Investigating the functions of remnant mitochondria of human parasitic protozoa. (360G-Wellcome-089803_C_09_A)

We will test the hypothesis that the essential role of microsporidian mitosomes is in cellular Fe/S protein biosynthesis, using subcellular fractionation to provide material for in vitro assays of organelle function, complemented by genetic and biochemical studies, and by quantitative immunolocalisation of key proteins at the electron microscope (EM) level. The ultrastructure of microsporidian mitosomes will be elucidated using sophisticated EM methods, to provide a detailed understanding of mi tosome biogenesis and inheritance during parasite division. The transport proteins used to support the metabolism and energy needs of microsporidian and Giardia mitosomes will be identified and functionally characterized to provide further insights into the functions of these organelles. The characterisation of microsporidian transport proteins that are expressed on the parasite surface will, in conjunction with genomic-based inferences of parasite metabolism, provide clues to parasite-host me tabolic inter-dependencies that may be essential for the growth and survival of these obligate intracellular parasites.