitation.lastpage","887"],["dc.bibliographiccitation.volume","8"],["dc.contributor.author","Lin, San San"],["dc.contributor.author","Gross, Uwe"],["dc.contributor.author","Bohne, Wolfgang"],["dc.date.accessioned","2018-11-07T08:29:07Z"],["dc.date.available","2018-11-07T08:29:07Z"],["dc.date.issued","2009"],["dc.description.abstract","The apicomplexan parasite Toxoplasma gondii expresses type II NADH dehydrogenases (NDH2s) instead of canonical complex I at the inner mitochondrial membrane. These non-proton-pumping enzymes are considered to be promising drug targets due to their absence in mammalian cells. We recently showed by inhibition kinetics that T. gondii NDH2-I is a target of the quinolone-like compound 1-hydroxy-2-dodecyl-4(1H)quinolone (HDQ), which inhibits T. gondii replication in the nanomolar range. In this study, the cationic fluorescent probes Mitotracker and DiOC(6)(3) (3,3'-dihexyloxacarbocyanine iodine) were used to monitor the influence of HDQ on the mitochondrial inner membrane potential (Delta Psi m) in T. gondii. Real-time imaging revealed that nanomolar HDQ concentrations led to a Delta Psi m collapse within minutes, which is followed by severe ATP depletions of 30% after 1 h and 70% after 24 h. Delta Psi m depolarization was attenuated when substrates for other dehydrogenases that can donate electrons to ubiquinone were added to digitonin-permeabilized cells or when infected cultures were treated with the F(o)-ATPase inhibitor oligomycin. A prolonged treatment with sublethal concentrations of HDQ induced differentiation into bradyzoites. This dormant stage is likely to be less dependent on the Delta Psi m, since Delta Psi m-positive parasites were found at a significantly lower frequency in alkaline-pH-induced bradyzoites than in tachyzoites. Together, our studies reveal that oxidative phosphorylation is essential for maintaining the ATP level in the fast-growing tachyzoite stage and that HDQ interferes with this pathway by inhibiting the electron transport chain at the level of ubiquinone reduction."],["dc.identifier.doi","10.1128/EC.00381-08"],["dc.identifier.isi","000266640100008"],["dc.identifier.pmid","19286986"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/16572"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Soc Microbiology"],["dc.relation.issn","1535-9778"],["dc.title","Type II NADH Dehydrogenase Inhibitor 1-Hydroxy-2-Dodecyl-4(1H) Quinolone Leads to Collapse of Mitochondrial Inner-Membrane Potential and ATP Depletion in Toxoplasma gondii"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]