An assay is a procedure where the concentration of a component part of a mixture is determined. In chemistry, concentration is the measure of how much of a given substance there is mixed with another substance. ... In chemistry, a mixture is the product of a mechanical blending or mixing of chemical substances like elements and compounds, without chemical bonding or other chemical change, so that each ingredient substance retains its own chemical properties and makeup. ...

There are numerous applications of an assay, such as an antigen capture assay, bioassay, competitive protein binding assay, four-point assay, immunoassay, microbiological assay, stem cell assay, and many others. Also known as a biological assay, a bioassay is a measurement of the effects of a substance on living organisms. ...

In the laboratory

Assays are regularly utilized in scientific research laboratories. Biochemistry laboratory at the University of Cologne. ...

DNA

Assays for studying interactions of protein with DNA include: Interaction is a kind of action which occurs as two or more objects have an effect upon one another. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... The general structure of a section of DNA Deoxyribonucleic acid (DNA) is a nucleic acid — usually in the form of a double helix — that contains the genetic instructions or genocode monitoring the biological development of all cellular forms of life, and many viruses. ...

• DNase footprinting assay
• electron microscopy
• filter binding
• gel shift assay

A DNase footprinting assay [1]is a technique from molecular biology that detects DNA-protein interaction using the fact that a protein bound to DNA will often protect that DNA from enzymatic cleavage. ... The electron microscope is a microscope that can magnify very small details with high resolving power due to the use of electrons rather than light to scatter off material, magnifying at levels up to 500,000 times. ... Lane 1 is a negative control, and only contains only DNA. Lane 2 contains protein as well as a DNA fragment that, based on its sequence, does not interact. ...

Protein

• Bicinchoninic acid assay (better known as the BCA assay)
• Bradford protein assay
• Lowry protein assay
• Secretion assay
• ultraviolet spectroscopy

The Bicinchoninic acid assay or BCA assay is a biochemical assay for detecting the presence of protein in a solution, similar to Lowry protein assay, Bradford protein assay or biuret reagent. ... The Bradford protein assay is a spectroscopic analytical procedure used to measure the concentration of protein in a solution. ... Principle Under alkaline conditions the divalent copper ion forms a complex with peptide bonds in which it is reduced to a monovalent ion. ... Secretion assay is a process used in cell biology to identify cells that are secreting a particular protein (usually a cytokine). ... Ultraviolet-visible spectroscopy or ultraviolet-visible spectrophotometry (UV/ VIS) involves the spectroscopy of photons and spectrophotometry. ...

Cytotoxicity

Assays for studying how toxic a compound is to cells:

• MTT assay
• SRB (Sulforhodamine B) assay

MTT assay is a laboratory test and a standard colorimetric assay (an assay which measures changes in colour) for measuring cellular proliferation (cell growth). ...

Viruses

The number of viruses present in a sample can be determined using a viral plaque assay. This technique requires counting the number of plaques formed by a virus sample, from which the actual virus concentration can be determined. Groups I: dsDNA viruses II: ssDNA viruses III: dsRNA viruses IV: (+)ssRNA viruses V: (-)ssRNA viruses VI: ssRNA-RT viruses VII: dsDNA-RT viruses A virus (Latin, poison) is a microscopic particle that can infect the cells of a biological organism. ... A viral plaque is a visible structure formed within a cell culture, such as bacterial cultures within some nutrient medium (e. ...

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. Schematic of antibody binding to an antigen An antibody is a protein used by the immune system to identify and neutralize foreign objects like bacteria and viruses. ... Cytokines is a group of proteinaceous signalling compounds that like hormones and neurotransmitters are used extensively for inter-cell communication. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... ELISPOT is an immunological assay based on ELISA (Enzyme-Linked Immunosorbent Assay). ...

Drugs

Illegal drug testing A drug test is a process using some kind of biological matter taken from an individual to determine previous drug use. ...

Environmental contaminants

• Lead
• Coliform bacteria
• Arsenic

General Name, Symbol, Number lead, Pb, 82 Chemical series poor metals Group, Period, Block 14, 6, p Appearance bluish white Atomic mass 207. ... Coliform bacteria are used often as an indicator of sanitary quality of foods and water. ... General Name, Symbol, Number arsenic, As, 33 Chemical series metalloids Group, Period, Block 15, 4, p Appearance metallic gray Atomic mass 74. ...

Coins

A 19th century assay laboratory in Tombstone Courthouse State Historic Park, Arizona.

An assayer is often assigned to each mint to determine and assure that all coins produced there have the correct content or purity of each metal in them. This is particularly important with gold and silver coins. Download high resolution version (2145x1950, 396 KB)Historical (gold & silver) assay lab in Tombstone Courthouse State Historic Park, Tombstone, AZ. Taken 8/12/03 by Pretzelpaws with a Canon 10D camera and cropped using the Gimp. ... Download high resolution version (2145x1950, 396 KB)Historical (gold & silver) assay lab in Tombstone Courthouse State Historic Park, Tombstone, AZ. Taken 8/12/03 by Pretzelpaws with a Canon 10D camera and cropped using the Gimp. ... Official language(s) English Capital Phoenix Largest city Phoenix Area  Ranked 6th  - Total 113,998 sq mi (295,254 km²)  - Width 310 miles (500 km)  - Length 400 miles (645 km)  - % water 0. ... A mint is a facility which manufactures coins for currency. ... A coin is usually a piece of hard material, generally metal and usually in the shape of a disc, which is issued by a government to be used as a form of money. ... Content can mean Comfort and a feeling of satisfaction Creations, as in open content or free content. ... ... To meet Wikipedias quality standards, this article or section may require cleanup. ... General Name, Symbol, Number gold, Au, 79 Chemical series transition metals Group, Period, Block 11, 6, d Appearance metallic yellow Atomic mass 196. ... General Name, Symbol, Number silver, Ag, 47 Chemical series transition metals Group, Period, Block 11, 5, d Appearance lustrous white metal Atomic mass 107. ...