title: Electron probe analysis, X-ray mapping, and electron energy-loss spectroscopy of calcium, magnesium, and monovalent ions in log-phase and in dividing Escherichia coli B cells.
abstract: The elemental composition of individual cells of rapidly frozen and cryosectioned Escherichia coli B was measured with electron optical microanalytic methods. The Ca content was high (26.2 mmol/kg) in a 10-nm-wide region of the cell envelope. Amounts of cytoplasmic Ca in actively dividing cells were significantly higher (32.6 mmol/kg [dry weight]) than in the log-phase (1.5 mmol/kg) cells. Cellular Mg was 205 mmol/kg (dry weight) and it was uniformly distributed throughout the cell. Cells washed in distilled water before freezing lost monovalent ions (Na, Cl, and K), but the membrane-bound Ca and cellular Mg were not reduced, indicating that cellular Mg and membrane Ca are more tightly bound.
mesh_terms: D002118:Calcium / Q000032:analysis*; D002455:Cell Division; D002462:Cell Membrane / Q000032:analysis; D002713:Chlorine / Q000032:analysis; D003593:Cytoplasm / Q000032:analysis; D004577:Electron Probe Microanalysis / Q000379:methods; D004926:Escherichia coli / Q000032:analysis*; D008274:Magnesium / Q000032:analysis*; D010758:Phosphorus / Q000032:analysis; D011188:Potassium / Q000032:analysis; D012964:Sodium / Q000032:analysis; D013455:Sulfur / Q000032:analysis
chemical_list: D010758:Phosphorus; D002713:Chlorine; D013455:Sulfur; D012964:Sodium; D008274:Magnesium; D011188:Potassium; D002118:Calcium