耐辐射异常球菌高温胁迫下双组份系统 dtrAB基因的功能分析

分析预测了耐辐射异常球菌(Deinococcus radiodurans)基因组中的一对双组份蛋白DtrA（DR_A0009）和DtrB（DR_A0010）。生物学软件分析结果显示,DtrA含有组氨酸激酶（HisKA_3）结构域和ATP酶（HATPase_c）结构域,且有4个跨膜区;DtrB含有接收结构域和HTH结构域,且有Lux家族的调控蛋白。两者共同构成一个转录单元。分别构建了dtrA和dtrB基因缺失突变株（ΔdtrA和ΔdtrB）,发现42℃高温胁迫条件下,2个突变株的生长和生存率明显低于野生型菌株,而正常培养温度（30°C）条件下,突变株和野生型菌株的生长无差异。QRT\|PCR分析显示,dtrA或dtrB基因突变导致了热激相关基因发生下调。推测双组份蛋白DtrAB参与了耐辐射异常球菌在高温胁迫下的调控作用。     

Effects of enhancing vitamin D status by 25-hydroxycholecalciferol supplementation,alone or in combination with calcium and phosphorus,on sternum mineralisation and breast meat quality in broilers

1. The aim of the present study was to examine the effects of improving vitamin D status in broiler diets by supplementary 25-hydroxycholecalciferol (25OHD₃), alone or in combination with calcium (Ca) and available phosphorus (aP), on live performance, sternum mineralisation and breast meat quality in broilers.

2. A total of 936 1-d-old Ross 308 broilers were used in the study. After gender determination at the hatchery, chicks from each sex were randomly distributed into three dietary treatments. The following dietary treatments were used in the experiment from hatch to 38 d: (1) A control diet formulated to meet all of the nutrient requirements of broiler chicks according to the management guide; (2) The control diet supplemented with 18.7–15.0 µg/kg of 25OHD₃; and (3) The control diet supplemented with 18.7–15.0 µg/kg of 25OHD₃ plus Ca + aP.

3. Improvement in vitamin D status by 25OHD₃ supplementation, alone or in combination with Ca and aP, had no effect on body weight and feed conversion ratio of broilers.

4. The serum 25OHD₃ concentration significantly increased with 25OHD₃ and 25OHD₃ plus Ca + aP supplementation (P < 0.05), whereas the ionised Ca and Mg concentrations remained unchanged.

5. Sternum absolute weight, ash content and the concentrations of Ca and P significantly increased (P < 0.01) with supplementation of 25OHD₃, alone or in combination with Ca + aP.

6. Supplemental 25OHD₃, alone or in combination with Ca + aP, slightly increased pH₂₄ (P = 0.05) and decreased (P < 0.01) squeezable water loss in breast meat, whereas it had no significant effect on lightness, yellowness and sarcoplasmic protein solubility.

7. In conclusion, the results suggested that enhancing vitamin D status by 25OHD₃ supplementation alone or in combination with Ca + aP may improve sternum structure and mineral accretion. Furthermore, supplemental 25OHD₃, even in a nutritionally complete diet, may offer an effective way to improve protein solubility in female broilers.     

