诱导性免疫共刺激分子转基因小鼠模型的建立

利用RT—PCR方法从人扁桃体的激活T细胞mRNA中扩增出诱导性免疫共刺激分子(ICOS)cDNA,继而将ICOS基因插入到pEGFP—N3中得到含ICOS和GFP融合蛋白的pEGFP—ICOS。将外源基因pEGF、P—ICOS注射至FVB小鼠原核中,其胚胎移植到同期发情的假孕受体产出后代,经PCR和Southern检测获得阳性转基因小鼠。试验共注射移植胚胎117枚,出生小鼠43只,检出阳性小鼠2只,该转基因已稳定遗传至F3代,说明建立了ICOS转基因小鼠模型。     

A review of tree fodder production and utilization within smallholder agroforestry systems in Kenya

Although the biological advantages in terms of animal production and improved soil fertility of the use of herbaceous legumes have been well demonstrated in Kenya and elsewhere, adoption by small-scale farmers has often been disappointing. This has led to increased research into the use of both indigenous and exotic fodder trees. In common with conventional pasture legumes, tree fodders contain high levels of crude protein and minerals and many show high levels of digestibility. They are readily accepted by livestock and presumably because of their deep-root systems, they continue to produce well into the dry season. Antinutritive factors can be a problem, however, and polyphenolics, toxic amino acids, cyanogenic glycosides and alkaloids are found in many tree species. There are abundant niches on small farms where fodder trees can be grown without affecting crop production. Although detailed management recommendations are lacking, guidelines exist with regard to appropriate cutting heights and harvesting frequencies. In the Embu region, it has been estimated that three kg of fresh fodder of Calliandra calothyrsus has the same effect on milk production as one kg of commercial dairy meal. Up to about 500 trees (250 m of hedgerow) will produce enough fodder to supplement one dairy cow for a complete lactation. The tree fodder can either replace the concentrate without loss of yield, or it can complement it to produce more milk. It is being enthusiastically adopted by small-scale farmers, many of whom are starting to produce their own seed. Other tree species are now being studied in order to avoid over-reliance on a single fodder species. This revised version was published online in August 2006 with corrections to the Cover Date.     

微波加热软化木材的弯曲工艺研究

研究了微波加热水曲柳试件进行弯曲的工艺及其弯曲工艺参数与产品质量的关系。研究结果表明：该弯曲工艺可行;最佳工艺条件为木材含水率60％,微波加热功率400W,微波加热时间2.5min;该方法较传统生产方式的生产率明显提高。     

Nitrate leaching loss following application of organic manures to sandy soils in arable cropping.

Abstract. Experiments were set up at two sites to measure nitrogen (N) leaching loss from applications of separated pig/cattle slurry and cattle farmyard manure(FYM), during winters 1990/91–1993/94 (site A) and from broiler litter and FYM, during winters 1990/91–1992/93 (site B). The manures were applied at a target rate of 200 kg ha^-1 total N during the autumn and winter to overwinter fallow or top dressed onto winter rye. The total N in leachate was calculated from leachate N concentrations, in samples collected using ceramic cups buried at 90 cm, and an estimate of drainage volume. Nitrogen losses were greatest following manure applications in September, October and November but losses following applications in December or January were not significantly elevated above those from untreated controls. Losses were consistently lower from FYM than from broiler litter or separated slurry. The presence of a cover crop (winter rye) significantly reduced overall N leaching compared with the fallow, but only reduced the manure N leaching losses at one site during one winter when a high proportion of drainage occurred late. The incorporation of a nitrification inhibitor (DCD) with manures applied in October did not significantly reduce the manure N leaching.     

长期施用化肥和农家肥对土壤化学性质和作物产量的影响

A long-term fertiliztion experiment was carried out in an experimental field in Lyczyn near Warsaw,Poland.Application ofmineral fertilizers ,especially Nfertilizer with and without farmyard manure accel-erated the eacidification process of the soil.Application of 1.6 t CaO ha^-1 every four years was essential to maintenance of the soil pHKCl at 5.5-6.6 and base saturation degree above 60% Application of 50 t farmyard manur ha^-1 every 4 years,whih contained 46 kg P and 240 kg K,was sufficient to maintain boh the K and P fertility of the soil.Besides,it was beneficial to alleviating soil acidifcation. As a result of long-term unbalanced fertilization,yield responses to N,P and K fertilizers incereased significantly with time.the efficiency of N from farmyard manure was found to be comparable to that of N fertilizer during 1988-1991.     

