鸡粪的施用对薄皮甜瓜果实糖积累及糖代谢相关酶活性的影响

为了探讨鸡粪以及鸡粪与尿素配施对薄皮甜瓜果实糖积累及糖代谢相关酶活性的影响,本试验以薄皮甜瓜DX108为试验材料,以尿素为氮源的处理为对照(CK),研究了相同施氮量条件下,鸡粪与尿素配施(A)以及鸡粪(B)对甜瓜果实葡萄糖、果糖和蔗糖含量的影响,分析了蔗糖磷酸合成酶(SPS)、蔗糖合成酶(SS,蔗糖合成与分解方向)、酸性转化酶(AI)和中性转化酶(NI)的活性。结果表明,与CK相比,B、A明显促进了果实中果糖、蔗糖及葡萄糖积累,尤其是显著增加了成熟果实中这3种糖的含量。相关性分析表明,CK的甜瓜果实蔗糖积累与AI活性呈显著负相关,葡萄糖与SPS和SS(蔗糖合成酶)合成方向酶活性呈显著正相关;A和B果实中蔗糖、葡萄糖和果糖积累(除B中葡萄糖积累)与SPS、NI活性呈显著或极显著正相关,与SS分解方向酶活性呈极显著负相关,而A果实中葡萄糖积累与SPS和NI活性呈极显著正相关。综上所述,A和B提高了果实中SPS、NI活性,降低了SS分解方向酶活性,进而促进了糖的积累。本研究结果为有机肥替代化学氮肥在甜瓜生产上的应用提供了理论依据。     

炭肥比和膨润土粘结剂对炭基肥颗粒理化及缓释特性的影响

为探究炭肥比和膨润土粘结剂对生物炭基肥理化及缓释特性的影响,以生物炭为基底,分别制备了炭肥比1:4,膨润土粘结剂质量分数为20%、15%、10%、5%和粘结剂质量分数10%,炭肥比为1:6、1:5、1:4、1:3的柱状尿素和氯化钾生物炭基肥颗粒,分析了生物炭基肥颗粒的理化及缓释特性。结果表明,在炭肥比为1:4条件下,膨润土粘结剂质量分数越高,生物炭基肥微观结构越紧密,力学和缓释特性越好,质量分数为20%时,氯化钾和尿素生物炭基肥平均抗压强度分别为286.78和281.27 N,前3天养分淋出率分别为45.53%和36.87%。在膨润土粘结剂质量分数为10%条件下,炭肥比越高,生物炭基肥缓释性能越好,炭肥比为1:3时,氯化钾和尿素生物炭基肥前3天养分淋出率分别为42.06%和40.32%。同时,氯化钾生物炭基肥表面孔隙先增后减,炭肥比为1:6和1:3的平均抗压强度分别为271.25和282.42 N。尿素生物炭基肥内部结构中孔隙变多,炭肥比为1:6时,平均抗压强度为最大值267.84 N。综合考虑,满足中等肥料浓度要求时,膨润土粘结剂质量分数为20%、炭肥比为1:4或膨润土粘结剂质量分数为10%、炭肥比为1:3的生物炭基肥成型配方较优。     

改性尿素追施对冬小麦和夏玉米季氮素挥发和淋溶的影响

以NBPT(N-丁基硫代磷酰三胺)和DMPP(3,4-二甲基吡唑磷酸盐)为复合抑制剂,利用转鼓喷涂工艺,开发出新型复合型抑制剂涂覆尿素肥料,采用扫描电镜和能谱仪分析其涂覆效果。通过田间试验系统对比评价了追施不同氮肥对调控氮素的特征效果。试验设置5个处理:(1)不施氮肥(CK);(2)农民习惯追施尿素(CU);(3)优化追施尿素(CUU);(4)优化追施抑制剂涂覆尿素(CUY1);(5)优化追施抑制剂涂覆尿素(CUY2)。在夏玉米喇叭口期、冬小麦拔节期追施氮肥后的15天内进行田间原位连续动态观测。电镜和能谱结果表明,复合抑制剂均匀涂覆于尿素表面,形成薄而致密、光滑的涂覆层,该涂覆层均匀分布有磷和硫2种元素,表明复合抑制剂与尿素已有效结合。田间试验结果表明,在同等优化施氮量下与普通尿素相比,夏玉米和冬小麦季追肥后CUY1和CUY2处理氨挥发分别降低55.19%,32.15%和52.46%,39.43%。夏玉米季追肥后,0-20 cm土层CU、CUU处理土壤硝态氮含量于第5天达到峰值,到后期已显著低于CUY1、CUY2处理,CUY2处理稳定硝态氮的效果更好。冬小麦季追肥后,0-20 cm土壤硝态氮含量CU、CUU处理分别在第5,3天达到峰值,CUY1、CUY2处理于第11天达到峰值后,硝态氮含量已显著高于相同施氮量的CUU处理。在保证产量和净收益的同时,抑制剂涂覆尿素显著降低了追施氮素的氨挥发和淋溶损失浓度,其中冬小麦季CUY1处济效益较好,夏玉米季CUY2调控氮素的效果最佳,减少向下淋溶的效果明显。     

