Categories:Pages edited by students of Prof. McDevitt Classification
Domain: Bacteria Phylum: Protobacteria Class: Gammaproteobacteria Order: Enterobacteriales Family:Enterobacteriaceae Genus: Escherichia Species: Escherishia coli DH5-Alpha (1)
Description and significance
This strain of E. Coli is not a pathogen, and was developed for laboratory cloning use. This strain was developed by D. Hanahan as a cloning strain with multiple mutations that enable high-efficiency transformations (2). The mutations that the DH5-Alpha strain has are: dlacZ Delta M15 Delta(lacZYA-argF) U169 recA1 endA1 hsdR17(rK-mK+) supE44 thi-1 gyrA96 relA1 (2). These mutations correspond to the distinct characteristics that make the DH5-Alpha strain excel in laboratory cloning procedures (2).
lacZ Delta M15 mutation: Allows for blue-white screening for recombinant cells. (3) endA1 mutation: Allows for lower endonuclease degradation which ensures higher plasmid transfer rates. (4) recA1 mutation: reduces homologous recombination for a more stable insert. (5)
The genomic structure of this strain is a singular circular chromosome consisting of 4,686,137 nucleotides, 4359 genes, and 4128 protein encoding genes (6)
This strain also contains plasmids, and has the ability to accept plasmid insertion exceptionally well.
Cell structure, metabolism & life cycle
E. coli are gram-negative bacillus bacteria. They reproduce by successive binary fission with a generation time of approximately 30 minutes with optimum growth occurring at 37 degrees centigrade. E. coli are facilitative aerobic bacteria and are capable of ATP synthesis via both aerobic respiration and, if oxygen is not present, fermentation. This particular strain can be identified and distinguished from other E. coli strains, by examining the genetic sequence of its 16s small ribosomal subunit, which has been fully sequenced (7).
This strain of E. coli was developed in the laboratory, for laboratory cloning procedures, and therefor has no 'natural' environment or habitat as it does not exist in nature.
This specific strain of E. coli has been, in recent studies, used for computational data storage. Researchers have been able to readily insert plasmids into the cell that contain computational data, encrypted using a quaternary coding language that makes use of the four nucleotide base pairs, into the cell and have it be self replicating (8). This allows for excessive amounts of data storage, upwards of 900,000 gigabytes in a single gram of bacteria (9). The research team, based in Hong Kong, have developed a computer program that corresponds with this research that allows users to 'simply' type, in regular text, what they would like to encode in the cell, and instantly have it translated into the biological code, which is then ready to be inserted into the cell (8).
(2) Taylor, R. G., Walker, D. C. and McInnes, R. R. ( 1993). E. coli host strains significantly affect the quality of small scale plasmid DNA preparations used for sequencing. Nucleic Acids Res. 21, 1677 -1678.
(7) Singh, Om V. ., and Steven P. . Harvey. "Bacterial Communities." Sustainable Biotechnology. Dordrecht [etc.: Springer, 2010. 169-71. Print.