Freeze-Etch Study of Pseudomonas aeruginosa : Localization Within the Cell Wall of an Ethylenediaminetetraacetate-Extractable Component

作者：H. E. Gilleland, J. Dwight Stinnett, Ivan L. Roth, Robert G. Eagon · 发表于：Journal of Bacteriology · 年份：1973 · DOI：10.1128/jb.113.1.417-432.1973 · 被引用次数：64 · 研究领域：Bacterial biofilms and quorum sensing、Protein purification and stability

A freeze-etch study of normal cells of Pseudomonas aeruginosa and of cells after incubation with ethylenediaminetetraacetate (EDTA) and tris(hydroxymethyl)aminomethane (Tris) was performed. When cells were freeze-etched without a cryoprotective agent, a smooth outer cell wall layer, which showed a regular array of subunits, and the presence of flagella and pili were observed. These features were not observed in cells freeze-etched after cryoprotection with glycerol. Four fracture surfaces, which resulted from splitting down the center of the outer wall membrane and of the inner cytoplasmic membrane, were revealed in freeze-etched glycerol-protected cells. The murein layer was seen in profile between the outer cell wall membrane and the cytoplasmic membrane. Spherical units and small rods composed of the spherical units were observed in the inner layer of the outer cell wall membrane. These spherical units appeared to be attached to, or embedded in, the inner face of the outer layer of the outer cell wall membrane. These spherical units were removed from cells on exposure to EDTA-Tris, resulting in cells that were osmotically fragile. The spherical units were detected via electron microscopy of negatively stained preparations in the supernatant fluid of cellular suspensions treated with EDTA-Tris. Upon addition of Mg(2+), the spherical units were reaggregated into the inner layer of the outer cell wall membrane and the cells were restored to osmotic stability. The spherical un...