红蓼提取物对13种农业害虫触杀活性的研究

关于红蓼提取物对农业害虫的触杀活性,国内外研究甚少。研究红蓼提取物对害虫的触杀活性,可为利用该植物研制新型植物源杀虫剂提供理论依据。本研究采用浸渍法测定了红蓼提取物对害虫的触杀活性,结果表明,红蓼种子乙酸乙酯萃取物对粘虫、菜粉蝶、棉铃虫、甘蓝夜蛾、甜菜夜蛾和小地老虎4~5龄幼虫具有很强的触杀活性,在16.80 g/L浓度下的校正死亡率在87.50%~100%;对小菜蛾3龄幼虫也具有很强的触杀活性,在21.00 g/L浓度下的校正死亡率为92.85%;秋季茎秆乙酸乙酯萃取物对菜粉蝶4龄幼虫和粘虫5龄幼虫具有很强和较强的触杀活性,在33.60 g/L浓度下的校正死亡率分别为100%和59.20%。盛花期茎秆石油醚粗提物对棉蚜具有较强的触杀活性,在0.27 g/L浓度下的校正死亡率为51.65%。盛花期花石油醚和甲醇粗提物对朱砂叶螨具有很强的触杀活性,在0.13和1.15 g/L浓度下的校正死亡率均高达100%。     

唐古特莨菪中生物碱的分离、鉴定与生物活性研究

研究唐古特莨菪中生物碱对农业害虫(螨)的生物活性,可为利用该植物研制新型植物源杀虫(螨)剂提供理论依据。本文采用柱色谱分离法从唐古特莨菪地上部分分离得到2个生物碱类化合物,通过MS、NMR确定了其化学结构,分别为莨菪碱、东莨菪碱。采用微量点滴法和玻片浸渍法测定了莨菪碱、东莨菪碱对甘蓝蚜、桃蚜等9种蚜虫和朱砂叶螨、二斑叶螨等4种叶螨的触杀活性。结果表明,莨菪碱对禾谷缢管蚜、桃粉蚜、豆蚜和绣线菊蚜具有较强的触杀作用,LC₅₀值分别为257.863,275.459,344.645和344.717 mg/L。东莨菪碱对豆蚜和禾谷缢管蚜具有较强的触杀作用,LC₅₀值分别为311.585和392.309 mg/L。对照药剂鱼藤酮对甘蓝蚜和棉蚜具有较强的触杀作用,LC₅₀值分别为399.542和436.124 mg/L。对甘蓝蚜等9种蚜虫的触杀作用,莨菪碱强于或与东莨菪碱相当;对豆蚜、禾谷缢管蚜的触杀作用,莨菪碱和东莨菪碱均强于鱼藤酮;对甘蓝蚜、桃蚜和棉蚜的触杀作用,莨菪碱和东莨菪碱均弱于鱼藤酮。莨菪碱和东莨菪碱对截形叶螨、山楂叶螨、二斑叶螨和朱砂叶螨具有较强的触杀作用。2种生物碱对4种叶螨的毒力相当,对二斑叶螨和朱砂叶螨的毒力(201.027~224.172 mg/L)均高于截形叶螨和山楂叶螨(257.014~332.698 mg/L)。对照药剂鱼藤酮对截形叶螨、山楂叶螨的LC₅₀值分别为196.847和224.592 mg/L,其毒力高于莨菪碱和东莨菪碱。     

红蓼提取物杀虫活性及其对粘虫的作用方式

采用虫体浸渍法和夹毒叶碟法等方法研究红蓼(Polygonum orientale L.)提取物杀虫活性及其对粘虫的作用方式,为利用该植物研制新型植物源杀虫剂提供理论依据。结果表明,红蓼的最高杀虫活性部位是种子和秋季茎秆,甲醇提取物稀释5倍液对粘虫(Mythi mnaseparate Walker)5龄幼虫的触杀死亡率分别为21.18%和20.29%。种子不同极性溶剂提取物的触杀作用以乙醇最强,校正死亡率可达41.97%;秋季茎秆则以甲醇最强,校正死亡率为20.29%。种子和秋季茎秆乙酸乙酯萃取物的触杀死亡率分别为88.89%和59.20%,二者的LC50值分别为8.6466 g(浸膏)/L和29.0484 g(浸膏)/L。种子和秋季茎秆乙酸乙酯萃取物稀释10倍液对菜粉蝶(Pieris rapae L.)4龄幼虫的触杀死亡率均达100%,种子乙酸乙酯萃取物稀释5倍液对小菜蛾(Plutella xylostella L.)3龄幼虫、棉铃虫(Helicoverpa armigera Hbner)和甘蓝夜蛾(Mamestra brassicae L.)5龄幼虫的触杀死亡率分别为70.27%、87.50%和90.00%。种子乙酸乙酯萃取物对粘虫3龄幼虫的胃毒死亡率可达57.14%,秋季茎秆乙酸乙酯萃取物对3龄幼虫的生长发育抑制率为30.45%。     

