. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. NIXON ET AL Table 1 Activities / Entamoeba histolytica anil Trichomonas \aginalix Fe-hydrogencutes Sample Hydrogenase activity (nmol/min/mg of protein)'' Bacteria transformed with E. histolyticti Fe-hydrogenase Transfected E. hixiolytica with Fe- hydrogenase I ru humnmis Yu^nidlis T. viif>inalis + mg E. histolyticti lysate" 36(2) ± (3) 167 ± 32 (41 114(2) a Averages +/— standard deviations, where possible. Number of deter- minations in parentheses. '"Calculated A", = mg (amount of E. lii\i
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. NIXON ET AL Table 1 Activities / Entamoeba histolytica anil Trichomonas \aginalix Fe-hydrogencutes Sample Hydrogenase activity (nmol/min/mg of protein)'' Bacteria transformed with E. histolyticti Fe-hydrogenase Transfected E. hixiolytica with Fe- hydrogenase I ru humnmis Yu^nidlis T. viif>inalis + mg E. histolyticti lysate" 36(2) ± (3) 167 ± 32 (41 114(2) a Averages +/— standard deviations, where possible. Number of deter- minations in parentheses. '"Calculated A", = mg (amount of E. lii\in/yhm Usate in mg of protein to cause 50% reduction of 7". ;im///.v hydrogenase activity). 1 2 3 SOObp. the T. 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). This may explain why it was difficult to detect Fe-hydrogenase activity in lysates of nontransfected ent- amoebas, even though Fe-hydrogenase 1 mRNAs were identified from them by RT-PCR (next section). Cultured entamoehas and giurdiiifi exprexx mRNAs en- coding short Fe-hydrogenases. We isolated an fe-hydroge- nase gene of G. lanihlia. because we have frequently com- pared the fermentation enzymes of this diplomonad with those of E. hixtolytieu (Rosenthal et 1997; Field et ul., 2000; Nixon et ul., 2002). A search of the contigs predicted from the G. lamblia shogun sequences suggested that this gene, which predicts a short Fe-hydrogenase. is the only hydrogenase gene present within the giardial genome. Like the entamoebic Fe-hydrogenase 1. the predicted giardial Fe-hydrogenase lacked an N-terminal organelle-targeting sequence and had two ferredoxin-like iron-sulfur centers and a hydrogenase iron-sulfur center like those present in the short Fe-hydrogenases of T. vugimilis, Desulfovibrio sp., and Clostridiu sp. iCammark. 1992; Thompson et ai, 1994; Bui and Johnson. 1496; Homer e
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
