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  • Rights: The University of Waikato Te Whare Wānanga o Waikato
    Published 3 February 2022 Referencing Hub media

    E. coli is a useful organism. It is used in laboratories across the world for many different purposes. Dr Adele Williamson from The University of Waikato explains why E. coli is such an important tool for science.

    Find out about Dr Adele Williamson’s research to find new tools for molecular biology:


    Dr Adele Williamson

    E. coli is a bacterium which we know of as living in our intestine. We think of it as being maybe a nasty poo bacteria. But the reason that scientists are really enthusiastic about E. coli is that it’s a model bacterium. It’s one of our favourite laboratory pets if you will. We’re really, really good at growing it, and we’re very good at being able to change it to make it do what we want it to.

    There’s a lot of different strains of E. coli where we’ve taken out genes that we don’t want to have – for example, genes which chew up proteins, genes which recombine bits of DNA, because if we have this is a host organism, we don’t want it chewing up the proteins that we’ve made. We don’t want it switching around the bits of DNA that we’ve put into it. And we’ve also learned how to trick E. coli into making a whole lot of the protein that we want to produce.

    Because we’ve characterised E. coli really well, we can put a new bit of DNA into it, onto a small extra circle of DNA called a plasmid – we pop our gene in there. And then because we understand the metabolic machinery of E. coli really well, we know if we place that circle of DNA in a particular chemical, we can tell E. coli to switch on to producing a lot of that protein and then we can get a lot of our target protein out of E. coli.

    One example is recombinantly produced insulin, which is the protein that diabetics ingest. We used to get this from pig pancreases purified directly from the animal, and this obviously has a few problems that you’re limited by how much material you can get and also problems with disease transmission for example. So by being able to recombinantly produce insulin then, this has secured the supply of insulin for diabetics all over the world and has just meant that you can produce a lot more of this a lot easier.


    Dr Adele Williamson, The University of Waikato
    Micrograph of E. coli,NIAID. CC BY 2.0
    Pig and piglets and pig pancreases, Living Cell Technologies Ltd

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