Application of urease inhibitor improves protein composition and bread‐baking quality of urea fertilized winter wheat

Background: Nitrogen losses is an economic problem for wheat production and a high risk to the environment. Therefore, improved N fertilizer management is a key to increasing the N efficiency and minimizing N losses. To increase N efficiency, enhanced fertilizers such as urea combined with urease inhibitor can be used. Aims: The aim of present study was to evaluate the effects of different N forms on grain storage protein subunits in winter wheat and to examine whether the observed changes correlate with parameters of baking quality. Methods: The investigation was performed over two consecutive years at two locations in Germany. Protein subunits were analyzed by SDS‐PAGE. Results: Protein concentrations were similarly increased after fertilization with ammonium nitrate and urea + urease inhibitor. Analysis of the individual storage protein fractions indicated that both fertilizers specifically enhanced ω‐gliadins and HMW glutenins, but the effect was more pronounced in the ammonium nitrate treatment. Application of urea + urease inhibitor had greater influence on the protein composition and resulted in higher specific baking volume as well as the best fresh keeping ability, in comparison with urea treatment. Conclusion: Considering that the urea + urease inhibitor treatment resulted in almost comparable improvements of NUE and baking quality, with the additional benefit of reduced N losses in combination with easy handling, urea + urease inhibitor can be recommended as a viable alternative to both urea alone and ammonium nitrate treatments. This opens up an opportunity for the reduction of N loss in wheat production when use of urea is preferred.     

草鱼TAB1蛋白的原核重组表达及其抗体制备

为了制备草鱼重组TAB1蛋白(rCiTAB1)及其特异性抗体,首先以草鱼头肾组织c DNA为模板,PCR扩增Ci TAB1基因全长序列,并依次构建重组克隆质粒p MD19-T-Ci TAB1与重组表达质粒pET-32a-Ci TAB1。该重组表达质粒经0.5 mmol·L~(-1) IPTG,37℃诱导表达12 h后获得以包涵体形式表达的重组CiTAB1蛋白(rCiTAB1)。然后,采用3种不同方法对包涵体蛋白进行变性,发现与高浓度尿素直接变性法和洗涤后尿素变性法相比,洗涤后梯度尿素变性法处理后的蛋白纯度最好,经透析复性后得到浓度为2 mg·mL~(-1)的r Ci TAB1。最后,将rCiTAB1蛋白与白油佐剂及免疫增强剂混合,室温下混合1.5h乳化成免疫原,3次免疫新西兰大白兔制备兔抗CiTAB1抗体,经间接ELISA方法和免疫琼脂双向扩散试验测得免疫后第33天血清中特异性抗体的效价分别为1∶1 048 576和1∶16。Western blot检测到一条分子量约为72 kDa的特异性条带,表明该抗体能特异性识别r Ci TAB1蛋白。研究结果为后续深入研究CiTAB1蛋白功能提供了物质基础。     

Influence of race and crossbreeding on casein micelles size

Casein (CN) micelles are colloidal aggregates of protein dispersed in milk, the importance of which in the dairy industry is related to functionality and yield in dairy products. The objective of this work was to investigate the correlation of milk CN micelles diameter from Holstein and Zebu crossbreds with milk composition (protein, fat, lactose, total and nonfat solids and milk urea nitrogen), somatic cell count (SCC), age, lactation stage and production. Average casein micelles diameters of milk samples obtained from 200 cows were measured using photon correlation spectroscopy and multiple regression analysis was used to find relationship between variables. CN micelle diameter, SCC and nonfat solids were different between animals with different Holstein crossbreed ratios, which suggests influence of genetic factors, mammary gland health and milk composition. Overall, results indicate the potential use of CN micelle diameter as a tool to select animals to produce milk more suitable to cheese production.     

Hypoglycemic effect of lupin seed γ-conglutin in experimental animals and healthy human subjects

A lupin seed γ-conglutin-enriched preparation was tested in a glucose overload trial with both murine models and adult healthy volunteers. The results with rats showed a dose-dependent significant decrease of blood glucose concentration, which confirmed previous findings obtained with the purified protein. Moreover, three test-product doses equivalent to 630, 315, and 157.5 mg γ-conglutin, orally administered 30 min before the carbohydrate supply, showed a relevant hypoglycemic effect in human trials. Insulin concentrations were not significantly affected. The general hematic parameters did not change at all.This is the first report on the glucose-lowering effect of lupin γ-conglutin in human subjects.     

增强剂对粉状脲醛树脂合成的影响

研究了增强剂对脲醛树脂性能的影响。通过实验得出，复合型增强剂对提高胶的胶合强度，提高软化点（软化温度迭120℃以上），降低游离甲醛方面均比单一的三聚氰胺或苯酚的效果好；通过进一步研究发现，增强荆用量在尿素总质量的5％时效果较好，增强剂的投料方式采用随第2次甲醛、第2次尿素同时加入为宜。