葎草提取物对朱砂叶螨生物活性的研究

在28℃、60%～80%RH、16L∶8D的实验条件下研究了葎草乙醇和水提取物对朱砂叶螨的生物活性。结果表明,葎草乙醇提取物对朱砂叶螨有较强的触杀作用,80g/L浓度的提取物平均死亡率高达91.11%,80g/L浓度的水提物下平均死亡率51.11%;乙醇提取物对朱砂叶螨有较强的驱避作用,在浓度为10g/L的醇提物下驱避率达60%,醇提效果优于水提;乙醇提取物对朱砂叶螨成螨产卵量有较强的抑制作用,在浓度为10g/L的醇提物和水提物下,减少率分别为62.39%与47.93%。研究结果有助于朱砂叶螨的综合治理。     

甘青赛莨菪粗提物的杀虫活性研究

采用虫体浸渍法和叶碟浸渍法研究了甘青赛莨菪粗提物对粘虫、菜青虫和麦长管蚜虫的杀虫活性。试验结果表明,甘青赛莨菪叶甲醇粗提物对粘虫5龄幼虫的触杀活性最强,其次为茎和根皮甲醇粗提物,稀释5倍液的校正死亡率分别为28.09%,18.30%和17.07%。叶甲醇粗提物对4龄菜青虫的触杀活性最强,其次为茎和根皮甲醇粗提物,稀释10倍液的校正死亡率分别为66.67%,64.29%和60.00%。叶、茎和根皮甲醇粗提物对4龄菜青虫的拒食活性均很弱,对麦长管蚜具有一定的触杀活性,对棉蚜和桃蚜无触杀活性。     

白沙蒿杀虫活性初探

白沙蒿(Artemisia sphaerocephala)是典型的流动沙丘植物,非常适应干旱荒漠地区的极端气候,是沙漠荒漠化治理和恢复中优良的固沙植物之一。植物中的次生代谢物是其适应不利环境因素的重要策略之一。本研究首次开展了白沙蒿提取物对朱砂叶螨(Tetranychus cinnabarinus)和斜纹夜蛾(Spodoptera litura)幼虫的活性测试,并对受体植物油菜(Brassica campestris)、紫花苜蓿(Medicago sativa)、红三叶(Trifolium pratense)和早熟禾(Poa annua)的植物毒活性也进行了检测。结果表明,白沙蒿提取物对两种害虫均表现出具有较强的杀螨活性,但对农作物油菜和牧草红三叶、紫花苜蓿和早熟禾的生长没有明显影响。在低浓度时,还对紫花苜蓿和早熟禾的生长有一定的促进作用。浓度为333μg·m L-1时,对朱砂叶螨的触杀活性大于60%,在20μg·m L-1的浓度下对斜纹夜蛾幼虫的触杀活性大于50%,而在50和25μg·m L-1浓度下对苜蓿和早熟禾有促进作用,对油菜和红三叶的抑制率小于20%。     

灰绿黄堇提取物对粘虫的生物活性研究

采用虫体浸渍法、夹毒叶碟法等方法研究了灰绿黄堇提取物对粘虫(Mythimna separate)的杀虫活性和作用方式。结果表明,灰绿黄堇不同极性溶剂粗提物对粘虫3龄幼虫的触杀作用以甲醇粗提物最强,校正死亡率为15.5%;甲醇粗提物不同极性溶剂萃取物以氯仿萃取物触杀作用最强,校正死亡率可达87.5%,其致死中质量浓度为13.07 g/L;氯仿萃取物对粘虫3龄幼虫具有很强的生长发育抑制作用和胃毒作用,生长发育抑制率和校正死亡率分别为88.66%和91.38%。     

