施氮对苦豆子生物性状和生物量积累动态的响应

研究了不同氮肥水平(0、50、100、150、200 kg/hm2)对苦豆子Sophora alopecuraides生物性状和生物量积累动态的影响,旨在探索人工栽培苦豆子的施氮量,从而提高苦豆子栽培的生物产量.结果表明:施氮对其株高、单株茎数均有增加效果,增施氮肥对各时期的株高增加效果明显,特别是在7-8月,茎的生长速率明显高于对照,施氮肥对根直径的增加效应不显著;氮肥对单株根鲜质量和干质量增加效应显著,施用氮肥使茎叶鲜质量和干质量开始下降的时期推迟.100和150 kg/hm2施肥处理对生物量的增加幅度明显高于对照.     

氧化苦参碱和苦参碱含量在苦参生长发育过程中的动态变化

苦参Sophora flavescens为多年生草本或灌木,其根入药.为了揭示氧化苦参碱(Oxmatrine,OMT)和苦参碱(Matrine,MT)在苦参体内代谢转化规律及两者之间的关系,为人工栽培苦参提供理论依据,运用高效液相色谱(HPLC)技术对苦参根、茎、叶、种子生长发育过程中氧化苦参碱和苦参碱含量动态变化进行了全面的研究.结果表明.根和成熟种子中氧化苦参碱和苦参碱含量最高,苦参碱主要分布在幼嫩的叶和茎中,而在成熟和衰老的叶和茎中苦参碱则转化为较为稳定的氧化苦参碱.在根和种子等贮藏器官中则主要以氧化苦参碱的形式贮存,并且根和种子中氧化苦参碱和苦参碱含量以及相同器官2种生物碱含量变化呈现互补的特点,由此推断,叶中形成的氧化苦参碱和苦参碱在向根和种子运输分配时受其生长竞争的影响,它们之间可以相互转化.     

苦豆子赖氨酸脱羧酶基因克隆与表达分析

赖氨酸脱羧酶(lysine decarboxylase,LDC)基因是苦豆子中氧化苦参碱(oxymatrine,OMA)生物合成的第一个关键酶基因。根据近缘物种苦参的赖氨酸脱羧酶基因设计特异引物,同源克隆法克隆了苦豆子赖氨酸脱羧酶基因的蛋白质编码区序列,全长1368 bp,命名为Sa-LDC,GenBank登录号为KM249871。生物信息学分析表明Sa-LDC编码区序列无内含子,与苦参和狗苦参的LDC序列一致性均达到97%;属于Ⅲ型5-磷酸吡哆醛依赖酶[type Ⅲ pyridoxal 5-phosphate (PLP)-dependent enzymes,PLPDE-Ⅲ]超基因家族,功能活跃。Sa-LDC编码455个氨基酸残基,其编码的肽链相对分子质量49.14 kD,理论等电点5.63,无信号肽和跨膜结构;在其氨基酸序列中具有产喹诺里西啶生物碱的特征性保守位点Phe³⁴⁰;系统进化树将苦豆子与其他产喹诺里西啶类生物碱的植物聚为一类。qPCR和HPLC检测显示,苦豆子赖氨酸脱羧酶基因的表达和氧化苦参碱的积累均受干旱胁迫的影响,且基因的表达量与氧化苦参碱的积累呈正相关关系。     

复方苦豆子灌注液总生物碱含量测定方法的建立

为建立复方苦豆子灌注液总生物碱含量的测定方法,采用酸性染料比色法,以氧化苦参碱为对照品进行含量测定,检测波长420 nm 的吸光度。结果显示,氧化苦参碱在2．0μg／mL～10μg／mL 范围内与吸光度呈良好线性关系,回归方程为 A＝0．0058C＋0．1116,r＝0．9992,氧化苦参碱的平均回收率为99．6％,RSD＝2．20％（n＝5）。该方法简便灵敏、准确可靠,可作为复方苦豆子灌注液的质量控制方法。     

四川丘陵地区桑园合理施氮方案的研究

针对四川丘陵地区桑园偏施和过量施用氮肥的问题,设置0、120、240、360、480 kg/hm2尿素共5个施氮量试验组,通过比较与分析不同试验组桑叶产量和部分品质性状成绩,建立不同生产目的桑园施氮效应函数,提供合理的施氮方案。试验结果表明,少施或过量施氮都会降低桑叶产量及桑叶中营养活性物质的含量和桑叶营养活性物质的产量。240 kg/hm2的桑园施氮量能显著提高桑叶营养活性物质的含量;360 kg/hm2的桑园施氮量能显著提高桑叶产量及桑叶营养活性物质的产量。依据分别建立的桑园施氮量与桑叶产量、桑叶中的1-脱氧野尻霉素(DNJ)含量、桑叶DNJ产量的肥料效应函数,推荐以生产养蚕用叶为目的的桑园最佳施氮量为360 kg/hm2,以提高桑叶DNJ含量和产量为目的的桑园最佳施氮量分别为299.56 kg/hm2和294.72 kg/hm2。     

