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目的 研究云南省现场恶性疟原虫 3个与抗疟药抗性有关的dhfr、pfmdr1和pfcrt的点突变特征 ,为抗药性恶性疟原虫的分子生物学研究提供背景资料。 方法 应用特异性套式多聚酶链反应 (PCR)和限制性酶切片段长度分析 (RFLP)方法 ,检测恶性疟现症病人干滤纸血样的恶性疟原虫 3个抗药性基因点突变情况。 结果 恶性疟原虫dhfr基因内 16,5 1,10 8和 164位氨基酸有不同程度的突变 ,突变型比例高 ,以Asn -10 8和Ⅰle -5 1为甚 ,频度分别为94 3 %和 81 3 %。野生型 ( 3D7型 )Ser -10 8出现较低频率 8 6% ,而AIa -16出现频率较高 68 6% ;pfcrt基因的 76位点由K突变为T ,突变型 (含混合 )占 96 7% ;野生型仅占 3 4% ;pfmdr1基因 86位点由Asn突变为Tyr ,突变型占 3 4 % ;野生型点 48 7% ;混合型占 16 7%。未发现 12 46位点突变的存在。 结论 云南现场恶性疟原虫与抗疟药抗性有关的3个pfdhfr、pfmdr1和pfcrt基因有较广泛的点突变特征。
Objective To study the point mutation characteristics of dhfr, pfmdr1 and pfcrt in Plasmodium falciparum related to antimalarial resistance in Yunnan Province, and to provide background information for the molecular biology of Plasmodium falciparum. Methods The specific resistance of Plasmodium falciparum to dry spot filter paper in patients with falciparum malaria was detected by specific nested polymerase chain reaction (PCR) and restriction fragment length analysis (RFLP). As a result, 16,5 1,108 and 164 amino acids in the dhfr gene of P. falciparum were mutated to different extents, and the percentage of mutant type was high. The frequencies of Asn -10 8 and Ile -5 1 were 94 3% 81 3%. In the wild type (3D7 type) Ser -10 8 appeared lower frequency of 8.6%, while AIa -16 appeared higher frequency of 68.6%; 76 points of pfcrt gene changed from K to T, and mutant type 7%; wild type only accounted for 34%; pfmdr1 gene 86 mutation from Asn to Tyr, mutation accounted for 34%; wild-type point 48 7%; mixed accounted for 16 7%. No mutation at 1246 locus was found. Conclusion The three pfdhfr, pfmdr1 and pfcrt genes related to the resistance of Plasmodium falciparum to antimalarial drugs in Yunnan Province are characterized by a wide range of point mutations.