Single-Cell Gel Electrophoresis or Comet Assay of Intestinal Epithelial Cells Using Manual Scoring and Ridit Analysis

  • Mark M. Huycke
Part of the Methods in Pharmacology and Toxicology book series (MIPT)


The single-cell gel electrophoresis or comet assay was initially reported in 1984 as a novel technique to directly visualize DNA damage in individual cells (1). The method was modified by adding strong alkaline conditions to denature genomic DNA and detect alkali labile lesions, greatly improving sensitivity for single-strand breaks (2,3). This simple assay has come into widespread use because of its sensitivity, need for few cells, applicability to nearly all eukaryotic cells, and ease in processing numerous samples (4).


Comet Assay Comet Tail Ethidium Bromide Solution Comet Tail Length Ridit Analysis 
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  1. 1.
    Östling, O. and Johanson, K. J. (1984) Microelectrophoretic study of radiation-induced DNA damages in individual mammalian cells. Biochem. Biophys. Res. Commun. 123, 291–298.PubMedCrossRefGoogle Scholar
  2. 2.
    Olive, P. L., Banáth, J. P., and Durand, R. E. (1990) Heterogeneity in radiation-induced DNA damage and repair in tumour and normal cells measured using the “comet” assay. Radiat. Res. 122, 86–94.PubMedCrossRefGoogle Scholar
  3. 3.
    Singh, N. P., McCoy, M. T., Tice, R. R., and Schneider, E. L. (1988) A simple technique for quantitation of low levels of DNA damage in individual cells. Exp. Cell Res. 175, 184–191.PubMedCrossRefGoogle Scholar
  4. 4.
    Fairbairn, D. W., Olive, P. L., and O’Neill, K. L.(1995) The comet assay: a comprehensive review. Mutation Res. 339, 37–59.PubMedGoogle Scholar
  5. 5.
    Fleiss, J. L. (1981) The comparison of proportions from several independent samples: ridit analysis, in Statistical Methods for Rates and Proportions, 2nd ed. John Wiley & Sons, New York, pp. 150–157.Google Scholar
  6. 6.
    Klaude, M., Eriksson, S., Nygren, J., and Ahnström, G. (1996) The comet assay: mechanisms and technical considerations. Mutation Res. 363, 89–96.PubMedCrossRefGoogle Scholar
  7. 7.
    Tice, R. R. (1995) The single cell/gel comet assay: a microgel electrophoretic technique for the detection of DNA damage and repair in individual cells, in Environmental Mutagenesis. (Phillips, D. H. and Venitt, S., eds.) Bios Scientific Publishers, Oxford, pp. 315–339.Google Scholar
  8. 8.
    Strauss, G. H. S. (1991) Non-random cell killing in cryopreservation: implications for performance of the battery of leukocyte tests (BLT), I. Toxic and immunotoxic effects. Mutat. Res. 252, 1–15.PubMedGoogle Scholar
  9. 9.
    McKelvey-Martin, V. J., Green, M. H. L., Schmezer, P., Pool-Zobel, B. L., De Méo, M. P., and Collins, A. (1993) The single cell gel electrophoresis assay (comet assay): a European review. Mutat. Res. 288, 47–63.PubMedGoogle Scholar
  10. 10.
    Huycke, M. M., Abrams, V., and Moore, D. R. (2002) Enterococcus faecalis produces extracellular superoxide and hydrogen peroxide that damages colonic epithelial cell DNA. Carcinogenesis 23, 529–536.PubMedCrossRefGoogle Scholar
  11. 11.
    Huycke, M. M., Moore, D., Shepard, L., et al. (2001) Extracellular superoxide production by Enterococcus faecalis requires demethylmenaquinone and is attenuated by functional terminal quinol oxidases. Mol. Microbiol. 42, 729–740.PubMedCrossRefGoogle Scholar

Copyright information

© Humana Press Inc.,Totowa, NJ 2003

Authors and Affiliations

  • Mark M. Huycke
    • 1
    • 2
    • 3
  1. 1.The Muchmore Laboratories for Infectious Diseases ResearchUniversity of Oklahoma Health Sciences CenterOklahoma City
  2. 2.Research Service, Department of Veterans Affairs Medical CenterUniversity of Oklahoma Health Sciences CenterOklahoma City
  3. 3.Department of MedicineUniversity of Oklahoma Health Sciences CenterOklahoma City

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