粘质沙雷氏菌XJ-01几丁质酶合成条件的优化

目的:对粘质沙雷氏菌(Serratia marcescens)XJ-01几丁质酶合成条件优化.方法:研究了碳源、氮源、温度、pH等单个因素对该菌几丁质酶合成的影响,并通过正交实验确定了该菌的最适酶合成条件.结果:该茵几丁质酶最优合成条件为:胶体几丁质5g/L、硫酸铵5 g/L、培养温度32℃、最适pH 8.结论:优化了S.marcescens XJ-01几丁质酶的合成条件.     

Seasonal change and habitat selection of shorebird community at the South Yangtze River Mouth and North Hangzhou Bay, China

Coastal regions are important habitats for migratory shorebirds. The aim of the study is to understand habitat use by migratory shorebirds and to develop a conservation strategy in the sustainable use of wetlands. From March 2004 to January 2005, we conducted a seasonal shorebirds census in ten coastal habitats along the South Yangtze River mouth and North Hangzhou Bay, simultaneously examining the relative seasonal abundance of shorebirds and their spatial distribution. A total of 25 species were identified, the dominant seasonal species were Great Knot (Calidris tenuirostris), Sharp-tailed Sandpiper (Calidris alpine) and Red-necked Stint (Calidris ruficollis) in spring; Kentish Plover (Charadrius alexandrinus), Common Greenshank(Tringa nebularia) and Lesser Sand Plover (Charadrius mongolus) in summer; Kentish Plover, Red-necked Stint and Common Greenshank in autumn; Dunlin(Calidris alpine), Kentish Plover and Marsh Sandpiper (Tringa stagnatilis) in winter. These species accounted for more than 85% of the total shorebirds. The numbers of shorebirds counted was highest in spring and then in autumn, winter and summer respectively. Among the four seasons, there were few significant differences in the number of bird species between the sites outside the seawall (intertidal mudflat) and the sites inside the seawall (artificial wetland), but the average density of shorebirds was obviously different. The habitat-selection analysis of the environmental factors (outside and inside the seawall) impacting on the shorebird community was made in the 10 study sites with Canonical Correspondence Analysis. The study results indicated that: (1) Outside the seawall, the widths of the total intertidal mudflat and bare mudflat were the key factors affecting the shorebirds; the proportion of bulrush (Scirpus×mariquete) covering and supertidal mudflat width had a positive correlation with the abundance of birds, while human disturbance and the proportion of both reed (Phragmites communis) and smooth cord-grass (Spartina alterniflora) covering in total surveyed areas had negative impacts on bird numbers; (2) Inside the seawall, the proportions of areas with shallow water and mudflats occupying the total surveyed area were key factors influencing the number of birds; the size of the bulrush area should have a positive impact on the appearance of shorebirds. Habitats with heavy human disturbance, dense reed and smooth cord-grass or a high water level were not conducive to be inhabited by shorebirds.     

CD4+CD25+调节性T细胞作用机制的双模式

CD4 CD25 调节性T细胞是具有免疫抑制功能的细胞群,在多种生理病理过程中发挥了重要作用。它们的作用机制主要包括细胞-细胞接触依赖和可溶性细胞因子介导两种抑制模式。由于CD4 CD25 调节性T细胞的抑制机制复杂,争议较大,进一步阐明它们的作用机制将有利于多种免疫相关疾病的防治。     

青海湖裸鲤生长特征的研究

对2002年5月—2003年7月采自青海湖的1174尾青海湖裸鲤样本年龄进行了耳石鉴定,并依据年龄推算了生长率。青海湖裸鲤体长与体重的关系为:W=0.000174×L2.4990(♀)、W=0.0000402×L2.7538(♂),雌、雄个体生长差异显著。其体长Von Bertalanffy生长方程为:Lt=551.9301(1-e-0.0711(t 0.3044))(♀),Lt=682.8688(1-e-0.0530(t 0.4240))(♂);体重Von Bertalanffy生长方程为:Wt=1237.3431(1-e-0.0711(t 0.3044))2.4990(♀),Wt=2567.3242×(1-e-0.0530(t 0.4240))2.7538(♂)。其雌、雄生长拐点分别为12.57龄和18.67龄。     

人工接种发酵茯砖茶降脂减肥作用研究

比较自然发酵与人工接种发酵茯砖茶对营养性肥胖大鼠的降脂减肥作用。结果表明与肥胖模型组比较,喂饲两类茯砖茶的大鼠体重、脂肪湿重、脂肪系数、甘油三酯（TG）、总胆固醇（TC）等指标均低于肥胖模型组,而高密度脂蛋白（HDL-C）则有明显提高。人工接种发酵茯砖茶与自然发酵茯砖茶均对营养性肥胖大鼠有降脂减肥作用,能显著改善大鼠的各项肥胖指标,人工接种发酵的茯砖茶在相关指标上均接近甚至优于自然发酵的茯砖茶。     

