Question

In this experiment, you are measuring mutation frequency. How could you redesign the experiment to determine the mutation rate to azide resistance for E. coli? Explain

Answer 1

Mutations bestowing resistance to azide in Escherichia coli take place principally in the secA gene.

Mutant strains of Escherichia coli were monitored for the capability to cultivate on Luria Agar (LA) plates enclosing 3.4 or 4.6 mM sodium azide. The majority of mutants had mutations positioned in the leucine region, apparently at the azi locus. Literature review revealed that two of these mutants were found to have a mutation in the secA gene, but appearance of the resistance phenotype also need the existence of upstream gene X. Although a plasmid carrying the X-secA mutant gene pair was competent to confer azide resistance to a susceptible host, a comparable plasmid harboring the wild-type secA allele provided a resistant strain sensitive to azide, demonstrating codominance of the two alleles. That azide hinders SecA is unfailing with the verity that SecA has ATPase activity, an activity that is repeatedly prone to inhibition by azide