裂冠牛奶菜中一新奇C_(21)甾体甙(英文)

Besides a series of normal C_(21) steroids from Marsdenia incisa incisa P.T.Li et Y.P.Li, it small amount of novel C_(21) steroidal glycoside (Ⅱ) had been isolated. The mild acidic hydrolysis of (Ⅱ) afforded genin-(Ⅰ). By spectroscopic analyses of IR, ELMS, FDMS, ~1H NMR, ~(13)C NMR (DEPT, PRFT), ~1H-~1H COSY, ~1H-~(13)C COSY for (Ⅰ) and (Ⅱ), (Ⅰ) had been deduced as B-nor (7) -6β-formyl-pregnane-3β, 5β, 8β, 12β, 14β, 17β, 20-heptatol, named neomarinogenin; (Ⅱ) had been deduced as neomarinogenin 3-O-β-D-thevetopyranosyl-(1→-4)-β-Dcymaropyranosyl-(1→4)-β-D-cymaropyranoside, named neomarinoside. Their physical and spectral data were as follows. Neomarinogenin (Ⅰ). A colorless prism from Me_2 CO, mp 202—205℃, 〔α〕_D~(17) 28.81°(MeOH, c0.05), C_(21)H_(34)O_8 (Found: C, 60.76; H, 8.19, C_(21)H_(34)O_8, requires C, 60.87. H, 8.21％); IRv_(max)~(KBr)cm~(-1): 3450 (OH), 1700 (C=O), 1050(C-O-C); EIMS m/z: 397 (M-OH), 380 (397-OH), 379, 378 (M-2H_2O), 36; (M-3H_2O), 342 (M-4H_2O), 333, 315     

Responses of nitrogen and phosphorus resorption from leaves and branches to long-term nitrogen deposition in a Chinese fir plantation北大核心CSCD

Aims Our objectives were to investigate differences in nutrient resorption between different plant organs (leaf and branch), among plants with different life spans (one-year old, two-year old and senesced), and under different duration of nitrogen (N) deposition treatments in a Chinese fir (Cunninghamia lanceolata) plantation. Methods The long-term N deposition experiment was conducted in a 12-year-old fir plantation of subtropical China. N deposition treatment was initiated in January 2004 until now, up-going 14 years. N deposition were designed at 4 levels of 0, 60, 120, and 240 kg·hm–2·a–1, indicated as N0, N1, N2, and N3, respectively, with 3 replicates for each treatment. The solution of CO(NH2)2 was sprayed on the forest floor each month. In the study, we measured N and phosphorus (P) concentrations and analyzed the pattern of nutrient resorption of mature and senescing leaves and branches. The different responses of needles N and P resorption after 7- and 14-year N deposition treatments were also compared. Important findings After 14 years of N deposition, (1) during the senescing process, leaf and branch C, N, and P content gradually decreased with increasing treatment duration, with higher content in leaf than in branch. N content decreased in the order of one-year old green leaf > two-year old green leaf > senescent leaf > one-year old living branch > two-year old living branch > senescent branch, and N3 > N2 > N1 > N0, with C:N showing the opposite trend. Senescent organs had higher C:N, N:P, and C:P than mature living organs. N deposition increased N, N:P, and C:P of mature living organs (except for the two-year old green leaf), while decreased P and C:N. (2) N resorption efficiency (REN) and P resorption efficiency (REP) of leaves and branches decreased gradually with increasing life span. REP was typically higher in leaf and branch than REN. Leaf had lower REN (28.12%) than branch (30.00%), but higher REP (45.82%) than branch (30.42%). A highly significant linear correlation existed between N:P and REN:REP in leaves and branches. (3) REN decreased but REP increased with the treatment duration of N deposition. The longer experimental duration (14 years) reduced REN by 9.85%, 3.17%, 11.71% under N1, N2, and N3 treatments, respectively, and increased REP by 71.98%, 42.25%, 9.60%, respectively, than the shorter treatment duration (7 years). In summary, the responses of essential nutrients resorption efficiency for different plant organs and life span varied with the levels and duration of N deposition treatment. REN:REP in leaf and branch were mostly driven by N:P of leaf and branch. The results highlight that nutrients resorption is significantly influenced by long-term N deposition. © Chinese Journal of Plant Ecology.     

