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1.
To search for new and bioactive minor components from traditional Chinese medicines, a new compound, named jujuphenoside (1), was isolated from the seeds of Ziziphus jujuba var. spinosa (Bunge) Hu. The structure ofjujuphenoside was elucidated by spectral and chemical methods, particularly twodimensional nuclear magnetic resonance analysis. Together with the new compound, 22 known compounds were also isolated and identified from the seeds of Z. jujuba var. spinosa, among which, epiceanothic acid (2) was first obtained from natural resources, whereas compounds 7-16 were first obtained from this plant.  相似文献   

2.
The taxonomy of Lepisorus (J. Sm.) Ching sect. Lepisorus in China was revised based on herbarium specimen examinations, field observations, and microscopic study of rhizome scales, soral paraphyses, leaf epidermis, and spores. As a result, nine species were recognized: Lepisorus macrosphaerus (Baker) Ching, Lepisorus asterolepis (Baker) Ching, Lepisorus marginatus Ching, Lepisorus kuchenensis (Y.C. Wu) Ching, Lepisorus megasorus (C. Chr.) Ching, Lepisorus kawakamii (Hayata) Tagawa, Lepisorus subsessilis Ching & Y.X. Lin, Lepisorus affinis Ching, and Lepisorus nudus (Hook.) Ching. Lepisorus kawakamii (Hayata) Tagawa was reinstated; Lepisorus gyirongensis Ching & S.K. Wu and Lepisorus longus Ching were reduced to synonyms ofL. nudus and L. affinis, respectively. The subdivision ofLepisorus macrosphaerus was not accepted. Rhizome scales and paraphyses are the most useful characters for species delimitation as well as for infrageneric classification. Characteristics of the leaf epidermis and spore ornamentation are usually stable and thus of great significance in understanding the relationships among groups within the genus.  相似文献   

3.
赵世民  祖国诚 《遗传学报》1999,26(6):711-714
采用叶盘法将兔将御素NP-1基因导入毛白杨后,经PCR分析、Southern杂交检测与筛获得了转基因植株,并经体外抑菌实验表明,转NP-1基因毛白杨植株组织提取物对某些微生物的生长具有明显的抑制作用。  相似文献   

4.
In this research, 3-day-old etiolated wheat seedlings of Triticum aestivum L. cv. Ceyhan-99 (salt-sensitive) and T. durum Desf. cv. Firat-93 (salt-tolerant) were grown in control and salt (150 mmol/L NaCl) treatments at a 15/25℃ temperature regime in the light for 12 days. Soluble proteins extracted from the first leaf tissues of two cultivars were analyzed by twodimensional (2-D) electrophoresis in order to detect NaCl-induced changes. The soluble leaf protein profiles of cultivars were observed to be similar. However, quantitative differences in 74 proteins were detected in the salt treatment group, compared to the control. Among the 74 protein spots, 14 were common for two cultivars. As a result of NaCl treatment, two low-molecular-weight (LMW) proteins (28.9 and 30.0 kDa) and one intermediate-molecular-weight (IMW) protein (44.3 kDa) in cv. Ceyhan-99 and six LMW proteins (18.6, 19.4, 25.7, 25.9, 26 and 27.6 kDa) in cv. Firat-93 were newly synthesized. The newly synthesized proteins were specific to each cultivar. In the Firat-93 cultivar, four proteins with LMW (24.8-27.9 kDa) were completely lost in NaCl treatment. Moreover, these four protein spots were not observed in both protein profiles of cv. Ceyhan-99. Most of these proteins were in acidic character (pl 〈6.0-6.9) and low molecular weight (〈31.6 kDa). It is suggested that the newly synthesized or completely lost LMW proteins may be important for cultivars differing in sensitivity towards NaCl.  相似文献   

5.
The chlorophyll fluorescence (CF) signature emitted from vegetation provides an abundance of information regarding photosynthetics activity and has been used as a powerful tool to obtain physiological information of plant leaves in a non-invasive manner. CF is difficult to quantify because the CF signal is obscured by reflected light. In the present study, the apparent reflectance spectra of wheat (Triticum aestivum L.) leaves were measured under illuminations with and without filtering by three specially designed long-wave pass edge filters; the cut-off wavelengths of the three filters were 653.8, 678.2, and 694. l nm at 50% of maximum transmittance. The CF spectra could be derived as the reflectance difference spectra of the leaves under illuminations with and without the long wave pass edge filters. The ratio of the reflectance difference at 685 and 740 nm (Dif685/Dif740) was linear correlated with the CF parameters (maximal photochemical efficiency Fv/Fm, and the yield of quantum efficiency) measured by the modulated fluorometer. In addition, the ratio reflected the water stress status of the wheat leaf, which was very high when water deficiency was serious. This method provides a new approach for detecting CF and the physiological state of crops.  相似文献   

