Mn2+和CO2+胁迫对舞毒蛾幼虫营养和抗氧化力的影响

[目的]为了明确舞毒蛾幼虫对Mn^2+和Co^2+胁迫的响应机制。[方法]采用0.40 mmol·g^-1 Mn^2+和0.83 mmol·g^-1 Co^2+的两种混合饲料分别喂食舞毒蛾4龄幼虫,测定了Mn^2+和Co^2+(LC30)对舞毒蛾4龄幼虫体质量、营养取食情况、营养成分含量及总抗氧化力。[结果]与对照组相比较,其取食量、虫粪量、体质量增长量均显著降低;Mn^2+处理组可溶性蛋白含量降低33.76%,碳水化合物含量降低57.56%,海藻糖含量降低64.05%,脂质含量降低27.77%;处理组可溶性蛋白含量降低47.46%,碳水化合物含量降低59.45%,海藻糖含量降低59.16%,脂质含量降低33.71%;Mn^2+处理组总抗氧化力增加28.25%,处理组总抗氧化力增加82.54%.表明Mn^2+和Co^2+对舞毒蛾幼虫取食量、虫粪量、体质量增长量、可溶性蛋白含量、碳水化合物含量、海藻糖含量、脂质含量均有显著的抑制作用,对其总抗氧化力有显著的促进作用。[结论]舞毒蛾幼虫是主要通过提高自身抗氧化力来应对重金属的胁迫,从而提高自身对重金属的抗性。     

双核磺化酞菁钴-表面活性剂薄膜电极对巯基乙醇的电催化氧化

采用双核磺化酞菁钴-DDAB表面活性剂修饰电极在碱性溶液中利用Co（Ⅱ）/Co（Ⅲ）电对催化氧化巯基乙醇.结果显示：在pH为10～13.5的溶液中,巯基乙醇的催化电位为-50～-60 mV,在pH为11时,催化效果最好.当巯基乙醇浓度在5.0×10-3～7×10-2mol/L时,氧化峰电流随浓度线性增加;当浓度为7×10-2mol/L,扫速为100～700 mV/s时,峰电流与扫速平方根成正比,表明反应为扩散控制过程.     

Influence of Different Ratios of Cobalt and Copper Supplementation on Vitamin B12 Status and Nutrient Utilization in Sheep

The present study is aimed to investigate the effects of different ratios of cobalt （Co） and copper （Cu） supplementation on vitamin B12 status and nutrient utilization in sheep. Twenty wether lambs with an average weight （22.9 ± 0.8） kg were randomly divided into five groups and fed with the control diet which was supplied with 0.3 mg kg^-1 DM （dry matter） of Co to the basal diet, and four supplemental diets which were supplied either 0.3 or 0.6 mg kg^-1 DM of Co and 10 or 20 mg kg^-1 DM of Cu to the basal diet, respectively for 8 wk. The supplementation of Co and Cu with different levels improved plasma vitamin B12 concentration which was increased with feeding time, but stable after 6 wk. Vitamin B12 status was accounted for Co intake with no combined effects by supplementation of different levels of Co and Cu. The plasma concentrations of methylmalonic acid, homocysteine, folic acid, and glucose did not show the consistent results with plasma vitamin B12, which was considered to be resulted from Cu action. Addition of Co and Cu with different levels had no influence on digestibility of dry matter （DM）, organic matter （OM）, crude protein （CP） and nitrogen free （NFE）, and N metabolism （P〉 0.05）, but the digestibility of fat and fibre （P〈0.01） was enhanced by supplementation of 0.3 mg kg^-1 DM of Co and 20 mg kg^-1 DM of Cu. In conclusion, the supplementation of Co and Cu with different levels has no influence on vitamin B12 status. The optimum ratio of Co and Cu in diet could enhance the nutrient utilization.     

ORIGINAL ARTICLE: Intravenous injections of cobalt reduce fatty acid desaturation products in milk and blood of lactating cows

The objective of this study was to determine whether intravenous infusion of Co affects levels of fatty acid desaturation products in bovine milk. Six cows were assigned to two replicated 3 × 3 Latin squares with 14‐day periods. Treatment occurred on days 1 to 5 and depuration occurred on days 6–14. Two treatments were tested, the first consisting of per os supplementation of 3.5 g Co daily in the form of Co acetate and the second consisting of intravenous injection of 175 mg Co daily in the form of Co acetate diluted in saline solution. The third treatment was a control. Both Co treatments decreased cis‐9 18:1 levels from approximately 18 to 14 g/100 g fatty acids, and increased 18:0 levels from 11 to 17 g/100 g fatty acids in milk fat (p < 0.001). The proportions of cis‐9 10:1, cis‐9 12:1, cis‐9 14:1, cis‐9 16:1 and cis‐9 17:1 decreased (p < 0.001), whereas 17:0 and trans‐11 18:1 increased (p < 0.001). In blood plasma, levels of cis (6,9,12) 18:3 (p < 0.001) and cis (8,11,14,17) 20:4 (p = 0.008) decreased after both the Co treatments. It is concluded that intravenous supply of Co reduces levels of fatty acid desaturation products in both bovine milk and blood.     

