DETECTION OF RESISTANCE TO IVERMECTIN IN HAEMONCHUS-CONTORTUS
DETECTION OF RESISTANCE TO IVERMECTIN IN HAEMONCHUS-CONTORTUS
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DOI：
10.1016/0020-7519(91)90144-v
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发表时间：
1991-11-01
影响因子：
4
通讯作者：
LACEY, E
中科院分区：
文献类型：
--
作者：
GILL, JH;REDWIN, JM;LACEY, E
感染性的，第三阶段（L3）幼虫的捻转血矛线虫分离株伊维菌素（IVM）的体外IVM诱导的麻痹的敏感性降低。IVM对幼虫运动性的抑制作用可通过在黑暗中在含有IVM的琼脂基质上孵育的L3幼虫中检测到，当暴露于光刺激时，受影响的幼虫无法移动。最佳情况下，阿维菌素（AVM）效价在三个循环后定量，每个循环包括在黑暗中储存24小时，然后短暂暴露于光下。对于IVM敏感分离株，IVM浓度在0.30至0.49 μ m之间时，可实现50%的运动抑制（LP 50），而IVM耐药分离株的LP 50值范围为0.8至2.6 μ m，具体取决于分离株的体内耐药状态。AVM类内结构-活性关系的有限研究表明，L3运动的体外抑制与各类似物的已知体内疗效一致。IVM耐药分离株的耐药因子依赖于AVM结构，极性更强的AVM B2类似物是IVM耐药状态的特别敏感的探针。
Infective, third-stage (L3) larvae of Haemonchus contortus isolates resistant to ivermectin (IVM) show a decreased sensitivity to IVM-induced paralysis in vitro. The inhibition of larval motility by IVM can be detected in L3 larvae incubated in the dark on an agar matrix containing IVM, by the failure of affected larvae to move when stimulated by exposure to light. Optimally, avermectin (AVM) potency is quantified after three cycles, each involving storage in the dark for 24 h followed by a brief exposure to light. For IVM-susceptible isolates, a 50% inhibition of motility (LP50) was achieved with IVM concentrations between 0.30 and 0.49-mu-m, while LP50 values in IVM-resistant isolates ranged from 0.8 to 2.6-mu-m depending on the in vivo resistance status of the isolate. A limited study of structure-activity relationships within the AVM class indicated that in vitro inhibition of L3 motility was consistent with the known in vivo efficacy of each analogue. Resistance factors for IVM-resistant isolates were dependent on AVM structure with the more polar AVM B2 analogue being a particularly sensitive probe of IVM-resistance status.