PCR and restriction analysis of pNIK. (A) Digestion of pLXP, cosG4 and pNIK with Eco RI, Bam HI and Kpn I. pNIK contained the same restriction fragments with pLXP and cosG4 and generated some new ones. M, 1 kb molecular marker; lane 1, 4 and 7, pLXP; lane 2, 5 and 8, cosG4; lane 3, 6 and 9, pNIK. (B) PCR analysis of pLXP, cosG4 and pNIK. pNIK contained all three genes tested. Primers sanP+, sanP-, sanX+, sanX-, sanF+ and sanF- were used to amplify a 400 bp, 220 bp and 120 bp DNA fragment of sanP, sanX and sanF using pLXP, cosG4 and pNIK as template. M, 100 bp molecular marker, lane 1, 4 and 7, cosG4; lane 2, 5 and 8, pLXP; lane 3, 6 and 9, pNIK.