TABLE 1.
Characteristics of the strains studieda
| Strain | Relevant genotype | Mutant name(s) | Growth | Pyrimidine excretion (μg/ml) | Comments or reference |
|---|---|---|---|---|---|
| Wild-type CCM 1904 | Prototroph | 0 | |||
| CCM 1904 mutants | ΔpyrD | PH1021 | Ura− | Not tested | 9 |
| aat2 (G1356A) | AE1021 | Prototroph | 5.7 | aat2 hexaloop mutated | |
| at2b | AE1023 | HCR | 0 | Unstable RNA at2 loop | |
| pyrR1 (G1090T) | AE1026 | Prototroph | 4.3 | PyrR1 D104Y | |
| ΔcarAB | FB335 | Uras prototroph | 0 | 19 | |
| Pyrimidine-deregulated isolates of FB335c | |||||
| RNA loops | ΔcarAB aat2 (Δ1332-1349) | U1, U8, U28 | Prototroph | 7.3 | aat2 loop absent |
| ΔcarAB aat2 (G1358A) | U4 | HCR | 2.5 | aat2 hexaloop mutated | |
| ΔcarAB aat2-at2 (G1360A) | U23 | Prototroph | 6.7 | aat2 loop mutated | |
| ΔcarAB ΔpyrR1 aat2 (Δ886-1340) | U25 | Prototroph | 14.7 | G36 to E180 PyrR1 deletion and aat2 loss | |
| ΔcarAB aat2 (G1361T) | U26 | Prototroph | 3.1 | aat2 loop mutated | |
| ΔcarAB at2 (T1401G) | U33 | HCR | 0 | at2 loop mutated | |
| PyrR1 | ΔcarAB pyrR1 (C1204T) | U3 | Prototroph | 4.6 | PyrR1 P124S |
| ΔcarAB pyrR1 (G901A) | U5 | Prototroph | 4.0 | PyrR1 G41R | |
| ΔcarAB pyrR1 (G1140) | U6 | Prototroph | 0.4 | PyrR1 M120I | |
| ΔcarAB pyrR1 (C991T) | U9 | Prototroph | 1.8 | PyrR1 R71W | |
| ΔcarAB ΔpyrR1 (1228-1296) | U12 | Prototroph | 4.6 | H170-G172 PyrR1 deletion | |
| ΔcarAB pyrR1 (A1193G) | U13 | Prototroph | 2.3 | PyrR1 H138R | |
| ΔcarAB pyrR1 (G1282T) | U15 | Prototroph | 2.4 | PyrR1 D168N | |
| ΔcarAB pyrR1 (C1195T) | U16 | Prototroph | 1.9 | PyrR1 R139C | |
| ΔcarAB ΔpyrR1 (769-1041) | U17 | Prototroph | 8.5 | No PyrR1 translated | |
| ΔcarAB pyrR1 (1141 insG) | U18 | Prototroph | 8.6 | D121-E180 PyrR1 deletion | |
| ΔcarAB pyrR1 (911insT) | U19 | Prototroph | 7.6 | F44-E180 PyrR1 deletion | |
| ΔcarAB pyrR1 (G997A) | U22, U29 | Prototroph | 1.2 | PyrR1 D73N | |
| ΔcarAB pyrR1 (924insA) | U24 | Prototroph | 7.7 | A49-E180 PyrR1 deletion | |
| ΔcarAB ΔpyrR1 (795-950) | U31 | HCR | 6.2 | V6-G57 PyrR1 deletion | |
| ΔcarAB pyrR1 (ins801)d | U32 | Prototroph | 7.6 | Q17-E180 PyrR1 deletion | |
| ΔcarAB pyrR1 (G783A) | U40 | HCR | 7.2 | PyrR1 truncated due to a point mutation in the initiation codon | |
| ΔcarAB pyrR1 (C1117T) | U41 | Prototroph | 5.4 | PyrR1 R113W |
Sequence data refer to EMBL accession number Z54240. Prototrophs grew without arginine and uracil in defined medium DLA. The growth of uracil-sensitive (Uras) prototrophs was inhibited by uracil in the absence of arginine. The high-carbon-dioxide-requiring (HCR) auxotrophs require exogenous arginine and uracil at low carbon dioxide levels (see Table 3).
TgTgaggaacTTaacggAtACCAGT; mutated bases in uppercase (nucleotides 1355 to 1379 in database accession no. Z54240).
Uracil-resistant (Urar) derivatives of strain FB335 that acquired the ability to grow in the presence of uracil when arginine was omitted from DLA plates incubated in CO2-enriched air.
The inserted sequence is 5′-GCAATGACCATGCGCCGCGCGCTGAC-3′.