Counter Screening
Counter Screening - Related Videos
09:33
Determining Cell Number During Cell Culture using the Scepter Cell Counter
0 Views •
Cited by 56 •
2010
The Scepter Cell Counter is a handheld automated device that can be used to count cells, monitor cell diameter and volume, and be used to check the health and quality of cellular populations from one culture to the next.
09:44
High-throughput Screening for Chemical Modulators of Post-transcriptionally Regulated Genes
0 Views •
2015
Here we describe a cell-based reporter gene assay as a valuable tool to screen chemical libraries for compounds modulating post-transcriptional control mechanisms exerted through 3’ UTR.
13:16
Determination of Mammalian Cell Counts, Cell Size and Cell Health Using the Moxi Z Mini Automated Cell Counter
0 Views •
Cited by 18 •
2012
The Moxi Z miniature automated cell counter is a novel instrument that combines the Coulter Principle with patented thin-film sensor technology and a proprietary software algorithm to perform sizing and counting of a broad size range of particles as well as to determine the overall health of monodisperse mammalian cell cultures. This protocol describes the use of this instrument for counting and assessing the health of cell cultures.
08:50
Genetic Screens
0 Views •
2023
Genetic screens are critical tools for defining gene function and understanding gene interactions. Screens typically involve mutating genes and then assessing the affected organisms for phenotypes of interest. The process can be “forward”, where mutations are generated randomly to identify unknown genes responsible for the phenotypes, or it can be “reverse”, where specific genes are targeted for mutation to observe what phenotypes are produced.Here, JoVE reviews various types of genetic...
08:10
Multi-enzyme Screening Using a High-throughput Genetic Enzyme Screening System
0 Views •
Cited by 7 •
2016
This work presents a method of high-throughput screening using a universal genetic enzyme screening system that can be theoretically applied to over 200 enzymes. Here, the single screening system identifies three different enzymes (lipase, cellulase, and alkaline phosphatase) by simply changing the substrate used (p-nitrophenyl acetate, p-nitrophenyl-β-D-cellobioside, and phenyl phosphate).
FAQs
Comparison with the primary assay result is central because activity alone does not establish selective target engagement. If a compound also acts in related or unrelated systems, its signal may reflect nonspecific behavior rather than the intended mechanism. The comparison therefore helps prioritize hits whose activity is more plausibly mechanism-based.
Testing related and unrelated targets serves different interpretive purposes. Related targets reveal whether a hit lacks selectivity within a biological family or pathway, whereas unrelated targets and control systems can expose broader nonspecific activity. Reading these patterns alongside primary-screen data helps researchers distinguish a focused signal from a compound that behaves similarly across multiple experimental contexts.
Assay interference must be considered because a measured signal can reflect the testing system rather than the intended biological target. Counter screening addresses this risk by examining compounds in control systems and secondary assays designed to reveal unwanted activity or interference. Removing such hits early prevents misleading results from being treated as evidence of selective target engagement.
After a primary screen, researchers test candidates against related and unrelated targets, control systems, or sources of common experimental interference. The selected secondary assays therefore probe whether the original signal persists outside the intended target context. This design connects each counter screen to a specific concern, including selectivity, nonspecific activity, or an assay-related artifact.
Researchers compare counter-screening results with the original primary-screen data rather than interpreting secondary activity in isolation. A candidate that retains an appropriate primary signal while showing unwanted activity elsewhere may be eliminated. In contrast, a more selective pattern supports advancing a hit for target validation and later studies.
Counter screening is especially useful when early hits must be triaged before costly downstream work. By identifying nonspecific compounds and assay-related problems at an early stage, it improves hit quality, informs target validation, and reduces the chance that unsuitable candidates advance into later studies.