Stevens J R, Mathieu-Daudé F, McNamara J J, Mizen V H, Nzila A
UMR CNRS/ORSTOM 9926: Génétique Moléculaire des Parasites et des Insectes Vecteurs, Montpellier, France.
Trop Med Parasitol. 1994 Dec;45(4):313-8.
In many previous characterization studies of Trypanozoon, isolates have been subpassaged numerous times in laboratory rodents until a quantity of trypanosomes sufficient for analysis has been obtained. In addition to the numerous biochemical effects of such a process on the parasite, it appears probable that adaptation to an unnatural host may also serve to filter out less virulent populations from mixed infections, leading to an underestimate of the true level of genetic diversity. By the early cloning of trypanosomes from susceptible captive flies infected from the primary isolate--the midgut of a wild tsetse--the present study provides evidence of the range of genetically different Trypanosoma brucei populations which may coexist within the midgut of individual tsetse flies in nature. The three primary isolates from tsetse yielded one, five and nine genetically distinct populations. Cloned populations were confirmed as T. brucei using the polymerase chain reaction, and were characterized by karyotype analysis and multilocus isoenzyme electrophoresis. These data allowed a limited assessment of the level of genetic variability in natural populations of T. brucei.
在许多先前对布氏锥虫属的特征研究中，分离株已在实验室啮齿动物中多次传代，直到获得足以进行分析的大量锥虫。除了这一过程对寄生虫产生的众多生化影响外，适应非天然宿主似乎也可能会从混合感染中筛选出毒性较弱的群体，从而导致对真正的遗传多样性水平估计不足。通过从感染了原始分离株（野生采采蝇的中肠）的易感圈养采采蝇中早期克隆锥虫，本研究提供了证据，证明了在自然界中单个采采蝇中肠内可能共存的遗传不同的布氏锥虫群体的范围。从采采蝇中获得的三个原始分离株分别产生了1个、5个和9个遗传上不同的群体。使用聚合酶链反应确认克隆群体为布氏锥虫，并通过核型分析和多位点同工酶电泳对其进行特征分析。这些数据使得能够对布氏锥虫自然群体中的遗传变异性水平进行有限的评估。
