The "primitive" microaerophile Giardia intestinalis (syn. lamblia, duodenalis) has specialized membranes with electron transport and membrane-potential-generating functions.
Here it is shown that the flagellated protozoon Giardia intestinalis, commonly regarded as an early branching eukaryote because of its lack of mitochondria, has membraneous structures that partition the cationic, membrane-potential-sensitive fluorophore rhodamine 123. This organism also reduces a tetrazolium fluorogen at discrete plasma-membrane-associated sites. That these functions occur in distinctive specialized membrane systems supports the growing evidence that G. intestinalis may not be primitive, but is derived from an aerobic, mitochondria-containing flagellate.
Lloyd
David
D
School of Biosciences (Microbiology), Cardiff University, PO Box 915, Cardiff CF10 3TL, Wales, UK1.
Harris
Janine C
JC
School of Biosciences (Microbiology), Cardiff University, PO Box 915, Cardiff CF10 3TL, Wales, UK1.
Maroulis
Sarah
S
Department of Biochemistry and Molecular Genetics2 and Cellular Analysis Facility, Department of Microbiology and Immunology3, University of New South Wales, Sydney 2052, Australia.
Wadley
Ron
R
Department of Biochemistry and Molecular Genetics2 and Cellular Analysis Facility, Department of Microbiology and Immunology3, University of New South Wales, Sydney 2052, Australia.
Ralphs
James R
JR
School of Biosciences (Microbiology), Cardiff University, PO Box 915, Cardiff CF10 3TL, Wales, UK1.
Hann
Ao C
AC
School of Biosciences (Microbiology), Cardiff University, PO Box 915, Cardiff CF10 3TL, Wales, UK1.
Turner
Michael P
MP
School of Biosciences (Microbiology), Cardiff University, PO Box 915, Cardiff CF10 3TL, Wales, UK1.
Edwards
Michael R
MR
Department of Biochemistry and Molecular Genetics2 and Cellular Analysis Facility, Department of Microbiology and Immunology3, University of New South Wales, Sydney 2052, Australia.
D000818:Animals; D004579:Electron Transport; D005456:Fluorescent Dyes / Q000378:metabolism; D005562:Formazans / Q000378:metabolism; D016829:Giardia lamblia / Q000166:cytology* / Q000254:growth & development / Q000378:metabolism*; D008564:Membrane Potentials; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000378:metabolism
D005456:Fluorescent Dyes; D005562:Formazans