哈尔滨松花江斜拉大桥9#主塔承台施工

大体积砼浇筑、冬季施工、水中作业是桥梁施工的难点，通过哈尔滨松花江斜拉大桥9^#主塔承台实施实践，分析总结了这三个施工工艺，从而为指导桥梁施工提供了参考。     

慈姑茎尖组织培养与快速繁殖

以慈姑茎尖为外植体,用不同培养基进行组织培养,以所获得的试管苗为材料进行快速繁殖技术研究。结果表明,慈姑茎尖培养的最适启动培养基为MS+6-BA1.0mg·L~(-1)+NAA0.3mg·L~(-1);继代增殖的最适培养基为-S+6-BA3.0mg·L~(-1)+NAA0.1mg·L~(-1),增殖系数为4.35。     

The primary structure of wheat glutenin subunit 1Dx2 revealed by electrospray ionization mass spectrometry

The high molecular weight glutenin subunits (HMW-GS) play a key role in end-use quality of wheat. Their particular primary structure is mostly derived from DNA sequencing, which gives no information on potential post-translational modifications. This paper reveals the primary structure of HMW-GS 1Dx2 by proteomic analysis. For this purpose, HMW-GS were first isolated from wheat flour (cv. Contra). The relative molecular mass (M_r) of subunit 1Dx2 present in the HMW-GS mixture was then very accurately determined with high-performance liquid chromatography–electrospray ionization-mass spectrometry using a quadrupole-time-of-flight mass analyzer (HPLC–ESI-QTOF-MS). The obtained M_r value (87,105) differed from the value derived from its protein sequence in the NCBI database (87,007). The subunit was further purified by preparative reversed-phase HPLC and partially hydrolyzed with chymotrypsin. The resulting 1Dx2 peptides were then analyzed by HPLC–ESI-MS/MS and the MS data were compared to amino acid sequences in protein databases. The discrepancy between the calculated and the measured M_r of 1Dx2 was explained by a missing proline in the 1Dx2 amino acid sequence from the database and not by any post-translational glycosylation.     

水牛成熟前后卵泡液的多肽组鉴定和分析

卵泡液为雌性配子的成熟和发育提供生长微环境,在不同卵泡发育时期,卵泡液中的蛋白质成分会产生变化,这些变化与卵泡发育、排卵和卵母细胞成熟有直接关系。本研究对水牛卵泡液开展多肽组学分析,采用超滤方法富集内源性多肽,建立了稳定的多肽组制备方法。使用MALDI-TOF飞行时间质谱仪采集多肽信号,共采集到297个质谱峰,鉴定得到43个多肽或蛋白质前体,95%的多肽分子量在15kD以下。其中成熟卵泡液鉴定得到36种,未成熟卵泡液中鉴定得到24种,两者均能鉴定得到17种。经生物信息学分析,在鉴定得到的多肽中,共参与细胞因子受体相互作用、细胞周期和生长激素信号传导等7个调控代谢通路。本实验的多肽组学研究为卵泡发育机理提供了新的研究方法和参考数据。     

Variation in avenanthramide content in spring oat over multiple environments

Avenanthramides (AVNs), a group of phytochemicals which are unique to oats, provide health benefits through antioxidant activity and other bioactivities. In this study, we explored genotype-by-environment interactions and heritability for AVN concentrations in oats. Avenanthramide concentrations were quantified for 100 breeding lines and cultivars at three locations over two years. While year and environment had an influence on AVN concentrations, with the influence of year being more apparent than that of environment within a year, genotype had the largest impact on AVN concentration. All three major AVNs were found to be heritable. Two methods of calculating heritability on a line mean basis were used. The statistical method yielded heritability estimates of 0.34, 0.39, and 0.41 for AVN 2c, AVN 2p, and AVN 2f, respectively. By comparison the traditional plant breeding method yielded heritability estimates of 0.82, 0.88, and 0.89 for AVN 2c, AVN 2p, and AVN 2f, respectively, indicating that expected gains will be dependent on the scale of the breeding program, the number of target environments, and climate variability. The estimated heritabilities and the 11-fold range in AVN concentrations in the 100 genotypes studied provided evidence that variability for AVN concentration should allow breeding progress for higher AVN concentration.     

