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991.
应用热扩散法测定香蕉树蒸腾速率   总被引:2,自引:4,他引:2  
香蕉树植株高大,一般采用间接方法确定耗水量,但所得结果受土壤、大气和农艺措施等因素的影响较大.本文于2005年11月15日—12月5日在温室内采用热扩散法(即Granier法)测定香蕉树的茎液流,并与用数字天平(称重法)测定的香蕉树蒸腾速率进行对比试验. 结果表明,Granier法测定的日茎液流量与称重法测定的日蒸腾量相差4%.Granier法测定的茎液流速率一般滞后于称重法确定的蒸腾速率1 h左右.当日蒸腾量小于0.05 L·m-2(活性叶面积)时,Granier方法不能测定茎液流量.Granier传感器一般在安装2~3 d后即可正常工作,同时在多株植株上安装Granier传感器取其平均流速值计算蒸腾量可以明显减小测量误差.  相似文献   
992.
沼泽红假单胞菌中类胡萝卜素的提取与分析   总被引:1,自引:0,他引:1  
李福枝  刘飞  邓靖 《生物技术》2007,17(1):50-53
目的:研究沼泽红假单胞菌中类胡萝卜素的提取工艺条件。方法:对细胞收集、前处理、色素初浸、二次萃取,皂化和溶剂回收等方面进行了系统的研究,并通过紫外分光光度法和高效液相色谱法对所提取的类胡萝卜素进行了分析。结果:实验结果表明,类胡萝卜素的最佳提取工艺条件为:碱性氯化钙絮凝法收集细胞,乙醇浸泡法进行前处理,49℃下丙酮初浸提浸提4h(搅拌并加抗氧化剂),丙酮用量为5mL/g菌泥,回收丙酮,乙醚二次萃取,30℃下皂化1.5h,洗涤,浓缩并回收乙醚,在此提取工艺条件下不仅能够有效地提取红螺菌中的类胡萝卜素,而且还能分离细菌叶绿素。结论在本实验条件下,根据标准曲线计算出类胡萝卜素的含量高达6.148mg/L菌泥。通过HPLC分析表明:类胡萝卜素提取液中主要成分至少有10种。  相似文献   
993.
The intestinal parasites are noted to be an important health problem in Turkey as similarly reported in the globe. The aim of this study was to investigate the changes in total content of essential elements, namely, zinc, iron, copper, cobalt, magnesium, and selenium, in children infected with intestinal parasites aged between 6 and 12 years inhabiting in Hatay Province, Turkey. These essential elements were measured in the children/patient who was positive for intestinal parasites, Giardia intestinalis and Enterobius vermicularis. Scores were obtained from the positive study group (SG), and their age matched the healthy children control group (CG). Serological levels of zinc, iron, copper, cobalt, magnesium, and selenium were analyzed by Varian Liberty Series II inductively coupled plasma atomic emission spectrometer (ICP-AES). The mean magnesium concentrations were found to be statistically different at 95% confidence interval level between study groups. As a result of this study, selenium was found to be uncorrelated with all other elements examined; whereas, copper was observed to have statistically significant correlations with cobalt, magnesium, and zinc. In addition, cobalt-magnesium, cobalt-zinc, and magnesium-zinc metal pairs were found to have statistically significant correlations based on study findings.  相似文献   
994.
裴泉清  张胜林 《蛇志》1996,8(4):26-27
应用清栓酶治疗不同病期脑梗塞38例,总有效率86.7%,发病后治疗时间越早,疗效越好。治疗前病人均有不同程度的TXA2升高,PGI2下降,急性期更为明显,治疗后TXA2下降,PGI2上升,使失调的PGI2-TXA2平衡得以恢复  相似文献   
995.
Extracellular vesicles, which are highly conserved in most cells, contain biologically active substances. The vesicles and substances interact with cells and impact physiological mechanisms. The skin is the most external organ and is in direct contact with the external environment. Photoaging and skin damage are caused by extrinsic factors. The formation of wrinkles is a major indicator of skin aging and is caused by a decrease in collagen and hyaluronic acid. MMP-1 expression is also increased. Due to accruing damage, skin aging reduces the ability of the skin barrier, thereby lowering the skin’s ability to contain water and increasing the amount of water loss. L. plantarum suppresses various harmful bacteria by secreting an antimicrobial substance. L. plantarum is also found in the skin, and research on the interactions between the bacteria and the skin is in progress. Although several studies have investigated L. plantarum, there are only a limited number of studies on extracellular vesicles (EV) derived from L. plantarum, especially in relation to skin aging. Herein, we isolated EVs that were secreted from L. plantarum of women in their 20s (LpEVs). We then investigated the effect of LpEVs on skin aging in CCD986sk. We showed that LpEVs modulated the mRNA expression of ECM related genes in vitro. Furthermore, LpEVs suppressed wrinkle formation and pigmentation in clinical trials. These results demonstrated that LpEVs have a great effect on skin aging by regulating ECM related genes. In addition, our study offers important evidence on the depigmentation effect of LpEVs.  相似文献   
996.
