Structome analysis of yeast by electron microscopy

Abstract

Ultrastructure of cells has been examined by many studies including electron microscopy, leading to an impression that full knowledge about the cell has already been attained. However, quantitative and three-dimensional information are still lacking; the number of ribosomes per cell and numbers and cellular distribution of endoplasmic reticulum are not yet known. I have introduced a new concept “structome”, coined from the combination of structure and -ome, and defined as “information on the quantitative and three-dimensional structure of whole cells at electron microscopic level.” In the present study, structome analysis has been undertaken in yeast Exophiala dermatitidis using freezesubstitution and serial ultrathin sectioning. It was found that there were ~200,000 ribosomes in a cell;17-52 mitochondria in a cell and occupied ~10 % of the cell volume; and 5 - 10 endoplasmic reticula and occupied only ~ 0.2 % of the cell volume.