Presence of intramitochondrial bodies in avian leukemic myeloblasts

Electron-dense bodies of about 50–100 nm in diameter were detected by electron microscopy in mitochondria of chick leukemic myeloblasts cultivated by the column technique. Ninety percent of these bodies were characterized by the dimension 50–80 nm without any typical internal structure, 10% of them with diameter of 80–100 nm revealed the structure of intracytoplasmic A particles. These isolated virus-like particles sedimenting at the density 1·28 g/cm 3 in sucrose gradient were analysed by electron microscopy using negative staining method. No intramitochondrial bodies were detected in mitochondria of leukemic myeloblasts cultivated in suspension culture in the same cultivation medium. The possible effect of differences in the metabolic state of the cells on the accumulation of intramitochondrial bodies were discussed.