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The term plasmid was coined in 1952 by the American molecular biologist Joshua Lederberg to refer to "any extrachromosomal hereditary determinant." [14] [15] The term's early usage included any bacterial genetic material that exists extrachromosomally for at least part of its replication cycle, but because that description includes bacterial viruses, the notion of plasmid was refined over time ...
Many biotechnology applications utilize mutated plasmids that replicate to high copy number. For example, pBR322 is a medium copy number plasmid (~20 copies/cell) from which several high copy number cloning vectors (>100 copies/cell) have been derived by mutagenesis, such as the well known pUC series. [ 1 ]
Other cloning vectors include the pUC series of plasmids, and a large number of different cloning plasmid vectors are available. Many plasmids have high copy numbers, for example, pUC19 has a copy number of 500-700 copies per cell, [6] and high copy number is useful as it produces greater yield of recombinant plasmid for subsequent manipulation ...
A bacterial artificial chromosome (BAC) is a DNA construct, based on a functional fertility plasmid (or F-plasmid), used for transforming and cloning in bacteria, usually E. coli. [ 1 ] [ 2 ] [ 3 ] F-plasmids play a crucial role because they contain partition genes that promote the even distribution of plasmids after bacterial cell division.
For instance, if there are 2 copies of a plasmid in a cell, there is 50% chance of having one plasmid-less daughter cell. However, high-copy number plasmids have a cost for the hosting cell. This metabolic burden is lower for low-copy plasmids, but those have a higher probability of plasmid loss after a few generations.
The pUC plasmids are all circular double stranded DNA about 2700 base pairs in length. [3] The pUC plasmids are some of the most widely used cloning vectors. [ 3 ] This is in part because cells that have successfully been transformed can be easily distinguished from those that have not based on color differences of colonies.
This is a quantification of how many cells were altered by 1 μg of plasmid DNA. In essence, it is a sign that the transformation experiment was successful. [1] It should be determined under conditions of cell excess. [2] Transformation efficiency is typically measured as the number of transformed cells per total number of cells.
Plasmids and bacteriophages are usually replicated as single replicons, but large plasmids in Gram-negative bacteria have been ... there are multiple replicons per ...