Archives of Microbiology

, Volume 113, Issue 3, pp 197–204 | Cite as

Dorsal-ventral differentiation in Simonsiella and other aspects of its morphology and ultrastructure

  • Jack Pangborn
  • Daisy A. Kuhn
  • Janie R. Woods


The morphology and ultrastructure of the aerobic, Gram-negative multicellular-filamentous bacteria of the genus Simonsiella were investigated by scanning and transmission electron microscopy. The flat, ribbon-shaped, multicellular filaments show dorsal-ventral differentiation with respect to their orientations to solid substrata. The dorsal surface, orientated away from the substrate, is convex and possesses an unstructured capsule. The ventral surface, on which the organisms adhere and glide, is concave and has an extracellular layer with fibrils extending at right angles from the cell wall. The cytoplasm in the ventral region contains a proliferation of intracytoplasmic membranes and few ribosomes in comparison to the cytoplasm in other parts of the cell. Centripetal cell wall formation is asymmetrical and commences preferentially in the ventral region. Quantitative differences in morphology and cytology exist among selected Simonsiella strains. Functional aspects of this dorsalventral differentiation are discussed with respect to the colonization and adherence of Simonsiella to mucosal squamous epithelial cells in its ecological habitat, the oral cavities of warm-blooded vertebrates.

Key words

Gliding bacterium Simonsiella Oral cavity Electron microscopy Morphology Dorsal-ventral differentiation Ultrastructure 

List of Abbreviations


scanning electron microscope


transmission electron microscope


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  1. Anderson, T. F.: Techniques for the preservation of three-dimensional structure in preparing specimens for the electron microscope. Trans. N.Y. Acad. Sci., Ser. II, 13, 130–134 (1951)Google Scholar
  2. Barnett, M. L.: Adherence of bacteria to oral epithelium in vivo: Electron microscopic observations. J. dent. Res. 52, 1160 (1973)Google Scholar
  3. Costerton, J. W., Ingram, J. M., Cheng, K.-J.: Structure and function of the cell envelope of Gram-negative bacteria. Bact. Rev. 38, 87–110 (1974)Google Scholar
  4. Fox, E. N.: M proteins of group A streptoccocci. Bact. Rev. 38, 57–86 (1974)Google Scholar
  5. Gibbons, R. J., van Houte, J.: Bacterial adherence in oral microbial ecology. Ann. Rev. Microbiol. 29, 19–44 (1975)Google Scholar
  6. Henriksen, S. D.: “Pitting” and “corrosion” of the surface of agar cultures by colonies of some bacteria from the respiratory tract. Acta path. microbiol. scand., Sect. B 82, 48–52 (1974)Google Scholar
  7. Kuhn, D. A., Gregory, D. A., Nyby, M. D., Mandel, M.: Deoxyribonucleic acid base composition of Simonsiellaceae. Arch. Microbiol. 113, 205–207 (1977)Google Scholar
  8. Kuhn, D. A., Nyby, M. D., Pangborn, J., Mandel, M.: Comparative characteristics of Simonsiella strains. First International Congress for Bacteriology, Jerusalem, Abstracts II, p. 260 (1973)Google Scholar
  9. Leak, L. V.: Fine structure of the mucilaginous sheath of Anabaena sp. J. Ultrastruct. Res. 21, 61–74 (1967)Google Scholar
  10. Müller, R.: I. Zur Stellung der Krankheitserreger im Natursystem. II. Demonstrationen. Mundbakterien et al. III. Paratyphustochterkolonien in Typhuskolonien. Münch. med. Wschr. 42, 2247–2248 (1911)Google Scholar
  11. Pangborn, J., Kuhn, D. A., Woods, J. R.: Dorsoventral differentiation in Simonsiella. First International Congress for Bacteriology, Jerusalem, Abstracts II, p. 164 (1973)Google Scholar
  12. Pangborn, J., Kuhn, D. A., Woods, J. R.: A bacterium with dorsoventral differentiation. J. Ultrastruct. Res. 48, 173 (1974)Google Scholar
  13. Pangborn, J., Marr, A. G., Robrish, S. A.: Localization of respiratory enzymes in intracytoplasmic membranes of Azotobacter agilis. J. Bact. 84, 669–678 (1962)Google Scholar
  14. Patterson, H., Irvin, R., Costerton, J. W., Cheng, K. J.: Ultrastructure and adhesion properties of Ruminococcus albus. J. Bact. 122, 278–287 (1975)Google Scholar
  15. Reynolds, E. S.: The use of lead citrate at high pH as an electronopaque stain in electron microscopy. J. Cell Biol. 17, 208–213 (1963)Google Scholar
  16. Ryter, A., Kellenberger, E.: Étude au microscope électronique de plasmas contenant de l'acide desoxyribonucléique. I. Les nucléoides des bactéries en croissance active. Z. Naturforsch. 13B, 597–605 (1958)Google Scholar
  17. Steed, P. D. M.: Simonsiellaceae fam. nov. with characterization of Simonsiella crassa and Alysiella filiformis. J. gen. Microbiol. 29, 615–624 (1962)Google Scholar
  18. Wagner, R. C., Barnett, R. J.: The fine structure of prokaryoticeukaryotic cell junctions. J. Ultrastruct. Res. 48, 404–413 (1974)Google Scholar

Copyright information

© Springer-Verlag 1977

Authors and Affiliations

  • Jack Pangborn
    • 1
  • Daisy A. Kuhn
    • 2
  • Janie R. Woods
    • 1
  1. 1.Facility for Advanced InstrumentationUniversity of CaliforniaDavisUSA
  2. 2.Department of BiologyCalifornia State UniversityNorthridgeUSA

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