K-12菌株 BioVector NTCC质粒载体菌种细胞基因保藏中心

K-12菌株

E. coli K-12 wildtypeis derived from a strain in the collection of the what was then the Departmentof Bacteriology at Stanford University. In 1944, Gray and Tatum^[1]reported theisolation of a biotin auxotroph and a threonine auxotroph after X-raymutagenesis ofE. coliK-12. The parentalstrain is described in the acknowledgements as having been obtained from Dr.C.E.Clifton at Stanford. Elsewhere, Tatum and Lederberg describe the strain ashaving been used in student labs at Stanford for several years^[2].

The original K-12strain was F⁺and lysogenic forphage lambda.

Different stocks ofthe original K-12 strain were obtained by different labs at different times.The Coli Genetics Stock Center has two isolates ofE. coliK-12 wildtype:WG1andEMG2.WG1was obtained from J.Lederberg andEMG2was obtained fromClowes and Hayes. The stock center isolate ofEMG2is described ashaving no mutations, while the isolate ofWG1available from CGSChas anrfbBdeletion and carriesF1-1, a shortened variant of F. See Bachmann (1996) for a more detailed historyof these strains.^[3]

References

1. ↑ Gray,     CH & Tatum, EL (1944) X-Ray Induced Growth Factor Requirements in     Bacteria. Proc. Natl. Acad. Sci. U.S.A. 30 404-10 PubMedEcoliWiki page

2. ↑ Tatum,     EL & Lederberg, J (1947) Gene Recombination in the Bacterium     Escherichia coli. J. Bacteriol. 53 673-84 PubMedEcoliWiki page

3. ↑ Bachmann,     B.J. Derivations and genotypes of some mutant derivatives of Escherichia     coli K-12. In: Neidhardt, FC et al. (1996) Escherichia     coli and Salmonella typhimurium: Cellular and     Molecular Biology (ASM Press, Washington, DC)

Recovery

1. Obtain an LB agar plate     with the appropriate antibiotic.

2. Using a sterile pipette     tip, touch the bacteria growing within the punctured area of the stab     culture. (A sterilized wire loop or sterile toothpick can be used in place     of a sterile pipette tip.)

3. Run this tip lightly over     a section of the plate, as shown in the figure, to create streak #1.

4. Using another sterile     pipette tip, pass through streak #1 and spread the bacteria over a second     section of the plate, to create streak #2.

5. Using a third sterile     pipette tip, pass through streak #2 and spread the bacteria over the last     section of the plate, to create streak #3.

6. Grow overnight in a 37 ^o     C incubator (unless a different growth temperature is indicated on the     plasmid datasheet).

7. In the morning, single     colonies should be visible. If the bacterial growth is too dense,     re-streak onto a new agar plate to obtain single colonies.

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