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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 larval bioassay used a similarly prepared dilution series to determine the effect on first instar larval mosquitoes.
A total of 45 third-instar larvae of P vetula were used per treatment, and 225 were used per bioassay.
What other technologies can be brought in as a future bioassay platform?
The consistency of the mAb/ligand interaction is supported by the fact that the (inhibition) bioassay gave virtually identical results for all originator lots as well as all biosimilar candidates.
Additionally, the bioassay system provided clues to the major mechanisms of cardiac cytotoxicity induced by each compound, thus enabling not only the identification of toxicities early in the drug development process, but also discovery of potential mechanisms of action.
2003, 2005) reported the baseline susceptibilities to imidacloprid for Aphis pomi De Geer and Aphis spiraecola Patch by using a dip bioassay technique.
After each decontamination, the plates were allowed to dry for 48 hours before the insect bioassay was performed.
This is the first demonstration that gold nanoparticles can be grown when entrapped in silica and the first report of sol-gel-based inks being used to produce a dipstick-based bioassay.
Key words: Tagosodes orizicolus, Homoptera, rice delphacid, bioassay, rearing, sugar diet, Bacillus thuringiensis, [delta]-endotoxins.
Users can create and recall automatic scanning patterns for different plate configurations, AutoZONE is ideal for applications including multi-zone bioassay plate analysis (commonly 36 and 64 zone plates) and Single Radial Immunodiffusion assay plates.