Practical Applications
Increasing the frequency of desired transformation:
Insulin was first biosynthesized by transforming a recombinant plasmid into E. coli. Today, E. coli transformation is not only used to create transgenic bacteria, but is also a common biotechnological practice used to replicate plasmid DNA.33 As transformants divide, acquired plasmid DNA is replicated such that each daughter cell retains a copy. A greater understanding of the mechanism of transformation and the conditions required for maximum transformation frequency could allow transformation frequency to be increased, increasing plasmid yield. The pH of solutions used in E. coli competence development and transformation may be buffered to the ideal level. Alternatively, protonophores or ionophores could be added to these solutions to simulate the effects of ideal extracellular pH on the cell membrane.
Reducing the frequency of undesired transformation:
A concern with the introduction of transgenic plants is the risk of transfer of antibiotic resistance genes to bacteria in the soil. The frequency of natural transformation has been estimated as extremely low, one in 1016 to 1017 bacteria. However, based on this frequency and estimates that 5 x 1028 bacteria exist per 1.4 x 1013 m2 of topsoil, one transformant would be found in every 25m2 of topsoil. Thus, over a trillion transformants would occur over the nearly 70 million hectares currently planted with transgenic crops. The frequency of natural transformation could be reduced by growing transgenic plants in soils of a pH less favourable to transformation, or altering the pH of greenhouse soil to be less transformation favourable. Although these experiments can suggest at what approximate pH the risk of transformation in the soil would be greatest, further experiments should be done using naturally transformable bacteria and chromosomal DNA in a soil microcosm.
In clinical settings:
Antigenic types of E. coli are responsible for urinary tract infections, neonatal meningitis, and intestinal diseases (gastroenteritis). Human intestinal pathogens such as Salmonella, Shigella, and Yersinia are in the same family as E. coli. Parallels have recently been found been antibiotic resistance in soil bacteria and infected patients. Antibiotic resistance of E.coli in clinical settings and infected patients could be reduced by a better understanding of the optimal conditions, driving forces and mechanism of transformation.
