氟虫腈和阿维菌素对小菜蛾及其寄生蜂半闭弯尾姬蜂的毒力研究

通过药膜法和喷雾法分别测定了氟虫腈和阿维菌素对小菜蛾及其天敌半闭弯尾姬蜂的室内毒力和田间药效。结果表明,氟虫腈和阿维菌素对小菜蛾幼虫具有很高的毒力和良好的田间防治效果,致死中浓度LC50分别为1.105 mg/L和1.602 mg/L,田间防效分别为90.91%和82.02%;氟虫腈和阿维菌素对半闭弯尾姬蜂的LC50分别为2.281 mg/L和6.036 mg/L,选择指数分别为2.064和3.768,对此天敌较为安全;但是田间药效试验却表明氟虫腈和阿维菌素对半闭弯尾姬蜂具有相当的负面影响。     

Comparison of the persistent activity of ivermectin, abamectin, doramectin and moxidectin in cattle in Zambia

The persistent efficacy of four commercially available macrocyclic lactones (ML) in maintaining reduced faecal egg counts in cattle grazing naturally infested pastures was evaluated in 44 zebu animals aged 1–2 years in Zambia. The study started in February (rainy season) when the strongyle egg output was increasing. Four days before the start of the trial, all animals were treated with a double dose of oxfendazole. They were then divided into five groups which were again treated on day 0. Groups A, D, I and M received 0.2 mg kg⁻¹ of abamectin, doramectin, ivermectin and moxidectin, respectively. Animals of group C received albendazole (7.5 mg kg⁻¹). Faecal samples were collected twice a week for egg counts and larval differentiation. Faecal egg counts in the C group increased from day 21 onwards and plateaued from day 42 between 180 and 380 eggs per gram. The main genera found in cultures were Cooperia (90%) and Haemonchus (7%). Faecal egg excretion in groups M, A, D and I started on day 35, 42, 42 and 45, respectively. subsequently and until day 84, average counts in these four groups were always significantly lower than in group C. Compared with albendazole, all four ML gave over 95% reduction in cumulative faecal egg counts for 42 days after treatment. The percentage efficacy was still over 84% by day 84 when an average cumulative egg count of 11 320 eggs per gram faeces was calculated in group C. In addition, there was no significant difference in efficacy between the four ML groups at any of the sampling dates. During the trial no significant difference in weight gain between any of the groups was observed.     

Susceptibility of Rhipicephalus (Boophilus) microplus to ivermectin (200, 500 and 630 μg/kg) in field studies in Brazil

The present study aimed to determine the susceptibility of 17 Rhipicephalus (Boophilus) microplus populations, originating in the Southeast and Southern regions of Brazil, to different ivermectin concentrations (200, 500 and 630 μg/kg), administered through subcutaneous or topical (pour-on) routes. R. (B.) microplus populations from the states of Minas Gerais (seven populations), São Paulo (seven populations) and Paraná (three populations) were chosen for the tests. The selected cattle were allocated to treatment groups on day 0, and block formation was based on the arithmetic mean of female ticks (4.5–8.0 mm long) counted on three consecutive days (−3, −2 and −1). To evaluate the therapeutic and residual efficacies of these formulations, tick counts (females ranging from 4.5 to 8.0 mm long) were performed on days 3, 7 and 14 post-treatment, and continued on a weekly basis thereafter until the end of each experiment. The results obtained throughout this study, utilizing field efficacy studies, allowed us to conclude that the resistance of R. (B.) microplus against 200 and 500 μg/kg ivermectin is widely disseminated because all tick populations that had contact with these specific concentrations were diagnosed as resistant. However, it is possible to infer that R. (B.) microplus resistance against 630 μg/kg ivermectin was also widespread, diagnosed at six of ten analyzed properties. Resistance of these ectoparasites to 630 μg/kg ivermectin is most likely emerging in three other populations of R. (B.) microplus. Strategies of resistance management need to be quickly determined to keep the selection pressure at a minimum level in Brazil.     

阿维菌素对小鼠雌性生殖细胞的致突变性研究

阿维菌素是我国生产的一种高效广谱抗寄生虫抗生素，对动物的消化道线虫和外寄生虫有很强的驱杀作用。本文选择了第二次减数分裂中期相（ＭＩＩ）卵母细胞和第一次分裂中期相合子染色体畸变分析方法，研究其对哺乳动物雌性生殖细胞的遗传毒性。１．ＭＩＩ卵母细胞染色体畸变分析：根据阿维菌素的小鼠急性毒性试验结果（小鼠经口ＬＤ５０＝１９．１９ｍｇ／ｋｇ），设以下剂量组：１．９２、３．８４和９．６０ｍｇ／ｋｇ（约相当于１     

30%螺螨磺酯?阿维菌素可分散油悬浮剂的配方及生物活性

测试了不同复配比例的螺螨磺酯、阿维菌素对二斑叶螨的毒力,确定最佳药效的原药比例;通过对乳化剂、增效剂的筛选,获得了30%螺螨磺酯?阿维菌素可分散油悬浮剂(OD)的最优配方;测试了其对苹果二斑叶螨、柑橘红蜘蛛的田间防效。30%螺螨磺酯?阿维菌素OD的配方组成为：螺螨磺酯27%、阿维菌素3%、YUS FS3000 4%、601# 5%、T-20 7%、有机膨润土2%、GY-T0304 0.4%、油酸甲酯补足至100%,其各项性能符合可分散油悬浮剂的要求,田间药效试验表明其对二斑叶螨和柑橘红蜘蛛的防效优于对照药剂30%螺螨酯.阿维菌素OD,并且持效期长,具有良好的开发前景。     

阿维菌素对稻纵卷叶螟的室内毒力测定

通过室内毒力测定表明,阿维菌素对稻纵卷叶螟的LC50为0.27mg/L,室内毒力远低于对照毒死蜱。     

60Co γ射线辐照选育阿维链霉菌及辐射效应研究

[目的]采用60Coγ射线辐照选育阿维链霉菌,筛选B1a产量提高的突变菌株。[方法]用60Coγ射线作为诱变源,在辐照剂量200～1 600 Gy、剂量率10 Gy/min的条件下对一株未经任何诱变的微生物农药阿维菌素菌株Av2进行了诱变改良;对该菌株的致死率、突变率、菌落形态变化与60Coγ射线辐照剂量的关系进行了探讨,其中初筛采用抑菌圈法,复筛采用摇瓶培养发酵,阿维菌素含量测定采用高效液相色谱法。[结果]在800 Gy辐射剂量下得到了Av2-m212、Av2-m245和Av2-m286 3株高效突变菌,其Bla产量分别比原始菌株提高了36%、41%和46%,均属于皱缩型菌株。高于30%的正突变菌均在800 Gy辐射剂量下产生,该剂量点是致死率和正突变率趋于平稳的交叉点。辐照后皱缩型和火山型突变菌有正突变菌,其他形态菌株均为负突变。[结论]60Coγ射线在阿维菌素产生菌的诱变筛选中起到了重要作用,是一种非常有效的微生物诱变育种方法。     

阿维菌素纳米脂质体的制备及品质控制

利用正交试验设计,筛选、优化处方和工艺,制备阿维菌素纳米脂质体,并考察其稳定性。采用改良薄膜分散法制备阿维菌素纳米脂质体(AVMNL),用透射电镜、激光粒度分布仪等对其理化性质进行研究。用紫外可见分光光度法测定AVMNL中AVM(阿维菌素)的质量浓度,并通过热稳定试验和光照试验考察其稳定性。结果显示,制备方法的最佳处方工艺组合为卵磷脂与胆固醇,其质量比为9∶1,AVM与磷脂质量比为1∶10,缓冲液PBS的pH为7.0,超声裂解时间为5min,蒸发温度为40℃,冻融3次。AVMNL是乳白色均一稳定的牛奶状液体,其平均粒径为198.2nm。AVMNL在不同温度下放置0、5、10d后,无分层、沉淀现象发生,色泽均呈乳白色,包封率和药物质量浓度均未发生明显变化。3批AVMNL在光照度为(4 500±500)lx、2.0~5.0℃放置0、5、10d后,其外观未发生明显变化,为乳状均一的液体,无絮凝、药物析出现象,但药物的包封率和质量浓度有所降低。制备的纳米脂质体符合要求,粒径分布范围窄,且比较均匀,对热稳定,对光的稳定性较差,应避光保存。     

阿维菌素类药物在动物性食品中的残留检测研究概况

为了对动物性食品中阿维菌素类残留研究有更深入、全面的了解,并为我国开展阿维菌素类残留检测提供参考,文章综述了阿维菌素类药物(包括阿维菌素、伊维菌素、多拉菌素、依立菌素和莫西菌素)在动物性食品中的单残留和多残留检测方法,包括薄层色谱法、酶联免疫法、高效液相色谱法、液质联用法和液相色谱?质谱?质谱联用法。     

阿维菌素高产菌的诱变育种研究

[目的]选育B1a组分较高的阿维菌素高产菌株。[方法]通过紫外线-氯化锂(LiCl)和紫外线-亚硝基胍(NTG)对阿维链霉菌N-5-6进行了复合诱变处理。[结果]以1.00 mol/L的LiCl和60s的紫外线照射时间以及以45 s的UV照射时间和0.8 mg/ml的NTG浓度分别对出发菌株进行复合诱变处理,通过筛选得到13株总效价比出发菌株提高了20%以上的突变株,经HPLC检测,其中7株B1a组分含量较高,均在45%以上。菌株H02180的B1a含量达到了51.35%,比出发菌株N-5-6的B1a含量提高了65.1%;菌株H02108的B1a含量达到了51.26%,比出发菌株N-5-6的含量提高了64.8%。[结论]采用紫外线和氯化锂、紫外线和亚硝基胍这2种复合诱变方法对于阿维链霉菌的高产菌株的选育是有效的。