粗枝崖摩中一个新的三萜(英文)

Five compounds were isolated from the EtOH extraction of the stem of Amoora dasyclada (How et T.Chen) C.Y.Wu (Meliaceae). On the basis of spectroscopic methods, their structures were elucidated as 24, 25-epoxy-tirucall-7-ene-3, 23-dione (1),24,25,26,27-tetranortirucall-7-ene-3-oxo-23(21)-Iactone (2),taraxerone (3),taraxerol (4)and β-sitosterol (5).Among them, compound 1 was a new triterpenoid, compounds 3-5 were firstly obtained from this plant; compound 2,an tetranortriterpenoid, was firstly isolated from natural sources, and its NMR data were assigned for the first time. Moreover, the △^7-bond and the Me-14 in compound 2 were never changed, which has never been found in other tetranortriterpenoids. And the biosynthetic pathway of tetranortriterpenoid was further discussed.     

兰花的CO_2固定(英文)

Introduction Green plants can be divided into three groups(C_3,C_4, CAM) with respect to their patternsand biochemistry of CO_2 fixation. A detailedcomparison of the various features of these threemajor groups of higher plants has been described(Bidwell 1983, Edwards and Walker 1983).     

内蒙古草原常见植物叶片δ~(13)C和δ~(15)对环境因子的响应

在中国东北样带沿线的内蒙古草原地区采集了一些常见植物的叶片样品,并测定其δ~(13)C和δ~(15)N值,分析了其统计学特征以及对环境因子(年平均降雨量和温度)的响应模式。发现东北样带草原区同时存在C_3和C_4两种不同光合途径的植物,但是C_3植物占主导地位,C_4植物数量有限。C_3植物叶片δ~(13)C随着年平均降雨量和年平均温度的升高而显著降低,反映了此区域C_3植物δ~(13)C受控于降水量和温度。C_4植物的叶片δ~(13)C值随着降雨量的增多而有轻微升高的趋势,但是C_4植物的叶片δ~(13)C值对年平均温度的响应不敏感。不论对C_3植物还是C_4植物而言,叶片δ~(15)N都随降雨量增加而显著降低,即干旱区的植物叶片δ~(15)N大于湿润地区,这说明降水是影响植物叶片δ~(15)N的一个重要因素。然而两者叶片δ~(15)N对温度的响应不敏感。     

Biological function of modified nucleotides T_(54) and ψ_(55) of yeast tRNA~(Ala)

The 3' half molecule of yeast tRNAAla (nucleotides 36-75) was hybridized with a DNA fragment (5'GGAATCGAACC 3') and the hybrid was then digested with E. coli RNase H (from Boehringer). The enzyme can specifically cleave the 3' half molecule at the 3' side of nucleotide ψ55, thus a fragment C36-ψ55 was prepared. The 3'-terminal T or Tψ of this fragment was removed by one or two cycles of periodate oxidation and $-elimination. The products were fragments C36-T54 and C36-G53. Three yeast tRNAAla fragments C56-A76, U55-A76 (with ψ55 replaced by U), U54-A76 (with T54ψ55 replaced by UU) were synthesized and ligated with three prepared fragments (C36-ψ55 C36-T54 and C36-G53) respectively by T4 RNA ligase. The products were further ligated with the 5' half molecule (nu-cleotides 1-35). Using this method, one reconstituted yeast tRNAAla (tRNAr) and two yeast tRNAAla analogs: (i) tRNAa with U55 instead of ψ55; (ii) tRNAb with U54U55 instead of T54ψ55 were synthesized. The charging and incorporation activi     

日本药局方(第11改正)收载的药用氨基酸质量标准和检测方法

<正> 1.异亮氨酸L—ィンロィシンL—Isoleucine H H H_5C_2—C—C—COOH CH_3NH_2 C_6H_(13)NO_2:131.17 本品干燥后测定含量,含L-异亮氨酸(C_6H_(13)NO_2)98.5%以上。性状本品为白色结晶或结晶性粉末,无臭,味微苦。本品稍难溶于水,难溶于冰醋酸,几乎不溶于乙醇或乙醚。本品水溶液(1→100)的pH约为6。鉴别(1)本品0.3g,加水10ml,加     

Phenylethanoid Glycosides from Picria felterrae Lour.

