Colony Spotting
Colony Spotting - Related Videos
10:45
Finding Your Blind Spot and Perceptual Filling-in
0 Views •
2023
Source: Laboratory of Jonathan Flombaum—Johns Hopkins University In the back of everyone's eye is a small piece of neural tissue called the retina. The retina has photosensitive cells that respond to stimulation by light. The responses of these cells are sent into the brain through the optic nerve, a bundle of neural fibers. In each retina there is a place somewhere in the periphery where the outputs from retinal cells collect and the bundled optic nerve exits to the brain. At that location,...
06:44
Keratinocyte Colony Formation Assay: An In Vitro Assay to Assess the Ability of Keratinocytes to Grow into Colonies
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2023
In this video, we perform a clonogenic assay of keratinocytes harvested from adult mice to determine the ability of individual cells to proliferate and form colonies. This keratinocyte harvesting technique is useful for studying other downstream aspects of cutaneous chemical carcinogenesis and tumor promotion.
05:10
A Spot Plate Assay for Evaluating Oxidative Stress Responses in Bacterial Strains
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2025
This video demonstrates a spot plate assay tailored to assess the oxidative stress responses of bacterial strains. Some strains produce pyomelanin, an antioxidant pigment. Conversely, strains treated with a test agent, leading to reduced pyomelanin production, exhibit increased susceptibility to oxidative stress, resulting in decreased cell viability compared to pyomelanin-producing strains.
08:38
Quantification of the Immunosuppressant Tacrolimus on Dried Blood Spots Using LC-MS/MS
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Cited by 28 •
2015
Here we describe a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) assay to quantify the immunosuppressant tacrolimus in dried blood spots using a simple manual protein precipitation step and online column extraction.
14:39
A Quantitative Assay for Insulin-expressing Colony-forming Progenitors
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Cited by 11 •
2011
A three-dimensional clonogenic assay that allows pancreatic-like progenitors to differentiate into insulin-expressing colonies is described. This method takes advantage of semi-solid media containing methylcellulose, Matrigel and growth factors, in which single progenitors proliferate and differentiate in vitro, permitting quantification of the number of functional progenitors in a population.
FAQs
Standardized placement is central to meaningful comparison. Depositing samples at defined positions on the same solid medium creates a shared growth environment, while the grid or other arrangement keeps sample identities traceable. After incubation, researchers can compare spot density, size, color, and morphology across strains or treatments, reducing confusion caused by examining samples on unrelated plates.
Spot appearance provides several observable indicators of microbial behavior. Colony size and density can reflect differences in growth or viability, while color and morphology can indicate distinct phenotypes. When samples receive different treatments or represent different strains, these visible contrasts help researchers identify altered growth patterns and select samples for further genetic or biological analysis.
Incubation under selected conditions determines whether transferred cells develop into visible spots and provides the basis for comparing their responses. If conditions differ between plates or do not suit the samples, growth patterns may be difficult to interpret. Consistent incubation allows observed differences in growth, viability, phenotype, or treatment response to be linked more clearly to the samples being tested.
The procedure requires a solid growth medium, typically an agar plate, together with a way to transfer cells accurately. A sterile loop, pipette tip, or multipoint inoculator can place individual colonies or small inocula at designated positions. Researchers also need an arrangement such as a grid and selected incubation conditions so the resulting spots remain organized and comparable.
First, researchers arrange positions on a solid growth medium and identify the samples to be compared. They then use a sterile loop, pipette tip, or multipoint inoculator to transfer colonies or small inocula to those locations. The plate is incubated under selected conditions, after which spot growth, density, color, and morphology are observed and compared.
This approach is useful when many microbial samples must be screened under comparable conditions on a single plate. Biology researchers apply it to strain screening, antibiotic sensitivity studies, and genetic analysis. It can also reveal treatment responses by showing whether samples differ in growth or viability, helping identify patterns that warrant more detailed investigation.