Total RNA was prepared by lysing cultured entamoebas and giardias in a guanidinium isothiocyanate solution and by centrifuging the lysate through a cesium chloride gradient (Choczynski and Sacchi, 1987).
vaginalis Fe-hydrogenase was greater than that of the recombinant entamoebic GST-entamoebic Fe-hydrogenase and was inhibited by a lysate of non-transfected entamoebas (Table 1).
Cultured entamoebas and giardias express mRNAs encoding short Fe-hydrogenases.
The entamoebic Fe-hydrogenase 2 was much more similar (>38% amino acid identities) to predicted long Fe-hydrogenases of Bacteroides fragilis and Treponema denticola than to short Fe-hydrogenases of entamoebas, giardias, trichomonads, and other anaerobic bacteria (<28% amino acid identities; Fig.
This lateral gene transfer would not have occurred recently, because the Fe-hydrogenases of entamoebas and giardias showed only a 40% amino acid identity with each other, and each fe-hydrogenase gene has the codon usage of its host.
This is also the first time that an fe-hydrogenase gene (encoding the long hydrogenase of entamoebas) has been inferred to have been laterally transferred from a bacterium, although numerous genes encoding fermentation enzymes (e.g., alcohol dehydrogenases, malic enzyme, and acetyl-CoA synthases) appear to have been laterally transferred from prokaryotes to amoebas and giardias (Rosenthal et al., 1997; Field et at., 2000; Nixon et aL, 2002).
Parasito N % IC95% Endolimax nana 28 6,5 4,4 - 9,4 Entamoeba
coli 27 6,3 4,2 - 9,1 Giardia intestinalis 15 3,5 2,0 - 5,8 Ascaris lumbricoides 6 1,4 0,6 - 3,2 Strongyloides stercoralis 3 0,7 0,2 - 2,2 Enterobius vermicularis 3 0,7 0,2 - 2,2 Ancilostomideo 1 0,2 0,0 - 1,5 Entamoeba
hystolitica 1 0,2 0,0 - 1,5 Taenia sp 1 0,2 0,0 - 1,5 Total de exames positivos 69 16,0 12,7 - 19,9 Tabela 2.