共查询到20条相似文献,搜索用时 46 毫秒
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Tun-Hai Xu Ya-Juan Xu Dong Han Hong-Feng Zhao Sheng-Xu Xie Dong-Ming Xu 《植物学报(英文版)》2007,49(2):202-206
To investigate saponins from the roots of Pulsatilla cernua (Thunb.) Bercht. et Opiz., two new compounds together with five known trlterpenold saponins were isolated. The structures of the two new trlterpenoid saponins, named cernuasides A and B, were elucidated as 3-O-[β-D-xylopyranosyl(1-)2)]-[α-L-rhamnopyranosyl(1-)4)]-α-L- arablnopyranosyl hederagenin 28-O-β-D-glucopyranosyl ester (compound 1) and 3-O-[α-L-arabinopyranosyl(1→)3)]- [α-L-rhamnopyranosyl (1→)2)]-α-L-arabinopyranosyl hederagenin 28-O-β-D-glucopyranosyl ester (compound 2) by 1D, 2D-NMR techniques, ESIMS analysis, as well as chemical methods. 相似文献
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Ling-Ling Xu Ling-Yi Kong 《植物学报(英文版)》2006,48(4):478-481
in order to investigate the active substances of Coleus forskohlii(Wiiid.) Brlq., a new labdane dlterpenold, 12- hydroxy-8,13E-labdadlen-15.olc acid, together with two 8,13-epoxylabd-14-ene-11-one dlterpenolds, 6-acetyl-1- deoxyforskolln and 6-acetyl-1,9-dldeoxyforskolln, was Isolated on the basis of various chromatographic technlques and spectroscopic methods. 相似文献
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Hunter J 《Trends in ecology & evolution》1998,13(7):281-282
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Spore morphology of 51 species of Cyclosorus in the Thelypteridaceae from China was investigated using scanning electron microscopy (SEM). The spores are monolete, bilaterosymmetric, ellipsoidal in polar view, and kidney-shaped in equatorial view. On the basis of the variation in their surface ornamentation, the spores fall into three main types. Type I: The surface of spores is echinate or perforate with fimbriate wings. 19 species belong to this type. Type Ⅱ: The surface of spores is cristate. 11 species belong to this type. Type Ⅲ: The surface of spores is echinulate. 10 species belong to this type. The remaining 11 species have spores with mixed surface ornamentation of the above three types, which are considered as intermediate types. The results are valuable for a better understanding of the taxonomy and palynology of the genus Cyclosorus. 相似文献
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A New Isoflavonoid from Belamcanda chinensis (L.) DC. 总被引:2,自引:0,他引:2
Min-Jian QIN Wen-Liang JI Zheng-Tao WANG Wen-Cai YE 《植物学报(英文版)》2005,47(11):1404-1408
A new isoflavonoid, 5, 6, 7, 3'-terahydroxy-8, 4', 5'-trimethoxyisoflavone (1), along with 10 known isoflavonoids, namely 5, 6, 7, 4'-tetrahydroxy-8-methoxyisoflavone (2), irilone (3), genistein (4), tectorigenin (5), irigenin (6), irisflorentin (7), dichotomitin (8), dimethyltectorigenin (9), iridin (10), and tectoridin (11), was isolated from the alcohol extract of the rhizomes of Belamcanda chinensis (L.) DC. The structures of these compounds were elucidated on the basis of results of spectroscopic analysis. 相似文献
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New Cytotoxic Saponins from Lysimachia davurica Ledeb. 总被引:2,自引:0,他引:2
Jing-Kui Tian Zhong-Mei Zou Li-Zhen Xu Shi-Lin Yang 《植物学报(英文版)》2006,48(2):232-235
To investigate the saponins from whole plants of Lysimachia davurica Ledeb., two new saponins named davuricoside I (compound 1) and E (compound 2) were isolated. Their chemical structures were elucidated as 3β, 16α, 28, 29-tetrihydroxy-olean-12-en-3-O-β-D-glucopyranosyl-(1→2)-β-D-glucuronopyranoside (compound 1) and 3β, 16α, 29-trihydroxy-13, 28-epoxy-oleanane-3-O-β-D-glucopyranosyl-(1→2)-β-D-glucuronopyranoside (compound 2) on the basis of their one- and two-dimensional nuclear magnetic resonance and mass spectrometry data, and chemical methods. Compound 1 showed significant cytotoxic activity against human A2780 cells. 相似文献
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Li-Jia Xu Feng Huang Si-Bao Chen Lian-Niang Li Shi-Lin Chen Pei-Gen Xiao 《植物学报(英文版)》2006,48(12):1493-1497
