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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).

McGraw-Hill Concise Encyclopedia of Bioscience. © 2002 by The McGraw-Hill Companies, Inc.


(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.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Table I.- LC50 values for different essential oils against CLM larvae by using two bioassay techniques.
The second bioassay was conducted for 20 d with 10 shrimp (452 [+ or -] 50 mg) per glass aquarium with 4 L of seawater and constant aeration.
To form a training set of compounds for modeling, public in vitro bioassay data for 7,385 compounds were extracted from PubChem ( using an automatic data mining portal ( (Russo et al.
OA starts to affect gene expression at 25 nM and results in a clear profile at 100 nM, similar to the profile obtained with DTX-1 at 9 nM, indicating that DTX-1 is about 4 times more potent than OA and in line with the relative potencies as observed in the neuro-2a bioassay (Bodero et al., 2018a,b).
* Currently Available GF Bioassays Service: sh-Polypeptide-l(FGF2), -3(FGF7), -4(SCF), -7(hGH), -9(VEGF), -10(FGF10), -11(FGF1), -28(PRL), -40(hPL), -71 (VIP), -78(HSP90A), sh-Oligopeptide-1(EGF), -4(TMS)
Our results indicate that this bioassay is useful in order to obtain information about the susceptibility of mosquitoes towards different substances such as natural and conventional insecticides in commercial formulations, as well as for entomopathogenic fungi.
Detection and activity profiling of synthetic cannabinoids and their metabolites with a newly developed bioassay. Anal Chem2 016;88:11476-85.
Previous work involving bioassays with larval melolonthids has been inconsistent, largely because these bioassays have been performed using larvae collected in the field because breeding these species is difficult as a result of their annual cycles and underground habit.
In addition to brine shrimp lethal bioassay, in vitro antibacterial activities were also carried out for the synthesized biphenyl analogues.
* New areas, new requirements how bioassay meets gene therapy and CAR-T technologies?