Nature Research Centre, Akademijos 2, Vilnius, LT-08412, Lithuania,
Parasitol Res. 2014 Apr;113(4):1417-23. doi: 10.1007/s00436-014-3782-3. Epub 2014 Jan 31.
Recent in vitro experimental studies reported the complex patterns of haemosporidian (Haemosporida) between-lineage interactions, which prevent mixing of lineages during simultaneous sexual process. Numerous anomalous ookinetes have been observed; these are not involved in sporogony. Massive development of such ookinetes might influence parasite transmission but is insufficiently investigated. The simultaneous sexual process of several lineages is a common phenomenon in vectors due to high prevalence of haemosporidian co-infections in wildlife. It remains unclear if the number of anomalous ookinetes changes during dual-infection sporogony in comparison with the single-infection process. We calculated proportions of the anomalous and normal ookinetes, which developed during single-infection (control) and dual-infection experiments in vitro conditions. Three mitochondrial cytochrome b lineages belonging to three Haemoproteus spp. (Haemosporida, Haemoproteidae) were isolated from naturally infected passerine birds. Sexual process and ookinete development were initiated in vitro by mixing blood containing mature gametocytes of two different parasites; the following experiments were performed: (1) Haemoproteus tartakovskyi (lineage hSISKIN1) × Haemoproteus lanii (lineage hRBS4) and (2) Haemoproteus belopolskyi (hHIICT3) × H. lanii (hRBS4). Genetic difference between lineages was 5.0-5.9%. Normal and anomalous ookinetes developed in all control and dual-infection experiments. The number of anomalous ookinetes markedly decreased, and normal ookinetes increased in all dual-infection experiments in comparison with those in controls, except for H. belopolskyi, in which proportion of the anomalous and normal ookinetes did not change. This study shows that simultaneous sexual process of two genetically distant lineages of haemosporidian parasites might increase the efficiency of reproductive cells, resulting in the development of a greater number of normal ookinetes. The marked increase of the number of normal ookinetes, which is involved in sporogony, indicates the success of sporogony in dual infections. Some haemosporidian lineages might benefit from simultaneous sporogony. Widespread avian Haemoproteus spp. are convenient and laboratory-friendly organisms for in vitro experimental research addressing between-lineage interaction in parasites during the sexual process.
最近的体外实验研究报告了血孢子虫（Haemosporida）种系间相互作用的复杂模式，这些模式阻止了在同时的有性过程中种系的混合。已经观察到许多异常的合子；这些合子不参与孢子发生。大量发育的异常合子可能会影响寄生虫的传播，但研究还不够充分。由于野生动物中血孢子虫的共同感染率很高，几种种系的同时有性过程在载体中是很常见的现象。目前尚不清楚在双重感染孢子发生过程中，异常合子的数量与单一感染过程相比是否发生变化。我们计算了在体外条件下，单一感染（对照）和双重感染实验中发育的异常和正常合子的比例。从自然感染的雀形目鸟类中分离出属于三种疟原虫（Haemosporida，Haemoproteidae）的三种线粒体细胞色素 b 种系。通过混合含有两种不同寄生虫成熟配子体的血液在体外启动有性过程和合子发育；进行了以下实验：（1）Haemoproteus tartakovskyi（hSISKIN1 种系）× Haemoproteus lanii（hRBS4 种系）和（2）Haemoproteus belopolskyi（hHIICT3 种系）× H. lanii（hRBS4 种系）。种系间的遗传差异为 5.0-5.9%。在所有对照和双重感染实验中，正常和异常合子都有发育。除了 H. belopolskyi 之外，在所有双重感染实验中，异常合子的数量明显减少，而正常合子的数量增加，与对照相比，在 H. belopolskyi 中，异常和正常合子的比例没有变化。这项研究表明，两种遗传上遥远的血孢子虫寄生虫同时发生有性过程可能会提高生殖细胞的效率，从而导致更多正常合子的发育。参与孢子发生的正常合子数量的显著增加表明双重感染中的孢子发生成功。一些血孢子虫种系可能会从同时的孢子发生中受益。广泛存在的鸟类疟原虫是方便和实验室友好的生物体，可用于体外实验研究，以解决寄生虫在有性过程中的种系间相互作用。
