Letter | Published:

A Vacuolar System in Cells of Agrobacterium tumefaciens as shown by Electron Microscopy of Ultra-thin Sections

Naturevolume 187pages10431044 (1960) | Download Citation



ELECTRON microscope studies of ultra-thin sections of the cells of several species of bacteria made by different workers have shown a regular structural pattern which can be summarized as follows : a definite cell wall, a cytoplasmic membrane (Chapman1), a granular cytoplasm with one or more round, dense inclusions called chondrioids (Kellenberger et al.2), and a more or less central core which is irregular in shape and low in density to the electron beam. Comparative studies of stained preparations with the light microscope have led various workers to associate this core with nuclear structures, and it has been called vesicular nucleus, kernvacuole, kernäquivalent, nucleoide, nuclear sites, and nuclear apparatus. Reticulated structures within this core have been considered to be nuclear material, deoxyribonucleic acid or even chromosomes.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Chapman, G., J. Bact., 78, 96 (1959).

  2. 2

    Kellenberger, E., Ryter, A., and Séchaud, J., J. Biophys. Biochem. Cytol., 4, 671 (1958).

  3. 3

    Houwink, A. L., J. Gen. Microbiol., 15, 146 (1956).

  4. 4

    Knaysi, G., J. Bact., 74, 12 (1957).

  5. 5

    Birch-Andersen, A., and Maaløe, O., Biochim. Biophys. Acta, 12, 395 (1953).

  6. 6

    Knaysi, G., J. Bact., 69, 117 (1955).

  7. 7

    Preusser, H. J., Arch. Mikrobiol., 33, 105 (1959).

Download references

Author information


  1. Instituto “Jaime Ferran” de Microbiologia, Madrid

  2. Department of Plant Pathology, Citrus Experiment Station, University of California, Riverside, California



  1. Search for MIGUEL RUBIO-HUERTOS in:

  2. Search for PAUL R. DESJARDINS in:

About this article

Publication history

Issue Date




By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.