Plasmid Linearization
Plasmid Linearization - 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.
06:35
Linearization of the Bradford Protein Assay
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Cited by 292 •
2010
The accuracy and sensitivity of protein determination by the rapid and convenient Bradford assay is compromised by intrinsic nonlinearity. We show a simple linearization procedure that greatly increases the accuracy, improves the sensitivity of the assay about 10-fold, and significantly reduces interference by detergents.
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 restriction endonuclease recognizes a defined sequence within the plasmid and cuts at that site. The location of this recognition site determines where the circular molecule opens, while the enzyme’s cutting pattern determines whether the resulting DNA has blunt ends or cohesive ends. Selecting an appropriate site therefore supports controlled preparation for subsequent molecular biology experiments.
The cut pattern determines the physical character of the resulting DNA ends. Blunt ends have no single-stranded overhangs, whereas cohesive ends contain complementary overhanging sequences. This distinction provides information about how the plasmid was processed and can influence its suitability for downstream experimental use, including preparation of DNA templates for immunology and infection studies.
Complete digestion indicates that the restriction endonuclease has processed the plasmid population as intended at the selected recognition site. This matters because incomplete cutting can leave a mixture of molecular forms that complicates interpretation. Confirming completeness strengthens confidence that the material used in later analyses represents the planned linearized template rather than an unresolved mixture.
A defined restriction pattern provides a practical check on whether a plasmid behaves as expected when cut. The resulting DNA size or banding pattern can be examined after digestion, helping investigators assess plasmid identity and integrity. This verification is especially valuable when plasmids support reporter assays, recombinant antigen studies, cytokine experiments, or DNA vaccine development.
A typical workflow selects a restriction endonuclease with a suitable recognition site, exposes the plasmid to the enzyme so the defined cut can occur, and then evaluates the digestion product. Gel electrophoresis or another sizing method verifies the expected linear DNA form and helps determine whether digestion was complete before downstream experimental use.
Linearized plasmids can support DNA template preparation, recombinant antigen studies, cytokine research, reporter assays, and DNA vaccine development. In each setting, the controlled DNA form helps standardize material used for experimental analysis. The approach is therefore relevant when researchers need dependable plasmid templates to examine expression-related questions or immune-modulating strategies.
In this field, reliable DNA templates support investigations of host responses, pathogen biology, and immune-modulating therapies. Linearization contributes by helping confirm plasmid identity and integrity before those experiments proceed. Its value is therefore both preparative and quality-related: it supplies material for selected studies while improving confidence that experimental results derive from the intended plasmid construct.