β-Tubulin genotypes in six species of cyathostomins from anthelmintic-naive Przewalski and benzimidazole-resistant brood horses in Ukraine
β-Tubulin genotypes in six species of cyathostomins from anthelmintic-naive Przewalski and benzimidazole-resistant brood horses in Ukraine
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DOI：
10.1007/s00436-011-2426-0
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发表时间：
2011-10-01
影响因子：
2
通讯作者：
von Samson-Himmelstjerna, Georg
中科院分区：
文献类型：
--
作者：
Blackhall, William J.;Kuzmina, Tetyana;von Samson-Himmelstjerna, Georg
家畜胃肠道线虫对苯并咪唑类（BZ）的耐药性特征在于β-微管蛋白同种型1蛋白（微管的一种组分）中存在特异性多态性。在感染牛、绵羊和山羊的线虫中，与抗性相关的最普遍的多态性发现于密码子200处，在密码子167和198处也有少量多态性。然而，在感染马的cathostomins中，密码子167的多态性似乎比密码子200的多态性更常见。在本研究中，聚合酶链反应扩增的β-微管蛋白片段纳入上述3个多态性位点的同种型1和2基因的6种cathostomins，Cylicocyclus nassatus，Cylicocyclus ashglii，Cyathostomum catinatum，Cylicostephanus goldi，Cylicostephanus longibursatus，Coronocyclus coronatus，进行了集中分析。从两个不同的马种群中采集蠕虫，即从Askania-Nova生物圈保护区的普氏野马（从未接受过任何驱虫剂治疗）和Dubrovsky农场的育马（已建立苯并咪唑耐药性）中采集。从每个种和种群的三个蠕虫以及50个雄性C. nassatus和C.从两个种群中分离出来。与密码子200相比，绝大多数与puerectin BZ抗性相关的TAC等位基因位于密码子167。前等位基因发生在同种型1中的所有6个物种的假定苯并咪唑耐药cathostomins Dubrovsky马。没有发现与抗性相关的多态性，在相应的同型2密码子，也不是在密码子198中的任何6种cathostomins（既不是单一的，也不是合并蠕虫DNA）从两个人口。这些发现进一步支持β-微管蛋白同种型1和其中的密码子167与cathostomins中的BZ抗性的主要关联。
Resistance to benzimidazoles (BZ) in the gastrointestinal nematodes of livestock is characterised by the presence of specific polymorphisms in the beta-tubulin isotype 1 protein, a component of microtubules. The most prevalent polymorphism associated with resistance in nematodes infecting cattle, sheep, and goats is found at codon 200, with minor occurrences of polymorphisms at codons 167 and 198. In the cyathostomins that infect horses, however, a polymorphism at codon 167 appears to be more common than the codon 200 polymorphism. In the present study, a focussed analysis of PCR-amplified beta-tubulin fragments incorporating the above-mentioned three polymorphic sites in isotype 1 and 2 genes in worms of six species of cyathostomins, Cylicocyclus nassatus, Cylicocyclus ashworthi, Cyathostomum catinatum, Cylicostephanus goldi, Cylicostephanus longibursatus, and Coronocyclus coronatus, was performed. Worms were collected from two distinct horse populations, i.e. they were collected from Przewalski horses of the Askania-Nova Biosphere Reserve that had never received any anthelmintic treatment and from brood horses of the Dubrovsky farm where benzimidazole resistance had become established. DNA was extracted and sequenced from three worms of each species and population as well as from pools of 50 male C. nassatus and C. catinatum from both populations. The vast majority of putatively BZ resistance-associated TAC alleles were found at codon 167, compared to codon 200. The former allele occurred in isotype 1 in all six species of the supposedly benzimidazole-resistant cyathostomins from Dubrovsky horses. None of the polymorphisms associated with resistance was found in the corresponding isotype 2 codons nor at codon 198 in any of the six species of cyathostomins (neither single nor pooled worm DNA) from either of the two populations. These findings further support the predominant association of beta-tubulin isotype 1 and therein codon 167 with BZ resistance in cyathostomins.