Plasmid Introduction
Plasmid Introduction - Related Videos
08:16
Plasmid Purification
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2023
Plasmid purification is a technique used to isolate and purify plasmid DNA from genomic DNA, proteins, ribosomes, and the bacterial cell wall. A plasmid is a small, circular, double-stranded DNA that is used as a carrier of specific DNA molecules. When introduced into a host organism via transformation, a plasmid will be replicated, creating numerous copies of the DNA fragment under study. In this video, a step-by-step generalized procedure is described for how to perform plasmid purification.
01:28
Plasmids
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2025
Plasmids are extrachromosomal DNA molecules found in bacteria, archaea, and some eukaryotic microbes like yeast. These small, circular DNA structures typically contain fewer than 30 genes, although some may exist linearly. Plasmids vary in their number within a cell, known as copy number. Single-copy plasmids are present in one copy per cell and multi-copy plasmids are present in multiple copies, reaching over 100 copies per cell.Plasmids usually replicate independently of the chromosomal DNA...
07:11
Homemade Site Directed Mutagenesis of Whole Plasmids
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Cited by 91 •
2009
Site directed mutagenesis of whole plasmids is a simple way to create slightly different variations of an original plasmid. Here we demonstrate an easy and cost effective way to introduce base substitutions into a plasmid using standard reagents.
02:41
Amplification of a Suicide Plasmid in a Bacterial Host
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2025
Source: Tomás, J. M., et al. Generation of Null Mutants to Elucidate the Role of Bacterial Glycosyltransferases in Bacterial Motility. J. Vis. Exp. (2022).This video demonstrates the initiator-dependent amplification of a suicide plasmid in E. coli. The plasmid, which carries an antibiotic resistance gene, replicates only in the presence of an initiator protein encoded by the host. After electroporation and incubation in recovery medium, the mixture is plated on antibiotic-containing agar.
08:57
High-throughput Yeast Plasmid Overexpression Screen
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Cited by 12 •
2011
Here we describe a plasmid overexpression screen in Saccharomyces cerevisiae, using an arrayed plasmid library and a high-throughput yeast transformation protocol with a liquid handling robot.
FAQs
Both approaches create temporary membrane permeability, allowing circular DNA to cross into living cells. Heat shock uses a temperature-based treatment, whereas electroporation uses an electrical treatment. Because the membrane disruption is temporary, cells can remain viable while gaining access to the introduced plasmid, enabling subsequent genetic expression or plasmid replication.
Competent cells are prepared to receive plasmid DNA efficiently during the introduction step. Their condition directly affects whether the construct can enter the cell and produce a detectable outcome. In bacterial transformation, preparing cells for competence is therefore an essential part of connecting the delivery method with successful genetic modification.
An introduced plasmid can provide genetic information that the host cell expresses, allowing researchers to examine a gene or produce a recombinant protein. The same construct can also replicate inside the cell, enabling amplification of a DNA sequence. These outcomes make plasmids useful for both functional studies and biotechnology workflows.
A typical workflow begins by making bacterial cells competent, exposing them to the selected plasmid DNA, and applying heat shock or electroporation to promote entry. Researchers then use a selectable marker to identify cells that acquired the construct. The resulting selected cells can support further analysis of gene expression, protein production, or DNA amplification.
Selectable markers provide a way to distinguish cells that received the plasmid from those that did not. After the introduction step, researchers apply the marker-based selection and identify cells showing the expected selectable outcome. This converts plasmid uptake from an otherwise difficult-to-observe event into a practical means of finding candidate modified cells.
Researchers use this technique to produce recombinant proteins, investigate gene function, build reporter systems, and amplify DNA sequences. In functional genomics, it helps connect introduced genetic information with biological effects. In synthetic biology and biotechnology, plasmid-based constructs provide a practical foundation for testing engineered genetic systems and generating useful biological products.