Benzophenone glycosides and epicatechin derivatives from Malania oleifera

A new benzophenone C-glycoside, malaferin A (1), and two new epicatechin derivatives, malaferin B (2) and malaferin C (3), together with five known compounds were isolated from Malania oleifera. In addition, (-)-epicatechin-3-O-benzoate (6) was isolated for the first time from a natural resource. Structures of 1-3 were determined on the basis of their spectroscopic methods, including 1D and 2D NMR techniques. All of the compounds were evaluated for anti-HIV activities.     

饲粮不同采食水平下肉羊氮沉积和尿中嘌呤衍生物排出规律的研究

本试验旨在研究饲粮不同采食水平下肉羊氮沉积和尿中嘌呤衍生物(PD)的排出规律.试验选用12只平均体重为(41.3±2.8)kg的杜寒杂交绵羊公羔,随机平均分为3组,按照自由采食、自由采食量的70％和自由采食量的40％3个干物质采食水平饲喂,试验期为12d,其中预试期7d,正试期5d.结果表明:随着饲粮采食水平的降低,营养物质消化率均显著上升(P＜0.05),粪氮和尿氮排出量均显著降低(P＜0.05),沉积氮与摄入氮之间存在线性相关(R2=0.92).尿中PD排出量和微生物氮(MN)产量均随采食水平的降低而显著降低(P＜0.05),嘌呤氮指数(PNI)与氮沉积率和氮吸收率均表现出相同变化趋势.由此可见,PD排出量与可消化有机物采食量(DOMI)以及MN产量之间均存在线性相关,相关方程分别为y=21.41X-1.81(R2=0.94)和Y=0.91X+2.57(R2=0.94);PNI能够将氮平衡和PD排出量有机结合起来,用于评价饲粮氮的利用效率.     

青蒿素及其衍生物在动物生产中的应用研究

青蒿素是一种倍半萜内酯类化合物,其特殊的过氧基团结构使其具有抗疟疾、抗菌、抗炎、抗氧化、抗寄生虫、免疫调节、缓解热应激、促进生长等作用。青蒿素及其衍生物应用于动物生产中可以替代抗生素,具有广阔的应用前景。文章对青蒿素及其衍生物的生理功能、主要提取方式及在动物生产中的应用进行论述。     

反刍动物雪尿分析：3个指数在评价营养样状态中的比较及应用

基于以往的综述和研究性文章,本文对通过尿液分析评价反刍动物营养状态的3个指数进行了讨论和比较:相对于A:C比值而言,U:C比值不能够反映不同年份动物的营养限制情况,A:C比值和U:C比值均会因随机抽样的原因导致对动物营养状态的过高或过低估计,在一些物种中A:C比值不如PD:C灵敏。并对这些指数在今后研究中的应用进行了初步探讨。     

Alternative methodologies to estimate ingestion of caecotrophes in growing rabbits

This study was carried out in order to estimate caecotrophe intake in growing rabbits by three existing procedures: caecotrophes collection after collar fitting, urinary purine derivatives (PD) excretion and microbial ¹⁵N-lysine incorporation. In a first experiment sixteen New Zealand White male rabbits were divided in three groups receiving the same diet, but supplemented with ¹⁵NH₄Cl in the first group (T₁: 6 rabbits). The second group (T₂: 6 rabbits) was also fed the labelled diet but only during the last ten days of the fattening period when animals were fitted a neck collar to prevent caecotrophy. The third group (T₃: 4 animals) received the basal diet and was used as control. In two additional trials the daily contribution to urinary excretion of endogenous purine compounds (469 ± 50.8 μmol/W^0.75) and creatinine excretion (807 ± 127.6 μmol/W^0.75) were determined. The highest estimation of microbial nitrogen recycling was obtained by the urinary PD method (0.79 ± 0.096 g/d), whereas caecotrophes collection and ¹⁵N-lysine incorporation methods showed similar values (0.49 ± 0.049 and 0.45 ± 0.015 g/d, respectively). Our results seem to indicate an overestimation of microbial nitrogen recycling in growing rabbits by PD methodology, while neck collar fitting procedure gave similar results, although more variable than microbial ¹⁵N-lysine incorporation.     

Tandem size exclusion chromatography-Polyacrylamide gel electrophoresis of humic acids

Humic acids (HAs) from four soils were fractionated by size exclusion chromatography (SEC) on Sephadex G-75. Three fractions were obtained in all humic acids, collected and assayed by Polyacrylamide gel electrophoresis (PAGE). The unfractionated HA from each soil was used as reference. Each chromatographic fraction formed one electrophoretic zone corresponding closely to one band of the reference sample with some admixture of the fractions preceding or following. The results indicate that fractionation of HAs by tandem SEC-PAGE can be successfully used for obtaining fractions of reduced polydispersity and different electrophoretic mobilities. Pyrolysis/methylation-gas chromatography-mass spectrometry of the full size preparations of HA and fractions with exactly defined molecular size and electrophoretic mobility showed a different distribution in humic components, mainly lipids, lignin derivatives and N-containing compounds.     

Dermatophytosis due to Microsporum persicolor (13 cases) or Microsporum gypseum (20 cases) in dogs

A retrospective study of 20 cases of dermatophytosis due to Microsporum gypseum and 13 cases due to Microsporum persicolor seen over an 8-year period is reported. These skin diseases are rare (1.3% of our canine case load) and pleomorphic, from localized erythematous and squamous or suppurative lesions (kerions) to extensive or generalized erythematous, alopecic, scaling, crusting and eventually papular and pustular dermatoses. Such dermatophytoses are diagnosed by fungal culture, and in some instances rapidly by dermatohistopathology with periodic acid-Schiff staining (3/3 cases of Microsporum gypseum infection and 5/7 cases of Microsporum persicolor infection). Therapy with topical and/or systemic azole derivatives (topical enilconazole, miconazole, econazole and systemic ketoconazole, respectively) was successful in all cases, with only two relapses, which were easily controlled.     

N-硝基苯基脲衍生物对油菜生长调节活性与结构相关性分析

运用量子化学方法(PM3)计算了6种标题物的结构参数,并对标题物对油菜生长调节活性与其分子右侧苯环上取代基的电子效应之间的相关性及取代基的电子效应(δ）与分子的结构参数之间的相关进行了分析,结果表明其相关性能优良．     

Bactericidal and fungicidal activity of Aspergillus ochraceus metabolites and some derivatives

The bactericidal and fungicidal activities of aspyrone and asperlactone, secondary metabolites of Aspergillus ochraceus, and some aspyrone derivatives were studied. In general, aspyrone exhibited better activity than asperlactone or aspyrone derivatives. The inhibition patterns of the assayed compounds were different. Helminthosporium monoceras was the tested mould most inhibited by the studied compounds. The comparative study of the activity of the different compounds showed that the epoxy group seems to be necessary for activity against some micro-organisms. © 1998 SCI