Lidya B. Sánchez

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Giardia intestinalis (syn. lamblia) is one of the most widespread intestinal protozoan pathogens worldwide, causing hundreds of thousands of cases of diarrhoea each year. Giardia is a member of the diplomonads, often described as an ancient protist group whose primitive nature is suggested by the lack of typical eukaryotic organelles (for example,(More)
Differentiation of trophozoites into cysts in Entamoeba species has been described morphologically and to a lesser extent biochemically, but studies of stage specific gene expression have not been reported. At present Entamoeba invadens is the only species that can be induced to differentiate in axenic culture and is a useful model system for the human(More)
The gene coding for the acetyl-CoA synthetase (ADP-forming) from the amitochondriate eukaryote Giardia lamblia has been expressed in Escherichia coli. The recombinant enzyme exhibited the same substrate specificity as the native enzyme, utilizing acetyl-CoA and adenine nucleotides as preferred substrates and less efficiently, propionyl- and succinyl-CoA. N-(More)
Pyridoxal-5'-phosphate-dependent cysteine desulfurase (IscS) is an essential enzyme in the assembly of FeS clusters in bacteria as well as in the mitochondria of eukaryotes. Although FeS proteins are particularly important for the energy metabolism of amitochondrial anaerobic eukaryotes, there is no information about FeS cluster formation in these(More)
Nuclear-coded valyl-tRNA synthetase (ValRS) of eukaryotes is regarded of mitochondrial origin. Complete ValRS sequences obtained by us from two amitochondriate protists, the diplomonad, Giardia lamblia and the parabasalid, Trichomonas vaginalis were of the eukaryotic type, strongly suggesting an identical history of ValRS in all eukaryotes studied so far.(More)
The so far unelucidated pathway of formation of ethanol, one of the major end products of the fermentative metabolism of the amitochondriate protist, Giardia lamblia, was examined. Two NAD-dependent enzymatic activities, an acetaldehyde dehydrogenase (CoA-acetylating) (EC 1.2.1.10) and an alcohol dehydrogenase (EC 1.1.1.1) were detected. These are assumed(More)
Glucokinase (GK) and glucosephosphate isomerase (GPI), the first two enzymes of the glycolytic pathway of the diplomonads Giardia intestinalis and Spironucleus barkhanus, Type I amitochondriate eukaryotes, were sequenced. GPI of the parabasalid Trichomonas vaginalis was also sequenced. The diplomonad GKs belong to a family of specific GKs present in(More)
Genes encoding putative mitochondrial-type heat shock protein 70 (mit-hsp70) were isolated and sequenced from amitochondriate protists, Giardia intestinalis, Entamoeba histolytica, and two microsporidians, Encephalitozoon hellem and Glugea plecoglossi. The deduced mit-hsp70 sequences were analyzed by sequence alignments and phylogenetic reconstructions. The(More)
Giardia lamblia, an amitochondriate eukaryote, contains acetyl-CoA synthetase (ADP-forming), an enzyme known only from one other eukaryote (Entamoeba histolytica) and a few anaerobic prokaryotes. The enzyme has been purified about 350-fold. The activity in the direction of acetate formation was dependent on ADP and inorganic phosphate. The reverse reaction(More)
Sequences of putative fructose-1,6-bisphospate aldolases (FBA) in five amitochondriate unicellular eukaryotes, the diplomonads Giardia intestinalis (published earlier) and Spironucleus barkhanus, the pelobiont Mastigamoeba balamuthi,the entamoebid Entamoeba histolytica, and the parabasalid Trichomonas vaginalis all belong to Class II of FBAs and are highly(More)