1995 Volume 58 Issue 3 Pages 217-231
We measured the cell envelope structures of Prevotella intermedia ATCC 25611, ATCC 33563 and Porphyromonas gingivalis 381 after shade processing and threshold setting using the LUZEX-FS image processor. The periodical structure of the bacterial cell surface was studied to detect the high frequency element of the power spectrum after Fourier transform. The width of each aspect of the 25611 strain cell envelope by GA-OsO4 fixation was 13.0nm for the cell membrane, 4.6nm for the inner leaflet, 2.7nm between the inner and the outer leaflets, 3.6nm for the outer leaflet, 2.1nm for the periplasmic space near the cell membrane, 6.2nm for the peptidoglycan layer (PG), 17.2nm for the periplasmic space near the outer membrane, 9.2nm for the outer membrane, 2.7nm for the inner leaflet, 3.1nm between the inner and the outer leaflets, and 3.1nm for the outer leaflet. PG could not be observed in the sample fixed by freeze substitution (FS). The width of periplasmic space (between the outer leaflet of the cell membrane and the inner leaflet of the outer membrane) of bacteria by GA-OsO4 or Kellenberger-Ryter fixation was larger than that of bacteria by FS. The high-frequency element of the power spectrum after fast Fourier transform was detected in the periplasmic space in transmission electron micrographs, and in particles on the cell surface in scanning electron micrographs. Some twists in the image of the periplasmic space could be detected after inverse fast Fourier transform.
We found that the image processing system could be used to measure aspects and periodical structure of the bacterial cell envelope.
