. 2008 Mar 31;74(11):3471–3480. doi: 10.1128/AEM.02694-07

TABLE 2.

Detection of nitrogenase genes in the environmental isolates using PCR and Southern hybridization

Isolate	DNA fragment size(s) (kb)^a
Isolate	nifD/nifH	vnfD/vnfG	anfD/anfG
AN1	+	ND	3.1
ARB2	15	4.4, 5.0	ND
ARB3	12	2.3, 4.3	ND
BR2	1.4	+	+
BR3	1.5	+	+
BR5	1.4	+	+
BR6	1.5	+	+
BR7	1.4	+	+
BR8	1.5	+	+
BR10	+	+	+
DP6	9	+	+
DP7	8	+	+
LPF4	+	+	+
MB4	+	1.7, 4.5	ND
MU1	>10	5.0, 4.5	ND
MU2	>10	5.0, 4.5	ND
MU4	4.4, 1.4	4.9, 3.0, 1.3	6.2, 3.4
MU5	1.4	3.0, 1.3	3.4
MU6	1.5	+	ND
MU7	1.4	3.0, 1.3	3.4
MU11	1.4	+	+
MU12	1.4	+	+
MU13	1.7	+	+
NC2	7.1	+	+
PB3	>10	2.2	ND
PRM1	7.8	2	>10

DNA fragment size(s) in EcoRI digests of genomic DNAs hybridizing to nitrogenase gene probes listed in references 7, 26, and 41. +, products cloned and sequenced using primers listed in references 27, 28, 34, and 54; ND, not detected.