目的 观察大鼠诱发肝癌过程中Sonic Hedgehog(Shh)信号通路相关基因的表达变化,探讨其在肝癌发生发展过程中的作用.方法 雄性Wistar大鼠48只,随机分成4组,利用二乙基亚硝胺(DEN)制备诱发性大鼠肝癌模型,应用原位核酸杂交技术检测Shh、Ptc、Gli1 mRNA在对照组、模型组(6w)、模型组(14w)、模型组(22w)大鼠肝脏癌变过程中的表达变化.结果 在模型组(6w)大鼠肝脏的肝小叶周边可见嗜酸性、气球样变性等肝细胞损伤的表现,模型组(14w)大鼠肝脏中可见肝假小叶和非典型增生结节,模型组(22w)大鼠肝脏中可见到高分化的肝细胞癌结节.Shh、Ptc、Gli1 mRNA阳性表达细胞主要分布在大鼠肝脏中的肝细胞损伤区、增生结节、癌结节、小叶间胆管上皮和癌旁组织中,Shh、Ptc、Gli1 mRNA在模型组的大鼠肝组织中表达的平均光密度值均高于对照组.结论 Shh信号通路在诱癌过程中异常激活,可能促进肝损伤后的正常修复、异常增殖及肝细胞癌变过程.  相似文献   
997.
998.
Two full-length hexokinase (HXK, EC 2.7.1.1) cDNAs, VvHXK1 with 1,413 bp and VvHXK2 with 1,458 bp were cloned from grape berries (Vitis vinifera L. Cabernet Sauvignon). VvHXK1 and VvHXK2 genes sequence from grape berries were deposited in GenBank under the accession number JN118544 and JN118545, respectively. The homology of the amino acid of VvHXK1 or VvHXK2 was very similar to ‘Pinot Noir’ grape HXK sequence, their similarties were 99.36 % and 98.97 %, respectively. More intuitive phylogenetic tree showed that the homology of amino acid sequence VvHXK1 with melon CmHXK1 was 86 %, and VvHXK2 homology with rice OsHXK3 was 83 %. The HXK proteins were successfully expressed in plasmid pET-30a (+) vectors in Escherichia coli BL21 (DE3) pLysS. The expressed proteins were purified using Ni-NTA agarose column and used to produce HXK1 antibody and conducted HXK protein blotting analysis. The results,suggested that one polypeptide band of about 51 kDa HXK protein can be detected in grape berries, HXK protein level was the highest during early grape berry development, but the lowest from 50d to 60d during development. Biochemical analysis of two hexokinase isozymes indicated that glucose was the optimal substrate of HXK, The isoelectric points of the two isozymes were 5.8 and 5.6, respectively. And the optimum pH was about 8.0. These results provide a substantial basis for the further studies of functions of grape HXKs to manipulate sugar content of grape berries.  相似文献   
999.
婚飞行为影响中华蜜蜂性成熟处女蜂王的基因表达   总被引:1,自引:0,他引:1  
婚飞是性成熟处女蜂王与雄蜂交配过程中的一个重要前奏, 在该过程中蜂王体内伴随着一系列重要的生理变化。为了探究中华蜜蜂Apis cerana cerana处女蜂王婚飞过程中基因表达变化, 本研究利用数字基因表达谱(digital gene expression, DGE) 技术分析了中华蜜蜂性成熟处女蜂王飞行与未飞行之间的基因表达差异。经DGE测序, 分别从两个样品中获得5.98和6.01 百万条Clean标签。通过分析检测到250个基因有差异表达, 其中133个基因在飞行蜂王中上调表达, 117个基因在飞行蜂王中下调表达。这些差异基因可以归类到348个功能性类别和142个生化途径。结果表明中华蜜蜂性成熟处女蜂王在婚飞过程中大量基因的表达发生了变化。这些结果为进一步研究中华蜜蜂蜂王婚飞过程中生理变化的分子机制提供了重要的基因表达信息。  相似文献   
1000.
The employment of biochar in crop production can not only improve soil quality, but also helps the field ecosystem to fix carbon and reduce emissions. Although the benefits of their application in crop production have been more and more confirmed, it is not clear when it comes to the acidic soil of tobacco and rice rotation. A tobacco–rice rotation experiment was conducted in southern China to probe the application value of biochar under these conditions. Three biochar application rates were employed in this experiment. BC0 (without biochar), BC25 (25 t ha−1), and BC50 (50 t ha−1). The findings show that biochar significantly boosted soil fertility and crop yields. Meanwhile, the soil organic carbon of tobacco rice rotation field with biochar increased by 31.76%. After a whole growth period of tobacco and rice, the cumulative emission reduction of CO2 and N2O from the soil by biochar were 15,944 kg ha−1 and 1810 g ha−1, respectively. The use of biochar not only significantly improved the bacterial diversity of tobacco and rice rotation soil, but also altered the original microbial community structure. The profusion of Proteobacteria and Acidobacteria was reduced and the abundance of Actinobacteria and Bacteroidetes was enhanced in the treatments with biochar. Among them, Sphingomonadales, Planctomycotes, and Ktedonobacteria, which are beneficial to plant growth and soil health, have become key phylotypes. The carbon balance analysis data show that the net carbon sequestration of the two treatments with biochar is positive, while that of the treatment without biochar is negative. In terms of economic benefit, the application of biochar increased the average of 2.055 CNY kg−1 consumed energy (CE) in the whole tobacco–rice rotation system. The ecological benefit was 0.51 kg C kg−1 CE. In conclusion, biochar can be effectively used in the practice of tobacco–rice rotation and acidic soil improvement in southern China.  相似文献   
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