Question

The typical mutation frequency determined for φ-T2 resistance (φ-T2R) is between 10^-7 and 10^-8 The coding region of ompF is 1,089 bp and the chromosome of the E. coli strain we used is 4,639,675 bp long. Does the 10^-3 mutations/base/generation fmut calculated byLee et al. (2012) match what is found experimentally? (ignore that there were multiple generations of cells)

Answer 1

1. The ompF encodes for the outer membrane protein F which is well characterized for perforation and entry of viral genome into cells of E.coli.
2. It is around 1089bp long. The E.coli chromosome is around 46,39,675 bp long. But, only the coding sequences contributes to the transfection.
3. We should consider the type of mutation associated. In case of studies of Lee.et.al it was mainly concerned with MMR sites and their impacts on mutation rate with respect to ratios of G:C and A:T.
4. In this case, the mutation frequency (f-mut) is ranging from 10^-7 to 10^-8 which is not similar to the frequency in the MMr strains as calculated by Lee.et.al.
5. Besides, intergenic mutation rates are stated to have equal frequencies with respect to that of the phage mutation rates. So, this states that they should be in the range of the E.coli frequency. But, considering the situation mentioned in the above case, the frequency calculated above indicates the mutation in terms of φ- T2 resistance. This may be associated with the activity of the perforating toxins as OMP-F has been mentioned in association.
6. Multiple generation needs to be ignored because major changes are not expected but for transfection to occur.
7. Accordingto 95% Poisson's Cls , the new research states similarity on the basis of finding region overlaps to be a significant information in dealing with transfection. The mutation frequency in terms of spectrum mentioned above does not indicate similar relation with the intergenic frequency thereby neglecting the match.
8. To add a point for the coding regions in E.coli, they typically mark presence of more than 600 coding regions and hence overlaps recognition marks similarity but C:G ratio with respect to A:T must be considered for transfection which in turn indicates association with the mutation frequency.