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.
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).
A
chromogen reagent (DAB) was added to the tissue sections.