6.
The fungus-growing ants (Tribe Attini) are a New World group of〉 200 species, all obligate symbionts with a fungus they use for food. Four attine taxa are known to be social parasites of other attines. Acromyrmex ( Pseudoatta) argentina argentina and Acromyrmex (Pseudoatta) argentina platensis (parasites of Acromyrmex lundi), and Acromyrmex sp. (a parasite of Acromyrmex rugosus) produce no worker caste. In contrast, the recently discovered Acromyrmex insinuator (a parasite of Acromyrmex echinatior) does produce workers. Here, we describe a new species, Acromyrmex ameliae, a social parasite of Acromyrmex subterraneus subterraneus and Acromyrmex subterraneus brunneus in Minas Gerais, Brasil. Like A. insinuator, it produces workers and appears to be closely related to its hosts. Similar social parasites may be fairly common in the fungus-growing ants, but overlooked due to the close resemblance between parasite and host workers.  相似文献   

7.
The supplementation with 50, 100 and 150μg/mL potassium chloride to the fifth instar larvae of the silkworm Bombyx mori on fat body glycogen, protein, total lipids and haemolymph protein and trehalose were analyzed. The fat body glycogen and protein and haemolymph protein were increased significantly in all the treated groups; whereas fat body total lipids increased only in 100 and 150μg/mL and haemolymph trehalose increased only in 150μg/mL potassium chloride-treated groups when compared with those of the corresponding parameters of the carrier controls.  相似文献   

8.
从匙叶八角(Illicium spathulatum)果实中分离得到一个新的倍半新木脂素,通过现代波谱技术确定其结构为7′,8′-反式-7″,8″-顺式-5,3′,3″-三甲氧基倍半新木脂素。  相似文献   

9.
蜈蚣(Scolopendra subspinipes mutilans L.Koch)...   总被引:3,自引:0,他引:3  
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10.
The loss of carbon through root respiration Is an Important component of grassland carbon budgets. However, few data are available concerning the contribution of root respiration to total soil respiration in grasslands in China. We Investigated seasonal variations of soil respiration rate, root blomaaa, microbial blomaaa C and organic C content of the soil In a semi-arid Leymus chinensis (Trin.) Tzvel. grassland of northeast China during the 2002 growing season (from May to September). The linear regression relationship between soil respiration rate and root blomaaa was used to determine the contribution of root respiration to total soil respiration. Soil respiration rate ranged from 2.5 to 11.9 g C/m^2 per d with the maximum in late June and minimum In September. The microbial blomaaa C and organic C content of the soil ranged from 0.3 to 1.5 g C/m^2 and from 29 to 34 g C/kg respectively. Root blomaaa had two peaks, In early June (1.80 kg/m^2) and mid-August (1.73 kg/m^2). Root respiration rate peaked In mid-August (6.26 g C/m^2 per d), whereas microbial respiration rate peaked In late June (7.43 g C/m^2 per d). We estimated that the contribution of root respiration to total soil respiration during the growing season ranged from 38% to 76%.  相似文献   

11.
12.
    
The new catecholic xanthone, 1,3,7-trihydroxy-4-(1,1-dimethyl-2-propenyl)-5,6-(2,2-dimethylchromeno)-xanthone (1), was isolated from the root bark of Cudrania tricuspidata together with seven known xanthones. The structures were fully characterized by analysis of physical and spectral (UV, IR, mass, and NMR) data. Relationships between the structural characteristics of xanthones and their antioxidant activities (DPPH, superoxide, and hydroxyl radical) were studied. Among the range of catecholic xanthones, 6,7-dihydroxyl xanthones (3–8) exhibited a strong scavenging effect on the DPPH radical. When one of the catecholic hydroxyl groups was protected as in compounds 1 and 2, DPPH radical scavenging activity was markedly decreased (IC50 > 200 μM). DPPH activities were consistent with electrochemical response by cyclic voltammetry. Interestingly, compounds (1, 2) which had the weak activities on DPPH, exhibited both potent superoxide and hydroxyl radical scavenging activities. The strong activity on the hydroxyl radical of compounds (1, 2) could be rationalized by their chelating effect with iron (Fe2+) due to a redshift of its complex. The catecholic xanthones (3–8), being able to convert quinone methide intermediate, showed potent cytotoxicities against human cancer cell lines (HT-29, HL-60, SK-OV3, AGS, and A549). In particular, compounds 3, 6, and 7 had strong cytotoxic activities against AGS (LD50 < 5 μM). DNA fragmentation patterns induced by catecholic xanthones revealed that tumor cell death was due to apoptosis.  相似文献   

