Toxicology application example

Comet Assay

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Comet Assay Screenshot

This software product was developed to automate the Single Cell Gel Electrophoresis comet assay.

The comet assay (also called single cell gel electrophoresis assay) allows the detection and the quantification of a broad spectrum of DNA damage induced by various agents in any individual cells. Using the alkaline version of the test, single and double strand breaks can be detected as well as alkali-labile and incomplete excision repair sites. Comet assay can be used to evaluate DNA repair capacity after irradiation or chemical exposure. Specific base modifications can also be detected after conversion into strand breaks by purified DNA repair enzymes. The wide spread applications of comet assay increase exponentially affecting many scientific disciplines such as genetic toxicology for in vitro and in vivo studies, as well as bio-monitoring, clinical and environmental researches. It is a very rapid, sensitive, cost-effective and easy test to perform, and more and more international laboratories use image processing techniques to analyze comets. Well-known laboratories are already using this software product (Agence Française de Sécurité Sanitaire des Aliments, International Agency for Research on Cancer, etc.).

The product includes:

  • Detection head and the tail of the comet
  • Detection of apoptotic cells
  • The calculation of statistical measures for comets and apoptosis
  • The calculation time of the comet tail

Key benefits of the software tool

  • Configurable (orientation, detection sensitivity, display options)
  • Automatic detection of comets
  • Automatic calculation of measures
    CometExtent, CometTotalIntensity, CometTotalArea, TailExtent, TailExtentMoment, TailOliveMoment, TailIntegratedIntensity, TailIntensityRatio, TailArea, TailBreaksNumber
  • Batch

It is currently the only software capable of detecting highly damaged cells. The analysis is independent of the initial electric field. The user can eliminate background noise and to identify cells too close. All measurements are calibrated and take into account the pixel size and the bias generated by sensors that are not square. It is possible to classify the cells into different categories and export related measures in Microsoft Excel. The resulting image showing the analysis is displayed on the screen with the display of the head and tail of the comet, as detected by the software, in terms of graphics. The software was developed in collaboration with the “Centre de Lutte contre le Cancer F. Baclesse” and “Groupe de Recherche en Informatique, Image, et Instrumentation de Caen (GREYC)”. It could, if necessary, be adapted to images acquired under slightly different.