In our search for bioactive compounds from the whole plant of Picriafelterrae Lour., three new phenylethanoid glycosides, picfeosides A-C (1-3), along with five known phenylethanoid glycosides,namely wiedemannioside (4), acteoside (5), acteoside isomer (6), cis-acteoside isomer (7), and cis-acteoside (8), were isolated using several chromatographic purification steps, including semipreparation HPLC on RP-18. The structures of the new compounds were elucidated on the basis of extensive spectroscopic analysis.     

飞蛾藤中的新C_(30)甾体类化合物(英文)

A novel C30 sterol, (22E, 24ξ)-24-n-propylcholest-7, 22-dien-3β-ol (racemosol, 1), along withscopoletin (2), scopolin (3), umbelliferone (4), methylβ-D-frucopyranoside (5), syringaresinol-4-O-β-D-glucopyranoside (6), quercetin-3-O-β-D-glucopyranoside (7), quercetin-3-O-α-L-rhamnopyranoside (8),eupatilin (9), kaempferol-3-O-β-D-glucopyranoside (10) and (E）-N-2-(2,3-dihydroxyphenyl) ethyl cinnamamide(11), was isolated from the whole plants of Porana racemosa Roxb. Their structures were elucidatedpredominantly by spectral evidence.     

Chemical Constituents of Schisandra rubriflora Rehd. et Wils.

Schisandra rubriflora Rehd. et Wils. is a traditional Chinese medicine. To search for new and bioactive components from traditional Chinese medicines and provide scientific evidence for taxonomy, the chemical constituents of the plant were investigated by various column chromatography methods (silica gel, Sephadex LH-20, and RP-18). From the aerial parts of S. rubriflora, three new megastigmane glycosides,namely (3S, 5R, 6S, 9R)-megastigmane-3, 9-diol 3-O-[α-L-arabionfuranosyl-(1→6)-β-D-glucopyranoside](1), 7-megastigmene-3-ol-9-one 3-O-[α-L-arabionfuranosyl-(1→6)-β-D-glucopyranoside] (2), and megastigmane-3α, 4β, 9ξ-tfiol 3-O-β-D-glucopyranoside (3), along with 14 known compounds, were isolated.The structures of the new compounds were elucidated by a combination of spectroscopic and chemical methods.     

正烷烃发酵产生长链二羧酸的优良菌株U_(3-21)

我们由热带假丝酵母(Candida tropicalis)1230菌株经硝基胍及紫外线诱变,得到突变菌株U_(3-21),该菌株不仅能利用C_(10)—C_(14)正烷烃混合物产生较多的混合长链二羧酸,在最适条件下也能利用一系列单一的C_(10)—C_(18)正烷烃产生     

Effects of desertification on the C:N:P stoichiometry of soil,microbes, and extracellular enzymes in a desert grassland北大核心CSCD

