[Three-dimensional reconstruction of mitotic cells of Cryptococcus neoformans based on serial section electron...

Ultra-thin serial sections of mitotic cells of Cryptococcus neoformans were observed by transmission electron microscope and computer-aided reconstruction of three-dimensional models were performed to understand the kinetics of the nucleus and mitochondria during mitosis. The separation of chromosomes occured in the protrusion of the nucleus extending in the bud (=daughter cell), followed by one set of chromosomes being moved back into the mother cell. These findings were similar to those reported in the heterobasidiomycetous yeasts. No giant mitochondrion, composed of a coalescence of all the mitochondria, was found. Volumetric analysis revealed the fluctuations in the mitochondrial volume: total cytoplasmic volume ratio were minimum during mitosis. In addition, methods, usefulness and limitations of observation of ultra-thin serial sections for understanding the morphology of cells and intracellular organelles were reviewed.