松油烯-4-醇光学异构体及外消旋体对家蝇的杀虫活性比较

【目的】比较松油烯-4-醇光学异构体对家蝇 Musca domestica 的熏蒸活性差异,为其光学异构体的应用提供理论依据。【方法】以家蝇4日龄成虫为供试昆虫,采用三角瓶熏蒸法比较测定了松油烯-4-醇光学异构体和外消旋体对其的熏蒸与击倒活性,并测定了松油烯-4-醇光学异构体及外消旋体对家蝇头部Na⁺ , K⁺-ATPase活性的影响。【结果】松油烯-4-醇外消旋体对家蝇的熏蒸活性和击倒活性最强,右旋异构体次之,左旋异构体最差,外消旋体、右旋异构体和左旋异构体对家蝇的致死中浓度（LC₅₀）分别为2.5,2.9和3.7 μL/L;在LC₉₀ 剂量下的击倒中时（KT₅₀）分别为12.6,16.7和18.9 min;松油烯-4-醇光学异构体及外消旋体均可显著抑制Na⁺, K⁺-ATPase的活性,活体条件下,松油烯-4-醇光学异构体及外消旋体对Na⁺, K⁺-ATPase活性的抑制作用随着中毒症状的加剧而增强,具有时间效应,其中左旋异构体的抑制作用最强;离体条件下,松油烯-4-醇光学异构体及外消旋体对Na⁺, K⁺-ATPase活性的抑制作用具有浓度依赖效应,其中外消旋体对Na⁺, K⁺-ATPase活性的抑制能力最强,明显高于同浓度下的右旋异构体和左旋异构体。【结论】松油烯-4-醇的光学异构体对家蝇的杀虫活性存在差异,外消旋体的活性明显高于异构体单体。开发松油烯-4-醇类杀虫剂,应以光学异构体的混合物作为有效成分。     

葡萄糖、维生素C对普安银鲫卵黄囊仔鱼发育中LPL和HL活性的影响

通过设置不同浓度的葡萄糖溶液和维生素C溶液分别添加到普安银鲫的孵化水体中, 直至卵黄囊消失完全, 探究葡萄糖和维生素C溶液分别浸泡对普安银鲫(Carassius auratus gibelio)卵黄囊仔鱼发育中脂蛋白脂酶(LPL)和肝脂酶(HL)活性的影响. 葡萄糖浓度为0、5、10、15和20 g/L; 维生素C浓度为0、20、25、30和35 mg/L, 记录孵化时间、孵化率及仔鱼成活率, 并测定了最适葡萄糖浓度组、维生素C浓度组与对照组中普安银鲫卵黄囊仔鱼发育中LPL和HL活性. 结果显示: 普安银鲫卵黄囊仔鱼发育中对照组与维生素C组LPL比活力与全活力呈下降-上升的变化趋势, HL比活力与全活力均呈上升趋势. 葡萄糖组LPL和HL比活力与全活力呈上升趋势, 在混合营养期与外源营养期, LPL和HL比活力与全活力显著高于对照组(P0.05), 而维生素C组LPL和HL比活力与全活力仅稍高于对照组, 但HL全活力在内源营养期显著高于对照组(P0.05). 研究表明: 适宜水平的葡萄糖溶液可通过调节脂类代谢酶的活性来维持机体内脂质代谢的动态平衡, 同时适宜水平的维生素C溶液能促进脂质代谢.       

Response of vegetation phenology to urbanization in the conterminous United States

The influence of urbanization on vegetation phenology is gaining considerable attention due to its implications for human health, cycling of carbon and other nutrients in Earth system. In this study, we examined the relationship between change in vegetation phenology and urban size, an indicator of urbanization, for the conterminous United States. We studied more than 4500 urban clusters of varying size to determine the impact of urbanization on plant phenology, with the aids of remotely sensed observations since 2003–2012. We found that phenology cycle (changes in vegetation greenness) in urban areas starts earlier (start of season, SOS) and ends later (end of season, EOS), resulting in a longer growing season length (GSL), when compared to the respective surrounding urban areas. The average difference of GSL between urban and rural areas over all vegetation types, considered in this study, is about 9 days. Also, the extended GSL in urban area is consistent among different climate zones in the United States, whereas their magnitudes are varying across regions. We found that a tenfold increase in urban size could result in an earlier SOS of about 1.3 days and a later EOS of around 2.4 days. As a result, the GSL could be extended by approximately 3.6 days with a range of 1.6–6.5 days for 25th ~ 75th quantiles, with a median value of about 2.1 days. For different vegetation types, the phenology response to urbanization, as defined by GSL, ranges from 1 to 4 days. The quantitative relationship between phenology and urbanization is of great use for developing improved models of vegetation phenology dynamics under future urbanization, and for developing change indicators to assess the impacts of urbanization on vegetation phenology.     

食品微生物本科毕业论文实验的探索与实践——以干酪乳杆菌异源表达胆盐水解酶为例

毕业论文是本科教育教学过程中不可替代的重要环节之一,是检验学生综合素质的重要手段。以干酪乳杆菌异源表达胆盐水解酶为例,从论文选题、实验准备、实验研究和论文撰写等方面介绍上海理工大学食品微生物本科毕业论文实验的有关探索。学生通过综合运用所学理论知识和实验技能,能够顺利完成毕业论文实验,构建出具有工业应用潜力的耐胆盐干酪乳杆菌基因工程菌,达到本科毕业论文实践教学的目的。