Bacterial Transformation
Bacterial Transformation - Related Videos
05:21
Bacterial Transformation - Student Protocol
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2019
Bacterial Transformation ExpandIMPORTANT: In addition to wearing the appropriate personal protective equipment, be sure to take care to keep your face away from suspension cultures, and to avoid inhaling reagents. Do not touch your face while performing the experiment. Always wash your hands before and after every experiment. When you are ready to safely begin, check to make sure you have a tube or tubes of competent E. coli cells in your ice bucket. Then, transfer 50 µL from one of these tubes...
04:33
Bacterial Transformation - Concepts
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2019
Background In early 20th century, pneumonia was accountable for a large portion of infectious disease deaths1. In order to develop an effective vaccine against pneumonia, Frederick Griffith set out to study two different strains of the Streptococcus pneumoniae: a non-virulent strain with a rough appearance (R-strain) and a virulent strain with a smooth appearance (S-strain) due to an outer polysaccharide capsule2. This outer layer of the S-strain bacteria enabled them to withstand the host...
01:33
Bacterial Transformation
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2021
In 1928, bacteriologist Frederick Griffith worked on a vaccine for pneumonia, which is caused by Streptococcus pneumoniae bacteria. Griffith studied two pneumonia strains in mice: one pathogenic and one non-pathogenic. Only the pathogenic strain killed host mice.Griffith made an unexpected discovery when he killed the pathogenic strain and mixed its remains with the live, non-pathogenic strain. Not only did the mixture kill host mice, but it also contained living pathogenic bacteria that...
12:19
Bacterial Transformation: Electroporation
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2023
The term “transformation” refers cellular ingestion of foreign DNA. In nature, transformation can occur in certain types of bacteria. In molecular biology, however, transformation is artificially induced through the creation of pores in the bacterial cell walls. Bacterial cells that are able to take up DNA from the environment are called competent cells. Electrocompetent cells can be produced in the laboratory and transformation of these cells can be achieve via the application of an...
11:01
Bacterial Transformation: The Heat Shock Method
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2023
Transformation is the process that occurs when a cell ingests foreign DNA from its surroundings. Transformation can occur in nature in certain types of bacteria. In molecular biology, transformation is artificially reproduced in the lab via the creation of pores in bacterial cell membranes. Bacterial cells that are able to take up DNA from the environment are called competent cells. In the laboratory, bacterial cells can be made competent and DNA subsequently introduced by a procedure called...
FAQs
Natural transformation depends on a bacterium’s ability to become competent, bind extracellular DNA, and transport it across the cell envelope. Laboratory transformation instead uses chemical treatment or electroporation to increase cellular receptivity, commonly allowing plasmids to enter. This distinction separates a naturally occurring route of genetic exchange from an experimentally induced method for introducing selected DNA constructs.
After foreign DNA enters a naturally competent cell, homologous recombination can align matching DNA sequences and incorporate the incoming material into the bacterial chromosome. This step matters because uptake alone does not necessarily produce a heritable change. When chromosomal integration occurs, the acquired sequence can alter inherited traits and contribute to bacterial genetic variation.
Competence describes the cellular state that permits bacteria to bind and transport DNA across the cell envelope. In natural transformation, it determines whether extracellular genetic material can enter the cell. In laboratory work, chemical treatment or electroporation is used to make cells more receptive, increasing the likelihood that introduced plasmids will enter and support downstream selection or expression.
Plasmid-based transformation introduces DNA using a plasmid, making it useful for engineering cells to carry selected genes, produce recombinant proteins, or express genetic constructs. Chromosomal incorporation, associated with homologous recombination, places incoming DNA within the bacterial chromosome. The two approaches therefore differ in where the genetic material is maintained and how researchers study inherited changes.
A laboratory workflow first prepares bacterial cells to become more receptive to DNA through chemical treatment or electroporation. Researchers then introduce a plasmid carrying the desired genetic material and use an antibiotic-resistance marker to identify cells that acquired the construct. The resulting selected cells can support studies of gene function or recombinant protein production.
Antibiotic-resistance markers provide a selectable trait for identifying bacterial cells that acquired an introduced plasmid. After transformation, researchers can use the marker to distinguish engineered cells from cells that did not receive the construct. This makes transformation practical for building recombinant strains and for linking DNA uptake with a recoverable experimental outcome.