Chromogen


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Related to Chromogen: Auxochrome

chromogen

[′krō·mə‚jen]
(biochemistry)
A pigment precursor.
(microbiology)
A microorganism capable of producing color under suitable conditions.

Chromogen

 

according to the color theory devised by O. Witt, a substance containing chromophores—groups of atoms responsible for the coloration of various compounds. The term was also used to designate colorless substances found in animal and plant tissues that become pigments as a result of oxidation. V. I. Palladin proposed the term “respiratory chromogen” as part of his theory of plant respiration in reference to substances that become pigments through reversible oxidation. The equivalent Russian term is no longer used in the literature.

References in periodicals archive ?
Organic chromogens are taken up by the pellicle and the color imparted is determined by the natural color of the chromogen and the color seen on the tooth is considered to be derived mostly from polyphenolic compounds (15,16).
The principle of this method is based on staining of chromogen DAB which will bind with the antibody of p53, Bcl-2, Caspases 8 and 9, and formed brown color on the cell membrane.
Chromogen was applied for 20 minutes and all the slides were counter-stained with haematoxylin dehydrated and mounted.
The medium also possesses an enhanced dual chromogen system that ensures colonies of Salmonella are always green while non-target organisms appear black or colourless, for clear differentiation.
After washing the wells, a chromogen substrate (tetramethylbenzidine) is added and incubated, leading to color development which is proportional to the amount of malaria antibodies present in the sample.
In the presence of an acidic buffer with a pH of 5.2 (S2) and a suitable oxidant (Fe[Cl.sup.3+]) (S3), a stable and colored radical solution is formed by the chromogen that contains 4-amino-N, N-diethylaniline sulfate.
DMC possesses carbonyl group (C=O) of the chromogen (Ar-COCH=CH-Ar) as an intermediate which can produce deeper colour during the reaction by a phenomenon known as "Halochromy" [30].
The peroxidase reaction was developed using 3-amino-9-ethylcarbazol (AEC) as a chromogen and the immunostained sections were screened under a light microscope.
3-Amino-9-ethylcarbazole (AEC, Vector Laboratories, Burlingame, CA, USA) was used as chromogen and slides were slightly counterstained with Mayer's hematoxylin.
Creatinine with picric acid in alkaline environment (NaOH) creates the chromogen. Chromogen absorbance was measured at wave length of 450 nm using Creatinine Analyzer 2 (Beckman, Munich, Germany).
CPCs were detected using a monoclonal antibody directed against PSA, clone 28A4 (Novocastra Laboratory, UK), and identified using an alkaline phosphatase-anti alkaline phosphatase-based system (LSAB2, DAKO, USA), with New Fuschin as the chromogen. Positive samples underwent a second process with anti-P504S clone 13H4 (DAKO, USA) and identified with a peroxidase-based system (LSAB2, DAKO, USA) with DAB (3,3'diaminobenzidine tetrahydrochloride) as the chromogen, according to the manufacturers' instructions.