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A method for the quantitation of the effects on a biological system by its exposure to a substance, as well as the quantitation of the concentration of a substance by some observable effect on a biological system. The biological material in which the effect is measured can range from subcellular components and microorganisms to groups of animals. The substance can be stimulatory, such as an ion increasing taxis behavior in certain protozoans, or inhibitory, such as an antibiotic for bacterial growth. Bioassays are most frequently used when there is a number of steps, usually poorly understood, between the substance and the behavior observed, or when the substance is a complex mixture of materials and it is not clear what the active components are. Bioassays can be replaced, in time, by either a more direct measure of concentration of the active principle, such as an analytical method (for example, mass spectrometry, high-pressure liquid chromatography, radioimmunoassay), or a more direct measurement of the effect, such as binding to a surface receptor in the case of many drugs, as the substance or its mechanism of action is better characterized.

Assays to quantitate the effects of an exposure model the effect of a substance in the real world. Complex biological responses can be estimated by laboratory culture tests, which use, for example, bacteria or cells cultured in a petri dish (usually to model an effect either on the organism of interest, such as bacteria, or on some basic cellular function); by tissue or organ culture, which isolates pieces of tissue or whole organs in a petri dish (usually to model organ function); or in whole animals (usually to model complex organismic relationships).


(analytical chemistry)
A method for quantitatively determining the concentration of a substance by its effect on the growth of a suitable animal, plant, or microorganism under controlled conditions.
References in periodicals archive ?
The Bioassays conference is one of the tracks at the Immunogenicity & Bioassay Summit 2015.
frugiperda was determined on each maize-leaf piece from activity of spinosad alone and spinosad-SfMNPV mixture bioassays described above.
The test vessels for the fungal bioassay were 250-mL screw-cap glass jars each containing 150 g of "Toolangi forest loam" soil moistened to 60 percent MC.
For the bioassay, 10 RFB adults were counted into small disposable Petri dishes and allowed to starve overnight.
at different concentrations using the brine shrimp lethality bioassay.
The detection limit of the bioassay, defined as the testosterone concentration that produced a luciferase activity 2 SD above the mean of 10 samples of charcoal-stripped serum (used to reduce the contaminating steroids from the serum), was 0.
Pettis based the bioassay on one that he and ARS entomologists Mark F.
No single bioassay meets all of these requirements, so a combination of different bioassays is, undoubtedly, the best approach to screening.
We're also building a a flow-through bioassay facility allowing us to do more sophisticated testing on estrogen and many other compounds.
The company's LabMAPTM system is an open-architecture, multi-analyte technology platform that delivers fast, accurate and cost-effective bioassay results to markets as diverse as pharmaceutical drug discovery, clinical diagnostics and biomedical research.
Chronic effects are estimated by dose-response studies on animals, carcinogenic effects are estimated by a carcino-genesis bioassay, and acute toxic effects are estimated by LD5O studies of observation of accidents.
Under the agreement, Life Technologies will develop, distribute and market reagents and instrumentation based on Luminex' open platform LabMAP bioassay technology.