Microbiology (2010), 156, part 3, 950–959.
The following changes have been made to the online version of the above paper.
1. Introduction, page 951, first column, line 2
The citations on this line have been replaced with ‘Hove-Jensen, 1985; Post et al., 1991’.
2. Methods, page 951, second column, line 18, ‘Spontaneous mutations...∼4×108’., replace with:
‘Spontaneous mutations allowing growth arose at a frequency of ∼4×10−8’.
3. Results, page 953, second column, line 4, beginning with ‘The addition of...’, replace with:
‘The addition of 0.2 % vitamin-free Casamino acids to the medium resulted in colonies arising at a frequency of ∼4×10−8. The component of the Casamino acids which allowed thiamine-independent revertants to arise was methionine’.
4. Table 2, page 953
In Table 2, allele prsA503 has a change of ‘G–12T’ and not ‘G12T’.
5. Discussion, page 958, first column, line 27, beginning ‘Additionally...’, replace with:
‘Additionally, this study is a new report of a positive selection for mutations that negatively affect the enzymic activity of PrsA’.
6. References
(a) The following reference has been added to the References list:
Hove-Jensen, B. (1985). Cloning and characterization of the prs gene encoding phosphoribosylpyrophosphate synthetase of Escherichia coli. Mol Gen Genet 201, 269–276.
(b) The following reference has been deleted from the References list:
Larsen et al., 1999.