Is it possible to identify E.coli strains using PCR-based methods? How does the identification of E.coli strains work? Is it based on 16srRNA and phylogeny study or ...?
Hello you can use one of above ways.
1.Perform colony per with primers binding to the T7 polymerase gene. If you get a band of the expected size, you have the DH5a strain.
2. If you have one available, transform the strain with a plasmid containing an easily detectable gene (GFP, betagal etc.) under the control of the T7 promoter. If the gene expresses, you have the DH5a strain.
Hello you can use one of above ways.
1.Perform colony per with primers binding to the T7 polymerase gene. If you get a band of the expected size, you have the DH5a strain.
2. If you have one available, transform the strain with a plasmid containing an easily detectable gene (GFP, betagal etc.) under the control of the T7 promoter. If the gene expresses, you have the DH5a strain.
Hi Myryam,
16srRNA won't be useful here as we talk about different strains/genotypes of the same species. As for the suggested PCR for the T7 polymerase gene this depends if you want to test for BL21 or BL21(DE3). Please see below for details about E.coli genotypes. The colony morphology of the two strains differs, DH5a is round and compact whereas BL21 tends to be flat and less symmetric.
If you have doubts about the genotype of your E.coli it is best to get it from a reliable source and not waste your time in testing for particular genes. There are many differences and variations.
DH5a is a general purpose strain for cloning. BL21 and derivatives are used for expression. Remember that you need to use BL21(DE3) if you want to express your gene of interest from a T7 promotor.
br Markus
https://openwetware.org/wiki/E._coli_genotypes
https://www.neb.com/tools-and-resources/usage-guidelines/additional-e-coli-strain-genotypes
As Myryam suggested 16srRNA won't be useful to differentiate between Dh5alpha versus BL21.
As BL21 codes for T7RNA polymerase, whereas DH5alpha carries T5RNA polymerase. Therefore, you can run simple PCR using T7 RNA polymerase specific primers to differentiate both strains. PCR positive indictaes you have BL21.
This link will be helpful.
https://www.thermofisher.com/in/en/home/life-science/cloning/cloning-learning-center/invitrogen-school-of-molecular-biology/molecular-cloning/transformation/competent-cell-genotypes-genetic-markers.html
- Badges
- Science topic
- Similar topics
- Biological Science
- Molecular Cell Biology