Analysis of transfected D10-ΔMSP1#2 parasite populations at different time points. (A) PFGE separating chromosomes
from parental D10 (lane 1) and transfected parasite populations
of D10-ΔMSP1#2 after no (lane
2) or one to three cycles in culture (lanes 3–5). Following
transfer to a nitrocellulose membrane, the filter was hybridised
with the 900 bp MSP-1 probe. Chromosome 9, the location of the endogenous MSP-1 gene, is indicated (chr9). (B) PFGE separating chromosomes from parental D10 (lane 1) and transfected
parasite populations of D10-ΔMSP1#2
after no and two drug cycles either on drug selection (lanes 2 and 4,
respectively) or maintained in the absence of pyrimethamine selection
for 5 weeks (lanes 3 and 5, respectively). Southern blotting and
hybridisation was as described in (A).