Plasmid Screening
Plasmid Screening - Related Videos
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.
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.
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.
01:28
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...
09:44
High-throughput Screening for Chemical Modulators of Post-transcriptionally Regulated Genes
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2015
Here we describe a cell-based reporter gene assay as a valuable tool to screen chemical libraries for compounds modulating post-transcriptional control mechanisms exerted through 3’ UTR.
FAQs
Antibiotic selection enriches for bacterial cells that retained a plasmid carrying the matching resistance marker, but it does not prove that the recombinant insert is correct. Resistant colonies can still contain unwanted or incomplete constructs. Researchers therefore treat growth as an initial filter, then apply a construct-specific check such as colony PCR, restriction enzyme digestion, or sequencing.
Each assay contributes a different level of construct checking. Colony PCR can indicate whether the expected insert is present in a candidate colony, whereas restriction enzyme digestion provides another way to examine the recombinant DNA. DNA sequencing supports verification of the construct’s sequence. Using these checks together helps separate apparently positive colonies from constructs that are incomplete or otherwise incorrect.
Insert presence and insert orientation are separate questions. A colony may contain recombinant DNA while the inserted sequence is arranged differently from the intended design. Plasmid screening therefore includes checks capable of addressing orientation, not only whether an insert exists. Confirming this feature is important before treating a candidate plasmid as the correct construct for later biological experiments.
Sequence-based verification provides confidence that engineered DNA matches the intended design. This check can reveal whether the construct’s sequence agrees with the planned recombinant plasmid, rather than relying only on antibiotic resistance or a preliminary structural test. Performing it before downstream work reduces the risk of building experiments on an incorrect plasmid.
A typical workflow begins after transformation by enriching bacteria with the appropriate antibiotic selection. Researchers then examine candidate colonies using colony PCR, restriction enzyme digestion, or DNA sequencing, depending on the verification question. Results are used to identify cells carrying the desired construct and to exclude unwanted or incomplete plasmids before the selected material enters a downstream experiment.
Plasmid screening supports several stages of biological research, including gene cloning, protein expression, genome editing, and functional studies. In each case, the screen acts as a checkpoint before the construct is used for the next experiment. Confirming plasmid identity at that point helps researchers work with the intended genetic design rather than an unverified recombinant.
Reliable screening saves time and reduces errors caused by carrying an incorrect construct into later work. Sequence verification adds confidence when exact agreement with the intended design matters. Together, these outcomes make screening a quality-control step that supports more dependable downstream experiments in biology, particularly when the recombinant plasmid will guide cloning, expression, editing, or functional analysis.