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Bioassay (commonly used shorthand for biological assay or assessment), or biological standardization is a type of scientific experiment. A bioassay involves the use of live animal or plant (in vivo) or tissue or cell (in vitro) to determine the biological activity of a substance, such as a hormone or drug. Bioassays are typically conducted to measure the effects of a substance on a living organism and are essential in the development of new drugs and in monitoring environmental pollutants. Both are procedures by which the potency or the nature of a substance is estimated by studying its effects on living matter. A bioassay can also be used to determine the concentration of a particular constitution of a mixture that may cause harmful effects on organisms or the environment.

Use[edit]

Bioassays are procedures that can determine the concentration or purity or biological activity of a substance such as vitamin, hormone or plant growth factor by measuring the effect on an organism, tissue, cells, enzyme or receptor. Bioassays may be qualitative or quantitative. Qualitative bioassays are used for assessing the physical effects of a substance that may not be quantified, such as seeds fail to germinate or develop abnormally deformity. An example of a qualitative bioassay includes Arnold Adolph Berthold's famous experiment on castrated chickens. This analysis found that by removing the testicles of a chicken, it would not develop into a rooster because the endocrine signals necessary for this process were not available. Quantitative bioassays involve estimation of the concentration or potency of a substance by measurement of the biological response that it produces. Quantitative bioassays are typically analyzed using the methods of biostatistics. For more information Look up Basic and Clinical Pharmacology by Bertram G. Katzung.

Definition[edit]

"The determination of the relative strength of a substance (e.g., a drug or hormone or toxicant) by comparing its effect on a test organism with that of a standard preparation." is called bioassay. ....

Purpose[edit]

  1. Measurement of the pharmacological activity of new or chemically undefined substances
  2. Investigation of the function of endogenous mediators
  3. Determination of the side-effect profile, including the degree of drug toxicity
  4. Measurement of the concentration of known substances (alternatives to the use of whole animals have made this use obsolete)
  5. Assessing the amount of pollutants being released by a particular source, such as wastewater or urban runoff.
  6. Determining the specificity of certain enzymes to certain substrates.

Types[edit]

Bioassays are of two types:

Quantal[edit]

A quantal assay involves an "all or none response".

Graded[edit]

Graded assays are based on the observation that there is a proportionate increase in the observed response following an increase in the concentration or dose. The parameters employed in such bioassays are based on the nature of the effect the substance is expected to produce. For example: contraction of smooth muscle preparation for assaying histamine or the study of blood pressure response in case of adrenaline.

A graded bioassay can be performed by employing any of the below-mentioned techniques. The choice of procedure depends on:

  1. the precision of the assay required
  2. the quantity of the sample substance available
  3. the availability of the experimental animals.

Techniques[edit]

  1. Matching Bioassay
  2. Interpolation Method
  3. Bracketing Method
  4. Multiple Point Bioassay (i.e.-Three-point, Four-point and Six Point Bioassay)
  5. divided bioassy

Matching Bioassay: It is the simplest type of the bioassay. In this type of bioassay, response of the test substance taken first and the observed response is tried to match with the standard response. Several responses of the standard drug are recorded till a close matching point to that of the test substance is observed. A corresponding concentration is thus calculated. This assay is applied when the sample size is too small. Since the assay does not involve the recording of concentration response curve, the sensitivity of the preparation is not taken into consideration. Therefore, precision and reliability is not very good.

Interpolation bioassay: Bioassays are conducted by determining the amount of preparation of unknown potency required to produce a definite effect on suitable test animals or organs or tissue under standard conditions. This effect is compared with that of a standard. Thus the amount of the test substance required to produce the same biological effect as a given quantity the unit of a standard preparation is compared and the potency of the unknown is expressed as a % of that of the standard by employing a simple formula.


Many times, a reliable result cannot be obtained using this calculation. Therefore it may be necessary to adopt more precise methods of calculating potency based upon observations of relative, but not necessarily equal effects, likewise, statistical methods may also be employed. The data (obtained from either of assay techniques used) on which bioassay are based may be classified as quantal or graded response. Both these depend ultimately on plotting or making assumption concerning the form of DRC.

