Assay

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An assay is a procedure in molecular biology for testing or measuring the activity of a drug or biochemical in an organism or organic sample.[1][2] A quantitative assay may also measure the amount of a substance in a sample. Bioassays and immunoassays are among the many varieties of specialized biochemical assays. Other assays measure processes such as enzyme activity, antigen capture, stem cell activity, and competitive protein binding.

Contents

[edit] Assay varieties

[edit] Cytotoxicity

A cytotoxicity assay measures how toxic a chemical compound is to cells.

[edit] DNA

Assays for studying interactions of proteins with DNA include:

[edit] Protein

[edit] RNA

[edit] Cell counting, viability, proliferation or cytotoxicity assays

A cell-counting assay may determine the number of living cells, the number of dead cells, or the ratio of one cell type to another, such as numerating and typing red versus different types of white blood cells. This is measured by different physical methods (light transmission, electric current change). But other methods use biochemical probing cell structure or physiology (stains). Another application is to monitor cell culture (assays of cell proliferation or cytotoxicity).

[edit] Surfactants

[edit] Other cell assays

Many cell assays have been developed to assess specific parameters or response of cells (biomarkers, cell physiology. Techniques used to study_cells include :

[edit] Petrochemistry

[edit] Virology

The HPCE-based viral titer assay uses a proprietary, high-performance capillary electrophoresis system to determine baculovirus titer.

The Trofile assay is used to determine HIV tropism.

The viral plaque assay is to calculate the number of viruses present in a sample. In this technique the number of viral plaques formed by a viral inoculum is counted, from which the actual virus concentration can be determined.

[edit] Cellular secretions

A wide range of cellular secretions (say, a specific antibody or cytokine) can be detected using the ELISA technique. The number of cells which secrete those particular substances can be determined using a related technique, the ELISPOT assay.

[edit] Drugs

[edit] See also

[edit] References

  1. ^ The American Heritage Dictionary of the English Language. Fourth Edition. Houghton Mifflin Company: 2000.
  2. ^ McKean, Erin (ed.). The New Oxford American Dictionary. Second edition. Oxford University Press: 2005.
  3. ^ Lowry OH, Rosebrough NJ, Farr AL, Randall RJ (November 1951). "Protein measurement with the Folin phenol reagent". J. Biol. Chem. 193 (1): 265–75. PMID 14907713. http://www.jbc.org/cgi/pmidlookup?view=long&pmid=14907713. 
  4. ^ http://www.animal.ufl.edu/hansen/protocols/LOWRY.htm
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