Image processing of the cell surface of Prevotella intermedia using three fixatives

Abstract

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-analyzer. The absence or presence of certain structures were confirmed by detection of high-frequency elements of the power spectrum after Fourier transform. The width of each aspect of the 25,611 strain cell envelope was 15.3nm for the cell membrane, 7.2nm for the inner leaflet, 4.8nm for the outer leaflet, 3.3nm between the inner and the outer leaflets, and 12.4nm for the outer membrane. The widths for the 5 aspects of the 25, 611 strain were 9.8, 5.5, 2.6, 1.7 and 9.4nm by KR fixation, and 13.3, 5.5, 6.1, 1.7 and 7.7nm by FS fixation. High-frequency elements of the power spectrum after Fourier transform were detected in the peptidoglycan layer in transmission electron micrographs, and in particles on the cell surface in scanning electron micrographs. We found that the image processing system could be used to measure aspects of the bacterial cell envelope.