Characterization of translucent segments observed in an smbA mutant of Escherichia coli

Authors

  • Kunitoshi Yamanaka,

    Corresponding author
    1. Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University School of Medicine, Kumamoto 862, Japan
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  • Teru Ogura,

    1. Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University School of Medicine, Kumamoto 862, Japan
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  • Kazuyoshi Murata,

    1. Laboratories of Cell Biology, Faculty of Integrated Arts and Sciences, Hiroshima University, Hiroshima 730, Japan
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  • Toshinobu Suzaki,

    1. Laboratories of Cell Biology, Faculty of Integrated Arts and Sciences, Hiroshima University, Hiroshima 730, Japan
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  • Hironori Niki,

    1. Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University School of Medicine, Kumamoto 862, Japan
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  • Sota Hiraga

    1. Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University School of Medicine, Kumamoto 862, Japan
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*Corresponding author. Tel: (096) 344 2111 (ext. 6762); Fax: (096) 371 2408.

Abstract

Abstract The smbA gene of Escherichia coli is essential for cell proliferation. The smbA2 mutant shows cold-sensitive colony formation at 22°C. A novel morphological phenotype, formation of a translucent segment at midcell or at a cell pole, was observed by phase-contrastt microscopy at a high frequency in the smbA2 mutant cells incubated in L medium lacking NaCl at 22°C, but not observed in L medium containing 1% NaCl or 20% sucrose at the same temperature. No translucent segment was observed in the wild-type cells in any of the media used. Electron microscopic observation revealed that the translucent segments resulted from the enlargement of a periplasmic space by separation of the inner membrane from the peptidoglycan layer and the outer membrane.

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