To address this problem, the blue-white colorimetric screen was developed to allow on-plate screening of plasmid integration[3].
Cells were seeded on 96-well clear (for colorimetric assay) or white (for luminescence assays) tissue culture plates (1 2×104 cells/well, 4 wells/condition) and treated with drugs 18 24 h later.
Cells were transferred into a white 96-well plate suitable for colorimetric analysis (F96 MicroWell; Nunc, Germany), and generation of reactive oxygen species (ROS) was analyzed at an excitation wavelength of 485 nm and at an emission wavelength of 538 nm by using a fluorescence reader (Fluoroskan Ascent, Thermo Labsystems, Germany).
Degree of melanization (darkness) was quantified as the colorimetric measurement on the *L axis (white-black axis) of the CIE standard color axis.
Both screens use a colorimetric detection system in which prion-containing yeast cells form white colonies whereas loss of prion leads to formation of red colonies.
These compounds are all likely to be present in the bodies of flies, and could lead to a misinterpretation of the colorimetric assay results even if only bodies, or only white-eyed flies, are assayed.
We suggest that the image processing procedures should include 'sanity checks' at key points along the processing chain, for example to check on the tonal linearity of the data by using a neutral scale with multiple shades of grey from black to white, and to compare the reconstructed reflectance spectra against spectrophotometer reference measurements, including colorimetric measures.
CIE L∗ a∗ b∗ values were computed from XYZ tristimulus coordinates using colorimetric routines in the Psychophysics toolbox, and using the measured booth illuminant as the white point.
White blood cell (WBC) count was obtained using a counter S-plus IV and fibrinogen using a biuret colorimetric procedure and a clotting method.
In this study, the enzymatic activity of lysozyme in the core of polyion complex (PIC) micelles, which were formed from egg white lysozyme and poly ethylene glycol)–poly(α,β-aspartic acid) block copolymer (PEG-P(Asp)), was evaluated using a colorimetric method.
Nevertheless, introduction of CTXφ-derivatives in cells devoid of IMEXs led to fully white colonies or colonies with large white sectors around a blue star-shaped centre on X-gal plates in our colorimetric integration assay, indicating that the integration strategy of CTXφ was intrinsically highly efficient.