Aims In order to discuss the underlying mechanism of desertification effect on the ecological stoichiometry of soil, microbes and extracellular enzymes, we studied the changes of soil, soil microbial and extracellular enzyme C:N:P stoichiometry during the desertification process in the desert grassland in Yanchi County, China. Methods The “space-for-time” method was used. Important findings The results demonstrated that: (1) Soil C, N, P contents and soil C:P, N:P significantly decreased, but soil C:N gradually increased with increasing desertification. (2) Soil microbial biomass C (MBC):soil microbial biomass P (MBP), soil microbial biomass N (MBN):MBP and soil β-1,4-glucosidase (BG):β-1,4-N-acetylglucosaminidase (NAG) gradually decreased, soil BG:alkaline phosphatase (AP) and NAG:AP basically showed an increasing trend with increasing desertification. (3) Desertification increased the soil microbial carbon use efficiency (CUE C : N and CUE C : P ) gradually, while soil microbial nitrogen use efficiency (NUE N : C ) and soil microbial phosphorus use efficiency (PUE P : C ) basically decreased. (4) Soil, soil microbial and soil extracellular enzyme C:N stoichiometry (C:N, MBC:MBN, BG:NAG) were significantly negatively correlated with the soil, soil microbial and extracellular enzyme N:P stoichiometry (N:P, MBN:MBP, NAG:AP), the soil and extracellular enzymes C:N (C:N, BG:NAG) were significantly positively correlated with the soil and extracellular enzymes C:P (C:P, BG:AP). Soil N:P was significantly positively correlated with the soil MBN:MBP, but was significantly negatively correlated with the soil NAG:AP. The analysis demonstrated that soil microbial biomass and extracellular enzyme activity changed with soil nutrient during the desertification process in the desert grassland. The co-variation relationship between soil nutrient and C:N:P stoichiometry of microbial-extracellular enzyme provides a theoretical basis for understanding the underlying mechanism of C, N, P cycling in the soil-microbial system in desert grasslands. © 2018 Editorial Office of Chinese Journal of Plant Ecology. All Rights Reserved.     

Reaction of hydroxyl radical with phenylpropanoid glycosides from Pedicularis species: a pulse radiolysis study

Using pulse radiolysis technique, the reaction between hydroxyl radical and 7 phenylpropanoidglycosides: echinacoside, verbascoside, leucosceptoside A, martynoside, pediculariosides A, M and N which were isolated from Pedicularis were examined. The rate constants of these reactions were determined by transient absorption spectra. All 7 phenylpropanoid glycosides react with hydroxyl radical at high rate constants within (0.97-1.91)×1010L · mol-1 · s-1. suggesting that they are effective hydroxyl radical scavengers. The results demonstrate that the numbers of phenolic hydroxyl groups of phenylpropanoid glycosides are directly related to their scavenging activities. The scavenging activities are likely related to o-dihydroxy group of phenylpropanoid glycosides as well.     

Effects of slow-release urea fertilizers on urease activity,microbial biomass, and nematode communities in an aquic brown soil

A field experiment was carried out at the Shenyang Experimental Station of Ecology (CAS) in order to study the effects of slow-release urea fertilizers high polymer-coated urea (SRU1), SRU1 mixed with dicyandiamide DCD (SRU2), and SRU1 mixed with calcium carbide CaC2 (SRU3) on urease activity, microbial biomass C and N, and nematode communities in an aquic brown soil during the maize growth period. The results demonstrated that the application of slow-release urea fertilizers inhibits soil urease activity and increases the soil NH4+-N content. Soil available N increment could promote its immobilization by microorganisms. Determination of soil microbial biomass N indicated that a combined application of coated urea and nitrification inhibitors increased the soil active N pool. The population of predators/omnivores indicated that treatment with SRU2 could provide enough soil NH4+-N to promote maize growth and increased the food resource for the soil fauna compared with the other treatments.     

Development and optimized pairing of mouse monoclonal antibodies for detecting hemagglutinin in novel H7 subtype influenza viruses

