[Preliminary study on the surface antigen gene of Plasmodium malariae]

The genomic Hind III lambda gt1149 library from Plasmodium malariae was screened with two types of oligonucleotides, both of which were from the P190 gene of P. falciparum. One, MAD20 type, was made from spanning nucleotides 4488-4562 in the P190 gene of MAD20 strain and another, K1 type, was made from spanning nucleotides 3652-3692 in the P190 of K1 strain. Both were end-labelled with 32P-ATP as probes before hybridization. Two clones were selected. One clone, designated lambda MSA-1, was specifically recognized by the MAD20 type oligo probe; the other, designated lambda MSA-2, by the K1 type oligo probe. lambda MSA-1 and lambda MSA-2 inserts were obtained by Hind III digestion of the two clone phage DNA. The analysis of the two inserts showed that the size of lambda MSA-1 is 5.5 kb whilst that of lambda MSA-2 is 3.5kb. The MSA-1 and MSA-2 inserts recloned into PUC8 were digested with the restriction enzymes Bg1 II, EcoR I, Xba I, Hind II and Pst I. The results showed that the MSA-1 DNA had one Bg1 II site, one EcoR I site, two Xba I sites, one Hind II site and one Pst I site. The MSA-2 DNA had only one Hind II site. The surface antigen gene of P. malariae was little known. This result also showed that there was probably an analogue of P190 on the surface of P. malariae, and they might fall into two types. This study is informative for further investigation on malariae parasites.