In the course of our study of bioactive natural products from Schisandra plants, we isolated a neolignan from an EtOAc extract of the stems of Schisandra propinqua (Wall.) Baill. The structure of the new com- pound was determined to be 4, 4-di (4-hydroxy-3-methoxyphenly)-2, 3-dimethylbutanol (compound 1) on the basis of 1H- and 13C-NMR spectra and 2D NMR methods. Eight known compounds, compounds 2-9, were also isolated and identified, of which compounds 3, 4, 6 and 9 were isolated for the first time from this plant. In addition, compounds 1-4 were evaluated for cytotoxicity by an 3-(4,5-dimethyl-2 thiazoyl)-2,5-diphenyl-2H- tetrazolium bromide (MTT) assay. Compound 1 showed significant potential cytotoxic ability in the bioassay. 相似文献
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Secreted β-galactosidase from a Flavobacterium sp. isolated from a low-temperature environment 总被引:1,自引:0,他引:1
Sørensen HP Porsgaard TK Kahn RA Stougaard P Mortensen KK Johnsen MG 《Applied microbiology and biotechnology》2006,70(5):548-557
The bacterial strain Flavobacterium sp. 4214 isolated from Greenland was found to express β-galactosidase (EC 3.2.1.23) at temperatures below 25°C. A chromosomal
library of Flavobacterium sp. 4214 was constructed in Escherichia coli, and the gene gal4214-1 encoding a β-galactosidase of 1,046 amino acids (114.3 kDa) belonging to glycosyl hydrolase family 2 was isolated. This was
the only gene encoding β-galactosidase activity that was identified in the chromosomal library. Expression levels in both
Flavobacterium sp. 4214 and in initial recombinant E. coli strains were insufficient for biochemical characterization. However, a combination of T7 promoter expression and introduction
of an E. coli host that complemented rare transfer RNA genes yielded 15 mg of β-galactosidase per liter of culture. Gal4214-1-His protein
was found to be active in monomeric conformation. The protein was secreted from the cytoplasm, probably through an N-terminal
signaling sequence. The Gal4214-1-His protein was found to have optimum activity at a temperature of 42°C, but with short-term
stability at temperatures above 25°C. 相似文献
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Xiao-Qi Zhang Guo-Cai Wang Wen-Cai Ye Qian Li Guang-Xiong Zhou Xin-Sheng Yao 《植物学报(英文版)》2006,48(9):1122-1125
To investigate diterpenoids from the aerial parts of Andrographis paniculata (Burm. f.) Nees, three new ent-labdane diterpenoids, namely 19-norandrographolides A-C (compounds 1-3), were isolated from the ethanolic extract of A. paniculata. Their structures were established by HRESIMS and NMR spectral data in combination with X-ray crystallographic analysis. 相似文献
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The amino acid sequence of cytochrome c′ from Alcaligenes sp. N.C.I.B. 11015 总被引:1,自引:1,他引:0 下载免费PDF全文
R. P. Ambler 《The Biochemical journal》1973,135(4):751-758
The amino acid sequence of the cytochrome c' from Alcaligenes sp. N.C.I.B. 11015 (Iwasaki's ;Pseudomonas denitrificans') has been determined. This organism is the only non-photosynthetic bacterium in which the protein has been found. The protein consists of a single polypeptide chain of 127 residues, with a single haem covalently attached to two cysteines. Unlike normal cytochromes c, the haem attachment site is very close to the C-terminus. The amino acid sequence around the haem attachment site is very similar to that of Chromatium vinosum D cytochrome c'. Detailed evidence for the amino acid sequence of the protein has been deposited as Supplementary Publication SUP 50022 at the British Library (Lending Division), (formerly the National Lending Library for Science and Technology), Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies may be obtained on the terms given in Biochem. J. (1973) 131, 5. 相似文献
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Li-MingFAN Hong-PingHE Yue-MaoSHEN Xiao-JiangHAO 《植物学报(英文版)》2005,47(1):120-123
Two new hetisine-type C20-diterpenoid alkaloids named spiraqine (1) and 6-hydroxylspiraqine (2), and four known alkaloids, namely spiredine (3), spiradine A (4), spiradine B (5), and spirasine V/VI (6),were isolated from Spiraea japonica L. f. var.fortunei (Planchon) Rehd. The structures of the alkaloids were elucidated using nuclear magnetic resonance analysis (1H-NMR, ^13C-NMR, DEPT, HMQC, and HMBC) and mass spectrometry data. 相似文献