ELECTRON MICROSCOPY OF ULTRA-THIN SECTIONS OF BACTERIA I

Open Access
Publisher Website
Google Scholar
Abstract
Electron micrographs of ultra-thin sections of osmium-fixed and methacrylate-embedded cells of B. cereus provide evidence for the following description of cell division (1) 4 or more spherical bodies approx. 0.2u in diam. and designated as peripheral bodies arrange themselves annularly on the cell surface at a point where the division of the nuclear material is to occur. (2) A ring of cell wall material is secreted centripetally. The peripheral bodies remain inside the inner edge of the forming cross wall and move inwards with it. (3) When the cross wall is complete and partitions the cell, it thickens and splits forming an independent transverse cell wall for each daughter cell. (4) The adjacent ends of the cells round off and the cells separate. If a cytoplasmic membrane exists it does not partition the cell independently of the cell wall. The location and appearance of the nuclear apparatus agrees with earlier observations. The lack of suitable criteria prevents the identification of either chromosomes or mitotic figures.