Sutherland Colin J, Alloueche Ali, McRobert Louisa, Ord Rosalynn, Leggat Jamie, Snounou Georges, Pinder Margaret, Targett Geoffrey A T
Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom.
Am J Trop Med Hyg. 2002 Jun;66(6):700-5. doi: 10.4269/ajtmh.2002.66.700.
The genetic complexity of Plasmodium falciparum gametocytes isolated from Gambian children participating in a controlled trial of anti-malarial therapy was investigated. RNA and DNA were prepared from gametocyte-positive blood, which was also used in transmission experiments with Anopheles gambiae mosquitoes. Amplification by a reverse transcriptase-polymerase chain reaction (RT-PCR) of transcripts from the genes for the ring-infected erythrocyte surface antigen and the 16-kD antigen, which exhibit asexual and sexual stage-specific expression, was used to identify 30 post-treatment gametocyte isolates in which trophozoites persisted below the threshold of detection by microscopy. These included isolates from children who received sulfadoxine/pyrimethamine plus artesunate. Twenty-nine gametocyte-positive isolates that were free of subpatent trophozoites were examined further by PCR amplification of polymorphic genomic loci. We estimate that an average minimum of 2.3 genotypes occurred in these gametocyte-only isolates, and many of these were shown to be infective to mosquitoes. Thus, meiotic recombination between different genotypes is predicted to be a common event in this study area.
对从参与抗疟治疗对照试验的冈比亚儿童中分离出的恶性疟原虫配子体的遗传复杂性进行了研究。从配子体阳性血液中提取RNA和DNA，这些血液也用于冈比亚按蚊的传播实验。通过逆转录聚合酶链反应（RT-PCR）扩增环状感染红细胞表面抗原和16-kD抗原基因的转录本，这些抗原表现出无性和有性阶段特异性表达，用于鉴定30个治疗后配子体分离株，其中滋养体持续低于显微镜检测阈值。这些包括来自接受磺胺多辛/乙胺嘧啶加青蒿琥酯治疗儿童的分离株。通过对多态性基因组位点进行PCR扩增，进一步检查了29个无亚临床滋养体的配子体阳性分离株。我们估计，这些仅含配子体的分离株平均至少出现2.3种基因型，其中许多被证明对蚊子具有感染性。因此，预计不同基因型之间的减数分裂重组在该研究区域是一个常见事件。
