柔嫩艾美耳球虫野外抗药性虫株的RAPD分析

用RAPD方法对柔嫩艾美耳球虫（Eimeria tenella）的8个分别来源于黑龙江、北京、四川、甘肃和广东的中山、新会、东莞以及广州近郊的江村镇的野外分离虫株和2个药物敏感性虫株进行了遗传多态性分析。同时用9种抗球虫药物即马杜霉素（5mg/kg）、盐霉素（60mg/kg）、莫能霉素（120mg/kg）、拉沙菌素（90mg/kg）、克球多（150mg/kg）、常山酮（3mg/kg）、氯氢苯乙氰（1mg/kg）、尼卡巴嗪（125mg/kg）和球痢灵（125mg/kg）分别对8个野不进行抗药性试验，8个虫株对上述药物均有不同程度的抗药性。RAPD分析表明：10个样品都有相似而清晰的主带，每个泳道有5－13条带不等，大小为0.18-2.10kb。它们之间的相似率（SI）大于40.58%，最大的为90.72%，这种相似率属种内变异水平。根据SI值可把10个样品划分为3个类群：广东虫株类群，群内比较，平均SI值为76.60%；广东省外虫株类群，群内比较的平均SI值72.14%；敏感株类群，其间的SI值为89.27%。在另一方面，广东株与广东省外株、敏感株之间比较，其SI的平均值分别仅为63.03%和47.25%，说明柔嫩艾美耳球虫抗药性虫株之间有遗传差异法。

RAPD Analyses of the Drug-resistance Strains of Eimeria Tenella Isolated From Fields

The genetic relatedness of 8 field isolates derived from Heilongjiang,Beijing,Sichuan,Gansu province and Zhongshan,Xinhui,Dongguan,Jiangchun(Guangzhou suburb)of Guangdong province,and 2 drug sensitive strains of Eimeria tenella was assayed by means of random amplified polymorphic DNA(RAPD).The 8 field isolates were determined to be resistant with different extent to 9 anticoccials:maduramacin(5 mg/kg),salinomycin(60 mg/kg),monencin (120 mg/kg),lasanosidum(90 mg/kg),clopidol(150 mg/kg),halofugenone(3mg/kg),diclazuril(1 mg/kg),nicarbazin(125 mg/kg)and zoalene(125 mg/kg).5 different olignucleotides were used to generate similarity coefficients for the drug resistant and sensitive strains of E.tenella. 5 13 DNA segments,depending on the strain primer combination,were amplified with the various primers.Amplification products ranged in size from 0 18 2 10 kb.Band match analyses were used to calculate similarity coefficient(SI).A similarity analysis of E.tenella different strains yielded similarity coefficient of 40 58% 90 72%,belonging to infra species level.SI was very high between 2 drug sensitive strains(89 2%),and among strains(76 6%)derived from Guangdong province,as well as isolates(72 14%)derived from Heilongjiang,Beijing,Sichuan, Gansu province.On the other hand,SI was 63 03% between groups of Guangdong isolates and strains outside Guangdong;47 25% between drug resistant strain(field isolates)and sensitive strains,indicating that genetic difference existed among strains of E.tenella with various drugsensitivity.