Competent Cells
Competent Cells - Related Videos
01:28
Training and Competency in Animal Procedures
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2026
All animal procedures described here must be conducted in accordance with institutional animal ethics guidelines and approved by IACUC. All procedures must follow the principles of the 3Rs—Replacement, Reduction, and Refinement—and must be performed by trained personnel. A Stepwise Approach to Training Proper training and competency in animal procedures are essential to ensure high standards of animal welfare and reliable scientific outcomes. A structured, progressive training approach is...
03:13
Competence-Induced DNA Uptake in Staphylococcus aureus
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2025
Source: Cafini, F., et.al. Methodology for the Study of Horizontal Gene Transfer in Staphylococcus aureus. J. Vis. Exp. (2017)This video demonstrates competence-induced DNA uptake in Staphylococcus aureus through natural transformation. A chloramphenicol-sensitive strain engineered to constitutively express a sigma factor is cultured under nutrient-limiting conditions to enhance competence, then incubated with donor DNA carrying a resistance gene. Successful gene transfer is confirmed by the...
01:30
Symbolic Understanding I: Pictorial Competence
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2026
Symbolic understanding is the ability to use symbols, such as words, gestures, or images, to represent objects, people, and concepts that may not be physically present. An important part of this ability is pictorial competence, or the understanding that a picture represents something other than itself. For example, recognizing a yellow circle with rays as the sun shows pictorial competence.Early Responses to PicturesSome foundations of pictorial understanding appear early in infancy. By about...
10:35
Vector Competence Analyses on Aedes aegypti Mosquitoes using Zika Virus
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Cited by 3 •
2020
The presented protocol can determine the vector competence of Aedes aegypti mosquito populations for a given virus, such as Zika, in a containment setting.
04:05
Competition Binding Assay to Study Competing GTPase-Binding Protein Partners
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2025
This video demonstrates a competition assay to study GTPase-binding protein partners. Utilizing nucleotide-bound GTPase protein immobilized on magnetic beads, the competitive binding between two interacting protein partners for the same binding site on the GTPase can be studied to assess the binding affinities of the protein partners.
FAQs
Chemical preparation uses calcium ions to alter the cell envelope, whereas electroporation uses an electric field to create a temporary route for plasmid DNA entry. These approaches therefore differ in the physical trigger that enables uptake. The choice of treatment affects how cells are prepared and contributes to the resulting transformation efficiency.
Cell state matters because the envelope must respond effectively to the treatment used for DNA delivery. Cells in a suitable physiological condition are more likely to support uptake and recover afterward, while unsuitable conditions can reduce efficiency. This makes the condition of the starting cells an important variable when preparing or using competent cells.
Recovery gives transformed cells an opportunity to return to favorable growth conditions after DNA entry. This step is important because successful uptake alone does not guarantee that cells will survive or produce enough viable descendants for selection. In practice, recovery influences how many transformants become detectable on antibiotic-containing media.
A typical workflow begins by introducing plasmid DNA into prepared cells using chemical treatment or an electric field. Researchers then allow the cells to recover under favorable conditions before placing them on antibiotic-containing media. Surviving colonies provide a selected population for cloning, plasmid amplification, protein expression, or strain construction.
Antibiotic-containing media provide a selection step after recovery. Cells that acquired the relevant plasmid can grow under the stated selection condition, whereas cells lacking it are not retained in the selected population. The resulting growth pattern helps researchers identify transformants for subsequent molecular biology work.
Competent cells support several core genetic-engineering tasks: cloning genes, amplifying plasmids, expressing recombinant proteins, and constructing engineered strains. Each application uses DNA uptake as an entry point followed by recovery and selection to retain cells carrying the intended genetic material. Consequently, these preparations connect DNA introduction with downstream biological outcomes.