The family Trypanosomatidae encompasses parasitic flagellates, some of which cause serious vector-transmitted diseases of humans and domestic animals. However, insect-restricted parasites represent the ancestral and most diverse group within the family. They display a range of unusual features and their study can provide insights into the biology of human pathogens. Here we describe Vickermania, a new genus of fly midgut-dwelling parasites that bear two flagella in contrast to other trypanosomatids, which are unambiguously uniflagellate. Vickermania has an odd cell cycle, in which shortly after the division the uniflagellate cell starts growing a new flagellum attached to the old one and preserves their contact until the late cytokinesis. The flagella connect to each other throughout their whole length and carry a peculiar seizing structure with a paddle-like apex and two lateral extensions at their tip. In contrast to typical trypanosomatids, which attach to the insect host’s intestinal wall, Vickermania is separated from it by a continuous peritrophic membrane and resides freely in the fly midgut lumen. We propose that Vickermania developed a survival strategy that relies on constant movement preventing discharge from the host gut due to intestinal peristalsis. Since these parasites cannot attach to the midgut wall, they were forced to shorten the period of impaired motility when two separate flagella in dividing cells interfere with each other. The connection between the flagella ensures their coordinate movement until the separation of the daughter cells. We propose that Trypanosoma brucei, a severe human pathogen, during its development in the tsetse fly midgut faces the same conditions and follows the same strategy as Vickermania by employing an analogous adaptation, the flagellar connector.

中文翻译：

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Vickermania根。十一月，使用两个联合鞭毛抵抗蝇宿主内中肠蠕动的锥虫

锥虫科（Trypanosomatidae）包括寄生的鞭毛虫，其中一些会引起严重的媒介传播的人类和家畜疾病。但是，昆虫限制的寄生虫代表了这个家庭的祖先和最多样化的群体。它们显示出一系列不同寻常的特征，他们的研究可以提供对人类病原体生物学的深刻见解。在这里，我们描述了维氏蠕虫，一种新的蝇类中肠寄居寄生虫，带有两个鞭毛，而其他锥虫却毫无疑问是单鞭毛。维氏躁狂症具有奇数细胞周期，其中分裂后不久，单鞭毛细胞开始生长附着在旧鞭毛上的新鞭毛，并保持它们的接触直至晚期胞质分裂。鞭毛在它们的整个长度上相互连接，并带有一种特殊的抓住结构，该结构具有桨状的先端和在其顶端的两个侧向延伸部。与附着在昆虫寄主肠壁上的典型锥虫不同，维氏狂热菌通过连续的营养膜将其隔离开，并自由地生活在中肠蝇腔中。我们建议维氏躁狂症开发了一种生存策略，该策略依赖于恒定运动来防止由于肠蠕动而从宿主肠道排出。由于这些寄生虫无法附着在中肠壁上，因此当分裂细胞中的两个分离鞭毛相互干扰时，它们被迫缩短了运动能力受损的时间。鞭毛之间的连接确保它们的坐标运动，直到子细胞分离。