Table 2.

Reverse transcription quantitative polymerase chain reaction (RT-qPCR) analysis of the nitrogen-regulated gene expression in Anabaena 7120 in the absence (control) or in the presence of BMAA (20 μM) after 4, 8, 24, 48 and 96 h of BMAA treatment in nitrate-containing medium ¹.

Gene	Product		Relative Ratio in log2
			4 h	8 h	24 h	48 h	96 h
hetR	HetR, Heterocyst differentiation protein	Control	−2.33 ± 0.02	0.64 ± 0.23	−1.03 ± 0.19	0.09 ± 0.07	0.15 ± 0.06
		BMAA	−2.26 ± 0.32	0.45 ± 0.41	−1.29 ± 0.22	3.35 ± 0.38	0.36 ± 0.22
hepA	HepA, Heterocyst differentiation protein	Control	−0.53 ± 0.06	0.66 ± 0.21	−0.06 ± 0.13	0.09 ± 0.07	0.15 ± 0.06
		BMAA	1.35 ± 0.05	3.87 ± 0.36	1.83 ± 0.23	3.35 ± 0.38	0.36 ± 0.22
ntcA	NtcA, Nitrogen-responsive regulatory protein	Control	−2.01 ± 0.01	2.50 ± 0.60	−1.35 ± 0.11	−0.12 ± 0.09	−0.65 ± 0.27
		BMAA	−1.36 ± 0.67	2.30 ± 0.35	−0.53 ± 0.10	1.31 ± 0.27	0.88 ± 0.22
nifH	Nitrogenase subunit	Control	−0.39 ± 0.07	1.37 ± 0.63	1.47 ± 0.68	0.30 ± 0.50	3.18 ± 2.82
		BMAA	0.50 ± 0.08	3.44 ± 0.11	2.62 ± 0.07	6.57 ± 1.43	4.82 ± 0.58
glnA	Glutamine synthetase	Control	1.51 ± 0.56	−0.56 ± 0.05	2.22 ± 0.95	0.19 ± 0.16	−2.60 ± 0.17
		BMAA	1.80 ± 0.04	−0.67 ± 0.99	2.17 ± 0.67	2.70 ± 0.15	1.02 ± 0.11
gltS	Glutamine-oxoglutarate-aminotransferase	Control	−1.66 ± 0.58	1.23 ± 0.15	−1.14 ± 0.40	−0.24 ± 0.03	0.65 ± 0.17
		BMAA	−1.95 ± 0.39	0.67 ± 0.28	−0.13 ± 0.01	2.17 ± 0.16	2.17 ± 0.12
nirA	Nitrite reductase	Control	−0.65 ± 0.16	1.40 ± 0.16	−0.67 ± 0.26	−1.51 ± 0.16	−4.54 ± 0.07
		BMAA	−1.10 ± 0.28	1.63 ± 0.19	−0.90 ± 0.26	−1.18 ± 0.18	−2.87 ± 0.15

¹ Fold changes in gene expression are reported as log₂ values. Each sample was measured in triplicate, and the standard deviation is indicated by error bars. Values were normalized to the rnpB transcript level. The expression of the “housekeeping” gene rnpB was not affected by the action of BMAA (data not shown). Significant differences of transcript levels between control and treated samples are shown inbold (p < 0.05) and were tested by Student’s t-test.