天然沸石对猪场厌氧发酵液中氨氮吸附作用的试验研究

为达到利用人工湿地处理高氨氮污水的目的,采用天然沸石作为人工湿地基质,对比研究了天然沸石对NH4Cl溶液和猪场厌氧发酵液中氨氮的等温吸附特征、吸附动力学过程,考察了吸附时间、氨氮初始浓度、沸石用量对沸石吸附氨氮的影响。结果表明,Freundlich方程较Langmuir方程能更为准确地描述天然沸石对两种水质中氨氮的等温吸附特征;在两种水质中,单分子层饱和吸附量分别为16.20mg·g-1和3.85mg·g-1。天然沸石对氨氮的吸附作用受吸附时间、氨氮初始浓度及沸石用量影响较大,在两种水质中,沸石对氨氮的吸附过程在0～8h内均随时间显著上升,到48h时达到吸附平衡;当采用NH4Cl溶液时,初始氨氮的浓度由10mg·L-1增加到500mg·L-1时,平衡吸附量由0.19mg·g-1增加到5.91mg·g-1;当采用猪场厌氧发酵液时,初始氨氮的浓度由39.4mg·L-1增加到502.9mg·L-1时,平衡吸附量由0.63mg·g-1增加到3.20mg·g-1;增加沸石用量,可以提高氨氮的去除率,但单位质量沸石的氨氮吸附量随之降低。准二级动力学可以很好地描述天然沸石吸附两种水质中氨氮的动力学过程;由模型得出的天然沸石...     

固相萃取–高效液相色谱测定水稻中的洛克沙胂

通过对超声提取法中提取剂、固相萃取中淋洗液和洗脱剂、高效液相色谱中流动相的筛选,建立固相萃取–高效液相色谱定量检测水稻中洛克沙胂的方法。所建方法为：样品先经0.05 mol/L NaOH+20 g/L K2HPO4超声提取;再利用活化后的固相萃取小柱,依次采用1.5 mL 0.05 mol/L乙酸钠–甲醇溶液(pH=7)和1.5 mL甲醇淋洗及体积分数为13%的甲酸–甲醇溶液洗脱;最后利用以含0.3%甲酸的0.05 mol/L磷酸二氢钾溶液和甲醇(体积比80∶20)为流动相的高效液相色谱进行定量分析;该方法在洛克沙胂质量浓度为0.01~10.00 mg/mL时线性关系良好,相关系数大于0.999,检测限和定量限分别为20、67 ng/kg;洛克沙胂在水稻根、茎、叶、壳、米中的加标回收率分别为80.0%~87.2%、74.0%~80.6%、80.0%~83.7%、81.0%~90.0%和83.2%~92.7%,相对标准偏差分别为2.2%~5.9%、2.4%~4.6%、2.0%~2.6%、3.6%~5.7%和3.2%~5.5%。     

家畜基因组遗传多态标记—微卫星标记研究进展(下)

３微卫星标记的应用自微卫星被发现以来就受到了家畜遗传育种家们的高度重视,并且充分认识到了把它作为畜种的基因组变异研究所具有的巨大的潜在价值。现在它已被十分成功地作为富含信息、又容易获得的基因标记,广泛用于构建物种的遗传连锁图,基因鉴定（基因诊断）、物...     

Soil sulphur status following long-term annual application of animal manure and mineral fertilizers

 In agricultural systems with low S inputs, crops rely on the release of S from organic forms in the soil. In the Askov long-term experiments, started in 1894 on both sandy and loamy soils, soil S status following long-term application of animal manure and mineral fertilizers was investigated in the growing season of 1995. In a field trial with oil-seed rape (Brassica napus, L.) soil analysis, leaf tissue analysis, yield and S removal in plant material was used to characterize differences in availability of soil S. One half of all plots received 63 kg S ha^–1 as gypsum. Long-term fertilization with animal manure or NPK fertilizer increased the content of soil organic C in both soils and of organic S in the sandy soil compared with unfertilized plots. Although dry matter yields were unaffected, the S uptake in harvested crop parts increased considerably after S application. The amounts of N and S in harvested seeds and straw were closely related, but the N : S ratio decreased when S was applied. Soil and plant analyses both indicated that critical levels of S concentrations were reached, and that S application was capable of raising S concentrations well above the critical level. Because no additional mineralization from residual organic S took place, it was concluded that the residual S effect from long-term annual applications of animal manure or mineral fertilizers did not significantly increase the level of soil S available for crops with a short growing season, such as oil-seed rape. Received: 9 January 1998