Kwa M S, Kooyman F N, Boersema J H, Roos M H
Department of Parasitology and Tropical Veterinary Medicine, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.
Biochem Biophys Res Commun. 1993 Mar 15;191(2):413-9. doi: 10.1006/bbrc.1993.1233.
In vitro selection for benzimidazole (BZ) resistance in the nematode Haemonchus contortus, a parasite of sheep, suggested the involvement of beta-tubilin genes. Two distinct beta-tubulin isotype classes were analyzed. Selection with stepwise increased concentrations of BZ showed for the first time that the increasing degrees of resistance correlate to a dual phase adaptation mechanism. At lower degrees of developing resistance, selection for a single beta-tubulin isotype 1 variant takes place. Subsequently, at higher degrees of drug resistance, an abrupt elimination of individuals carrying beta-tubulin isotype 2 genes in their genome is seen. To evaluate the in vitro experiments we carried out a survey of resistant field populations and found that in the most resistant population (RNO) apparently the same mechanism had happened.
绵羊寄生虫捻转血矛线虫对苯并咪唑（BZ）抗性的体外选择表明β-微管蛋白基因参与其中。分析了两种不同的β-微管蛋白同型类别。用逐步增加浓度的BZ进行选择首次表明，抗性增加程度与双相适应机制相关。在抗性发展程度较低时，会选择单一的β-微管蛋白同型1变体。随后，在耐药性较高时，会发现基因组中携带β-微管蛋白同型2基因的个体被突然淘汰。为了评估体外实验，我们对耐药田间种群进行了调查，发现抗性最强的种群（RNO）显然也发生了同样的机制。
