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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." [11] [12] 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 ...
Plant transformation vectors are plasmids that have been specifically designed to facilitate the generation of transgenic plants.The most commonly used plant transformation vectors are T-DNA binary vectors and are often replicated in both E. coli, a common lab bacterium, and Agrobacterium tumefaciens, a plant-virulent bacterium used to insert the recombinant DNA into plants.
conjugative - mediate DNA transfer through conjugation and therefore spread rapidly among the bacterial cells of a population; e.g., F plasmid, many R and some col plasmids. nonconjugative - do not mediate DNA through conjugation, e.g., many R and col plasmids. The pBR322 plasmid is one of the first plasmids widely used as a cloning vector.
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.
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 ...
These genes code for a series of proteins that cut the binary vector at the left and right border sequences, and facilitate transfer and integration of T-DNA to the plant's cells and genomes, respectively. [4] Several vir helper plasmids have been reported, [12] and common Agrobacterium strains that include vir helper plasmids are: EHA101 ...
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.
The role of a plasmid in this pathogenic ability was further supported when large plasmids were found only in pathogenic bacteria but not avirulent bacteria. [11] Eventually, the detection of parts of bacterial plasmids in host plant cells was established, confirming that this was the genetic material responsible for the genetic effect of ...