genetically engineered a group has constructed a mutant Escherichia coli in the biosensor system that triggers the movement of the flagellum.
If inoculated wild type, call-1 strain in semisolid agar the bacteria can "Swim" and spread around:
wild strain:
(*) click on image to view larger
In the mutant strain, called strain-2, has the deleted gene chez encoding the protein Chez. Without this protein the flagellum movement control is lost.
First question: How do you behave the mutant? Does semisolid agar diffusion will be higher or lower than in the wild strain?
A the research team then takes the strain lacking Chez and I introduced a plasmid containing the gene for this protein, but under the control of a ribointerruptor (riboswitch) . This new strain is called strain-3.
The ribointerruptor works as follows:
- In the absence of a molecule, let's call it molecule A, the gene messenger mRNA chez can not be translated by ribosomes.
- In the presence of the molecule A, the mRNA of the gene chez can be translated by ribosomes.
Researchers Strain-3 inoculated in a semisolid agar plate where it has added a drop containing the molecule A in one side of the plate.
Second question: How will behave Strain-3 at the plate? Do or get closer to the molecule A?
This research group also introduced the gene for Green Fluorescent Protein or GFP ( F G reen luorescent P rotein ) in the strain-3, thus the strain-4. This bacterium emits green fluorescence by the protein
Third question: What practical use could be strain-4?
(*) Figure produced from the book " Brock. Biology of microorganisms " Pearson Publishing
