Plasmid Add-back
Plasmid Add-back - 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.
01:27
Conjugate Addition (1,4-Addition) vs Direct Addition (1,2-Addition)
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2025
α,β-Unsaturated carbonyl compounds with two electrophilic sites, the carbonyl carbon, and the β carbon, are susceptible to nucleophilic attack via two modes: conjugate or 1,4-addition and direct or 1,2-addition. Conjugate addition results in a thermodynamically stable product. The reaction retains the stronger C=O bond at the expense of the weaker C=C π bond. The process is slow as the β carbon is less electrophilic than the carbonyl carbon. Direct addition products are formed faster owing to...
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.
01:08
Conjugate Addition of Enolates: Michael Addition
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2023
The attack of a nucleophile at the β carbon of an α,β-unsaturated carbonyl compound is called conjugate addition. Conjugate addition reactions of active methylene compounds, such as β-diketones, β-keto esters, β-keto nitriles, and α-nitro ketones, are called Michael addition reactions. The reaction is catalyzed by a base that abstracts the acidic methylene hydrogen, generating a doubly-stabilized enolate ion that serves as the nucleophile or the Michael donor. The base employed depends on the...
FAQs
Restoration of the missing trait strengthens the causal link between a gene and a biological function. If a mutant or gene-deleted organism regains a phenotype after receiving the relevant genetic sequence, the result supports the idea that loss of that gene caused the defect. This evidence is especially useful for validating knockout or knockdown findings and separating a specific genetic effect from broader secondary changes.
Plasmid add-back can reintroduce more than a coding sequence. The construct may carry the target gene, its regulatory region, or a functional variant, depending on the question being tested. Comparing these forms can help investigators examine whether the phenotype depends on the gene product, its regulation, or a particular functional version, while the plasmid must remain compatible with the recipient cells.
Controls establish whether an observed change is attributable to the introduced genetic material. Researchers compare the deficient organism with appropriate control conditions and assess the same relevant traits, such as growth or expression. These comparisons help distinguish restoration caused by the add-back from changes that arise secondarily during mutation, gene deletion, or experimental handling.
An experiment generally begins by cloning the target gene, regulatory region, or functional variant into a compatible plasmid. The resulting construct is then introduced into the mutant or gene-deleted cells. Researchers compare those cells with appropriate controls and evaluate growth, expression, or another relevant phenotype. This sequence connects construct design with functional interpretation.
Growth and gene expression are two central readouts, but the comparison can also include other phenotypic traits relevant to the biological question. A restored growth pattern may indicate recovery of a cellular function, whereas expression measurements can show whether the introduced sequence is associated with the expected molecular change. Results are interpreted against controls.
Researchers commonly apply plasmid add-back after a knockout or knockdown has produced a candidate phenotype. Reintroducing the relevant genetic material provides a follow-up test of whether that phenotype is connected to the disrupted gene rather than only to an indirect consequence of the experiment. This makes the method useful for functional genomics and gene-function studies.
In biology, the technique is particularly relevant to microbial genetics, molecular biology, and functional genomics. Its value extends across these areas because the same experimental logic can connect a disrupted gene with changes in growth, expression, or another phenotype. By restoring the relevant genetic element and comparing outcomes, investigators can strengthen functional assignments from genetic experiments.