Plasmid Mobilization
Plasmid Mobilization - 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 92 •
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.
06:57
Electrophoretic Mobility Shift Assay (EMSA)
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2023
The electrophoretic mobility shift assay (EMSA) is a biochemical procedure used to elucidate binding between proteins and nucleic acids. In this assay a radiolabeled nucleic acid and test protein are mixed. Binding is determined via gel electrophoresis which separates components based on mass, charge, and conformation. This video shows the concepts of EMSA and a general procedure, including gel and protein preparation, binding, electrophoresis, and detection. Applications covered in this video...
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.
FAQs
The origin of transfer, or oriT, identifies the DNA region where transfer begins, while the relaxase recognizes this site and nicks one DNA strand. The relaxase then guides that strand toward the mating-pair formation system. These coordinated roles connect plasmid-specific DNA processing with cell-to-cell transfer and help determine whether a plasmid can be mobilized.
A mobilizable plasmid can depend on a conjugative plasmid or other helper functions to provide the mating-pair formation system. The mobilizable element supplies transfer-associated information such as oriT and relaxase recognition, while the helper supplies the system that connects bacterial cells. This division explains why transfer capacity can depend on interactions among multiple plasmids.
Single-strand nicking creates the DNA form that the relaxase can guide through the mating-pair formation system. Because the process targets one DNA strand rather than treating the plasmid as an undifferentiated molecule, oriT recognition and relaxase activity become essential control points. Studying these steps helps explain how specific plasmids enter horizontal gene transfer pathways.
Plasmid mobilization can disseminate genes associated with antibiotic resistance, virulence, or specialized metabolism. Their movement between bacterial cells can alter traits in recipient populations and contribute to genome evolution. The same transfer process therefore has consequences ranging from the emergence of resistant bacteria to the acquisition of capabilities that support particular ecological or metabolic lifestyles.
Researchers can use plasmid mobilization as a framework for examining how antibiotic-resistance genes move across bacterial populations. Attention to oriT, relaxase activity, and helper functions can connect a resistance trait with its potential transfer mechanism. This perspective supports investigation of resistance emergence as a population-level genetic process rather than only as a property of individual bacterial cells.
The process provides a way to move DNA between microbial hosts, making it relevant to genetic tools as well as to natural genome evolution. Researchers can study which plasmid features support transfer and use mobilization to examine gene behavior in different bacterial contexts. Its value extends beyond disease-related traits to the broader experimental movement of microbial DNA.