Kreutzer R D, Yemma J J, Grogl M, Tesh R B, Martin T I
Department of Biology, Youngstown State University, Ohio.
Am J Trop Med Hyg. 1994 Sep;51(3):301-7. doi: 10.4269/ajtmh.1994.51.301.
Parasitic protozoa of the genus Leishmania (Kinetoplastida: Trypanosomatidae) are generally thought to multiply by binary fission; however, data from quantitative microspectrophotometry indicate that nuclear fusion or sexual reproduction takes place in the intracellular amastigote form. Among several different Leishmania species, the mean +/- SD nuclear DNA content of all promastigotes (extracellular form) and of some amastigotes (intracellular form) in macrophages was 0.098 +/- 0.032 relative units; in contrast, other amastigotes within the same macrophage had a mean +/- SD nuclear DNA content of 0.219 +/- 0.050. The latter population of amastigotes are apparently produced when the nuclei of a pair of 0.098 amastigotes fuse. These 0.219 amastigotes later go through what is probably the typical meiotic cycle to reform the 0.098 condition we observed among promastigotes. The demonstration of sexual reproduction in Leishmania has important implications for the future direction of research on this medically important parasite.
利什曼原虫属（动基体目：锥虫科）的寄生原生动物通常被认为通过二分裂进行繁殖；然而，定量显微分光光度法的数据表明，细胞核融合或有性生殖发生在细胞内无鞭毛体形式中。在几种不同的利什曼原虫物种中，巨噬细胞内所有前鞭毛体（细胞外形式）和一些无鞭毛体（细胞内形式）的平均±标准差核DNA含量为0.098±0.032相对单位；相比之下，同一巨噬细胞内的其他无鞭毛体的平均±标准差核DNA含量为0.219±0.050。后一群无鞭毛体显然是由一对核DNA含量为0.098的无鞭毛体的细胞核融合产生的。这些核DNA含量为0.219的无鞭毛体随后经历了可能是典型的减数分裂周期，以恢复我们在前鞭毛体中观察到的0.098的状态。利什曼原虫有性生殖的证明对这种具有重要医学意义的寄生虫的未来研究方向具有重要意义。
