Kaushal D C, Carter R, Miller L H, Krishna G
Nature. 1980 Jul 31;286(5772):490-2. doi: 10.1038/286490a0.
Asexual proliferation of malaria parasites proceeds by multiplication of the parasites within red cells. Following rupture of the host cells the released merozoites re-invade other red cells. On re-invasion, a proportion of merozoites become, not asexual parasites but gametocytes, the sexual stages infective to the mosquito vectors. Conversion of asexual parasites to gametocytes occurs not only during natural infections but also in continuous in vitro culture as reported first by Trager and Jensen and by others. We showed previously that the proportion of early intra-erythrocytic stages (ring stages) of Plasmodium falciparum which developed into gametocytes in culture was influenced by culture conditions. Gametocyte formation was rare in conditions supporting rapid proliferation but frequent when parasite densisites were static. We now show that nearly 100% of ring stages develop into gametocytes in response to 1mM cyclic AMP in static cultures whereas in rapidly growing cultures few rings become gametocytes in response to cyclic AMP.
疟原虫的无性增殖通过寄生虫在红细胞内的繁殖进行。宿主细胞破裂后，释放出的裂殖子重新侵入其他红细胞。再次侵入时，一部分裂殖子不是变成无性寄生虫，而是变成配子体，即对蚊媒具有感染性的有性阶段。无性寄生虫向配子体的转化不仅发生在自然感染期间，也发生在体外连续培养中，这最早是由特拉格和詹森等人报道的。我们之前表明，恶性疟原虫早期红细胞内阶段（环状体阶段）在培养中发育成配子体的比例受培养条件影响。在支持快速增殖的条件下，配子体形成很少见，但当寄生虫密度稳定时则很常见。我们现在表明，在静态培养中，近100%的环状体阶段在1mM环磷酸腺苷的作用下发育成配子体，而在快速生长的培养物中，很少有环状体在环磷酸腺苷的作用下变成配子体。
