Pyruvate-converting activity in the spores of the microsporidian genus Paranosema (Antonospora).

Microsporidia, a large group of fungi-related protozoa with an obligate intracellular lifestyle, are characterized by a drastically reduced cell machinery and a unique metabolism. These parasites possess genes encoding glycolysis components and glycerol-phosphate shuttle, but lack typical mitochondria, Krebs cycle, respiratory chain and pyruvate-converting enzymes, except for two subunits of the E(1) enzyme of the pyruvate dehydrogenase complex. This study demonstrates that in spite of the above, destroyed spores of the microsporidian Paranosema (Antonospora) grylli and P. locustae deplete pyruvate content in the incubation medium. This activity is sensitive to heat, proportionally distributed between the soluble and the insoluble fractions and does not depend on additional ions or cofactors.