3种橐吾属植物提取物的杀虫抑菌活性

黄帚橐吾（Ligularia virgaurea）、箭叶橐吾（L. sagitta）和藏橐吾（L. rumicifolia）均为青藏高原东缘退化高寒草原生态系统的典型毒杂草。本研究从“变害为利”的角度出发,通过测定和对比3种植物提取物对粘虫（Mythimna separate）幼虫的生物活性、对尖孢镰刀菌（Fusarium oxysporum）菌丝生长的影响,探索其生物农药潜力开发价值。研究结果表明：3种橐吾属植物提取物对受试害虫均有较强的胃毒、触杀和拒食作用,表现为藏橐吾>黄帚橐吾>箭叶橐吾。藏橐吾提取物浓度较低时(5 mg·mL^-1),对粘虫幼虫的胃毒7 d累计校正死亡率和触杀7 d累计校正死亡率就分别在70%和50%以上;黄帚橐吾提取物浓度在10 mg·mL^-1以上时,对粘虫幼虫的胃毒7 d累计校正死亡率和触杀7 d累计校正死亡率才能达到70%和50%;而箭叶槖吾提取物在20 mg·mL^-1时对粘虫幼虫的胃毒7 d累计校正死亡率和触杀7 d累计校正死亡率仍都不超过50%。此外,浓度高于2.5 mg·mL...     

马铃薯无光干芽和花乙酸乙酯粗提物杀虫活性的研究

关于马铃薯芽和花的杀虫活性研究,国内外未见文献报道。研究马铃薯无光干芽和花的杀虫活性及其对粘虫的作用方式,可为利用无光干芽和花创制新型植物源杀虫剂提供线索和理论依据。本研究采用虫体浸渍法和夹毒叶碟法测定了庄薯3号马铃薯无光干芽和花乙酸乙酯粗提物的杀虫活性。结果表明,庄薯3号马铃薯无光干芽和花乙酸乙酯粗提物对粘虫幼虫具有很强的触杀作用,稀释5倍液的校正死亡率分别为52.0%和61.36%。无光干芽和花乙酸乙酯粗提物对粘虫幼虫具有很强的生长发育抑制作用,处理后1,2,3,4,5,6 d的生长发育抑制率分别为100%和100%,76.92%和61.54%,66.67%和59.26%,70.27%和45.95%,72.55%和49.02%,67.12%和35.62%;具有很强的麻醉作用,1 h内的麻醉率分别为68.0%和66.0%,麻醉作用的回归方程分别为Y=2.0542+3.1331X和Y=3.0114+2.3334X,苏醒中时RT₅₀分别为8.71和7.12 h;对小菜蛾、菜粉蝶、大菜粉蝶和云斑粉蝶幼虫具有很强的触杀作用,稀释5倍液(小菜蛾4倍液)的校正死亡率分别为75.0%和58.33%,87.50%和95.0%,100%和93.33%,100%和100%;对萝卜蚜均具有很强的触杀作用,稀释30倍液的校正死亡率分别高达98.52%和97.79%。     

瑞香狼毒根提取物对荞麦桃蚜的毒力及其作用机制

蚜虫是荞麦(Fagopyrum esculentum Moench)花期的主要害虫,对荞麦产量影响很大,本论文研究了不同浓度瑞香狼毒(Stellera chamaejasme L.)根提取物对荞麦桃蚜的杀虫活性以及对其体内2种靶标酶和3种解毒酶活性的影响。结果表明：瑞香狼毒根石油醚提取物对桃蚜有较强的毒杀作用,24 h对桃蚜的致死中浓度LC₅₀为1 243.7 mg·L^-1。桃蚜经提取物处理24 h后,其体内乙酰胆碱酯酶活性受到抑制,最高抑制率为21.7%;腺苷三磷酸酶活性升高,Na⁺-K⁺-ATPase和Ca²⁺-Mg²⁺-ATPase活性在提取物浓度为4 000 mg·L^-1时最大,显著高于未处理桃蚜两种酶活性,分别是未处理的12.0和1.8倍。瑞香狼毒根提取物提高了桃蚜体内解毒酶——谷胱甘肽-S-转移酶和细胞色素P₄₅₀的活性,降低了羧酸酯酶活性。综上,瑞香狼毒根石油醚提取物对桃蚜有很好的毒杀作用,提取物可...     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein