Confocal scanning light microscopy of the Escherichia coli nucleoid: comparison with phase-contrast and electron microscope images.
The nucleoid of living and OsO4- or glutaraldehyde-fixed cells of Escherichia coli strains was studied with a phase-contrast microscope, a confocal scanning light microscope, and an electron microscope. The trustworthiness of the images obtained with the confocal scanning light microscope was investigated by comparison with phase-contrast micrographs and reconstructions based on serially sectioned material of DNA-containing and DNA-less cells. This comparison showed higher resolution of the confocal scanning light microscope as compared with the phase-contrast microscope, and agreement with results obtained with the electron microscope. The effects of fixation on the structure of the nucleoid were studied in E. coli B/r H266. Confocal scanning light micrographs and electron microscopic reconstructions showed that the shape of the nucleoid remained similar after OsO4 or glutaraldehyde fixation; however, the OsO4 nucleoid appeared to be somewhat smaller and more centralized within the cell.
D002467:Cell Nucleus / Q000648:ultrastructure*; D004269:DNA, Bacterial / Q000032:analysis; D004926:Escherichia coli / Q000648:ultrastructure*; D005976:Glutaral / Q000494:pharmacology; D008854:Microscopy, Electron; D008858:Microscopy, Phase-Contrast; D009993:Osmium Tetroxide / Q000494:pharmacology
D004269:DNA, Bacterial; D009993:Osmium Tetroxide; D005976:Glutaral