The H7 subtype avian influenza threatens public health with respect to poultry and humans. Thus, a specific and sensitive diagnostic test is essential for the management of H7 subtype influenza infections. In this study, five mouse monoclonal antibodies(mAbs) against hemagglutinin(HA) of influenza A/Anhui/1/2013(H7N9) were produced and characterized by the Western blot, immunofluorescence, and hemagglutination inhibition assays. All five specific mAbs reacted with the HA protein of H7N9 but not with that of H1 N1, H3 N2, or H5 N1. With the combination arrays of capture and detection antibodies, the matched pair m Abs(1 C4-coated and 2 D7-labeled) were selected and employed in a double-antibody sandwich ELISA(DASELISA). Detection limits of the sandwich ELISA were 0.45 ng mL~(–1) for the HA protein derived from A/Anhui/1/2013(H7N9);or 1 and 2 HA units/50 μL for A/Anhui/1/2013(H7N9) and A/GD/17 SF003/2016(H7N9), respectively. These anti-HA mAbs against subtype H7 and the novel DAS-ELISA provide a valuable approach for specific detection of the H7 subtype influenza virus and quantification of its HA protein, especially for the novel epidemic H7N9.     

Greenhouse gas fluxes of typical northern subtropical forest soils: Impacts of land use change and reduced precipitation北大核心CSCD

Aims: It is important to study the effects of land use change and reduced precipitation on greenhouse gas fluxes (CO2, CH4 and N2O) of forest soils. Methods: The fluxes of CO2, CH4 and N2O and their responses to environmental factors of primary forest soil, secondary forest soil and artificial forest soil under a reduced precipitation regime were explored using the static chamber and gas chromatography methods during the period from January to December in 2014. Important findings: Results indicate that CH4 uptake of primary forest soil ((-44.43 ± 8.73) μg C·m-2·h-1) was significantly higher than that of the secondary forest soil ((-21.64 ± 4.86) μg C·m-2·h-1) and the artificial forest soil ((-10.52 ± 2.11) μg C·m-2·h-1). CH4 uptake of the secondary forest soil ((-21.64 ± 4.86) μg C·m-2·h-1) was significantly higher than that of the artificial forest ((-10.52 ± 2.11) μg C·m-2·h-1). CO2 emissions of the artificial forest soil ((106.53 ± 19.33) μg C·m-2·h-1) were significantly higher than that of the primary forest soil ((49.50 ± 8.16) μg C·m-2·h-1) and the secondary forest soil ((63.50 ± 5.35) μg C·m-2·h-1) (p < 0.01). N2O emissions of the secondary forest soil ((1.91 ± 1.22) ug N·m-2·h-1) were higher than that of the primary forest soil ((1.40 ± 0.28) μg N·m-2·h-1) and the artificial forest soil ((1.01 ± 0.86) μg N·m-2·h-1). Reduced precipitation (-50%) had a significant inhibitory effect on CH4 uptake of the artificial forest soil, while it enhanced CO2 emissions of the primary forest soil and the secondary forest soil. Reduced precipitation had a significant inhibitory effect on CO2 emissions of the artificial forest soil and N2O emissions of the secondary forest (p < 0.01). Reduced precipitation promotes N2O emissions of the primary forest soil and the artificial forest soil. CH4 uptake of the primary forest and the secondary forest soil increased significantly with the increase of soil temperature under natural and reduced precipitation. CO2 and N2O emission fluxes of the primary forest soil, secondary forest soil and artificial forest soil were positively correlated with soil temperature (p < 0.05). Soil moisture inhibited CH4 uptake of the secondary forest soil and the artificial forest soil (p < 0.05). CO2 emissions of the primary forest soil were significantly positively correlated with soil moisture (p < 0.05). N2O emissions of primary forest soil and secondary forest soil were significantly correlated with the nitrate nitrogen content (p < 0.05). It was implied that reduced precipitation and land use change would have significant effects on greenhouse gas emissions of subtropical forest soils.     

Iridoid Glycosides from Pedicularis dolichocymba Hand.-Mazz.

During investigation of the chemical constituents of the whole plant ethanol extract of Pedlcularis dollchocymba Hand.-Mazz. （Scrophularlaceae）, four new irldold glycosides, dolichocymbosides A （compound 1）, B （compound 2）, C （compound 3） and D （compound 4）, were Isolated. Their structures were determined based on spectral data Including 1D and 2D-nuclear magnetic resonance spectroscopy （^1H-^1H COSY, HSQC, HMBC, ROESY） and FAB-MS.     

