Table 2.
Results of the main bacterial reverse mutation test of GT using the preincubation method
| Concentration (µg TOS/plate) | Revertant colonies per plate (mean ± SD) | ||
|---|---|---|---|
| Escherichia coli WP2uvrA | Salmonella typhimurium TA1537 | ||
| −S9 | +S9 | +S9 | |
| Negative control (distilled water)a | 28 ± 4 | 25 ± 3 | 14 ± 1 |
| 25.1 | 24 ± 3 | 28 ± 4 | – |
| 50.2 | 29 ± 5 | 26 ± 2 | – |
| 100 | 24 ± 3 | 26 ± 6 | – |
| 201 | 30 ± 2 | 31 ± 5 | – |
| 402 | 26 ± 5 | 31 ± 5 | 14 ± 3 |
| 803 | 26 ± 4 | 24 ± 3d | 15 ± 5e |
| 1,610 | 28 ± 4d, e | 30 ± 3d, e | 18 ± 0e |
| 3,210 | 29 ± 4d, e | 28 ± 2d, e | 16 ± 3e |
| 6,430 | – | – | 18 ± 4e |
| 12,850 | – | – | 35 ± 5e |
| Positive controlb, c | 125 ± 6 | 994 ± 142 | 179 ± 34 |
Abbreviations: –, not applicable; −S9, in the absence of S9; +S9, in the presence of S9; 2‐AA, 2‐aminoanthracene; AF‐2, 2‐(2‐furyl)‐3‐(5‐nitro‐2‐furyl) acrylamide; GT, glutaminase from nongenetically modified A. niger strain GT147; SD, standard deviation; TOS, total organic solids.
a
100 µl/plate.
b
Positive control −S9: WP2uvrA = 0.01 µg/plate AF‐2.
c
Positive control + S9: TA1537 = 2.0 µg/plate 2‐AA; WP2uvrA = 10 µg/plate 2‐AA.
d
Growth inhibition was observed.
e
The growth of background lawn of bacteria was accelerated, and the plates looked turbid.