Suspension cell cultures of Maytenus hookeri Loos. (Celastraceae) in SH media were established from the calli induced from the leaves and young steins of M. hookeri on MS media with the supplement of 2 mg/L 2,4-D and ...Suspension cell cultures of Maytenus hookeri Loos. (Celastraceae) in SH media were established from the calli induced from the leaves and young steins of M. hookeri on MS media with the supplement of 2 mg/L 2,4-D and 0.1 mg/L KIN (kinetin). Ethyl acetate extract of the cultures showed inhibitory activities against Penicillium avellaneum UC-4376 which was sensitive to maytansinoids. Exhaustive isolation of natural products from a large scale of suspension cell cultures did not yield maytansine instead of affording nine compounds including one novel triterpenoid, named 2, 3-diacetoxyl maytenusone (1), and eight known ones including squalene (2), beta-sitosterol (3), 2', 3', 4-triacetyl-sitoindoside I (4), salaspermic acid (5), maytenonic acid (6), 2alpha-hydroxy-maytenonic acid (7), 6, 11,12-trihydroxy-8, 11, 13-abietrien-7-one (8) and 11, 12-dihydroxy-8, 11, 13-abietatrien-7-one (9) elucidated on the basis of 1D and 2D NMR data. The H-1-NMR and C-13-NMR assignments were made for 1, 5, 6 and 7, while the C-13-NMR assignments for 5 and 6 were revised. The chemical results suggested that the suspension cell cultures of M. hookeri did not produce maytansinoids under the reported experiment conditions.展开更多
The phylogenetic relationships of genera in the subfamily Apaturinae were examined using mtDNA sequence data from 1,471 bp of cytochrome oxidase subunit Ⅰ （COI）. The mitochondrial COI gene from a total of 16 specie...The phylogenetic relationships of genera in the subfamily Apaturinae were examined using mtDNA sequence data from 1,471 bp of cytochrome oxidase subunit Ⅰ （COI）. The mitochondrial COI gene from a total of 16 species in 11 genera were sequenced to obtain mtDNA data, along with those of 4 species obtained from GenBank, to construct the MP and the NJ trees using Athyma jina, Penthema adelma, Polyura nepenthes, and Charaxes bernardus as outgroups. The transitions at the third codon positions of the COI data set were found saturated, but they were retained for analysis, because they contain the majority of the phylogenetic information. The impacts of equal weight assumptions for all characters in the parsimonious analysis were assessed by potential alternations in clades in response to different transition/transversion weighting schemes. The results indicated four distinct major groups in Apaturinae. Moreover, several well supported and stable clades were found in the Apaturinae. The study also identified undetermined taxon groups whose positions were weakly supported and were subject to changes under different weighting schemes. Within the Apaturinae, the clustering results are approximately identical to the classical morphological classification. The mtDNA data suggest the genus Mimathyma as a monophyletic group. Lelecella limenitoides and Dilipa fenestra have close relationship with very strong support in all phylogenetic trees. It also supports the taxonomic revision of removing several species from Apatura to other genera, namely Mimathyma schrenckii, M. chevana, M. nycteis, Chitoria subcaerulea, C. fasciola, C. pallas, and Helcyra subalba.展开更多
MSH5, a member of the MutS homolog DNA mismatch repair protein family, has been shown to be required for proper homologous chromosome recombination in diverse organisms such as mouse, budding yeast and Caenorhabditis ...MSH5, a member of the MutS homolog DNA mismatch repair protein family, has been shown to be required for proper homologous chromosome recombination in diverse organisms such as mouse, budding yeast and Caenorhabditis elegans. In this paper, we show that a mutant Arabidopsis plant carrying the putative disrupted AtMSH5 gene exhibits defects during meiotic division, producing a proportion of nonviable pollen grains and abnormal embryo sacs, and thereby leading to a decrease in fertility. AtMSH5 expression is confined to meiotic floral buds, which is consistent with a possible role during meiosis. Cytological analysis of male meiosis revealed the presence of numerous univalents from diplotene to metaphase I, which were associated with a great reduction in chiasma frequencies. The average number of residual chiasmata in the mutant is reduced to 2.54 per meiocyte, which accounts for ~25% of the amount in the wild type. Here, quantitative cytogenetical analysis reveals that the residual chiasmata in Afresh5 mutants are randomly distributed among meiocytes, suggesting that AtMSH5 has an essential role during interferencesensitive chiasma formation. Taken together, the evidence indicates that AtMSH5 promotes homologous recombination through facilitating chiasma formation during prophase Ⅰ in Arabidopsis.展开更多
We investigated the chemical constituents of the fibrous root of Ophiopogon japonicus and their cytotoxicities against Hela and Hep2 cells.Ten compounds were purified by various chromatographic techniques.Their struct...We investigated the chemical constituents of the fibrous root of Ophiopogon japonicus and their cytotoxicities against Hela and Hep2 cells.Ten compounds were purified by various chromatographic techniques.Their structures were identified as 2 - hydroxylophiopogonone A（1）,5,8-dimethoxy-6-methyl-7-hydroxy-3-（2 -hydroxy-4 -methoxybenzyl） chroman-4-one（2）,5,7- dihydroxy-6,8-dimethyl-3-（4 -hydroxybenzyl） chroman-4-one（3）,7,4 -dihydroxy-5-methoxyflavanone（4）,N-trans-coumaroyltyramine （5）,N-trans-coumaroyloctopamine（6）, N-trans-feruloyltyramine （7）, 4-hydroxycinnamic acid （8）, caffeic acid （9）, and ferulic acid （10） on the basis of spectroscopic analyses. Compounds 4, 6, 7, 9, 10 were obtained from this genus for the first time. The cytotoxic activities of 1, 2, 4, 5, 6, 7, 9 and 10 against Hela and Hep2 cells are described.展开更多
文摘Suspension cell cultures of Maytenus hookeri Loos. (Celastraceae) in SH media were established from the calli induced from the leaves and young steins of M. hookeri on MS media with the supplement of 2 mg/L 2,4-D and 0.1 mg/L KIN (kinetin). Ethyl acetate extract of the cultures showed inhibitory activities against Penicillium avellaneum UC-4376 which was sensitive to maytansinoids. Exhaustive isolation of natural products from a large scale of suspension cell cultures did not yield maytansine instead of affording nine compounds including one novel triterpenoid, named 2, 3-diacetoxyl maytenusone (1), and eight known ones including squalene (2), beta-sitosterol (3), 2', 3', 4-triacetyl-sitoindoside I (4), salaspermic acid (5), maytenonic acid (6), 2alpha-hydroxy-maytenonic acid (7), 6, 11,12-trihydroxy-8, 11, 13-abietrien-7-one (8) and 11, 12-dihydroxy-8, 11, 13-abietatrien-7-one (9) elucidated on the basis of 1D and 2D NMR data. The H-1-NMR and C-13-NMR assignments were made for 1, 5, 6 and 7, while the C-13-NMR assignments for 5 and 6 were revised. The chemical results suggested that the suspension cell cultures of M. hookeri did not produce maytansinoids under the reported experiment conditions.
