Interactions between the carbohydrate chains of hyaluronate and chondroitin sulphate

Hyaluronic acid-derivatised beads spontaneously agglutinate with chondroitin-sulphate-derivatised beads although neither bead type shows any self-agglutination. The interaction between hyaluronate and chondroitin sulphate is specific for these two glycosaminoglycans and appears to occur between their carbohydrate chains.     

Drainage and nitrogen loss in dry soils with controlled drainage

为探讨不同暗管控制水位对旱地排水、氮素流失过程和流失总量流失的影响,选取控制水位为地下Ocm,30cm,50cm,80cm,1OOcm的5块暗管排水棉花地进行对照试验,测定2a棉花生育期内发生的4次较大规模排水过程的排水量、排水中氮素含量.结果表明,暗管排水条件下,暗管排水量高于地表径流排水量,且明显随控制水位的增加而降低,总排水量随暗管控制水位降低而有增加的趋势;各田块暗管排水中硝氮和全氮质量浓度变化规律明显,初始时较小,逐渐增大到峰值后又逐渐减少;暗管铵氮排放量与排水量明显呈线性相关;暗管径流氮素流失量总体上随暗管控制水位升高而减少.因此,适当提高暗管控制水位能减少旱地排水量和氮素流失量.     

鸡冠中透明质酸提取工艺条件的研究

以新鲜公鸡冠为原料对透明质酸的提取方法进行研究.以透明质酸得率为指标,确定采用乙醇处理为最佳方法,选择乙醇体积分数、料液比、提取时间为影响因素,通过单因素和正交试验确定了透明质酸的最佳提取条件:透明质酸提取液与乙醇体积比为1∶2;乙醇体积分数为85％;提取时间为26 h,得到该工艺条件下制备的透明质酸得率为4.84％.通过紫外光谱法检测,显示该提取物质与标准品峰形位置一致,确定该提取物质是透明质酸.     

发酵法生产透明质酸菌种的选育

用物理方法紫外线、γ射线及辅助磁场筛选、诱变兽疫链球菌,研究获得性状优良、产量相对稳定的透明质酸高产菌种,透明质酸产量可稳定在３～５ｇ／Ｌ。     

饥饿状态下凡纳滨对虾生化组成与能值的关系

于2003年7-9月对初始体质量分别为(4．77±0．52)g(S组)、(8．56±0．56)g(M组)、 (11．43±0．89)g(L组)的凡纳滨对虾进行了饥饿实验．结果表明,对虾肌肉中的干物质、蛋白质、脂 肪等的质量分数和能值的变化均与饥饿时间呈显著的负相关关系(P<0．01),而干物质、蛋白质和 脂肪等的质量分数的变化与能值呈显著的正相关关系(P<0．01);饥饿过程中,干物质、脂肪、碳水 化合物等的质量分数和能值的减少速率随着体质量的增大而增加,而蛋白质质量分数的减少速率 随体质量的增大而减少．分析认为,蛋白质是影响饥饿期间凡纳滨对虾肌肉能值变化的重要的含 能物质．     

饥饿状态下南方鲇仔鱼的形态和行为变化

饥饿状态下的南方鲇仔鱼外形萎缩,脑顶下凹,外部器官发育受阻,身体长度和对照组存在显著差异．饥饿仔鱼的行为反应可分４个阶段：①集群趋暗阶段;②游动觅食阶段;③狂游阶段;④散慢游动阶段．对１８℃,２０℃,２４℃和２８℃４个温度组的观察结果表明,饥饿仔鱼的反应特征基本一致,温度越高,每一阶段持续时间越短．饥饿仔鱼具同类相残和吞食气泡的习性,同类相残行为与温度成正相关,胃肠吞有气泡的仔鱼数在中间温度组（２０℃,２４℃）较多,高温组（２８℃）和低温组（１８℃）均较少．     

南方鲇幼鱼胃和肝脏的组织结构及其在饥饿过程中的变化

描述了南方鲇（Ｓｉｌｕｒｕｓｍｅｒｉｄｉｏｎａｌｉｓ）幼鱼的胃和肝脏的基本形态和组织结构及其在饥饿过程中的变化．发现随饥饿时间延长,胃粘膜皱褶高度、粘膜下层厚度、上皮细胞高度及胃腺厚度均有明显减少趋势．肌肉层厚度呈先降后升再下降的趋势．饥饿过程中还发现各层组织,特别是肌肉层有结缔组织增生和崩溃疏松的现象．饥饿鱼肝脏的肝细胞体积明显减小,细胞索紊乱,细胞间隙增大．胃的上皮细胞高度和胃腺厚度可作为南方鲇幼鱼营养状况的指标     

