Morphological evidence for penetration of anti-O antibody through the capsule of Klebsiella pneumoniae

A total of 11 strains of Escherichia coli (E. coli) belonging to serogroup O157 were examined for the expression of long-chain lipopolysaccharide (LPS) and major outer-membrane proteins (OMPs) by means of SDS-PAGE. The strains belonged to either one of four different flagellar (H) types or did not express flagella. Four of the eleven strains carried genes encoding Shiga-like toxins (SLTs). All the strains exhibited one of four LPS profiles, designated A, B, C or D. Electron microscopic analysis with the freezesubstitution technique demonstrated the differences in the cell surface structures of strains with each LPS profile. Strains with LPS profile A, B or C had layers of thin fibers 10, 20 and 20 nm long, respectively, on the outer membrane but strains with LPS profile D had no such structure. An analysis of the OMPs showed that all the strains had one of four OMP profiles, designated I, II, III or W. Both LPS and OMP profiles were dependent on H-serotypes, and the combination pattern of LPS and OMP profiles of the strains was unique for each H-serotype. These data support the existence of heterogeneous groups of 0157 strains.

Section: Electron Microscopic Analysis Of Cell Surface Structures Of supporting

confidence: 88%

Heterogeneity in Expression of Lipopolysaccharide and Major Outer‐Membrane Proteins by Strains of Escherichia coli O157 with Different H‐Serotypyes

Fujimoto

Meno

Horikawa

1998

“…The inner one-fourth of the layer consisted of fibers arranged rectangularly on the surface of the cell wall, and we thus assumed that the antibody may not reach this layer. The experiment using an immunogold labeling technique reported in a previous paper, which showed the gold label to be located on the capsular surface area, also supports this notion (9). Regarding the mechanism of capsule size increase after reaction with the antibody, the following two possibilities are considered.…”

Section: Effect Of Monovalent Igg On Capsulessupporting

confidence: 62%

“…An encapsulated strain 277 (01: K2) and nonencapsulated strain 8N3 (01) of K. pneumoniae were used throughout the experiments. The origin and the biological characteristics of these strains have already been described in previous papers (9,10…”

mentioning

confidence: 88%

Electron Microscopic Observation of the Antibody‐Induced Capsular Swelling Phenomenon in Klebsiella pneumoniae

Meno

Amako

1996

The capsular swelling phenomenon of Klebsiella pneumoniae strain 277 was examined morphologically using the electron microscopy techniques of freeze-substitution. The capsules of strain 277 measured about 52 nm in thickness, and were composed of a number of fine fibers. After treating the bacteria with anti-capsular serum, the size of the capsules increased to about twice the normal size and they lost their electron density. The capsular fibers that are tightly packed in normal cells became loose and thus the identification of the individual capsular fibers was difficult in the swollen capsules. Capsule swelling was induced by washing the cells with phosphate-buffered saline. The removal of either divalent cations or some other materials might thus be important for maintaining the normal capsule structure. The mechanism of the swelling phenomenon was also discussed.

“…A thin section of the whole cell showed that the surface layer is always associated with the underlying outer membrane with a space but not with direct contact. Since the thin section technique that we used is a mild fixation method that preserves the fragile bacterial surface structure well (12,18), the space between the outer membrane and the surface layer protein should not be an artifact. These observations thus suggest that the surface layer proteins are not integrated components of the outer membrane but part of the external layer intimately associated with the outer membrane.…”

Section: Image Processing Of the Regular Patternmentioning

confidence: 99%

The Structure and Characterization of the Surface Protein Layer of a Comamonas‐Like Organism

Wai

Takade

Fujimoto

et al. 1995

The regular surface layer of a strain of a Comamonas‐like organism was examined by electron microscopy. The surface layer protein was easily extracted from the cell surface by a 2.5 M solution of lithium chloride. The protein subunit has a molecular size of 32,000 daltons, but usually forms a large aggregate of more than 1,200,000 daltons. In the extract it formed a regular array of p4 symmetry and was observed to be intimately associated with fragments of lipopolysaccharide. The size of a subunit determined by the negative staining method and the image processing method measured 5.2 × 6.4 nm (width and length), was arranged in a cobblestone‐like pattern, and was located in a lattice space measuring 13.0 nm square.