Navigation Links
Ames test


The Ames test is a biological assay used in genetics, generally genetic toxicology , to test for mutagenic properties of a chemical compound. A compound is said to be mutagenic if it causes a change in the DNA (deoxyriboneucleic acid) of a living cell or organism. The test is named after its inventor, Bruce Ames.

General procedure

This assay is carried out using strains of bacteria, generally Escherichia coli or Salmonella that already have a single mutation, for example, a strain that cannot produce histidine, an amino acid that is essential for the bacterium to grow if not provided externally with essential nutrients. Cultures of the bacteria are grown in an agar containing dish so that a "lawn" of bacteria is present. The experimental cultures are exposed to the agent to be tested while the positive control cultures are exposed to a known mutagen to confirm that there has been no contamination of the strain. Strains of bacteria are available which have been genetically modified such that only a certain type of mutation (i.e. a base pair mutation or a frameshift mutation) will cause the strand to revert to a normal state, not requiring nutrients to grow. If the mutation screened for has in fact occurred dense spots in the colonies will form. A certain number of spots may form due to random mutation not caused by the agent; therefore, data analysis using control dishes is necessary. Occasionally a tested agent will be toxic enough to simply kill the bacterial culture in which case a "thin lawn" is observed.

S-9

In some Ames assays an S-9 mix is added. The S-9 mix contains liver enzymes, generally from a rat. These enzymes can metabolize the agent being tested in order to predict the mutagenic properties within a living system, specifically the source of the S-9 enzymes.

Mutagenic and carcinogenic correlation

Studies have shown that the majority of substances shown to be mutagenic by an Ames assay will be carcinogenic in humans.


'"/>


(Date:7/9/2014)... one gene for another in a line of living ... reality within this decade. As with any new technology, ... disease-causing genes in humans, for example--as well as questions ... of those concerns to rest: using gene-editing techniques on ... in the cells. The new results were published July ...
(Date:7/9/2014)... As climate change shifts the geographic ranges in which ... it has on their parasites. Does an increased range ... as well? , Not necessarily, says a team of ... Armand Kuris. In a study published in the ... that for some species, the opposite may happen: Hosts ...
(Date:7/9/2014)... Fla. (July 9, 2014) Emerging fungal pathogens ... other parasitic group, causing population declines of amphibians, ... the University of South Florida published in the ... can acquire behavioral or immunological resistance to a ... declines. , "Acquired resistance is important because ...
Breaking Biology News(10 mins):No extra mutations in modified stem cells, study finds 2No extra mutations in modified stem cells, study finds 3Not at home on the range 2Not at home on the range 3Not at home on the range 4USF study: Amphibians can acquire resistance to deadly fungus 2
... are developing new technologies that combine a laser ... particles such as bacteria, viruses and DNA for ... to food safety. The technologies could bring ... or miniature instruments that perform measurements normally requiring ...
... have no way of predicting which threatened miscarriages will ... we are unable to target attempts to rescue the ... counselling," she said. "This has led to wasteful and ... hospital admissions for bed rest, sexual abstinence, low dose ...
... For the first time, fertility experts have shown that, ... poor oral health can have a significant effect on the ... meeting of the European Society of Human Reproduction and Embryology ... of the same order of magnitude as the effect of ...
Cached Biology News:Laser, electric fields combined for new 'lab-on-chip' technologies 2Laser, electric fields combined for new 'lab-on-chip' technologies 3Researchers can predict accurately the outcome of pregnancies threatening to miscarry 2Gum disease can increase the time it takes to become pregnant 2Gum disease can increase the time it takes to become pregnant 3
Other biology definitionOther Tags