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稻田土壤呼吸及酶活性对不同秸秆还田方式的响应
No full text为了解秸秆还田通过改变土壤酶活性影响稻田土壤二氧化碳排放的过程,通过大田试验分析小麦和油菜秸秆翻埋还田(W1,R1)、覆盖还田(W2,R2)以及不还田(CK)处理下土壤呼吸和酶活性的变化及其对不同秸秆还田方式的响应.结果表明:(1)不同秸秆还田方式下土壤呼吸均表现为双峰值,峰值分别出现在6月(208.3±6.1 mL/kg)和9月(106.2±13.5 mL/kg).除油菜秸秆翻埋还田外,其他秸秆还田方式均增加了土壤呼吸作用.(2)土壤脲酶和蔗糖酶对不同秸秆还田方式响应各异.不同秸秆还田方式下土壤脲酶活性变化较小,没有表现出显著差异性.由此表明,不同秸秆还田对氮相关酶活性及氮素转化影响较小.而蔗糖酶在不同秸秆还田方式下差异较大.(3)蔗糖酶与土壤呼吸存在显著正相关关系(P<0.05).上述结果表明蔗糖酶对秸秆还田较为敏感,可较好地表征秸秆还田过程中土壤呼吸变化状况,可为稻田营养循环利用提供有效依据
Cucurbitane glycosides from the fruit of Siraitia grosvenori and their effects on glucose uptake in human HepG2 cells in vitro
No full textThe mogrosides in the fruit of Siraitia grosvenori can serve as a sugar substitute for diabetics due to their sweetness, low calorie and positive effects on blood glucose level control. The present study was to purify the mogrosides from the fruit of S. grosvenori and evaluate their enhancement of glucose uptake rate in HepG2 cells in vitro. As a result, eighteen mogrosides were isolated, including six new ones and a known but new naturally occurring compound. The chemical structures of the new compounds were identified by 1D, 2D-NMR and HR-ESI-MS techniques, together with chemical methods. Compared to the positive control (metformin), all the obtained mogrosides showed equivalent or more potent effects on the glucose uptake in HepG2 cells in vitro. These results suggested the mogrosides in the fruit of S. grosvenori were worthy of further research to confirm their potential benefits for obese and diabetic patients. (C) 2017 Elsevier Ltd. All rights reserved
Copper-catalyzed direct hydroxyphosphorylation of electron-deficient alkenes with H-phosphine oxides and dioxygen
No full textA copper-catalyzed direct hydroxyphosphorylation of electron-deficient alkenes with H-phosphine oxides and dioxygen is reported. The present reaction, proceeds under mild reaction conditions with good functional group tolerance, affording the facile and efficient synthesis of various beta-hydroxyphosphine oxides in a scaled-up manner with moderate to good yields. (C) 2017 Elsevier Ltd. All rights reserved
Determination of Contents of Catechins in Oolong Teas by Quantitative Analysis of Multi-components Via a Single Marker (QAMS) Method
No full textThe catechins in oolong tea are related to its flavor and health benefits. In this paper, a new strategy for a quantitative analysis of multi-components via a single marker (QAMS) was developed and validated to analyze six catechins (epigallocatechin, catechin, epicatechin, epigallocatechin gallate, gallocatechin gallate, and epicatechin gallate) in oolong tea by HPLC. Catechin was chosen as the internal reference substance. The relative correction factors (RCFs) between catechin and the other five catechins were investigated for the QAMS calculation using five different types of chromatographic columns. Meanwhile, the content of each of the six analytes was also determined by a conventional external standard method. Finally, the angle cosine value revealed that there was no significant difference between the QAMS method and the external standard method. The QAMS method established in this study solved the problem of the availability and high cost of some standard substances and would be useful for providing an efficient and feasible quality assessment method for oolong tea and other botanic samples
荷叶的抗氧化活性成分
No full text荷叶为睡莲科植物莲(Nelumbo nucifera Gaertn)的干燥叶,是我国一种历史悠久的天然保健品.为阐明其抗氧化活性成分,采用正相、反相硅胶柱层析,凝胶柱层析和反相制备液相色谱等分离方法,从荷叶的甲醇提取物中分离得到18个化合物.通过波谱数据分别鉴定为荷叶碱(1),东莨菪内酯(2),黑麦草内酯(3),对甲氧基苯甲酸(4),(+)-梣皮树脂醇(5),阿魏酸(6),槲皮素(7),木犀草素(8),N-甲基阿西米诺宾(9),3,4-二羟基苯甲酸(10),4-羟基苯甲酸(11),(3S,5R,6R,7E,9S)-megastigman-7-ene-3,5,6,9-tetraol(12),儿茶素(13),腺嘌呤(14),异鼠李素-3-O-β-D-葡萄糖苷(15),异槲皮苷(16),槲皮素-3-O-β-D-吡喃木糖(1→2)-β-D-吡喃葡萄糖苷(17),槲皮素-3-O-β-D-葡萄糖醛酸苷(18),其中化合物2、4、5、8、10、11、14为首次从荷叶中分离得到.对其中的17个化合物进行了ABTS和DPPH自由基清除测试,化合物5-8,10,13,15-18表现出较强的抗氧化活性.本研究结果可为荷叶抗氧化活性的合理开发利用提供一定的科学依据
