Molecular Biology of Malaria and Opportunistic Parasites Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
Infect Genet Evol. 2009 Dec;9(6):1295-300. doi: 10.1016/j.meegid.2009.07.005. Epub 2009 Jul 28.
Apical membrane antigen-1 is a candidate for inclusion in a vaccine for the human malaria parasite Plasmodium vivax. We collected 231 complete sequences of the gene encoding this antigen (pvama-1) from three regions of Thailand, the most extensive collection to date of sequences at this locus. The domain II loop (previously mentioned as a potential vaccine component) was almost completely conserved, with a single amino acid variant (I313R) observed in a single sequence. The 3' portion of the gene (domain II through the stop codon) showed significantly lower nucleotide diversity than the 5' portion (start codon through domain I); and a given domain I sequence might be found in a haplotype with more than one domain II sequence. These results imply a hotspot of recombination between domains I and II. We found significant geographic subdivision among the three regions of Thailand (NW, East, and South) in which collections were made in 2007. Numbers of P. vivax infections have experienced overall declines since 1990 in all three regions; but the decline has been most recent in the NW, and there has been a rebound in numbers of infections in the South since 2000. Consistent with population history, amino acid sequence diversity was greatest in the NW. The South, which had by far the lowest sequence diversity of the three regions, showed signs of a population that has expanded from a small number of founders after a bottleneck.
顶膜蛋白抗原-1 是人类疟原虫恶性疟原虫疫苗候选抗原。我们从泰国的三个地区收集了 231 个编码这种抗原（pvama-1）的基因完整序列，这是目前该基因座序列的最大收集。结构域 II 环（先前提到的潜在疫苗成分）几乎完全保守，在单个序列中观察到一个单一的氨基酸变体（I313R）。基因的 3'部分（结构域 II 至终止密码子）的核苷酸多样性明显低于 5'部分（起始密码子至结构域 I）；并且给定的结构域 I 序列可能存在于具有多个结构域 II 序列的单倍型中。这些结果表明结构域 I 和 II 之间存在重组热点。我们发现 2007 年采集的泰国三个地区（西北、东部和南部）之间存在显著的地理细分。自 1990 年以来，所有三个地区的间日疟原虫感染人数都经历了总体下降；但西北地区的下降最为明显，自 2000 年以来，南部地区的感染人数有所反弹。与种群历史一致，氨基酸序列多样性在西北地区最大。南部地区是三个地区中序列多样性最低的地区，显示出种群从瓶颈期少数创始人扩张而来的迹象。
