title: Cardiolipin, a lipid found in mitochondria, hydrogenosomes and bacteria was not detected in Giardia lamblia.
abstract: Giardia lamblia is a protozoan parasite with many characteristics common among eukaryotic cells, but lacking other features found in most eukaryotes. Cardiolipin is a phospholipid located exclusively in energy transducing membranes and it was identified in mitochondria, bacteria, hydrogenosomes and chloroplasts. In eukaryotes, cardiolipin is the only lipid that is synthesized in the mitochondria. Biochemical procedures (TLC, HPLC) and fluorescent tools (NAO) were applied in order to search for cardiolipin in G. lamblia. In addition, BLAST searches were used to find homologs of enzymes that participate in the cardiolipin synthesis. Cardiolipin synthase was searched in the Giardia genome, using Saccharomyces cerevisiae and Mycoplasma penetrans sequences as bait. However, a good match to G. lamblia related proteins was not found. Here we show that mitosomes of G. lamblia apparently do not contain cardiolipin, which raises the discussion for its endosymbiotic origin and for the previous proposal that Giardia mitosomes are modified mitochondria.
authors.affiliation: Universidade Santa Ursula, Laboratório de Ultraestrutura Celular, Rio de Janeiro, Botafogo, Brazil.
authors.forename: Ivone de Andrade
authors.initials: Ide A
authors.lastname: Rosa
authors.forename: Marcelo
authors.initials: M
authors.lastname: Einicker-Lamas
authors.forename: Robson Roney
authors.initials: RR
authors.lastname: Bernardo
authors.forename: Marlene
authors.initials: M
authors.lastname: Benchimol
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002308:Cardiolipins / Q000032:analysis* / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D017124:Conserved Sequence; D016829:Giardia lamblia / Q000737:chemistry* / Q000201:enzymology; D007455:Iodine; D008055:Lipids / Q000302:isolation & purification; D008565:Membrane Proteins / Q000032:analysis / Q000737:chemistry; D008928:Mitochondria / Q000737:chemistry*; D018661:Mycoplasma penetrans / Q000201:enzymology; D015388:Organelles / Q000737:chemistry / Q000201:enzymology; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D016415:Sequence Alignment; D017855:Transferases (Other Substituted Phosphate Groups) / Q000032:analysis / Q000737:chemistry
chemical_list: D002308:Cardiolipins; D008055:Lipids; D008565:Membrane Proteins; D007455:Iodine; D017855:Transferases (Other Substituted Phosphate Groups); C100091:cardiolipin synthetase; C020676:CDP-diacylglycerol-glycerol-3-phosphate 3-phosphatidyltransferase