13.
为探讨柘叶Cudrania tricuspidata饲养家蚕Bombyx mori易感染核多角体病毒(BmNPV)的机制, 本实验比较研究了分别以柘叶和桑叶Morus alba饲养家蚕后其消化液中抗病毒蛋白活性的差异。结果表明: 家蚕经柘叶饲养后消化液中红色荧光蛋白(red fluorescent protein, RFP)的强度无明显变化, 但柘叶饲养蚕消化液中脂肪酶、 胰蛋白酶的活性显著低于桑叶饲养蚕, 柘叶饲养蚕消化液中脂肪酶和胰蛋白酶的活性分别为1 421.71±202.60 U/L和19.67±8.17 U/mL, 桑叶饲养蚕脂肪酶和胰蛋白酶的活性分别为1 976.03±139.92 U/L和199.18±181.71 U/mL。这些结果说明, 消化液中脂肪酶和胰蛋白酶的活性水平低与柘叶饲养蚕易感染核型多角体病毒(BmNPV)可能相关。  相似文献   

14.
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16.
Prenylated flavonoids are attractive specialized metabolites with a wide range of biological activities and are distributed in several plant families. The prenylation catalyzed by prenyltransferases represents a Friedel-Crafts alkylation of the flavonoid skeleton in the biosynthesis of natural prenylated flavonoids and contributes to the structural diversity and biological activities of these compounds. To date, all identified plant flavonoid prenyltransferases (FPTs) have been identified in Leguminosae. In the present study two new FPTs, Morus alba isoliquiritigenin 3′-dimethylallyltransferase (MaIDT) and Cudrania tricuspidata isoliquiritigenin 3′-dimethylallyltransferase (CtIDT), were identified from moraceous plants M. alba and C. tricuspidata, respectively. MaIDT and CtIDT shared low levels of homology with the leguminous FPTs. MaIDT and CtIDT are predicted to be membrane-bound proteins with predicted transit peptides, seven transmembrane regions, and conserved functional domains that are similar to other homogentisate prenyltransferases. Recombinant MaIDT and CtIDT were able to regioselectively introduce dimethylallyl diphosphate into the A ring of three flavonoids with different skeleton types (chalcones, isoflavones, and flavones). Phylogenetic analysis revealed that MaIDT and CtIDT are distantly related to their homologs in Leguminosae, which suggests that FPTs in Moraceae and Leguminosae might have evolved independently. MaIDT and CtIDT represent the first two non-Leguminosae FPTs to be identified in plants and could thus lead to the identification of additional evolutionarily varied FPTs in other non-Leguminosae plants and could elucidate the biosyntheses of prenylated flavonoids in various plants. Furthermore, MaIDT and CtIDT might be used for regiospecific prenylation of flavonoids to produce bioactive compounds for potential therapeutic applications due to their high efficiency and catalytic promiscuity.  相似文献   

17.
为研究醉鱼草果实水部位化学成分及其神经保护作用,利用多种色谱分离技术从醉鱼草果实水部位中分离得到10个化合物。结合现代光谱技术对分离得到的化合物进行结构鉴定,分别为密蒙花苷C(1)、异毛蕊花糖苷(2)、毛蕊花糖苷(3)、4′-hydroxyphenyl ethyl vanillate(4)、6-O-香草酰筋骨草苷(5)、syringaresinol-4′-O-β-D-glucopyranoside(6)、刺五加苷B(7)、松柏苷(8)、醉鱼草皂苷Ⅳb(9)、6-O-(3"-O-p-coumaroyl-α-L-rhamnopyranosyl)catalpol(10),其中化合物4、6、7、8、10为首次从醉鱼草属植物中分离得到,化合物2、3为首次从醉鱼草果实中分离得到;利用MPP+诱导的SH-SY5Y细胞模型对化合物1、5、6、7的神经保护作用进行活性筛选,结果显示四个化合物均能使细胞存活率显著提高。  相似文献   

18.
19.
A new flavone, asplenetin, has been isolated from Launea asplenifolia and characterized as 5,7,3′,4′,5′-pentahydroxy-3-(3-methylbutyl)flavone. Its glycoside, asplenetin 5-O-neohesperidoside, is also reported.  相似文献   

20.
Seven flavonoids have been isolated from the seeds of Lonchocarpus costaricensis of which four appear to be novel. The new compounds have been identified as the β-hydroxychalcone demethylpraecansone-B and the flavanones 7-(3,3-dimethylallyloxy)-8-(3-hydroxy-3-methyl-trans-but-1-enyl)flavanone, 7-(3,3-dimethylallyloxy)-8-(3,3-dimethylallyl)-5-methoxyflavanone and 8-(3,3-dimethylallyl)-5,7-dimethoxyflavanone.  相似文献   

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