氮磷配施对生长1年苦参的影响

纯氮(N)施用量设0(对照)、38、75、113kg/hm24个水平,磷(P2O5)施用量设0(对照)、23、45、90kg/hm24个水平,二因素随机区组设计,研究氮、磷对苦参Sophora flavescens苗生长的影响以及二者的互作效应。结果显示:氮、磷对生长1年苦参生长有显著促进效应,氮和磷互作效应显著。高施氮量(113kg/hm2)和低施磷量(23kg/hm2)配合时根芽数、苗鲜质量、根鲜质量、根干质量、茎叶鲜质量、茎叶干质量最高,依次较对照增加95.6%、57%、57.6%、50.6%、60.1%和41.5%(P0.05),中低施氮量(38和75kg/hm2)与较高施磷量(45kg/hm2)配合时次之,与对照差异显著;根干鲜比和根干质量/总干质量在各施氮量下随施磷量增加;施氮量113kg/hm2和施磷量23kg/hm2配合时根直径和木部直径最大,较对照增加24.9%、20.2%(P0.05);氮和磷对皮部厚度增加效应不显著;施氮量113kg/hm2和施磷量23kg/hm2配合时单株小叶数、小叶面积和单株叶面积最大,分别较对照增加37.6%、40.2%和83.9%(P0.05)。结果表明:氮、磷对生长1年苦参的生长有显著促进效应,氮磷互作效应也均达显著水平。施氮量113kg/hm2与施磷量23kg/hm2配合、施氮量38和75kg/hm2与施磷量45kg/hm2配合时能获得较高苦参苗产量,是生长1年苦参适宜的施肥量。     

氮肥对苦参生长和生物总碱的效应

对苦参进行驯化栽培是解决其供需矛盾的主要途径,也是保护生态环境最有效的措施。本试验研究氮肥对苦参生长、生物总碱含量和生物总碱产量的效应。采用盆栽试验,施纯氮量设0,50,100,150和200 mg/kg五个水平,完全随机设计。结果表明,施用氮肥对苦参生长以及苦参总碱含量均有显著促进效应。各施氮处理根干重均与对照差异显著,当施纯氮150 mg/kg时根干重最高,比对照增加42％;根直径随施氮量提高呈增加趋势,当施纯氮150 mg/kg时根直径最大,比对照增加21.1％;叶绿素总含量在施纯氮100 mg/kg时最高,比对照增加33.8％;苦参总碱含量在施纯氮100 mg/kg时最高,比对照增加35.7％;单株苦参总碱产量在施纯氮150 mg/kg时最高,较对照增加90.5％。氮对根干重增加效应主要是由于根直径增加引起根体积增加所致,苦参叶片中叶绿素含量随施氮量增加有利于苦参总碱含量提高。     

氮肥水平对多花黑麦草产量和品质的影响

以"长江2号"、"特高"、"F4N"3个多花黑麦草品种为材料,研究不同氮肥水平对多花黑麦草产量和品质的影响。结果表明,多花黑麦草的株高随施氮量的提高显著增加(第2茬除外);各品种前三茬的产量均随施氮量的增加而增加,但300kg/hm2与450kg/hm2施氮水平下的产量差异不显著(第2茬除外),二者均显著高于150kg/hm2施氮水平的产量。多花黑麦草的粗蛋白(CP)和粗脂肪(EE)含量均随施氮量的增加而增加,各处理间CP含量差异极显著。可溶性碳水化合物(WSC)、酸性洗涤纤维(ADF)和中性洗涤纤维(NDF)含量均随施氮量的增加而降低,且各氮肥水平下的WSC含量差异极显著,中、高施氮水平下的NDF含量均极显著低于低氮水平。施氮量及品种与氮肥水平互作效应对多花黑麦草的CP、NDF和ADF含量的影响极显著。因此,从产量和品质及肥料成本综合考虑,3个品种多花黑麦草均以施用300kg/hm2纯氮较好,"长江2号"多花黑麦草在该区的表现优于"特高"和"F4N"。     

施氮量对青藏高原燕麦产量和品质的影响

研究了不同施氮量对燕麦产量和品质的影响,结果表明:施氮对燕麦产量和品质影响显著,随着施氮量的增加,其栽培学性状、产量及产量构成均发生变化。施氮水平与株高、茎粗、种子蛋白质含量之间呈显著的线性回归关系(R=0.9360,P<0.01;R=0.9830,P<0.01;R=0.8968,P<0.01),而与产量构成、草产量、种子产量之间呈显著的二次回归关系(P<0.01)。施氮量60kg/hm2时,种子产量达到最高4358.5kg/hm2;草产量达到最大值时的施氮量为75kg/hm2,草产量为22820kg/hm2(干重)。     

苦豆子生物碱对奶牛乳房炎致病菌体外抗菌活性的研究

为进一步研究苦豆子生物碱对奶牛乳房炎致病菌的体外抗菌活性,选取金黄色葡萄球菌、大肠杆菌和无乳链球菌三种奶牛乳腺炎病原菌,采用苦豆子总碱、氧化苦参碱、氧化槐定碱、槐定碱等4种苦豆子生物碱进行药物敏感度试验,以试管二倍稀释法测定其最小抑菌浓度(MIC).结果表明:苦豆子总碱与槐定碱对引起奶牛乳腺炎的三种病原菌金黄色葡萄球菌、无乳链球菌及大肠杆菌均有相似的抑菌活性,其中最为敏感的为无乳链球菌,MIC为3.125 ～ 6.25 mg/mL,其次为大肠杆菌与金黄色葡萄球菌,MIC为6.25 ～ 12.5 mg/mL.氧化苦参碱与氧化槐定碱表现较弱的抑菌活性.研究为苦豆子生物碱用于奶牛乳房炎的预防与治疗提供了依据.     

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.     

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.     

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.     

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