火焰原子吸收分光光度法测定土壤中痕量钴

分析测定土壤中痕量钴的含量对于土壤污染调查具有切实意义。用火焰原子吸收分光光度法测定土壤中的重金属钴,通过对标准土样的测定结果表明,该方法容易操作、准确、可靠。     

高效桐油催干剂的制备及其催干性能研究

考察了4种催干剂异辛酸稀土(REI)、异辛酸钴(CI)、高效催干剂M2203和CQ-150B单独或配合使用时对桐油和聚合桐油催干性能的影响,结果表明:10℃时聚合桐油黏度为15 520 mPa·s,比桐油黏度(160 mPa·s)有明显增加;20℃时聚合桐油的干燥时间为72 h,较桐油干燥时间(168 h)明显缩短。异辛酸稀土和异辛酸钴单独使用时,催干效果明显低于M2203和CQ-150B;0.6%的异辛酸稀土与0.010%的异辛酸钴复配的复合催干剂,催干桐油的表干时间、实干时间分别为2和2.5 h,硬度等级为4H,附着力等级为1级;催干聚合桐油的表干时间、实干时间分别为0.67和1 h,硬度等级为5H,附着力为1级。与高效催干剂M2203和CQ-150B相比,复合催干剂色泽浅,与桐油相容性好。FT-IR和TG表征分析表明:复合催干剂催干制备的桐油漆膜交联度高、热稳定性好,该复合催干剂是一种性能优良的桐油催干剂。     

日粮钴铜比例对肉用绵羊维生素B12营养状况及养分代谢的影响

 【目的】研究不同比例的日粮钴铜对肉用绵羊维生素B12营养状况及营养物质消化代谢的影响。【方法】选取20只健康、体重相近（22.9±0.8）kg的小尾寒羊×无角陶赛特杂交一代羯羊,随机分为5组,定量饲喂5种不同日粮,即对照组日粮、4种不同比例的钴铜（0.3﹕10、0.3﹕20、0.6﹕10和0.6﹕20）日粮,试验期8周,试验中期进行消化代谢试验,同时每两周采血样,用电化学发光法、气相色谱法及荧光偏振免疫法测定血浆维生素B12及叶酸含量、甲基丙二酸和同型半胱胺含量。【结果】肉羊日粮添加不同比例的钴铜,血液维生素B12的含量随饲喂时间的延长而增加,6周后趋于稳定。钴水平较高的后两组显著高于其它3组（P＜0.01）,血液维生素B12含量主要取决于钴的摄入量,钴和铜无协同效应。血浆甲基丙二酸和血糖含量随日粮钴铜比例增加而呈下降和上升趋势,同型半胱胺水平无变化,叶酸含量在0.6﹕20 mg?kg-1钴铜添加组显著升高（P＜0.05）。钴和铜的添加比例对DM、OM、CP、NFE表观消化率及氮代谢无影响（P＞0.05）,而配比为0.3﹕20时显著促进脂肪和纤维的消化（P＜0.01）。【结论】肉羊日粮中钴和铜的添加比例对维生素B12营养状况无影响,但适宜配比有利于营养物质的消化代谢。     

Regulators of ethylene biosynthesis or activity as a tool for reducing susceptibility of host plant tissues to infection by Botrytis cinerea

Several compounds were tested for their ability to reduce development of grey mould on rose, tomato, pepper, eggplant, French bean andSenecio sp. Removal of ethylene from the atmosphere surrounding rose flowers, or leaves of tomato and pepper, by potassium permanganate, resulted in slower grey mould development. Inhibition of ethylene activity by 2,5-norbornadiene controlled disease on all crops but tomato. Carbon dioxide controlled grey mould on roses, but the potential for use of these agents is in doubt. Inhibitors of ethylene biosynthesis such as aminooxyacetic acid (AOA), cobalt ion, the uncoupler 2,4-dinitrophenol and the radical scavenger salicylic acid were differentially effective in controlling the disease in the various hosts. Fifty mM AOA reduced grey mould on rose flowers by up to 97% when flowers were partially aerated. AOA was not phytotoxic on the tested rose cvs Golden Times and Jaguar. Combinations of ethylene absorption, inhibition of ethylene activity and ethylene biosynthesis did not result in better control as compared with the disease reduction ability of the compounds alone, tested on the various hosts. Application of benzyladenine, which reduces the host responsiveness to ethylene, resulted in 39–99% grey mould reduction in rose flowers and in leaves of tomato andSenecio sp. but was not effective on pepper or eggplant. Manipulation of ethylene presence and of host plant susceptibility to grey mould is discussed.Contribution from The Agricultural Research Organization, Bet Dagan, Israel, No. 3270-E, 1991 series.     

Serum Vitamin B12 Levels in Omani Goats

Blood and faecal samples were studied from 200 Omani goats of both sexes and various age groups, within five different regions in Oman. Survey questionnaires were undertaken on each goat. The serum vitamin B12 values ranged from 105 to >2000 pg/ml, with a mean value of 723.1 pg/ml and a 95% confidence interval of 61-1507 pg/ml. Kids in the age group 1-3 months showed significantly lower levels of serum vitamin B12 than the older animals. Varying levels of serum vitamin B12 were found in different regions of Oman and on farms within the same region. Goats maintained on commercial feed showed higher levels of serum vitamin B12 than those maintained on pasture or fed on household leftover food, as commonly practised in Oman. Coccidial counts were highest in animals with lower levels of serum vitamin B12. The results of this study indicate that there is a wide range of serum vitamin B12 levels in Omani goats and suggests that younger animals, with lower levels of serum vitamin B12, might be more susceptible to vitamin B12 deficiencies than older animals.     

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