基金This work was supported by National Natural Science Foundation of China (No. 30570247)the Natural Science Foundation of Shanxi Province (No. 2003-1087)
文摘The phylogenetic relationships of genera in the subfamily Apaturinae were examined using mtDNA sequence data from 1,471 bp of cytochrome oxidase subunit Ⅰ （COI）. The mitochondrial COI gene from a total of 16 species in 11 genera were sequenced to obtain mtDNA data, along with those of 4 species obtained from GenBank, to construct the MP and the NJ trees using Athyma jina, Penthema adelma, Polyura nepenthes, and Charaxes bernardus as outgroups. The transitions at the third codon positions of the COI data set were found saturated, but they were retained for analysis, because they contain the majority of the phylogenetic information. The impacts of equal weight assumptions for all characters in the parsimonious analysis were assessed by potential alternations in clades in response to different transition/transversion weighting schemes. The results indicated four distinct major groups in Apaturinae. Moreover, several well supported and stable clades were found in the Apaturinae. The study also identified undetermined taxon groups whose positions were weakly supported and were subject to changes under different weighting schemes. Within the Apaturinae, the clustering results are approximately identical to the classical morphological classification. The mtDNA data suggest the genus Mimathyma as a monophyletic group. Lelecella limenitoides and Dilipa fenestra have close relationship with very strong support in all phylogenetic trees. It also supports the taxonomic revision of removing several species from Apatura to other genera, namely Mimathyma schrenckii, M. chevana, M. nycteis, Chitoria subcaerulea, C. fasciola, C. pallas, and Helcyra subalba.
基金Acknowledgments This work was supported by the National Natural Science Foundation of China （grant number 30470173）. The plant expression vector was kindly provided by Flanders Interuniversity Institute for Biotechnology （VIB）, Belgium.
文摘MSH5, a member of the MutS homolog DNA mismatch repair protein family, has been shown to be required for proper homologous chromosome recombination in diverse organisms such as mouse, budding yeast and Caenorhabditis elegans. In this paper, we show that a mutant Arabidopsis plant carrying the putative disrupted AtMSH5 gene exhibits defects during meiotic division, producing a proportion of nonviable pollen grains and abnormal embryo sacs, and thereby leading to a decrease in fertility. AtMSH5 expression is confined to meiotic floral buds, which is consistent with a possible role during meiosis. Cytological analysis of male meiosis revealed the presence of numerous univalents from diplotene to metaphase I, which were associated with a great reduction in chiasma frequencies. The average number of residual chiasmata in the mutant is reduced to 2.54 per meiocyte, which accounts for ~25% of the amount in the wild type. Here, quantitative cytogenetical analysis reveals that the residual chiasmata in Afresh5 mutants are randomly distributed among meiocytes, suggesting that AtMSH5 has an essential role during interferencesensitive chiasma formation. Taken together, the evidence indicates that AtMSH5 promotes homologous recombination through facilitating chiasma formation during prophase Ⅰ in Arabidopsis.
基金Program for Changjiang Scholar and Innovative Team in University(Grant No.985-2-063-112).
文摘We investigated the chemical constituents of the fibrous root of Ophiopogon japonicus and their cytotoxicities against Hela and Hep2 cells.Ten compounds were purified by various chromatographic techniques.Their structures were identified as 2 - hydroxylophiopogonone A（1）,5,8-dimethoxy-6-methyl-7-hydroxy-3-（2 -hydroxy-4 -methoxybenzyl） chroman-4-one（2）,5,7- dihydroxy-6,8-dimethyl-3-（4 -hydroxybenzyl） chroman-4-one（3）,7,4 -dihydroxy-5-methoxyflavanone（4）,N-trans-coumaroyltyramine （5）,N-trans-coumaroyloctopamine（6）, N-trans-feruloyltyramine （7）, 4-hydroxycinnamic acid （8）, caffeic acid （9）, and ferulic acid （10） on the basis of spectroscopic analyses. Compounds 4, 6, 7, 9, 10 were obtained from this genus for the first time. The cytotoxic activities of 1, 2, 4, 5, 6, 7, 9 and 10 against Hela and Hep2 cells are described.
