Letter | Published:

Localization of Inhibitors of Neural Differentiation in Chick Embryos

Naturevolume 192pages997998 (1961) | Download Citation



IN testing the hypothesis of specific inhibition in cellular differentiation, I have shown1 that early chick embryos, when cultured on a nutrient medium which has incorporated in it supernatants of adult and embryonic brain extracts, displayed homologous brain defects in a significant number of cases. Since the preparation of subcellular components has become a standard technique for problems of cellular chemistry (see review by Allfrey2), this investigation was prompted with the hope of localizing the inhibitory material in the crude brain extracts to a particular cell fraction. Accordingly, chick brains were homogenized and subjected to differential centrifugation in order to obtain mitochondrial, microsomal, and soluble protein fractions. Earlier investigations of Braverman3 and Lenicque4 showed that the nuclear fraction is not involved. The procedure used for culturing chick embryos was that of Spratt5. Since I have found1 that stages 4 and 5 (ref. 6) are the crucial stages for treatment with brain extracts, the assay for inhibitory activity was restricted to the use of these stages.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Katoh, A. K., J. Morph., 138 (in the press).

  2. 2

    Allfrey, V., The Cell, 1, 193 (Academic Press, New York, 1959).

  3. 3

    Braverman, M. H., Biol. Bull., 115, 319 (1958).

  4. 4

    Lenicque, P., Acta Zool., 40, 141 (1959).

  5. 5

    Spratt, jun., N. T., J. Exp. Zool., 106, 345 (1947).

  6. 6

    Hamburger, V., and Hamilton, H. L., J. Morph., 88, 49 (1951).

  7. 7

    Hasselbach, W., and Schneider, G., Biochem. Z., 321, 462 (1951).

Download references

Author information

Author notes

  1. A. K. KATOH: Postdoctoral Fellow of the U.S. National Science Foundation.


  1. Biological Institute, Nagoya University, Chikusa-ku, Nagoya

    • A. K. KATOH


  1. Search for A. K. KATOH in:

About this article

Publication history

Issue Date



Further reading


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.