What does a comet assay show?
Comet assay is a microgel electrophoresis technique, which detects DNA damage and repair in individual cells. The assay measures DNA damage (i.e., strand breaks, DNA adducts, excision repair sites, and cross-links) at the single-cell level.
What is tail moment?
The tail moment is defined as the product of the tail length and the fraction of total DNA in the tail (Tail moment=tail length x % of DNA in the tail). This is calculated automatically by the computer software system as an average for the 50 cells selected for measurement.
Is comet assay quantitative?
10.3. 1 Introduction. The Comet assay is a relatively simple, sensitive, and quantitative method to study DNA damage (including oxidative damage) and repair at the level of the individual cell. Initially developed by Singh et al.
Why are comet assays performed?
The comet assay is a versatile technique for detecting damage and with adjustments to the protocol can be used to quantify the presence of a wide variety of DNA altering lesions (damage). The damage usually detected are single strand breaks and double strand breaks.
Is comet assay reliable?
Introduction. Testing of chemicals for genotoxicity requires methods that are sensitive and specific, preferably economical and quick, and reliable. The alkaline (pH > 13) comet assay (single-cell gel electrophoresis) meets most of these requirements, but is regarded by some as unreliable.
What is an olive moment?
Olive tail moment: this is defined as the product of the tail length and the fraction of total DNA in the tail.
What is tail length in comet assay?
(1988) developed the alkaline version of the Comet Assay in which they used the length of DNA migration (tail length) to quantify the extent of damage. Subsequently, several research groups published papers in which various Comet Assay parameters were used (Table 1).
What is alkaline comet assay?
Introduction. The alkaline comet assay is a technically simple, sensitive assay to detect DNA damage (strand breaks and other lesions that are converted into strand breaks under alkaline conditions) and DNA repair activity1,2,3,4.
What causes DNA damage?
DNA damage occurs continuously as a result of various factors—intracellular metabolism, replication, and exposure to genotoxic agents, such as ionizing radiation and chemotherapy. If left unrepaired, this damage could result in changes or mutations within the cell genomic material.
How many cells does a comet assay have?
Thus by counting a representative sample of ∼ 100–300 cells per tissue it is possible to arrive at the average percentage of DNA damage accumulated in a particular tissue due to genotoxic stress. The comet assay is also referred to as SCGE assay.