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Molecular approaches to the genetic diversity of malaria parasites

疟疾寄生虫遗传多样性的分子方法

基本信息

批准号：
11694323
负责人：
TANABE Kazuyuki
金额：
$ 7.23万
依托单位：
Osaka Institute of Tecnology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11694323/
关键词：
Malaria Plasmodium Gene Antigen MSP1 PGR Recombination Polymorphism 多様性オーシスト

项目摘要

The genetic diversity of surface antigens of malaria parasites was studied on field isolates from geographic endemic areas. Analysis of about 500 isolates by PCR and DNA sequencing revealed the followings.1. Polymorphism of the merozoite surface antigen gene (PfMsp-1) of P. falciparum: Linkage disequilibrium between polymorphic sites in the 5'-region (blocks 2-6) and 3'-region (block 17) of PfMsp-1 in parasite population from Thailand, Vietnam and Brazil The strength of this linkage disequilibrium correlated with the intensity of transmission of malaria. It is suggested that both selection and genetic drift are involved in this linkage disequilibrium. The diversity of PfMsp-1 was very limited in Vanuatu with very strong linkage disequilibrium between the 5'- and 3' - polymorphic sites. Extremely low rate of mixed clone infections in Vanuatu suggests that the rate of recombination in PfMsp-1 depends on not only the intensity of transmission but the frequency of mixed infection and the number of alleles present in an endemic area.2. Polymorphism of the merozoite surface antigen gene (PvMsp-1) of P. vivax: In order to examine in-depth structural organization of PvMsp-1 , complete nucleotide sequencing of the gene of 40 isolates obtained from geographic areas was done. Sequence alignment revealed that (i) PvMsp-1 consist of 7 variable blocks interspersed with 8 conserved blocks, (ii) variation is primarily dimorphic, and (iii) potential recombination sites occur throughout the gene. These results suggest that allelic recombination is the major mechanism for generating the diversity in PvMsp-1.

本文研究了地理流行区疟原虫表面抗原的遗传多样性。通过PCR和DNA测序分析约500个分离物，发现如下.恶性疟原虫裂殖子表面抗原基因（PfMsp-1）的多态性：泰国、越南和巴西疟原虫PfMsp-1 5 '区（2-6区）和3'区（17区）多态性位点之间的连锁不平衡这种连锁不平衡的强度与疟疾传播的强度相关。这表明选择和遗传漂变都参与了这种连锁不平衡。PfMsp-1在瓦努阿图的多样性非常有限，5 '-和3' -多态性位点之间存在非常强的连锁不平衡。瓦努阿图的混合克隆感染率极低，表明PfMsp-1的重组率不仅取决于传播强度，还取决于混合感染的频率和流行区存在的等位基因数量。间日疟原虫裂殖子表面抗原基因（PvMsp-1）的多态性：为了深入研究PvMsp-1的结构组织，对从地理区域获得的40个分离株的基因进行了完整的核苷酸测序。序列比对显示，（i）PvMsp-1由7个可变区块和8个保守区块组成，（ii）变异主要是二态性的，（iii）潜在的重组位点出现在整个基因中。这些结果表明等位基因重组是产生PvMsp-1多样性的主要机制。