Niederwieser I, Felger I, Beck H P
Swiss Tropical Institute, Basel, Switzerland.
Exp Parasitol. 2000 Jul;95(3):163-9. doi: 10.1006/expr.2000.4536.
In order to facilitate molecular epidemiological studies on the transmission of the malaria parasite Plasmodium falciparum a sensitive assay for gametocyte detection based on RT-PCR was developed. The transcription of the sexual stage-specific genes Pfs16, Pfs48/45, Pfs230, and Pfs25, as well as the sexual stage- and sporozoite-specific S 18S rRNA, was detected by RT-PCR. S 18S rRNA was present in seven of nine P. falciparum-positive blood samples, despite the lack of microscopic detection of gametocytes and a parasitemia below 0.1%. Expression of the other four gametocyte-specific genes was detected less frequently in malaria-positive blood samples. These findings indicate that RT-PCR of S 18S rRNA is a highly sensitive method for gametocyte detection and, furthermore, that gametocytes are present in the peripheral blood of most malaria carriers, even if the parasitemia is below 0.1%. To determinate the expression pattern of sexual stage-specific genes in more detail, RT-PCR was performed at consecutive time points of highly synchronized monolayer cell cultures. Transcripts of all examined genes except Pfs25 were detected directly after invasion of merozoites of the strain NF54 in red blood cells.
为了促进对恶性疟原虫传播的分子流行病学研究，开发了一种基于逆转录聚合酶链反应（RT-PCR）的配子体检测灵敏测定法。通过RT-PCR检测性阶段特异性基因Pfs16、Pfs48/45、Pfs230和Pfs25以及性阶段和子孢子特异性的S 18S rRNA的转录。尽管在显微镜下未检测到配子体且寄生虫血症低于0.1%，但在9份恶性疟原虫阳性血样中的7份中检测到了S 18S rRNA。在疟疾阳性血样中，其他四个配子体特异性基因的表达检测频率较低。这些发现表明，S 18S rRNA的RT-PCR是一种用于配子体检测的高度灵敏方法，此外，即使寄生虫血症低于0.1%，大多数疟疾携带者的外周血中也存在配子体。为了更详细地确定性阶段特异性基因的表达模式，在高度同步化的单层细胞培养的连续时间点进行了RT-PCR。除Pfs25外，所有检测基因的转录本在NF54株裂殖子侵入红细胞后立即被检测到。
