Sharma Y D
Department of Biotechnology, All India Institute of Medical Sciences, New Delhi.
Indian J Med Res. 2005 Jan;121(1):13-22.
Plasmodium falciparum shows plasticity in its genome. For its survival it can delete certain genes (or portions) if not needed for its growth and has the capability to regulate its genes under various stages of its life cycle as well as under unfavourable environmental conditions. Parasite shows enormous amount of antigenic variation under immune pressure leading to the emergence of vaccine resistant strains. Similarly, under drug pressure it allows mutations to settle in the target genes. It is becoming more and more clear that with the continuous exposure to a drug, the parasite accumulates more and more number of mutations in these genes. By measuring the number of these point mutations among field isolates one can predict the efficacy of a particular drug. Therefore, these markers are useful tools at epidemiological level. This molecular surveillance can also help in slowing down the drug resistance if supported by a careful drug usage policy. Further studies are required to develop molecular markers for rest of the antimalarial drugs as well as the improvement on the existing molecular tools for accurate and rapid detection of drug resistant malaria.
恶性疟原虫在其基因组方面表现出可塑性。为了生存,它可以删除某些生长不需要的基因(或部分基因),并且有能力在其生命周期的各个阶段以及不利的环境条件下调节其基因。寄生虫在免疫压力下表现出大量的抗原变异,导致出现疫苗抗性菌株。同样,在药物压力下,它允许突变在靶基因中固定下来。越来越清楚的是,随着持续接触一种药物,寄生虫在这些基因中积累越来越多的突变。通过测量野外分离株中的这些点突变数量,可以预测一种特定药物的疗效。因此,这些标记物是流行病学层面的有用工具。如果有谨慎的药物使用政策支持,这种分子监测也有助于减缓耐药性。还需要进一步研究来开发其他抗疟药物的分子标记物,以及改进现有的分子工具,以便准确、快速地检测耐药性疟疾。