Linked Life Data

9813002

Source:http://linkedlifedata.com/resource/pubmed/id/9813002

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
47
pubmed:dateCreated
1998-12-21
pubmed:abstractText
Respiration, oxidative phosphorylation, and the mitochondrial membrane potential (DeltaPsi) of tachyzoites of the apicomplexan parasite Toxoplasma gondii were assayed in situ using very low concentrations of digitonin to render their plasma membrane permeable to succinate, ADP, safranin O, and other small molecules. The rate of basal respiration was slightly increased by digitonin when the cells were incubated in medium containing succinate. ADP promoted an oligomycin-sensitive transition from resting to phosphorylating respiration. Respiration was sensitive to antimycin A and cyanide, and N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) was oxidized by antimycin A-poisoned mitochondria. The addition of ADP after TMPD/ascorbate also resulted in phosphorylating respiration. The antitoxoplasmosis drug atovaquone, at a very low concentration (0.03 microM), totally inhibited respiration and disrupted the mitochondrial membrane potential. Atovaquone was shown to inhibit the respiratory chain of T. gondii and mammalian mitochondria between cytochrome b and c1 as occurs with antimycin A1. Phosphorylation of ADP could not be obtained in permeabilized tachyzoites in the presence of either pyruvate, 3-oxo-glutarate, glutamate, isocitrate, dihydroorotate, alpha-glycerophosphate, or endogenous substrates. Although ADP phosphorylation was detected in the presence of malate, this activity was rotenone-insensitive and was probably due to the conversion of malate into succinate through a fumarate reductase activity that was detected in mitochondrial extracts. Together these results provide the first direct biochemical evidence that the respiratory chain and oxidative phosphorylation are functional in apicomplexan parasites, although the terminal respiratory pathway is different from that in the mammalian host.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
20
pubmed:volume
273
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
31040-7
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Respiration and oxidative phosphorylation in the apicomplexan parasite Toxoplasma gondii.
pubmed:affiliation
Laboratory of Molecular Parasitology, Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't