具抗病毒黄精寡糖核心片段的分离纯化与四糖结构
No full text寡糖极性大、异构体多、结构复杂,对其研究尤其是对天然来源寡糖的分离纯化与结构确认具有重要的理论和临床应用价值.以传统中药百合科黄精属植物多花黄精为原料,从分离纯化出的具有抗病毒活性的核心寡糖片段出发,制备了聚合度单一的黄精四糖,并以UV、IR、NMR、ESI-MS n、HPLC、GC-MS等多种手段对其组成与结构进行充分解析.结果表明四糖虽然聚合度单一,但仍存在多种同分异构体,且以直链结构的四糖为主,其中→2)-β-D-Fruf以及(2→1)-β-D-Fruf的含量最多,2→6)-β-D-Fruf较低,并且有的同分异构体具有典型的β-D-Fruf-(2→1)-α-D-Glcp结构,但含量甚微.本研究从具抗病毒活性的黄精寡糖分离纯化获得黄精四糖并阐明结构,可为进一步构建活性寡糖小分子和指导多糖类化合物新药设计奠定基础
DEODORIZATION OF SWINE MANURE USING A Lactobacillus STRAIN
No full textOne of the environmental problems caused by the large-scale livestock industry in China is odor pollution. Using the microbial strains with high deodorization efficiency is a feasible strategy to handle this problem. In this study, a Lactobacillus strain A2 with high efficient deodorization was isolated. To find the optimal deodorization conditions of strain A2, the deodorization efficiencies at different temperatures and inoculation quantities were tested. Our result showed that suitable temperatures (30 degrees C) and cost-effective inoculation quantity (3%) should be chosen for better growing and high efficient deodorization of strain A2. To further evaluate the deodorization efficiency of strain A2 in practical application and exploring its deodorization mechanism, a scale-up experiment was conducted. Accordingly, strain A2 exhibited high and stable deodorization efficacy of reducing more than 30% NH3, H2S and odor intensity and 40% TVOC (except on day 6 and 12) in 36 days' treatment. In addition, after the manure was incubated with strain A2, the concentrations of VFAs, indole and skatole were decreased and N and S were transformed to their less volatile forms, which would contribute to odor reduction from swine manure
The dynamic changes and interactional networks of prokaryotic community between co-digestion and mono-digestions of corn stalk and pig manure
No full textAnaerobic co-digestion is considered to be an efficient way to improve the biogas production. The abundance, dynamic and interactional networks of prokaryotic community were investigated between co-digestion and mono-digestions of corn stalk and pig manure in mesophilic batch test. Co-digestion showed higher methane production, and contributed to suitable microenvironment as well as stable prokaryotic community structure. The highest methane production was achieved with the highest relative abundance of Methanosaeta. Prokaryotic community in mono-digestions might inhibited by FA or FVFA. The functional modules in co-digestion and mono-digestion of pig manure clustered together with bigger size and higher degree, and the connections of metabolic functions were better-organized, which means high-efficient utilization of substrate and prevention of the two digestion systems crash. The partial mantel tests showed the functional modules were significantly affected by environmental factors. These results further explained that why co-digestion was more efficient than mono-digestion owing to suitable microenvironment. (C) 2016 Elsevier Ltd. All rights reserved
外施γ-聚谷氨酸对蚜虫胁迫辣椒叶片叶绿素和两种氧化还原酶的分析
No full text为探索新型无公害抗蚜方法,测试了外源施入γ-聚谷氨酸高分子聚合物的盆栽辣椒植株叶片在蚜虫胁迫后叶绿素含量、过氧化物酶、过氧化氢酶活性的变化。外施γ-聚谷氨酸的植株叶片叶绿素a和b的含量在受胁迫后随时间增加其下降趋势较对照降低;过氧化物酶和过氧化氢酶在蚜虫胁迫期间的活性较对照高。表明了外施γ-聚谷氨酸的辣椒植株叶片能够缓解由蚜虫胁迫导致的叶绿素降低的趋势并增强过氧化物酶和过氧化氢酶活性
产吲哚金黄杆菌YM5毒性相关基因及其急性经口毒性
No full text产吲哚金黄杆菌(Chryseobacterium indologenes)YM5是本实验室分离所得的一株具有高效羽毛角蛋白降解能力的革兰氏阴性菌,具有潜在的工业应用价值,但部分产吲哚金黄杆菌的相关株系被报道可能为医院条件致病菌.本研究通过测定YM5全基因组序列,分析其基因组中毒性相关功能基因,结合小鼠急性经口毒性试验,来评价YM5的生物安全性.结果显示,YM5基因组内不含毒性相关基因.YM5菌液及其羽毛发酵液对小鼠半数致死量(LD50)大于20 g/kg BW,属实际无毒级;处理14 d后,小鼠血清中谷丙转氨酶(AST)、谷草转氨酶(ALT)、尿素(BUN)、肌酐(Cre)、血糖(GLU)、总胆固醇(TC)和甘油三酯(TG)与对照组均无显著性差异(P>0.05).本研究表明YM5菌液及其羽毛发酵液对哺乳动物安全无毒副作用,可应用于工业生产