Root development of Thuja plicata in peat-substitute rooting media

In this study we investigated the potential usefulness of different substrates produced from gorse (Ulex europaeus L.) for propagating cuttings of Thuja plicata ‘Atrovirens’. The gorse was composted by different methods, to produce four types of compost. These composts were then used as such (100% compost) or in mixes with coarse sand and pine bark compost (25% compost, 25% coarse sand and 50% pine bark compost, v/v/v) to prepare eight different substrates. The substrates were compared in cutting propagation trials carried out in a greenhouse, with a standard rooting medium consisting of 25% Sphagnum peat moss, 25% coarse sand and 50% pine bark compost (v/v/v). Cuttings were taken from a garden hedge in March 2003, and comprised shoots of the previous year's growth. The bases of the cuttings were treated with a 0.4% solution of IBA rooting hormone, then inserted into cells filled with the corresponding substrate and placed on a propagation bench. Rooting percentage and visual rooting score were determined in July. The quality of roots was evaluated, as total root length and number of root tips, in July, September and November 2003, by use of a Delta-T Scan system. The rooting success of the cuttings ranged from 75% to 90%, except when the substrate comprised the pure composted gorse, obtained after the shorter period in an enclosed composting system with addition of fertilizer and reuse of leachates. Most of the cuttings in this substrate died and only 4% of the cuttings rooted successfully. Physicochemical characteristics of this rooting medium included very high electrical conductivity, low C/N ratio and high water retention. Addition of coarse sand and pine bark compost to the composted gorse significantly increased the rooting success. The root quality variables differed depending on the substrate considered and date of harvest. The results showed that substrates made from gorse compost are of potential use as a peat substitute for propagating cuttings of T. plicata ‘Atrovirens’. The physicochemical properties of the composted gorse should be determined before its use to establish whether it can be used pure as a substrate for rooting or whether it should be mixed with other substances.     

Influence of hydrothermal treatment on rheological and cooking characteristics of fresh egg pasta

The effect of D.I.C. processing conditions on rheological and cooking properties of commercial fresh egg pasta was studied. The mechanical properties of pasta before and after cooking were evaluated by empirical test and characterised by maximal apparent force (F_max) and apparent relaxation coefficient (ARC). Structural (apparent density) and cooking quality were evaluated by determining mass ratio (W/Wo), optimal cooking time (OCT), swelling index (SI), solid, soluble and total cooking losses (TCL) and compared to untreated pasta. The hydrothermal treatment caused a reduction in firmness and relaxation capacity of treated pasta. The increase of processing conditions induced a decrease of F_max and the processing time has an influence when it is associated to the low pressures. The values of ARC vary from 51% (untreated pasta) to 37% (D.I.C. treated pasta). The increase of processing time from 30 to 60 s does not seem to have a significant influence on ARC. The apparent density of treated pasta is a function of processing pressure and time but it is always lower than untreated pasta density. Treated pasta had a higher quality score based on water sorption and SI and matter losses (TCL values and solid and soluble losses) as compared to untreated pasta.     

三维波钢混凝土壳体的理论分析与数值计算

混凝土壳体结构具有广阔的应用前景,为探索该结构应用的理论基础,本文基于所有的肋条,钢板,钢筋的抗拉抗弯效果均匀分布,利用经典壳体理论,推导出内衬三维波纹钢板钢筋混凝土壳体的基本微分平衡方程组。用三角级数法对该结构进行处理,并与对照组相比较,结果发现,三维波纹钢混凝土壳体能够抵抗变形。     

高寒地区禾草混播草地杂草防除研究

研究高寒地区多年生禾草混播草地建植当年的杂草种类、危害程度及所用除草剂的最佳和最大剂量。结果表明,混播草地杂草有10种,均为阔叶型,杂草草情指数高(74.08),危害严重。采用高效低毒、具有较强选择性和内吸传导性的2,4-D丁酯进行防除,其最佳剂量(按有效成分)为1188g/hm²;最大剂量为1622g/hm²。     

人力资本对河南省食品产业增长贡献度的研究

基于人力资本视角,利用EVIEWS软件,通过对1998～2011年河南省食品产业统计数据进行分析,探究当前食品产业经济增长的主要驱动力是依靠物质资本的投入还是依靠人力资本的投入。结果表明：人力资本投入对河南省食品产业经济增长的贡献率远远低于物质资本投入,当前经济增长的主要驱动力是物质资本投入,人力资本尤其是R＆D人员的贡献还很低。并主要针对河南省食品产业发展进程中提升科技人才对经济增长的贡献提出了若干建议。     

3D打印技术在食品工业中的应用概述

3D打印具有灵活、便捷、个性化的特点,在食品工业中得到较快发展,简述3D打印技术的原理,概述几种食品3D打印技术,并对可打印材料的特点进行分析,重点阐述了目前3D打印技术在食品领域中的应用,以期为食品3D打印技术的发展提供参考。