Effluxes of nitrous oxide,methane and carbon dioxide and their responses to increasing nitrogen deposition in the Gurbantünggüt Desert of Xinjiang,China北大核心CSCD

Aims Desert soils play an important role in the exchange of major greenhouse gas (GHG) between atmosphere and soil. However, many uncertainties existed in understanding of desert soil role, especially in efflux evaluation under a changing environment. Methods We conducted plot-based field study in center of the Gurbantünggüt Desert, Xinjiang, and applied six rates of simulated nitrogen (N) deposition on the plots, i.e. 0 (N0), 0.5 (N0.5), 1.0 (N1), 3.0 (N3), 6.0 (N6) and 24.0 (N24) g·m-2·a-1. The exchange rates of N2O, CH4 and CO2 during two growing seasons were measured for two years after N applications. Important findings The average efflux of two growing seasons from control plots (N0) were 4.8 μg·m-2·h-1, -30.5 μg·m-2·h-1 and 46.7 mg·m-2·h-1 for N2O, CH4 and CO2, respectively. The effluxes varied significantly among seasons. N0, N0.5 and N1 showed similar exchange of N2O in spring and summer, which was relatively higher than in autumn, while the rates of N2O in N6 and N24 were controled by time points of N applications. The uptake of CH4 was relatively higher in both spring and summer, and lower in autumn. Emission of CO2 changed minor from spring to summer, and greatly decreased in autumn in the first measured year. In the second year, the emission patterns were changed by rates of N added. N additions generally stimulated the emission of N2O, while the effects varied in different seasons and years. In addition, no obvious trends were found in the emission factor of N2O. The uptake of CH4 was not significantly affected by N additions. N additions did not change CO2 emissions in the first year, while high N significantly reduced the CO2 emissions in spring and summer of the second year, without affected in autumn. Structure equation model analysis on the factors suggested that N2O, CH4 and CO2 were dominantly affected by the N application rates, soil temperature or moisture and plant density, respectively. Over the growing seasons, both the net efflux and the global warming potential caused by N additions were small.     

Effects of N on Plant Response to Heat-wave: A Field Study with Prairie Vegetation

More intense, more frequent, and longer heat-waves are expected in the future due to global warming, which could have dramatic ecological impacts. Increasing nitrogen (N) availability and its dynamics will likely impact plant responses to heat stress and carbon (C) sequestration in terrestrial ecosystems. This field study examined the effects of N availability on plant response to heat-stress (HS) treatment in naturally-occurring vegetation. HS (5 d at ambient or 40.5 ℃) and N treatments (±N) were applied to 16 1 m2 plots in restored prairie vegetation dominated by Andropogon gerardii (warm-season C4 grass) and Solidago canadensis (warm-season C3 forb). Before, during, and after HS, air, canopy, and soil temperature were monitored; net CO2 assimilation (Pn), quantum yield of photosystem Ⅱ (φPsⅡ), stomatal conductance (gs), and leaf water potential (Ψw) of the dominant species and soil respiration (Rsolf) of each plot were measured daily during HS. One week after HS, plots were harvested, and C% and N% were determined for rhizosphere and bulk soil, and above-ground tissue (green/senescent leaf, stem, and flower). Photosynthetic N-use efficiency (PNUE) and N resorption rate (NRR) were calculated. HS decreased Pn, gs, Ψw, and PNUE for both species, and N treatment generally increased these variables (±HS), but often slowed their poat-HS recovery. Aboveground biomass tended to decrease with HS in both species (and for green leaf mass in S. canadensis), but decrease with N for ,4. gerardii and increase with N for S. canadensis. For A. gerardii, HS tended to decrease N% in green tissues with N, whereas in S. canadensis, HS increased N% in green leaves.Added N decreased NRR for A. gerardii and HS increased NRR for S. canadensis. These results suggest that heat waves,though transient, could have significant effects on plants, communities, and ecosystem N cycling, and N can influence the effect of heat waves.