Table 1.

Results of concentration‐finding bacterial reverse mutation test of GT using preincubation method

Concentration (µg TOS/plate)	Revertant colonies per plate (mean ± SD)
	Salmonella typhimurium								Escherichia coli
	TA100		TA1535		TA98		TA1537		WP2uvrA
	−S9	+S9	−S9	+S9	−S9	+S9	−S9	+S9	−S9	+S9
Negative control (distilled water)a	117 ± 7	120 ± 5	13 ± 1	13 ± 1	24 ± 6	26 ± 2	10 ± 3	14 ± 1	29 ± 3	21 ± 4
1.96	–	–	–	–	–	–	–	–	24 ± 3	20 ± 1
5.88	–	–	–	–	–	–	–	–	22 ± 3	22 ± 2
17.6	–	–	–	–	–	–	–	–	21 ± 5	23 ± 4
52.9	110 ± 8	125 ± 10	8 ± 2	11 ± 3	26 ± 4	30 ± 3	11 ± 3	19 ± 3	23 ± 3	22 ± 2
159	124 ± 8	121 ± 9	11 ± 2	11 ± 2	24 ± 3	34 ± 3	12 ± 3	19 ± 5	27 ± 2	26 ± 2
476	130 ± 4	141 ± 6	14 ± 2	10 ± 2	28 ± 3	33 ± 3	10 ± 2	13 ± 2	25 ± 3	23 ± 1
1,430	143 ± 9	140 ± 15	15 ± 3	10 ± 1	32 ± 6	46 ± 6d	11 ± 2d	23 ± 2d	24 ± 2e	21 ± 3d, e
4,280	182 ± 4d	215 ± 10d	22 ± 2d	24 ± 3d	41 ± 5d	66 ± 12d	9 ± 3 d	20 ± 3d	34 ± 2d, e	24 ± 4d, e
12,850	291 ± 24d	296 ± 37d	33 ± 6d	35 ± 3d	77 ± 3d	95 ± 21d	22 ± 3d	21 ± 4d	–	–
Positive controlb, c	637 ± 32	785 ± 25	552 ± 27	323 ± 13	704 ± 31	357 ± 14	200 ± 5	186 ± 16	105 ± 11	716 ± 31

Abbreviations: −S9, in the absence of S9; +S9, in the presence of S9; 2‐AA, 2‐aminoanthracene; 9‐AA, 9‐aminoacridine hydrochloride; AF‐2, 2‐(2‐furyl)‐3‐(5‐nitro‐2‐furyl) acrylamide; GT, glutaminase from nongenetically modified A. niger strain GT147; NaN_3, sodium azide; SD, standard deviation; TOS, total organic solids.

^a100 µl/plate.

^bPositive control −S9: TA100 and WP2uvrA = 0.01 µg/plate AF‐2; TA1535 = 0.5 µg/plate NaN₃; TA98 = 0.1 µg/plate AF‐2; TA1537 = 80 µg/plate 9‐AA.

^cPositive control + S9: TA100 = 1.0 µg/plate 2‐AA; TA1535 and TA1537 = 2.0 µg/plate 2‐AA; TA98 = 0.5 µg/plate 2‐AA; WP2uvrA = 10 µg/plate 2‐AA.

^dThe growth of background lawn of bacteria was accelerated, and the plates looked turbid.

^eGrowth inhibition was observed.