TNF-mediated inflammatory skin disease in mice with epidermis-specific deletion of IKK2

The I kappa B kinase (IKK), consisting of the IKK1 and IKK2 catalytic subunits and the NEMO (also known as IKK gamma) regulatory subunit, phosphorylates I kappa B proteins, targeting them for degradation and thus inducing activation of NF-kappa B (reviewed in refs 1, 2). IKK2 and NEMO are necessary for NF-kappa B activation through pro-inflammatory signals. IKK1 seems to be dispensable for this function but controls epidermal differentiation independently of NF-kappa B. Previous studies suggested that NF-kappa B has a function in the growth regulation of epidermal keratinocytes. Mice lacking RelB or I kappa B alpha, as well as both mice and humans with heterozygous NEMO mutations, develop skin lesions. However, the function of NF-kappa B in the epidermis remains unclear. Here we used Cre/loxP-mediated gene targeting to investigate the function of IKK2 specifically in epidermal keratinocytes. IKK2 deficiency inhibits NF-kappa B activation, but does not lead to cell-autonomous hyperproliferation or impaired differentiation of keratinocytes. Mice with epidermis-specific deletion of IKK2 develop a severe inflammatory skin disease, which is caused by a tumour necrosis factor-mediated, alpha beta T-cell-independent inflammatory response that develops in the skin shortly after birth. Our results suggest that the critical function of IKK2-mediated NF-kappa B activity in epidermal keratinocytes is to regulate mechanisms that maintain the immune homeostasis of the skin.     

Occurrence of nitrification-denitrification and gaseous nitrogen loss process in flooded rice soil

Flooding in wetland rice fields soon after transplanting results in displacement of soil air (including O₂). Thus any dissolved O₂ in the pore water is consumed out by microbial respiration in a short period. Supply of O₂ to the flooded rice soil is by diffusion of O₂ through the standing floodwater and consumption at the soil-water interface, and by exudation of O₂ by rice roots and subsequent diffusion of O₂ into the rhizosphere. The greater potential consumption of O₂ compared to the renewal rate results in the development of distinct soil layers: oxidized soil layers under soil-water interface and in the rhizosphere, and reduced soil layers or reduced bulk soil. Nitrification in oxidized soils and denitrification in reduced soils have been known. Currently, denitrification in oxidized soils, even in standing floodwater, has also been identified. In this article, we present a modified nitrification and denitrification occurring mechanism in flooded rice soil.     

Occurrence of nitrification-denitrification and gaseous nitrogen loss process in flooded rice soil

Flooding in wetland rice fields soon after transplanting results in displacement of soil air (including O2). Thus any dissolved O2 in the pore water is consumed out by microbial respiration in a short period. Supply of O2 to the flooded rice soil is by diffusion of O2 through the standing floodwater and consumption at the soil-water interface, and by exudation of O2 by rice roots and subsequent diffusion of O2 into the rhizosphere. The greater potential consumption of O2 compared to the renewal rate results in the development of distinct soil layers: oxidized soil layers under soil-water interface and in the rhizosphere, and reduced soil layers or reduced bulk soil. Nitrification in oxidized soils and denitrification in reduced soils have been known. Currently, denitrification in oxidized soils, even in standing floodwater, has also been identified. In this article, we present a modified nitrification and denitrification occurring mechanism in flooded rice soil.     

气隙式膜蒸馏法分离浓缩透明质酸水溶液的研究

介绍了应用气隙式膜蒸馏分离技术对透明质酸热敏性水溶液的浓缩分离情况。结果表明，使用膜孔径为０．２μｍ的聚四氟乙烯微孔疏水可使原料液的浓度提高１．６倍以上，透明质酸截留率为８０％以上，探讨了循环时间、平均温差，热侧温度等条件对分离效果的影响，并讨论了膜蒸馏过程热效率的变化规律。     

土壤含水量与氮化合物迁移转化的相关性分析

在蒸渗仪内进行的灌溉实验结果表明，土壤含水量的变化是影响溶液中有机质和氮化合物迁移转化的主要因素。降雨和灌溉以后，随土壤含水量的上升，微车物活性增强，有机物分解和成氨作用速度加快，COD和NH4^ -N浓度随之增加。NH4^ -N离子浓度的提高加速硝化作用的进行，但土壤含水量的增加也同时加速了N03^—离子的淋溶和反硝化作用，因此，土壤含水量与N0^3— -N浓度之间没有很好的相关性。