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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 ?
We initially performed CDC bottle bioassays to develop time-series mortality curves to determine insecticide susceptibility in these geographically separate populations.
50] bioassays, a total of 600 first-instar larvae of P vetula were field-collected at the same site but were maintained at 25 [+ or -] 1[degrees]C up to the third instar.
At the conclusion of the meeting, the insights gained at this event will give biologics researchers a better understanding of bioassays that reflect true MOA, are robust, sensitive and reproducible.
Additionally, bioassay analysis and the physicochemical analyses sited above were performed on these same lots of originator material.
In relation to the concentrations in the tested solutions of STX and neoSTX, there was a difference in the production of neoSTX between the two cultures of CYRF used in the bioassays (number 1 and remaining assays--Table 1).
Also, the transaction includes an earn-out of EUR1m based on Cisbio Bioassays consolidated results in 2013, an earn-out of EUR1.
In previous works, most resistance monitoring data of insect pests reported were obtained by various bioassays, and the resistance levels were normally evaluated by comparing data tested in different years, only few susceptible strains and baseline data were used.
At the end of each bioassay, the tested insects were destroyed and not used for subsequent bioassays.
IGF has collaborated with Cisbio Bioassays on a number of projects over the past decade, and extensively tested and validated Tag-lite for dimerization," said Dr.
In this report, we present the development of a procedure to establish a healthy and stable RDel colony that may provide enough test individuals for bioassays.
Crown gall tumours on potato discs and brine shrimp lethality: two simple bioassays for higher plant screening and fractionation.