A lattice structure in beef heart mitochondria induced by phosphotungstic acid

Ordered arrays of structured material were visualized in the intracristal space of isolated beef heart mitochondria in two ways. Under standard conditions of fixation, structured material in the intracristal space appeared as paracrystalline arrays nestled between two apposing membranes. When mitochondria were preincubated with phosphotungstic acid (PTA) prior to fixation, the structures in the mitochondrial intracristal space took on an open lattice structure. Such structures, either paracrystalline or lattice, could not be demonstrated in the mitochondrial matrix space under these conditions.