Ultra-fast separation of wheat glutenin subunits by reversed-phase HPLC using a superficially porous silica-based column

A relatively new, unique column packing material for reversed-phase high-performance liquid chromatography (RP-HPLC) was evaluated for rapid separation of wheat glutenin protein subunits. The product named “Poroshell” by the manufacturer consists of a solid core and a porous coat instead of solid silica spheres used in conventional RP-HPLC column packing. This architecture favours rapid mass transfer, facilitating faster reversed-phase separations of biomolecules compared to conventional silica columns. The main objective of this study was to evaluate the quality of separations of glutenin subunits (GS), as well as to optimize conditions to produce the fastest possible run times without sacrificing resolution using a Poroshell 300SB-C₈ 2.1×75 mm column. The stability of GS separations over time was also assessed. Two different bread wheat genotypes were used for optimization of separation conditions and six more common and durum wheat genotypes possessing different subunit combinations were used for further evaluation. Glutenin protein was extracted with 0.08 M Tris–HCl buffer (pH 7.5) containing 50% 1-propanol under reducing conditions after pre-extraction of soluble proteins with 50% 1-propanol. Optimization of GS resolution and sample throughput by RP-HPLC was assessed in response to variation in eluent flow rate, acetonitrile (ACN) gradient, and column temperature. The best resolution of both HMW- and LMW-GS was obtained in 13 min using a 23–44% ACN gradient with a flow rate of 0.7 mL/min at 65 °C. Subunit elution times and integrated areas were highly repeatable even after several hundred injections. Highly satisfactory separation of HMW-GS and quantification of ratio of HMW- to LMW-GS were achieved in less than 4 min per sample using a modified HPLC gradient. Ratio of HMW- to LMW-GS was unaffected by the speed of the separations. As well, the elution order of HMW- and LMW-GS was unaffected by the rapid analysis, compared to conventional RP-HPLC separations, so no new learning was required for interpreting chromatograms and classification of subunits. The rapid RP-HPLC method using the Poroshell column appears to be very well suited for routine quantification of HMW-GS and LMW-GS especially for purposes of wheat quality screening and wheat cultivar development activities where large numbers of samples are typically encountered.     

简易HPLC法测定甜菊叶中甜菊糖苷

一般甜菊叶中甜菊糖苷的HPLC检测样品处理复杂,采用简易超声波水提取法处理样品,建立快捷分析方法。甜菊糖苷在300~1500μg/mL内呈线性关系,相关系数为0.9998,平均加标回收率98.32%,相对标准偏差0.63%。该方法操作简单、重复性好、稳定性好、灵敏度高,可为甜菊叶中甜菊糖苷的测定提供参考。     

氯氰菊酯与p53-DNA相互作用的光谱研究

采用紫外、荧光分光光度法研究了农药氯氰菊酯与人类肿瘤抑制基因p53-DNA之间的相互作用.实验出现紫外减色、荧光猝灭等结果表明氯氰菊酯可能是以嵌插模式与p53-DNA结合作用;紫外变温实验得出p53-DNA熔点温度略有升高等结果则进一步证实氯氰菊酯是部分嵌插入DNA的沟区,影响了DNA的双螺旋结构的稳定性.     

试析晏式平民教育思想的历史意义及对现代农村教育的价值

晏阳初平民教育思想的目标与对象非常明确,教育内容与方式行之有效。在历史上平民教育思想丰富了乡村教育的内容,实现了教育对象的大众化,教育内容的实用化,教学方法的多样化;促进了教育者信仰的坚定与能力的提高;激发了受教育民众的思想与活力。晏式的平民教育思想对现代农村教育仍有积极的价值导向:现代代农村教育需要"平教专家"的指导,实现农业现代化;需要"四大教育"的推进,实现农民市民化;需要"三大方式"的连锁推进,实现农村城市化,从而更好促进城乡一体化的实现。     

Decomposition of a Native Shrub,Piliostigma reticulatum,Litter in Soils of Semiarid Senegal

Developing effective management strategies that restore degraded soils requires an evaluation of the quality of the litter residues. This study relates the chemical composition of the biomass components to the decomposition rates for Piliostigma reticulatum (DC.) Hochst., a native shrub, under field and laboratory conditions. The rates were determined by mass loss. The changes in the specific surface area of the residue in relation to mass loss ranged from 15 X 10 -5 to 45 X 10 -5 which was similar to crop residues in other studies. At field conditions, P. reticulatum mass loss was higher (80% of the initial mass lost over eight months) than that under controlled conditions (50%). Such fast decomposition of residues offers the potential for farmers to stop burning these residues because high amounts of residues will not likely accumulate and cause interference with tillage and planting operations. Further studies are needed on the role of soil fauna on decomposition, mineralization of nutrients from these residues, and the potential for incorporating residues into the system without burning.