Regulation of Intracellular pH and Plasma Membrane Potential in Trypanosoma Cruzi and Trypanosoma Brucei

183 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2000.Regulation of intracellular pH (pHi) and the plasma membrane potential (DeltaPsi) was investigate in all stages of the pathogenic protozoans, T. cruzi and T. brucei utilizing the pH sensitive fluorescent dye BCECF and the potentiometric fluorescent dye bisoxonol. pH i in T. cruzi was found to be regulated primarily by a H+-ATPase with support from a Cl- conductive channel in all stages and an inwardly directed K+ channel in the mammalian stages. The DeltaPsi in T. cruzi was found to be generated by a H+-ATPase in all stages however there were significant differences in its regulation between the different stages. The trypomastigote (mammalian bloodstream) stage was found to be highly conductive to cations and there was a significant contribution to its DeltaPsi from a ouabain sensitive Na+/K+-ATPase. The epimastigote or insect stage was found to have a low conductance for cations and a minor contribution from the Na+/K+-ATPase. There was no evidence for cation conductance or a Na+/K+-ATPase in the intracellular mammalian amastigote stage. pHi in T. brucei procyclic or insect stages was found to be regulated primarily by a H+-ATPase with support from a Cl- conductive channel. In the mammalian bloodstream trypomastigote for pH i was regulated by a pyruvate-proton symport with a minor contribution from a H+-ATPase and supported by a Cl- conductive channel. The DeltaPsi of both procyclic and bloodstream forms was generated by a H+-ATPase. The bloodstream stage was found to be highly conductive to cations and there was a significant contribution to its DeltaPsi from a ouabain sensitive Na+/K+ -ATPase. The procyclic or insect stage was found to have a low conductance for cations and a minor contribution from the Na+/K +-ATPase.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD