Dougherty C T, Knapp F W, Bush L P, Maul J E, Van Willigen J
Department of Agronomy, University of Kentucky, Lexington 40546-0091, USA.
J Med Entomol. 1998 Sep;35(5):798-803. doi: 10.1093/jmedent/35.5.798.
Larvae of arthropod ectoparasites of livestock, such as the horn fly, Haematobia irritans (L.), may be exposed to acyl-loline alkaloids in dung of ruminant livestock ingesting herbage of the tall fescue (Festuca arundinacea Schreb.)-endophyte association [Neotyphodium coenophialum (Morgan-Jones & W. Gams) Glenn, Bacon & Hanlin comb. nov.]. Biological activity of alkaloid-supplemented bovine dung was assayed by growth, development, and survival of 1st instars of horn fly. An extract from tall fescue seed, containing N-formyl loline (NFL), N-acetyl loline (NAL), and loline (59:21:20 by mass, respectively) caused 100% mortality of horn fly larvae when dung was supplemented at > or = 100 micrograms/g. Probit analysis of data corrected for natural mortality indicated a LD50 of 30 micrograms/g (95% fidicial limits: 20-49 micrograms/g). When horn fly larvae were introduced to dung supplemented with up to 50 microM of acyl-loline derivatives, mortality of larvae varied significantly between alkaloids (P < 0.0001). Probit analysis indicated that NFL [LD50: 34 microM (95% fidicial limits: 3-53 microM)] was more toxic than NAL [LD50: 46 microM (0-83 microM)], and that loline hydrochloride was not toxic.
家畜的节肢动物外寄生虫幼虫，如角蝇（Haematobia irritans (L.)），可能会接触到反刍家畜粪便中的酰基麦角碱生物碱，这些家畜食用了高羊茅（Festuca arundinacea Schreb.）-内生真菌共生体（Neotyphodium coenophialum (Morgan-Jones & W. Gams) Glenn, Bacon & Hanlin comb. nov.）的牧草。通过角蝇一龄幼虫的生长、发育和存活情况来测定添加生物碱的牛粪的生物活性。高羊茅种子提取物含有N-甲酰基麦角碱（NFL）、N-乙酰基麦角碱（NAL）和麦角碱（质量比分别为59:21:20），当牛粪中添加量≥100微克/克时，可导致角蝇幼虫100%死亡。对校正了自然死亡率的数据进行概率分析表明，半数致死剂量（LD50）为30微克/克（95%置信限：20 - 49微克/克）。当将角蝇幼虫引入添加了高达50微摩尔酰基麦角碱衍生物的牛粪中时，不同生物碱处理下幼虫的死亡率差异显著（P < 0.0001）。概率分析表明，NFL [LD50: 34微摩尔（95%置信限：3 - 53微摩尔）]比NAL [LD50: 46微摩尔（0 - 83微摩尔）]毒性更强，而盐酸麦角碱无毒。