Environmental bioassays[edit]

Environmental bioassays are generally a broad-range survey of toxicity. A toxicity identification evaluation is conducted to determine what the relevant toxicants are. Although bioassays are beneficial in determining the biological activity within an organism, they can often be time-consuming and laborious. Organism-specific factors may result in data that is not applicable to others in that species. For these reasons, other biological techniques are often employed, including radioimmunoassays. See bioindicator.

Water pollution control requirements in the United States require some industrial dischargers and municipal sewage treatment plants to conduct bioassays. These procedures, called whole effluent toxicity tests, include acute toxicity tests as well as chronic test methods. The methods involve exposing living aquatic organisms to samples of wastewater.[1][2] For example the bioassay ECOTOX uses the microalgae Euglena gracilis to test the toxicity of water samples. [3] (See Bioindicator#Microalgae as bioindicators and water quality)

See also[edit]

References[edit]

  1. ^ United States Environmental Protection Agency (EPA). Washington, DC. "Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms." October 2002. Document No. EPA-821-R-02-012.
  2. ^ US EPA. "Whole Effluent Toxicity / Clean Water Act Analytical Methods." Accessed December 16, 2008.
  3. ^ Tahedl, Harald; Hader, Donat-Peter (1999). "Fast examination of water quality using the automatic biotest ECOTOX based on the movement behavior of a freshwater flagellate". Water Research 33 (2): 426–432. doi:10.1016/s0043-1354(98)00224-3. 

External links[edit]


Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/Bioassay — Please support Wikipedia.
This page uses Creative Commons Licensed content from Wikipedia. A portion of the proceeds from advertising on Digplanet goes to supporting Wikipedia.

744 news items

 
News-Medical.net
Wed, 01 Jul 2015 23:22:30 -0700

Domainex Ltd, a private drug discovery service company, today announces that it is launching an integrated bioassay service platform, BioassayBuilder. The new platform expands on the existing protein expression, hit identification and medicinal ...
 
BMC Blogs Network
Thu, 02 Jul 2015 08:33:45 -0700

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original ...

Genetic Engineering & Biotechnology News

Genetic Engineering & Biotechnology News
Thu, 14 May 2015 12:49:50 -0700

There is urgent need for a simple, easy-to-use, robust, cell-based functional bioassay to measure potency of a candidate drug during the development of therapeutic mAbs that block the interaction of PD-1:PD-L1 for drug discovery and development. Such ...
 
Nature.com
Tue, 30 Jun 2015 23:21:44 -0700

Bioassay-guided fractionation using the extract led to the isolation of five compounds (1–5), of which 1 (plicacetin), 2 (norplicacetin) and 5 were identified as cytosine-type nucleoside derivatives, by comparison of their spectral data with those ...
 
Nature.com
Tue, 30 Jun 2015 23:21:44 -0700

Article | PubMed |; Osada, H., Cui, C. B., Onose, R. & Hanaoka, F. Screening of cell cycle inhibitors from microbial metabolites by a bioassay using a mouse cdc2 mutant cell line, tsFT210. Bioorg. Med. Chem. 5, 193–203 (1997). | Article | PubMed | CAS ...

TheHorse.com

TheHorse.com
Sat, 27 Jun 2015 05:00:00 -0700

These products require a successful field bioassay before an alternative sensitive crop should be planted. Also, composted manure from animals that have been fed hay produced from fields treated with aminopyralid can harm sensitive plants. Always ...
 
Stockhouse
Wed, 01 Jul 2015 06:30:00 -0700

VistaGen is also developing and using pluripotent stem cell technology and clinically-predictive bioassay systems, CardioSafe 3D™ and LiverSafe 3D™, for drug rescue applications focused on producing proprietary new chemical entities (NCEs) for its ...
 
BMC Blogs Network
Fri, 26 Jun 2015 04:15:00 -0700

The bioassay for GLP1 used HEK cells expressing the GLP-1R; synthetic GLP1-Ser8 was used as the standard and had an EC 50 of 2.8 pM (Fig. 7a). The NH 2 -terminus of GLP1 plays an essential role in its interaction with receptor and the addition of the ...
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